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Sample records for basin southeastern california

  1. Late Tertiary and Quaternary geology of the Tecopa basin, southeastern California

    Energy Technology Data Exchange (ETDEWEB)

    Hillhouse, J.W.

    1987-12-31

    Stratigraphic units in the Tecopa basin, located in southeastern California, provide a framework for interpreting Quaternary climatic change and tectonism along the present Amargosa River. During the late Pliocene and early Pleistocene, a climate that was appreciably wetter than today`s sustained a moderately deep lake in the Tecopa basin. Deposits associated with Lake Tecopa consists of lacustrine mudstone, conglomerate, volcanic ash, and shoreline accumulations of tufa. Age control within the lake deposits is provided by air-fall tephra that are correlated with two ash falls from the Yellowstone caldera and one from the Long Valley caldera. Lake Tecopa occupied a closed basin during the latter part, if not all, of its 2.5-million-year history. Sometime after 0.5 m.y. ago, the lake developed an outlet across Tertiary fanglomerates of the China Ranch Beds leading to the development of a deep canyon at the south end of the basin and establishing a hydrologic link between the northern Amargosa basins and Death Valley. After a period of rapid erosion, the remaining lake beds were covered by alluvial fans that coalesced to form a pediment in the central part of the basin. Holocene deposits consist of unconsolidated sand and gravel in the Amargosa River bed and its deeply incised tributaries, a small playa near Tecopa, alluvial fans without pavements, and small sand dunes. The pavement-capped fan remnants and the Holocene deposits are not faulted or tilted significantly, although basins to the west, such as Death Valley, were tectonically active during the Quaternary. Subsidence of the western basins strongly influenced late Quaternary rates of deposition and erosion in the Tecopa basin.

  2. California Air Basins

    Data.gov (United States)

    California Department of Resources — Air ResourcesCalifornia Air Resources BoardThe following datasets are from the California Air Resources Board: * arb_california_airbasins - California Air BasinsThe...

  3. Climate change impacts on southeastern U.S. basins

    Science.gov (United States)

    Georgakakos, Aris P.; Yao, Huaming

    2000-01-01

    The work described herein aims to assess the impacts of potential climate change on the Apalachicola-Chattahoochee-Flint (ACF) and Alabama-Coosa-Talapoosa (ACT) river basins in the Southeastern US. The assessment addresses the potential impacts on watershed hydrology (soil moisture and streamflow) and on major water uses including water supply, drought management, hydropower, environmental and ecological protection, recreation, and navigation. This investigation develops new methods, establishes and uses an integrated modeling framework, and reaches several important conclusions that bear upon river basin planning and management. Although the specific impacts vary significantly with the choice of the GCM scenario, some general conclusions are that (1) soil moisture and streamflow variability is expected to increase, and (2) flexible and adaptive water sharing agreements, management strategies, and institutional processes are best suited to cope with the uncertainty associated with future climate scenarios.

  4. Geochemical conditions and the occurrence of selected trace elements in groundwater basins used for public drinking-water supply, Desert and Basin and Range hydrogeologic provinces, 2006-11: California GAMA Priority Basin Project

    Science.gov (United States)

    Wright, Michael T.; Fram, Miranda S.; Belitz, Kenneth

    2015-01-01

    The geochemical conditions, occurrence of selected trace elements, and processes controlling the occurrence of selected trace elements in groundwater were investigated in groundwater basins of the Desert and Basin and Range (DBR) hydrogeologic provinces in southeastern California as part of the Priority Basin Project (PBP) of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA PBP is designed to provide an assessment of the quality of untreated (raw) groundwater in the aquifer systems that are used for public drinking-water supply. The GAMA PBP is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey and the Lawrence Livermore National Laboratory.

  5. Paleohydrogeology of the San Joaquin basin, California

    Science.gov (United States)

    Wilson, A.M.; Garven, G.; Boles, J.R.

    1999-01-01

    Mass transport can have a significant effect on chemical diagenetic processes in sedimentary basins. This paper presents results from the first part of a study that was designed to explore the role of an evolving hydrodynamic system in driving mass transport and chemical diagenesis, using the San Joaquin basin of California as a field area. We use coupled hydrogeologic models to establish the paleohydrogeology, thermal history, and behavior of nonreactive solutes in the basin. These models rely on extensive geological information and account for variable-density fluid flow, heat transport, solute transport, tectonic uplift, sediment compaction, and clay dehydration. In our numerical simulations, tectonic uplift and ocean regression led to large-scale changes in fluid flow and composition by strengthening topography-driven fluid flow and allowing deep influx of fresh ground water in the San Joaquin basin. Sediment compaction due to rapid deposition created moderate overpressures, leading to upward flow from depth. The unusual distribution of salinity in the basin reflects influx of fresh ground water to depths of as much as 2 km and dilution of saline fluids by dehydration reactions at depths greater than ???2.5 km. Simulations projecting the future salinity of the basin show marine salinities persisting for more than 10 m.y. after ocean regression. Results also show a change from topography-to compaction-driven flow in the Stevens Sandstone at ca. 5 Ma that coincides with an observed change in the diagenetic sequence. Results of this investigation provide a framework for future hydrologic research exploring the link between fluid flow and diagenesis.

  6. Geochemistry of spring water, southeastern Uinta Basin, Utah and Colorado

    Science.gov (United States)

    Kimball, Briant A.

    1981-01-01

    The chemical quality of water in the southeastern Uinta Basin, Utah and Colorado, is important to the future development of the abundant oil-shale resources of the area. This report examines the observed changes in chemistry as water circulates in both shallow and deep ground-water systems. Mass-balance and mass- transfer calculations are used to define reactions that simulate the observed water chemistry in the mixed sandstone, siltstone, and carbonate lithology of the Green River Formation of Tertiary age.The mass-transfer calculations determine a reaction path particular to this system. The early dominance of calcite dissolution produces a calcium carbonate water. After calcite saturation, deeper circulation and further rock-water interaction cause the reprecipitation of calcite, the dissolution of dolomite and plagioclase, and the oxidation of pyrite; all combining to produce a calcium magnesium sodium bicarbonate sulfate water. The calculations suggest that silica concentrations are controlled by a kaolinite-Ca-montmorillonite phase boundary. Close agreement of mineral-saturation indices calculated by both an aqueous-equilibrium model and the mass-transfer model support the selection of reactions from the mass-transfer calculations.

  7. The Pennsylvanian-early permian bird spring carbonate shelf, Southeastern California: Fusulinid biostratigraphy, paleogeographic evolution, and tectonic implications

    Science.gov (United States)

    Stevens, C.H.; Stone, P.

    2007-01-01

    The Bird Spring Shelf in southeastern California, along with coeval turbidite basins to the west, records a complex history of late Paleozoic sedimentation, sea-level changes, and deformation along the western North American continental margin. We herein establish detailed correlations between deposits of the shelf and the flanking basins, which we then use to reconstruct the depositional history, paleogeography, and deformational history, including Early Permian emplacement of the regionally significant Last Chance allochthon. These correlations are based on fusulinid faunas, which are numerous both on the shelf and in the adjoining basins. Study of 69 fusulinid species representing all major fusulinid-bearing Pennsylvanian and Lower Permian limestone outcrops of the Bird Spring Shelf in southeastern California, including ten new species of the genera Triticites, Leptotriticites, Stewartina, Pseudochusenella, and Cuniculinella, forms the basis for our correlations. We group these species into six fusulinid zones that we correlate with fusulinid-bearing strata in east-central and southern Nevada, Kansas, and West Texas, and we propose some regional correlations not previously suggested. In addition, we utilize recent conodont data from these areas to correlate our Early Permian fusulinid zones with the standard Global Permian Stages, strengthening their chronostratigraphic value. Our detailed correlations between the fusulinid-bearing rocks of the Bird Spring Shelf and deep-water deposits to the northwest reveal relationships between the history of shelf sedimentation and evolution of basins closer to the continental margin. In Virgilian to early Asselian (early Wolfcampian) time (Fusulinid Zones 1 and 2), the Bird Spring Shelf was flanked on the west by the deep-water Keeler Basin in which calcareous turbidites derived from the shelf were deposited. In early Sakmarian (early middle Wolfcampian) time (Fusulinid Zone 3), the Keeler Basin deposits were uplifted and

  8. Groundwater quality in the Northern Coast Ranges Basins, California

    Science.gov (United States)

    Mathany, Timothy M.; Belitz, Kenneth

    2015-01-01

    The Northern Coast Ranges (NOCO) study unit is 633 square miles and consists of 35 groundwater basins and subbasins (California Department of Water Resources, 2003; Mathany and Belitz, 2015). These basins and subbasins were grouped into two study areas based primarily on locality. The groundwater basins and subbasins located inland, not adjacent to the Pacific Ocean, were aggregated into the Interior Basins (NOCO-IN) study area. The groundwater basins and subbasins adjacent to the Pacific Ocean were aggregated into the Coastal Basins (NOCO-CO) study area (Mathany and others, 2011).

  9. Environment Assessment, Resource Evaluation, and Underground Science in Southeastern California and Southwestern Nevada

    International Nuclear Information System (INIS)

    Wang, J.

    2004-01-01

    The geologically unique region of southeastern California and southwestern Nevada has both very high peaks and the lowest point, Death Valley, in the U.S. These features have significant effects on research in nuclear waste disposal, climate change, and evaluation of the potential for underground science in that region. These areas of scientific research can be further coordinated and expanded: (1) For nuclear waste, the studies of the Yucca Mountain site northeast of Death Valley contribute to the understanding of unsaturated and saturated flow and transport in an arid environment, with sensitivity to infiltration, under present-day and future climate conditions. (2) For climate research, water resources in hydrographic basins are being evaluated, in light of the prediction that there will be large decreases in snow accumulations (by 50%) in the 21st century. Further coupling of general circulation models with subsurface processes can increase understanding of hydrological responses to climate changes, with findings potentially applicable to other climate-stressed regions. (3) The combination of earth science testing and physics experimentation in underground laboratories signifies a promising research opportunity for the Death Valley region. Telescope Peak (along the western border of Death Valley), Boundary Peak (along the California-Nevada border), Mount Charleston (outside Las Vegas), and Mt. Tom (along the Pine Creek valley) are potential sites, with horizontal tunneling below peaks from valley floors to reach the depth required for low cosmic ray background. The use of existing mines in the region could also be explored for research in both earth science at different depths and the next generation of physics (e.g., neutrino mass measurements)

  10. 77 FR 39184 - Grapes Grown in Designated Area of Southeastern California; Increased Assessment Rate

    Science.gov (United States)

    2012-07-02

    ...; ] DEPARTMENT OF AGRICULTURE Agricultural Marketing Service 7 CFR Part 925 Grapes Grown in Designated Area of... ``Act.'' The Department of Agriculture (USDA) is issuing this rule in conformance with Executive Order... in a designated area of southeastern California. They are familiar with the Committee's needs and...

  11. 76 FR 21620 - Grapes Grown in Designated Area of Southeastern California; Increased Assessment Rate

    Science.gov (United States)

    2011-04-18

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF AGRICULTURE... Department of Agriculture (USDA) is issuing this rule in conformance with Executive Order 12866. This rule... southeastern California. They are familiar with the Committee's needs and with the costs for goods and services...

  12. 76 FR 7119 - Grapes Grown in Designated Area of Southeastern California; Increased Assessment Rate

    Science.gov (United States)

    2011-02-09

    ...; ] DEPARTMENT OF AGRICULTURE Agricultural Marketing Service 7 CFR Part 925 Grapes Grown in Designated Area of... ``Act.'' The Department of Agriculture (USDA) is issuing this rule in conformance with Executive Order... in a designated area of southeastern California. They are familiar with the Committee's needs and...

  13. Ground water in the southeastern Uinta Basin, Utah and Colorado

    Science.gov (United States)

    Holmes, Walter F.; Kimball, Briant A.

    1987-01-01

    The potential for developing oil-shale resources in the southeastern Uinta Basin of Utah and Colorado has created the need for information on the quantity and quality of water available in the area. This report describes the availability and chemical quality of ground water, which might provide a source or supplement of water supply for an oil-shale industry. Ground water in the southeastern Uinta Basin occurs in three major aquifers. Alluvial aquifers of small areal extent are present i n val ley-f i 11 deposits of six major drainages. Consolidated-rock aquifers include the birds's-nest aquifer i n the Parachute Creek Member of the G reen River Formation, which is limited to the central part of the study area; and the Douglas Creek aquifer, which includes parts of the Douglas Creek Member of the Green River Formation and parts of the intertonguing Renegade Tongue of the Wasatch Formation; this aquifer underlies most of the study area.The alluvial aquifers are recharged by infiltration of streamflow and leakage from consolidated-rock aquifers. Recharge is estimated to average about 32,000 acre-feet per year. Discharge from alluvial aquifers, primarily by evapotranspiration, also averages about 32,000 acre-feet per year. The estimated volume of recoverable water in storage in alluvial aquifers is about 200,000 acre-feet. Maximum yields to individual wells are less than 1,000 gallons per minute.Recharge to the bird's-nest aquifer, primarily from stream infiltration and downward leakage from the overlying Uinta Formation, is estimated to average 670 acre-feet per year. Discharge from the bird's-nest aquifer, which is primarily by seepage to Bitter Creek and the White River, is estimated to be at 670 acre-feet per year. The estimated volume of recoverable water in storage in the bird's-nest aquifer is 1.9 million acre-feet. Maximum yields to individual wells in some areas may be as much as 5,000 gallons per minute. A digital-computer model of the flow system was used

  14. Wildlife habitats in managed rangelands—the Great Basin of southeastern Oregon: introduction.

    Science.gov (United States)

    Chris Maser; Jack Ward. Thomas

    1983-01-01

    The need for a way by which rangeland managers can account for wildlife in land-use planning, in on-the-ground management actions, and in preparation of environmental impact statements is discussed. Principles of range-land-wildlife interactions and management are described along with management systems. The Great Basin of southeastern Oregon was selected as a well-...

  15. The Basin and Range Province in Utah, Nevada, and California

    Science.gov (United States)

    Nolan, Thomas B.

    1943-01-01

    In this report an attempt has been made to summarize and in places to interpret the published information that was available through 1938 on the geology of those parts of Nevada, California, and Utah that are included in the geologic province known as the Basin and Range province. This region includes most of the Great Basin, from which no water flows to the sea, as well as part of the drainage basin of the lower Colorado River. It is characterized by numerous parallel, linear mountain ranges that are separated from one another by wide valleys or topographic basins. All the major divisions of geologic time are represented by the rocks exposed in this region. The oldest are of pre-Cambrian age and crop out chiefly along the eastern and southern borders. They have been carefully studied at only a few localities, and the correlation and extent of the subdivision so far recognized is uncertain. There appear to be at least three series of pre-Cambrian rocks which are probably separated from one another by profound unconformities. Large masses of intrusive igneous rocks have been recognized only in the oldest series. During the Paleozoic era the region was a part of the Cordilleran geosyncline, and sediments were deposited during all of the major and most of the minor subdivisions of the era. There are thick and widespread accumulations of Cambrian and Ordovician strata, the maximum aggregate thickness possibly exceeding 23,000 feet. The eastern and western boundaries of the province were approximately those of the area of rapid subsidence within the geosyncline, though the axes of maximum subsidence oscillated back and forth during the two periods. The Silurian and Devonian seas, on the other hand, extended beyond the province and, possibly as a consequence, are represented by much thinner sections - of the order of 6,000 feet. At the end of the Devonian period the geosyncline was split by the emergence of a geanticline in western Nevada, and Mississippian and

  16. Waterford Formation in the south-eastern Karoo: Implications for basin development

    Directory of Open Access Journals (Sweden)

    Richard Mason

    2012-03-01

    Full Text Available Extensive research on the rocks of the Karoo Supergroup has shown that this sequence, which contains an unsurpassed record of Permian–Jurassic tetrapods, records a largely unbroken stratigraphic succession from 300 Ma to 180 Ma. This Gondwanan succession was deposited in a changing environmental setting reflecting glacial marine through deltaic to fluvial and aeolian desert conditions. The contact between the Ecca and Beaufort Groups (at the top of the Waterford Formation of the Ecca Group in the southern and western Karoo represents a change in depositional environment from a subaqueous to a subaerial delta plain. By contrast, the Waterford Formation has not yet been recognised in the south-eastern Karoo Basin, which might imply that a major unconformity is present between the Fort Brown Formation of the Ecca Group, deposited in a prodelta environment, and the overlying fluvially deposited Koonap Formation of the Beaufort Group. From careful documentation of lithofacies and sedimentological data, it can be demonstrated that the Waterford Formation is indeed present in the south-eastern part of the basin and that no major unconformity is present – a fact that has implications for the mapping of Karoo rocks in the Eastern Cape Province of South Africa, for understanding the depositional environment of ’reptilian‘ fossils from the lowermost Beaufort in this part of the Karoo basin, and for basin development models.

  17. Paleogene strata of the Eastern Los Angeles basin, California: Paleogeography and constraints on neogene structural evolution

    Science.gov (United States)

    McCulloh, T.H.; Beyer, L.A.; Enrico, R.J.

    2000-01-01

    Post-Paleogene dextral slip of 8-9 km is demonstrated for the southeastern part of the Whittier fault zone in the eastern Los Angeles basin area of southern California. A linear axis of greatest thickness for the combined upper Paleocene and lower to lower-middle Eocene clastic formations intersects the fault zone and is offset by it to give the new measure. Fragmentary evidence hints that the Whittier structural zone may have exerted control on bathymetric-topographic relief and sedimentation even in latest Paleocene (ca. 54 Ma). A clear topographic influence was exerted by 20-17 Ma. Strike-slip and present deformational style is younger than ca. 8 Ma. Our Paleogene isopach map extends as far west as long 117??58'W and is a foundation for companion zonal maps of predominant lithology and depositional environments. Integration of new palynological data with published biostratigraphic results and both new and published lithologic and sedimentological interpretations support the zonal maps. Reconstruction of marine-nonmarine facies and fragmented basin margins yields a model for the northeastern corner of a Paleogene coastal basin. Palinspastic adjustment for the Neogene-Quaternary Whittier fault offset and a reasoned westerly extension of the northern edge of the basin model yield a reconstruction of Paleogene paleogeography-paleoceanography. Our reconstruction is based partly on the absence of both Paleocene and Eocene deposits beneath the unconformable base of the middle Miocene Topanga Group in a region nowhere less than 15 km wide between the Raymond-Sierra Madre-Cucamonga fault zone and the northern edge of the Paleocene basin. Thus, Paleogene strata of the Santa Monica Mountains could not have been offset from the northern extension of the Santa Ana Mountains by sinistral slip on those boundary faults. Structural rearrangements needed to accommodate the clockwise rotation of the western Transverse Ranges from the early Miocene starting position are thereby

  18. Environmental Setting of the Lower Merced River Basin, California

    Science.gov (United States)

    Gronberg, Jo Ann M.; Kratzer, Charles R.

    2006-01-01

    In 1991, the U.S. Geological Survey began to study the effects of natural and anthropogenic influences on the quality of ground water, surface water, biology, and ecology as part of the National Water-Quality Assessment (NAWQA) Program. As part of this program, the San Joaquin-Tulare Basins study unit is assessing parts of the lower Merced River Basin, California. This report provides descriptions of natural and anthropogenic features of this basin as background information to assess the influence of these and other factors on water quality. The lower Merced River Basin, which encompasses the Mustang Creek Subbasin, gently slopes from the northeast to the southwest toward the San Joaquin River. The arid to semiarid climate is characterized by hot summers (highs of mid 90 degrees Fahrenheit) and mild winters (lows of mid 30 degrees Fahrenheit). Annual precipitation is highly variable, with long periods of drought and above normal precipitation. Population is estimated at about 39,230 for 2000. The watershed is predominately agricultural on the valley floor. Approximately 2.2 million pounds active ingredient of pesticides and an estimated 17.6 million pounds active ingredient of nitrogen and phosphorus fertilizer is applied annually to the agricultural land.

  19. Three-dimensional model of the late Cenozoic history of the Death Valley region, southeastern California

    Science.gov (United States)

    Serpa, Laura; Pavlis, Terry L.

    1996-12-01

    The accumulation of a large database on the timing and kinematics of late Cenozoic deformation in the Death Valley region of southeastern California indicates a complex three-dimensional history. On the basis of paleogeographic reconstructions we suggest the system was initiated as a localized pull-apart between two conjugate strike-slip faults, the Garlock and Furnace Creek faults, and evolved into a system characterized by distributed transtension related to the eastern California shear zone. Our reconstructions differ from previous models in the incorporation of significant vertical axis rotations of a number of crustal blocks to explain paleomagnetic data from the region. The model may resolve (1) a long-standing problem of the eastern termination of the Garlock fault which is explained here as a complex system of splays that initially terminated in the pull-apart between the Furnace Creek and Garlock systems; and (2) the complex architecture of the Black Mountains which is explained here in terms of initial extreme attenuation between the Garlock and Furnace Creek systems with overprinting by a fold and normal fault system that operated simultaneously as a result of distributed transtension. This model suggests much of the displacement field is taken up in rotations and translations, and the actual crustal thinning in our model is relatively small (50-66% of original thickness).

  20. Wildlife habitats in managed rangelands—the Great Basin of southeastern Oregon: plant communities and their importance to wildlife.

    Science.gov (United States)

    J. Edward Dealy; Donavin A. Leckenby; Diane M. Concannon

    1981-01-01

    Plant communities in the Great Basin of southeastern Oregon are described, and a field key is provided. The value of a plant community’s vertical and horizontal structure and the seasonal availability of its forage are examined in relation to wildlife habitat in managed rangelands. Further, the importance of individual and combined plant communities to wildlife in...

  1. Wildlife habitats in managed rangelands—the Great Basin of southeastern Oregon: management practices and options.

    Science.gov (United States)

    Frederick C. Hall

    1985-01-01

    Management practices and options to provide habitat for wildlife in the Great Basin of southeastern Oregon deal with both vegetation treatment and protection, livestock management, maintenance or distribution of water developments, protection of wildlife areas through road closures or fencing, and direct manipulation of wildlife through hunting, trapping, or other...

  2. Gulf of California Rift Structure and Magmatism: Guaymas Basin and Comparison With Southern Basins

    Science.gov (United States)

    Lizarralde, D.; Axen, G. J.; Fletcher, J. M.; Fernandez, A. G.; Harding, A. J.; Holbrook, W. S.; Kent, G. M.; Umhoefer, P. J.; Brown, H.; Paramo, P.; Sutherland, F.

    2005-12-01

    We present a detailed seismic velocity model of the crust from margin to margin across the Guaymas Basin and compare this model with basins in the southern Gulf of California. These results are based on data from a 2002 crustal-scale, active-source seismic experiment, where multi-channel and wide-angle seismic data were acquired along three flow-line transects across Guaymas Basin, Alarcon Basin, and between Puerto Vallarta and Cabo San Lucas. Each of these transects was instrumented with ocean-bottom seismometers spaced 10-15 km apart and similarly spaced seismometers on land recording the offshore shots. The seafloor morphology of the Gulf has suggested to many that the mode of extension transitions from localized extension followed by seafloor spreading (a narrow rift) in the southern Gulf to a wide-rift mode of distributed extension in the north. This is not the case, however. The thickly sedimented Guaymas basin is a narrow rift. Lithospheric necking occurred after ~150 km of extension, and a subsequent ~300 km of extension has been accommodated by the formation of new lithosphere. The spreading center has been robustly magmatic, forming new igneous crust 7 to 10 km thick. To the south, the Alarcon basin is a wider rift, experiencing ~290 km of extension, including rift relocations, prior to the onset of seafloor spreading (~160 km of extension), which produces crust ~6 km thick. Thus, total extension for these two basins is similar (~450 km), but the mode of extension and manifestation of magmatism are very different. Differences in sedimentation may provide an explanation for the variation in magmatism between these basins, with the thicker sediments in the north providing a thermal blanket that enables more complete melt extraction from the mantle. Magmatism does not provide a sufficient explanation for the difference in rift width, however, since rifting between Cabo San Lucas and Puerto Vallarta, just one segment south of Alarcon, was particularly narrow

  3. The nature of the Dakota-Morrison boundary, Southeastern San Juan basin

    International Nuclear Information System (INIS)

    Aubrey, W.M.

    1986-01-01

    A thin, discontinuous, fluvial locally conglomeratic sandstone at the vase of the Dakota Sandstone in the vicinity of the southeastern San Juan basin, New Mexico has been named the Encinal Canyon Member of the Dakota Sandstone. In the past, the sandstone beds, placed here in the Encinal Canyon, have been included in the Jackpile sandstone, (an economic unit in the Morrison Formation), in the Burro Canyon Formation, or in the Oak Canyon Member of the Dakota Sandstone. Distinction between the Encinal Canyon Member and the Jackpile sandstone, which are separated by an unconformity that probably spans most of the Early Cretaceous, is economically important. The Jackpile is a primary uranium exploration target, whereas the Dakota contains little known uranium. In the past, the sub-Dakota erosional surface in the southeastern San Juan basin generally was thought to be at the base of the marine and paralic Oak Canyon Member of the Dakota Sandstone, which overlies the Encinal Canyon Member. The unconformity is shown here to be at the base of the fluvial rocks of the Encinal Canyon Member. Local relief at the base of the Encinal Canyon indicates that the sub-Dakota erosional surface formed during a time of regional degradation. Easterly flowing streams scoured underlying units and in some places cut completely through the Jackpile sandstone and the Burro Canyon Formation. The Encinal Canyon was deposited in response to the initial transgression of the Dakota sea. As the sea inundated the area, a transgressive erosional surface formed, and the overlying paralic and marine sediments of the Oak Canyon Member were deposited

  4. Characteristics of Atmospheric River Families in California's Russian River Basin

    Science.gov (United States)

    Fish, M. A.; Wilson, A. M.; Ralph, F. M.

    2017-12-01

    Previous studies have shown the importance of antecedent conditions and storm duration on atmospheric river (AR) impacts in California's Russian River basin. This study concludes that successive ARs, or families of ARs, produce an enhanced streamflow response compared to individual storms. This amplifies the impacts of these storms, which contribute to 50% of the annual precipitation in the Russian River basin. Using the Modern Era Retrospective - analysis for Research and Applications 2 dataset and 228 AR events from November 2004 - April 2017 affecting Bodega Bay, CA (BBY), this study identified favorable characteristics for families vs single ARs and their associated impacts. It was found that 111 AR events ( 50%) occurred within 5 days of one another with 44 events ( 40%) occurring within 24 hours. Using the winter of 2017, which had a multitude of successive ARs in Northern California, this study evaluates the applicability of family composites using case study comparisons. The results of this study show large divergences of family composites from the overall AR pattern, depending on the time interval between events. A composite of all AR events show Bodega Bay generally south of the jet exit region, SW-NE tilt of 500mb heights and a more northerly subtropical high. ARs occurring on the same day have faster southerly winds, a weaker low off the coast and a southerly moisture plume extending along the CA coast. Comparatively ARs that occur the following day, feature a more zonal pattern with faster winds north of BBY, a deeper low off the coast and a moisture plume southwest of the Russian River watershed.

  5. Shelf-basin Exchange in the Bering Canyon in Southeastern Bering Sea: Role of Unimak Pass

    Science.gov (United States)

    Cheng, W.; Ladd, C. A.; Hermann, A. J.; Stabeno, P. J.

    2016-02-01

    Shelf-basin exchanges in the southeastern Bering Sea have significant implications for primary production on the Bering Sea shelf; yet, the mechanisms controlling such exchange are not well understood. One area with potentially enhanced cross-shelf transport is the Bering Canyon, where flow through the relatively shallow Unimak Pass meets and interacts with the Aleutian North Slope Current (ANSC). As a result, the ocean circulation and water properties in the area are influenced by local as well as remote wind forcing, ocean bathymetry, tides, and exhibit high spatial and temporal variability on multiple scales. In this study, we use ocean in situ measurement and numerical modeling to examine processes influencing shelf-basin exchange in the Bering Canyon. Results thus far suggest that on seasonal and longer time scales, the onshore flow across the Bering Canyon left rim is influenced by the Unimak pass transport, and to a lesser extent by the transport associated with the ANSC. Both Unimak Pass transport and ANSC transport are highly correlated with the along-shore wind stress south of the Aleutian Island Chain, but the Unimak Pass transport responds faster to the along-shore wind forcing by a month. These results highlight the importance of Unimak Pass in influencing the regional circulation and on-shelf transport. Numerical experimentation will be used to further elucidate the effects of tidal mixing and advection associated with Unimak Pass.

  6. Paleobiogeography of the Onondaga Limestone in southeastern New York: A second shelf to basin ramp

    Energy Technology Data Exchange (ETDEWEB)

    Lindemann, R.H. (Skidmore Coll., Saratoga Springs, NY (United States). Dept. of Geology); Feldman, H.R. (Touro Coll., New York, NY (United States). Biology Dept.)

    1993-03-01

    As a logical consequence of outcrop pattern and density, research on the Middle Devonian Onondaga Limestone has concentrated on the formation in an essentially east-west transect between the mid-Hudson Valley and Buffalo. Paleogeographic analysis reveals a symmetrical pattern, with the axis of the Appalachian Basin in central New York and the Edgecliff reefs flourishing in the eastern and western shelf regions. The subsurface reef trend of western New York and Pennsylvania is consistent with this model and is suggestive of a parallel reef trend in the east. However, recent examination of the formation in the southeastern part of the state has led to a pronounced reinterpretation of Onondaga paleobiogeography in that area. The authors have determined that there was a shallow carbonate shelf in the Helderberg-Coxsackie areas, a thick accumulation of shelf-margin bryozoan bafflestone between Leeds and Saugerties, and an even thicker accumulation of sparse to packed biocalcisiltites deposited on a carbonate ramp dipping southward into the Port Jervis area. It appears that this ramp occupied the northern margin of a structural base depocenter, located to the east of and not directly related to the topographic basin of central New York, which was centered in the Tristates vicinity from the Late Silurian until the early Middle Devonian.

  7. New permian fusulinids from conglomerate mesa, southeastern inyo Mountains, east-central california

    Science.gov (United States)

    Stevens, C.H.; Stone, P.

    2009-01-01

    In the Conglomerate Mesa area in the southeastern Inyo Mountains, east-central California, a series of distinctive fusulinid assemblages ranging in age from late Artinskian to Kungurian or Roadian was developed in units 7-10 of the sedimentary rocks of Santa Rosa Flat (part of the Owens Valley Group). The fauna of unit 7 shows some eastern Klamath Mountains affinity, but most of the species in unit 7 and the lower half of unit 8 are highly endemic and comprise three new genera with 12 new species, two unusual unassigned forms, and two other new species assigned to previously described genera. New taxa include: Crenulosepta new genus with five new species, C. inyoensis, C. delicata, C. fusiformis, C. rossi, and C. wahlmani; Nigribaccinus new genus with three new species, N. giganteus, N. elegans, and N. ? nestelli; and the new genus Inyoschwagerina with four new species, I. magnified, I. elayeri, I. elongata, and I.? linderae. Cuniculinella Skinner and Wilde, 1965, is represented by one new species, C. parva, and Skinnerella Coogan, 1960 by one new species, S.? mcallisteri. Faunas from the upper half of unit 8, unit 9, and unit 10 have a strong West Texas affinity. New species from these units are Skinnerella davydovi, S. hexagona, Parafusulina cerrogordoensis, P. complexa, P. halli, P. owensensis, and P. ubehebensis. Copyright ?? 2009, The Paleontological Society.

  8. Imaging the magmatic system of Mono Basin, California with magnetotellurics in three--dimensions

    Science.gov (United States)

    Peacock, Jared R.; Mangan, Margaret T.; McPhee, Darcy K.; Ponce, David A.

    2015-01-01

    A three–dimensional (3D) electrical resistivity model of Mono Basin in eastern California unveils a complex subsurface filled with zones of partial melt, fluid–filled fracture networks, cold plutons, and regional faults. In 2013, 62 broadband magnetotelluric (MT) stations were collected in an array around southeastern Mono Basin from which a 3D electrical resistivity model was created with a resolvable depth of 35 km. Multiple robust electrical resistivity features were found that correlate with existing geophysical observations. The most robust features are two 300 ± 50 km3 near-vertical conductive bodies (3–10 Ω·m) that underlie the southeast and north-eastern margin of Mono Craters below 10 km depth. These features are interpreted as magmatic crystal–melt mush zones of 15 ± 5% interstitial melt surrounded by hydrothermal fluids and are likely sources for Holocene eruptions. Two conductive east–dipping structures appear to connect each magma source region to the surface. A conductive arc–like structure (resistivity (200 Ω·m) suggestive of a cooled connection. A third, less constrained conductive feature (4–10 Ω·m) 15 km deep extending to 35 km is located west of Mono Craters near the eastern front of the Sierra Nevada escarpment, and is coincident with a zone of sporadic, long–period earthquakes that are characteristic of a fluid-filled (magmatic or metamorphic) fracture network. A resistive feature (103–105 Ω·m) located under Aeolian Buttes contains a deep root down to 25 km. The eastern edge of this resistor appears to structurally control the arcuate shape of Mono Craters. These observations have been combined to form a new conceptual model of the magmatic system beneath Mono Craters to a depth of 30 km.

  9. Coccolithophore export production in Guaymas Basin, Gulf of California: Response to climate forcing.

    NARCIS (Netherlands)

    Ziveri, P.; Thunell, R.

    2000-01-01

    The flux and taxonomic composition of coccolithophores has been determined for sediment trap samples collected over a two-year period from Guaymas Basin, central Gulf of California. The Gulf of California is a subtropical marginal sea with exceptionally high rates of primary productivity. The annual

  10. A water system model for exploring electric energy alternatives in southeastern US basins

    International Nuclear Information System (INIS)

    Flores-López, F; Yates, D

    2013-01-01

    Electric power generation often involves the use of water for power plant cooling and steam generation, which typically involves the release of cooling water to nearby rivers and lakes. The resulting thermal pollution may negatively impact the ecosystems of these water bodies. Water resource systems models enable the examination of the implications of alternative electric generation on regional water resources. This letter documents the development, calibration, and validation of a climate-driven water resource systems model of the Apalachicola–Chattahoochee–Flint, the Alabama–Coosa–Tallapoosa, and the Tombigbee River basins in the states of Georgia, Alabama, and Florida, in the southeastern US. The model represents different water users, including power plants, agricultural water users, and municipal users. The model takes into account local population, per-capita use estimates, and changes in population growth. The water resources planning model was calibrated and validated against the observed, managed flows through the river systems of the three basins. Flow calibration was performed on land cover, water capacity, and hydraulic conductivity of soil horizons; river water temperature calibration was performed on channel width and slope properties. Goodness-of-fit statistics indicate that under 1980–2010 levels of water use, the model robustly represents major features of monthly average streamflow and water temperatures. The application of this integrated electricity generation–water resources planning model can be used to explore alternative electric generation and water implications. The implementation of this model is explored in the companion paper of this focus issue (Yates et al 2013 Environ. Res. Lett. 8 035042). (letter)

  11. Response surfaces of vulnerability to climate change: The Colorado River Basin, the High Plains, and California

    Science.gov (United States)

    Romano Foti; Jorge A. Ramirez; Thomas C. Brown

    2014-01-01

    We quantify the vulnerability of water supply to shortage for the Colorado River Basin and basins of the High Plains and California and assess the sensitivity of their water supply system to future changes in the statistical variability of supply and demand. We do so for current conditions and future socio-economic scenarios within a probabilistic framework that...

  12. 76 FR 17347 - Revision to the California State Implementation Plan, Great Basin Unified Air Pollution Control...

    Science.gov (United States)

    2011-03-29

    ...) * * * (D) Great Basin Unified Air Pollution Control District (1) Rule 201, ``Exemptions,'' adopted on... AGENCY 40 CFR Part 52 Revision to the California State Implementation Plan, Great Basin Unified Air Pollution Control District CFR Correction In Title 40 of the Code of Federal Regulations, Part 52 (Sec. Sec...

  13. Plate interior polyphase fault systems and sedimentary basin evolution: A case study of the East Gobi Basin and East Gobi Fault Zone, southeastern Mongolia

    Science.gov (United States)

    Heumann, Matthew J.; Johnson, Cari L.; Webb, Laura E.

    2018-01-01

    Structural interpretation of 2-D seismic reflection data and subsurface-outcrop correlations reveal six distinct phases of deformation recorded in the Paleozoic basement rocks and Mesozoic-Cenozoic basin fill of the East Gobi Basin (EGB), southeastern Mongolia. These phases include arc accretion and arc-continent collision in late Paleozoic time, Late Triassic sinistral shear-zone development, Early Jurassic fold and thrust belt style shortening, Middle Jurassic-Lower Cretaceous extension and rift basin development, middle Cretaceous shortening with basin inversion and regional unconformity development, and Late Cretaceous-Oligocene thermal subsidence with renewed Paleogene left-lateral strike slip faulting across the fault zone. The five post-amalgamation deformation phases are localized along the East Gobi Fault Zone, suggesting that preexisting structures and boundary conditions exert fundamental controls on the long term evolution of intracontinental basins such as the EGB. Subsurface geophysical data and outcrop correlations demonstrate that the main subbasins of the EGB contain major differences in basement metamorphic and structural fabrics, basin fill patterns, and distinct Mesozoic-Cenozoic fault generations. Potential causes related to far-field boundary conditions and other driving factors are suggested for each of the major deformation phases.

  14. Variation of Annual ET Determined from Water Budgets Across Rural Southeastern Basins Differing in Forest Types

    Science.gov (United States)

    Younger, S. E.; Jackson, C. R.

    2017-12-01

    In the Southeastern United States, evapotranspiration (ET) typically accounts for 60-70% of precipitation. Watershed and plot scale experiments show that evergreen forests have higher ET rates than hardwood forests and pastures. However, some plot experiments indicate that certain hardwood species have higher ET than paired evergreens. The complexity of factors influencing ET in mixed land cover watersheds makes identifying the relative influences difficult. Previous watershed scale studies have relied on regression to understand the influences or low flow analysis to indicate growing season differences among watersheds. Existing studies in the southeast investigating ET rates for watersheds with multiple forest cover types have failed to identify a significant forest type effect, but these studies acknowledge small sample sizes. Trends of decreasing streamflow have been recognized in the region and are generally attributed to five key factors, 1.) influences from multiple droughts, 2.) changes in distribution of precipitation, 3.) reforestation of agricultural land, 4.) increasing consumptive uses, or 5.) a combination of these and other factors. This study attempts to address the influence of forest type on long term average annual streamflow and on stream low flows. Long term annual ET rates were calculated as ET = P-Q for 46 USGS gaged basins with daily data for the 1982 - 2014 water years, >40% forest cover, and no large reservoirs. Land cover data was regressed against ET to describe the relationship between each of the forest types in the National Land Cover Database. Regression analysis indicates evergreen land cover has a positive relationship with ET while deciduous and total forest have a negative relationship with ET. Low flow analysis indicates low flows tend to be lower in watersheds with more evergreen cover, and that low flows increase with increasing deciduous cover, although these relationships are noisy. This work suggests considering forest

  15. Fish fauna from Sapucaí-Mirim River, tributary of Grande River, upper Paraná River basin, Southeastern Brazil

    OpenAIRE

    Oliveira,Alexandre Kannebley de; Garavello,Julio Cesar; Cesario,Vinicius Vendramini; Cardoso,Rodrigo Torres

    2016-01-01

    The fish species composition of Sapucaí-Mirim River is herein reported and discussed in the faunistic context of Grande and Paranaíba river basins, both formers of the Paraná River. The Sapucaí-Mirim is an important tributary of this hydrographic system, flowing to the left bank of Grande River in a region occupied by the reservoir of the Porto Colombia hydroelectric power plant, at São Paulo state northeastern region, in southeastern Brazil. The poorly known fish diversity of the Sapucaí-Mir...

  16. Tectonoestratigraphic and Thermal Models of the Tiburon and Wagner Basins, northern Gulf of California Rift System

    Science.gov (United States)

    Contreras, J.; Ramirez Zerpa, N. A.; Negrete-Aranda, R.

    2014-12-01

    The northern Gulf of California Rift System consist sofa series faults that accommodate both normal and strike-slip motion. The faults formed a series of half-greens filled with more than 7 km of siliciclastic suc­cessions. Here, we present tectonostratigraphic and heat flow models for the Tiburón basin, in the southern part of the system, and the Wag­ner basin in the north. The models are constrained by two-dimensional seis­mic lines and by two deep boreholes drilled by PEMEX­-PEP. Analysis of the seismic lines and models' results show that: (i) subsidence of the basins is controlled by high-angle normal faults and by flow of the lower crust, (ii) basins share a common history, and (iii) there are significant differences in the way brittle strain was partitioned in the basins, a feature frequently observed in rift basins. On one hand, the bounding faults of the Tiburón basin have a nested geometry and became active following a west-to-east sequence of activation. The Tiburon half-graben was formed by two pulses of fault activity. One took place during the protogulf extensional phase in the Miocene and the other during the opening of Gulf of California in the Pleistocene. On the other hand, the Wagner basin is the result of two fault generations. During the late-to middle Miocene, the west-dipping Cerro Prieto and San Felipe faults formed a domino array. Then, during the Pleistocene the Consag and Wagner faults dissected the hanging-wall of the Cerro Prieto fault forming the modern Wagner basin. Thermal modeling of the deep borehole temperatures suggests that the heat flow in these basins in the order of 110 mW/m2 which is in agreement with superficial heat flow measurements in the northern Gulf of California Rift System.

  17. Geothermal systems of the Mono Basin-Long Valley region, eastern California and western Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Higgins, C.T.; Flynn, T.; Chapman, R.H.; Trexler, D.T.; Chase, G.R.; Bacon, C.F.; Ghusn, G. Jr.

    1985-01-01

    The region that includes Mono Basin, Long Valley, the Bridgeport-Bodie Hills area, and Aurora, in eastern California and western Nevada was studied to determine the possible causes and interactions of the geothermal anomalies in the Mono Basin-Long Valley region as a whole. A special goal of the study was to locate possible shallow bodies of magma and to determine their influence on the hydrothermal systems in the region. (ACR)

  18. Controls on large landslide distribution in the southeastern interior Columbia River basin

    Science.gov (United States)

    Safran, E. B.; Anderson, S. W.; Ely, L.; House, P. K.; O'Connor, J. E.; Grant, G.; Beebee, R. A.; Fenton, C.; Brossy, C. C.

    2006-12-01

    Valley-wall landslides episodically deliver large caliber material to channels and sometimes dam rivers entirely, creating potential for high-magnitude outburst floods. These episodic events have persistent impacts on local channel morphology and may affect broader-scale bedrock incision patterns, especially in semi-arid, relatively low-gradient environments where meteorologically generated floods only infrequently mobilize large, landslide- delivered boulders. A first step in evaluating the influence of large landslides on channel incision processes is to map and understand their spatial distribution. We mapped approximately 300 landslides or landslide complexes ranging in area from 0.1 to 40 km2 in the uplifted volcanic plateaus of the southeastern interior Columbia River basin, primarily in central and eastern Oregon. Anecdotal reports and/or analyses of individual landslides in the region suggest that exposures of key contacts between dense, coherent rock and weak underlying materials exert a dominant control on landslide occurrence. We performed a suite of spatial analyses to test this hypothesis. Our analyses reveal that 82% of landslides mapped contain at least one combination of coherent and weak rocktypes. In 85% of these, the coherent unit(s) cap the weak unit(s). Overall, the fractional area of terrain involved in a landslide within a 1 km buffer of all coherent-weak unit contacts is relatively small: about 1%. Local relief is an important secondary control on landslide occurrence. Of all terrain supporting >200 m local relief, about 2% by area is involved in landslides. This figure is 200 m of local relief but >1 km from key contacts and approximately 4% for areas supporting >200 m of local relief within 1 km of key contacts. Several key contacts between coherent and weak rock exist throughout the study region; we have identified those most conducive to landsliding per unit length of contact. On average, valley walls involved in landslides have slopes

  19. Shale Gas Content Calculation of the Triassic Yanchang Formation in the Southeastern Ordos Basin, China

    Directory of Open Access Journals (Sweden)

    Jiao Su

    2017-11-01

    Full Text Available Shale gas content is the key parameter for shale gas potential evaluation and favorable area prediction. Therefore, it is very important to determine shale gas content accurately. Generally, we use the US Bureau of Mines (USBM method for coal reservoirs to calculate the gas content of shale reservoirs. However, shale reservoirs are different from coal reservoirs in depth, pressure, core collection, etc. This method would inevitably cause problems. In order to make the USBM method more suitable for shale reservoirs, an improved USBM method is put forward on the basis of systematic analysis of core pressure history and temperature history during shale gas degassing. The improved USBM method modifies the calculation method of the gas loss time, and determines the temperature balance time of water heating. In addition, we give the calculation method of adsorption gas content and free gas content, especially the new method of calculating the oil dissolved gas content and water dissolved gas content that are easily neglected. We used the direct method (USBM and the improved USBM and the indirect method (including the calculation of adsorption gas, free gas and the dissolved gas method to calculate the shale gas content of 16 shale samples of the Triassic Yanchang Formation in the Southeastern Ordos Basin, China. The results of the improved USBM method show that the total shale gas content is high, with an average of 3.97 m3/t, and the lost shale gas content is the largest proportion with an average of 62%. The total shale gas content calculated by the improved USBM method is greater than that of the USBM method. The results of the indirect method show that the total shale gas content is large, with an average of 4.11 m3/t, and the adsorption shale gas content is the largest proportion with an average of 71%. The oil dissolved shale gas content which should be paid attention to accounts for about 7.8%. The discrepancy between the direct method and

  20. Status of groundwater quality in the Coastal Los Angeles Basin, 2006-California GAMA Priority Basin Project

    Science.gov (United States)

    Goldrath, Dara; Fram, Miranda S.; Land, Michael; Belitz, Kenneth

    2012-01-01

    Groundwater quality in the approximately 860-square-mile (2,227-square-kilometer) Coastal Los Angeles Basin study unit (CLAB) was investigated as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study area is located in southern California in Los Angeles and Orange Counties. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory. The GAMA CLAB study was designed to provide a spatially unbiased assessment of the quality of untreated (raw) groundwater in the primary aquifer system. The assessment is based on water-quality and ancillary data collected in 2006 by the USGS from 69 wells and on water-quality data from the California Department of Public Health (CDPH) database. The primary aquifer system was defined by the depth interval of the wells listed in the CDPH database for the CLAB study unit. The quality of groundwater in the primary aquifer system may be different from that in the shallower or deeper water-bearing zones; shallow groundwater may be more vulnerable to surficial contamination. This study assesses the status of the current quality of the groundwater resource by using data from samples analyzed for volatile organic compounds (VOCs), pesticides, and naturally occurring inorganic constituents, such as major ions and trace elements. This status assessment is intended to characterize the quality of groundwater resources in the primary aquifer system of the CLAB study unit, not the treated drinking water delivered to consumers by water purveyors. Relative-concentrations (sample concentration divided by the health- or aesthetic-based benchmark concentration) were used for evaluating groundwater quality for those constituents that have Federal and (or) California regulatory or non-regulatory benchmarks for drinking-water quality. A relative

  1. 2D Seismic Velocity Modelling in the Southeastern Romanian Carpathians and its Foreland (Vrancea Zone and Focsani Basin)

    Science.gov (United States)

    Stephenson, R.; Bocin, A.; Tryggvason, A.

    2003-12-01

    The DACIA-PLAN (Danube and Carpathian Integrated Action on Processes in the Lithosphere and Neotectonics) deep seismic reflection survey was performed in August-September 2001, with the objective of obtaining of new information on the deep structure of the external Carpathians nappes and the architecture of Tertiary/Quaternary basins developed within and adjacent to the seismically-active Vrancea Zone, including the rapidly subsiding Focsani Basin. The DACIA-PLAN profile is about 140 km long, having a roughly NW-SE direction, from near the southeast Transylvanian Basin, across the mountainous southeastern Carpathians and their foreland to near the Danube Dalta. A high resolution 2D velocity model of the upper crust along the seismic profile has been determined from a first-arrival tomographic inversion of the DACIA-PLAN data. The shallowing of Palaeozoic-Mesozoic basement, and related structural heterogeneity within it, beneath the eastern flank of the Focsani Basin is clearly seen. Velocity heterogeneity within the Carpathian nappe belt is also evident and is indicative of internal structural complexity, including the presence of salt bodies and basement involvement in thrusting, thus favouring some current geological models over others. The presence of basement involvement implies the compressional reactivation of pre-existing basement normal faults. Members of the DACIA-PLAN/TomoSeis Working Group (see poster) should be considered as co-authors of this presentation.

  2. Remaining recoverable petroleum in giant oil fields of the Los Angeles Basin, southern California

    Science.gov (United States)

    Gautier, Donald L.; Tennyson, Marilyn E.; Cook, Troy A.; Charpentier, Ronald R.; Klett, Timothy R.

    2012-01-01

    Using a probabilistic geology-based methodology, a team of U.S. Geological Survey (USGS) scientists recently assessed the remaining recoverable oil in 10 oil fields of the Los Angeles Basin in southern California. The results of the assessment suggest that between 1.4 and 5.6 billion barrels of additional oil could be recovered from those fields with existing technology.

  3. Fully Integrated Atmospheric, Surface, and Subsurface Model of the California Basin

    Science.gov (United States)

    Davison, J. H.; Hwang, H. T.; Sudicky, E. A.; Mallia, D. V.; Lin, J. C.

    2016-12-01

    The recent drought in the Western United States has crippled agriculture in California's Central Valley. Farmers, facing reduced surface water flow, have turned to groundwater as their primary solution to the water crisis. However, the unsustainable pumping rates seen throughout California have drastically decreased the surface and subsurface water levels. For this reason, we developed a coupled subsurface, surface, and atmospheric model for the entire California Basin that captures the feedbacks between the three domains at an extremely high spatial and temporal resolution. Our coupled model framework integrates HydroGeoSphere (HGS), a fully implicit three-dimensional control-volume finite element surface and variably saturated subsurface model with evapotranspiration process, to Weather Research and Forecasting (WRF), a three-dimensional mesoscale nonhydrostatic atmospheric model. HGS replaces the land surface component within WRF, and provides WRF with the actual evapotranspiration (AET) and soil saturation. In return, WRF provides HGS with the potential evapotranspiration (PET) and precipitation fluxes. The flexible coupling technique allows HGS and WRF to have unique meshing and projection characteristics and links the domains based on their geographic coordinates (i.e., latitude and longitude). The California Basin model successfully simulated similar drawdown rates to the Gravity Recovery and Climate Experiment (GRACE) and replicated the Klamath and Sacramento River hydrographs. Furthermore, our simulation results reproduced field measured precipitation and evapotranspiration. Currently, our coupled California Basin model is the most complete water resource simulator because we combine the surface, subsurface, and atmosphere into a single domain.

  4. Water resources inventory of Connecticut Part 3: lower Thames and southeastern coastal river basins

    Science.gov (United States)

    Thomas, Chester E.; Cervione, Michael A.; Grossman, I.G.

    1968-01-01

    The lower Thames and southeastern coastal river basins have a relatively abundant supply of water of generally good quality which is derived from streams entering the area and precipitation that has fallen on the area. Annual precipitation has ranged from about 32 inches to 65 inches and has averaged about 48 inches over a 30-year period. Approximately 22 inches of water are returned to the atmosphere each year by evaporation and transpiration; the remainder of the annual precipitation either flows overland to streams or percolates downward to the water table and ultimately flows out of the report area through estuaries and coastal streams or as underflow through the deposits beneath. During the autumn and winter months precipitation normally is sufficient to cause a substantial increase in the amount of water stored underground and in surface reservoirs within the report area, whereas in the summer most of the precipitation is lost through evaporation and transpiration, resulting in sharply reduced stream-flow and lowered ground-water levels. The mean monthly storage of water on an average is about 3.8 inches higher in November than it is in June. The amount of water that flows through and out of the report area represents the total amount of water potentially available for use by man. For the 30-year period 1931 through 1960, the annual runoff from the report area has averaged nearly 26 inches (200 billion gallons), from the entire Thames River basin above Norwich about 24 inches (530 billion gallons), and from the Pawcatuck River basin about 26 inches (130 billion gallons). A total average annual runoff of 860 billion gallons is therefore available. Although runoff indicates the total amount of water potentially available, it is usually not economically feasible for man to use all of it. On the other hand, with increased development, it is possible that some water will be reused several times. The water available may be tapped as it flows through the area or is

  5. Wildlife habitats in managed rangelands—the Great Basin of southeastern Oregon: the relationship of terrestrial vertebrates to plant communities and structural conditions (Part 2).

    Science.gov (United States)

    Chris Maser; Jack Ward Thomas; Ralph G. Anderson

    1984-01-01

    The relationships of terrestrial vertebrates to plant communities, structural conditions, and special habitats in the Great Basin of southeastern Oregon are described in a series of appendices. The importance of habitat components to wildlife and the predictability of management activities on wildlife are examined in terms of managed rangelands. ...

  6. Wildlife habitats in managed rangelands—the Great Basin of southeastern Oregon: the relationship of terrestrial vertebrates to plant communities and structural conditions (Part 1).

    Science.gov (United States)

    Chris Maser; Jack Ward Thomas; Ralph G. Anderson

    1984-01-01

    The relationships of terrestrial vertebrates to plant communities, structural conditions, and special habitats in the Great Basin of southeastern Oregon are described. The importance of habitat components to wildlife and the predictability of management activities on wildlife are examined in terms of managed rangelands. The paper does not provide guidelines but rather...

  7. Wildlife habitats in managed rangelands—the Great Basin of southeastern Oregon: native trout.

    Science.gov (United States)

    Wayne Bowers; Bill Hosford; Art Oakley; Carl. Bond

    1979-01-01

    Southeastern Oregon has a variety of fish habitats which include major rivers, tributary streams, large and small reservoirs, lakes, and springs. These habitats are directly related to and highly dependent on the conditions of the surrounding rangeland watersheds. Satterlund (1975, p. 22) put it this way: "Rangelands may yield little water, but they are second...

  8. Structural characteristics of an active fold-and-thrust system in the southeastern Atacama Basin, northern Chile

    Science.gov (United States)

    Lin, Yen-Sheng; Chuang, Yi-Rung; Shyu, J. Bruce H.; González, Gabriel; Shen, Chuan-Chou; Lo, Ching-Hua; Liou, Ya-Hsuan

    2016-08-01

    The western South American margin is one of the most active plate boundaries in the world. Using various remote sensing data sets, we mapped the neotectonic characteristics of an area at the southeastern corner of the Atacama Basin, northern Chile, in the Andean forearc. There, one major N-S trending ridge is clearly visible both in the satellite images and in the field. This ridge reaches 250 m above the basin floor in its middle part and is asymmetrical, with a steep eastern slope and a much gentler western slope. The geometry of the ridge indicates that it formed as an asymmetrical anticline. This anticline is likely formed as a shear fault-bend fold, with a major décollement at a depth of about 2.5 km in the Naranja Formation. We suggest that this décollement is a major structure of the Atacama Basin area. From the ages of the ignimbrites and lake deposits that were deformed by this anticline, we obtained a long-term shortening rate of the major underlying structure at about 0.2 mm/yr. This thin-skinned fold-and-thrust system appears to be active since at least about 3 Ma, and could be as long as since middle Miocene. Therefore, crustal structures may play important roles in the Neogene development of the western Andean margin.

  9. Mechanical Erosion in a Tropical River Basin in Southeastern Brazil: Chemical Characteristics and Annual Fluvial Transport Mechanisms

    Directory of Open Access Journals (Sweden)

    Alexandre Martins Fernandes

    2012-01-01

    Full Text Available This study aims to evaluate the mechanical erosion processes that occur in a tropical river basin, located in the São Paulo state, southeastern Brazil, through the chemical characterization of fine suspended sediments and the transport mechanisms near the river mouth, from March 2009 to September 2010. The chemical characterization indicated the predominance of SiO2, Al2O3, and Fe2O3 and showed no significant seasonal influences on the major element concentrations, expressed as oxides. The concentration variations observed were related to the mobility of chemical species. The evaluation of the rock-alteration degree indicated that the physical weathering was intense in the drainage basin. The fine suspended sediments charge was influenced by the variation discharges throughout the study period. The solid charge estimate of the surface runoff discharge was four times higher in the rainy season than the dry season. The transport of fine suspended sediments at the Sorocaba River mouth was 55.70 t km−2 a−1, corresponding to a specific physical degradation of 37.88 m Ma−1, a value associated with the mechanical erosion rate that corresponds to the soil thickness reduction in the drainage basin.

  10. Geodetic measurement of deformation in the Ventura basin region, southern California

    Science.gov (United States)

    Donnellan, Andrea; Hager, Bradford H.; King, Robert W.; Herring, Thomas A.

    1993-12-01

    We have measured the deformation in the Ventura basin region, southern California, with Global Positioning System (GPS) measurements carried out over 4.6 years between 1987 and 1992. The deformation within our network is spatically variable on scales of tens of kilometers, with strain rates reaching 0.6 +/- 1 micro-rad/yr in the east-central basin. Blocklike rotations are observed south and northwest of the basin where the maximum shear strain rates are an order of magnitude lower (0.06 +/- 1 micro-rad/yr to the south). We also observed clockwise rotations of 1 deg - 7 deg/m.y. Shear strain rates determined by comparing angle changes from historical triangulation spanning several decades and GPS measurements give consistent, though less precise, results. The geodetic rates of shortening across the basin and Western Transverse Ranges are lower than those estimated from geological observations, but the patterns of deformation from the two methods agree qualitatively.

  11. Geophysical Surveys of the Hydrologic Basin Underlying Yosemite Valley, California.

    Science.gov (United States)

    Maher, E. L.; Shaw, K. A.; Carey, C.; Dunn, M. E.; Whitman, S.; Bourdeau, J.; Eckert, E.; Louie, J. N.; Stock, G. M.

    2017-12-01

    UNR students in an Applied Geophysics course conducted geophysical investigations in Yosemite Valley during the months of March and August 2017. The goal of the study is to understand better the depth to bedrock, the geometry of the bedrock basin, and the properties of stratigraphy- below the valley floor. Gutenberg and others published the only prior geophysical investigation in 1956, to constrain the depth to bedrock. We employed gravity, resistivity, and refraction microtremor(ReMi) methods to investigate the interface between valley fill and bedrock, as well as shallow contrasts. Resistivity and ReMi arrays along three north-south transects investigated the top 50-60m of the basin fill. Gravity results constrained by shallow measurements suggest a maximum depth of 1000 m to bedrock. ReMi and resistivity techniques identified shallow contrasts in shear velocity and electrical resistivity that yielded information about the location of the unconfined water table, the thickness of the soil zone, and spatial variation in shallow sediment composition. The upper several meters of sediment commonly showed shear velocities below 200 m/s, while biomass-rich areas and sandy river banks could be below 150 m/s. Vs30 values consistently increased towards the edge of the basin. The general pattern for resistivity profiles was a zone of relatively high resistivity, >100 ohm-m, in the top 4 meters, followed by one or more layers with decreased resistivity. According to gravity measurements, assuming either -0.5 g/cc or -0.7 g/cc density contrast between bedrock and basin sediments, a maximum depth to bedrock is found south of El Capitan at respectively, 1145 ± 215 m or 818 ± 150 m. Longitudinal basin geometry coincides with the basin depth geometry discussed by Gutenberg in 1956. Their results describe a "double camel" shape where the deepest points are near El Capitan and the Ahwahnee Hotel and is shallowest near Yosemite Falls, in a wider part of the valley. An August Deep

  12. 78 FR 39548 - Grapes Grown in Designated Area of Southeastern California; Increased Assessment Rate

    Science.gov (United States)

    2013-07-02

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF AGRICULTURE..., as amended (7 U.S.C. 601- 674), hereinafter referred to as the ``Act.'' The Department of Agriculture... California. They are familiar with the Committee's needs and with the costs for goods and services in their...

  13. Arsenic, Boron, and Fluoride Concentrations in Ground Water in and Near Diabase Intrusions, Newark Basin, Southeastern Pennsylvania

    Science.gov (United States)

    Senior, Lisa A.; Sloto, Ronald A.

    2006-01-01

    During an investigation in 2000 by the U.S. Environmental Protection Agency (USEPA) of possible contaminant releases from an industrial facility on Congo Road near Gilbertsville in Berks and Montgomery Counties, southeastern Pennsylvania, concentrations of arsenic and fluoride above USEPA drinking-water standards of 10 ?g/L and 4 mg/L, respectively, and of boron above the USEPA health advisory level of 600 ?g/L were measured in ground water in an area along the northwestern edge of the Newark Basin. In 2003, the USEPA requested technical assistance from the U.S. Geological Survey (USGS) to help identify sources of arsenic, boron, and fluoride in the ground water in the Congo Road area, which included possible anthropogenic releases and naturally occurring mineralization in the local bedrock aquifer, and to identify other areas in the Newark Basin of southeastern Pennsylvania with similarly elevated concentrations of these constituents. The USGS reviewed available data and collected additional ground-water samples in the Congo Road area and four similar hydrogeologic settings. The Newark Basin is the largest of the 13 major exposed Mesozoic rift basins that stretch from Nova Scotia to South Carolina. Rocks in the Newark Basin include Triassic through Jurassic-age sedimentary sequences of sandstones and shales that were intruded by diabase. Mineral deposits of hydrothermal origin are associated with alteration zones bordering intrusions of diabase and also occur as strata-bound replacement deposits of copper and zinc in sedimentary rocks. The USGS review of data available in 2003 showed that water from about 10 percent of wells throughout the Newark Basin of southeastern Pennsylvania had concentrations of arsenic greater than the USEPA maximum contaminant level (MCL) of 10 ?g/L; the highest reported arsenic concentration was at about 70 ?g/L. Few data on boron were available, and the highest reported boron concentration in well-water samples was 60 ?g/L in contrast

  14. Wildlife habitats in managed rangelands—the Great Basin of southeastern Oregon: manmade habitats.

    Science.gov (United States)

    Chris Maser; Jack Ward Thomas; Ira David Luman; Ralph. Anderson

    1979-01-01

    Manmade structures on rangelands provide specialized habitats for some species. These habitats and how they function as specialized habitat features are examined in this publication. The relationships of the wildlife of the Great Basin to such structures are detailed.

  15. Swatara Creek basin of southeastern Pennsylvania--An evaluation of its hydrologic system

    Science.gov (United States)

    Stuart, Wilbur Tennant; Schneider, William J.; Crooks, James W.

    1967-01-01

    Local concentrations of population in the Swatara Creek basin of Pennsylvania find it necessary to store, transport, and treat water because local supplies are either deficient or have been contaminated by disposal of wastes in upstream areas. Water in the basin is available for the deficient areas and for dilution of the coal-mine drainage in the northern parts and the sewage wastes in the southern parts.

  16. PECTINIDS AND OYSTERS FROM THE PLIOCENE LORETO BASIN (BAJA CALIFORNIA SUR, MEXICO)

    OpenAIRE

    PIAZZA, MICHELE; ROBBA, ELIO

    2017-01-01

    Fourteen pectinid and oyster species from the Pliocene Loreto Basin (Baja California Sur, Mexico) are recorded and discussed with regard to their relationships with closely related taxa. The whole assemblage points toward a Pliocene age. Aequipecten dallasi and Argopecten abietis abietis resulted to be the most useful biostratigraphic taxa, being restricted to Pliocene. The bulk of the considered species were confined within southern regions during the Pliocene. Crassostrea californica osunai...

  17. AUTOCHTHONOUS BIOFACIES IN THE PLIOCENE LORETO BASIN, BAJA CALIFORNIA SUR, MEXICO

    OpenAIRE

    PIAZZA, MICHELE; ROBBA, ELIO

    1998-01-01

    The present paper examines the molluscan and/or echinoid assemblages recovered from two lithostratigraphic units (Piedras Rodadas Sandstone and Arroyo de Arce Norte Sandstone) outcropping in the Pliocene Loreto Basin, Baja California Sur, Mexico. Ten biofacies have been identified, i.e. Trachycardium procerum-Trachycardium senticosum Biofacies, Chione compta-Transennella modesta Biofacies, Laevicardium elenense-Chione kelletii Biofacies, Xenophora sp. 1-Strombus subgracilior Biofacies, Crasso...

  18. Feeding habits of dolphinfish (Coryphaena hippurus) in the southeastern Gulf of California, Mexico

    OpenAIRE

    Tripp Valdez, Arturo; Galvan Magaña, Felipe; Ortega García, Sofía

    2010-01-01

    The objective of the study was to identify key elements of the feeding ecology of the dolphinfish, which is a high tropic predator important for sport and artisanal fishing in the Mexican Pacific. Feeding habits were investigated during the years 2000–2003. This species is seasonal in the southern Gulf of California and probably remains there because of the abundant prey. The contents of 232 dolphinfish stomachs were analyzed, identifying 98 prey species, although only eight of these were wel...

  19. Stratigraphy and paleogeographic significance of the Pennsylvanian-Permian Bird Spring Formation in the Ship Mountains, southeastern California

    Science.gov (United States)

    Stone, Paul; Stevens, Calvin H.; Howard, Keith A.; Hoisch, Thomas D.

    2013-01-01

    A thick sequence of limestone, dolomite, and minor sandstone assigned to the Pennsylvanian and lower Permian Bird Spring Formation is exposed in the Ship Mountains about 85 kilometers (km) southwest of Needles, California, in the eastern Mojave Desert. These strata provide a valuable reference section of the Bird Spring Formation in a region where rocks of this age are not extensively exposed. This section, which is about 900 meters (m) thick, is divided into five informal members. Strata of the Bird Spring Formation in the Ship Mountains originated as shallow-water marine deposits on the broad, southwest-trending continental shelf of western North America. Perpendicular to the shelf, the paleogeographic position of the Ship Mountains section is intermediate between those of the thicker, less terrigenous, more seaward section of the Bird Spring Formation in the Providence Mountains, 55 km to the northwest, and the thinner, more terrigenous, more landward sections of the Supai Group near Blythe, 100 km to the southeast. Parallel to the shelf, the Ship Mountains section is comparable in lithofacies and inferred paleogeographic position to sections assigned to the Callville Limestone and overlying Pakoon Limestone in northwestern Arizona and southeastern Nevada, 250 km to the northeast. Deposition of the Bird Spring Formation followed a major rise in eustatic sea level at about the Mississippian- Pennsylvanian boundary. The subsequent depositional history was controlled by episodic changes in eustatic sea level, shelf subsidence rates, and sediment supply. Subsidence rates could have been influenced by coeval continental-margin tectonism to the northwest.

  20. New fusulinids from Lower Permian turbidites at Conglomerate Mesa, southeastern inyo Mountains, east-central California

    Science.gov (United States)

    Stevens, C.H.; Stone, P.

    2009-01-01

    Seven previously unrecognized fusulinid species from Lower Permian (Wolfcampian and Leonardian) turbidites near Conglomerate Mesa in east-central California, four of which are named as new species, are here described and figured. The four new species are Schwagerina merriami, S. wildei, Parafusulina mackevetti, and Skinnerella rossi. These fusulinid species have close affinities to similar taxa in Texas and northeastern Nevada, and they are distinct from some other faunas of slightly different age in the Conglomerate Mesa area that are dominated by endemic species and other species with Eastern Klamath Mountains affinities.

  1. Status and understanding of groundwater quality in the Northern Coast Ranges study unit, 2009: California GAMA Priority Basin Project

    Science.gov (United States)

    Mathany, Timothy M.; Belitz, Kenneth

    2015-01-01

    Groundwater quality in the 633-square-mile (1,639-square-kilometer) Northern Coast Ranges (NOCO) study unit was investigated as part of the Priority Basin Project (PBP) of the Groundwater Ambient Monitoring and Assessment (GAMA) Program and the U.S. Geological Survey (USGS) National Water-Quality Assessment Program. The study unit is composed of two study areas (Interior Basins and Coastal Basins) and is located in northern California in Napa, Sonoma, Lake, Colusa, Mendocino, Glenn, Humboldt, and Del Norte Counties. The GAMA-PBP is being conducted by the California State Water Resources Control Board in collaboration with the USGS and the Lawrence Livermore National Laboratory.

  2. Crustal Structure Within the Southeastern Carpathian Arc, Transylvanian Basin, Romania from Teleseismic Receiver Functions

    Science.gov (United States)

    Stanciu, A. C.; Russo, R. M.; Mocanu, V. I.; Munteanu, L.

    2013-05-01

    We present new measurements of receiver functions at 4 broadband stations temporarily deployed in the Transylvanian Basin within the Carpathian Arc, Romania. Receiver functions can reveal depths to sharp crustal seismic velocity boundaries, which in complex tectonic environments such as the study area provide a good diagnostic for the regional tectonics. As a result of Africa (Adria) collision with Europe and subduction of a part of Tethys Ocean, Tisza-Dacia and Alcapa blocks escaped the collision and were emplaced in an embayment of this ocean, and form today the basement of the Transylvanian Basin. The collision of these terranes with the European continent culminated in the formation, in the Romanian part, of the Eastern Carpathians at the contact between the Transylvanian Basin and the East European Platform along the Tornquist-Teisseyre Suture zone, and of Southern Carpathians at the contact with Moesian Platform. In the foreland of the Carpathian Bend Zone, connecting the two mountain chains, in a very constrained area, a high velocity seismic body was contoured by hypocenters between 70 and 200 km depth. We constructed receiver functions using teleseismic P waves generated by events located between 30 and 95 degrees epicentral angle using the method of Ligorria and Ammon (1999) for individual measurements. We used the H-K method of Zhu and Kanamori (2000) to derive boundary interfaces depths and receiver function complexity from binned stacks. Preliminary results show a relatively shallow Moho depth beneath the Transylvanian Basin.

  3. Dissolved Pesticide Concentrations Detected in Storm-Water Runoff at Selected Sites in the San Joaquin River Basin, California, 2000-2001

    National Research Council Canada - National Science Library

    Orlando, James L; Kuivila, Kathryn M; Whitehead, Andrew

    2003-01-01

    ...) and the University of California Davis Bodega Marine Laboratory (BML) water samples were collected at three sites within the San Joaquin River Basin of California and analyzed for dissolved pesticides...

  4. Three-dimensional geologic model of the southeastern Espanola Basin, Santa Fe County, New Mexico

    Science.gov (United States)

    Pantea, Michael P.; Hudson, Mark R.; Grauch, V.J.S.; Minor, Scott A.

    2011-01-01

    This multimedia model and report show and describe digital three-dimensional faulted surfaces and volumes of lithologic units that confine and constrain the basin-fill aquifers within the Espanola Basin of north-central New Mexico. These aquifers are the primary groundwater resource for the cities of Santa Fe and Espanola, six Pueblo nations, and the surrounding areas. The model presented in this report is a synthesis of geologic information that includes (1) aeromagnetic and gravity data and seismic cross sections; (2) lithologic descriptions, interpretations, and geophysical logs from selected drill holes; (3) geologic maps, geologic cross sections, and interpretations; and (4) mapped faults and interpreted faults from geophysical data. Modeled faults individually or collectively affect the continuity of the rocks that contain the basin aquifers; they also help define the form of this rift basin. Structure, trend, and dip data not previously published were added; these structures are derived from interpretations of geophysical information and recent field observations. Where possible, data were compared and validated and reflect the complex relations of structures in this part of the Rio Grande rift. This interactive geologic framework model can be used as a tool to visually explore and study geologic structures within the Espanola Basin, to show the connectivity of geologic units of high and low permeability between and across faults, and to show approximate dips of the lithologic units. The viewing software can be used to display other data and information, such as drill-hole data, within this geologic framework model in three-dimensional space.

  5. Simulations of hydrologic response in the Apalachicola-Chattahoochee-Flint River Basin, Southeastern United States

    Science.gov (United States)

    LaFontaine, Jacob H.; Jones, L. Elliott; Painter, Jaime A.

    2017-12-29

    A suite of hydrologic models has been developed for the Apalachicola-Chattahoochee-Flint River Basin (ACFB) as part of the National Water Census, a U.S. Geological Survey research program that focuses on developing new water accounting tools and assessing water availability and use at the regional and national scales. Seven hydrologic models were developed using the Precipitation-Runoff Modeling System (PRMS), a deterministic, distributed-parameter, process-based system that simulates the effects of precipitation, temperature, land cover, and water use on basin hydrology. A coarse-resolution PRMS model was developed for the entire ACFB, and six fine-resolution PRMS models were developed for six subbasins of the ACFB. The coarse-resolution model was loosely coupled with a groundwater model to better assess the effects of water use on streamflow in the lower ACFB, a complex geologic setting with karst features. The PRMS coarse-resolution model was used to provide inputs of recharge to the groundwater model, which in turn provide simulations of groundwater flow that were aggregated with PRMS-based simulations of surface runoff and shallow-subsurface flow. Simulations without the effects of water use were developed for each model for at least the calendar years 1982–2012 with longer periods for the Potato Creek subbasin (1942–2012) and the Spring Creek subbasin (1952–2012). Water-use-affected flows were simulated for 2008–12. Water budget simulations showed heterogeneous distributions of precipitation, actual evapotranspiration, recharge, runoff, and storage change across the ACFB. Streamflow volume differences between no-water-use and water-use simulations were largest along the main stem of the Apalachicola and Chattahoochee River Basins, with streamflow percentage differences largest in the upper Chattahoochee and Flint River Basins and Spring Creek in the lower Flint River Basin. Water-use information at a shorter time step and a fully coupled simulation in

  6. Groundwater flow and solute transport at the Mourquong saline-water disposal basin, Murray Basin, southeastern Australia

    Science.gov (United States)

    Simmons, Craig; Narayan, Kumar; Woods, Juliette; Herczeg, Andrew

    2002-03-01

    Saline groundwater and drainage effluent from irrigation are commonly stored in some 200 natural and artificial saline-water disposal basins throughout the Murray-Darling Basin of Australia. Their impact on underlying aquifers and the River Murray, one of Australia's major water supplies, is of serious concern. In one such scheme, saline groundwater is pumped into Lake Mourquong, a natural groundwater discharge complex. The disposal basin is hydrodynamically restricted by low-permeability lacustrine clays, but there are vulnerable areas in the southeast where the clay is apparently missing. The extent of vertical and lateral leakage of basin brines and the processes controlling their migration are examined using (1) analyses of chloride and stable isotopes of water (2H/1H and 18O/16O) to infer mixing between regional groundwater and lake water, and (2) the variable-density groundwater flow and solute-transport code SUTRA. Hydrochemical results indicate that evaporated disposal water has moved at least 100 m in an easterly direction and that there is negligible movement of brines in a southerly direction towards the River Murray. The model is used to consider various management scenarios. Salt-load movement to the River Murray was highest in a "worst-case" scenario with irrigation employed between the basin and the River Murray. Present-day operating conditions lead to little, if any, direct movement of brine from the basin into the river. Résumé. Les eaux souterraines salées et les effluents de drainage de l'irrigation sont stockés dans environ 200 bassins naturels ou artificiels destinés à retenir les eaux salines dans tout le bassin de Murray-Darling, en Australie. Leur impact sur les aquifères sous-jacents et sur la rivière Murray, l'une des principales ressources en eau d'Australie, constitue un problème grave. Dans une telle situation, les eaux souterraines salines sont pompées dans le lac Mourquong, complexe dans lequel les nappes se d

  7. Regional skew for California, and flood frequency for selected sites in the Sacramento-San Joaquin River Basin, based on data through water year 2006

    Science.gov (United States)

    Parrett, Charles; Veilleux, Andrea; Stedinger, J.R.; Barth, N.A.; Knifong, Donna L.; Ferris, J.C.

    2011-01-01

    Improved flood-frequency information is important throughout California in general and in the Sacramento-San Joaquin River Basin in particular, because of an extensive network of flood-control levees and the risk of catastrophic flooding. A key first step in updating flood-frequency information is determining regional skew. A Bayesian generalized least squares (GLS) regression method was used to derive a regional-skew model based on annual peak-discharge data for 158 long-term (30 or more years of record) stations throughout most of California. The desert areas in southeastern California had too few long-term stations to reliably determine regional skew for that hydrologically distinct region; therefore, the desert areas were excluded from the regional skew analysis for California. Of the 158 long-term stations used to determine regional skew, 145 have minimally regulated annual-peak discharges, and 13 stations are dam sites for which unregulated peak discharges were estimated from unregulated daily maximum discharge data furnished by the U.S. Army Corp of Engineers. Station skew was determined by using an expected moments algorithm (EMA) program for fitting the Pearson Type 3 flood-frequency distribution to the logarithms of annual peak-discharge data. The Bayesian GLS regression method previously developed was modified because of the large cross correlations among concurrent recorded peak discharges in California and the use of censored data and historical flood information with the new expected moments algorithm. In particular, to properly account for these cross-correlation problems and develop a suitable regression model and regression diagnostics, a combination of Bayesian weighted least squares and generalized least squares regression was adopted. This new methodology identified a nonlinear function relating regional skew to mean basin elevation. The regional skew values ranged from -0.62 for a mean basin elevation of zero to 0.61 for a mean basin elevation

  8. Evaluation of Petroleum Source Rock Potentials of Imo Shale Southern Anambra Basin, Southeastern Nigeria

    International Nuclear Information System (INIS)

    Ushie, F. A.; Uzoho, N. C.

    2002-01-01

    In order to search economically for oil and gas resources a detailed assessment of the petroleum potential of sedimentary basins is necessary. To achieve this, most explorationists aim to obtain information about the abundance and type of organic matter in the source rock, and to ascertain its maturity. This is usually done using cores and cuttings from wells but sometimes the work must be with samples form a single wall,Initially, this assessment in Nigeria had been restricted mainly to the Niger delta with the resultant discovery of large petroleum deposits both onshore and offshore of the delta. Recently, some oil companies like Agip, Elf and even individuals became interested in the Anambra basin and have studied the source rock potential of some of its formation. An analysis applying geochemical techniques was used to determine the origin of the absorbed bitumen as well as distribution of he organic facies in the Palcocene Imo shale in the Anambra basin, Nigeria. The soluble organic matter (SOM) was examined for the quantity, type, distribution and thermal evolution of the organic matter. AS a basic preliminary screening method all sample were subjected to total organic carbon (TOC) measurement. Sample had TOC values between 0.5-0.6% which proved them to be fair sources. Maturation test using SOM/TOC (transformation ratio) gave a mean value of 0.01 pointing to immaturity of samples. The dominate of aromatics over saturates indicate a gas source for the shales encountered in the locations

  9. Seismic Structural Setting of Western Farallon Basin, Southern Gulf of California, Mexico.

    Science.gov (United States)

    Pinero-Lajas, D.; Gonzalez-Fernandez, A.; Lopez-Martinez, M.; Lonsdale, P.

    2007-05-01

    Data from a number of high resolution 2D multichannel seismic (MCS) lines were used to investigate the structure and stratigraphy of the western Farallon basin in the southern Gulf of California. A Generator-Injector air gun provided a clean seismic source shooting each 12 s at a velocity of 6 kts. Each signal was recorded during 6- 8 s, at a sampling interval of 1 ms, by a 600 m long digital streamer with 48 channels and a spacing of 12.5 m. The MCS system was installed aboard CICESE's (Centro de Investigacion Cientifica y de Educacion Superior de Ensenada) 28 m research vessel Francisco de Ulloa. MCS data were conventionally processed, to obtain post- stack time-migrated seismic sections. The MCS seismic sections show a very detailed image of the sub-bottom structure up to 2-3 s two-way travel time (aprox. 2 km). We present detailed images of faulting based on the high resolution and quality of these data. Our results show distributed faulting with many active and inactive faults. Our study also constrains the depth to basement near the southern Baja California eastern coast. The acoustic basement appears as a continuous feature in the western part of the study area and can be correlated with some granite outcrops located in the southern Gulf of California islands. To the East, near the center of the Farallon basin, the acoustic basement changes, it is more discontinuous, and the seismic sections show a number of diffracted waves.

  10. Waterbird habitat in California's Central Valley basins under climate, urbanization, and water management scenarios

    Science.gov (United States)

    Matchett, Elliott L.; Fleskes, Joseph

    2018-01-01

    California's Central Valley provides critical, but threatened habitat and food resources for migrating and wintering waterfowl, shorebirds, and other waterbirds. The Central Valley is comprised of nine basins that were defined by the Central Valley Joint Venture (CVJV) to assist in conservation planning. Basins vary in composition and extent of habitats, which primarily include croplands and wetlands that rely on water supplies shared with other competing human and environmental uses. Changes in climate, urban development, and water supply management are uncertain and could reduce future availability of water supplies supporting waterbird habitats and limit effectiveness of wetland restoration planned by the CVJV to support wintering waterbirds. We modeled 17 plausible scenarios including combinations of three climate projections, three urbanization rates, and five water supply management options to promote agricultural and urban water uses, with and without wetland restoration. Our research examines the reduction in quantity and quality of habitats during the fall migration-wintering period by basin under each scenario, and the efficacy of planned wetland restoration to compensate reductions in flooded areas of wetland habitats. Scenario combinations of projected climate, urbanization, and water supply management options reduced availability of flooded cropland and wetland habitats during fall-winter and degraded the quality of seasonal wetlands (i.e., summer-irrigation for improved forage production), though the extent and frequency of impacts varied by basin. Planned wetland restoration may substantially compensate for scenario-related effects on wetland habitats in each basin. However, results indicate that Colusa, Butte, Sutter, San Joaquin, and Tulare Basins may require additional conservation to support summer-irrigation of seasonal wetlands and winter-flooding of cropland habitats. Still further conservation may be required to provide sufficient areas of

  11. Shear-Wave Splitting Within the Southeastern Carpathian Arc, Transylvanian Basin, Romania

    Science.gov (United States)

    Stanciu, A. C.; Russo, R. M.; Mocanu, V. I.; Munteanu, L.

    2012-12-01

    We present 75 new measurements of shear wave splitting at 4 temporary broadband seismic stations that we deployed in the Transylvanian Basin within the Carpathian Arc, Romania. The Tisza-Dacia terranes, which form the basement of this basin, were accommodated in the space between the thick, old, rigid and cold East European Platform and the Moesian Platform during the Miocene. This movement was driven by the subduction of a part of the Tethys Ocean, which led to the formation of Carpathian orogen system. In Romania, the mountains are divided into the Eastern Carpathians, at the limit of Transylvanian Basin and the East European Platform along the Tornquist-Teisseyre Suture Zone, and the Southern Carpathians, at the limit with Moesian Platform. They connect to the West of the Carpathian Bend Zone where a very active high velocity seismic body generates intermediate depth earthquakes between 70 and 200 km beneath the Vrancea seismogenic zone. We analyzed splitting of SKS and SKKS phases recorded at epicentral distances between 87 and 150 degrees using the method of Silver and Chan (1991). We estimated splitting parameters, fast shear polarization azimuth and delay time, using both weighted averages of individual splitting measurements (Helffrich et al., 1994) and simultaneous linearization of all clearly recorded SK(K)S waves (Wolfe and Silver, 1998). For COMD, located at the contact of the Carpathian Bend Zone and Transylvanian Basin, we obtained a fast shear polarization azimuth trending NE-SW, parallel to the contact and to the strike of the Vrancea seismic body. For 10 suitable events recorded at IACB, at the contact of the Neogene Volcanic zone with the Eastern Carpathians, we did not observe any splitting; we consider the station splitting to be null. The fast shear polarization azimuth for PMAR, at the limit between Tisza-Dacia block and Southern Carpathians thrust belt, and at CHDM, within the Transylvanian Basin, is NW-SE similar to a regional splitting

  12. Flux and distribution of methane (CH4) in the Gunsan Basin of the southeastern Yellow Sea, off the Western Korea.

    Science.gov (United States)

    Lee, Jun-Ho; Woo, Han Jun; Son, Seung-Kyu; Kim, Moonkoo; Lee, Dong-Hun; Tsunogai, Urumu; Jeong, Kap-Sik

    2018-04-16

    The flux and distribution of methane (CH 4 ) was investigated in the seawater column at 14 stations in the Gunsan Basin, the southeastern part of Yellow Sea from 2013 to 2015. Here CH 4 is concentrated 2.4-4.7 (3.4 ± 0.7) nM in the surface and 2.5-7.4 (5.2 ± 1.7) nM in the bottom layer. The CH 4 saturation ratios ranged from 65.5% to 295.5% (162.6 ± 68.7), comprising the mean sea-to-air CH 4 flux of 3.8 to 25.3 (15.6 ± 5.5) µM m -2 d -1 . Methane concentration was largely different in the upper and the lower seawater layers that is separated by the thermocline of which depth is variable (20-60 m) depending on the time of sampling. The concentration of seawater dissolved CH 4 is high between the bottom surface of the thermocline layer and the sea floor. Generally it tends to decrease from the south-westernmost part of the basin toward the west coast of Korea. This distribution pattern of CH 4 seems to result from the CH 4 supply by decomposition of organic matters produced in the upper seawater layer that is superimposed by the larger supply from the underlying sediment layer especially beneath the thermocline. The latter is manifested by ubiquitous CH 4 seeps from the seafloor sediments.

  13. Reservoir storage and hydrologic responses to droughts in the Paraná River basin, south-eastern Brazil

    Directory of Open Access Journals (Sweden)

    D. D. C. D. Melo

    2016-11-01

    Full Text Available Droughts are particularly critical for Brazil because of impacts on water supply and because most (70 % of its electricity is derived from hydroelectric generation. The Paraná basin (PB, a major hydroelectric producing region with 32 % (60 million people of Brazil's population, recently experienced the most severe drought since the 1960s, compromising the water supply for 11 million people in São Paulo. The objective of this study is to quantify linkages between meteorological and hydrological droughts based on remote sensing, modelling, and monitoring data using the Paraná River basin in south-eastern Brazil as a case study. Two major meteorological droughts were identified in the early 2000s and 2014, with precipitation 20–50 % below the long-term mean. Total water storage change estimated from the Gravity Recovery and Climate Experiment (GRACE satellites declined by 150 km3 between April 2011 and April 2015. Simulated soil moisture storage declined during the droughts, resulting in decreased runoff into reservoirs. As a result, reservoir storage decreased by 30 % relative to the system's maximum capacity, with negative trends ranging from 17 (May 1997–April 2001 to 25 km3 yr−1 (May 2011–April 2015. Storage in upstream reservoirs is mostly controlled by natural climate forcing, whereas storage in downstream reservoirs also reflects dam operations. This study emphasizes the importance of integrating remote sensing, modelling, and monitoring data to evaluate droughts and to establish a preliminary understanding of the linkages between a meteorological and hydrological drought for future management.

  14. Dryness of ephemeral lakes and consequences for dust activity: the case of the Hamoun drainage basin, southeastern Iran.

    Science.gov (United States)

    Rashki, A; Kaskaoutis, D G; Goudie, A S; Kahn, R A

    2013-10-01

    This study examines the influence of changes in the water coverage in the Hamoun dry-bed lakes on visibility, dust outbreaks, aerosol loading and land-atmospheric fluxes over the region covering the period 1985-2005. The Hamoun basin, located on the southeastern Iran and western Afghanistan borders, has been recognized as one of the major dust source regions in south Asia and is covered by shallow, marshy lakes that are fed by the Helmand and Farahrood rivers. When the water in watersheds that support the lakes is drawn down for natural or human-induced reasons, the end result is a decrease in the water coverage in the basin, or even complete dryness as occurred in 2001. Then, strong seasonal winds, mainly in summer, blow fine sand and silt off the exposed lakebed, enhancing dust activity and aerosol loading over the region. Satellite (Landsat) and meteorological observations reveal that the water levels in the Hamoun lakes exhibit considerable inter-annual variability during the period 1985-2005 strongly related to anomalies in precipitation. This is the trigger for concurrent changes in the frequency of the dusty days, aerosol loading and deterioration of visibility over the region, as satellite (TOMS, MODIS, MISR) observations reveal. On the other hand, soil moisture and latent heat, obtained via model (GLDAS_noah-10) simulations are directly linked with water levels and precipitation over the region. The desiccation of the Hamoun lakes in certain years and the consequent increase in frequency and intensity of dust storms are serious concerns for the regional climate, ecosystems and human health. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Rapid subsidence and stacked Gilbert-type fan deltas, Pliocene Loreto basin, Baja California Sur, Mexico

    Science.gov (United States)

    Dorsey, Rebecca J.; Umhoefer, Paul J.; Renne, Paul R.

    1995-08-01

    Pliocene nonmarine to marine sedimentary rocks exposed in the Loreto basin, Baja California Sur, provide a record of syntectonic subsidence and sedimentation in a transform-rift basin that developed along the western margin of the Gulf of California. A thick sequence of twelve Gilbert-type fan deltas, having a total measured thickness of about 615 m, accumulated near the fault-bounded southwestern margin of this basin. Based on stratal geometries and lithofacies associations, sedimentary rocks are divided into Gilbert-delta topset, foreset and bottomset strata, shell beds and background shallow-marine shelf deposits. Topset strata of each Gilbert-type delta cycle are capped by laterally persistent molluscan shell beds containing diverse assemblages of bivalves, pectens, oysters, gastropods and echinoids. These shell beds are interpreted to be condensed intervals that record sediment starvation during abandonment of the fan-delta plain. Delta abandonment may have been caused by large episodic faulting events, which submerged each pre-existing fan-delta plain, substantially slowed detrital input by drowning of alluvial feeder channels, and created new accommodation space for each new Gilbert-type fan delta. Alternatively, it is possible that delta-plain abandonment was caused by upstream avulsions and autocyclic lateral switching of fan-delta lobes during relatively uniform rates of slip along the basin-bounding fault. Two contrasting, plausible basin models are proposed for the Loreto basin: (1) asymmetric subsidence along a high-angle oblique-slip normal fault, producing a classic half-graben basin geometry with vertically stacked Gilbert-type fan deltas; or (2) lateral stacking and horizontal displacement of strata away from a relatively fixed depocenter due to fault movement in the releasing bend of a listric strike-slip fault. We favor the first model because field relations and simple geometric constraints suggest that most of the total measured section

  16. The geological setting of Santa Monica and San Pedro Basins, California Continental Borderland

    Science.gov (United States)

    Gorsline, D. S.

    The California Continental Borderland's present configuration dates from about 4 to 5 × 10 6 years before present (BP) and is the most recent of several configuration of the southern California margin that have evolved after the North America plate over-rode the East Pacific Rise about 30 × 10 6 years ago. The present morphology is a series of two to three northwest-southeast trending rows of depressions separated by banks and insular ridges. Two inner basins, Santa Monica and San Pedro, have been the site for the California Basin Study (CaBs), funded by the US Department of Energy. The Santa Monica and San Pedro Basins contain post-Miocene sediment thicknesses of about 2.5 and 1.5 km respectively. During the Holocene (past 10,000 years) about 10-12m have accumulated. The sediment entered the basin by one or a combination of processes including particle infall (mainly as bioaggregates) from surface waters, from nepheloid plumes (surface, mid-depth and near-bottom), from turbidity currents, mass movements, and to a very minor degree direct precipitation. In Santa Monica Basin, during the last century, particle infall nepheloid plume transport have been the most common processes. The former process has been dominant in thecentral basin at water depths from 900-945m, where characteristic silt-clay is found with a typical mean particle diameter of about 0.0006mm ( φ standard deviation = 2; φ skewness near zero). Kurtosis is typically 2 (platykurtic); these values indicate broad, near-log normal particle size distributions. The calcium carbonate content averages about 10% and organic carbon about 4%. Surficial sediment bulk densities are 1.1-1.2 and accumulation rates range from 16-30mg cm -2Yr 1 in this central fine deposit. Bottom water oxygen contents are at or below 0.1 ml 1 -1 so that bioturbation is inhibited, thus preserving the primary sedimentary stratification. There appear to be annual varves, but the laminae couplets are not simple wet-dry season pairs

  17. Quaternary tectonics and basin history of Pahrump and Stewart Valleys, Nevada and California

    International Nuclear Information System (INIS)

    Hoffard, J.L.

    1991-05-01

    The Pahrump fault system is an active fault system located in Pahrump and Stewart Valleys, Nevada and California, in the southern part of the Basin and Range Province. This system is 50 km long by 30 km wide and is comprised of three fault zones: the right-lateral East Nopah fault zone, the right-oblique Pahrump Valley fault zone, and the normal West Spring Mountains fault zone. All three zones have geomorphic evidence for late Quaternary activity. Analysis of active fault patterns and seismic reflection lines suggests that the Pahrump basin has had a two-stage genesis, an early history associated with a period of low angle detachment faulting probably active 10-15 Ma, and a more recent history related to the present dextral shear system, probably active post-4 Ma

  18. Systematic heat flow measurements across the Wagner Basin, northern Gulf of California

    Science.gov (United States)

    Neumann, Florian; Negrete-Aranda, Raquel; Harris, Robert N.; Contreras, Juan; Sclater, John G.; González-Fernández, Antonio

    2017-12-01

    A primary control on the geodynamics of rifting is the thermal regime. To better understand the geodynamics of rifting in the northern Gulf of California we systematically measured heat-flow across the Wagner Basin, a tectonically active basin that lies near the southern terminus of the Cerro Prieto fault. The heat flow profile is 40 km long, has a nominal measurement spacing of ∼1 km, and is collocated with a seismic reflection profile. Heat flow measurements were made with a 6.5-m violin-bow probe. Although heat flow data were collected in shallow water, where there are significant temporal variations in bottom water temperature, we use CTD data collected over many years to correct our measurements to yield accurate values of heat flow. After correction for bottom water temperature, the mean and standard deviation of heat flow across the western, central, and eastern parts of the basin are 220 ± 60, 99 ± 14, 889 ± 419 mW m-2, respectively. Corrections for sedimentation would increase measured heat flow across the central part of basin by 40 to 60%. We interpret the relatively high heat flow and large variability on the western and eastern flanks in terms of upward fluid flow at depth below the seafloor, whereas the lower and more consistent values across the central part of the basin are suggestive of conductive heat transfer. Moreover, heat flow across the central basin is consistent with gabbroic underplating at a depth of 15 km and suggests that continental rupture here has not gone to completion.

  19. Monitoring Aquifer-Storage Change and Land Subsidence Related to Groundwater Withdrawal in the Willcox and Douglas Groundwater Basins in Southeastern Arizona

    Science.gov (United States)

    Carruth, R. L.; Conway, B. D.

    2015-12-01

    Groundwater is the primary source of water in the Willcox and Douglas Basins in southeastern Arizona and about 90 percent of the groundwater withdrawal is for agriculture. It is estimated that current groundwater production exceeds recharge by at least a factor of two in the Douglas Basin and by a factor of three to eight in the Willcox Basin. The groundwater mining has resulted in groundwater declines of as much as 105 feet in the Willcox Basin between 2006 and the present and 52 feet in the Douglas Basin between 2005 and the present. The U.S. Geological Survey collected repeat absolute gravity measurements at 8 sites in the Willcox Basin and at 4 sites in the Douglas Basin for the purpose of measuring the change in aquifer storage between 2008 and 2014. All sites in the Willcox Basin showed aquifer-storage loss between 2008 and 2014, with values ranging from 0.5 to 8.5 feet of water. In the Douglas Basin, two sites showed aquifer-storage loss of 0.8 feet and 3.0 feet, respectively. Additionally, two sites in the Douglas Basin showed storage increases of 2.0 feet and 2.9 feet of water in storage. The storage increases are attributed to the sites being close to ephemeral streams where two large precipitation and associated runoff events (remnant East Pacific hurricanes) occurred shortly before the gravity measurements in 2014. The Arizona Department of Water Resources has identified three major areas of land subsidence using Interferometric Synthetic Aperture Radar (InSAR) data - two in the Willcox Basin and one in the Douglas Basin. Land subsidence of as much as 29 inches in the Willcox Basin and 18 inches in the Douglas Basin has occurred between 2006 and the present—the magnitude and rates of human-induced subsidence have caused earth fissures and impacted roads, a power generation facility, and a railway. The declining groundwater levels, decrease in aquifer storage, and land subsidence are a challenge for future groundwater availability in the Willcox and

  20. Conceptual Model for the Geothermal System of the Wagner Basin, Gulf of California

    Science.gov (United States)

    Gonzalez-Fernandez, A.; Neumann, F.; Negrete-Aranda, R.; Contreras, J.; Batista-Cruz, R. Y.; Kretzschmar, T.; Avilés-Esquivel, T. A.; Reyes Ortega, V.; Flores-Luna, C. F.; Gomez-Trevino, E.; Martin, A.; Constable, S.

    2017-12-01

    Cerro Prieto in northwestern Mexico is one of the biggest geothermal plants in the world. Cerro Prieto sits in the Gulf of California rift system, which consists of a series of spreading centers and transform faults. The aim of this study is to evaluate the geothermal potential of the nearby offshore Wagner basin. To this end, we acquired and analyzed a set of different methods, such as reflection seismics, heat flow, magnetotelluric and controlled source electromagnetics, hydrogeochemistry and echosounder. Seismic reflection data show that the Wagner basin is a semi-graben, A profile crossing it shows numerous closely spaced faults, particularly in its eastern part. We found very high heat flow values, in excess of 1000 mW/m2, and large variability on the eastern flank of the Wagner basin, whereas there are more consistent and much lower values across the central and western parts. The high and variable heat flow values are suggestive of advective heat transfer We collected cores and interstitial water samples. The hydrogeochemistry analyses show that in the cores recovered from high heat flow areas, the relations bromide/choride and bromide/sulfide are clearly different from sea water. In contrast, those relations were close to sea water in areas with low heat flow. Similarly, the isotope relations such as 2H/18O show a similar pattern, further indicating the groundwater origin of the interstitial water found in high heat flow zones. In the magnetoteluric measurements we found the presence of a deep conductor that is located approximately under the basin center, extends from the base of the crust to depths of about 40 km, and dips toward the NE. This conductor is probably related to the heat source of the geothermal system. Active source electromagnetics show the presence of shallow conductors that correlate with the faults visible in the seismic sections. There are two distinct conductors, one in the eastern flank and another in the western flank of the basin

  1. Microlepidogaster discus, a new species of Hypoptopomatinae (Siluriformes: Loricariidae) from the rio Jequitinhonha basin, southeastern Brazil.

    Science.gov (United States)

    Martins, Fernanda O; Rosa, Alaina C; Langeani, Francisco

    2014-10-20

    A new Hypoptopomatinae is described from the upper rio Jequitinhonha basin. The new species is distinguished from all congeners by having the ventral laminar expansions of cleithrum and coracoid bearing only 1-30 odontodes, restricted to the area near the pectoral-fin insertion; the anterior plates of mid-ventral lateral series reduced, not ventrally elongated, the first or the second markedly round; pectoral-fin unbranched ray distinctly divided distally, with 7-15 ossified segments, reaching almost half of its length; and accessory process on first epibranchial present. Microlepidogaster discus is further distinguished from its congeners by several other osteological features. The problems concerning the taxonomy of Microlepidogaster, as well as the pattern of distribution of the genus, are discussed.

  2. Iron sulfide precipitation sequence in Albian coals from the Maestrazgo Basin, southeastern Iberian Range, Northeastern Spain

    Energy Technology Data Exchange (ETDEWEB)

    Querol, X.; Chinchon, S.; Lopez-Soler, A.

    1989-03-01

    Deposition of important coal accumulations in the proximal areas of a delta-estuary, occurred in the Maestrazgo Basin during the middle Albian (late Lower Cretaceous). These coals are characterized by high sulfur contents: 4.18% in coal from the Castellote subbasin, and 7.16% in coal from the Calanda subbasin (dry basis). A petrographic study of iron sulfide was carried out on the subject coals, to deduce an iron sulfide precipitation sequence for five principal stages: (a) early syngenetic stage; (b) late syngenetic stage; (c) syngenetic-diagenetic stage; (d) early epigenetic stage; and (e) late epigenetic stage. A sulfide precipitation control during the syngenetic stage, carried out by different compounds liberated from organic matter during its coalification stages, is deduced from the confrontation with other studies on coal differing in rank, depositional environment and geographical location. 16 refs., 19 figs.

  3. Subsidence and Extension Rates of Laguna Salada Basin, Northeastern Baja California, Mexico

    Science.gov (United States)

    Contreras, J.; Martin-Barajas, A.; Herguera, J. C.

    2002-12-01

    Laguna Salada basin in northeastern Baja California, Mexico, is an active half-graben product of the trans-tensional tectonics of the Gulf of California. It lies at the boundary between the North America and Pacific plates, 15 km west of the Cerro Prieto-Imperial fault system. We present the results of a time series analysis of the uppermost 980 m of a gamma ray log from the geothermal exploratory well ELS1 drilled in the proximity of the Laguna Salada fault, which bounds the basin on its eastern margin. Our analysis indicates its stratigraphy is cyclical and that the spectrum of the gamma ray log is similar to the spectrum of δ18O Pleistocene variations, which strongly suggest an orbital origin. Based on this, we establish a correlation between the gamma ray log and δ18O stages to constrain ages of sediments with an estimated uncertainty of ~10 kyr. We found that sedimentation rates at ELS1 site have remained constant during the last 780 kyr. The sedimentation rate at the ELS1 site is 1.6 mm/yr. This value is extrapolated to obtain the vertical and perpendicular to strike slip rates of Laguna Salada fault. It was found that the vertical slip component is 4.22 mm/yr and the perpendicular to strike slip component (E-W direction) is 1.55 mm/yr.

  4. Evolution and diagenesis of Pennsylvanian phylloid algal bioherms in the Paradox basin of southeastern Utah

    Energy Technology Data Exchange (ETDEWEB)

    Gournay, J.P. (Univ. of Texas, Austin, TX (United States))

    1996-01-01

    Three lower Ismay (Paradox Formation) bioherms, were examined at Honaker Trail, Soda Basin, and Eight Foot Rapids along the San Juan River. Approximately 150 samples were collected at approximately 0.5 m vertically spaced intervals. Samples of unique lithologies were also collected. The lower Ismay bioherms studied lie along an east-west traverse with respect to each other and display slight differences in internal facies composition. Phylloid algae generally dominate the bioherms, but associated biota include: fusulinids, crinoids, bryozoans, ostracods, minor trilobites, and rugose corals. Facies changes and the presence of numerous stylolitized layers within the bioherms suggest distinct growth phases. Additionally, the phylloid-rich layers appear to exhibit vertical variations in total micrite. Variations in facies and micrite composition may be controlled by sea level fluctuation or may reflect microbial activity. Consistent variation in porosity and permeability within bioherms may reflect high order cyclical events, possibly sixth order. Throughout the bioherms studied, variations in porosity and permeability correspond to variations in lithology. The bioherms are homogenous laterally, but heterogeneous vertically and the porosity zones reflect this. The zones are characterized by moldic porosity, increased abundances of phylloid algae, and each is capped by a mud-rich unit. Many of the porous zones are about 2 m thick with two or three associated smaller bands. The smaller bands are completely compartmentalized from the major bands. This information is of significant importance to production from phylloid algal reservoir systems.

  5. Evolution and diagenesis of Pennsylvanian phylloid algal bioherms in the Paradox basin of southeastern Utah

    Energy Technology Data Exchange (ETDEWEB)

    Gournay, J.P. [Univ. of Texas, Austin, TX (United States)

    1996-12-31

    Three lower Ismay (Paradox Formation) bioherms, were examined at Honaker Trail, Soda Basin, and Eight Foot Rapids along the San Juan River. Approximately 150 samples were collected at approximately 0.5 m vertically spaced intervals. Samples of unique lithologies were also collected. The lower Ismay bioherms studied lie along an east-west traverse with respect to each other and display slight differences in internal facies composition. Phylloid algae generally dominate the bioherms, but associated biota include: fusulinids, crinoids, bryozoans, ostracods, minor trilobites, and rugose corals. Facies changes and the presence of numerous stylolitized layers within the bioherms suggest distinct growth phases. Additionally, the phylloid-rich layers appear to exhibit vertical variations in total micrite. Variations in facies and micrite composition may be controlled by sea level fluctuation or may reflect microbial activity. Consistent variation in porosity and permeability within bioherms may reflect high order cyclical events, possibly sixth order. Throughout the bioherms studied, variations in porosity and permeability correspond to variations in lithology. The bioherms are homogenous laterally, but heterogeneous vertically and the porosity zones reflect this. The zones are characterized by moldic porosity, increased abundances of phylloid algae, and each is capped by a mud-rich unit. Many of the porous zones are about 2 m thick with two or three associated smaller bands. The smaller bands are completely compartmentalized from the major bands. This information is of significant importance to production from phylloid algal reservoir systems.

  6. Status of aeromagnetic survey coverage of Yucca Mountain and vicinity to a radius of about 140 kilometers, southwestern Nevada and southeastern California, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Sikora, R.F.; Ponce, D.A.; Oliver, H.W.

    1993-12-31

    Fifty aeromagnetic surveys in the southwestern part of Nevada and the southeastern part of California have been evaluated to assess the quality and coverage of aeromagnetic data within 140 kilometers (km) of a potential nuclear waste repository at Yucca Mountain, Nevada. The compilation shows that all the study area is covered by aeromagnetic surveys, but in some areas, particularly in the Death Valley region, new surveys flown with closer flight line spacing and lower elevations than the existing coverage are needed. In addition, the California part of the study area needs to be analytically continued downward to 305 meters (m) above ground level to provide a consistent data set for interpretation of subsurface geologic structures.

  7. Status of aeromagnetic survey coverage of Yucca Mountain and vicinity to a radius of about 140 kilometers, southwestern Nevada and southeastern California, 1992

    International Nuclear Information System (INIS)

    Sikora, R.F.; Ponce, D.A.; Oliver, H.W.

    1993-01-01

    Fifty aeromagnetic surveys in the southwestern part of Nevada and the southeastern part of California have been evaluated to assess the quality and coverage of aeromagnetic data within 140 kilometers (km) of a potential nuclear waste repository at Yucca Mountain, Nevada. The compilation shows that all the study area is covered by aeromagnetic surveys, but in some areas, particularly in the Death Valley region, new surveys flown with closer flight line spacing and lower elevations than the existing coverage are needed. In addition, the California part of the study area needs to be analytically continued downward to 305 meters (m) above ground level to provide a consistent data set for interpretation of subsurface geologic structures

  8. Basin-wide erosion rates of a relict surface in the southeastern Tibetan Plateau from in-situ produced 10Be in fluvial sediments

    Science.gov (United States)

    Fu, Ping; Stroeven, Arjen; Harbor, Jonathan; Heyman, Jakob; Caffee, Marc

    2017-04-01

    Over geological time Earth's surface undergoes radical changes. Few regions display these changes more than the Tibetan Plateau, a dynamic region undergoing changes brought about by tectonic and climatic forcing. Our goal is to quantify surface erosion rates on the Tibetan Plateau. Characterizing the surficial changes and the underlying causes are significant goals that require quantitative tools. With the development of AMS and improved understanding of nuclide production rates, in-situ produced cosmogenic nuclide dating has become increasingly effective for quantifying surface exposure age and erosion rates. Likewise, in-situ cosmogenic 10Be has been successfully to determine basin-wide erosion rates in many geological setting. However, quantifying fluvial erosion rates from glaciated basins using cosmogenic nuclide concentrations in fluvial sediments has limitations because burial by ice and glacial erosion can strongly reduce concentrations or entirely reset the cosmogenic nuclide clock in a landscape, which in turn leads to overestimation of fluvial erosion rates. In this study, we measured 10Be concentrations in river sand samples from both previously glaciated basins and non-glaciated basins, on a low-relief relict surface and the surrounding mountain area, respectively, in the southeastern Tibetan Plateau. The results show that fluvial sediments from glaciated basins have higher cosmogenic nuclide concentrations than expected given the deglaciation ages for these basins. Derived basin wide erosion rates are therefore significantly lower for glaciated basins than for non-glaciated basins. We interpret the high cosmogenic nuclide concentrations as a result of nuclide inheritance from before the last glaciation. In contrast to others studies indicating that overestimation of fluvial erosion rates can occur due to glacial erosion, our results suggest that in the case of a formerly glaciated relict surface in southeastern Tibet (largely preserved under non

  9. Subsidence History of the Laguna Salada Basin in Northeastern Baja California, Mexico

    Science.gov (United States)

    Contreras, J.; Martin-Barajas, A.; Herguera, J.

    2008-12-01

    The Salton Trough region in southern California and the Mexicali valley in northwestern Mexico are areas of (i) rapid subsidence due to trans-tension along the San Andreas-Imperial fault system, and (ii) high flux of sediments transported by the Colorado River, all of which confer this region with a high potential to preserve a complete record of climatic and tectonic activity information. Here we present the subsidence history of the Laguna Salada basin, and the history of activity of the master bounding faults on its eastern side. The Laguna Salada is a lacustrine basin located west of the Mexicali valley and to the south of the Salton Trough. Sedimentological as well as time series analyses performed on two 42 m-long cores drilled in the center of the basin, estimated to span the past 50 and 70KaBP, indicate a modulation of the late Quaternary stratigraphy by cyclic variations in lake level driven by Milankovitch forcing. Based on these results we derive the long-term history of the basin from a gamma-ray log recovered from a 2.8 km-deep geothermal borehole drilled by the Mexican Power Company adjacent to the Laguna Salada fault. The stratigraphy of the deep borehole reveals a history of activity pulses related to the initial breakage of the Laguna Salada fault and its interaction with neighboring faults. A first pulse started at 1.5 Ma and records the initiation of the Laguna Salada fault and rapid uplift of the crystalline block of the Sierra Cucapa. A second pulse started around 1 Ma, and is very likely related to the hard linking of the Laguna Salada fault with the Cañada David detachment by the Cañon Rojo fault. The onset of the Laguna Salada fault at 1.5 Ma appears to be synchronous with an early Pleistocene regional fault reorganization among the San Jacinto, San Andreas and Elsinore fault systems in southern California, suggesting that this reorganization may have affected a large area from San Gorgonio pass to the northern Gulf of California.

  10. Estimating Historical Land Subsidence and Monitoring Aquifer-Storage Change Related to Groundwater Withdrawal in the Willcox Groundwater Basin in Southeastern Arizona

    Science.gov (United States)

    Conway, B. D.; Carruth, R. L.

    2016-12-01

    Groundwater is the primary source of water in the Willcox Basin in southeastern Arizona and about 90 percent of the groundwater withdrawal is for agriculture. It is estimated that current groundwater production exceeds recharge by a factor of three to eight in the Willcox Basin. The groundwater mining has resulting in historical groundwater declines of more than 100 meters. The U.S. Geological Survey (USGS) collected repeat absolute gravity measurements at 8 sites for the purpose of measuring the change in aquifer storage between 2008 and 2014. All sites showed aquifer-storage loss between 2008 and 2014, with values ranging from 0.2 to 2.6 meters of water. The Arizona Department of Water Resources (ADWR) has identified two major areas of land subsidence using Interferometric Synthetic Aperture Radar (InSAR) data in the Willcox Basin. Land subsidence of as much as 89 centimeters in the Willcox Basin has occurred between 2006 and the present—the magnitude and rates of human-induced subsidence have caused earth fissures and impacted roads, a power generation facility, a railway, and a gas line. ADWR conducted a GNSS survey in the summer of 2016 to determine historical land subsidence throughout the Willcox Basin. The GNSS data, InSAR data, and historical leveling data were then compiled to extrapolate historical land subsidence in the Willcox basin between 1937 and 2016. Land subsidence as much as 1.8 meters was estimated in several areas of the groundwater basin. The declining groundwater levels, decrease in aquifer storage, and land subsidence are a challenge for future groundwater availability in the Willcox Basin. Continued monitoring by the USGS and the ADWR will provide 1) the temporal data needed to understand and evaluate how the hydrogeologic system in the basin is responding through time to groundwater overdraft and 2) provide a scientific basis for future mitigation efforts such as redistribution of pumping and/or a reduction of groundwater withdrawal.

  11. Analysis of hydrogeochemical facies in groundwater of upper part of Cross River Basin, southeastern Nigeria

    Science.gov (United States)

    Stephen, Ukpai N.; Celestine, Okogbue O.; Solomon, Onwuka O.

    2017-07-01

    Upper Cross River Hydrogeological Basin lies within latitudes 60 021N to 60 241N and longitudes 80 001E to 80 161E, and is generally underlain by shales of Asu River group of Albian age. The area has Histories of intensive mineralization which influenced groundwater system, resulting to occurrence of different water types. This study determines the various water types via evaluation of major ion concentration from representative water samples collected across the area. Twenty (20) water samples were analyzed using Spectrophotometer of HACH DR/2010 series, and results showed that groundwater in the area is generally hard and polluted with TDS in some places. Statistical inspection was performed on the results using aqua-chem, and it delineated five hydro-chemical facies, namely: Ca-Mg-Cl-S04, Ca-Mg-HCO3-Cl-SO4, Ca-Mg-HCO3, Na-K-HCO3 and Na-K-Cl-SO4; all lie between slight acidic and weak alkaline water. These chemical facies (water types) diffused from non-point sources in urban area and point source from south of Abakaliki town. The dispersion of the facies plumes is possibly controlled by advection process through structural weak zones such as fractures. Hydraulic heads determined from hand-dug wells indicate local potentiometric surfaces, hence, showed local groundwater flow system which is possibly controlled by the underlying low permeable aquicludes formed by shales. The protective capacity of the aquitards was somewhat reduced by the permeating fractures which exposed the aquifers to polluting effects of mineralized water-types.

  12. Status and understanding of groundwater quality in the South Coast Interior groundwater basins, 2008: California GAMA Priority Basin Project

    Science.gov (United States)

    Parsons, Mary C.; Kulongoski, Justin T.; Belitz, Kenneth

    2014-01-01

    Groundwater quality in the approximately 653-square-mile (1,691-square-kilometer) South Coast Interior Basins (SCI) study unit was investigated as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The South Coast Interior Basins study unit contains eight priority groundwater basins grouped into three study areas, Livermore, Gilroy, and Cuyama, in the Southern Coast Ranges hydrogeologic province. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory. The GAMA South Coast Interior Basins study was designed to provide a spatially unbiased assessment of untreated (raw) groundwater quality within the primary aquifer system, as well as a statistically consistent basis for comparing water quality between basins. The assessment was based on water-quality and ancillary data collected by the USGS from 50 wells in 2008 and on water-quality data from the California Department of Public Health (CDPH) database. The primary aquifer system was defined by the depth intervals of the wells listed in the CDPH database for the SCI study unit. The quality of groundwater in the primary aquifer system may be different from that in the shallower or deeper water-bearing zones; shallow groundwater may be more vulnerable to surficial contamination. The first component of this study, the status of the current quality of the groundwater resource, was assessed by using data from samples analyzed for volatile organic compounds (VOCs), pesticides, and naturally occurring inorganic constituents, such as trace elements and minor ions. This status assessment is intended to characterize the quality of groundwater resources within the primary aquifer system of the SCI study unit, not the treated drinking water delivered to consumers by water purveyors. Relative-concentrations (sample concentration

  13. Assessment of undiscovered oil and gas resources in the Ventura Basin Province, California, 2016

    Science.gov (United States)

    Tennyson, Marilyn E.; Schenk, Christopher J.; Pitman, Janet K.; Lillis, Paul G.; Klett, Timothy R.; Brownfield, Michael E.; Finn, Thomas M.; Gaswirth, Stephanie B.; Hawkins, Sarah J.; Marra, Kristen R.; Mercier, Tracey J.; Le, Phuong A.; Leathers-Miller, Heidi M.

    2017-10-02

    The U.S. Geological Survey (USGS) completed a geology-based assessment of undiscovered, technically recoverable conventional and continuous oil and gas resources in the part of the Ventura Basin Province that lies onshore or within State waters (within 3 miles of the shoreline) of California (fig. 1). Conventional oil and gas resources are those that have migrated upward into structural or stratigraphic traps from deep zones where the oil and gas is generated; water is present below the oil or gas. Continuous accumulations, in contrast, are those in which oil or gas is pervasively present in essentially all wells that penetrate them, that may not be structurally or stratigraphically trapped, and that typically lack oil-water or gas-water contacts. They are commonly produced with well-stimulation technology, such as hydraulic fracturing, referred to as “unconventional.” The same stimulation technology, however, is also used in many conventionally trapped accumulations. We estimated both the likely range of oil and gas volumes remaining to be discovered in accumulations similar to existing conventional oil and gas fields in the Ventura Basin Province (previously assessed by Keller [1995] as 1,060 million barrels of oil [MMBO], 1,900 billion cubic feet of gas [BCFG], and 60 million barrels of natural gas liquids [MMBNGL]), and the potential for oil and gas that might be present in a continuous accumulation at extreme depth in the floor of the basin.

  14. Status of groundwater quality in the California Desert Region, 2006-2008: California GAMA Priority Basin Project

    Science.gov (United States)

    Dawson, Barbara J. Milby; Belitz, Kenneth

    2012-01-01

    Groundwater quality in six areas in the California Desert Region (Owens, Antelope, Mojave, Coachella, Colorado River, and Indian Wells) was investigated as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory. The six Desert studies were designed to provide a spatially unbiased assessment of the quality of untreated groundwater in parts of the Desert and the Basin and Range hydrogeologic provinces, as well as a statistically consistent basis for comparing groundwater quality to other areas in California and across the Nation. Samples were collected by the USGS from September 2006 through April 2008 from 253 wells in Imperial, Inyo, Kern, Los Angeles, Mono, Riverside, and San Bernardino Counties. Two-hundred wells were selected using a spatially distributed, randomized grid-based method to provide a spatially unbiased representation of the study areas (grid wells), and fifty-three wells were sampled to provide additional insight into groundwater conditions (additional wells). The status of the current quality of the groundwater resource was assessed based on data from samples analyzed for volatile organic compounds (VOCs), pesticides, and inorganic constituents such as major ions and trace elements. Water-quality data from the California Department of Public Health (CDPH) database also were incorporated in the assessment. The status assessment is intended to characterize the quality of untreated groundwater resources within the primary aquifer systems of the Desert Region, not the treated drinking water delivered to consumers by water purveyors. The primary aquifer systems (hereinafter, primary aquifers) in the six Desert areas are defined as that part of the aquifer corresponding to the perforation intervals of

  15. Past and future changes of streamflow in Poyang Lake Basin, Southeastern China

    Directory of Open Access Journals (Sweden)

    S. L. Sun

    2012-07-01

    Full Text Available To understand the causes of the past water cycle variations and the influence of climate variability on the streamflow, lake storage, and flood potential, we analyze the changes in streamflow and the underlying drivers in four typical watersheds (Gaosha, Meigang, Saitang, and Xiashan within the Poyang Lake Basin, based on the meteorological observations at 79 weather stations, and datasets of streamflow and river level at four hydrological stations for the period of 1961-2000. The contribution of different climate factors to the change in streamflow in each watershed is estimated quantitatively using the water balance equations. Results show that in each watershed, the annual streamflow exhibits an increasing trend from 1961–2000. The increases in streamflow by 4.80 m3 s−1 yr−1 and 1.29 m3 s−1 yr−1 at Meigang and Gaosha, respectively, are statistically significant at the 5% level. The increase in precipitation is the biggest contributor to the streamflow increment in Meigang (3.79 m3 s−1 yr−1, Gaosha (1.12 m3 s−1 yr−1, and Xiashan (1.34 m3 s−1 yr−1, while the decrease in evapotranspiration is the major factor controlling the streamflow increment in Saitang (0.19 m3 s−1 yr−1. In addition, radiation and wind contribute more than actual vapor pressure and mean temperature to the changes in evapotranspiration and streamflow for the four watersheds.

    For revealing the possible change of streamflow due to the future climate change, we also investigate the projected precipitation and evapotranspiration from of the Coupled Model Intercomparison Project phase 3 (CMIP3 under three greenhouse gases emission scenarios (SRESA1B, SRESA2 and SRESB1 for the period of 2061–2100. When the future changes in the soil water storage

  16. Quantifying the Forcing Factors Responsible for the Tectono-Geomorphological Evolution of Neogene Rift Basins, Baja California

    Science.gov (United States)

    El-Sobky, H. F.; Dorobek, S. L.

    2005-12-01

    The Gulf of California and its surrounding land areas provide a classic example of recently rifted continental lithosphere, where back-arc stretching of a continental volcanic arc has culminated in the ongoing seafloor spreading that characterizes the present-day axis of the gulf. The recent tectonic history of eastern Baja California, which includes most of the land area eastward of the main drainage divide that extends north-south along the length of the peninsula, has been dominated by oblique rifting that began at about 5 Ma. Thus, extensional tectonics, bedrock lithology, long-term climatic changes, and evolving surface processes have controlled the tectono-geomorphological evolution of the eastern part of the peninsula since 5 Ma. No previous studies, however, examined the effect of these combined factors on the current tectono-geomorphological characteristics of eastern Baja California. We assume that although long-term climate may have changed along the peninsula over the last several million years, precipitation amounts are likely to have changed in a similar way along the entire length of the peninsula, regardless of the long-term climatic trend. This suggests that climatic variation can be largely ruled out as an explanation for the geomorphologic variability between basins. In an attempt to quantify the factors that affected the geomorphologic development along the eastern side of Baja California, thirty-four drainage basins were extracted from a 15-m-resolution absolute digital elevation model (DEM). The stacked-vector method was applied to utilize the different terrain attributes (e.g., hillshaded relief, aspect, slope, etc.) for supervised classification of bedrock lithologies using object-oriented techniques. Stream-length gradient indices were then measured for the main stream in each of the basins. Bedrock lithologies and alluvium were plotted along the stream profiles to identify any relationship between lithology, structure, and stream gradient

  17. Integrated risk assessment for the natomas basin (California) analysis of loss of life and emergency management for floods

    NARCIS (Netherlands)

    Jonkman, S.N.; Hiel, L.A.; Bea, R.G.; Foster, H.; Tsioulou, A.; Arroyo, P.; Stallard, T.; Harris, L.

    2012-01-01

    This article assesses the risk to life for the Natomas Basin, a low-lying, rapidly urbanizing region in the Sacramento-San Joaquin Delta in California. Using an empirical method, the loss of life is determined for a flood (high water), seismic, and sunny-day levee breach scenario. The analysis

  18. Initiation, evolution and extinction of pull-apart basins: Implications for opening of the Gulf of California

    Science.gov (United States)

    van Wijk, J.; Axen, G.; Abera, R.

    2017-11-01

    We present a model for the origin, crustal architecture, and evolution of pull-apart basins. The model is based on results of three-dimensional upper crustal elastic models of deformation, field observations, and fault theory, and is generally applicable to basin-scale features, but predicts some intra-basin structural features. Geometric differences between pull-apart basins are inherited from the initial geometry of the strike-slip fault step-over, which results from the forming phase of the strike-slip fault system. As strike-slip motion accumulates, pull-apart basins are stationary with respect to underlying basement, and the fault tips propagate beyond the rift basin, increasing the distance between the fault tips and pull-apart basin center. Because uplift is concentrated near the fault tips, the sediment source areas may rejuvenate and migrate over time. Rift flank uplift results from compression along the flank of the basin. With increasing strike-slip movement the basins deepen and lengthen. Field studies predict that pull-apart basins become extinct when an active basin-crossing fault forms; this is the most likely fate of pull-apart basins, because basin-bounding strike-slip systems tend to straighten and connect as they evolve. The models show that larger length-to-width ratios with overlapping faults are least likely to form basin-crossing faults, and pull-apart basins with this geometry are thus most likely to progress to continental rupture. In the Gulf of California, larger length-to-width ratios are found in the southern Gulf, which is the region where continental breakup occurred rapidly. The initial geometry in the northern Gulf of California and Salton Trough at 6 Ma may have been one of widely-spaced master strike-slip faults (lower length-to-width ratios), which our models suggest inhibits continental breakup and favors straightening of the strike-slip system by formation of basin-crossing faults within the step-over, as began 1.2 Ma when the

  19. Near-vertical seismic reflection image using a novel acquisition technique across the Vrancea Zone and Foscani Basin, south-eastern Carpathians (Romania)

    Science.gov (United States)

    Panea, I.; Stephenson, R.; Knapp, C.; Mocanu, V.; Drijkoningen, G.; Matenco, L.; Knapp, J.; Prodehl, K.

    2005-12-01

    The DACIA PLAN (Danube and Carpathian Integrated Action on Process in the Lithosphere and Neotectonics) deep seismic sounding survey was performed in August-September 2001 in south-eastern Romania, at the same time as the regional deep refraction seismic survey VRANCEA 2001. The main goal of the experiment was to obtain new information on the deep structure of the external Carpathians nappes and the architecture of Tertiary/Quaternary basins developed within and adjacent to the seismically-active Vrancea zone, including the Focsani Basin. The seismic reflection line had a WNW-ESE orientation, running from internal East Carpathians units, across the mountainous south-eastern Carpathians, and the foreland Focsani Basin towards the Danube Delta. There were 131 shot points along the profile, with about 1 km spacing, and data were recorded with stand-alone RefTek-125s (also known as "Texans"), supplied by the University Texas at El Paso and the PASSCAL Institute. The entire line was recorded in three deployments, using about 340 receivers in the first deployment and 640 receivers in each of the other two deployments. The resulting deep seismic reflection stacks, processed to 20 s along the entire profile and to 10 s in the eastern Focsani Basin, are presented here. The regional architecture of the latter, interpreted in the context of abundant independent constraint from exploration seismic and subsurface data, is well imaged. Image quality within and beneath the thrust belt is of much poorer quality. Nevertheless, there is good evidence to suggest that a thick (˜10 km) sedimentary basin having the structure of a graben and of indeterminate age underlies the westernmost part of the Focsani Basin, in the depth range 10-25 km. Most of the crustal depth seismicity observed in the Vrancea zone (as opposed to the more intense upper mantle seismicity) appears to be associated with this sedimentary basin. The sedimentary successions within this basin and other horizons

  20. The supra-detachment tectono-sedimentary record of rifted margins: the example of the Los Barriles Basin, SE Baja California Sur.

    Science.gov (United States)

    Masini, Emmanuel; Robin, Cécile; Geoffroy, Laurent; Strzerzynski, Pierre

    2010-05-01

    The study of rifted margins have shown that the main controlling structures are changing from classical high-angle faults to low-angle detachment fault dominated extension when the crust thins to less than 10 km, which is the case in hyper-extended, magma-poor rifted margins. While the stratigraphic record related to classical high-angle faulting is well constrained, little is known about the tectono-sedimentary evolution of hyper-extended rift systems. A major question remains, how supra-detachment tectono-sedimentary systems are recorded in the stratigraphic record? This remains largely unexplored and must be better constrained by observations. In our poster, we present preliminary results from our study of a rift basin floored by a low-angle detachment system exposed at the southeastern edge of the Baja California Peninsula in the so-called Los Barriles area in the Gulf of California. This area represents one of the best examples of an active transtensional rift system from which the tectono-sedimentary evolution of the rift to drift transition can be studied in the field. The syn-tectonic sedimentary sequence is floored by a detachment fault and is limited oceanward by an extensional allochthon. The syn- to post-tectonic stratigraphy can be summarized into 4 main formations: (1) The Pescadero fluvial fm. (no available ages) evolves upsection from poorly organized polymictic in components and faulted breccias to more granitic and stratified conglomerates. It overlies the extensional allochthon and is tilted continentwards. The channel incisions show EW paleoflows and the upper Pescadero fm. is transitional to the following Refugio fm. (2) The overlying Refugio fm. (Lower Pliocene) occurs as thick marine sandy deposits within the basin axis, is granitic in composition and has average paleocurrents directions trending N-S. The upper part of the fm. is transitional to the following Barriles fm. (3) The Barriles fm. (Upper Miocene - Lower Pleistocene) occurs as very

  1. Comparison of Three Key Marine Shale Reservoirs in the Southeastern Margin of the Sichuan Basin, SW China

    Directory of Open Access Journals (Sweden)

    Jun Liu

    2017-09-01

    Full Text Available This study performs a comprehensive comparison of three key marine shale reservoirs in the southeastern margin of the Sichuan Basin, and explains why commercial gas production was only achieved in the Lower Silurian Longmaxi (LSL and Upper Ordovician Wufeng (UOW formations, but not in the Lower Cambrian Niutitang (LCN formation. The experimental methods included in situ gas content and gas composition tests, methane adsorption analysis, low-pressure N2 adsorption, field emission scanning electron microscopy (FE-SEM, and total organic carbon (TOC and vitrinite reflectance (Ro analyses to evaluate the lithology, mineralogy, physical properties of the reservoir, organic geochemistry, in situ gas content and methane adsorption capacity characteristics of the three shales. The LCN shale has lower quartz and clay mineral contents and a low brittleness index, but higher contents of feldspar, pyrite and carbonate minerals than the LSL and UOW shales. The porosity and permeability of the LSL and UOW shales are higher than those of the LCN shale. The primary contributions to the high permeability in the LSL shale are its well-developed fractures and organic matter pores. In contrast, the over-mature LCN shale is unfavorable for the development of organic pores and fractures. Although the LCN shale has a higher methane sorption capacity than the LSL and UOW shales, the gas content and methane saturation of the LCN shale are distinctly lower than those of the LSL and UOW shales. This is primarily due to gas migration from the LCN shale, resulting from the activities of tectonic uplift and the unconformable contact between the LCN shale and the Dengying formation. When compared with gas shale in North America, the LSL shale is the most favorable shale reservoir out of the three Sichuan shales, while the combination of the LSL and UOW shales is also potentially productive. However, the individual single layer production of the UOW or LCN shales is still

  2. LLWPA: Implementation in California

    International Nuclear Information System (INIS)

    Gaynor, R.K.; Romano, S.A.

    1987-01-01

    US Ecology has been designated by the State of California to locate, develop and operate a low-level radioactive waste disposal facility. In early 1986, the firm identified eighteen desert basins in southeastern California for siting considerations. Three candidate sites were selected for detailed field characterization work in February, 1987. A preferred site for licensing purposes will be identified in late 1987. California is currently ahead of the siting milestone schedule mandated by the Low-Level Radioactive Waste Policy Amendments Act. It is likely that a license application will be filed in mid-1988, well before the 1990 milestone date. It is anticipated that the site will be constructed around that milestone date. This paper describes the process undertaken by US Ecology to identify three candidate sites for characterization, and the public involvement program supporting this decision. Future activities leading to a final site development are also described

  3. Coccolithophore response to climate and surface hydrography in Santa Barbara Basin, California, AD 1917–2004

    Directory of Open Access Journals (Sweden)

    M. Grelaud

    2009-10-01

    Full Text Available The varved sedimentary AD 1917–2004 record from the depositional center of the Santa Barbara Basin (SBB, California was analyzed with monthly to triannual resolution to yield relative abundances of six coccolithophore species representing at least 96% of the coccolithophore assemblage. Seasonal/annual relative abundances respond to climatic and surface hydrographic conditions in the SBB, whereby (i the three species G. oceanica, H. carteri and F. profunda are characteristic of the strength of the northward flowing warm California Counter Current, (ii the two species G. ericsonii and G. muellerae are associated with the cold equatorward flowing California Current, (iii and E. huxleyi appears to be endemic to the SBB. Spectral analyses on relative abundances of these species show that all are influenced by the El Niño Southern Oscillation (ENSO and/or by the Pacific Decadal Oscillation (PDO. Increased relative abundances of G. oceanica and H. carteri are associated with warm ENSO events, G. muellerae responds to warm PDO events and the abundance of G. ericsonii increases during cold PDO events. Morphometric parameters measured on E. huxleyi, G. muellerae and G. oceanica indicate increasing coccolithophore shell carbonate mass from ~1917 until 2004 concomitant with rising pCO2 and sea surface temperature in the region of the SBB.

  4. Seismicity and focal mechanisms for the southern Great Basin of Nevada and California: 1987 through 1989

    Energy Technology Data Exchange (ETDEWEB)

    Harmsen, S.C.; Bufe, C.G.

    1991-12-31

    For the calendar year 1987, the southern Great basin seismic network (SGBSN) recorded about 820 earthquakes in the southern Great Basin (SGB). Local magnitudes ranged from 0.2 to 4.2 (December 30, 1987, 22:50:42 UTC at Hot Creek Valley). Five earthquakes epicenters in 1987 within the detection threshold of the seismic network are at Yucca Mountain, the site of a potential national, high-level nuclear waste repository. The maximum magnitude of those five earthquakes is 1.1, and their estimated depths of focus ranged from 3.1 to 7.6 km below sea level. For the calendar year 1988, about 1280 SGB earthquakes were catalogued, with maximum magnitude-4.4 for an Owens Valley, California, earthquake on July 5, 1988. Eight earthquake epicenters in 1988 are at Yucca Mountain, with depths ranging from three to 12 km below sea level, and maximum magnitude 2.1. For the calendar year 1989, about 1190 SGB earthquakes were located and catalogued, with maximum magnitude equal to 3.5 for earthquake about ten miles north of Las Vegas, Nevada, on January 9. No Yucca Mountain earthquakes were recorded in 1989. An earthquake having a well-constrained depth of about 30 km below sea level was observed on August 21, 1989, in eastern Nevada Test Site (NTS).

  5. Fluid geochemistry of cold seeps and hydrothermal vents in the Guaymas Basin, Gulf of California

    Science.gov (United States)

    Hensen, Christian; Geilert, Sonja; Scholz, Florian; Schmidt, Mark; Liebetrau, Volker; Kipfer, Rolf; Sarkar, Sudipta; Doll, Mechthild

    2017-04-01

    has ceased and biogenically formed methane migrates upward along pre-existing fluid pathways. Berndt, C., Hensen, C., Mortera-Gutierrez, C., Sarkar, S., Geilert, S., Schmidt, M., Liebetrau, V., Kipfer, R., Scholz, F., Doll, M., Muff, S., Karstens, J., Planke, S., Petersen, S., Böttner, C., Chi, W.-C., Moser, M., Behrendt, R., Fiskal, A., Lever, M.A., Su, C.-C., Deng, L., Brennwald, M.S. and Lizarralde, D. (2016) Rifting under steam -How rift magmatism triggers methane venting from sedimentary basins. Geology 44, 767-770. Lupton, J.E. (1979) Helium-3 in the Guaymas Basin: Evidence for injection of mantle volatiles in the Gulf of California: Journal of Geophysical Research, v. 84, p. 7446-7452.

  6. Observations of basin ground motions from a dense seismic array in San Jose, California

    Science.gov (United States)

    Frankel, A.; Carver, D.; Cranswick, E.; Bice, T.; Sell, R.; Hanson, S.

    2001-01-01

    We installed a dense array of 41 digital seismographs in San Jose, California, to evaluate in detail the effects of a deep sedimentary basin and shallow sedimentary deposits on earthquake ground motions. This urban array is located near the eastern edge of the Santa Clara Valley and spans the Evergreen sedimentary basin identified by gravity data. Average station spacing is 1 km, with three stations initially spaced 110 m apart. Despite the high-noise urban environment, the stations of the array successfully triggered on and recorded small local earthquakes (M 2.5-2.8 at 10-25 km distance) and larger regional events such as the M 5.0 Bolinas earthquake (90 km distance), M 4.6-5.6 earthquakes near Mammoth Lakes (270 km distance), M 4.9-5.6 events in western Nevada (420 km distance) and the M 7.1 Hector Mine earthquake (590 km distance). Maps of spectral ratios across the array show that the highest amplitudes in all frequency bands studied (0.125-8 Hz) are generally observed at stations farther from the eastern edge of the Santa Clara Valley. Larger spectral amplitudes are often observed above the western edge of the Evergreen Basin. Snapshots of the recorded wavefield crossing the array for regional events to the east reveal that large, low-frequency (0.125-0.5 Hz) arrivals after the S-wave travel from south to north across the array. A moving-window, cross-correlation analysis finds that these later arrivals are surface waves traveling from the south. The timing and propagation direction of these arrivals indicates that they were likely produced by scattering of incident S waves at the border of the Santa Clara Valley to the south of the array. It is remarkable that the largest low-frequency phases at many of the valley sites for regional events to the east are basin surface waves coming from a direction about 70 degrees different from that of the epicenters. Basin surface waves emanating from the eastern edge of the valley are also identified by the cross

  7. Seismic site characterization of an urban dedimentary basin, Livermore Valley, California: Site tesponse, basin-edge-induced surface waves, and 3D simulations

    Science.gov (United States)

    Hartzell, Stephen; Leeds, Alena L.; Ramirez-Guzman, Leonardo; Allen, James P.; Schmitt, Robert G.

    2016-01-01

    Thirty‐two accelerometers were deployed in the Livermore Valley, California, for approximately one year to study sedimentary basin effects. Many local and near‐regional earthquakes were recorded, including the 24 August 2014 Mw 6.0 Napa, California, earthquake. The resulting ground‐motion data set is used to quantify the seismic response of the Livermore basin, a major structural depression in the California Coast Range Province bounded by active faults. Site response is calculated by two methods: the reference‐site spectral ratio method and a source‐site spectral inversion method. Longer‐period (≥1  s) amplification factors follow the same general pattern as Bouguer gravity anomaly contours. Site response spectra are inverted for shallow shear‐wave velocity profiles, which are consistent with independent information. Frequency–wavenumber analysis is used to analyze plane‐wave propagation across the Livermore Valley and to identify basin‐edge‐induced surface waves with back azimuths different from the source back azimuth. Finite‐element simulations in a 3D velocity model of the region illustrate the generation of basin‐edge‐induced surface waves and point out strips of elevated ground velocities along the margins of the basin.

  8. Airborne electromagnetic data and processing within Leach Lake Basin, Fort Irwin, California: Chapter G in Geology and geophysics applied to groundwater hydrology at Fort Irwin, California

    Science.gov (United States)

    Bedrosian, Paul A.; Ball, Lyndsay B.; Bloss, Benjamin R.

    2014-01-01

    From December 2010 to January 2011, the U.S. Geological Survey conducted airborne electromagnetic and magnetic surveys of Leach Lake Basin within the National Training Center, Fort Irwin, California. These data were collected to characterize the subsurface and provide information needed to understand and manage groundwater resources within Fort Irwin. A resistivity stratigraphy was developed using ground-based time-domain electromagnetic soundings together with laboratory resistivity measurements on hand samples and borehole geophysical logs from nearby basins. This report releases data associated with the airborne surveys, as well as resistivity cross-sections and depth slices derived from inversion of the airborne electromagnetic data. The resulting resistivity models confirm and add to the geologic framework, constrain the hydrostratigraphy and the depth to basement, and reveal the distribution of faults and folds within the basin.

  9. Groundwater quality in the Monterey Bay and Salinas Valley groundwater basins, California

    Science.gov (United States)

    Kulongoski, Justin T.; Belitz, Kenneth

    2011-01-01

    The Monterey-Salinas study unit is nearly 1,000 square miles and consists of the Santa Cruz Purisima Formation Highlands, Felton Area, Scotts Valley, Soquel Valley, West Santa Cruz Terrace, Salinas Valley, Pajaro Valley, and Carmel Valley groundwater basins (California Department of Water Resources, 2003; Kulongski and Belitz, 2011). These basins were grouped into four study areas based primarily on geography. Groundwater basins in the north were grouped into the Santa Cruz study area, and those to the south were grouped into the Monterey Bay, the Salinas Valley, and the Paso Robles study areas (Kulongoski and others, 2007). The study unit has warm, dry summers and cool, moist winters. Average annual rainfall ranges from 31 inches in Santa Cruz in the north to 13 inches in Paso Robles in the south. The study areas are drained by several rivers and their principal tributaries: the Salinas, Pajaro, and Carmel Rivers, and San Lorenzo Creek. The Salinas Valley is a large intermontane valley that extends southeastward from Monterey Bay to Paso Robles. It has been filled, up to a thickness of 2,000 feet, with Tertiary and Quaternary marine and terrestrial sediments that overlie granitic basement. The Miocene-age Monterey Formation and Pliocene- to Pleistocene-age Paso Robles Formation, and Pleistocene to Holocene-age alluvium contain freshwater used for supply. The primary aquifers in the study unit are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells are typically drilled to depths of 200 to 650 feet, consist of solid casing from the land surface to depths of about 175 to 500 feet, and are perforated below the solid casing. Water quality in the primary aquifers may differ from that in the shallower and deeper parts of the aquifer system. Groundwater movement is generally from the southern part of the Salinas Valley north towards the Monterey Bay

  10. Characteristics of source rocks of the Datangpo Fm, Nanhua System, at the southeastern margin of Sichuan Basin and their significance to oil and gas exploration

    Directory of Open Access Journals (Sweden)

    Zengye Xie

    2017-11-01

    Full Text Available In recent years, much attention has been paid to the development environment, biogenetic compositions and hydrocarbon generation characteristics of ancient source rocks in the deep strata of the Sichuan Basin because oil and gas exploration extends continuously to the deep and ultra-deep strata and a giant gas field with the explored reserves of more than 1 × 1012 m3 was discovered in the Middle and Upper Proterozoic–Lower Paleozoic strata in the stable inherited paleo-uplift of the central Sichuan Basin. Based on the previous geological research results, outcrop section of the Datangpo Fm, Nanhua System, at the southeastern margin of the Sichuan Basin was observed and the samples taken from the source rocks were tested and analyzed in terms of their organic geochemistry and organic petrology. It is shown that high-quality black shale source rocks of the Datangpo Fm are developed in the tensional background at the southeastern margin of the Sichuan Basin between two glacial ages, i.e., Gucheng and Nantuo ages in the Nanhua Period. Their thickness is 16–180 m and mineral compositions are mainly clay minerals and clastic quartz. Besides, shale in the Datangpo Fm is of high-quality sapropel type source rock with high abundance at an over-mature stage, and it is characterized by low pristane/phytane ratios (0.32–0.83, low gammacerane abundance, high-abundance tricyclic terpane and higher-content C27 and C29 gonane, indicating that biogenetic compositions are mainly algae and microbes in a strong reducing environment with low salinity. It is concluded that the Datangpo Fm source rocks may be developed in the rift of Nanhua System in central Sichuan Basin. Paleo-uplifts and paleo-slopes before the Caledonian are the favorable locations for the accumulation of dispersed liquid hydrocarbons and paleo-reservoirs derived from the Datangpo Fm source rocks. In addition, scale accumulation zones of dispersed organic matter cracking gas and paleo

  11. Precipitation-runoff processes in the Feather River basin, northeastern California, and streamflow predictability, water years 1971-97

    Science.gov (United States)

    Koczot, Kathryn M.; Jeton, Anne E.; McGurk, Bruce; Dettinger, Michael D.

    2005-01-01

    Precipitation-runoff processes in the Feather River Basin of northern California determine short- and long-term streamflow variations that are of considerable local, State, and Federal concern. The river is an important source of water and power for the region. The basin forms the headwaters of the California State Water Project. Lake Oroville, at the outlet of the basin, plays an important role in flood management, water quality, and the health of fisheries as far downstream as the Sacramento-San Joaquin Delta. Existing models of the river simulate streamflow in hourly, daily, weekly, and seasonal time steps, but cannot adequately describe responses to climate and land-use variations in the basin. New spatially detailed precipitation-runoff models of the basin have been developed to simulate responses to climate and land-use variations at a higher spatial resolution than was available previously. This report characterizes daily rainfall, snowpack evolution, runoff, water and energy balances, and streamflow variations from, and within, the basin above Lake Oroville. The new model's ability to predict streamflow is assessed. The Feather River Basin sits astride geologic, topographic, and climatic divides that establish a hydrologic character that is relatively unusual among the basins of the Sierra Nevada. It straddles a north-south geologic transition in the Sierra Nevada between the granitic bedrock that underlies and forms most of the central and southern Sierra Nevada and volcanic bedrock that underlies the northernmost parts of the range (and basin). Because volcanic bedrock generally is more permeable than granitic, the northern, volcanic parts of the basin contribute larger fractions of ground-water flow to streams than do the southern, granitic parts of the basin. The Sierra Nevada topographic divide forms a high altitude ridgeline running northwest to southeast through the middle of the basin. The topography east of this ridgeline is more like the rain

  12. Groundwater simulation and management models for the upper Klamath Basin, Oregon and California

    Science.gov (United States)

    Gannett, Marshall W.; Wagner, Brian J.; Lite, Kenneth E.

    2012-01-01

    The upper Klamath Basin encompasses about 8,000 square miles, extending from the Cascade Range east to the Basin and Range geologic province in south-central Oregon and northern California. The geography of the basin is dominated by forested volcanic uplands separated by broad interior basins. Most of the interior basins once held broad shallow lakes and extensive wetlands, but most of these areas have been drained or otherwise modified and are now cultivated. Major parts of the interior basins are managed as wildlife refuges, primarily for migratory waterfowl. The permeable volcanic bedrock of the upper Klamath Basin hosts a substantial regional groundwater system that provides much of the flow to major streams and lakes that, in turn, provide water for wildlife habitat and are the principal source of irrigation water for the basin's agricultural economy. Increased allocation of surface water for endangered species in the past decade has resulted in increased groundwater pumping and growing interest in the use of groundwater for irrigation. The potential effects of increased groundwater pumping on groundwater levels and discharge to springs and streams has caused concern among groundwater users, wildlife and Tribal interests, and State and Federal resource managers. To provide information on the potential impacts of increased groundwater development and to aid in the development of a groundwater management strategy, the U.S. Geological Survey, in collaboration with the Oregon Water Resources Department and the Bureau of Reclamation, has developed a groundwater model that can simulate the response of the hydrologic system to these new stresses. The groundwater model was developed using the U.S. Geological Survey MODFLOW finite-difference modeling code and calibrated using inverse methods to transient conditions from 1989 through 2004 with quarterly stress periods. Groundwater recharge and agricultural and municipal pumping are specified for each stress period. All

  13. Status and understanding of groundwater quality in the Monterey Bay and Salinas Valley Basins, 2005-California GAMA Priority Basin Project

    Science.gov (United States)

    Kulongoski, Justin T.; Belitz, Kenneth

    2011-01-01

    Groundwater quality in the approximately 1,000 square mile (2,590 km2) Monterey Bay and Salinas Valley Basins (MS) study unit was investigated as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study unit is located in central California in Monterey, Santa Cruz, and San Luis Obispo Counties. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory. The GAMA MS study was designed to provide a spatially unbiased assessment of the quality of untreated (raw) groundwater in the primary aquifer systems (hereinafter referred to as primary aquifers). The assessment is based on water-quality and ancillary data collected in 2005 by the USGS from 97 wells and on water-quality data from the California Department of Public Health (CDPH) database. The primary aquifers were defined by the depth intervals of the wells listed in the CDPH database for the MS study unit. The quality of groundwater in the primary aquifers may be different from that in the shallower or deeper water-bearing zones; shallow groundwater may be more vulnerable to surficial contamination. The first component of this study, the status of the current quality of the groundwater resource, was assessed by using data from samples analyzed for volatile organic compounds (VOC), pesticides, and naturally occurring inorganic constituents, such as major ions and trace elements. This status assessment is intended to characterize the quality of groundwater resources in the primary aquifers of the MS study unit, not the treated drinking water delivered to consumers by water purveyors. Relative-concentrations (sample concentration divided by the health- or aesthetic-based benchmark concentration) were used for evaluating groundwater quality for those constituents that have Federal and (or) California regulatory or

  14. Geohydrology and water quality of stratified-drift aquifers in the lower Merrimack and coastal river basins, southeastern New Hampshire

    Science.gov (United States)

    Stekl, Peter J.; Flanagan, Sarah M.

    1992-01-01

    Communities in the lower Merrimack River basin and coastal river basins of southeastern New Hampshire are experiencing increased demands for water because of a rapid increase in population. The population in 1987 was 225,495 and is expected to increase by 30 percent during the next decade. As of 1987, five towns used the stratified-drift aquifers for municipal supply and withdrew an estimated 6 million gallons per day. Four towns used the bedrock aquifer for municipal supply and withdrew an average of 1 .6 million gallons per day. Stratified-drift deposits cover 78 of the 327 square miles of the study area. These deposits are generally less than 10 square miles in areal extent, and their saturated thickness ranges front less than 20 feet to as much as 100 feet . Transinissivity exceeds 4,000 square feet per day in several locations. Stratified-drift aquifers in the eastern part are predominantly small ice-contact deposits surrounded by marine sediments or till of low hydraulic conductivity. Stratified-drift aquifers in the western part consist of ice-contact and proglacial deposits that are large in areal extent and are commonly in contact with surface-water bodies. Five stratified-drift aquifers, in the towns of Derry, Windham, Kingston, North Hampton, and Greenland, have the greatest potential to supply additional amounts of water. Potential yields and contributing areas of hypothetical supply wells were estimated for an aquifer in Windham near Cobbetts Pond and for an aquifer in Kingston along the Powwow River by use of a method analogous to superposition in conjunction with a numerical ground-waterflow model. The potential yield is estimated to be 0 .6 million gallons per day for the Windham-Cobbetts Pond aquifer and 4 .0 million gallons per day for the Kingston-Powwow River aquifer. Contributing recharge area for supply wells is estimated to be 1.6 square miles in the Windham-Cobbetts Pond aquifer and 4.9 square miles in the Kingston-Powwow River aquifer

  15. Subsidence of the Laguna Salada Basin, northeastern Baja California, Mexico, inferred from Milankovitch climatic changes

    Energy Technology Data Exchange (ETDEWEB)

    Contreras, Juan; Martin-Barajas, Arturo [Departamento de Geologia, CICESE, Ensenada Baja California (Mexico); Herguera, Juan Carlos [Division de Oceanologia, CICESE, Ensenada Baja California (Mexico)

    2005-01-15

    Laguna Salada in northern Baja California, Mexico, is an active half-graben product of the trans-tensional tectonics of the Gulf of California. It is sensitive to changes in sediment supply from the Colorado River basin. We present a time series analysis of the upper 980 m of a gamma-ray log from a borehole drilled near the Laguna Salada fault. The power spectrum of the gammaray log resembles the spectrum of {delta}{sup 1}8{omicron} Pleistocene isotopic variations from ice cores and from the deep ocean, known to be strongly controlled by Milankovitch cycles. We correlate {delta}{sup 1}8{omicron} stages with silty and sandy intervals in the log. Downcore ages for the last 780 ky are constrained within {approx}10 kyr. We derive a simple time vs. depth calibration relation for the basin over this time interval. Estimated sedimentation rates at the drill site appear to be constant with a value of {approx}1.6 mm/yr. We propose that this subsidence rate is produced by the Laguna Salada fault. [Spanish] La cuenca de Laguna Salada en el norte de Baja California, Mexico, es un semigraben activo producto de la tectonica ranstensional del Golfo de California. Esta cuenca endorreica es sensible a cambios en sedimentacion por variaciones en el aporte e sedimentos de fuentes cercanas y distales transportados por arroyos de las sierras adyacentes y por el Rio Colorado. Esta cuenca es un sitio excepcional para explorar el uso de cambios climaticos ciclicos como herramienta de datacion y estimar tasas de sedimentacion y subsidencia en el area. Para demostrar esto se presenta un analisis de series de tiempo de un registro de rayos de gama de un pozo geotermico exploratorio perforado adyacente a la falla de Laguna Salada, la cual limita el margen oriental de la cuenca. Los resultados del analisis indican que el espectro de los primeros 980 m del registro de rayos gama tiene una alta coherencia con el espectro de registros isotopicos paleoclimaticos de {delta}{sup 1}8{omicron} del

  16. Status of groundwater quality in the Santa Barbara Study Unit, 2011: California GAMA Priority Basin Project

    Science.gov (United States)

    Davis, Tracy A.; Kulongoski, Justin T.

    2016-10-03

    Groundwater quality in the 48-square-mile Santa Barbara study unit was investigated in 2011 as part of the California State Water Resources Control Board’s Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Project. The study unit is mostly in Santa Barbara County and is in the Transverse and Selected Peninsular Ranges hydrogeologic province. The GAMA Priority Basin Project is carried out by the U.S. Geological Survey in collaboration with the California State Water Resources Control Board and Lawrence Livermore National Laboratory.The GAMA Priority Basin Project was designed to provide a statistically unbiased, spatially distributed assessment of the quality of untreated groundwater in the primary aquifer system of California. The primary aquifer system is defined as that part of the aquifer corresponding to the perforation interval of wells listed in the California Department of Public Health database for the Santa Barbara study unit. This status assessment is intended to characterize the quality of groundwater resources in the primary aquifer system of the Santa Barbara study unit, not the treated drinking water delivered to consumers by water purveyors.The status assessment for the Santa Barbara study unit was based on water-quality and ancillary data collected in 2011 by the U.S. Geological Survey from 23 sites and on water-quality data from the California Department of Public Health database for January 24, 2008–January 23, 2011. The data used for the assessment included volatile organic compounds; pesticides; pharmaceutical compounds; two constituents of special interest, perchlorate and N-nitrosodimethylamine (NDMA); and naturally present inorganic constituents, such as major ions and trace elements. Relative-concentrations (sample concentration divided by the health- or aesthetic-based benchmark concentration) were used to evaluate groundwater quality for those constituents that have federal or California regulatory and non

  17. Synchronous egress and ingress fluid flow related to compressional reactivation of basement faults: the Phoenix and Gryphon uranium deposits, southeastern Athabasca Basin, Saskatchewan, Canada

    Science.gov (United States)

    Li, Zenghua; Chi, Guoxiang; Bethune, Kathryn M.; Eldursi, Khalifa; Thomas, David; Quirt, David; Ledru, Patrick

    2018-02-01

    Previous studies on unconformity-related uranium deposits in the Athabasca Basin (Canada) suggest that egress flow and ingress flow can develop along single fault systems at different stages of compressional deformation. This research aims to examine whether or not both ingress and egress flow can develop at the same time within an area under a common compressional stress field, as suggested by the reverse displacement of the unconformity surface by the basement faults. The study considers the Phoenix and Gryphon uranium deposits in the Wheeler River area in the southeastern part of the Athabasca Basin. Two-dimensional numerical modeling of fluid flow, coupled with compressional deformation and thermal effects, was carried out to examine the fluid flow pattern. The results show that local variations in the basement geology under a common compressional stress field can result in both egress and ingress flow at the same time. The fault zone at Phoenix underwent a relatively low degree of deformation, as reflected by minor reverse displacement of the unconformity, and egress flow developed, whereas the fault zone at Gryphon experienced a relatively high degree of deformation, as demonstrated by significant reverse displacement of the unconformity, and ingress flow was dominant. The correlation between strain development and location of uranium mineralization, as exemplified by Gryphon and Phoenix uranium deposits, suggests that the localization of dilation predicted by numerical modeling may represent favourable sites for uranium mineralization in the Athabasca Basin.

  18. Hydrologic data for the Walker River Basin, Nevada and California, water years 2010–14

    Science.gov (United States)

    Pavelko, Michael T.; Orozco, Erin L.

    2015-12-10

    Walker Lake is a threatened and federally protected desert terminal lake in western Nevada. To help protect the desert terminal lake and the surrounding watershed, the Bureau of Reclamation and U.S. Geological Survey have been studying the hydrology of the Walker River Basin in Nevada and California since 2004. Hydrologic data collected for this study during water years 2010 through 2014 included groundwater levels, surface-water discharge, water chemistry, and meteorological data. Groundwater levels were measured in wells, and surface-water discharge was measured in streams, canals, and ditches. Water samples for chemical analyses were collected from wells, streams, springs, and Walker Lake. Chemical analyses included determining physical properties; the concentrations of major ions, nutrients, trace metals, dissolved gases, and radionuclides; and ratios of the stable isotopes of hydrogen and oxygen. Walker Lake water properties and meteorological parameters were monitored from a floating platform on the lake. Data collection methods followed established U.S. Geological Survey guidelines, and all data are stored in the National Water Information System database. All of the data are presented in this report and accessible on the internet, except multiple-depth Walker Lake water-chemistry data, which are available only in this report.

  19. Pesticides and pesticide degradation products in stormwater runoff: Sacramento River Basin, California

    Science.gov (United States)

    Domagalski, Joseph L.

    1996-01-01

    Pesticides in stormwater runoff, within the Sacramento River Basin, California, were assessed during a storm that occurred in January 1994. Two organophosphate insecticides (diazinon and methidathion), two carbamate pesticides (molinate and carbofuran), and one triazine herbicide (simazine) were detected. Organophosphate pesticide concentrations increased with the rising stage of the hydrographs; peak concentrations were measured near peak discharge. Diazinon oxon, a toxic degradation product of diazinon, made up approximately 1 to 3 percent of the diazinon load. The Feather River was the principal source of organophosphate pesticides to the Sacramento River during this storm. The concentrations of molinate and carbofuran, pesticides applied to rice fields during May and June, were relatively constant during and after the storm. Their presence in surface water was attributed to the flooding and subsequent drainage, as a management practice to degrade rice stubble prior to the next planting. A photodegradation product of molinate, 4-keto molinate, was in all samples where molinate was detected and made up approximately 50 percent of the total molinate load. Simazine, a herbicide used in orchards and to control weeds along the roadways, was detected in the storm runoff, but it was not possible to differentiate the two sources of that pesticide to the Sacramento River.

  20. AUTOCHTHONOUS BIOFACIES IN THE PLIOCENE LORETO BASIN, BAJA CALIFORNIA SUR, MEXICO

    Directory of Open Access Journals (Sweden)

    MICHELE PIAZZA

    1998-07-01

    Full Text Available The present paper examines the molluscan and/or echinoid assemblages recovered from two lithostratigraphic units (Piedras Rodadas Sandstone and Arroyo de Arce Norte Sandstone outcropping in the Pliocene Loreto Basin, Baja California Sur, Mexico. Ten biofacies have been identified, i.e. Trachycardium procerum-Trachycardium senticosum Biofacies, Chione compta-Transennella modesta Biofacies, Laevicardium elenense-Chione kelletii Biofacies, Xenophora sp. 1-Strombus subgracilior Biofacies, Crassostrea californica osunai Biofacies, Myrakeena angelica Biofacies, Vermetid-Nodipecten Biofacies, Argopecten abietis abietis Biofacies, Aequipecten dallasi Biofacies and Encope Biofacies. The first four biofacies have been defined on the basis of statistical analyses (cluster analysis, MDS. The other six, which are monospecific or definitely low-diversity, were already identified during field work. The deduced paleoecological bearing of biofacies, largely relying upon the comparison to their closest modern counterparts, provides the basis for the paleoenvironmental reconstruction. The latter also considers sedimentological evidence and is framed within the tectonic and sedimentary context recently proposed by American workers. Biofacies point toward environments differing in terms of substrate texture, presence/absence of vegetal cover, energy level, variously distributed within the low tide mark-40 m bathymetric range. 

  1. Fault zone characteristics and basin complexity in the southern Salton Trough, California

    Science.gov (United States)

    Persaud, Patricia; Ma, Yiran; Stock, Joann M.; Hole, John A.; Fuis, Gary S.; Han, Liang

    2016-01-01

    Ongoing oblique slip at the Pacific–North America plate boundary in the Salton Trough produced the Imperial Valley (California, USA), a seismically active area with deformation distributed across a complex network of exposed and buried faults. To better understand the shallow crustal structure in this region and the connectivity of faults and seismicity lineaments, we used data primarily from the Salton Seismic Imaging Project to construct a three-dimensional P-wave velocity model down to 8 km depth and a velocity profile to 15 km depth, both at 1 km grid spacing. A VP = 5.65–5.85 km/s layer of possibly metamorphosed sediments within, and crystalline basement outside, the valley is locally as thick as 5 km, but is thickest and deepest in fault zones and near seismicity lineaments, suggesting a causative relationship between the low velocities and faulting. Both seismicity lineaments and surface faults control the structural architecture of the western part of the larger wedge-shaped basin, where two deep subbasins are located. We estimate basement depths, and show that high velocities at shallow depths and possible basement highs characterize the geothermal areas.

  2. Water-quality assessment of the Smith River drainage basin, California and Oregon

    Science.gov (United States)

    Iwatsubo, Rick T.; Washabaugh, Donna S.

    1982-01-01

    A water-quality assessment of the Smith River drainage basin was made to provide a summary of the water-quality conditions including known or potential water-quality problems. Results of the study showed that the water quality of the Smith River is excellent and generally meets the water-quality objectives for the beneficial uses identified by the California Regional Water Quality Control Board, North Coast Region. Known and potential problems related to water quality include: Sedimentation resulting from both natural erosional processes and land-use activities such as timber harvest, road construction, and mining that accelerate the erosional processes; bacterial contamination of surface and ground waters from inundated septic tanks and drainfields, and grazing activities; industrial spills which have resulted in fish kills and oil residues; high concetrations of iron in ground water; log and debris jams creating fish migration barriers; and pesticide and trace-element contamination from timber-harvest and mining activities, respectively. Future studies are needed to establish: (1) a sustained long-term monitoring program to provide a broad coverage of water-quality conditions in order to define long-term water-quality trends; and (2) interpretive studies to determine the source of known and potential water-quality problems. (USGS)

  3. Magnetic investigation and 2½ D gravity profile modelling across the Beattie magnetic anomaly in the southeastern Karoo Basin, South Africa

    Science.gov (United States)

    Baiyegunhi, Christopher; Gwavava, Oswald

    2017-03-01

    The southeastern Karoo Basin is considered to be one of the most prospective areas for shale gas exploration in South Africa. An interesting magnetic anomaly, the Beattie magnetic anomaly (BMA), and geologic intrusions are seen on the magnetic map. To date, the source of the BMA and interconnectivity of the igneous intrusions are not well understood. In this study, we investigate the interconnectivity of the igneous intrusions and possible location of the source of the BMA using gravity and magnetic methods. The gravity model results showed that igneous intrusions are interconnected at depth, which probably pose threat by increasing the risk of fracking the Karoo for shale gas exploration. The magnetic results revealed that the BMA becomes stronger with depth. The average depths to the top of the shallow and deep magnetic sources were estimated to be approximately 0.6 and 15 km, respectively.

  4. Status and understanding of groundwater quality in the central-eastside San Joaquin Basin, 2006: California GAMA Priority Basin Project

    Science.gov (United States)

    Landon, Matthew K.; Belitz, Kenneth; Jurgens, Bryant C.; Kulongoski, Justin T.; Johnson, Tyler D.

    2010-01-01

    Groundwater quality in the approximately 1,695-square-mile Central Eastside San Joaquin Basin (Central Eastside) study unit was investigated as part of the Priority Basin Project (PBP) of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA PBP was developed in response to the California Groundwater Quality Monitoring Act of 2001, and is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey and the Lawrence Livermore National Laboratory. The GAMA Central Eastside study unit was designed to provide a spatially unbiased assessment of untreated-groundwater quality, as well as a statistically consistent basis for comparing water quality throughout California. During March through June 2006, samples were collected from 78 wells in Stanislaus and Merced Counties, 58 of which were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study unit (grid wells), and 20 of which were sampled to evaluate changes in water chemistry along groundwater-flow paths (understanding wells). Water-quality data from the California Department of Public Health (CDPH) database also were used for the assessment.An assessment of the current status of the groundwater quality included collecting samples from wells for analysis of anthropogenic constituents such as volatile organic compounds (VOCs) and pesticides, as well as naturally occurring constituents such as major ions and trace elements. The assessment of status is intended to characterize the quality of untreated-groundwater resources within the primary aquifer system, not the treated drinking water delivered to consumers by water purveyors. The primary aquifer system (hereinafter, primary aquifer) is defined as that part of the aquifer corresponding to the perforation interval of wells listed in the CDPH database for the Central Eastside study unit. The quality of groundwater in shallower or

  5. A new species of palaemonid shrimp, Chacella tricornuta spec. nov (Crustacea: Decapoda: Palaemonidae) from the southeastern Gulf of California, Mexico

    NARCIS (Netherlands)

    Hendrickx, M.E.

    1990-01-01

    A new species of the palaemonid shrimp genus Chacella Bruce is described from the Gulf of California, Mexico, in the eastern Pacific, and represents the second known species of this genus. The type-species, Chacella kerstitchi (Wicksten, 1983), was described from a single female captured off the

  6. Status of groundwater quality in the San Fernando--San Gabriel study unit, 2005--California GAMA Priority Basin Project

    Science.gov (United States)

    Land, Michael; Kulongoski, Justin T.; Belitz, Kenneth

    2012-01-01

    Groundwater quality in the approximately 460-square-mile San Fernando--San Gabriel (FG) study unit was investigated as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study area is in Los Angeles County and includes Tertiary-Quaternary sedimentary basins situated within the Transverse Ranges of southern California. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory. The GAMA FG study was designed to provide a spatially unbiased assessment of the quality of untreated (raw) groundwater in the primary aquifer systems (hereinafter referred to as primary aquifers) throughout California. The assessment is based on water-quality and ancillary data collected in 2005 by the USGS from 35 wells and on water-quality data from the California Department of Public Health (CDPH) database. The primary aquifers were defined by the depth interval of the wells listed in the CDPH database for the FG study unit. The quality of groundwater in primary aquifers may be different from that in the shallower or deeper water-bearing zones; shallow groundwater may be more vulnerable to surficial contamination. This study assesses the status of the current quality of the groundwater resource by using data from samples analyzed for volatile organic compounds (VOCs), pesticides, and naturally occurring inorganic constituents, such as major ions and trace elements. This status assessment is intended to characterize the quality of groundwater resources in the primary aquifers of the FG study unit, not the treated drinking water delivered to consumers by water purveyors.

  7. Occurrence and distribution of dissolved pesticides in the San Joaquin River basin, California

    Science.gov (United States)

    Panshin, Sandra Yvonne; Dubrovsky, Neil M.; Gronberg, JoAnn M.; Domagalski, Joseph L.

    1998-01-01

    The effects of pesticide application, hydrology, and chemical and physical properties on the occurrence of pesticides in surface water in the San Joaquin River Basin, California, were examined. The study of pesticide occurrence in the highly agricultural San Joaquin?Tulare Basins is part of the National Water-Quality Assessment Program of the U.S. Geological Survey. One hundred forty-three water samples were collected throughout 1993 from sites on the San Joaquin River and three of its tributaries: Orestimba Creek, Salt Slough, and the Merced River. Of the 83 pesticides selected for analysis in this study, 49 different compounds were detected in samples from the four sites and ranged in concentration from less than the detection limit to 20 micrograms per liter. All but one sample contained at least one pesticide, and more than 50 percent of the samples contained seven or more pesticides. Six compounds were detected in more than 50 percent of the samples: four herbicides (dacthal, EPTC, metolachlor, and simazine) and two insecticides (chlorpyrifos and diazinon). None of the measured concentrations exceeded U.S. Environmental Protection Agency drinking water criteria, and many of the measured concentrations were very low. The concentrations of seven pesticides exceeded criteria for the protection of freshwater aquatic life: azinphos-methyl, carbaryl, chlorpyrifos, diazinon, diuron, malathion, and trifluralin. Overall, some criteria for protection of aquatic life were exceeded in a total of 97 samples. Factors affecting the spatial patterns of occurrence of the pesticides in the different subbasins included the pattern of application and hydrology. Seventy percent of pesticides with known application were detected. Overall, 40 different pesticides were detected in Orestimba Creek, 33 in Salt Slough, and 26 in the Merced River. Samples from the Merced River had a relatively low number of detections, despite the high number (35) of pesticides applied, owing to the

  8. Mechanical Analysis of Fault Interaction in the Puente Hills Region, Los Angeles Basin, California

    Science.gov (United States)

    Griffith, W. A.; Cooke, M.

    2002-12-01

    A three-dimensional model of the Puente Hills thrust system (PHT) and the Whittier fault has been constructed using published cross sections, surface trace maps [Shaw (1999); Shaw and Suppe (1996); Wright (1991)] and products of the Southern California Earthquake Center. This study utilizes boundary element method models to validate the proposed fault geometry of the Puente Hills region via investigating fault interaction. The interaction between PHT and Whittier faults is evaluated within an elastic half-space under horizontal contraction and evidenced by slip rates on faults, strain energy density (SED), and Navier-Coulomb stress (NC) throughout the host rock. Modeled slip rates are compared to paleoseismic estimates to validate the proposed fault configuration while maps of SED and NC highlight regions of high strain in the host rock and likely faulting. Subsequently, the sensitivity of SED and NC distribution to changes in fault geometry illuminate the nature of fault interaction within this complex system of interacting faults. We explore interaction of faults within the PHT region using two sets of models. The first examines slip rates and SED and NC distribution within a local model of the PHT region while the second set incorporates the PHT faults within the context of the Los Angeles basin. Both sets explore the response of the fault system to systematic addition of faults. Adding faults within regions of high SED and NC does not influence slip on neighboring faults; however the addition of fault surfaces in regions of low/moderate SED and NC reduces slip along adjacent faults. The sensitivity of fault slip rates to direction of remote contraction in the Los Angeles Basin is examined with contraction directions of 036, 017, and 006.5 [Bawden (2001), Argus (1999), and Feigl (1993)]. Furthermore, variations on intersection geometry between the PHT and Whittier fault are explored. Portions of the PHT and Whittier faults show reasonable match to available

  9. The flux and recovery of bioactive substances in the surface sediments of deep basins off southern California

    International Nuclear Information System (INIS)

    Jahnke, R.A.

    1990-01-01

    Sediment microbial community biomass and activity in Santa Monica Basin, a nearshore basin in the California Continental Borderland, were examined in October 1985, 1986 and 1987, May 1986, April 1987 and January 1990. Millimeter-scale ATP profiles and incubation of intact cores with 3 H-adenine indicated a high-biomass interface microbial population in the low-oxygen central basin, which was absent in samples from the basin slope sediments. A majority of microbial activity and organic matter mineralization occurred in the top cm of sediment. Comparison of measured ATP and total organic carbon profiles suggest that the C:ATP ratio (wt:wt) ranges between 47:1 and 77:1 in central basin interfacial populations, substantially lower than reported for other aquatic environments. Carbon production estimated from DNA synthesis measurements via 3 H-adenine incorporation was compared with TCO 2 fluxes measured by in situ benthic chamber experiments. Within the uncertainty of the C:ATP ratio, an overall microbial carbon assimilation efficiency of 75--90% was indicated. The low C:ATP ratios and high carbon assimilation efficiencies significantly affect estimates of microbial growth and respiration and are substantially different than those often assumed in the literature. These results suggest that without independent knowledge of these ratios, the uncertainty in tracer-derived microbial growth and respiration rates may be larger than previously reported. 66 refs., 8 figs., 3 tabs

  10. The flux and recovery of bioactive substances in the surface sediments of deep basins off southern California

    Energy Technology Data Exchange (ETDEWEB)

    Jahnke, R.A.

    1990-06-11

    Sediment microbial community biomass and activity in Santa Monica Basin, a nearshore basin in the California Continental Borderland, were examined in October 1985, 1986 and 1987, May 1986, April 1987 and January 1990. Millimeter-scale ATP profiles and incubation of intact cores with {sup 3}H-adenine indicated a high-biomass interface microbial population in the low-oxygen central basin, which was absent in samples from the basin slope sediments. A majority of microbial activity and organic matter mineralization occurred in the top cm of sediment. Comparison of measured ATP and total organic carbon profiles suggest that the C:ATP ratio (wt:wt) ranges between 47:1 and 77:1 in central basin interfacial populations, substantially lower than reported for other aquatic environments. Carbon production estimated from DNA synthesis measurements via {sup 3}H-adenine incorporation was compared with TCO{sub 2} fluxes measured by in situ benthic chamber experiments. Within the uncertainty of the C:ATP ratio, an overall microbial carbon assimilation efficiency of 75--90% was indicated. The low C:ATP ratios and high carbon assimilation efficiencies significantly affect estimates of microbial growth and respiration and are substantially different than those often assumed in the literature. These results suggest that without independent knowledge of these ratios, the uncertainty in tracer-derived microbial growth and respiration rates may be larger than previously reported. 66 refs., 8 figs., 3 tabs.

  11. A reassessment of the Archean-Mesoproterozoic tectonic development of the southeastern Chhattisgarh Basin, Central India through detailed aeromagnetic analysis

    Science.gov (United States)

    Sridhar, M.; Ramesh Babu, V.; Markandeyulu, A.; Raju, B. V. S. N.; Chaturvedi, A. K.; Roy, M. K.

    2017-08-01

    We constrained the geological framework over polydeformed Paleoproterozoic Sonakhan Greenstone Belt and addressed the tectonic evolution of Singhora basin in the fringes of Bastar Craton, central India by utilizing aeromagnetic data interpretation, 2.5D forward modelling and 3D magnetic susceptibility inversions. The Sonakhan Greenstone Belt exposes volcano-sedimentary sequences of the Sonakhan Group within NNW-SSE to NW-SE trending linear belts surrounded by granite gneisses, which are unconformably overlain by sedimentary rocks of Chhattisgarh Basin. The orientations of aeromagnetic anomalies are coincident with geological trends and appear to correlate with lithology and geologic structure. Regional magnetic anomalies and lineaments reveal both NNW-SSE and NE-SW trends. Prominent E-W trending linear, high amplitude magnetic anomalies are interpreted as the Trans-Chhattisgarh Aeromagnetic Lineament (TCAL). NW-SE trending aeromagnetic signatures related to Sonakhan Greenstone Belt extends below the Singhora sedimentary rocks and forms the basement in the west. The analysis suggests that TCAL is a block fault with northern block down-thrown and affected the basement rocks comprising the Sonakhan Greenstone Belt and Samblapur Granitoids. The episode of faulting represented by the TCAL is pre-Singhora sedimentation and played a vital role in basin evolution. The basement configuration image generated by estimates of depth to magnetic basement suggests a complex pattern of NNE-SSW to NE-SW trending depressions separated by a linear N-S trending basement ridge. It is inferred from the 3D magnetic susceptibility inversion that the thickness of sediments is more towards the eastern basin margin and the N-S ridge is a manifestation of post sedimentary faulting. Results of 2.5D modelling of a WNW-ESE profile across the Singhora Basin combined with results from 3D inversion suggest suggests the basin subsidence was controlled by NE-SW trending regional faults in an active

  12. Fish communities of the Sacramento River Basin: Implications for conservation of native fishes in the Central Valley, California

    Science.gov (United States)

    May, J.T.; Brown, L.R.

    2002-01-01

    The associations of resident fish communities with environmental variables and stream condition were evaluated at representative sites within the Sacramento River Basin, California between 1996 and 1998 using multivariate ordination techniques and by calculating six fish community metrics. In addition, the results of the current study were compared with recent studies in the San Joaquin River drainage to provide a wider perspective of the condition of resident fish communities in the Central Valley of California as a whole. Within the Sacramento drainage, species distributions were correlated with elevational and substrate size gradients; however, the elevation of a sampling site was correlated with a suite of water-quality and habitat variables that are indicative of land use effects on physiochemical stream parameters. Four fish community metrics - percentage of native fish, percentage of intolerant fish, number of tolerant species, and percentage of fish with external anomalies - were responsive to environmental quality. Comparisons between the current study and recent studies in the San Joaquin River drainage suggested that differences in water-management practices may have significant effects on native species fish community structure. Additionally, the results of the current study suggest that index of biotic integrity-type indices can be developed for the Sacramento River Basin and possibly the entire Central Valley, California. The protection of native fish communities in the Central Valley and other arid environments continues to be a conflict between human needs for water resources and the requirements of aquatic ecosystems; preservation of these ecosystems will require innovative management strategies.

  13. Hydrocarbon emissions from twelve urban shade trees of the Los Angeles, California, Air Basin

    Science.gov (United States)

    Corchnoy, Stephanie B.; Arey, Janet; Atkinson, Roger

    The large-scale planting of shade trees in urban areas to counteract heat-island effects and to minimize energy use is currently being discussed. Among the costs to be considered in a cost/benefit analysis of such a program is the potential for additional reactive organic compounds in the atmosphere due to emissions from these trees. In this program, 15 species of potential shade trees for the Los Angeles Air Basin were studied and emission rates were determined for 11 of these trees, with one further tree (Crape myrtle) exhibiting no detectable emissions. The emission rates normalized to dry leaf weight and corrected to 30°C were (in μg g -1 h -1), ranked from lowest to highest emission rate: Crape myrtle, none detected; Camphor, 0.03; Aleppo pine, 0.15; Deodar cedar, 0.29; Italian Stone pine, 0.42; Monterey pine, 0.90; Brazilian pepper, 1.3; Canary Island pine, 1.7; Ginkgo, 3.0; California pepper, 3.7; Liquidambar, 37; Carrotwood, 49. In addition to the emission rates per unit biomass, the biomass per tree must be factored into any assessment of the relative merits of the various trees, since some trees have higher biomass constants than others. The present data shows that there are large differences in emission rates among different tree species and this should be factored into decision-making as to which shade trees to plant. Based solely on the presently determined emission rates, the Crape myrtle and Camphor tree are good choices for large-scale planting, while the Carrotwood tree and Liquidambar are poor choices due to their high isoprene emission rates.

  14. Simulation-optimization aids in resolving water conflict: Temecula Basin, Southern California

    Science.gov (United States)

    Hanson, Randall T.; Faunt, Claudia C.; Schmid, Wolfgang; Lear, Jonathan

    2014-01-01

    The productive agricultural areas of Pajaro Valley, California have exclusively relied on ground water from coastal aquifers in central Monterey Bay. As part of the Basin Management Plan (BMP), the Pajaro Valley Water Management Agency (PVWMA) is developing additional local supplies to replace coastal pumpage, which is causing seawater intrusion. The BMP includes an aquifer storage and recovery (ASR) system, which captures and stores local winter runoff, and supplies it to growers later in the growing season in lieu of ground-water pumpage. A Coastal Distribution System (CDS) distributes water from the ASR and other supplemental sources. A detailed model of the Pajaro Valley is being used to simulate the coupled supply and demand components of irrigated agriculture from 1963 to 2006. Recent upgrades to the Farm Process in MODFLOW (MF2K-FMP) allow simulating the effects of ASR deliveries and reduced pumping for farms in subregions connected to the CDS. The BMP includes a hierarchy of monthly supply alternatives, including a recovery well field around the ASR system, a supplemental wellfield, and onsite farm supply wells. The hierarchy of delivery requirements is used by MF2K-FMP to estimate the effects of these deliveries on coastal ground-water pumpage and recovery of water levels. This integrated approach can be used to assess the effectiveness of the BMP under variable climatic conditions, and to test the impacts of more complete subscription by coastal farmers to the CDS deliveries. The model will help managers assess the effects of new BMP components to further reduce pumpage and seawater intrusion.

  15. Volcanic and Tectonic Evolution of The Gulf of California Near Mulege, Baja California Sur: Results From Baja Basins NSF-REU (Research Experience for Undergraduates)

    Science.gov (United States)

    Hutchinson, S. J.; Allard, J.; Acuna, N.; Graettinger, A. H.; Busby, C.

    2017-12-01

    Cenozoic volcanic rocks have been studied along many parts of the Gulf of California margin of Baja California because they provide a record of its volcano-tectonic evolution, from subduction (24-12 Ma), to rifting (820 m thick red bed sequence, sourced to the east by andesitic volcanic rocks eroded from the footwall of a west-dipping normal fault. Proximal alluvial fan bajada deposits are debris-flow dominated, with angular clasts up to 1.3 m in size. Distal braided stream deposits have sandstones and cobble conglomerates, with abundant cut and fill structures and rounded clasts. Adakite trachyandesite block-and-ash-flow tuffs are interstratified with the proximal deposits, representing pyroclastic flows generated by collapse of lava domes plumbed up the basin-bounding fault to the east. (2) The redbeds were cut by a dike swarm that fed a field of lava shield volcanoes. The dikes and lava shields include calcalkaline basaltic andesite, andesite and dacite, as well as magnesian trachyandesite and basaltic andesite. (3) A N-S, subvertical fault stepped into the basin and dropped the lava shields down to the east, while they were eroded off the uplifted footwall to the west. (4) The footwall block was beveled and overlain by plateau-forming magnesian basaltic trachyandesite lavas. Basal clastic sequences in the Baja Gulf of California margin have been inferred to represent Oligocene forearc rocks, with overlying volcanic rocks recording westward sweep of the Miocene arc into the area. However, on the basis of our geochemistry, we infer that all of these rocks record post-subduction (<12 Ma) processes. 1 Acuna et al., this volume

  16. Middle-late Holocene climate variability in La Paz Basin, southern Gulf of California

    Science.gov (United States)

    Gómez-Lizárraga, L. E.; Perez-Cruz, L. L.; Fucugauchi, J. U.

    2013-12-01

    Sediments from DIPAL III-K47 core collected at 830 m depth in the western slope within the oxygen minimum zone of La Paz Basin, southern Gulf of California provide a detailed record of paleoceanography and paleoclimatology for the tropical Pacific on centennial time scales for the past 7300 years. The sedimentary sequence is compose of hemipelagic sediments and is laminated throughout its entire length (145 cm). According to the preliminary age model based on radiocarbon AMS dates, core covers the period from ca 7300 to 1000 cal yr BP. The estimated sedimentation rates are between 0.20 and 0.29 mm/yr. Radiolarian assemblages, geochemical (major and trace elements Al, Ba, Ca, K, Si Ti, Zr and Zr/Al and Ba/Al ratios) and magnetic susceptibility are used as proxies of variations of oceanic circulation patterns, paleoproductivity, aeolian activity and precipitation. Eighty-two intervals were sampled for radiolarians and the core was sampled at 1-cm intervals to produce records of major and trace elements. Factor Analysis of the radiolarian abundances counted in sediments samples identified three assemblages. The first one (Arachnocorallium calvata, Lithomelissa setosa, Lithomelissa thoracites and Peridium longispinum) suggests winter-spring like conditions (cold and dry), Gulf of California Water persistence and a relative increase in productivity that might become from the east-to-west upwelling gradient. The second radiolarian assemblage (Tetrapyle octacantha group and Phorticium pylonium group) was interpreted as stratification of the column water and the incursion of warm, oligotrophic Tropical Surface Water that remind summer-fall like conditions. The third assemblage (Clathrocircus stapedius, Phorticium pylonium group, Lithomelissa pentacantha, Phormacantha hystrix, Phormospyris stabilis scaphipes, Lithomelissa thoracites, Pseudocubus obeliscus, Druppatractus irregularis and Druppatractus variabilis), suggests a mix water column that favors the organic carbon

  17. Surface water of Little River basin in southeastern Oklahoma (with a section on quality of water by R. P. Orth)

    Science.gov (United States)

    Westfall, A.O.; Orth, Richard Philip

    1963-01-01

    This report summarizes basic hydrologic data of the surface water resources of Little River basin above the Oklahoma-Arkansas state line near Cerrogordo, Okla., and by analysis and interpretation, presents certain streamflow characteristics at specified points in the basin. Little River basin above the state line includes 2,269 square miles, of which about 250 square miles of the Mountain Fork River is in Arkansas. The climate is humid and the annual precipitation averages about 46 inches. Gross annual lake evaporation averages 49 inches per year. There are three reservoirs totaling 2,831,800 acre-feet of storage, either authorized or under construction in the basin. The average annual discharge at the gaging stations for the period 1930-61 is 674,900 acre-feet for Little River near Wright City; 1,273,000 acre-feet for Little River below Lukfata Creek, near Idabel; and 989,000 acre-feet for Mountain Fork River near Eagletown. The average annual discharge of Little River at the Oklahoma-Arkansas state line near Cerrogordo is 2,401,000 acre-feet. Flow-duration curves have been developed from daily records for the gaging stations. These curves show the percentage of time various rates of discharge have been equaled or exceeded. Procedures for defining the frequency of annual floods at any point in the basin are given. Low-flow frequency curves for the gaging stations defining the recurrence intervals of 7, 14 or 15, 30, 60, and 120 day mean flows have been prepared. Curves showing the relation of instantaneous discharge at specified upstream points to the daily mean discharge at two gaging stations are presented. The storage requirements for suplementing natural flows have been prepared for the gaging-station sites. Chemical analyses show that the surface water in the basin is suitable for domestic and industrial uses.

  18. Simulation of Ground-Water Flow in the Irwin Basin Aquifer System, Fort Irwin National Training Center, California

    Science.gov (United States)

    Densmore, Jill N.

    2003-01-01

    Ground-water pumping in the Irwin Basin at Fort Irwin National Training Center, California resulted in water-level declines of about 30 feet from 1941 to 1996. Since 1992, artificial recharge from wastewater-effluent infiltration and irrigation-return flow has stabilized water levels, but there is concern that future water demands associated with expansion of the base may cause a resumption of water-level declines. To address these concerns, a ground-water flow model of the Irwin Basin was developed to help better understand the aquifer system, assess the long-term availability and quality of ground water, and evaluate ground-water conditions owing to current pumping and to plan for future water needs at the base. Historical data show that ground-water-level declines in the Irwin Basin between 1941 and 1996, caused the formation of a pumping depression near the pumped wells, and that recharge from the wastewater-treatment facility and disposal area caused the formation of a recharge mound. There have been two periods of water-level recovery in the Irwin Basin since the development of ground water in this basin; these periods coincide with a period of decreased pumpage from the basin and a period of increased recharge of water imported from the Bicycle Basin beginning in 1967 and from the Langford Basin beginning in 1992. Since 1992, artificial recharge has exceeded pumpage in the Irwin Basin and has stabilized water-level declines. A two-layer ground-water flow model was developed to help better understand the aquifer system, assess the long-term availability and quality of ground water, and evaluate ground-water conditions owing to current pumping and to plan for future water needs at the base. Boundary conditions, hydraulic conductivity, altitude of the bottom of the layers, vertical conductance, storage coefficient, recharge, and discharge were determined using existing geohydrologic data. Rates and distribution of recharge and discharge were determined from

  19. Preliminary hydrogeologic assessment near the boundary of the Antelope Valley and El Mirage Valley groundwater basins, California

    Science.gov (United States)

    Stamos, Christina L.; Christensen, Allen H.; Langenheim, Victoria

    2017-07-19

    The increasing demands on groundwater for water supply in desert areas in California and the western United States have resulted in the need to better understand groundwater sources, availability, and sustainability. This is true for a 650-square-mile area that encompasses the Antelope Valley, El Mirage Valley, and Upper Mojave River Valley groundwater basins, about 50 miles northeast of Los Angeles, California, in the western part of the Mojave Desert. These basins have been adjudicated to ensure that groundwater rights are allocated according to legal judgments. In an effort to assess if the boundary between the Antelope Valley and El Mirage Valley groundwater basins could be better defined, the U.S. Geological Survey began a cooperative study in 2014 with the Mojave Water Agency to better understand the hydrogeology in the area and investigate potential controls on groundwater flow and availability, including basement topography.Recharge is sporadic and primarily from small ephemeral washes and streams that originate in the San Gabriel Mountains to the south; estimates range from about 400 to 1,940 acre-feet per year. Lateral underflow from adjacent basins has been considered minor in previous studies; underflow from the Antelope Valley to the El Mirage Valley groundwater basin has been estimated to be between 100 and 1,900 acre-feet per year. Groundwater discharge is primarily from pumping, mostly by municipal supply wells. Between October 2013 and September 2014, the municipal pumpage in the Antelope Valley and El Mirage Valley groundwater basins was reported to be about 800 and 2,080 acre-feet, respectively.This study was motivated by the results from a previously completed regional gravity study, which suggested a northeast-trending subsurface basement ridge and saddle approximately 3.5 miles west of the boundary between the Antelope Valley and El Mirage Valley groundwater basins that might influence groundwater flow. To better define potential basement

  20. A late Pleistocene tephra layer in the southern Great Basin and Colorado Plateau derived from Mono Craters, California

    Science.gov (United States)

    Madsen, D.B.; Sarna-Wojcicki, A. M.; Thompson, R.S.

    2002-01-01

    A newly identified tephra in stratified deposits in southwestern Utah, dated ???14,000 14C yr B.P., may aid in correlating late Pleistocene deposits across parts of the southern Great Basin and west-central Colorado Plateau. Geochemical analyses of the ash suggest the tephra originated from Mono Craters, California, and most probably correlates with Wilson Creek ash #3. Because the ash is 2 mm thick ???550 km from its source, the event may have been larger than others correlated to Mono Craters eruptions. ?? 2002 University of Washington.

  1. Land use change and effects on water quality and ecosystem health in the Lake Tahoe basin, Nevada and California

    Science.gov (United States)

    Forney, William; Richards, Lora; Adams, Kenneth D.; Minor, Timothy B.; Rowe, Timothy G.; Smith, J. LaRue; Raumann, Christian G.

    2001-01-01

    Human activity in the Lake Tahoe Basin has increased substantially in the past four decades, causing significant impacts on the quality and clarity of the lake's famous deep, clear water. Protection of Lake Tahoe and the surrounding environment has become an important activity in recent years. A variety of agencies, including the Tahoe Regional Planning Agency, Tahoe Research Group of the University of California at Davis, Desert Research Institute of the University and Community College System of Nevada, U.S. Geological Survey (USGS), and a host of State (both Nevada and California) and local agencies have been monitoring and conducting research in the Basin in order to understand how the lake functions and to what extent humans have affected its landscape and ecosystem processes. In spite of all of these activities, there remains a lack of comprehensive land use change data and analysis for the Basin. A project is underway that unites the land cover mapping expertise of the USGS National Mapping Discipline with the hydrologic expertise of the Water Resources Discipline to assess the impacts of urban growth and land use change in the Lake Tahoe Basin. Three activities are planned over the next 3 years: (1) mapping the current and historic state of the land surface, (2) conducting analysis to document patterns, rates, and trends in urbanization, land use change, and ecosystem health, and (3) assessing the causes and consequences of land use change with regard to water quality and ecosystem health. We hypothesize that changes in the extent of urban growth and the corresponding increases in impervious surfaces and decreases in natural vegetation have resulted in severe impacts on ecosystem health and integrity, riparian zones and water quality over time. We are acting on multiple fronts to test this hypothesis through the quantification of landscape disturbances and impacts.

  2. High resolution paleoceanography of the Guaymas Basin, Gulf of California, during the past 15 000 years

    Science.gov (United States)

    Barron, J.A.; Bukry, D.; Bischoff, J.L.

    2004-01-01

    Deep Sea Drilling Project Site 480 (27??54.10???N, 111??39.34???W; 655 m water depth) contains a high resolution record of paleoceanographic change of the past 15 000 years for the Guaymas Basin, a region of very high diatom productivity within the central Gulf of California. Analyses of diatoms and silicoflagellates were completed on samples spaced every 40-50 yr, whereas ICP-AES geochemical analyses were completed on alternate samples (sample spacing 80-100 yr). The B??lling-Aller??d interval (14.6-12.9 ka) (note, ka refers to 1000 calendar years BP throughout this report) is characterized by an increase in biogenic silica and a decline in calcium carbonate relative to surrounding intervals, suggesting conditions somewhat similar to those of today. The Younger Dryas event (12.9-11.6 ka) is marked by a major drop in biogenic silica and an increase in calcium carbonate. Increasing relative percentage contributions of Azpeitia nodulifera and Dictyocha perlaevis (a tropical diatom and silicoflagellate, respectively) and reduced numbers of the silicoflagellate Octactis pulchra are supportive of reduced upwelling of nutrient-rich waters. Between 10.6 and 10.0 ka, calcium carbonate and A. nodulifera abruptly decline at DSDP 480, while Roperia tesselata, a diatom indicative of winter upwelling in the modern-day Gulf, increases sharply in numbers. A nearly coincident increase in the silicoflagellate Dictyocha stapedia suggests that waters above DSDP 480 were more similar to the cooler and slightly more saline waters of the northern Gulf during much of the early and middle parts of the Holocene (???10 to 3.2 ka). At about 6.2 ka a stepwise increase in biogenic silica and the reappearance of the tropical diatom A. nodulifera marks a major change in oceanographic conditions in the Gulf. A winter shift to more northwesterly winds may have occurred at this time along with the onset of periodic northward excursions (El Nin??o-driven?) of the North Equatorial Countercurrent

  3. Mercury and Methylmercury concentrations and loads in Cache Creek Basin, California, January 2000 through May 2001

    Science.gov (United States)

    Domagalski, Joseph L.; Alpers, Charles N.; Slotton, Darrell G.; Suchanek, Thomas H.; Ayers, Shaun M.

    2004-01-01

    Concentrations and mass loads of total mercury and methylmercury in streams draining abandoned mercury mines and near geothermal discharge in Cache Creek Basin, California, were measured during a 17-month period from January 2000 through May 2001. Rainfall and runoff averages during the study period were lower than long-term averages. Mass loads of mercury and methylmercury from upstream sources to downstream receiving waters, such as San Francisco Bay, were generally the highest during or after winter rainfall events. During the study period, mass loads of mercury and methylmercury from geothermal sources tended to be greater than those from abandoned mining areas because of a lack of large precipitation events capable of mobilizing significant amounts of either mercury-laden sediment or dissolved mercury and methylmercury from mine waste. Streambed sediments of Cache Creek are a source of mercury and methylmercury to downstream receiving bodies of water such as the Delta of the San Joaquin and Sacramento Rivers. Much of the mercury in these sediments was deposited over the last 150 years by erosion and stream discharge from abandoned mines or by continuous discharges from geothermal areas. Several geochemical constituents were useful as natural tracers for mining and geothermal areas. These constituents included aqueous concentrations of boron, chloride, lithium, and sulfate, and the stable isotopes of hydrogen and oxygen in water. Stable isotopes of water in areas draining geothermal discharges were enriched with more oxygen-18 relative to oxygen-16 than meteoric waters, whereas the enrichment by stable isotopes of water from much of the runoff from abandoned mines was similar to that of meteoric water. Geochemical signatures from stable isotopes and trace-element concentrations may be useful as tracers of total mercury or methylmercury from specific locations; however, mercury and methylmercury are not conservatively transported. A distinct mixing trend of

  4. Age, distribution, and stratigraphic relationship of rock units in the San Joaquin Basin Province, California: Chapter 5 in Petroleum systems and geologic assessment of oil and gas in the San Joaquin Basin Province, California

    Science.gov (United States)

    Hosford Scheirer, Allegra; Magoon, Leslie B.

    2008-01-01

    The San Joaquin Basin is a major petroleum province that forms the southern half of California’s Great Valley, a 700-km-long, asymmetrical basin that originated between a subduction zone to the west and the Sierra Nevada to the east. Sedimentary fill and tectonic structures of the San Joaquin Basin record the Mesozoic through Cenozoic geologic history of North America’s western margin. More than 25,000 feet (>7,500 meters) of sedimentary rocks overlie the basement surface and provide a nearly continuous record of sedimentation over the past ~100 m.y. Further, depositional geometries and fault structures document the tectonic evolution of the region from forearc setting to strike-slip basin to transpressional margin. Sedimentary architecture in the San Joaquin Basin is complicated because of these tectonic regimes and because of lateral changes in depositional environment and temporal changes in relative sea level. Few formations are widespread across the basin. Consequently, a careful analysis of sedimentary facies is required to unravel the basin’s depositional history on a regional scale. At least three high-quality organic source rocks formed in the San Joaquin Basin during periods of sea level transgression and anoxia. Generated on the basin’s west side, hydrocarbons migrated into nearly every facies type in the basin, from shelf and submarine fan sands to diatomite and shale to nonmarine coarse-grained rocks to schist. In 2003, the U.S. Geological Survey (USGS) completed a geologic assessment of undiscovered oil and gas resources and future additions to reserves in the San Joaquin Valley of California (USGS San Joaquin Basin Province Assessment Team, this volume, chapter 1). Several research aims supported this assessment: identifying and mapping the petroleum systems, modeling the generation, migration, and accumulation of hydrocarbons, and defining the volumes of rock to be analyzed for additional resources. To better understand the three dimensional

  5. Competition between agricultural, urban, and sand-mining areas at the Paraíba do Sul basin in southeastern Brazil

    Science.gov (United States)

    Ronquim, Carlos C.; Cordeiro, Guilherme P. L.; Amorim, Mariana de; de C. Teixeira, Antônio H.; Leivas, Janice F.; Galdino, Sergio

    2017-10-01

    This work was performed in the Paraíba do Sul basin, within the limits of the São Paulo state, southeastern Brazil, in order to assess the dynamics of the land-use and land-cover changes at the Paraíba do Sul river's floodplains between 1985 and 2016. We focused on investigating the development of agricultural areas used for the production of wetland rice and of areas featuring artificial lakes produced by sand mining. We mapped the land cover in 1985 using images made by the Landsat 5 satellite's Moderate Resolution Imaging Spectroradiometer (MODIS) and Thematic Mapper (TM) sensors, which were segmented to produce vectors featuring homogeneous characteristics, and which were classified by means of visual interpretation. Similarly, we applied the maximum likelihood classification and used spectral curve inserts and adjustments to study and analyze the same area using a Landsat 8's Operational Land Imager (OLI) image made in 2016. Our results show significant reduction of areas used for rice crops, and increase in areas featuring sandmining pits. The rice crop areas decreased approximately 43% from 24,131.4 ha in 1985 to 13,789.8 ha in 2016. Over this 30-year period, the area covered by sand-mining lakes increased from 615 ha to 3,876 ha (+ 630%), and the number of lakes increased from 54 to 316. Sand mining and urbanization are the main factors causing the reduction in wetland rice areas. The absence of environmental management actions at the basin interferes with the rice production, which depends on the Paraíba do Sul river's floodplains.

  6. Impact of change in erosion rate and landscape steepness on hillslope and fluvial sediments grain size in the Feather River basin (Sierra Nevada, California)

    OpenAIRE

    M. Attal; S. M. Mudd; M. D. Hurst; B. Weinman; K. Yoo; M. Naylor

    2015-01-01

    The characteristics of the sediment transported by rivers (e.g. sediment flux, grain size distribution – GSD) dictate whether rivers aggrade or erode their substrate. They also condition the architecture and properties of sedimentary successions in basins. In this study, we investigate the relationship between landscape steepness and the grain size of hillslope and fluvial sediments. The study area is located within the Feather River basin in northern California, and studied...

  7. Planning and design of studies for river-quality assessment in the Truckee and Carson River basins, California and Nevada

    Science.gov (United States)

    Nowlin, Jon O.; Brown, W.M.; Smith, L.H.; Hoffman, R.J.

    1980-01-01

    The objectives of the Geological Survey 's river-quality assessment in the Truckee and Carson River basins in California and Nevada are to identify the significant resource management problems; to develop techniques to assess the problems; and to effectively communicate results to responsible managers. Six major elements of the assessment to be completed by October 1981 are (1) a detailing of the legal, institutional, and structural development of water resources in the basins and the current problems and conflicts; (2) a compilation and synthesis of the physical hydrology of the basins; (3) development of a special workshop approach to involve local management in the direction and results of the study; (4) development of a comprehensive streamflow model emcompassing both basins to provide a quantitative hydrologic framework for water-quality analysis; (5) development of a water-quality transport model for selected constituents and characteristics on selected reaches of the Truckee River; and (6) a detailed examination of selected fish habitats for specified reaches of the Truckee River. Progress will be periodically reported in reports, maps, computer data files, mathematical models, a bibliography, and public presentations. In building a basic framework to develop techniques, the basins were viewed as a single hydrologic unit because of interconnecting diversion structures. The framework comprises 13 hydrographic subunits to facilitate modeling and sampling. Several significant issues beyond the scope of the assessment were considered as supplementary proposals; water-quality loadings in Truckee and Carson Rivers, urban runoff in Reno and management alternatives, and a model of limnological processes in Lahontan Reservoir. (USGS)

  8. Conodont and fusulinid biostratigraphy and history of the Pennsylvanian to Lower Permian Keeler Basin, east-central California

    Science.gov (United States)

    Stevens, C.H.; Stone, P.; Ritter, S.M.

    2001-01-01

    The Pennsylvanian-Lower Permian Keeler Canyon Formation and lower part of the Lower Permian Lone Pine Formation in east-central California were deposited in a deep-water basin that originated in the Morrowan (Early Pennsylvanian), was fully established by the Desmoinesian (Middle Pennsylvanian), and lasted into the Sakmarian (Early Permian). Stratigraphic studies indicate that the Keeler Canyon Formation can be divided into members recognizable throughout the area of our detailed mapping. From older to younger they are the Tinemaha Reservoir, Tihvipah Limestone, Cerro Gordo Spring, and Salt Tram Members. Rocks in this basin, here referred to as the Keeler basin, contain numerous fusulinid and conodont faunas most of which were deposited by sediment-gravity flows probably originating at the margin of the Bird Spring carbonate platform to the northeast. Sixty-one species of Atokan to Sakmarian fusulinids and 38 species of Desmoinesian to Sakmarian conodonts are recognized. These, in addition to four species of Morrowan conodonts previously reported, show that every stage from the Morrowan to Sakmarian is represented in the basin. The fusulinid faunas are composed largely of taxa of the North American craton, especially the south-central USA, with important endemic constituents and some McCloud Limestone forms, representing the Eastern Klamath terrane. Conodonts are closely similar to species in the Ural Mountains region of Russia and Kazakhstan, as well as the American midcontinent. The co-occurrence of fusulinids and conodonts in the Keeler basin results in a better correlation of zones based on these two groups of fossils than generally is possible.

  9. Ground-Water Storage Change and Land Subsidence in Tucson Basin and Avra Valley, Southeastern Arizona, 1998-2002

    Science.gov (United States)

    Pool, Donald R.; Anderson, Mark T.

    2008-01-01

    Gravity and land subsidence were measured annually at wells and benchmarks within two networks in Tucson Basin and Avra Valley from 1998 to 2002. Both networks are within the Tucson Active Management Area. Annual estimates of ground-water storage change, ground-water budgets, and land subsidence were made based on the data. Additionally, estimates of specific yield were made at wells within the monitored region. Increases in gravity and water-level rises followed above-average natural recharge during winter 1998 in Tucson Basin. Overall declining gravity and water-level trends from 1999 to 2002 in Tucson Basin reflected general declining ground-water storage conditions and redistribution of the recent recharge throughout a larger region of the aquifer. The volume of stored ground-water in the monitored portion of Tucson Basin increased 200,000 acre-feet from December 1997 to February 1999; however, thereafter an imbalance in ground-water pumpage in excess of recharge led to a net storage loss for the monitoring period by February 2002. Ground-water storage in Avra Valley increased 70,000 acre-feet during the monitoring period, largely as a result of artificial and incidental recharge in the monitored region. The water-budget for the combined monitored regions of Tucson Basin and Avra Valley was dominated by about 460,000 acre-feet of recharge during 1998 followed by an average-annual recharge rate of about 80,000 acre-feet per year from 1999 to 2002. Above-average recharge during winter 1998, followed by average-annual deficit conditions, resulted in an overall balanced water budget for the monitored period. Monitored variations in storage compared well with simulated average-annual conditions, except for above-average recharge from 1998 to 1999. The difference in observed and simulated conditions indicate that ground-water flow models can be improved by including climate-related variations in recharge rates rather than invariable rates of average-annual recharge

  10. Stomach contents of the Pacific sharpnose shark, Rhizoprionodon longurio (Carcharhiniformes, Carcharhinidae in the southeastern Gulf of California

    Directory of Open Access Journals (Sweden)

    Yolene R Osuna-Peralta

    2014-07-01

    Full Text Available The feeding habits of the sharpnose shark Rhizoprionodon longurio of the SE Gulf of California are described using the stomach contents of 250 specimens (135 males and 115 females obtained weekly from December 2007 to March 2008 in the two main landing sites of the artisanal fishing fleet of Mazatlan. The mean total length (TL was 77.7 ± 12.8 cm and the respective ranges for males and females were 60-120 cm and 52120 cm. Size distribution showed two modal groups (juveniles: 52-80 cm, mode 72.5 cm, and adults: 85-140 cm, mode 92.5 cm. Out of the 395 preys identified in 235 stomachs with identifiable contents, the most important were cephalopods (Index of Relative Importance, IRI = 93.1%, mainly Argonauta spp. (IRI = 92.9%. The total IRI value for fish was 5.9%, mostly represented by Oligoplites refulgens and Oligoplites sp. (joint IRI value = 4.8%. The diversity of the stomach contents of males and females was not significantly different, and although the values of diversity, equitability and dietary breadth indexes were lower in juveniles than in adults, ANOSIM analysis did not show differences in dietary habits related to age and sex. The results indicate a specialized feeding behaviour, with Argonauta spp. as preferred prey. This behaviour does not agree with all previous information on R. longurio, and is probably due to local availability of this prey during the sampling period.

  11. Crustal structure determined from ambient noise tomography near the magmatic centers of the Coso region, southeastern California

    Science.gov (United States)

    Yang, Yingjie; Ritzwoller, Michael H.; Jones, Craig H.

    2011-02-01

    We apply seismic ambient noise tomography to image and investigate the shallow shear velocity structure beneath the Coso geothermal field and surrounding areas. Data from a PASSCAL experiment operated within the Coso geothermal field between 1998 and 2000 and surrounding broadband stations from the Southern California Seismic Network are acquired and processed. Daily cross correlations of ambient noise between all pairs of stations that overlapped in time of deployment were calculated and then stacked over the duration of deployment. Phase velocities of Rayleigh waves between 3 and 10 s periods are measured from the resulting cross correlations. Depending on the period, between about 300 and 600 reliable phase velocity measurements are inverted for phase velocity maps from 3 to 10 s periods, which in turn are inverted for a 3-D shear velocity model beneath the region. The resulting 3-D model reveals features throughout the region that correlate with surface geology. Beneath the Coso geothermal area shear velocities are generally depressed, a prominent low-velocity anomaly is resolved clearly within the top 2 km, no significant anomaly is seen below about 14 km depth, and a weakly resolved anomaly is observed between 6 and 12 km depth. The anomaly in the top 2 km probably results from geothermal alteration in the shallow subsurface, no magmatic body is imaged beneath 14 km depth, but the shear velocity anomaly between 6 and 12 km may be attributable to partial melt. The thickness and amplitude of the magma body trade off in the inversion and are ill determined. Low velocities in the regions surrounding Coso at depths near 7 km underlie areas with Miocene to recent volcanism, suggesting that some magmatic processing of the crust could be focused near this depth.

  12. The geochemical record of the last 17,000 years in the Guaymas Basin, Gulf of California

    Science.gov (United States)

    Dean, W.E.

    2006-01-01

    Sediments deposited on the western slope of the Guaymas Basin in the central Gulf of California are composed predominantly of detrital clastic material and biogenic silica (biopal), with minor organic material (average of 2.8% organic carbon) and calcium carbonate. The CaCO3 is derived from calcareous plankton and is highly variable ranging from 0% to 16%. In general, the CaCO3 content of the sediments varies inversely with the biopal content, reflecting the relative abundance of calcareous and siliceous plankton in the photic zone. Siliceous plankton dominate when winds are predominantly out of the northwest producing strong upwelling. Calcareous plankton indicates weak southeasterly winds that bring warm, tropical Pacific surface water into the Gulf. Based mainly on relative abundances of biopal and CaCO3, the sediments deposited over the last 17,000 years in the western Guaymas Basin can be divided into five intervals. In general, the sediments in the intervals with high biopal and low CaCO3 are laminated, but this is not always true. Unlike most other continental margins of the world with well-developed oxygen minimum zones where highest concentrations of organic carbon and redox-sensitive trace metals occur in laminated sediments, the laminated sediments on the anoxic slope of the western Guaymas Basin do not always have the highest concentrations of organic carbon and trace metals such as Mo and Cd.

  13. Biology and ecomorphology of stream fishes from the rio Mogi-Guaçu basin, Southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Katiane M. Ferreira

    Full Text Available The córrego Paulicéia is a direct tributary of the rio Mogi-Guaçu, located in Santa Rita do Passa Quatro, State of São Paulo, Southeastern Brazil. This stream runs inside a savannah-like (cerrado environment and it associated vegetation. Biological and ecomorphological aspects of its fish community were studied in three stretches of the stream, denominated herein as the upper, middle and lower courses. The fish fauna recorded in this study consisted of 15 species, belonging to five orders and nine families, based in a total of 715 collected individuals representing 1,450 kg of biomass. The most important abiotic factors related to the occurrence and distribution of the fish fauna were the substrate, current speed, and presence or absence of riparian vegetation. The analysis of 336 stomach contents of 13 species demonstrated that 65% of food items are autochthonous, 32% allochthonous, and 3% are of unknown origin. Four alimentary guilds could be identified, based on the predominant food items: omnivores with tendency to insectivory - Astyanax paranae, A. fasciatus and Piabina argentea; larvivores - Corydoras difluviatilis, Cetopsorhamdia iheringi, Phenacorhamdia tenebrosa, Characidium gomesi, Eigenmannia virescens, and Rhamdia quelen; periphyton feeders - Hisonotus sp., Hypostomus ancistroides and Synbranchus marmoratus; and piscivore - Hoplias malabaricus. Reproductions data are presented for Astyanax altiparanae and Hisontus sp. Three ecomorphological groups could be established, based on swimming, feeding, and microhabitat strategies: nektonic (A. fasciatus, A. paranae, Bryconamericus stramineus, P. argentea, H. malabaricus and Phallotorynus jucundus, benthic (C. gomesi, P. tenebrosa, C. iheringi, R. quelen, C. difluviatilis, H. ancistroides and Hisonotus sp., and necktobenthic (E. virescens and S. marmoratus.

  14. Groundwater quality in the Western San Joaquin Valley study unit, 2010: California GAMA Priority Basin Project

    Science.gov (United States)

    Fram, Miranda S.

    2017-06-09

    Water quality in groundwater resources used for public drinking-water supply in the Western San Joaquin Valley (WSJV) was investigated by the USGS in cooperation with the California State Water Resources Control Board (SWRCB) as part of its Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Project. The WSJV includes two study areas: the Delta–Mendota and Westside subbasins of the San Joaquin Valley groundwater basin. Study objectives for the WSJV study unit included two assessment types: (1) a status assessment yielding quantitative estimates of the current (2010) status of groundwater quality in the groundwater resources used for public drinking water, and (2) an evaluation of natural and anthropogenic factors that could be affecting the groundwater quality. The assessments characterized the quality of untreated groundwater, not the quality of treated drinking water delivered to consumers by water distributors.The status assessment was based on data collected from 43 wells sampled by the U.S. Geological Survey for the GAMA Priority Basin Project (USGS-GAMA) in 2010 and data compiled in the SWRCB Division of Drinking Water (SWRCB-DDW) database for 74 additional public-supply wells sampled for regulatory compliance purposes between 2007 and 2010. To provide context, concentrations of constituents measured in groundwater were compared to U.S. Environmental Protection Agency (EPA) and SWRCB-DDW regulatory and non-regulatory benchmarks for drinking-water quality. The status assessment used a spatially weighted, grid-based method to estimate the proportion of the groundwater resources used for public drinking water that has concentrations for particular constituents or class of constituents approaching or above benchmark concentrations. This method provides statistically unbiased results at the study-area scale within the WSJV study unit, and permits comparison of the two study areas to other areas assessed by the GAMA Priority Basin Project

  15. Groundwater-Quality Data in the South Coast Interior Basins Study Unit, 2008: Results from the California GAMA Program

    Science.gov (United States)

    Mathany, Timothy M.; Kulongoski, Justin T.; Ray, Mary C.; Belitz, Kenneth

    2009-01-01

    Groundwater quality in the approximately 653-square-mile South Coast Interior Basins (SCI) study unit was investigated from August to December 2008, as part of the Priority Basins Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basins Project was developed in response to Legislative mandates (Supplemental Report of the 1999 Budget Act 1999-00 Fiscal Year; and, the Groundwater-Quality Monitoring Act of 2001 [Sections 10780-10782.3 of the California Water Code, Assembly Bill 599]) to assess and monitor the quality of groundwater used as public supply for municipalities in California, and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). SCI was the 27th study unit to be sampled as part of the GAMA Priority Basins Project. This study was designed to provide a spatially unbiased assessment of the quality of untreated groundwater used for public water supplies within SCI, and to facilitate statistically consistent comparisons of groundwater quality throughout California. Samples were collected from 54 wells within the three study areas [Livermore, Gilroy, and Cuyama] of SCI in Alameda, Santa Clara, San Benito, Santa Barbara, Ventura, and Kern Counties. Thirty-five of the wells were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study unit (grid wells), and 19 were selected to aid in evaluation of specific water-quality issues (understanding wells). The groundwater samples were analyzed for organic constituents [volatile organic compounds (VOCs), pesticides and pesticide degradates, polar pesticides and metabolites, and pharmaceutical compounds], constituents of special interest [perchlorate and N-nitrosodimethylamine (NDMA)], naturally occurring inorganic constituents [trace elements, nutrients, major and minor ions, silica, total dissolved solids (TDS), and alkalinity

  16. Hydrological conditions and evaluation of sustainable groundwater use in the Sierra Vista Subwatershed, Upper San Pedro Basin, southeastern Arizona

    Science.gov (United States)

    Gungle, Bruce; Callegary, James B.; Paretti, Nicholas V.; Kennedy, Jeffrey R.; Eastoe, Christopher J.; Turner, Dale S.; Dickinson, Jesse; Levick, Lainie R.; Sugg, Zachary P.

    2016-08-18

    This study assessed progress toward achieving sustainable groundwater use in the Sierra Vista Subwatershed of the Upper San Pedro Basin, Arizona, through evaluation of 14 indicators of sustainable use. Sustainable use of groundwater in the Sierra Vista Subwatershed requires, at a minimum, a stable rate of groundwater discharge to, and thus base flow in, the San Pedro River. Many of the 14 indicators are therefore related to long-term or short-term effects on base flow and provide us with a means to evaluate groundwater discharge to and base flow in the San Pedro River. The indicators were based primarily on 10 to 20 years of data monitoring in the subwatershed, ending in 2012, and included subwatershedwide indicators, riparian-system indicators, San Pedro River indicators, and springs indicators.

  17. Ground-Water Quality Data in the Coastal Los Angeles Basin Study Unit, 2006: Results from the California GAMA Program

    Science.gov (United States)

    Mathany, Timothy M.; Land, Michael; Belitz, Kenneth

    2008-01-01

    Ground-water quality in the approximately 860 square-mile Coastal Los Angeles Basin study unit (CLAB) was investigated from June to November of 2006 as part of the Statewide Basin Assessment Project of the Ground-Water Ambient Monitoring and Assessment (GAMA) Program. The GAMA Statewide Basin Assessment was developed in response to the Ground-Water Quality Monitoring Act of 2001, and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The Coastal Los Angeles Basin study was designed to provide a spatially unbiased assessment of raw ground-water quality within CLAB, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 69 wells in Los Angeles and Orange Counties. Fifty-five of the wells were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study area (?grid wells?). Fourteen additional wells were selected to evaluate changes in ground-water chemistry or to gain a greater understanding of the ground-water quality within a specific portion of the Coastal Los Angeles Basin study unit ('understanding wells'). Ground-water samples were analyzed for: a large number of synthetic organic constituents [volatile organic compounds (VOCs), gasoline oxygenates and their degradates, pesticides, polar pesticides, and pesticide degradates, pharmaceutical compounds, and potential wastewater-indicators]; constituents of special interest [perchlorate, N-nitrosodimethylamine (NDMA), 1,4-dioxane, and 1,2,3-trichloropropane (1,2,3-TCP)]; inorganic constituents that can occur naturally [nutrients, major and minor ions, and trace elements]; radioactive constituents [gross-alpha and gross-beta radiation, radium isotopes, and radon-222]; and microbial indicators. Naturally occurring isotopes [stable isotopic ratios of hydrogen and oxygen, and activities of tritium and carbon-14

  18. Using Clumped Isotopes to Investigate the Causes of Pluvial Conditions in the Southeastern Basin and Range during the Last Deglaciation

    Science.gov (United States)

    Kowler, A.; Lora, J. M.; Mitchell, J.; Risi, C.; Lee, H. I.; Tripati, A.

    2015-12-01

    The last deglacial interval (~19-11 ka) was marked by major perturbations to Earth's climate coupled with rising atmospheric temperatures and CO2 concentrations, reaching near-modern levels by the early Holocene. Several discharges of freshwater into the North Atlantic caused by melting and collapse of continental ice sheets affected ocean circulation and sea-surface temperatures, triggering abrupt changes in terrestrial climate worldwide. While the timing and amount of associated temperature changes have been quantified from ice core records at high latitudes, corresponding information from lower latitudes is comparatively low and concentrated along coastlines, at high elevations, and in tropical and mesic regions. This is problematic for efforts to improve the reliability of long-term climate forecasts, reliant on models lacking sufficient validation from paleoclimate reconstructions for interior drylands that comprise nearly half of Earth's land surface. Evidence for past hydrologic changes in arid regions comes from ancient lake-shoreline deposits in internally drained basins, allowing quantitative comparison of the recorded effective moisture increases. However, the utility of these records depends on our relatively limited ability to deconvolve the contributions of temperature and precipitation to these changes. Here we explore the possible role of the summer monsoon in causing deglacial-age highstands in the southern Basin and Range. We employ clumped isotope analysis to generate paleotemperature and surface-water d18O estimates from carbonates in fossil shoreline and wetland deposits for comparison to output from PMIP3 coupled climate models and the model ensemble. Additionally, we present higher resolution output from LMDZ, the atmosphere-only component of the IPSL coupled model, employing LGM boundary conditions along with a hosing experiment designed to simulate Heinrich 1. For all simulations, we present analysis of changes in moisture transport

  19. Mapping Ground Water in Three Dimensions - An Analysis of Airborne Geophysical Surveys of the Upper San Pedro River Basin, Cochise County, Southeastern Arizona

    Science.gov (United States)

    Wynn, Jeff

    2006-01-01

    This report summarizes the results of two airborne geophysical surveys conducted in the upper San Pedro Valley of southeastern Arizona in 1997 and 1999. The combined surveys cover about 1,000 square kilometers and extend from the Huachuca Mountains on the west to the Mule Mountains and Tombstone Hills on the east and from north of the Babocomari River to near the Mexican border on the south. The surveys included the acquisition of high-resolution magnetic data, which were used to map depth to the crystalline basement rocks underlying the sediments filling the basin. The magnetic inversion results show a complex basement morphology, with sediment thickness in the center of the valley ranging from ~237 meters beneath the city of Sierra Vista to ~1,500 meters beneath Huachuca City and the Palominas area near the Mexican border. The surveys also included acquisition of 60-channel time-domain electromagnetic (EM) data. Extensive quality analyses of these data, including inversion to conductivity vs. depth (conductivity-depth-transform or CDT) profiles and comparisons with electrical well logs, show that the electrical conductor mapped represents the subsurface water-bearing sediments throughout most of the basin. In a few places (notably the mouth of Huachuca Canyon), the reported water table lies above where the electrical conductor places it. These exceptions appear to be due to a combination of outdated water-table information, significant horizontal displacement between the wells and the CDT profiles, and a subtle calibration issue with the CDT algorithm apparent only in areas of highly resistive (very dry) overburden. These occasional disparities appear in less than 5 percent of the surveyed area. Observations show, however, that wells drilled in the thick unsaturated zone along the Huachuca Mountain front eventually intersect water, at which point the water rapidly rises high into the unsaturated zone within the wellbore. This rising of water in a wellbore implies

  20. Changes of lead and barium with time in California off-shore basin sediments

    Science.gov (United States)

    No, Amy; Patterson, Clair C.

    1982-11-01

    During ancient times the natural deposition fluxes of lead which can be leached with dilute acid from sediments in Santa Barbara, Santa Monica and San Pedro basins offshore from the Los Angeles Urban complex, were about 0.7, 0.1 and 0.2 μg Pb/cm 2 yr respectively. Since there was little difference in biological productivity in surface waters of these basins, it is proposed that clay is a major transport vehicle for sequestered soluble lead, which then explains why the lead deposition flux within the Santa Barbara basin was so much larger compared to the other basins. The fluxes of silicate mud in the basins in ancient times were about 92, 19 and 30 mg/cm 2 yr in Santa Barbara, Santa Monica and San Pedro basins respectively. Today deposition fluxes of acid soluble lead within these three basins are 3- to 9-fold greater, being about 2.1, 1.1 and 1.8 μg Pb/cm 2 yr respectively, partly in the form of directly deposited large sewage particles, which account for none, 2/3 and 3/4 of the total industrial lead deposition fluxes in the respective basins. Concentrations of leachable lead in varve dated sediment layers increase with time and isotopic compositions of these leads change in accordance with corresponding known changes of isotopic compositions of industrial lead in the Los Angeles atmosphere. Lead remaining in acid leached sediment residues originates from igneous and clay minerals, exhibiting no change in concentration or isotopic composition since pre-industrial times. Deposition fluxes of total barium in sediments among the three basins were proportional to mass deposition fluxes before 1950 in the same manner as for lead. Afterwards, there are barium concentration maxima with time in both Santa Monica and San Pedro Basin sediments which are attributable to industrial sewage rather than to episodic erosion from barium-rich sedimentary evaporite strata exposed locally along the shore. An increase of barium concentrations in present day Santa Barbara basin

  1. Direct and indirect evidence for earthquakes; an example from the Lake Tahoe Basin, California-Nevada

    Science.gov (United States)

    Maloney, J. M.; Noble, P. J.; Driscoll, N. W.; Kent, G.; Schmauder, G. C.

    2012-12-01

    High-resolution seismic CHIRP data can image direct evidence of earthquakes (i.e., offset strata) beneath lakes and the ocean. Nevertheless, direct evidence often is not imaged due to conditions such as gas in the sediments, or steep basement topography. In these cases, indirect evidence for earthquakes (i.e., debris flows) may provide insight into the paleoseismic record. The four sub-basins of the tectonically active Lake Tahoe Basin provide an ideal opportunity to image direct evidence for earthquake deformation and compare it to indirect earthquake proxies. We present results from high-resolution seismic CHIRP surveys in Emerald Bay, Fallen Leaf Lake, and Cascade Lake to constrain the recurrence interval on the West Tahoe Dollar Point Fault (WTDPF), which was previously identified as potentially the most hazardous fault in the Lake Tahoe Basin. Recently collected CHIRP profiles beneath Fallen Leaf Lake image slide deposits that appear synchronous with slides in other sub-basins. The temporal correlation of slides between multiple basins suggests triggering by events on the WTDPF. If correct, we postulate a recurrence interval for the WTDPF of ~3-4 k.y., indicating that the WTDPF is near its seismic recurrence cycle. In addition, CHIRP data beneath Cascade Lake image strands of the WTDPF that offset the lakefloor as much as ~7 m. The Cascade Lake data combined with onshore LiDAR allowed us to map the geometry of the WTDPF continuously across the southern Lake Tahoe Basin and yielded an improved geohazard assessment.

  2. Magnetostratigraphy and 230Th dating of a drill core from the southeastern Qaidam Basin: Salt lake evolution and tectonic implications

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    An-Dong Chen

    2018-05-01

    Full Text Available The Qarhan Salt Lake area is the Quaternary depocenter of the Qaidam Basin, and carries thick lacustrine sediments, as well as rich potassium and magnesium salt deposits. The abundant resources and thick sediments in this lake provide an ideal place for the study of biogas formation and preservation, salt lake evolution, and the uplift of the Tibetan Plateau. In this study, we attempt to construct a paleomagnetic and 230Th age model and to obtain information on tectonic activity and salt lake evolution through detailed studies on a 1300-m-long drill core (15DZK01 from the northwestern margin of the Qarhan Salt Lake area (Dongling Lake. Based on gypsum 230Th dating, the age of the uppermost clastic deposit was calculated to be around 0.052 Ma. The polarity sequence consist of 13 pairs of normal and reversed zones, which can be correlated with subchrons C2r.1r-C1n of the geomagnetic polarity timescale (GPTS 2012 (from ∼2.070 Ma to ∼0.052 Ma. Sedimentary characteristics indicate that Dongling Lake witnessed freshwater environment between ∼2.070 Ma and 1.546 Ma. During this period, the sedimentary record reflects primarily lakeshore, shallow-water and swamp environments, representing favourable conditions for the formation of hydrocarbon source rocks. Between 1.546 Ma and ∼0.052 Ma, the Dongling Lake was in sulphate deposition stage, which contrasts with the central Qarhan Salt Lake area, where this stage did not occur in the meantime. During this stage, Dongling Lake was in a shallow saltwater lake environment, but several periods of reduced salinity occurred during this stage. During the late Pleistocene at ∼0.052 Ma, the Dongling Lake experienced uplift due to tectonic activity, and saltwater migrated through the Sanhu Fault to the central Qarhan Salt Lake area, resulting in the absence of halite deposition stage. The residual saline water was concentrated into magnesium-rich brine due to the lack of freshwater, and few

  3. Structure of the Wagner Basin in the Northern Gulf of California From Interpretation of Seismic Reflexion Data

    Science.gov (United States)

    Gonzalez, M.; Aguilar, C.; Martin, A.

    2007-05-01

    The northern Gulf of California straddles the transition in the style of deformation along the Pacific-North America plate boundary, from distributed deformation in the Upper Delfin and Wagner basins to localized dextral shear along the Cerro Prieto transform fault. Processing and interpretation of industry seismic data adquired by Petroleos Mexicanos (PEMEX) allow us to map the main fault structures and depocenters in the Wagner basin and to unravel the way strain is transferred northward into the Cerro Prieto fault system. Seismic data records from 0.5 to 5 TWTT. Data stacking and time-migration were performed using semblance coefficient method. Subsidence in the Wagner basin is controlled by two large N-S trending sub-parallel faults that intersect the NNW-trending Cerro Prieto transform fault. The Wagner fault bounds the eastern margin of the basin for more than 75 km. This fault dips ~50° to the west (up to 2 seconds) with distinctive reflectors displaced more than 1 km across the fault zone. The strata define a fanning pattern towards the Wagner fault. Northward the Wagner fault intersects the Cerro Prieto fault at 130° on map view and one depocenter of the Wagner basin bends to the NW adjacent to the Cerro Prieto fault zone. The eastern boundary of the modern depocenter is the Consag fault, which extends over 100 km in a N-S direction with an average dip of ~50° (up to 2s) to the east. The northern segment of the Consag fault bends 25° and intersects the Cerro Prieto fault zone at an angle of 110° on map view. The acoustic basement was not imaged in the northwest, but the stratigraphic succession increases its thickness towards the depocenter of the Wagner basin. Another important structure is El Chinero fault, which runs parallel to the Consag fault along 60 km and possibly intersects the Cerro Prieto fault to the north beneath the delta of the Colorado River. El Chinero fault dips at low-angle (~30°) to the east and has a vertical offset of about 0

  4. Subsidence (2004-2009) in and near lakebeds of the Mojave River and Morongo groundwater basins, southwest Mojave Desert, California

    Science.gov (United States)

    Solt, Mike; Sneed, Michelle

    2014-01-01

    Subsidence, in the vicinity of dry lakebeds, within the Mojave River and Morongo groundwater basins of the southwest Mojave Desert has been measured by Interferometric Synthetic Aperture Radar (InSAR). The investigation has focused on determining the location, extent, and magnitude of changes in land-surface elevation. In addition, the relation of changes in land-surface elevation to changes in groundwater levels and lithology was explored. This report is the third in a series of reports investigating land-surface elevation changes in the Mojave and Morongo Groundwater Basins, California. The first report, U.S. Geological Survey (USGS) Water-Resources Investigations Report 03-4015 by Sneed and others (2003), describes historical subsidence and groundwater-level changes in the southwest Mojave Desert from 1969 to 1999. The second report, U.S. Geological Survey Water-Resources Investigations Report 07-5097, an online interactive report and map, by Sneed and Brandt (2007), describes subsidence and groundwater-level changes in the southwest Mojave Desert from 1999 to 2004. The purpose of this report is to document an updated assessment of subsidence in these lakebeds and selected neighboring areas from 2004 to 2009 as measured by InSAR methods. In addition, continuous Global Positioning System (GPS)(2005-10), groundwater level (1951-2010), and lithologic data, if available, were used to characterize compaction mechanisms in these areas. The USGS California Water Science Center’s interactive website for the Mojave River and Morongo groundwater basins was created to centralize information pertaining to land subsidence and water levels and to allow readers to access available data and related reports online. An interactive map of land subsidence and water levels in the Mojave River and Morongo groundwater basins displays InSAR interferograms, subsidence areas, subsidence contours, hydrographs, well information, and water-level contours. Background information, including

  5. Impacts of Land Use on Surface Water Quality in a Subtropical River Basin: A Case Study of the Dongjiang River Basin, Southeastern China

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    Jiao Ding

    2015-08-01

    Full Text Available Understanding the relationship between land use and surface water quality is necessary for effective water management. We estimated the impacts of catchment-wide land use on water quality during the dry and rainy seasons in the Dongjiang River basin, using remote sensing, geographic information systems and multivariate statistical techniques. The results showed that the 83 sites can be divided into three groups representing different land use types: forest, agriculture and urban. Water quality parameters exhibited significant variations between the urban-dominated and forest-dominated sites. The proportion of forested land was positively associated with dissolved oxygen concentration but negatively associated with water temperature, electrical conductivity, permanganate index, total phosphorus, total nitrogen, ammonia nitrogen, nitrate nitrogen and chlorophyll-a. The proportion of urban land was strongly positively associated with total nitrogen and ammonia nitrogen concentrations. Forested and urban land use had stronger impacts on water quality in the dry season than in the rainy season. However, agricultural land use did not have a significant impact on water quality. Our study indicates that urban land use was the key factor affecting water quality change, and limiting point-source waste discharge in urban areas during the dry season would be critical for improving water quality in the study area.

  6. Palynology, palynofacies and paleoenvironmental studies of the Late Devonian sediments of the Atiavi-1 well, Keta Basin, southeastern Ghana

    Science.gov (United States)

    Atta-Peters, David; Achaegakwo, Christopher A.

    2017-05-01

    Palynomorph and palynofacies analysis have been performed on 34 cutting samples from the Late Devonian sediments of the Atiavi-1 well in the Keta Basin. Five (5) palynofacies associations linked to different depositional environments have been identified based on the kerogen content in the samples. Palynofacies types Pf A, Pf B and Pf E reflect deposition under mud-dominated oxic shelf conditions (distal shelf), characterized by kerogen type III > IV which is gas prone. Palynofacies type C (Pf C) and D (Pf D) reflect heterolithic oxic shelf (proximal) conditions and are also characterized by type III or IV kerogen. The palynomorph associations (miospores, acritarchs and chitinozoans) indicate an offshore distal or outer shelf environment for the lower section (1490 m-1244 m) with the upper sections (1244 m-936 m) showing intermixing of land - derived elements (miospores, phytoclasts and cuticles) with minor amounts of acritarchs, which strongly suggests deposition in shallow marine/fluvio-deltaic environment. The abundance and diversity of spores is an indication of humid climatic condition which existed at the time of deposition. Palynomorphs with marker species based mainly on miospores assemblages and some diagnostic chitinozoans and acritarchs association from the Atiavi-1 well indicate an age of upper lower Devonian (Emsian) to latest Devonian (Strunian).

  7. Palynological age and palaeoenvironment of deposition of Mid-Cenozoic sediments around Umuahia, Niger delta basin, southeastern Nigeria

    Science.gov (United States)

    Ikegwuonu, Okechukwu N.; Umeji, Obianuji P.

    2016-05-01

    The sediments of Oligocene - Early Miocene Ogwashi Formation of the Niger Delta Basin exposed in the kaolinite quarry by Oyivo stream in Umuahia comprise four lithological units which from base to top are (a) white to grey mudstone over 5.0 m thick; (b) lignite 1.0 m; (c) carbonaceous grey to dark shale 3.0 m; and (d) medium to coarse grained argillaceous sandstone 8.5 m. Samples from lignite and carbonaceous shale yielded rich palynomorph assemblages. Argillaceous sandstone and mudstone were barren. Lignite recorded more spores and less pollen while carbonaceous shale had more pollen and less spores. Index sporomorphs include Verrucatosporites usmensis, Magnastriatites howardii, Psilatricolporites crassus, Echiperiporites icacinoides, Echiperiporites minor, Retibrevitricolporites protrudens, Retibrevitricolpo-rites obodoensis, Retibrevitricolporites ibadanensis, Chenopodipollis dispersus and Retitricolporites irregularis representing Oligocene - Early Miocene Verrucatosporites usmensis/Magnastriatites howardii pantropical palynozones. Palaeoenvironmental indicators include Monoporites annulatus, grass pollen commonly found in open vegetation of savannah or reed swamps within the rain forests; Psilastephanocolporites laevigatus, the tropical lowland evergreen tree; Proxapertites operculatus, Longapertites marginatus and Psilatricolporites crassus the palms of brackish water swamp, along with Schizosporis parvus (Spirogyra) a fresh-water green alga. The sporomorphs indicate palaeoenvironments ranging from fresh water upper to brackish water lower deltaic plain within the tropical rainforest.

  8. Biología reproductiva del bagre cominate Occidentarius platypogon (Pisces: Ariidae en el sureste del golfo de California Reproductive biology of the cominate sea catfish Occidentarius platypogon (Pisces: Ariidae from the southeastern Gulf of California

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    Felipe Amezcua

    2012-07-01

    Full Text Available En el sureste del golfo de California, el bagre cominate presenta gran abundancia y es explotado comercialmente. Sin embargo, estudios sobre su biología son escasos y no existen normas que regulen su explotación en México. En este trabajo se describe la biología reproductiva de Occidentarius platypogon. Se capturaron 480 organismos con redes agalleras entre octubre 2008 y diciembre 2009. El estado de madurez gonadal se determinó macroscópicamente. Esta especie tiene una época de desove de mayo a agosto con un desarrollo sincrónico en dos lotes. La fecundidad media fue de 37 ovocitos maduros. La baja fecundidad se debe a que esta especie presenta cuidado parental con incubación oral por parte de los machos, lo cual reduce su mortalidad natural en las primeras etapas de desarrollo. La talla de primera madurez fue de 37,6 cm y la longitud estimada de primera captura de la pesquería artesanal con redes de enmalle fue de 23,4 cm, lo que indica la captura de organismos que aún no alcanzan su talla reproductiva. La mayoría de los organismos capturados fueron machos incubando, por lo tanto, podría ser alta la mortalidad por pesca de juveniles.The cominate sea catfish from the southeastern Gulf of California is an important species that is commercially exploited. However, studies on biology of this species are scarce; therefore, harvest regulations do not exist for this species in Mexico. The aim of this work was to describe reproductive biology of Occidentarius platypogon. Gillnet samples were carried out from October 2008 to December 2009. In total, 480 fish were dissected; gender sex and gonad maturity stage were determined macroscopically. Results indicated that the spawning season runs from May to August and generally with synchronic gonad development. Fecundity of the chihuil sea catfish was 37, which is low because this species shows parental care via oral incubation of fry, reducing mortality. Estimated length at first maturity is 37

  9. Status and understanding of groundwater quality in the Sierra Nevada Regional study unit, 2008: California GAMA Priority Basin Project

    Science.gov (United States)

    Fram, Miranda S.; Belitz, Kenneth

    2014-01-01

    Groundwater quality in the Sierra Nevada Regional (SNR) study unit was investigated as part of the California State Water Resources Control Board’s Groundwater Ambient Monitoring and Assessment Program Priority Basin Project. The study was designed to provide statistically unbiased assessments of the quality of untreated groundwater within the primary aquifer system of the Sierra Nevada. The primary aquifer system for the SNR study unit was delineated by the depth intervals over which wells in the State of California’s database of public drinking-water supply wells are open or screened. Two types of assessments were made: (1) a status assessment that described the current quality of the groundwater resource, and (2) an evaluation of relations between groundwater quality and potential explanatory factors that represent characteristics of the primary aquifer system. The assessments characterize untreated groundwater quality, rather than the quality of treated drinking water delivered to consumers by water distributors.

  10. Characteristics and origin of the relatively high-quality tight reservoir in the Silurian Xiaoheba Formation in the southeastern Sichuan Basin

    Science.gov (United States)

    Gong, Xiaoxing; Shi, Zejin; Wang, Yong; Tian, Yaming; Li, Wenjie; Liu, Lei

    2017-01-01

    A mature understanding of the sandstone gas reservoir in the Xiaoheba Formation in the southeastern Sichuan Basin remains lacking. To assess the reservoir characteristics and the origin of the high-quality reservoir in the Xiaoheba Formation, this paper uses systematic field investigations, physical property analysis, thin section identification, scanning electron microscopy and electron microprobe methods. The results indicate that the Xiaoheba sandstone is an ultra-tight and ultra-low permeability reservoir, with an average porosity of 2.97% and an average permeability of 0.56×10−3 μm2. This promising reservoir is mainly distributed in the Lengshuixi and Shuangliuba regions and the latter has a relatively high-quality reservoir with an average porosity of 5.28% and average permeability of 0.53×10−3 μm2. The reservoir space comprises secondary intergranular dissolved pores, moldic pores and fractures. Microfacies, feldspar dissolution and fracture connectivity control the quality of this reservoir. The relatively weak compaction and cementation in the interbedded delta front distal bar and interdistributary bay microfacies indirectly protected the primary intergranular pores and enhanced late-stage dissolution. Late-stage potassium feldspar dissolution was controlled by the early-stage organic acid dissolution intensity and the distance from the hydrocarbon generation center. Early-stage fractures acted as pathways for organic acid migration and were therefore important factors in the formation of the reservoir. Based on these observations, the area to the west of the Shuangliuba and Lengshuixi regions has potential for gas exploration. PMID:28686735

  11. Characteristics and origin of the relatively high-quality tight reservoir in the Silurian Xiaoheba Formation in the southeastern Sichuan Basin.

    Directory of Open Access Journals (Sweden)

    Xiaoxing Gong

    Full Text Available A mature understanding of the sandstone gas reservoir in the Xiaoheba Formation in the southeastern Sichuan Basin remains lacking. To assess the reservoir characteristics and the origin of the high-quality reservoir in the Xiaoheba Formation, this paper uses systematic field investigations, physical property analysis, thin section identification, scanning electron microscopy and electron microprobe methods. The results indicate that the Xiaoheba sandstone is an ultra-tight and ultra-low permeability reservoir, with an average porosity of 2.97% and an average permeability of 0.56×10-3 μm2. This promising reservoir is mainly distributed in the Lengshuixi and Shuangliuba regions and the latter has a relatively high-quality reservoir with an average porosity of 5.28% and average permeability of 0.53×10-3 μm2. The reservoir space comprises secondary intergranular dissolved pores, moldic pores and fractures. Microfacies, feldspar dissolution and fracture connectivity control the quality of this reservoir. The relatively weak compaction and cementation in the interbedded delta front distal bar and interdistributary bay microfacies indirectly protected the primary intergranular pores and enhanced late-stage dissolution. Late-stage potassium feldspar dissolution was controlled by the early-stage organic acid dissolution intensity and the distance from the hydrocarbon generation center. Early-stage fractures acted as pathways for organic acid migration and were therefore important factors in the formation of the reservoir. Based on these observations, the area to the west of the Shuangliuba and Lengshuixi regions has potential for gas exploration.

  12. Water resources and effects of potential surface coal mining on dissolved solids in Hanging Woman Creek basin, southeastern Montana

    Science.gov (United States)

    Cannon, M.R.

    1989-01-01

    Groundwater resources of the Hanging Woman Creek basin, Montana include Holocene and Pleistocene alluvial aquifers and sandstone , coal, and clinker aquifers in the Paleocene Fort Union Formation. Surface water resources are composed of Hanging Woman Creek, its tributaries, and small stock ponds. Dissolved-solids concentrations in groundwater ranged from 200 to 11,00 mg/L. Generally, concentrations were largest in alluvial aquifers and smallest in clinker aquifers. Near its mouth, Hanging Woman Creek had a median concentration of about 1,800 mg/L. Mining of the 20-foot to 35-foot-thick Anderson coal bed and 3-foot to 16-foot thick Dietz coal bed could increase dissolved-solids concentrations in shallow aquifers and in Hanging Woman Creek because of leaching of soluble minerals from mine spoils. Analysis of saturated-paste extracts from 158 overburden samples indicated that water moving through mine spoils would have a median increase in dissolved-solids concentration of about 3,700 mg/L, resulting in an additional dissolved-solids load to Hanging Woman Creek of about 3.0 tons/day. Hanging Woman Creek near Birney could have an annual post-mining dissolved-solids load of 3,415 tons at median discharge, a 47% increase from pre-mining conditions load. Post-mining concentrations of dissolved solids, at median discharge, could range from 2,380 mg/L in March to 3,940 mg/L in August, compared to mean pre-mining concentrations that ranged from 1,700 mg/L in July, November, and December to 2,060 mg/L in May. Post-mining concentrations and loads in Hanging Woman Creek would be smaller if a smaller area were mined. (USGS)

  13. Regional water table (2016) in the Mojave River and Morongo groundwater basins, southwestern Mojave Desert, California

    Science.gov (United States)

    Dick, Meghan; Kjos, Adam

    2017-12-07

    From January to April 2016, the U.S. Geological Survey (USGS), the Mojave Water Agency, and other local water districts made approximately 1,200 water-level measurements in about 645 wells located within 15 separate groundwater basins, collectively referred to as the Mojave River and Morongo groundwater basins. These data document recent conditions and, when compared with older data, changes in groundwater levels. A water-level contour map was drawn using data measured in 2016 that shows the elevation of the water table and general direction of groundwater movement for most of the groundwater basins. Historical water-level data stored in the USGS National Water Information System (https://waterdata.usgs.gov/nwis/) database were used in conjunction with data collected for this study to construct 37 hydrographs to show long-term (1930–2016) and short-term (1990–2016) water-level changes in the study area.

  14. Modeling the oxidative capacity of the atmosphere of the south coast air basin of California. 2. HOx radical production.

    Science.gov (United States)

    Griffin, Robert J

    2004-02-01

    The production of HOx radicals in the South Coast Air Basin of California is investigated during the smog episode of September 9, 1993 using the California Institute of Technology (CIT) air-quality model. Sources of HOx(hydroxyl, hydroperoxy, and organic peroxy radicals) incorporated into the associated gas-phase chemical mechanism include the combination of excited-state singlet oxygen (formed from ozone (O3) photolysis (hv)) with water, the photolysis of nitrous acid, hydrogen peroxide (H2O2), and carbonyl compounds (formaldehyde (HCHO) or higher aldehydes and ketones), the consumption of aldehydes and alkenes (ALK) by the nitrate radical, and the consumption of alkenes by O3 and the oxygen atom (O). At a given time or location for surface cells and vertical averages, each route of HOx formation may be the greatest contributor to overall formation except HCHO-hv, H2O2-hv, and ALK-O, the latter two of which are insignificant pathways in general. The contribution of the ALK-O3 pathway is dependent on the stoichiometric yield of OH, but this pathway, at least for the studied smog episode, may not be as generally significant as previous research suggests. Future emissions scenarios yield lower total HOx production rates and a shift in the relative importance of individual pathways.

  15. Comparison of emission inventory and ambient concentration ratios of CO, NMOG, and NOx in California South Coast Air Basin

    International Nuclear Information System (INIS)

    Fujita, E.M.; Croes, B.E.; Bennett, C.L.; Lawson, D.R.; Lurmann, F.W.; Main, H.H.

    1992-01-01

    In the present study, the author performed a top-down validation of the reactive organic gas and carbon monoxide emission inventories for California's South Coast Air Basin by comparing speciation profiles for nonmethane organic gases (NMOG) and ratios of CO/NO x and NMOG/NO x derived from early-morning (0700 to 0800) ambient measurements taken during the 1987 Southern California Air Quality Study with the corresponding ratios and speciation profiles derived from day-specific, hourly, gridded emission inventories. Twenty separate comparisons were considered for each ratio, each representing a different combination of season, emission category, and spatial and temporal averaging of emissions. It was determined that the most appropriate comparison in summer was ambient pollutant ratios with ratios derived from morning on-road motrovehicle emission inventories, and in the fall, ambient ratios with ratios derived from overnight on-road motor vehicle emission inventories with some contribution from overnight stationary-source NO x emission inventories. From these comparisons, the ambient CO/CO x and NMOG/NO x ratios are about 1.5 and 2 to 2.5 times higher, respectively, than the corresponding inventory ratios. On the assumption that inventories of NO x emissions are reasonably correct, these results indicate that on-road motor vehicle CO and NMOG emissions are significantly underestimated. Comparisons of measured CO, NMOG, and NO x concentrations and CO/NO x and NMOG/NO x ratios with air quality model predictions obtained by the California Air Resources Board show similar differences

  16. Bivariate Drought Analysis Using Streamflow Reconstruction with Tree Ring Indices in the Sacramento Basin, California, USA

    Directory of Open Access Journals (Sweden)

    Jaewon Kwak

    2016-03-01

    Full Text Available Long-term streamflow data are vital for analysis of hydrological droughts. Using an artificial neural network (ANN model and nine tree-ring indices, this study reconstructed the annual streamflow of the Sacramento River for the period from 1560 to 1871. Using the reconstructed streamflow data, the copula method was used for bivariate drought analysis, deriving a hydrological drought return period plot for the Sacramento River basin. Results showed strong correlation among drought characteristics, and the drought with a 20-year return period (17.2 million acre-feet (MAF per year in the Sacramento River basin could be considered a critical level of drought for water shortages.

  17. Geochemical constraints on the petrogenesis of the pyroclastic rocks in Abakaliki basin (Lower Benue Rift), Southeastern Nigeria

    Science.gov (United States)

    Chukwu, Anthony; Obiora, Smart C.

    2018-05-01

    The pyroclastic rocks in the Cretaceous Abakaliki basin occur mostly as oval-shaped bodies, consisting of lithic/lava and vitric fragments. They are commonly characterized by parallel and cross laminations, as well contain xenoliths of shale, mudstone and siltstones from the older Asu River Group of Albian age. The rocks are basic to ultrabasic in composition, comprising altered alkali basalts, altered tuffs, minor lapillistones and agglomerates. The mineral compositions are characterized mainly by laths of calcic plagioclase, pyroxene (altered), altered olivines and opaques. Calcite, zeolite and quartz represent the secondary mineral constituents. Geochemically, two groups of volcaniclastic rocks, are distinguished: alkaline and tholeiitic rocks, both represented by fresh and altered rock samples. The older alkali basalts occur within the core of the Abakaliki anticlinorium while the younger tholeiites occur towards the periphery. Though most of the rocks are moderate to highly altered [Loss on ignition (LOI, 3.43-22.07 wt. %)], the use of immobile trace element such as Nb, Zr, Y, Hf, Ti, Ta and REEs reflect asthenospheric mantle source compositions. The rocks are enriched in incompatible elements and REEs (∑REE = 87.98-281.0 ppm for alkaline and 69.45-287.99 ppm for tholeiites). The ratios of La/Ybn are higher in the alkaline rocks ranging from 7.69 to 31.55 compared to the tholeiitic rocks which range from 4.4 to 16.89 and indicating the presence of garnet-bearing lherzolite in the source mantle. The spidergrams and REEs patterns along with Zr/Nb, Ba/Nb, Rb/Nb ratios suggest that the rocks were generated by a mantle plume from partial melting of mixed enriched mantle sources (HIMU, EMI and EMII) similar to the rocks of the south Atlantic Ocean such as St. Helena (alkaline rocks) and Ascension rocks (tholeiitic rocks). The rocks were formed in a within-plate setting of the intra-continental rift type similar to other igneous rocks in the Benue Rift and are not

  18. Mass movement and storms in the drainage basin of Redwood Creek, Humboldt County, California: a progress report

    Science.gov (United States)

    Harden, Deborah Reid; Janda, Richard J.; Nolan, K. Michael

    1978-01-01

    Numerous active landslides are clearly significant contributors to high sediment loads in the Redwood Creek basin. Field and aerial-photograph inspections indicate that large mass-movement features, such as earthflows and massive streamside debris slides, occur primarily in terrain underlain by unmetamorphosed or slightly metamorphosed sedimentary rocks. These features cannot account for stream sediment derived from schist. Observed lithologic heterogeneity of stream sediment therefore suggests that large-scale mass movement is only one part of a complex suite of processes supplying sediment to streams in this basin. Other significant sediment contributors include various forms of fluvial erosion and small-scale discrete mass failures, particularly on oversteepened hillslopes adjacent to perennial streams. Photo-interpretive studies of landslide and timber-harvest history adjacent to Redwood Creek, together with analysis of regional precipitation and runoff records for six flood-producing storms between 1953 and 1975, indicate that loci and times of significant streamside landsliding are influenced by both local storm intensity and streamside logging. Analysis of rainfall records and historic accounts indicates that the individual storms comprising a late-19th-century series of storms in northwestern California were similar in magnitude and spacing to those of the past 25 years. The recent storms apparently initiated more streamside landslides than comparable earlier storms, which occurred prior to extensive road construction and timber harvest. Field observations and repeated surveys of stake arrays at 10 sites in the basin indicate that earthflows are especially active during prolonged periods of moderate rainfall; but that during brief intense storms, fluvial processes are the dominant erosion mechanism. Stake movement occurs mostly during wet winter months. Spring and summer movement was detected at some moist streamside sites. Surveys of stake arrays in two

  19. Phreatophytic land-cover map of the northern and central Great Basin Ecoregion: California, Idaho, Nevada, Utah, Oregon, and Wyoming

    Science.gov (United States)

    Mathie, Amy M.; Welborn, Toby L.; Susong, David D.; Tumbusch, Mary L.

    2011-01-01

    Increasing water use and changing climate in the Great Basin of the western United States are likely affecting the distribution of phreatophytic vegetation in the region. Phreatophytic plant communities that depend on groundwater are susceptible to natural and anthropogenic changes to hydrologic flow systems. The purpose of this report is to document the methods used to create the accompanying map that delineates areas of the Great Basin that have the greatest potential to support phreatophytic vegetation. Several data sets were used to develop the data displayed on the map, including Shrub Map (a land-cover data set derived from the Regional Gap Analysis Program) and Gap Analysis Program (GAP) data sets for California and Wyoming. In addition, the analysis used the surface landforms from the U.S. Geological Survey (USGS) Global Ecosystems Mapping Project data to delineate regions of the study area based on topographic relief that are most favorable to support phreatophytic vegetation. Using spatial analysis techniques in a GIS, phreatophytic vegetation classes identified within Shrub Map and GAP were selected and compared to the spatial distribution of selected landforms in the study area to delineate areas of phreatophyte vegetation. Results were compared to more detailed studies conducted in selected areas. A general qualitative description of the data and the limitations of the base data determined that these results provide a regional overview but are not intended for localized studies or as a substitute for detailed field analysis. The map is intended as a decision-support aide for land managers to better understand, anticipate, and respond to ecosystem changes in the Great Basin.

  20. Bacterial sulfate reduction in hydrothermal sediments of the Guaymas Basin, Gulf of California, Mexico

    DEFF Research Database (Denmark)

    Weber, A.; Jørgensen, BB

    2002-01-01

    Depth distribution and temperature dependence of bacterial sulfate reduction were studied in hydrothermal surface sediments of the southern trough of the Guaymas Basin at 2000 m water depth. In situ temperatures ranged from 2.8 degreesC at the sediment surface to > 130degreesC at 30 cm depth in t...

  1. Heat Flow Budget of the Gulf of California Rift: Preliminary Results of a High Resolution Survey Across the Wagner Basin

    Science.gov (United States)

    Negrete-Aranda, R.; Neumann, F.; Harris, R. N.; Contreras, J.; Gonzalez-Fernandez, A.; Sclater, J. G.

    2016-12-01

    The thermal regime exerts a primary control on rift dynamics and mode of extension for continental lithosphere. We present three heat-flow profiles across the southern terminus of the Cerro Prieto fault, in the northern Gulf of California. The longest profile is 42 km and has a measurement spacing of 1 km that spans the hanging-wall block (Wagner basin) and the footwall block of that fault. Measurements were taken with a 6.5 m long Fielax, violin-bow probe. Most measurements are of good quality, i.e., the probe fully penetrated sediments and measurements were stable enough to perform reliable inversion for heat flow and thermal properties. However, it was necessary to perform numerous corrections due to environmental phenomena related the copious sedimentation in the area, and seasonal changes in water temperature. Our measurements indicate the total throughput across the central rift and its east shoulder is 15 KW/m per meter of rift length. More important, heat flow values cluster in three distinct spatial groups: (i) heat flow in the well sedimented depocenter of the Wagner basin is approximately 200 mW/m2; (ii) the footwall block heat-flow is approximately 400 mW/m2; and (iii) heat flow across the fault zone is very high, up to 5,000 mW/m2. Our interpretation is that the former value represents the background conductive heat flow in the rift whereas heat flow across the fault represents advective heat transport by hydrothermal fluids. The high heat flow in the footwall block of the Cerro Prieto fault might be result of both conductive and advective heat transfer by fluid seepage from the basin. These data provide evidence that fluids from deep magma bodies transported along faults assist rifting in the northern Gulf of California. We are exploring how fluids may play a role in weakening the lithosphere and help localizing/delocalizing strain along major transforms and numerous normal faults observed in the area.

  2. Syntectonic Deposition of Plio-Quaternary Sediments in the Santa Rosalia Basin of Baja California Sur, Mexico

    Science.gov (United States)

    Michels, A.; Johnson, L.; Niemi, T. M.

    2017-12-01

    Plio-Quaternary sediments of the Tirabuzón, Infierno, and Santa Rosalía formations record syntectonic deposition in the Santa Rosalía basin—an oblique-rift-margin basin along the Gulf of California in Baja California Sur, Mexico. These deposits unconformably overlie the upper Miocene, Cu-Zn-Co-Mn-rich Boleo Formation. The Mesa Soledad outcrops, exposed on the Minera Boleo mine property, show interfingering of marine and terrestrial deposits of the three formations along the inland margin of the basin in an area that has not previously been studied. Faults that cut the Pliocene section of the mesa are mostly steeply-dipping, NW- and NE-striking faults with normal displacement determined from stratigraphic offset and steep plunge in striations. Two stratigraphic sections were measured on either side of one of these high-angle, NW-striking fault that has a normal throw of 26 m. Our analyses of sediment grain size, fossil assemblages, and sedimentary petrography indicate a mismatch of the stratigraphic units across the fault and suggest a component of strike slip. North of the fault, poorly-sorted, well-rounded, fluvial gravels from the Pliocene-aged, Tirabuzón Formation unconformably underlie fossiliferous marine deposits from the late-Pliocene to Pleistocene? -aged Infierno Formation. South of the fault, marine deposits of the Tirabuzón Formation grade upward into imbricated, clast-supported beach gravel, and finally into non-marine conglomerates. The absence of the Infierno Formation on the southern side of the fault suggests the deposits were either eroded unevenly due to uplift or laterally displaced by strike-slip movement. Fossiliferous sandstones and conglomerates of the Santa Rosalía Formation unconformably cap the entire outcrop and show no displacement from faulting. The Santa Rosalía Formation is overlain by the 1.4 Ma La Reforma ignimbrite (Schmidt 2006), indicating that the style of deformation of the basin changed at approximately this time.

  3. Water Quality in the Santa Ana Basin, California, 1999-2001

    Science.gov (United States)

    Belitz, Kenneth; Hamlin, Scott N.; Burton, Carmen A.; Kent, Robert; Fay, Ronald G.; Johnson, Tyler D.

    2004-01-01

    This report contains the major findings of a 1999-2001 assessment of water quality in the Santa Ana River Basin. It is one of a series of reports by the National Water-Quality Assessment (NAWQA) Program that present major findings in 51 major river basins and aquifer systems across the Nation. In these reports, water quality is discussed in terms of local, State, and regional issues. Conditions in a particular basin or aquifer system are compared to conditions found elsewhere and to selected national benchmarks, such as those for drinking-water quality and the protection of aquatic organisms. This report is intended for individuals working with water-resource issues in Federal, State, or local agencies, universities, public interest groups, or in the private sector. The information will be useful in addressing a number of current issues, such as the effects of agricultural and urban land use on water quality, human health, drinking water, source-water protection, hypoxia and excessive growth of algae and plants, pesticide registration, and monitoring and sampling strategies. This report is also for individuals who wish to know more about the quality of streams and ground water in areas near where they live and how that water quality compares to other areas across the Nation. The water-quality conditions in the Santa Ana River Basin summarized in this report are discussed in detail in other reports that can be accessed from http://ca.water.usgs.gov/ sana_nawqa/. Detailed technical information, data and analyses, collection and analytical methodology, models, graphs, and maps that support the findings presented in this report in addition to other reports in this series from other basins can be accessed from the national NAWQA Web site (http://water.usgs.gov/nawqa).

  4. The Ups and Downs of extension-parallel folding: Stratigraphic evolution of a constrictional rift basin during oblique opening of the Gulf of California

    Science.gov (United States)

    Seiler, Christian; Quigley, Mark; Fletcher, John

    2013-04-01

    Oblique opening of the Gulf of California provides a unique opportunity to study the mode of deformation in transtensional rift systems. Sedimentation in rifted basins is primarily controlled by the characteristics of the basin-bounding fault and the available sediment supply, and can thus be used as a proxy to understand tectonic processes during oblique shear. Transtensional basins are generally seen as composites between rift and pull-apart basins, with facies distributions that are controlled by interacting normal and strike-slip faults. Yet, transtensional shear may also be accommodated by more distributed constrictional strain that is not localised along fault zones. The Santa Rosa basin, located in the Sierra San Felipe of northern Baja California, is one of a series of transtensional syn-rift basins along the oblique-divergent plate boundary of the northern Gulf of California. The basin represents an asymmetric half-graben in the hanging wall of the Santa Rosa detachment, a low-angle normal fault with ~4-5km of E- to SE-directed displacement. The basin-fill dips NW into the detachment and displays form lines that mimic the corrugations of the detachment. The basin is broadly sigmoidal in shape, is truncated in the south by a dextral transfer zone and pinches out against the hanging wall basement in the north. The syn-rift stratigraphy is dominated by a sequence of alluvial fans shed from the hanging wall and footwall that interfinger with fine grained playa deposits. Stratigraphic analysis reveals systematic basin-scale variations in facies distributions, both along and across the axis of the basin. In a transverse direction, the basin-fill records a fining-upward cycle from conglomerate at the base to alternating sandstone-mudstone in the depocentre, which in turn interfingers with the proximal fault-scarp facies of the Santa Rosa detachment. Facies patterns also vary parallel to the basin axis even though finite displacement on the detachment was

  5. Effects of Faults on Petroleum Fluid Dynamics, Borderland Basins of Southern California

    Science.gov (United States)

    Jung, B.; Garven, G.; Boles, J. R.

    2012-12-01

    Multiphase flow modeling provides a useful quantitative tool for understanding crustal processes such as petroleum migration in geological systems, and also for characterizing subsurface environmental issues such as carbon sequestration in sedimentary basins. However, accurate modeling of multi-fluid behavior is often difficult because of the various coupled and nonlinear physics affecting multiphase fluid saturation and migration, including effects of capillarity and relative permeability, anisotropy and heterogeneity of the medium, and the effects of pore pressure, composition, and temperature on fluid properties. Regional fault structures also play a strong role in controlling fluid pathlines and mobility, so considering hydrogeologic effects of these structures is critical for testing exploration concepts, and for predicting the fate of injected fluids. To address these issues on spatially large and long temporal scales, we have developed a 2-D multiphase fluid flow model, coupled to heat flow, using a hybrid finite element and finite volume method. We have had good success in applying the multiphase flow model to fundamental issues of long-distance petroleum migration and accumulation in the Los Angeles basin, which is intensely faulted and disturbed by transpressional tectonic stresses, and host to the world's richest oil accumulation. To constrain the model, known subsurface geology and fault structures were rendered using geophysical logs from industry exploration boreholes and published seismic profiles. Plausible multiphase model parameters were estimated, either from known fault permeability measurements in similar strata in the Santa Barbara basin, and from known formation properties obtained from numerous oil fields in the Los Angeles basin. Our simulations show that a combination of continuous hydrocarbon generation and primary migration from upper Miocene source rocks in the central LA basin synclinal region, coupled with a subsiding basin fluid

  6. Geohydrology, Geochemistry, and Ground-Water Simulation-Optimization of the Central and West Coast Basins, Los Angeles County, California

    Science.gov (United States)

    Reichard, Eric G.; Land, Michael; Crawford, Steven M.; Johnson, Tyler D.; Everett, Rhett; Kulshan, Trayle V.; Ponti, Daniel J.; Halford, Keith L.; Johnson, Theodore A.; Paybins, Katherine S.; Nishikawa, Tracy

    2003-01-01

    Historical ground-water development of the Central and West Coast Basins in Los Angeles County, California through the first half of the 20th century caused large water-level declines and induced seawater intrusion. Because of this, the basins were adjudicated and numerous ground-water management activities were implemented, including increased water spreading, construction of injection barriers, increased delivery of imported water, and increased use of reclaimed water. In order to improve the scientific basis for these water management activities, an extensive data collection program was undertaken, geohydrological and geochemical analyses were conducted, and ground-water flow simulation and optimization models were developed. In this project, extensive hydraulic, geologic, and chemical data were collected from new multiple-well monitoring sites. On the basis of these data and data compiled and collected from existing wells, the regional geohydrologic framework was characterized. For the purposes of modeling, the three-dimensional aquifer system was divided into four aquifer systems?the Recent, Lakewood, Upper San Pedro, and Lower San Pedro aquifer systems. Most pumpage in the two basins is from the Upper San Pedro aquifer system. Assessment of the three-dimensional geochemical data provides insight into the sources of recharge and the movement and age of ground water in the study area. Major-ion data indicate the chemical character of water containing less than 500 mg/L dissolved solids generally grades from calcium-bicarbonate/sulfate to sodium bicarbonate. Sodium-chloride water, high in dissolved solids, is present in wells near the coast. Stable isotopes of oxygen and hydrogen provide information on sources of recharge to the basin, including imported water and water originating in the San Fernando Valley, San Gabriel Valley, and the coastal plain and surrounding hills. Tritium and carbon-14 data provide information on relative ground-water ages. Water with

  7. Feasibility Report and Environmental Statement for Water Resources Development, Cache Creek Basin, California

    Science.gov (United States)

    1979-02-01

    classified as Porno , Lake Miwok, and Patwin. Recent surveys within the Clear Lake-Cache Creek Basin have located 28 archeological sites, some of which...additional 8,400 acre-feet annually to the Lakeport area. Porno Reservoir on Kelsey Creek, being studied by Lake County, also would supplement M&l water...project on Scotts Creek could provide 9,100 acre- feet annually of irrigation water. Also, as previously discussed, Porno Reservoir would furnish

  8. Shallow Miocene basaltic magma reservoirs in the Bahia de Los Angeles basin, Baja California, Mexico

    Science.gov (United States)

    Delgado-Argote, Luis A.; García-Abdeslem, Juan

    1999-01-01

    The basement in the Bahía de Los Angeles basin consists of Paleozoic metamorphic rocks and Cretaceous granitoids. The Neogene stratigraphy overlying the basement is formed, from the base to the top, by andesitic lava flows and plugs, sandstone and conglomeratic horizons, and Miocene pyroclastic flow units and basaltic flows. Basaltic dikes also intrude the whole section. To further define its structure, a detailed gravimetric survey was conducted across the basin about 1 km north of the Sierra Las Flores. In spite of the rough and lineal topography along the foothills of the Sierra La Libertad, we found no evidence for large-scale faulting. Gravity data indicates that the basin has a maximum depth of 120 m in the Valle Las Tinajas and averages 75 m along the gravimetric profile. High density bodies below the northern part of the Sierra Las Flores and Valle Las Tinajas are interpreted to be part of basaltic dikes. The intrusive body located north of the Sierra Las Flores is 2.5 km wide and its top is about 500 m deep. The lava flows of the top of the Sierra Las Flores, together with the distribution of basaltic activity north of this sierra, suggests that this intrusive body continues for 20 km along a NNW-trending strike. Between the sierras Las Flores and Las Animas, a 0.5-km-wide, 300-m-thick intrusive body is interpreted at a depth of about 100 m. This dike could be part of the basaltic activity of the Cerro Las Tinajas and the small mounds along the foothills of western Sierra Las Animas. The observed local normal faulting in the basin is inferred to be mostly associated with the emplacement of the shallow magma reservoirs below Las Flores and Las Tinajas.

  9. Air quality impacts of distributed power generation in the South Coast Air Basin of California 1: Scenario development and modeling analysis

    Science.gov (United States)

    Rodriguez, M. A.; Carreras-Sospedra, M.; Medrano, M.; Brouwer, J.; Samuelsen, G. S.; Dabdub, D.

    Distributed generation (DG) is generally defined as the operation of many small stationary power generators throughout an urban air basin. Although DG has the potential to supply a significant portion of the increased power demands in California and the rest of the United States, it may lead to increased levels of in-basin pollutants and adversely impact urban air quality. This study focuses on two main objectives: (1) the systematic characterization of DG installation in urban air basins, and (2) the simulation of potential air quality impacts using a state-of-the-art three-dimensional computational model. A general and systematic approach is devised to construct five realistic and 21 spanning scenarios of DG implementation in the South Coast Air Basin (SoCAB) of California. Realistic scenarios reflect an anticipated level of DG deployment in the SoCAB by the year 2010. Spanning scenarios are developed to determine the potential impacts of unexpected outcomes. Realistic implementations of DG in the SoCAB result in small differences in ozone and particulate matter concentrations in the basin compared to the baseline simulations. The baseline accounts for population increase, but does not consider any future emissions control measures. Model results for spanning implementations with extra high DG market penetration show that domain-wide ozone peak concentrations increase significantly. Also, air quality impacts of spanning implementations when DG operate during a 6-h period are larger than when the same amount of emissions are introduced during a 24-h period.

  10. Morphometric Discharge Relationships in the Cosumnes River Drainage Basin, Sierra Nevada, California

    Science.gov (United States)

    Cornwell, K.; Meyer, R.

    2002-12-01

    Hydrographic similarities between disparate gaging stations in the Consumnes River drainage basin suggest that it may be possible to extend stream gage records in areas with limited or missing records. This has led to an analysis of the relationship between recorded daily discharge values and bankfull channel conditions in the basin using USGS gage data from three sites in the basin [11335000 Cosumnes River at Michigan Bar (MBAR - period of record 1907-2002), 11333500 North Fork Cosumnes near El Dorado (NFELDO - period of record 1911-1941 and 1948-1987) and the 11334200 Middle Fork Cosumnes near Somerset (MFSOM - period of record 1957-1971)], 3-day mean discharge values and bank-full conditions (discharge recurrence interval of ~1.5 years) were calculated. Utilizing the bank-full discharge of the mainstem gage (MBAR) as a threshold, we compared discharge values between MBAR and two of its tributaries (NFELDO and MFSOM) and observed strong linear trends in the data sets. Mathematical expressions were derived to characterize the relations between the individual tributaries and the mainstem gage. When calibrated against the complete gage records of the tributaries we encountered overall error rates of less than 5 percent from both tributary data sets. This suggests that it is possible to extend stream gage records in areas with limited existing records or where occasional activiation and de-activation of gage sites result in incomplete long-term records.

  11. Groundwater recharge estimates of the Indian Wells Basin (California) using geochemical analysis of tritium

    Science.gov (United States)

    Faulkner, K. E.; Hagedorn, K. B.

    2017-12-01

    Quantifying recharge in groundwater basins located in an arid climate is difficult due to the effects of evapotranspiration and generally low rates of inflow. Constraining recharge for the Indian Wells Valley (IWV) will allow a more refined assessment of groundwater sustainability in the basin. In this study, a well-mixed reservoir model, the decay rate of tritium, groundwater tritium data acquired from USGS, and atmospheric tritium data acquired from IAEA allow for calculation of renewal rate within IWV. The resulting renewal rate throughout the basin show correlation to travel time from the source of recharge to the measurement location in keeping with the well-mixed reservoir model. The renewal rate can be used with porosity and effective aquifer thickness to generate recharge rates ranging from 4.7 cm/yr to 10 cm/yr. Refinement of the porosity and effective aquifer thickness values at each sample location is necessary to constrain recharge rates. Groundwater modeling generated recharge rates (9.32 cm/yr) fall within this range. These results are in keeping with the well-mixed aquifer model and fall within a reasonable range for an arid climate, which shows the applicability of the method.

  12. Temperature, salinity, radioisotopes, sediments, and other data from Phase II Outer Continental Shelf (OCS) Monitoring Program in the Santa Maria Basin, California from 21 Oct 1986 to 08 Mar 1987 (NODC Accession 8900198)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are part of the data collected for the California Phase II OCS Monitoring Program of the Santa Maria Basin by Dr. Hyland from Battelle Ocean Science and...

  13. Production, exportation and preservation of silicoflagellates in Alfonso Basin, Gulf of California

    Science.gov (United States)

    Martínez-López, Aída; Álvarez-Gómez, Irela G.; Pérez-Cruz, Ligia; Verdugo-Díaz, Gerardo; Villegas-Aguilera, María Magdalena

    2016-03-01

    Limited areas of sea floor have the physiochemical conditions that allow for the formation and preservation of high resolution (yearly or close to yearly) laminated sediments that can function as a historic proxy for past oceanographic and climate conditions. We evaluated and established the fidelity of the sedimentary record in recording these signals by analyzing silicoflagellates production, changes in species composition, skeletal settling and their subsequent burial in bottom sediments at Alfonso Basin. The data series from December 2005 to February 2008 showed similar tendencies in both the vertical flux and overlying euphotic zone (Zeu) production of silicoflagellates. Both series were numerically dominated by Octactis pulchra with maxima values being recorded for the mixed water column period. Observed differences occurred during the studied years in both magnitude and in flux composition. The presence of a mixed assemblage with (warm-temperate-cold) species such as Dictyocha fibula var. robusta, Dictyocha epiodon and Distephanus speculum could be explained by a synchronization of trends between a predominantly positive Pacific Decadal Oscillation and a positive North Pacific Gyre Oscillation climate phases that were the background conditions underlying the early 2006 through 2007 El Niño event. A Morisita's similarity index value of 97.5% between winter trap and Zeu samples combined with an annualized settling factor of 0.45, suggests that Alfonso Basin is a favorable settling environment for silicoflagellates. However, core-top sediments showed an attenuation of record fidelity (burial factor = 0.25) resulting in a modified record for the production and settling of skeletons. O. pulchra that were not preserved in sediments as the dominant species and with this removal, the signal was also lost of the highest silicoflagellate production season (Mixing-cyclonic eddy periods) from the sedimentary record of the Alfonso Basin.

  14. Stratigraphic record of Pliocene-Pleistocene basin evolution and deformation within the Southern San Andreas Fault Zone, Mecca Hills, California

    Science.gov (United States)

    McNabb, James C.; Dorsey, Rebecca J.; Housen, Bernard A.; Dimitroff, Cassidy W.; Messé, Graham T.

    2017-11-01

    A thick section of Pliocene-Pleistocene nonmarine sedimentary rocks exposed in the Mecca Hills, California, provides a record of fault-zone evolution along the Coachella Valley segment of the San Andreas fault (SAF). Geologic mapping, measured sections, detailed sedimentology, and paleomagnetic data document a 3-5 Myr history of deformation and sedimentation in this area. SW-side down offset on the Painted Canyon fault (PCF) starting 3.7 Ma resulted in deposition of the Mecca Conglomerate southwest of the fault. The lower member of the Palm Spring Formation accumulated across the PCF from 3.0 to 2.6 Ma during regional subsidence. SW-side up slip on the PCF and related transpressive deformation from 2.6 to 2.3 Ma created a time-transgressive angular unconformity between the lower and upper members of the Palm Spring Formation. The upper member accumulated in discrete fault-bounded depocenters until initiation of modern deformation, uplift, and basin inversion starting at 0.7 Ma. Some spatially restricted deposits can be attributed to the evolution of fault-zone geometric complexities. However, the deformation events at ca. 2.6 Ma and 0.7 Ma are recorded regionally along 80 km of the SAF through Coachella Valley, covering an area much larger than mapped fault-zone irregularities, and thus require regional explanations. We therefore conclude that late Cenozoic deformation and sedimentation along the SAF in Coachella Valley has been controlled by a combination of regional tectonic drivers and local deformation due to dextral slip through fault-zone complexities. We further propose a kinematic link between the 2.6-2.3 Ma angular unconformity and a previously documented but poorly dated reorganization of plate-boundary faults in the northern Gulf of California at 3.3-2.0 Ma. This analysis highlights the potential for high-precision chronologies in deformed terrestrial deposits to provide improved understanding of local- to regional-scale structural controls on basin

  15. Late Neogene stratigraphy and tectonic control on facies evolution in the Laguna Salada Basin, northern Baja California, Mexico

    Science.gov (United States)

    Martín-Barajas, A.; Vázquez-Hernández, S.; Carreño, A. L.; Helenes, J.; Suárez-Vidal, F.; Alvarez-Rosales, J.

    2001-10-01

    The Laguna Salada Basin (LSB) in northeastern Baja California records late-Neogene marine incursions in the Salton Trough and progradation of the Colorado River delta. Early subsidence and subsequent tectonic erosion are related to evolution of the Sierra El Mayor detachment fault during late Miocene time (stratigraphy of uplifted blocks on the east-central margin of the Laguna Salada Basin and from three exploratory wells allows reconstruction of the main sedimentary and tectonic events. Marine mudstone and sandstone, and subordinate conglomerate of the Imperial Formation tectonically overlie metamorphic and granitic basement. Microfossils, lithology, and sedimentary structures in the Imperial Formation define Upper Miocene (<6 Ma) outer-shelf facies that grade up-section into inner-shelf and tide-dominated delta plain deposits of the ancient Colorado River. Lower Pliocene (˜4-2 Ma) reddish, sub-arkosic fluvial sandstone and siltstone of the Palm Spring Formation defines progradation of non-marine fluvio-deltaic deposits over the marine Imperial Formation. Continuous outcrops of the Palm Spring are less than 170-m thick, but correlative deposits are more than 570 m thick in the lower part of a 2400-m deep geothermal exploratory well on the eastern margin of LSB. Interfingering fluvial-sandstone deposits and prograding alluvial fanglomerates with coarse debris-flow and rock-avalanche deposits crudely mark the onset of vertical slip along the Laguna Salada fault and rapid uplift of Sierra Cucapa and Sierra El Mayor. Up to 2 km of Quaternary alluvial-fan and lacustrine deposits accumulated along the eastern margin of LSB, whereas lower subsidence rates produced a thinner sedimentary wedge over a ramp-like crystalline basement along the western margin. In early Pleistocene time (˜2-1 Ma), the Laguna Salada became progressively isolated from the Colorado River delta complex, and the Salton Trough by activity on the Elsinore and Laguna Salada fault zones.

  16. Water Budgets of the Walker River Basin and Walker Lake, California and Nevada

    Science.gov (United States)

    Lopes, Thomas J.; Allander, Kip K.

    2009-01-01

    The Walker River is the main source of inflow to Walker Lake, a closed-basin lake in west-central Nevada. The only outflow from Walker Lake is evaporation from the lake surface. Between 1882 and 2008, upstream agricultural diversions resulted in a lake-level decline of more than 150 feet and storage loss of 7,400,000 acre-feet. Evaporative concentration increased dissolved solids from 2,500 to 17,000 milligrams per liter. The increase in salinity threatens the survival of the Lahontan cutthroat trout, a native species listed as threatened under the Endangered Species Act. This report describes streamflow in the Walker River basin and an updated water budget of Walker Lake with emphasis on the lower Walker River basin downstream from Wabuska, Nevada. Water budgets are based on average annual flows for a 30-year period (1971-2000). Total surface-water inflow to the upper Walker River basin upstream from Wabuska was estimated to be 387,000 acre-feet per year (acre-ft/yr). About 223,000 acre-ft/yr (58 percent) is from the West Fork of the Walker River; 145,000 acre-ft/yr (37 percent) is from the East Fork of the Walker River; 17,000 acre-ft/yr (4 percent) is from the Sweetwater Range; and 2,000 acre-ft/yr (less than 1 percent) is from the Bodie Mountains, Pine Grove Hills, and western Wassuk Range. Outflow from the upper Walker River basin is 138,000 acre-ft/yr at Wabuska. About 249,000 acre-ft/yr (64 percent) of inflow is diverted for irrigation, transpired by riparian vegetation, evaporates from lakes and reservoirs, and recharges alluvial aquifers. Stream losses in Antelope, Smith, and Bridgeport Valleys are due to evaporation from reservoirs and agricultural diversions with negligible stream infiltration or riparian evapotranspiration. Diversion rates in Antelope and Smith Valleys were estimated to be 3.0 feet per year (ft/yr) in each valley. Irrigated fields receive an additional 0.8 ft of precipitation, groundwater pumpage, or both for a total applied-water rate

  17. Time-series measurements of settling particulate matter in Alfonso Basin, La Paz Bay, southwestern Gulf of California

    Science.gov (United States)

    Silverberg, Norman; Aguirre-Bahena, Fernando; Mucci, Alfonso

    2014-08-01

    More than 200 sediment trap samples were collected at 310 or 360 m depth during 2002-2009 from the center of the 410 m-deep Alfonso Basin in La Paz Bay, an arid, subtropical embayment of the southern Gulf of California. Sample splits were analyzed for total mass flux (TMF), particulate organic carbon (POC), inorganic carbon (CaCO3) and opal (biogenic silica BioSi). The lithogenic (Litho) and biogenic fluxes (Biogen), but especially the particulate organic matter (POM) and CaCO3, fluxes are relatively high compared with those recorded in a number of other coastal basins at depths less than ~500 m. The average yearly Litho fluxes (mean of 133±158 g m-2 yr-1) are well correlated with the frequency of strong wind gusts and reflect the relative proximity of the mooring to shore and the importance of eolian transport. The sedimentation patterns are influenced by monsoonal shifts-cool temperatures and strong northerly winds in late fall and winter sustain a well-mixed deep surface layer and high lithogenic fluxes, whereas progressive heating and relatively weak southerlies in summer and fall lead to a shallower, more-stratified surface layer with lower nutrient levels, limited productivity and generally low particulate fluxes. There is considerable interannual variability in the size of the various fluxes. This is likely related to a number of regional and internal factors whose timing, intensity and interactions remain to be resolved. Although there is an inverse relationship between SST and satellite-derived net primary production (NPP) estimates, no correlation was found between NPP and the POC, CaCO3 and BioSi fluxes (r20.05). Significant correlations (p<0.001) do exist, however, between the POC flux and the total mineral flux as well as with the CaCO3, Litho and BioSi fluxes (r=0.86, 0.82, 0.79 and 0.69, respectively). As suggested by the ballast ratio hypothesis, the strength of these correlations follows the relative density of the individual ballast components

  18. Status and understanding of groundwater quality in the San Francisco Bay groundwater basins, 2007—California GAMA Priority Basin Project

    Science.gov (United States)

    Parsons, Mary C.; Kulongoski, Justin T.; Belitz, Kenneth

    2013-01-01

    Groundwater quality in the approximately 620-square-mile (1,600-square-kilometer) San Francisco Bay study unit was investigated as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study unit is located in the Southern Coast Ranges of California, in San Francisco, San Mateo, Santa Clara, Alameda, and Contra Costa Counties. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory. The GAMA San Francisco Bay study was designed to provide a spatially unbiased assessment of the quality of untreated groundwater within the primary aquifer system, as well as a statistically consistent basis for comparing water quality throughout the State. The assessment is based on water-quality and ancillary data collected by the USGS from 79 wells in 2007 and is supplemented with water-quality data from the California Department of Public Health (CDPH) database. The primary aquifer system is defined by the depth interval of the wells listed in the CDPH database for the San Francisco Bay study unit. The quality of groundwater in shallower or deeper water-bearing zones may differ from that in the primary aquifer system; shallower groundwater may be more vulnerable to surficial contamination. The first component of this study, the status of the current quality of the groundwater resource, was assessed by using data from samples analyzed for volatile organic compounds (VOCs), pesticides, and naturally occurring inorganic constituents, such as major ions and trace elements. Water- quality data from the CDPH database also were incorporated for this assessment. This status assessment is intended to characterize the quality of groundwater resources within the primary aquifer system of the San Francisco Bay study unit, not the treated drinking water delivered to consumers by water

  19. A telemetric study of the movement patterns and habitat use of Rana muscosa, the mountain yellow-legged frog, in a high-elevation basin in Kings Canyon National Park, California

    Science.gov (United States)

    K.R. Matthews; K.L. Pope

    1999-01-01

    ABSTRACTS.–In a high-elevation (3470 m) lake basin (upper Dusy Basin) in Kings Canyon National Park, California, we used radio transmitters on 24 mountain yellow-legged frogs (Rana muscosa) to gather basic information on their movement patterns. Rana muscosa have declined throughout their range in the Sierra Nevada and restoration plans require information on their...

  20. Pesticides in surface water measured at select sites in the Sacramento River basin, California, 1996-1998

    Science.gov (United States)

    Domagalski, Joseph L.

    2000-01-01

    Pesticides were measured in one urban stream, one agricultural stream, one site on the Sacramento River, and one large flood control channel over a period of 18 months during 1996-1998. All sites were located within the Sacramento River Basin of California. Measurements were made on 83 pesticides or pesticide transformation products by either gas chromatography/mass spectrometry or by high performance liquid chromatography with ultraviolet light spectrometry. Some pesticides were detected frequently at the agricultural stream and downstream in the Sacramento River and at the flood control channel of the Sacramento River. These were pesticides related to rice farming (molinate, carbofuran, thiobencarb, and bentazon); herbicides used both agriculturally or for roadside maintenance (diuron, simazine, and metolachlor); or insecticides used on orchards and row corps (diazinon and chlorpyrifos). No pesticide concen-trations above enforceable water quality criteria were measured at either the agricultural site or the Sacramento River sites. In contrast to the agricul-tural site, insecticides used for household, lawn, or garden maintenance were the most frequently detected pesticides at the urban site. Diazinon, an organophosphate insecticide, exceeded recom-mended criteria for the protection of aquatic life, and the diazinon levels were frequently above known toxic levels for certain zooplankton species at the urban site. Because of the low discharge of the urban stream, pesticide concentrations were greatly diluted upon mixing with Sacramento River water.

  1. Potential impacts of climate warming on water supply reliability in the Tuolumne and Merced River Basins, California.

    Directory of Open Access Journals (Sweden)

    Michael Kiparsky

    Full Text Available We present an integrated hydrology/water operations simulation model of the Tuolumne and Merced River Basins, California, using the Water Evaluation and Planning (WEAP platform. The model represents hydrology as well as water operations, which together influence water supplied for agricultural, urban, and environmental uses. The model is developed for impacts assessment using scenarios for climate change and other drivers of water system behavior. In this paper, we describe the model structure, its representation of historical streamflow, agricultural and urban water demands, and water operations. We describe projected impacts of climate change on hydrology and water supply to the major irrigation districts in the area, using uniform 2 °C, 4 °C, and 6 °C increases applied to climate inputs from the calibration period. Consistent with other studies, we find that the timing of hydrology shifts earlier in the water year in response to temperature warming (5-21 days. The integrated agricultural model responds with increased water demands 2 °C (1.4-2.0%, 4 °C (2.8-3.9%, and 6 °C (4.2-5.8%. In this sensitivity analysis, the combination of altered hydrology and increased demands results in decreased reliability of surface water supplied for agricultural purposes, with modeled quantity-based reliability metrics decreasing from a range of 0.84-0.90 under historical conditions to 0.75-0.79 under 6 °C warming scenario.

  2. Modern Radiolarian (Polycystina) from Carmen Basin, Gulf of California, México: an ecological approach of the last 200 years

    Science.gov (United States)

    Escalante-Ruiz, A. R.; Perez-Cruz, L. L.; Barbara, L.; Schmidt, S.

    2013-12-01

    Different taxa of radiolarians are adapted to different ocean conditions such as temperature and productivity, and specific assemblages characterize water masses and upwelling environments. Radiolarians are very common fossils in open marine sediments and in the Gulf of California are well preserved. In deep water deposits in slope sediments of the southern Gulf, up to 50 percent of the coarse fraction may consist of radiolarians, except in areas where dilution by terrigenous material is high. In the central part, diatoms are quantitative much more important in the sediments. However, south of latitude 26 degrees N, biogenous silica is almost exclusively radiolarians. Thus, in order to reconstruct the environmental conditions (i.g. water masses and ocean circulation patterns) a laminated sequence (core DIPAL V C-33, with 40 cm long) was collected in the eastern Carmen Basin in the gulf, at 600 m depth were the oxygen minimum impinges on the slope. Two hundred continuous samples along the core were prepared for radiolarian research. Rich and relatively well-preserved fauna is found and 160 taxa have been identified. A preliminary analysis shows that the orders Nasellaria and Spumellaria represent around 70% and 30%, respectively, indicating a more nearly oceanic conditions. Preliminary model age based on 210Pb dates indicates a sedimentation rate of 1.9 mm/yr, thus the core covers the past c. 200 years. Ecological diversity indices and statistical analysis are considered for the interpretation of radiolarian records and environmental reconstruction.

  3. The 2015 Fillmore earthquake swarm and possible crustal deformation mechanisms near the bottom of the eastern Ventura Basin, California

    Science.gov (United States)

    Hauksson, Egill; Andrews, Jennifer; Plesch, Andreas; Shaw, John H.; Shelly, David R.

    2016-01-01

    The 2015 Fillmore swarm occurred about 6 km west of the city of Fillmore in Ventura, California, and was located beneath the eastern part of the actively subsiding Ventura basin at depths from 11.8 to 13.8 km, similar to two previous swarms in the area. Template‐matching event detection showed that it started on 5 July 2015 at 2:21 UTC with an M∼1.0 earthquake. The swarm exhibited unusual episodic spatial and temporal migrations and unusual diversity in the nodal planes of the focal mechanisms as compared to the simple hypocenter‐defined plane. It was also noteworthy because it consisted of >1400 events of M≥0.0, with M 2.8 being the largest event. We suggest that fluids released by metamorphic dehydration processes, migration of fluids along a detachment zone, and cascading asperity failures caused this prolific earthquake swarm, but other mechanisms (such as simple mainshock–aftershock stress triggering or a regional aseismic creep event) are less likely. Dilatant strengthening may be a mechanism that causes the temporal decay of the swarm as pore‐pressure drop increased the effective normal stress, and counteracted the instability driving the swarm.

  4. Potential impacts of climate warming on water supply reliability in the Tuolumne and Merced River Basins, California.

    Science.gov (United States)

    Kiparsky, Michael; Joyce, Brian; Purkey, David; Young, Charles

    2014-01-01

    We present an integrated hydrology/water operations simulation model of the Tuolumne and Merced River Basins, California, using the Water Evaluation and Planning (WEAP) platform. The model represents hydrology as well as water operations, which together influence water supplied for agricultural, urban, and environmental uses. The model is developed for impacts assessment using scenarios for climate change and other drivers of water system behavior. In this paper, we describe the model structure, its representation of historical streamflow, agricultural and urban water demands, and water operations. We describe projected impacts of climate change on hydrology and water supply to the major irrigation districts in the area, using uniform 2 °C, 4 °C, and 6 °C increases applied to climate inputs from the calibration period. Consistent with other studies, we find that the timing of hydrology shifts earlier in the water year in response to temperature warming (5-21 days). The integrated agricultural model responds with increased water demands 2 °C (1.4-2.0%), 4 °C (2.8-3.9%), and 6 °C (4.2-5.8%). In this sensitivity analysis, the combination of altered hydrology and increased demands results in decreased reliability of surface water supplied for agricultural purposes, with modeled quantity-based reliability metrics decreasing from a range of 0.84-0.90 under historical conditions to 0.75-0.79 under 6 °C warming scenario.

  5. Governing change: land-use change and the prevention of nonpoint source pollution in the north coastal basin of California.

    Science.gov (United States)

    Short, Anne G

    2013-01-01

    Many rural areas in the United States and throughout much of the postindustrial world are undergoing significant ecological, socioeconomic, and political transformations. The migration of urban and suburban dwellers into rural areas has led to the subdivision of large tracts of land into smaller parcels, which can complicate efforts to govern human-environmental problems. Non-point source (NPS) pollution from private rural lands is a particularly pressing human-environmental challenge that may be aggravated by changing land tenure. In this article, I report on a study of the governance and management of sediment (a common NPS pollutant) in the North Coastal basin of California, a region undergoing a transition from traditional extractive and agricultural land uses to rural residential and other alternative land uses. I focus on the differences in the governance and management across private timber, ranch, residential, vacation, and other lands in the region. I find that (1) the stringency and strength of sediment regulations differ by land use, (2) nonregulatory programs tend to target working landscapes, and (3) rural residential landowners have less knowledge of sediment control and report using fewer sediment-control techniques than landowners using their land for timber production or ranching. I conclude with an exploration of the consequences of these differences on an evolving rural landscape.

  6. Controls on surface water chemistry in the upper Merced River basin, Yosemite National Park, California

    Science.gov (United States)

    Clow, D.W.; Mast, M.A.; Campbell, D.H.

    1996-01-01

    Surface water draining granitic bedrock in Yosemite National Park exhibits considerable variability in chemical composition, despite the relative homogeneity of bedrock chemistry. Other geological factors, including the jointing and distribution of glacial till, appear to exert strong controls on water composition. Chemical data from three surface water surveys in the upper Merced River basin conducted in August 1981, June 1988 and August 1991 were analysed and compared with mapped geological, hydrological and topographic features to identify the solute sources and processes that control water chemistry within the basin during baseflow. Water at most of the sampling sites was dilute, with alkalinities ranging from 26 to 77 ??equiv. 1-1. Alkalinity was much higher in two subcatchments, however, ranging from 51 to 302 ??equiv. 1-1. Base cations and silica were also significantly higher in these two catchments than in the rest of the watershed. Concentrations of weathering products in surface water were correlated to the fraction of each subcatchment underlain by surficial material, which is mostly glacial till. Silicate mineral weathering is the dominant control on concentrations of alkalinity, silica and base cations, and ratios of these constituents in surface water reflect the composition of local bedrock, Chloride concentrations in surface water samples varied widely, ranging from Merced River at the Happy Isles gauge from 1968 to 1990 was 26 ??equiv. 1-1, which was five times higher than in atmospheric deposition (4-5 ??equiv. 1-1), suggesting that a source of chloride exists within the watershed. Saline groundwater springs, whose locations are probably controlled by vertical jointing in the bedrock, are the most likely source of the chloride. Sulphate concentrations varied much less than most other solutes, ranging from 3 to 14 ??equiv. 1-1. Concentrations of sulphate in quarterly samples collected at the watershed outlet also showed relatively little variation

  7. Ground-Water Quality Data in the Central Eastside San Joaquin Basin 2006: Results from the California GAMA Program

    Science.gov (United States)

    Landon, Matthew K.; Belitz, Kenneth

    2008-01-01

    Ground-water quality in the approximately 1,695-square-mile Central Eastside study unit (CESJO) was investigated from March through June 2006 as part of the Statewide Basin Assessment Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Statewide Basin Assessment project was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the California State Water Resources Control Board (SWRCB) in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory (LLNL). The study was designed to provide a spatially unbiased assessment of raw ground-water quality within CESJO, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 78 wells in Merced and Stanislaus Counties. Fifty-eight of the 78 wells were selected using a randomized grid-based method to provide statistical representation of the study unit (grid wells). Twenty of the wells were selected to evaluate changes in water chemistry along selected lateral or vertical ground-water flow paths in the aquifer (flow-path wells). The ground-water samples were analyzed for a large number of synthetic organic constituents [volatile organic compounds (VOCs), gasoline oxygenates and their degradates, pesticides and pesticide degradates], constituents of special interest [perchlorate, N-nitrosodimethylamine (NDMA), and 1,2,3-trichloropropane (1,2,3-TCP)], inorganic constituents that can occur naturally [nutrients, major and minor ions, and trace elements], radioactive constituents, and microbial indicators. Naturally occurring isotopes [tritium, carbon-14, and uranium isotopes and stable isotopes of hydrogen, oxygen, nitrogen, sulfur, and carbon], and dissolved noble and other gases also were measured to help identify the source and age of the sampled ground water. Quality-control samples (blanks, replicates, samples for matrix spikes) were collected

  8. Status and understanding of groundwater quality in the San Diego Drainages Hydrogeologic Province, 2004: California GAMA Priority Basin Project

    Science.gov (United States)

    Wright, Michael T.; Belitz, Kenneth

    2011-01-01

    Groundwater quality in the approximately 3,900-square-mile (mi2) San Diego Drainages Hydrogeologic Province (hereinafter San Diego) study unit was investigated from May through July 2004 as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study unit is located in southwestern California in the counties of San Diego, Riverside, and Orange. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory. The GAMA San Diego study was designed to provide a statistically robust assessment of untreated-groundwater quality within the primary aquifer systems. The assessment is based on water-quality and ancillary data collected by the USGS from 58 wells in 2004 and water-quality data from the California Department of Public Health (CDPH) database. The primary aquifer systems (hereinafter referred to as the primary aquifers) were defined by the depth interval of the wells listed in the California Department of Public Health (CDPH) database for the San Diego study unit. The San Diego study unit consisted of four study areas: Temecula Valley (140 mi2), Warner Valley (34 mi2), Alluvial Basins (166 mi2), and Hard Rock (850 mi2). The quality of groundwater in shallow or deep water-bearing zones may differ from that in the primary aquifers. For example, shallow groundwater may be more vulnerable to surficial contamination than groundwater in deep water-bearing zones. This study had two components: the status assessment and the understanding assessment. The first component of this study-the status assessment of the current quality of the groundwater resource-was assessed by using data from samples analyzed for volatile organic compounds (VOC), pesticides, and naturally occurring inorganic constituents, such as major ions and trace elements. The status assessment is intended to

  9. Rates and patterns of sediment deposition in the Salinas River basin, Central California

    Science.gov (United States)

    Watson, E. B.; Pasternack, G.; Gray, A. B.; Pakenham, A.; Wheatcroft, R.; Goni, M. A.

    2008-12-01

    Erosion rates in mountainous watersheds have increased during historic times due to land use changes such as logging, mining, road construction, agriculture, and urban/suburban development. This increase in erosion rates has resulted in (1) increased sediment accumulation in small and/or closed catchments, (2) rapid sediment infilling in reservoirs, and (3) shoreline progradation in large embayments such as Chesapeake Bay and San Francisco Bay. Conversely, land use changes and hydrological modifications in valleys and deltas, such as straightening and levee construction along river channels, favor sediment by- pass. The goal of the research described here is to better understand the composition and fate of sediment eroded from mountainous coastal watersheds, and to specifically put current and recent rates of sediment deposition into a longer-term context. Sediment cores collected from wetlands along the Salinas River, a mid-sized mountainous coastal watershed located in central California, have been analyzed for sediment composition, pollen, and rates of accumulation using radiocarbon, Cs-137, Pb-210, and pollen dating methods. The results of this study show current high rates of sediment accumulation in a high relief portion of the watershed, and lower than background rates of sediment accumulation in the deltaic portion of the watershed.

  10. Controls on Surface Water Chemistry in the Upper Merced River Basin, Yosemite National Park, California

    Science.gov (United States)

    Clow, David W.; Alisa Mast, M.; Campbell, Donald H.

    1996-05-01

    Surface water draining granitic bedrock in Yosemite National Park exhibits considerable variability in chemical composition, despite the relative homogeneity of bedrock chemistry. Other geological factors, including the jointing and distribution of glacial till, appear to exert strong controls on water composition. Chemical data from three surface water surveys in the upper Merced River basin conducted in August 1981, June 1988 and August 1991 were analysed and compared with mapped geological, hydrological and topographic features to identify the solute sources and processes that control water chemistry within the basin during baseflow. Water at most of the sampling sites was dilute, with alkalinities ranging from 26 to 77 equiv. l-1. Alkalinity was much higher in two subcatchments, however, ranging from 51 to 302 equiv. l-1. Base cations and silica were also significantly higher in these two catchments than in the rest of the watershed. Concentrations of weathering products in surface water were correlated to the fraction of each subcatchment underlain by surficial material, which is mostly glacial till. Silicate mineral weathering is the dominant control on concentrations of alkalinity, silica and base cations, and ratios of these constituents in surface water reflect the composition of local bedrock. Chloride concentrations in surface water samples varied widely, ranging from <1 to 96 equiv. l-1. The annual volume-weighted mean chloride concentration in the Merced River at the Happy Isles gauge from 1968 to 1990 was 26 equiv. l-1, which was five times higher than in atmospheric deposition (4-5 equiv. l-1), suggesting that a source of chloride exists within the watershed. Saline groundwater springs, whose locations are probably controlled by vertical jointing in the bedrock, are the most likely source of the chloride. Sulphate concentrations varied much less than most other solutes, ranging from 3 to 14 equiv. l-1. Concentrations of sulphate in quarterly samples

  11. Analysis of the Carmel Valley alluvial ground-water basin, Monterey County, California

    Science.gov (United States)

    Kapple, Glenn W.; Mitten, Hugh T.; Durbin, Timothy J.; Johnson, Michael J.

    1984-01-01

    A two-dimensional, finite-element, digital model was developed for the Carmel Valley alluvial ground-water basin using measured, computed, and estimated discharge and recharge data for the basin. Discharge data included evapotranspiration by phreatophytes and agricultural, municipal, and domestic pumpage. Recharge data included river leakage, tributary runoff, and pumping return flow. Recharge from subsurface boundary flow and rainfall infiltration was assumed to be insignificant. From 1974 through 1978, the annual pumping rate ranged from 5,900 to 9,100 acre-feet per year with 55 percent allotted to municipal use principally exported out of the valley, 44 percent to agricultural use, and 1 percent to domestic use. The pumpage return flow within the valley ranged from 900 to 1,500 acre-feet per year. The aquifer properties of transmissivity (about 5,900 feet squared per day) and of the storage coefficient (0.19) were estimated from an average alluvial thickness of 75 feet and from less well-defined data on specific capacity and grain-size distribution. During calibration the values estimated for hydraulic conductivity and storage coefficient for the lower valley were reduced because of the smaller grain size there. The river characteristics were based on field and laboratory analyses of hydraulic conductivity and on altitude survey data. The model is intended principally for simulation of flow conditions using monthly time steps. Time variations in transmissivity and short-term, highrecharge potential are included in the model. The years 1974 through 1978 (including "pre-" and "post-" drought) were selected because of the extreme fluctuation in water levels between the low levels measured during dry years and the above-normal water levels measured during the preceding and following wet years. Also, during this time more hydrologic information was available. Significantly, computed water levels were generally within a few feet of the measured levels, and computed

  12. California GAMA Special Study: Importance of River Water Recharge to Selected Groundwater Basins

    Energy Technology Data Exchange (ETDEWEB)

    Visser, Ate [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Moran, Jean E. [California State Univ. East Bay (CalState), Hayward, CA (United States); Singleton, Michael J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Esser, Bradley K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-03-21

    River recharge represents 63%, 86% and 46% of modern groundwater in the Mojave Desert, Owens Valley, and San Joaquin Valley, respectively. In pre-modern groundwater, river recharge represents a lower fraction: 36%, 46%, and 24% respectively. The importance of river water recharge in the San Joaquin valley has nearly doubled and is likely the result of a total increase of recharge of 40%, caused by river water irrigation return flows. This emphasizes the importance of recharge of river water via irrigation for renewal of groundwater resources. Mountain front recharge and local precipitation contribute to recharge of desert groundwater basins in part as the result of geological features focusing scarce precipitation promoting infiltration. River water recharges groundwater systems under lower temperatures and with larger water table fluctuations than local precipitation recharge. Surface storage is limited in time and volume, as evidenced by cold river recharge temperatures resulting from fast recharge, compared to the large capacity for subsurface storage. Groundwater banking of seasonal surface water flows therefore appears to be a natural and promising method for increasing the resilience of water supply systems. The distinct isotopic and noble gas signatures of river water recharge, compared to local precipitation recharge, reflecting the source and mechanism of recharge, are valuable constraints for numerical flow models.

  13. Selenium in aquatic biota inhabiting agricultural drains in the Salton Sea Basin, California

    Science.gov (United States)

    Saiki, Michael K.; Martin, Barbara A.; May, Thomas W.

    2012-01-01

    Resource managers are concerned that water conservation practices in irrigated farmlands along the southern border of the Salton Sea, Imperial County, California, could increase selenium concentrations in agricultural drainwater and harm the desert pupfish (Cyprinodon macularius), a federally protected endangered species. As part of a broader attempt to address this concern, we conducted a 3-year investigation to collect baseline information on selenium concentrations in seven agricultural drains inhabited by pupfish. We collected water, sediment, selected aquatic food-chain taxa (particulate organic detritus, filamentous algae, net plankton, and midge [Chironomidae] larvae), and two poeciliid fishes (western mosquitofish Gambusia affinis and sailfin molly Poecilia latipinna) for selenium determinations. The two fish species served as ecological surrogates for pupfish, which we were not permitted to sacrifice. Dissolved selenium ranged from 0.70 to 32.8 μg/L, with selenate as the major constituent. Total selenium concentrations in other environmental matrices varied widely among drains, with one drain (Trifolium 18) exhibiting especially high concentrations in detritus, 5.98–58.0 μg Se/g; midge larvae, 12.7–50.6 μg Se/g; mosquitofish, 13.2–20.2 μg Se/g; and mollies, 12.8–30.4 μg Se/g (all tissue concentrations are based on dry weights). Although toxic thresholds for selenium in fishes from the Salton Sea are still poorly understood, available evidence suggests that ambient concentrations of this element may not be sufficiently elevated to adversely affect reproductive success and survival in selenium-tolerant poeciliids and pupfish.

  14. Architecture of a low-angle normal fault zone, southern Basin and Range (SE California)

    Science.gov (United States)

    Goyette, J. A.; John, B. E.; Campbell-Stone, E.; Stunitz, H.; Heilbronner, R.; Pec, M.

    2009-12-01

    Exposures of the denuded Cenozoic detachment fault system in the southern Sacramento Mountains (SE California) delimit the architecture of a regional low-angle normal fault, and highlight the evolution of these enigmatic faults. The fault was initiated ~23 Ma in quartzo-feldspathic basement gneiss and granitoids at a low-angle (2km, and amplitudes up to 100m. These corrugations are continuous along their hinges for up to 3.6 km. Damage zone fracture intensity varies both laterally, and perpendicular to the fault plane (over an area of 25km2), decreasing with depth in the footwall, and varies as a function of lithology and proximity to corrugation walls. Deformation is concentrated into narrow damage zones (100m) are found in areas where low-fracture intensity horses are corralled by sub-horizontal zones of cataclasite (up to 8m) and thick zones of epidote (up to 20cm) and silica-rich alteration (up to 1m). Sub-vertical shear and extension fractures, and sub-horizontal shear fractures/zones dominate the NE side of the core complex. In all cases, sub-vertical fractures verge into or are truncated by low-angle fractures that dominate the top of the damage zone. These low-angle fractures have an antithetic dip to the detachment fault plane. Some sub-vertical fractures become curviplanar close to the fault, where they are folded into parallelism with the sub-horizontal fault surface in the direction of transport. These field data, corroborated by ongoing microstructural analyses, indicate fault activity at a low angle accommodated by a variety of deformation mechanisms dependent on lithology, timing, fluid flow, and fault morphology.

  15. Near-vertical seismic reflection image using a novel acquisition technique across the Vrancea Zone and Foscani Basin, south-eastern Carpathians (Romania).

    NARCIS (Netherlands)

    Panea, I; Stephenson, R.A.; Knapp, C.; Mocanu, V.I.; Drijkoningen, G.; Matenco, L.C.; Knapp, J.; Prodehl, K.

    2005-01-01

    The DACIA PLAN (Danube and Carpathian Integrated Action on Process in the Lithosphere and Neotectonics) deep seismic sounding survey was performed in August-September 2001 in south-eastern Romania, at the same time as the regional deep refraction seismic survey VRANCEA 2001. The main goal of the

  16. Quantifying quagga mussel veliger abundance and distribution in Copper Basin Reservoir (California) using acoustic backscatter.

    Science.gov (United States)

    Anderson, Michael A; Taylor, William D

    2011-11-01

    Quagga mussels (Dreissena bugensis) have been linked to oligotrophication of lakes, alteration of aquatic food webs, and fouling of infrastructure associated with water supply and power generation, causing potentially billions of dollars in direct and indirect damages. Understanding their abundance and distribution is key in slowing their advance, assessing their potential impacts, and evaluating effectiveness of control strategies. Volume backscatter strength (Sv) measurements at 201- and 430-kHz were compared with quagga mussel veliger and zooplankton abundances determined from samples collected using a Wisconsin closing net from the Copper Basin Reservoir on the Colorado River Aqueduct. The plankton within the lower portion of the water column (>18 m depth) was strongly dominated by D-shaped quagga mussel veligers, comprising up to 95-99% of the community, and allowed direct empirical measurement of their mean backscattering cross-section. The upper 0-18 m of the water column contained a smaller relative proportion of veligers based upon net sampling. The difference in mean volume backscatter strength at these two frequencies was found to decrease with decreasing zooplankton abundance (r(2) = 0.94), allowing for correction of Sv due to the contribution of zooplankton and the determination of veliger abundance in the reservoir. Hydroacoustic measurements revealed veligers were often present at high abundances (up to 100-200 ind L(-1)) in a thin 1-2 m layer at the thermocline, with considerable patchiness in their distribution observed along a 700 m transect on the reservoir. Under suitable conditions, hydroacoustic measurements can rapidly provide detailed information on the abundance and distribution of quagga mussel veligers over large areas with high horizontal and vertical resolution. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Vulnerability of Groundwater Recharge to Climate Change in an Alpine Basin (Martis Valley, California)

    Science.gov (United States)

    Visser, A.; Segal, D.; Urióstegui, S. H.; Singleton, M. J.; Moran, J. E.; Esser, B. K.

    2013-12-01

    Martis Valley's groundwater basin is experiencing increasing water demand and changes in the amount and timing of snowmelt due to climate change. Groundwater is the exclusive water supply for the town of Truckee and its surrounding ski resorts and golf courses. The objective of this study was to examine seasonal variability in the aquifer recharge by analyzing supply wells for: 1) tritium and helium isotopes to determine groundwater sources and age, 2) dissolved noble gases to determine recharge temperatures and excess air concentrations and 3) stable isotopes to determine groundwater sources. Recharge temperatures were found to be similar to mean annual air temperatures at lower elevations, suggesting that most recharge is occurring at lower elevations after equilibrating in the vadose zone. Low levels of excess air found in groundwater confirm that most recharge is occurring in the valley alluvium rather than the mountain block. The mean integrated groundwater flow depth was estimated for each well from the temperature difference between recharge and discharge and the geothermal gradient. Groundwater samples contained large amounts of excess terrigenic helium, from both mantle and radiogenic sources. Terrigenic helium and tritium concentrations were used to reconstruct the mixing between the younger and older groundwater sources. Mantle helium originating from the Polaris Fault was used to trace groundwater flow directions. Higher seasonal variability was found in wells with younger groundwater and shallower flow depths, suggesting that changes in the timing and amount of recharge under warmer climate conditions will rather quickly impact at least a portion of the aquifer system in Martis Valley. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  18. High temperature annealing of fission tracks in fluorapatite, Santa Fe Springs oil field, Los Angeles Basin, California

    Science.gov (United States)

    Naeser, Nancy D.; Crowley, Kevin D.; McCulloh, Thane H.; Reaves, Chris M.; ,

    1990-01-01

    Annealing of fission tracks is a kinetic process dependent primarily on temperature and to a laser extent on time. Several kinetic models of apatite annealing have been proposed. The predictive capabilities of these models for long-term geologic annealing have been limited to qualitative or semiquantitative at best, because of uncertainties associated with (1) the extrapolation of laboratory observations to geologic conditions, (2) the thermal histories of field samples, and (3) to some extent, the effect of apatite composition on reported annealing temperatures. Thermal history in the Santa Fe Springs oil field, Los Angeles Basin, California, is constrained by an exceptionally well known burial history and present-day temperature gradient. Sediment burial histories are continuous and tightly constrained from about 9 Ma to present, with an important tie at 3.4 Ma. No surface erosion and virtually no uplift were recorded during or since deposition of these sediments, so the burial history is simple and uniquely defined. Temperature gradient (???40??C km-1) is well established from oil-field operations. Fission-track data from the Santa Fe Springs area should thus provide one critical field test of kinetic annealing models for apatite. Fission-track analysis has been performed on apatites from sandstones of Pliocene to Miocene age from a deep drill hole at Santa Fe Springs. Apatite composition, determined by electron microprobe, is fluorapatite [average composition (F1.78Cl0.01OH0.21)] with very low chlorine content [less than Durango apatite; sample means range from 0.0 to 0.04 Cl atoms, calculated on the basis of 26(O, F, Cl, OH)], suggesting that the apatite is not unusually resistant to annealing. Fission tracks are preserved in these apatites at exceptionally high present-day temperatures. Track loss is not complete until temperatures reach the extreme of 167-178??C (at 3795-4090 m depth). The temperature-time annealing relationships indicated by the new data

  19. Stratigraphy and structural development of the southwest Isla Tiburón marine basin: Implications for latest Miocene tectonic opening and flooding of the northern Gulf of California

    Science.gov (United States)

    Bennett, Scott E. K.; Oskin, Michael; Dorsey, Rebecca; Iriondo, Alexander; Kunk, Michael J.

    2015-01-01

    Accurate information on the timing of earliest marine incursion into the Gulf of California (northwestern México) is critical for paleogeographic models and for understanding the spatial and temporal evolution of strain accommodation across the obliquely divergent Pacific-North America plate boundary. Marine strata exposed on southwest Isla Tiburón (SWIT) have been cited as evidence for a middle Miocene marine incursion into the Gulf of California at least 7 m.y. prior to plate boundary localization ca. 6 Ma. A middle Miocene interpretation for SWIT marine deposits has played a large role in subsequent interpretations of regional tectonics and rift evolution, the ages of marine basins containing similar fossil assemblages along ~1300 km of the plate boundary, and the timing of marine incursion into the Gulf of California. We report new detailed geologic mapping and geochronologic data from the SWIT basin, an elongate sedimentary basin associated with deformation along the dextral-oblique La Cruz fault. We integrate these results with previously published biostratigraphic and geochronologic data to bracket the age of marine deposits in the SWIT basin and show that they have a total maximum thickness of ~300 m. The 6.44 ± 0.05 Ma (Ar/Ar) tuff of Hast Pitzcal is an ash-flow tuff stratigraphically below the oldest marine strata, and the 6.01 ± 0.20 Ma (U/Pb) tuff of Oyster Amphitheater, also an ash-flow tuff, is interbedded with marine conglomerate near the base of the marine section. A dike-fed rhyodacite lava flow that caps all marine strata yields ages of 3.51 ± 0.05 Ma (Ar/Ar) and 4.13 ± 0.09 Ma (U/Pb) from the base of the flow, consistent with previously reported ages of 4.16 ± 1.81 Ma (K-Ar) from the flow top and (K-Ar) 3.7 ± 0.9 Ma from the feeder dike. Our new results confirm a latest Miocene to early Pliocene age for the SWIT marine basin, consistent with previously documented latest Miocene to early Pliocene (ca. 6.2-4.3 Ma) planktonic and benthic

  20. Seismic reflection-based evidence of a transfer zone between the Wagner and Consag basins: implications for defining the structural geometry of the northern Gulf of California

    Science.gov (United States)

    González-Escobar, Mario; Suárez-Vidal, Francisco; Hernández-Pérez, José Antonio; Martín-Barajas, Arturo

    2010-12-01

    This study examines the structural characteristics of the northern Gulf of California by processing and interpreting ca. 415 km of two-dimensional multi-channel seismic reflection lines (data property of Petróleos Mexicanos PEMEX) collected in the vicinity of the border between the Wagner and Consag basins. The two basins appear to be a link between the Delfín Superior Basin to the south, and the Cerro Prieto Basin to the north in the Mexicali-Imperial Valley along the Pacific-North America plate boundary. The seismic data are consistent with existing knowledge of four main structures (master faults) in the region, i.e., the Percebo, Santa María, Consag Sur, and Wagner Sur faults. The Wagner and Consag basins are delimited to the east by the Wagner Sur Fault, and to the west by the Consag Sur Fault. The Percebo Fault borders the western margin of the modern Wagner Basin depocenter, and is oriented N10°W, dipping (on average) ˜40° to the northeast. The trace of the Santa María Fault located in the Wagner Basin strikes N19°W, dipping ˜40° to the west. The Consag Sur Fault is oriented N14°W, and dips ˜42° to the east over a distance of 21 km. To the east of the study area, the Wagner Sur Fault almost parallels the Consag Sur Fault over a distance of ˜86 km, and is oriented N10°W with an average dip of 59° to the east. Moreover, the data provide new evidence that the Wagner Fault is discontinuous between the two basins, and that its structure is more complex than previously reported. A structural high separates the northern Consag Basin from the southern Wagner Basin, comprising several secondary faults oriented NE oblique to the main faults of N-S direction. These could represent a zone of accommodation, or transfer zone, where extension could be transferred from the Wagner to the Consag Basin, or vice versa. This area shows no acoustic basement and/or intrusive body, which is consistent with existing gravimetric and magnetic data for the region.

  1. Pesticides in storm runoff from agricultural and urban areas in the Tuolumne River basin in the vicinity of Modesto, California

    Science.gov (United States)

    Kratzer, Charles R.

    1998-01-01

    The occurrence, concentrations, and loads of dissolved pesticides in storm runoff were compared for two contrasting land uses in the Tuolumne River Basin, California, during two different winter storms: agricultural areas (February 1994) and the Modesto urban area (February 1995). Both storms followed the main application period of pesticides on dormant almond orchards. Eight samples of runoff from agricultural areas were collected from a Tuolumne River site, and 10 samples of runoff from urban areas were collected from five storm drains. All samples were analyzed for 46 pesticides. Six pesticides were detected in runoff from agricultural areas, and 15 pesticides were detected in runoff from urban areas. Chlorpyrifos, diazinon, dacthal (DCPA), metolachlor, and simazine were detected in almost every sample. Median concentrations were higher in the runoff from urban areas for all pesticides except napropamide and simazine. The greater occurrence and concentrations in storm drains is partly attributed to dilution of agricultural runoff by nonstorm base-flow in the Tuolumne River and by storm runoff from nonagricultural and nonurban land. In most cases, the occurrence and relative concentrations of pesticides found in storm runoff from agricultural and urban areas were related to reported pesticide application. Pesticide concentrations in runoff from agricultural areas were more variable during the storm hydrograph than were concentrations in runoff from urban areas. All peak pesticide concentrations in runoff from agricultural areas occurred during the rising limb of the storm hydrograph, whereas peak concentrations in the storm drains occurred at varying times during the storm hydrograph. Transport of pesticides from agricultural areas during the February 1994 storm exceeded transport from urban areas during the February 1995 storm for chlorpyrifos, diazinon, metolachlor, napropamide, and simazine. Transport of DCPA was about the same from agricultural and urban

  2. Relationships among in-situ stress, fractures and faults, and fluid flow: Monterey formation, Santa Maria Basin, California

    Science.gov (United States)

    Finkbeiner, T.; Barton, C.A.; Zoback, M.D.

    1997-01-01

    We used borehole televiewer (BHTV) data from four wells within the onshore and offshore Santa Maria basin, California, to investigate the relationships among fracture distribution, orientation, and variation with depth and in-situ stress. Our analysis of stress-induced well-bore breakouts shows a uniform northeast maximum horizontal stress (SH max) orientation in each well. This direction is consistent with the SH max direction determined from well-bore breakouts in other wells in this region, the northwest trend of active fold axes, and kinematic inversion of nearby earthquake focal plane mechanisms. In contrast to the uniformity of the stress field, fracture orientation, dip, and frequency vary considerably from well to well and within each well. With depth, fractures can be divided into distinct subsets on the basis of fracture frequency and orientation, which correlate with changes of lithology and physical properties. Although factors such as tectonic history, diagenesis, and structural variations obviously have influenced fracture distribution, integration of the in-situ stress and fracture data sets indicates that many of the fractures, faults, and bedding planes are active, small-scale strike-slip and reverse faults in the current northeast-trending transpressive stress field. In fact, we observed local breakout rotations in the wells, providing kinematic evidence for recent shear motion along fracture and bedding-parallel planes. Only in the onshore well do steeply dipping fractures strike parallel to SHmax. Drill-stem tests from two of the offshore wells indicate that formation permeability is greatly enhanced in sections of the wells where fractures are favorably oriented for shear failure in the modern stress field. Thus, relatively small-scale active faults provide important conduits along which fluids migrate.

  3. Status and understanding of groundwater quality in the Madera, Chowchilla Study Unit, 2008: California GAMA Priority Basin Project

    Science.gov (United States)

    Shelton, Jennifer L.; Fram, Miranda S.; Belitz, Kenneth; Jurgens, Bryant C.

    2013-01-01

    Groundwater quality in the approximately 860-square-mile Madera and Chowchilla Subbasins (Madera-Chowchilla study unit) of the San Joaquin Valley Basin was investigated as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study unit is located in California's Central Valley region in parts of Madera, Merced, and Fresno Counties. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory. The Project was designed to provide statistically robust assessments of untreated groundwater quality within the primary aquifer systems in California. The primary aquifer system within each study unit is defined by the depth of the perforated or open intervals of the wells listed in the California Department of Public Health (CDPH) database of wells used for municipal and community drinking-water supply. The quality of groundwater in shallower or deeper water-bearing zones may differ from that in the primary aquifer system; shallower groundwater may be more vulnerable to contamination from the surface. The assessments for the Madera-Chowchilla study unit were based on water-quality and ancillary data collected by the USGS from 35 wells during April-May 2008 and water-quality data reported in the CDPH database. Two types of assessments were made: (1) status, assessment of the current quality of the groundwater resource, and (2) understanding, identification of natural factors and human activities affecting groundwater quality. The primary aquifer system is represented by the grid wells, of which 90 percent (%) had depths that ranged from about 200 to 800 feet (ft) below land surface and had depths to the top of perforations that ranged from about 140 to 400 ft below land surface. Relative-concentrations (sample concentrations divided by benchmark concentrations) were used for

  4. California LLW disposal site development update: Ahead of milestone schedule

    International Nuclear Information System (INIS)

    Romano, S.A.; Gaynor, R.K.

    1987-01-01

    US Ecology has been designated by the State of California to locate, develop and operate a low-level radioactive waste disposal facility. In early 1986, the firm identified eighteen desert basins in southeastern California for siting consideration. Three candidate sites were selected for detailed field characterization work in February, 1987. A preferred site for licensing purposes will be identified in early 1988. California is currently ahead of the siting milestone schedule mandated by the Low-Level Radioactive Waste Policy Amendments Act. It is likely that a license application will be filed before the 1990 milestone date. This paper describes the process undertaken by US Ecology to identify three candidates sites for characterization, and the public involvement program supporting this decision. Future activities leading to final site development are also described

  5. A reindeer footprint in a drilling core from the Allerød-Bølling age succession of Lille Slotseng basin, south-eastern Jylland, Denmark

    DEFF Research Database (Denmark)

    Noe-Nygaard, Nanna; Milàn, Jesper; Hede, Mikkel Ulfeldt

    2005-01-01

    of reindeer were recovered from the early Bølling succession dated to 14.200 cal yr BP. The Slotseng lacustrine basin is a kettle hole basin and almost circular with a diameter of 23 m. The over all transgressive late Glacial and regressive Holocene lake sediment succession covers the time period from 16...

  6. Status of groundwater quality in the Upper Santa Ana Watershed, November 2006--March 2007--California GAMA Priority Basin Project

    Science.gov (United States)

    Kent, Robert; Belitz, Kenneth

    2012-01-01

    Groundwater quality in the approximately 1,000-square-mile (2,590-square-kilometer) Upper Santa Ana Watershed (USAW) study unit was investigated as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study unit is located in southern California in Riverside and San Bernardino Counties. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey and the Lawrence Livermore National Laboratory. The GAMA USAW study was designed to provide a spatially unbiased assessment of untreated groundwater quality within the primary aquifer systems in the study unit. The primary aquifer systems (hereinafter, primary aquifers) are defined as the perforation interval of wells listed in the California Department of Public Health (CDPH) database for the USAW study unit. The quality of groundwater in shallower or deeper water-bearing zones may differ from that in the primary aquifers; shallower groundwater may be more vulnerable to surficial contamination. The assessment is based on water-quality and ancillary data collected by the U.S. Geological Survey (USGS) from 90 wells during November 2006 through March 2007, and water-quality data from the CDPH database. The status of the current quality of the groundwater resource was assessed based on data from samples analyzed for volatile organic compounds (VOCs), pesticides, and naturally occurring inorganic constituents, such as major ions and trace elements. The status assessment is intended to characterize the quality of groundwater resources within the primary aquifers of the USAW study unit, not the treated drinking water delivered to consumers by water purveyors. Relative-concentrations (sample concentration divided by the health- or aesthetic-based benchmark concentration) were used for evaluating groundwater quality for those constituents that have Federal or California regulatory or

  7. Carbon and hydrogen isotopic variations of natural gases in the southeast Columbus basin offshore southeastern Trinidad, West Indies - clues to origin and maturity

    International Nuclear Information System (INIS)

    Norville, Giselle A.; Dawe, Richard A.

    2007-01-01

    Natural gas can have two distinct origins, biogenic and thermogenic sources. This paper investigates the types and maturities of natural gas present in the SE Columbus basin, offshore Trinidad. The chemical composition and the isotope ratios of C and H were determined for approximately 100 samples of natural gas from eight areas within the SE Columbus basin. These compositions and isotopic data are interpreted to identify the origins of gas (biogenic, thermogenic) and maturity. The data showed that the gases in the SE Columbus basin are of both biogenic and thermogenic origin with a trend of mainly thermogenic to mixed to biogenic when moving from SW to NE across the basin. This trend suggests differential burial of the source rock. The presence of mixed gas indicates there was migration of gas in the basin resulting in deeper thermogenic gas mixing with shallow biogenic gas

  8. Structure and Stratigraphy of the Rift Basins in the Northern Gulf of California: Results from Analysis of Seismic Reflection and Borehole Data.

    Science.gov (United States)

    Martín, A.; González, M.; Helenes, J.; García, J.; Aragón, M.; Carreño, A.

    2008-12-01

    The northern Gulf of California contains two parallel, north-south trending rift basin systems separated by a basement-high. The interpretation of several exploration wells, and ~4500 km of seismic reflection data from PEMEX (Mexican national oil company) indicate that the tectonically active basins to the west (Wagner- Consag and Upper Delfin basins) may have initiated synchronously with the now abandoned Tiburón- Tepoca-Altar basins to the east in the Sonora margin. In both basin systems the lower sequence (A) is marine mudstone-siltstone, has parallel reflectors and a largely uniform thickness that reaches up to1.5 km, and gradually pinches out toward the lateral margins. This suggests that the unit was deposited prior to their segmentation by transtensional faulting. Marine microfossils from borehole samples from sequence A in the Tiburón and Consag basins indicates middle Miocene (>11.2 Ma) proto-Gulf conditions. Sequence B conformably overlies sequence A, and is characterized by up to 2 km growth strata with a fanning geometry that show a clear genetic relationship to the major transtensional faults that control the segmentation of the two basin systems. Sequence C in the Tiburón and Tepoca basins is comparatively thin (<800 m) and includes several unconformities, but is much less affected by faulting. In contrast, sequence C in the active Wagner, Consag and Upper Delfin basin is a much thicker (up to 2 km) growth sequence with abundant volcanic intrusions. Marked variations in sequence C in the different basin systems clearly demonstrate a major westward shift of deformation and subsidence at this time. The modern depocenter in Wagner-Consag basins is controlled by the Consag and Wagner faults, which trend parallel to the north ~20 km apart, and show opposite normal offset. These two faults merge at an oblique angle (70°-50°, respectively) into the Cerro Prieto transform fault to the north and likely accommodate an important amount of dextral shear. To

  9. Evolution of the Rodgers Creek–Maacama right-lateral fault system and associated basins east of the northward-migrating Mendocino Triple Junction, northern California

    Science.gov (United States)

    McLaughlin, Robert J.; Sarna-Wojcicki, Andrei M.; Wagner, David L.; Fleck, Robert J.; Langenheim, V.E.; Jachens, Robert C.; Clahan, Kevin; Allen, James R.

    2012-01-01

    The Rodgers Creek–Maacama fault system in the northern California Coast Ranges (United States) takes up substantial right-lateral motion within the wide transform boundary between the Pacific and North American plates, over a slab window that has opened northward beneath the Coast Ranges. The fault system evolved in several right steps and splays preceded and accompanied by extension, volcanism, and strike-slip basin development. Fault and basin geometries have changed with time, in places with younger basins and faults overprinting older structures. Along-strike and successional changes in fault and basin geometry at the southern end of the fault system probably are adjustments to frequent fault zone reorganizations in response to Mendocino Triple Junction migration and northward transit of a major releasing bend in the northern San Andreas fault. The earliest Rodgers Creek fault zone displacement is interpreted to have occurred ca. 7 Ma along extensional basin-forming faults that splayed northwest from a west-northwest proto-Hayward fault zone, opening a transtensional basin west of Santa Rosa. After ca. 5 Ma, the early transtensional basin was compressed and extensional faults were reactivated as thrusts that uplifted the northeast side of the basin. After ca. 2.78 Ma, the Rodgers Creek fault zone again splayed from the earlier extensional and thrust faults to steeper dipping faults with more north-northwest orientations. In conjunction with the changes in orientation and slip mode, the Rodgers Creek fault zone dextral slip rate increased from ∼2–4 mm/yr 7–3 Ma, to 5–8 mm/yr after 3 Ma. The Maacama fault zone is shown from several data sets to have initiated ca. 3.2 Ma and has slipped right-laterally at ∼5–8 mm/yr since its initiation. The initial Maacama fault zone splayed northeastward from the south end of the Rodgers Creek fault zone, accompanied by the opening of several strike-slip basins, some of which were later uplifted and compressed

  10. Status and understanding of groundwater quality in the Klamath Mountains study unit, 2010: California GAMA Priority Basin Project

    Science.gov (United States)

    Bennett, George Luther; Fram, Miranda S.; Belitz, Kenneth

    2014-01-01

    Groundwater quality in the Klamath Mountains (KLAM) study unit was investigated as part of the Priority Basin Project of the California Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study unit is located in Del Norte, Humboldt, Shasta, Siskiyou, Tehama, and Trinity Counties. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory. The GAMA Priority Basin Project was designed to provide a spatially unbiased, statistically robust assessment of the quality of untreated (raw) groundwater in the primary aquifer system. The assessment is based on water-quality data and explanatory factors for groundwater samples collected in 2010 by the USGS from 39 sites and on water-quality data from the California Department of Public Health (CDPH) water-quality database. The primary aquifer system was defined by the depth intervals of the wells listed in the CDPH water-quality database for the KLAM study unit. The quality of groundwater in the primary aquifer system may be different from that in the shallower or deeper water-bearing zones; shallow groundwater may be more vulnerable to surficial contamination. This study included two types of assessments: (1) a status assessment, which characterized the status of the current quality of the groundwater resource by using data from samples analyzed for volatile organic compounds, pesticides, and naturally occurring inorganic constituents, such as major ions and trace elements, and (2) an understanding assessment, which evaluated the natural and human factors potentially affecting the groundwater quality. The assessments were intended to characterize the quality of groundwater resources in the primary aquifer system of the KLAM study unit, not the quality of treated drinking water delivered to consumers by water purveyors. Relative-concentrations (sample concentrations

  11. Changes in productivity and redox conditions during the Last Glacial Maximum as recorded in high-resolution geochemical records from Alfonso Basin, Gulf of California

    Science.gov (United States)

    Choumiline, K.; Lyons, T. W.; Carriquiry, J. D.; Perez-Cruz, L. L.; Beaufort, L.

    2015-12-01

    The Last Glacial Maximum represents the most recent major sea level low stand in Earth history. Such changes in eustatic sea level impacted the oxygenation of marine basins, yet the characteristics and mechanisms of those impacts remain poorly known. Specific basin conditions are needed to develop, record, and preserve those paleoredox changes through time most effectively, including rapid sedimentation rates and silled basin morphologies. The anoxic Alfonso Basin, partially separated from the Gulf of California by a bathymetric sill, is such a place. The basin is located in a dry semiarid region dominated by dust inputs and only occasional tropical cyclone-induced fluvial contributions. We present the first multi-proxy reconstruction of southern Gulf of California paleoredox that covers an uninterrupted timespan from the Late Pleistocene to the present, with an emphasis on the Last Glacial Maximum. In this research we contrast geochemical data from a 47-meter-long sediment core (collected with the giant CALYPSO corer aboard the R/V Marion Dufresne) with the solid phase and pore water chemical data from a shorter but very detailed box core (collected on the R/V El Puma), both from Alfonso Basin. Our results show that during the Late Pleistocene and throughout the Holocene several paleoredox shifts occurred, often accompanied by differences in lamination (laminated/massive alternations) and trace element (Mo, V, U) compositions; detailed Fe chemistry (FeHR/FeTand Fe/Al ratios); as well as carbon and sulfur concentrations and isotope ratios. For example, FeHR/FeT ratios indicate values of roughly 0.15 during the Last Glacial Maximum (lower than theoretic threshold of 0.2 between oxic and anoxic), suggesting more oxic conditions, in comparison to 0.25 and higher in the Holocene. Most of the variability seen in these proxies is related to global sea level change, while some variability is instead related to local variations in paleoproductivity, often connected to

  12. Geochemistry of mercury and other constituents in subsurface sediment—Analyses from 2011 and 2012 coring campaigns, Cache Creek Settling Basin, Yolo County, California

    Science.gov (United States)

    Arias, Michelle R.; Alpers, Charles N.; Marvin-DiPasquale, Mark C.; Fuller, Christopher C.; Agee, Jennifer L.; Sneed, Michelle; Morita, Andrew Y.; Salas, Antonia

    2017-10-31

    Cache Creek Settling Basin was constructed in 1937 to trap sediment from Cache Creek before delivery to the Yolo Bypass, a flood conveyance for the Sacramento River system that is tributary to the Sacramento–San Joaquin Delta. Sediment management options being considered by stakeholders in the Cache Creek Settling Basin include sediment excavation; however, that could expose sediments containing elevated mercury concentrations from historical mercury mining in the watershed. In cooperation with the California Department of Water Resources, the U.S. Geological Survey undertook sediment coring campaigns in 2011–12 (1) to describe lateral and vertical distributions of mercury concentrations in deposits of sediment in the Cache Creek Settling Basin and (2) to improve constraint of estimates of the rate of sediment deposition in the basin.Sediment cores were collected in the Cache Creek Settling Basin, Yolo County, California, during October 2011 at 10 locations and during August 2012 at 5 other locations. Total core depths ranged from approximately 4.6 to 13.7 meters (15 to 45 feet), with penetration to about 9.1 meters (30 feet) at most locations. Unsplit cores were logged for two geophysical parameters (gamma bulk density and magnetic susceptibility); then, selected cores were split lengthwise. One half of each core was then photographed and archived, and the other half was subsampled. Initial subsamples from the cores (20-centimeter composite samples from five predetermined depths in each profile) were analyzed for total mercury, methylmercury, total reduced sulfur, iron speciation, organic content (as the percentage of weight loss on ignition), and grain-size distribution. Detailed follow-up subsampling (3-centimeter intervals) was done at six locations along an east-west transect in the southern part of the Cache Creek Settling Basin and at one location in the northern part of the basin for analyses of total mercury; organic content; and cesium-137, which was

  13. Fish, tributaries of middle Rio Mogi Guaçu, upper rio Paraná basin, São Paulo state, Southeastern Brazil

    OpenAIRE

    Oliveira, A. K.; Apone, F.; Birindelli, J. L. O.; Perez Jr, O. R.

    2009-01-01

    In this paper we compiled a fish list obtained from field collections performed between 1999 and 2005 in four tributaries of the Rio Mogi Guaçu, upper Rio Paraná basin, São Paulo State, Brazil. The collected fishes belong to six orders, 21 families, 60 genera and 82 species. The number of species represents 20 to 30% of the fish richness for the entire upper Rio Paraná basin according to recent estimates. A comparison to earlier published fish lists of the Rio Mogi Guaçu basin, chiefly from i...

  14. Fish, tributaries of middle Rio Mogi Guaçu, upper rio Paraná basin, São Paulo state, Southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Oliveira, A. K.

    2009-01-01

    Full Text Available In this paper we compiled a fish list obtained from field collections performed between 1999 and 2005 infour tributaries of the Rio Mogi Guaçu, upper Rio Paraná basin, São Paulo State, Brazil. The collected fishes belong tosix orders, 21 families, 60 genera and 82 species. The number of species represents 20 to 30% of the fish richness forthe entire upper Rio Paraná basin according to recent estimates. A comparison to earlier published fish lists of the RioMogi Guaçu basin, chiefly from its main river channel, is also presented.

  15. Diferentiation of Basements Types Using Seismic Reflection Data and 40Ar-39Ar Dating in the Western Half of the Farallon Basin (gulf of California, Mexico)

    Science.gov (United States)

    Piñero Lajas, D.; González Fernández, A.; López-Martínez, M.; Lonsdale, P.; Kluesner, J.

    2009-04-01

    The Gulf of California is an active continental rift with an oblique right lateral displacement. Defining a clear boundary between continental and oceanic crust is difficult due to the high sedimentation rate. The new crust is a mixture of sills and sediments that do not produce aligned magnetic anomalies. The main objective of this work is to identify this boundary in the western part of the Farallon Basin. In order to accomplish this goal we used multichannel 2D high-resolution seismic reflection data taken during a cruise aboard oceanographic vessel Francisco de Ulloa in 2006. We also used petrological characterization and 40Ar-39Ar dating of continental samples collected in nearby Santa Catalina, Santa Cruz and San Diego islands, Punta Botella in the Baja California Peninsula, and marine samples of the continental margin next to Las Animas island (ROCA 2008 cruise). Oceanic crust created in the Farallòn spreading axis is identified primarily by saucer-shaped structures in the seismic profiles, which are interpreted as sills. The plutonic continental basement is located on the westernmost part of the margin and is recognized by a continuous high amplitude reflector. There are also volcanic patches in this area, like the South Farallon Massif, which are evident as discontinuities in the high amplitude reflector and with a different seismic character. The Farallon Basin is affected by two different tectonic regimes, the first (compressive) is related to the subduction of the Farallon Plate under the North American Plate, when the plutonic basement was originated. It consists of granodiorites and tonalites belonging to two phases of subduction during the Upper Cretaceous and Early Miocene. Outcrops of the latter phase are exposed in the peninsula of Baja California (Conception Bay); Mexico mainland (middle Sinaloa); and dredged samples of Pescadero Basin. These are similar to the plutonic Santa Catalina Island outcrop described and dated in this study. These

  16. Regional Water Table (1998) and Ground-Water-Level Changes in the Mojave River, and the Morongo Ground-Water Basins, San Bernardino County, California

    Science.gov (United States)

    Smith, Gregory A.; Pimentel, M. Isabel

    2000-01-01

    The Mojave River and the Morongo ground-water basins are in the southwestern part of the Mojave Desert in southern California. Ground water from these basins supplies a major part of the water requirements for the region. The rapid and continuous population growth in this area has resulted in ever-increasing demands on local ground-water resources. The continuing collection and interpretation of ground-water data helps local water districts, military bases, and private citizens gain a better understanding of the ground-water systems and, consequently, water availability. During 1998 the U.S. Geological Survey and other agencies made approximately 2,370 water-level measurements in the Mojave River and the Morongo ground-water basins. These data document recent conditions and changes in ground-water levels. A water-level contour map was drawn using data from 450 wells, providing coverage for most of both basins. Twenty-three hydrographs show long-term (as much as 70 years) water-level trends throughout the basins. To help show effects of late seasonal recharge along the Mojave River, 14 short-term (13 years) hydrographs were created. A water-level change map was compiled to enable comparison of 1996 and 1998 water levels. The Mojave River and the Morongo ground-water basins had little change in water levels between 1996 and 1998 - with the exception of the areas of the Yucca Valley affected by artificial recharge. Other water-level changes were localized and reflected pumping or measurements made before seasonal recharge. Three areas of perched ground water were identified: El Mirage Lake (dry), Adelanto, and Lucerne Valley.

  17. Studies of geology and hydrology in the Basin and Range province, southwestern United States, for isolation of high-level radioactive waste: characterization of the Sonoran region, California

    International Nuclear Information System (INIS)

    Bedinger, M.S.; Sargent, Kenneth A.; Langer, William H.

    1989-01-01

    The Sonoran region of California lies west of the Colorado River and adjoins the Mojave Desert on the west, Death Valley on the northwest, and the Salton trough on the south. The region is arid with annual precipitation ranging from less than 80 millimeters to as great as 250 millimeters in one mountain range; annual free-surface evaporation is as great as 2,500 millimeters. The characteristic basin and range topography of the region was caused by a mid-Tertiary period of intense crustal extension, accompanied by volcanic eruptions, clastic sedimentation, faulting, and tilting. Potential host media for isolation of high-level radioactive waste include granite and other coarsegrained plutonic rocks, ash-flow tuff, and basalt and basaltic andesite lava flows. Thick sections of the unsaturated zone in basin fill, intrusive, and volcanic rocks appear to have potential as host media. The region is bordered on the west by areas of relatively greater Quaternary faulting, vertical crustal uplift, and seismicity. The region has a few areas of Quaternary volcanic activity. Geothermal heat flows of 2.5 heat-flow units or greater and one earthquake of magnitude 6-7 have been recorded. The region includes topographically closed basins as well as basins that drain to the Colorado River. Dry lakes and playas occupy the closed basins. Ground-water recharge and surface runoff are small because of the small amount of precipitation and great potential evaporation. Natural ground-water discharge is by evaporation in the basin playas and by underflow to the Colorado River. Dissolved-solids concentration of ground water generally is less than 500 milligrams per liter, and much of it is of the sodium bicarbonate type. Ground water is saline in many of the playas, and chloride or sulfate is the predominant anion. Small tonnages of ore have been produced from numerous precious and fewer base-metal deposits. (author)

  18. Phylogeography of Beck's Desert Scorpion, Paruroctonus becki, reveals Pliocene diversification in the Eastern California Shear Zone and postglacial expansion in the Great Basin Desert.

    Science.gov (United States)

    Graham, Matthew R; Jaeger, Jef R; Prendini, Lorenzo; Riddle, Brett R

    2013-12-01

    The distribution of Beck's Desert Scorpion, Paruroctonus becki (Gertsch and Allred, 1965), spans the 'warm' Mojave Desert and the western portion of the 'cold' Great Basin Desert. We used genetic analyses and species distribution modeling to test whether P. becki persisted in the Great Basin Desert during the Last Glacial Maximum (LGM), or colonized the area as glacial conditions retreated and the climate warmed. Phylogenetic and network analyses of mitochondrial cytochrome c oxidase 1 (cox1), 16S rDNA, and nuclear internal transcribed spacer (ITS-2) DNA sequences uncovered five geographically-structured groups in P. becki with varying degrees of statistical support. Molecular clock estimates and the geographical arrangement of three of the groups suggested that Pliocene geological events in the tectonically dynamic Eastern California Shear Zone may have driven diversification by vicariance. Diversification was estimated to have continued through the Pleistocene, during which a group endemic to the western Great Basin diverged from a related group in the eastern Mojave Desert and western Colorado Plateau. Demographic and network analyses suggested that P. becki underwent a recent expansion in the Great Basin. According to a landscape interpolation of genetic distances, this expansion appears to have occurred from the northwest, implying that P. becki may have persisted in part of the Great Basin during the LGM. This prediction is supported by species distribution models which suggest that climate was unsuitable throughout most of the Great Basin during the LGM, but that small patches of suitable climate may have remained in areas of the Lahontan Trough. Published by Elsevier Inc.

  19. Trends in nutrient concentrations, loads, and yields in streams in the Sacramento, San Joaquin, and Santa Ana Basins, California, 1975-2004

    Science.gov (United States)

    Kratzer, Charles R.; Kent, Robert; Seleh, Dina K.; Knifong, Donna L.; Dileanis, Peter D.; Orlando, James L.

    2011-01-01

    A comprehensive database was assembled for the Sacramento, San Joaquin, and Santa Ana Basins in California on nutrient concentrations, flows, and point and nonpoint sources of nutrients for 1975-2004. Most of the data on nutrient concentrations (nitrate, ammonia, total nitrogen, orthophosphate, and total phosphorus) were from the U.S. Geological Survey's National Water Information System database (35.2 percent), the California Department of Water Resources (21.9 percent), the University of California at Davis (21.6 percent), and the U.S. Environmental Protection Agency's STOrage and RETrieval database (20.0 percent). Point-source discharges accounted for less than 1 percent of river flows in the Sacramento and San Joaquin Rivers, but accounted for close to 80 percent of the nonstorm flow in the Santa Ana River. Point sources accounted for 4 and 7 percent of the total nitrogen and total phosphorus loads, respectively, in the Sacramento River at Freeport for 1985-2004. Point sources accounted for 8 and 17 percent of the total nitrogen and total phosphorus loads, respectively, in the San Joaquin River near Vernalis for 1985-2004. The volume of wastewater discharged into the Santa Ana River increased almost three-fold over the study period. However, due to improvements in wastewater treatment, the total nitrogen load to the Santa Ana River from point sources in 2004 was approximately the same as in 1975 and the total phosphorus load in 2004 was less than in 1975. Nonpoint sources of nutrients estimated in this study included atmospheric deposition, fertilizer application, manure production, and tile drainage. The estimated dry deposition of nitrogen exceeded wet deposition in the Sacramento and San Joaquin Valleys and in the basin area of the Santa Ana Basin, with ratios of dry to wet deposition of 1.7, 2.8, and 9.8, respectively. Fertilizer application increased appreciably from 1987 to 2004 in all three California basins, although manure production increased in the

  20. Ground-water-quality assessment of the Carson River basin, Nevada and California; analysis of available water-quality data through 1987

    Science.gov (United States)

    Welch, A.H.; Plume, R.W.; Frick, E.A.; Hughes, J.L.

    1989-01-01

    Data on groundwater quality, hydrogeology, and land and water use for the Carson River basin, Nevada and California were analyzed as part of the U. S. Geological Survey National Water-Quality Assessment program. The basin consists of six hydrographic areas--a mountainous headwaters area and five downstream areas interconnected by the Carson River. Each valley contains one or more basin-fill aquifers. The data on groundwater quality came from several agencies and were screened to verify site location and to avoid analyses of treated water. The screened data are stored in the U. S. Geological Survey National Water Information System data base. Differences in sample-collection and preservation procedures among some of the data-collection agencies restrict use of the data to a descriptive analysis. Drinking water standards were employed as the basis for evaluating reported concentrations. Frequencies with which primary or secondary standards are exceeded increase from upstream parts of the basin to downstream parts. Primary standards commonly exceeded are fluoride in upstream areas and arsenic and fluoride in downstream areas. Secondary standards commonly exceeded are iron and manganese in upstream areas and chloride, dissolved solids, iron, manganese, and sulfate in downstream areas. The poorer-quality groundwater generally is a result of natural geochemical reactions, rather than the introduction of chemicals by man. Limited data indicate, however , that manmade organic compounds are present, mostly at or near urban land. (USGS)

  1. Status and understanding of groundwater quality in the Santa Clara River Valley, 2007-California GAMA Priority Basin Project

    Science.gov (United States)

    Burton, Carmen A.; Montrella, Joseph; Landon, Matthew K.; Belitz, Kenneth

    2011-01-01

    Groundwater quality in the approximately 460-square-mile Santa Clara River Valley study unit was investigated from April through June 2007 as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project is conducted by the U.S. Geological Survey (USGS) in collaboration with the California State Water Resources Control Board and the Lawrence Livermore National Laboratory. The Santa Clara River Valley study unit contains eight groundwater basins located in Ventura and Los Angeles Counties and is within the Transverse and Selected Peninsular Ranges hydrogeologic province. The Santa Clara River Valley study unit was designed to provide a spatially unbiased assessment of the quality of untreated (raw) groundwater in the primary aquifer system. The assessment is based on water-quality and ancillary data collected in 2007 by the USGS from 42 wells on a spatially distributed grid, and on water-quality data from the California Department of Public Health (CDPH) database. The primary aquifer system was defined as that part of the aquifer system corresponding to the perforation intervals of wells listed in the CDPH database for the Santa Clara River Valley study unit. The quality of groundwater in the primary aquifer system may differ from that in shallow or deep water-bearing zones; for example, shallow groundwater may be more vulnerable to surficial contamination. Eleven additional wells were sampled by the USGS to improve understanding of factors affecting water quality.The status assessment of the quality of the groundwater used data from samples analyzed for anthropogenic constituents, such as volatile organic compounds (VOCs) and pesticides, as well as naturally occurring inorganic constituents, such as major ions and trace elements. The status assessment is intended to characterize the quality of untreated groundwater resources in the primary aquifers of the Santa Clara River Valley study unit

  2. Riverine Nutrient Trends in the Sacramento and San Joaquin Basins, California: A Comparison to State and Regional Water Quality Policies

    Directory of Open Access Journals (Sweden)

    Brandon Schlegel

    2015-12-01

    Full Text Available doi: http://dx.doi.org/1015447/sfews.2015v13iss4art2Non-point source (NPS contaminant control strategies were initiated in California in the late 1980s under the authority of the State Porter–Cologne Act and eventually for the development of total maximum daily load (TMDL plans, under the federal Clean Water Act. Most of the NPS TMDLs developed for California’s Central Valley (CV region were related to pesticides, but not nutrients. Efforts to reduce pesticide loads and concentrations began in earnest around 1990. The NPS control strategies either encouraged or mandated the use of management practices (MPs. Although TMDLs were largely developed for pesticides, the resultant MPs might have affected the runoff of other potential contaminants (such as nutrients. This study evaluates the effect of agricultural NPS control strategies implemented in California’s CV before and between 1990 and 2013, on nutrients, by comparing trends in surface-water concentrations and loads. In general, use of MPs was encouraged during a “voluntary” period (1990 to 2004 and mandated during an “enforcement” period (2004 to 2013. Nutrient concentrations, loads, and trends were estimated by using a recently developed Weighted Regressions on Time, Discharge, and Season (WRTDS model. Sufficient total phosphorus (TP, total nitrogen (TN, and nitrate (NO3 data were available to compare the voluntary and enforcement periods for twelve sites within the lower Sacramento and San Joaquin basins. Ammonia concentrations and fluxes were evaluated at a subset of these sites. For six of these sites, flow-normalized mean annual concentrations of TP or NO3 decreased at a faster rate during the enforcement period than during the voluntary period. Concentration changes during similar years and ranges of flow conditions suggest that MPs designed for pesticides may also have reduced nutrient loads. Results show that enforceable NPS policies, and accelerated MP implementation

  3. Application of a Process Based Hydrologic Model in a Snow Dominant WaterShed: Upper Feather River Basin in California

    Science.gov (United States)

    Chung, F. I.; Kadir, T.; Galef, J.

    2008-12-01

    Milly et al. in a recent article (Science, Vol319, 1February, 2008, pp573-574) declared that "stationarity is dead." They went on stating, "Finding a suitable successor is crucial for human adaptation to changing climate." California's Department of Water Resources' (DWR's) search for a suitable successor led to the conclusion that a "temperature based approach" might be a good candidate to replace or supplement the traditional "precipitation based" hydrology. In this paper application of a physically based model that begins with ambient air temperature is presented. The projections of precipitation by various GCM's are wide spread and uncertainties on the wetness (or dryness) are abound whereas the future temperature projections, through also wide spread, are unanimous in directional sense-going up or getting warmer over time. Noting this robust nature of the future temperature projections and also noting that the cause of the future precipitation changes is due to the rising temperature, the authors take an approach that the temperature, rather than the precipitation, should be the commencing point in the development of the changing future hydrology. We claim that the main cause of the "death" of the stationarity in a snow dominant high elevation watershed is the warming temperature. Therefore, by commencing with the temperature in the hydrologic process, either the form of precipitation or the melting of the accumulated snow can be captured and the non-stationary future hydrology can be generated for water resources planning and management. The USGS under a contract to DWR completed development of the Precipitation-Runoff Modeling System (PRMS) application for simulating daily streamflow for the Upper Feather River Basin. PRMS simulates all the major snowmelt/precipitation related physical processes including snowpack accumulation/melting, sublimation, evapotranspiration, surface runoff, subsurface flow, and ground water flow. The model was calibrated for Water

  4. Geology, water-quality, hydrology, and geomechanics of the Cuyama Valley groundwater basin, California, 2008--12

    Science.gov (United States)

    Everett, Rhett; Gibbs, Dennis R.; Hanson, Randall T.; Sweetkind, Donald S.; Brandt, Justin T.; Falk, Sarah E.; Harich, Christopher R.

    2013-01-01

    To assess the water resources of the Cuyama Valley groundwater basin in Santa Barbara County, California, a series of cooperative studies were undertaken by the U.S. Geological Survey and the Santa Barbara County Water Agency. Between 2008 and 2012, geologic, water-quality, hydrologic and geomechanical data were collected from selected sites throughout the Cuyama Valley groundwater basin. Geologic data were collected from three multiple-well groundwater monitoring sites and included lithologic descriptions of the drill cuttings, borehole geophysical logs, temperature logs, as well as bulk density and sonic velocity measurements of whole-core samples. Generalized lithologic characterization from the monitoring sites indicated the water-bearing units in the subsurface consist of unconsolidated to partly consolidated sand, gravel, silt, clay, and occasional cobbles within alluvial fan and stream deposits. Analysis of geophysical logs indicated alternating layers of finer- and coarser-grained material that range from less than 1 foot to more than 20 feet thick. On the basis of the geologic data collected, the principal water-bearing units beneath the monitoring-well sites were found to be composed of younger alluvium of Holocene age, older alluvium of Pleistocene age, and the Tertiary-Quaternary Morales Formation. At all three sites, the contact between the recent fill and younger alluvium is approximately 20 feet below land surface. Water-quality samples were collected from 12 monitoring wells, 27 domestic and supply wells, 2 springs, and 4 surface-water sites and were analyzed for a variety of constituents that differed by site, but, in general, included trace elements; nutrients; dissolved organic carbon; major and minor ions; silica; total dissolved solids; alkalinity; total arsenic and iron; arsenic, chromium, and iron species; and isotopic tracers, including the stable isotopes of hydrogen and oxygen, activities of tritium, and carbon-14 abundance. Of the 39

  5. Application of a Nested Modeling Approach Using the Precipitation Runoff Modeling System in the Apalachicola-Chattahoochee-Flint River Basin in the Southeastern USA

    Science.gov (United States)

    Lafontaine, J.; Hay, L.; Viger, R.; Markstrom, S. L.

    2010-12-01

    In order to help environmental resource managers assess potential effects of climate change on ecosystems, the Southeast Regional Assessment Project (SERAP) began in 2009. One component of the SERAP is development and calibration of a set of multi-resolution hydrologic models of the Apalachicola-Chattahoochee-Flint (ACF) River Basin. The ACF River Basin is home to multiple fish and wildlife species of conservation concern, is regionally important for water supply, and has been a recent focus of complementary environmental and climate-change research. Hydrologic models of varying spatial extents and resolutions are required to address varied local to regional water-resource management questions as required by the scope and limits of potential management actions. These models were developed using the U.S. Geological Survey (USGS) Precipitation Runoff Modeling System (PRMS). The coarse-resolution model for the ACF Basin has a contributing area of approximately 19,200 mi2 with the model outlet located at the USGS streamflow gage on the Apalachicola River near Sumatra, Florida. Six fine-resolution PRMS models ranging in size from 153 mi2 to 1,040 mi2 are nested within the coarse-scale model, and have been developed for the following basins: upper Chattahoochee, Chestatee, and Chipola Rivers, Ichawaynochaway, Potato, and Spring Creeks. All of the models simulate basin hydrology using a daily time-step, measured climate data, and basin characteristics such as land cover and topography. Measured streamflow data are used to calibrate and evaluate computed basin hydrology. Land cover projections will be used in conjunction with downscaled Global Climate Model results to project future hydrologic conditions for this set of models.

  6. The Evergreen basin and the role of the Silver Creek fault in the San Andreas fault system, San Francisco Bay region, California

    Science.gov (United States)

    Jachens, Robert C.; Wentworth, Carl M.; Graymer, Russell W.; Williams, Robert; Ponce, David A.; Mankinen, Edward A.; Stephenson, William J.; Langenheim, Victoria

    2017-01-01

    The Evergreen basin is a 40-km-long, 8-km-wide Cenozoic sedimentary basin that lies mostly concealed beneath the northeastern margin of the Santa Clara Valley near the south end of San Francisco Bay (California, USA). The basin is bounded on the northeast by the strike-slip Hayward fault and an approximately parallel subsurface fault that is structurally overlain by a set of west-verging reverse-oblique faults which form the present-day southeastward extension of the Hayward fault. It is bounded on the southwest by the Silver Creek fault, a largely dormant or abandoned fault that splays from the active southern Calaveras fault. We propose that the Evergreen basin formed as a strike-slip pull-apart basin in the right step from the Silver Creek fault to the Hayward fault during a time when the Silver Creek fault served as a segment of the main route by which slip was transferred from the central California San Andreas fault to the Hayward and other East Bay faults. The dimensions and shape of the Evergreen basin, together with palinspastic reconstructions of geologic and geophysical features surrounding it, suggest that during its lifetime, the Silver Creek fault transferred a significant portion of the ∼100 km of total offset accommodated by the Hayward fault, and of the 175 km of total San Andreas system offset thought to have been accommodated by the entire East Bay fault system. As shown previously, at ca. 1.5–2.5 Ma the Hayward-Calaveras connection changed from a right-step, releasing regime to a left-step, restraining regime, with the consequent effective abandonment of the Silver Creek fault. This reorganization was, perhaps, preceded by development of the previously proposed basin-bisecting Mount Misery fault, a fault that directly linked the southern end of the Hayward fault with the southern Calaveras fault during extinction of pull-apart activity. Historic seismicity indicates that slip below a depth of 5 km is mostly transferred from the Calaveras

  7. Routing of terrigenous clastics to oceanic basins in the southern Gulf of California, inherited from features of the pre-spreading protogulf

    Science.gov (United States)

    Lonsdale, P.; Kluesner, J. W.

    2010-12-01

    The southern protogulf was a Miocene belt of continental rupture bounded on the northeast by the Sierra Madre Occidental (SMO) volcanic plateau, and on the southeast by the Main Gulf Escarpment of the Baja California (BC) rift shoulder. Since no later than 8-9Ma, before the depression became a deep inlet of the Pacific, the southern protogulf has hosted the principal shear zone between the Pacific and North American plates. As BC gradually acquired Pacific-plate motion, its vector wrt North America rotated and made the shear zone transtensional, leading to the development of several types of pull-apart basins. Some of them, at right steps between en echelon faults, evolved into the oceanic basins that are now the principal Gulf depocenters. Recent geophysical mapping and geologic sampling in the southern Gulf has clarified the location, structures, and composition of the oceanic/continental crustal boundary, and the mechanisms and routes by which terrigenous clastics reach the intracontinental and oceanic basins.Longitudinal (northwest-southeast) thermohaline and tidal currents transport significant volumes of hemipelagic sediment across the floors of gulf basins, but most of the coarser terrigenous clastics arrive there in density flows, primarily turbidity currents that have built channeled deep-sea fans at the mouths of canyons in the continental slopes. Mapped patterns of submarine canyons, channels and fans confirm that turbidity-current transport has primarily been from the northeast margin, which has permanent mainland rivers with large catchments in the SMO. Most of the arid BC peninsula, with ephemeral-stream drainage directed toward the Pacific, contributes little terrigenous input to the deep-water gulf basins, except in the far south: more than a third of the elevated Cabo Block drains into the gulf, building a large fan on the northwest side of Alarcon Basin. The canyons feeding this fan, cut through crystalline rock and probably subaerial in origin

  8. Digital Elevation Model (DEM) file of topographic elevations for the Death Valley region of southern Nevada and southeastern California processed from US Geological Survey 1-degree Digital Elevation Model data files

    International Nuclear Information System (INIS)

    Turner, A.K.; D'Agnese, F.A.; Faunt, C.C.

    1996-01-01

    Elevation data have been compiled into a digital data base for an ∼100,000-km 2 area of the southern Great Basin, the Death Valley region of southern Nevada, and SE Calif., located between lat 35 degree N, long 115 degree W, and lat 38 degree N, long 118 degree W. This region includes the Nevada Test Site, Yucca Mountain, and adjacent parts of southern Nevada and eastern California and encompasses the Death Valley regional ground-water system. Because digital maps are often useful for applications other than that for which they were originally intended, and because the area corresponds to a region under continuing investigation by several groups, these digital files are being released by USGS

  9. Distinct pathways of redox changes from settling to burial in contrasting marine environments of the Gulf of California: Alfonso, La Paz and Pescadero basins

    Science.gov (United States)

    Choumiline, K.; Lyons, T. W.; Perez-Cruz, L. L.

    2016-02-01

    The oxygenation fluctuations of marine basins are controlled by complex interplay between circulation, climate, productivity and sea level variability, also enhanced by anthropogenic influence. These variations can cause OMZ expansions and increase coastal hypoxia, thus leading to unforeseen consequences of ecosystem alteration, marine life mortality and release of potentially-toxic trace elements previously sequestered within marine sediments. Despite many findings by the scientific community, accurate past reconstructions and future change predictions are far from perfect. This is mainly due to gaps in the understanding of redox processes occurring during settling and burial especially in coastal, yet iron-limited areas of the oceans. Hereby, we tackle this problem by following the transformation pathways of various paleoproductivity and paleoredox indicators (Mo, Ni, V, U, detailed Fe speciation, C and S concentrations and isotope ratios) from their sources to settling and burial. We emphasize sediment trap, core and pore water geochemistry of contrasting oxic, suboxic and anoxic marine settings of the southern Gulf of California: semi-closed Alfonso Basin, OMZ-influenced La Paz Basin and upper-OMZ Pescadero Basin with cyclic dust and fluvial inputs. Our data show evident physicochemical and microbiological transformations during settling with several event-related U enrichments in the marine snow aggregates, probably related to redox microniche processes. The sediment core solid fraction geochemistry, on the other hand, reveals a diagenetic downcore decrease of most highly reactive Fe phases (including the labile ascorbate-extracted Fe), correlating with trace element trends and dissolved Fe in pore waters. The comparison among basins exhibits an expected FeHR/FeT ratio trend for oxic (less than 0.1) and suboxic/anoxic (0.2 and higher) sediments. Although, Mn, S, Mo, U trends varied from core to core suggesting chemical zone and metabolic pathway differences

  10. Effect of irrigation pumpage during drought on karst aquifer systems in highly agricultural watersheds: example of the Apalachicola-Chattahoochee-Flint river basin, southeastern USA

    Science.gov (United States)

    Mitra, Subhasis; Srivastava, Puneet; Singh, Sarmistha

    2016-09-01

    In the Apalachicola-Chattahoochee-Flint (ACF) river basin in Alabama, Georgia, and Florida (USA), population growth in the city of Atlanta and increased groundwater withdrawal for irrigation in southwest Georgia are greatly affecting the supply of freshwater to downstream regions. This study was conducted to understand and quantify the effect of irrigation pumpage on the karst Upper Floridan Aquifer and river-aquifer interactions in the lower ACF river basin in southwest Georgia. The groundwater MODular Finite-Element model (MODFE) was used for this study. The effect of two drought years, a moderate and a severe drought year, were simulated. Comparison of the results of the irrigated and non-irrigated scenarios showed that groundwater discharge to streams is a major outflow from the aquifer, and irrigation can cause as much as 10 % change in river-aquifer flux. The results also show that during months with high irrigation (e.g., June 2011), storage loss (34 %), the recharge and discharge from the upper semi-confining unit (30 %), and the river-aquifer flux (31 %) are the major water components contributing towards the impact of irrigation pumpage in the study area. A similar scenario plays out in many river basins throughout the world, especially in basins in which underlying karst aquifers are directly connected to a nearby stream. The study suggests that improved groundwater withdrawal strategies using climate forecasts needs to be developed in such a way that excessive withdrawals during droughts can be reduced to protect streams and river flows.

  11. Coarse-grained sediment delivery and distribution in the Holocene Santa Monica Basin, California: Implications for evaluating source-to-sink flux at millennial time scales

    Science.gov (United States)

    Romans, B.W.; Normark, W.R.; McGann, M.M.; Covault, J.A.; Graham, S.A.

    2009-01-01

    Utilizing accumulations of coarse-grained terrigenous sediment from deep-marine basins to evaluate the relative contributions of and history of controls on sediment flux through a source-to-sink system has been difficult as a result of limited knowledge of event timing. In this study, six new radiocarbon (14C) dates are integrated with five previously published dates that have been recalibrated from a 12.5-m-thick turbidite section from Ocean Drilling Program (ODP) Site 1015 in Santa Monica Basin, offshore California. This borehole is tied to high-resolution seismic-reflection profiles that cover an 1100 km2 area of the middle and lower Hueneme submarine fan and most of the basin plain. The resulting stratigraphic framework provides the highest temporal resolution for a thick-bedded Holocene turbidite succession to date, permitting an evaluation of source-to-sink controls at millennial (1000 yr) scales. The depositional history from 7 ka to present indicates that the recurrence interval for large turbidity-current events is relatively constant (300-360 yr), but the volume of sediment deposited on the fan and in the basin plain has increased by a factor of 2 over this period. Moreover, the amount of sand per event on the basin plain during the same interval has increased by a factor of 7. Maps of sediment distribution derived from correlation of seismic-reflection profiles indicate that this trend cannot be attributed exclusively to autogenic processes (e.g., progradation of depocenters). The observed variability in sediment accumulation rates is thus largely controlled by allogenic factors, including: (1) increased discharge of Santa Clara River as a result of increased magnitude and frequency of El Ni??o-Southern Oscillation (ENSO) events from ca. 2 ka to present, (2) an apparent change in routing of coarse-grained sediment within the staging area at ca. 3 ka (i.e., from direct river input to indirect, littoral cell input into Hueneme submarine canyon), and (3

  12. Using Drone Imagery and Photogrammetry to Map Basin Stratigraphy and Structures Exposed in Mine, Road, and Arroyo Outcrops, Santa Rosalia, Baja California Sur, Mexico

    Science.gov (United States)

    Banes, A.; Alvarez Ortega, K. G.; Henry, M.; Niemi, T.

    2017-12-01

    During the 2017 Baja Basins Research Experience for Undergraduates (REU), a DJI Phantom 3 Advanced Quadcopter drone equipped with a GPS-enabled, 12 Megapixel camera was manually flown to collect aerial photographs of several geologic outcrops on the Minera Boléo and Lucifer mines in central Baja California Sur. The strip mine faces, roadcuts, and arroyos exposed Neogene to Quaternary sediments of the Santa Rosalía basin including the basal Cu-Zn-Mn-Co-bearing Miocene Boléo Formation that is actively being mined. It is overlain by Plio-Quaternary marine and non-marine deposits. Photographs were collected with a 70% overlap and processed into geographically-referenced, orthophotomosaics using Agisoft Photoscan. The output models have an adequate resolution for viewing bedding and fault characteristics. Measurements can be made inside the 3D models, making drones a useful tool for studying the geometry of stratigraphic, structural, and geomorphologic features. The studied sites included: 1) roadcuts on Mesa Soledad that exposed oblique-slip faults and syntectonically deposited non-marine and marine conglomerates and sandy, fossil-rich Pliocene beach sediment; 2) outcrops of the Boléo Fm in the Texcoco mine area that showed the detailed stratigraphic relationship between ore seams (mantos) and faults; 3) outcrops where sandstone samples were collected for detrital zircon geochronology; 4) strip mine 3120 that exposed faults and folds in the Boléo Formation; and 5) faults in Miocene volcanic rocks in the Arroyo Infierno near the Lucifer mine. This study shows that photogrammetry and modeling of geologic structures exposed in mine and road outcrops can provide useful information for reconstructing basin architecture and clarifying structural evolution of the Santa Rosalia Basin.

  13. Geochemistry of ground water in alluvial basins of Arizona and adjacent parts of Nevada, New Mexico, and California

    Science.gov (United States)

    Robertson, Frederick N.

    1991-01-01

    Chemical and isotope analyses of ground water from 28 basins in the Basin and Range physiographic province of Arizona and parts of adjacent States were used to evaluate ground-water quality, determine processes that control ground-water chemistry, provide independent insight into the hydrologic flow system, and develop information transfer. The area is characterized by north- to northwest-trending mountains separated by alluvial basins that form a regional topography of alternating mountains and valleys. On the basis of ground-water divides or zones of minimal basin interconnection, the area was divided into 72 basins, each representing an individual aquifer system. These systems are joined in a dendritic pattern and collectively constitute the major water resource in the region. Geochemical models were developed to identify reactions and mass transfer responsible for the chemical evolution of the ground water. On the basis of mineralogy and chemistry of the two major rock associations of the area, a felsic model and a mafic model were developed to illustrate geologic, climatic, and physiographic effects on ground-water chemistry. Two distinct hydrochemical processes were identified: (1) reactions of meteoric water with minerals and gases in recharge areas and (2) reactions of ground water as it moves down the hydraulic gradient. Reactions occurring in recharge and downgradient areas can be described by a 13-component system. Major reactions are the dissolution and precipitation of calcite and dolomite, the weathering of feldspars and ferromagnesian minerals, the formation of montmorillonite, iron oxyhydroxides, and probably silica, and, in some basins, ion exchange. The geochemical modeling demonstrated that relatively few phases are required to derive the ground-water chemistry; 14 phases-12 mineral and 2 gas-consistently account for the chemical evolution in each basin. The final phases were selected through analysis of X-ray diffraction and fluorescence data

  14. Regional implications of new chronostratigraphic and paleogeographic data from the Early Permian Darwin Basin, east-central California

    Science.gov (United States)

    Stevens, Calvin H.; Stone, Paul; Magginetti, Robert T.

    2015-01-01

    The Darwin Basin developed in response to episodic subsidence of the western margin of the Cordilleran continental shelf from Late Pennsylvanian (Gzhelian) to Early Permian (late Artinskian) time. Subsidence of the basin was initiated in response to continental truncation farther to the west and was later augmented by thrust emplacement of the Last Chance allochthon. This deep-water basin was filled by voluminous fine-grained siliciclastic turbidites and coarse-grained limestone-gravity-flow deposits. Most of this sediment was derived from the Bird Spring carbonate shelf and cratonal platform to the northeast or east, but some came from an offshore tectonic ridge (Conglomerate Mesa Uplift) to the west that formed at the toe of the Last Chance allochthon. At one point in the late Artinskian the influx of extrabasinal sediment was temporarily cut off, resulting in deposition of a unique black limestone that allows precise correlation throughout the basin. Deep-water sedimentation in the Darwin Basin ended by Kungurian time when complex shallow-water to continental sedimentary facies spread across the region. Major expansion of the Darwin Basin occurred soon after the middle Sakmarian emplacement of the Last Chance allochthon. This tectonic event was approximately coeval with deformation in northeastern Nevada that formed the deep-water Dry Mountain Trough. We herein interpret the two basins to have been structurally continuous. Deposition of the unique black limestone is interpreted to mark a eustatic sea level rise that also can be recognized in Lower Permian sections in east-central Nevada and central Arizona.

  15. Hydrogeochemical and stream-sediment survey (NURE). Preliminary report on the Smoke Creek Desert Basin pilot study (Nevada)

    International Nuclear Information System (INIS)

    1976-01-01

    The Lawrence Livermore Laboratory (LLL) is conducting a hydrogeochemical and stream-sediment survey in the seven western states as part of ERDA's National Uranium Resources Evaluation (NURE) Program. The objective of this survey is to develop a geochemical data base for use by the private sector to locate regions of anomalous uranium content. Prior to wide area coverage, several pilot studies are being undertaken to develop and evaluate sampling and analytical techniques. The second through fifth of these studies were conducted in four playa basins in Nevada, selected to represent different regional geology and uranium occurrence. This study in the Smoke Creek Desert Basin, characterizes igneous surface geology with known uranium occurrences. The Smoke Creek Desert Basin is the largest of the four playa basins and contains an areaof about 2700 square kilometers (1003 square miles). The basin is bordered on the east by the Fox Hills and on the north and east by the Granite Ranges which are characterized by granite, pegmatites, and Tertiary rocks very similar to the lithology of the Winnemucca Basin boundary ranges (study UCID-16911-P-2). On the west the Desert is bordered by an area of extensive basalt flow. There is no known uranium occurrence in the area, and metallization of any kind is scarce. This study is applicable to the western igneous portion of the Basin and Range Province which includes southeastern Oregon, western Nevada, and southeastern California. This report contains only analytical data and sample locations

  16. Interpretation of the Last Chance thrust, Death Valley region, California, as an Early Permian décollement in a previously undeformed shale basin

    Science.gov (United States)

    Stevens, Calvin H.; Stone, Paul

    2005-01-01

    The Last Chance thrust, discontinuously exposed over an area of at least 2500 km2 near the south end of the Cordilleran foreland thrust belt in the Death Valley region of east-central California, is controversial because of its poorly constrained age and its uncertain original geometry and extent. We interpret this thrust to be Early Permian in age, to extend throughout a sedimentary basin in which deep-water Mississippian shale overlain by Pennsylvanian and earliest Permian limestone turbidites accumulated, to represent about 30 km of eastward displacement, and to be related to convergence on a northeast-trending segment of the Early Permian continental margin. Last Chance deformation occurred between the times of the Antler and Sonoma orogenies of Late Devonian–Early Mississippian and Late Permian ages, respectively, and followed Early to Middle Pennsylvanian truncation of the continental margin by transform faulting.

  17. Using (137)Cs measurements to estimate soil erosion rates in the Pčinja and South Morava River Basins, southeastern Serbia.

    Science.gov (United States)

    Petrović, Jelena; Dragović, Snežana; Dragović, Ranko; Đorđević, Milan; Đokić, Mrđan; Zlatković, Bojan; Walling, Desmond

    2016-07-01

    The need for reliable assessments of soil erosion rates in Serbia has directed attention to the potential for using (137)Cs measurements to derive estimates of soil redistribution rates. Since, to date, this approach has not been applied in southeastern Serbia, a reconnaissance study was undertaken to confirm its viability. The need to take account of the occurrence of substantial Chernobyl fallout was seen as a potential problem. Samples for (137)Cs measurement were collected from a zone of uncultivated soils in the watersheds of Pčinja and South Morava Rivers, an area with known high soil erosion rates. Two theoretical conversion models, the profile distribution (PD) model and diffusion and migration (D&M) model were used to derive estimates of soil erosion and deposition rates from the (137)Cs measurements. The estimates of soil redistribution rates derived by using the PD and D&M models were found to differ substantially and this difference was ascribed to the assumptions of the simpler PD model that cause it to overestimate rates of soil loss. The results provided by the D&M model were judged to more reliable. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Airborne Measurements of Ammonia and Implications for Ammonium Nitrate Formation in the Central Valley and the South Coast Air Basin of California

    Science.gov (United States)

    Nowak, J. B.; Neuman, J.; Bahreini, R.; Middlebrook, A. M.; Brock, C. A.; Frost, G. J.; Holloway, J. S.; McKeen, S. A.; Peischl, J.; Pollack, I. B.; Roberts, J. M.; Ryerson, T. B.; Trainer, M.; Parrish, D. D.

    2010-12-01

    Ammonia (NH3) is the dominant gas-phase base in the troposphere. As a consequence, NH3 abundance influences aerosol formation and composition. Ammonium nitrate aerosol is formed from the reaction of gas phase NH3 and nitric acid (HNO3). Anthropogenic emissions of NH3 and NOx (NO + NO2), which in sunlight can be oxidized to form HNO3, can react to form ammonium nitrate aerosol. Agricultural activity (i.e., dairy farms), and urban centers (i.e., Fresno, Los Angeles) are sources of ammonium nitrate gas-phase precursors in both the Central Valley and the South Coast Air Basin. Airborne measurements of NH3, HNO3, particle composition, and particle size distribution were made aboard the NOAA WP-3D research aircraft during May and June 2010 in the Central Valley and the South Coast Air Basin of California, as part of CalNex 2010 (California Research at the Nexus of Air Quality and Climate Change). The highest mixing ratios of NH3, well over 100 parts-per-billion by volume (ppbv), were measured downwind of dairy farms. The high NH3 mixing ratios were highly anti-correlated with HNO3 mixing ratios on fast time scales (~1 s) that correspond to short flight distances (~100 m). During these periods particulate nitrate (NO3-) concentrations increased, indicating ammonium nitrate formation. The meteorological and chemical environments during these periods will be studied to determine the factors driving or limiting ammonium nitrate formation and the resulting regional differences. Finally, the relationship between the NH3 observations and NH3 sources will be examined to assess the emissions and their contribution to ammonium nitrate abundance.

  19. Earthquake clustering inferred from Pliocene Gilbert-type fan deltas in the Loreto basin, Baja California Sur, Mexico

    Science.gov (United States)

    Dorsey, Rebecca J.; Umhoefer, Paul J.; Falk, Peter D.

    1997-08-01

    A stacked sequence of Pliocene Gilbert-type fan deltas in the Loreto basin was shed from the footwall of the dextral-normal Loreto fault and deposited at the margin of a marine basin during rapid fault-controlled subsidence. Fan-delta parasequences coarsen upward from marine siltstone and sandstone at the base, through sandy bottomsets and gravelly foresets, to gravelly nonmarine topsets. Each topset unit is capped by a thin shell bed that records marine flooding of the delta plain. Several mechanisms may have produced repetitive vertical stacking of Gilbert deltas: (1) autocyclic delta-lobe switching; (2) eustatic sea-level fluctuations; (3) climatically controlled fluctuations in sediment input; and (4) episodic subsidence produced by temporal clustering of earthquakes. We favor hypothesis 4 for several reasons, but hypotheses 2 and 3 cannot be rejected at this time. Earthquake clustering can readily produce episodic subsidence at spatial and temporal scales consistent with stratigraphic trends observed in the Loreto basin. This model is supported by comparison with paleoseismological studies that document clustering on active faults over a wide range of time scales. Earthquake clustering is a new concept in basin analysis that may be helpful for understanding repetitive stratigraphy in tectonically active basins.

  20. Macroalgae blooms and δ15N in subtropical coastal lagoons from the Southeastern Gulf of California: Discrimination among agricultural, shrimp farm and sewage effluents

    International Nuclear Information System (INIS)

    Pinon-Gimate, Alejandra; Soto-Jimenez, Martin F.; Ochoa-Izaguirre, Maria Julia; Garcia-Pages, Eynar; Paez-Osuna, Federico

    2009-01-01

    Macroalgae blooms of Gracilaria vermiculophylla, Hypnea spinella and Spyridia filamentosa have been found in coastal lagoons in the SE Gulf of California. Agriculture, livestock, shrimp and poultry farms and sewage contribute anthropogenic nitrogen to the systems. The δ 15 N of these sources, water column and macroalgae were studied in order to identify the N supply for macroalgae blooms. δ 15 N of three species of macroalgae (4.3-13.6 per mille ) were enriched compared to the water column (δ 15 N-NO 3 - 3.7-6.8 per mille ), probably because of fractioning from the macroalgae. δ 15 N of POM (1.4-10.3 per mille ) was similar to the water column but the relationship was unclear. Depending on the site, macroalgae showed different δ 15 N values since some sites receive more or less influence from one given source of the associated watershed, which is reflected in the different δ 15 N values of the macroalgae of the same system and in the relative contributions of the sources.

  1. Micromorphology of Paleosols of the Marília Formation and their Significance in the Paleoenvironmental Evolution of the Bauru Basin, Upper Cretaceous, Southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Márcio Luiz da Silva

    Full Text Available ABSTRACT Deduction of associated paleoenvironments and paleoclimate, definition of the chronosequence of paleosols, and paleogeographic reconstruction have become possible through the application of micromorphology in paleopedology. Micromorphology has also been useful in recognition of weathering processes and definition of minerals formed in succession. In this respect, the objective of this study was to identify the development of pedogenic processes and discuss their significance in the paleoclimate evolution of the Marília Formation (Maastrichtian of Bauru Basin. Three sections of the Marília Formation (A1, A2, and A3 were described, comprising nine profiles. Micromorphologic al analysis was carried out according to the specialized literature. In the Marília Formation, the paleosols developed in sandstones have argillic (Btkm, Bt and carbonate (Bk horizons with different degrees of cementation, forming mainly calcretes. The evolution of pedogenic processes, in light of micromorphological analysis, evidenced three moments or stages for the genesis of paleosols with Bkm, Btk, and Bt horizons, respectively. In the Maastrichtian in the Bauru Basin, the paleosols with Bkm are older and more arid environments, and those with Bt were formed in wetter weather, but not enough to lead to the genesis of enaulic-related distributions, typical of current Oxisols.

  2. Development and application of a groundwater/surface-water flow model using MODFLOW-NWT for the Upper Fox River Basin, southeastern Wisconsin

    Science.gov (United States)

    Feinstein, D.T.; Fienen, M.N.; Kennedy, J.L.; Buchwald, C.A.; Greenwood, M.M.

    2012-01-01

    The Fox River is a 199-mile-long tributary to the Illinois River within the Mississippi River Basin in the states of Wisconsin and Illinois. For the purposes of this study the Upper Fox River Basin is defined as the topographic basin that extends from the upstream boundary of the Fox River Basin to a large wetland complex in south-central Waukesha County called the Vernon Marsh. The objectives for the study are to (1) develop a baseline study of groundwater conditions and groundwater/surface-water interactions in the shallow aquifer system of the Upper Fox River Basin, (2) develop a tool for evaluating possible alternative water-supply options for communities in Waukesha County, and (3) contribute to the methodology of groundwater-flow modeling by applying the recently published U.S. Geological Survey MODFLOW-NWT computer code, (a Newton formulation of MODFLOW-2005 intended for solving difficulties involving drying and rewetting nonlinearities of the unconfined groundwater-flow equation) to overcome computational problems connected with fine-scaled simulation of shallow aquifer systems by means of thin model layers. To simulate groundwater conditions, a MODFLOW grid is constructed with thin layers and small cell dimensions (125 feet per side). This nonlinear unconfined problem incorporates the streamflow/lake (SFR/LAK) packages to represent groundwater/surface-water interactions, which yields an unstable solution sensitive to initial conditions when solved using the Picard-based preconditioned-gradient (PCG2) solver. A particular problem is the presence of many isolated wet water-table cells over dry cells, causing the simulated water table to assume unrealistically high values. Attempts to work around the problem by converting to confined conditions or converting active to inactive cells introduce unacceptable bias. Application of MODFLOW-NWT overcomes numerical problem by smoothing the transition from wet to dry cells and keeps all cells active. The simulation is

  3. Application of the Precipitation-Runoff Modeling System (PRMS) in the Apalachicola-Chattahoochee-Flint River Basin in the southeastern United States

    Science.gov (United States)

    LaFontaine, Jacob H.; Hay, Lauren E.; Viger, Roland J.; Markstrom, Steve L.; Regan, R. Steve; Elliott, Caroline M.; Jones, John W.

    2013-01-01

    A hydrologic model of the Apalachicola–Chattahoochee–Flint River Basin (ACFB) has been developed as part of a U.S. Geological Survey (USGS) National Climate Change and Wildlife Science Center effort to provide integrated science that helps resource managers understand the effect of climate change on a range of ecosystem responses. The hydrologic model was developed as part of the Southeast Regional Assessment Project using the Precipitation Runoff Modeling System (PRMS), a deterministic, distributed-parameter, process-based system that simulates the effects of precipitation, temperature, and land use on basin hydrology. The ACFB PRMS model simulates streamflow throughout the approximately 50,700 square-kilometer basin on a daily time step for the period 1950–99 using gridded climate forcings of air temperature and precipitation, and parameters derived from spatial data layers of altitude, land cover, soils, surficial geology, depression storage (small water bodies), and data from 56 USGS streamgages. Measured streamflow data from 35 of the 56 USGS streamgages were used to calibrate and evaluate simulated basin streamflow; the remaining gage locations were used for model delineation only. The model matched measured daily streamflow at 31 of the 35 calibration gages with Nash-Sutcliffe Model Efficiency Index (NS) greater than 0.6. Streamflow data for some calibration gages were augmented for regulation and water use effects to represent more natural flow volumes. Time-static parameters describing land cover limited the ability of the simulation to match historical runoff in the more developed subbasins. Overall, the PRMS simulation of the ACFB provides a good representation of basin hydrology on annual and monthly time steps. Calibration subbasins were analyzed by separating the 35 subbasins into five classes based on physiography, land use, and stream type (tributary or mainstem). The lowest NS values were rarely below 0.6, whereas the median NS for all five

  4. Reproduction of Pimelodus maculatus(Siluriformes: Pimelodidae in three section of Grande River basin, downstream Porto Colombia dam, south-eastern Brazil

    Directory of Open Access Journals (Sweden)

    Alessandro Loureiro Paschoalini

    Full Text Available The alterations to the hydrologic regime downstream from hydroelectric dams may cause an impact on the reproductive success of fishes. This study aimed to analyse the influence of the physical and chemical parameters of the water of the Grande and Pardo Rivers on gonadal maturation, oocyte diameter, follicular atresia and biological indices of Pimelodus maculatus collected from three river sections: Grande River, downstream from the Porto Colômbia dam (S1, Grande River, downstream from the confluence with the Pardo River (S2 and in the Pardo River channel (S3. Males and females captured in S1 presented significantly higher average values for total length and body weight than those captured in S2 and S3. The gonadosomatic index values were significantly higher in fish collected in S3 and the Fulton condition factor did not show significant differences in fish collected from the three sections. The oocyte diameter, the follicular cells height and the zona pellucida thickness did not show any statistical differences between the sections. Conductivity presented a significant difference between S1 and S3 and during the reproductive period, water transparency presented similar values in the two sampling sections of the Grande River, but a much lower value in the Pardo River. A low frequency of fish with reproductive activity was registered in S1, whereas in S2 and S3 higher frequencies were recorded, emphasising the need of preserving the tributaries for the reproductive success of P. maculatus of the Grande River in south-eastern Brazil.

  5. A basin-scale approach for assessing water resources in a semiarid environment: San Diego region, California and Mexico

    Directory of Open Access Journals (Sweden)

    L. E. Flint

    2012-10-01

    Full Text Available Many basins throughout the world have sparse hydrologic and geologic data, but have increasing demands for water and a commensurate need for integrated understanding of surface and groundwater resources. This paper demonstrates a methodology for using a distributed parameter water-balance model, gaged surface-water flow, and a reconnaissance-level groundwater flow model to develop a first-order water balance. Flow amounts are rounded to the nearest 5 million cubic meters per year.

    The San Diego River basin is 1 of 5 major drainage basins that drain to the San Diego coastal plain, the source of public water supply for the San Diego area. The distributed parameter water-balance model (Basin Characterization Model was run at a monthly timestep for 1940–2009 to determine a median annual total water inflow of 120 million cubic meters per year for the San Diego region. The model was also run specifically for the San Diego River basin for 1982–2009 to provide constraints to model calibration and to evaluate the proportion of inflow that becomes groundwater discharge, resulting in a median annual total water inflow of 50 million cubic meters per year. On the basis of flow records for the San Diego River at Fashion Valley (US Geological Survey gaging station 11023000, when corrected for upper basin reservoir storage and imported water, the total is 30 million cubic meters per year. The difference between these two flow quantities defines the annual groundwater outflow from the San Diego River basin at 20 million cubic meters per year. These three flow components constitute a first-order water budget estimate for the San Diego River basin. The ratio of surface-water outflow and groundwater outflow to total water inflow are 0.6 and 0.4, respectively. Using total water inflow determined using the Basin Characterization Model for the entire San Diego region and the 0.4 partitioning factor, groundwater outflow from the San Diego region, through

  6. Status of groundwater quality in the Borrego Valley, Central Desert, and Low-Use Basins of the Mojave and Sonoran Deserts study unit, 2008-2010: California GAMA Priority Basin Project

    Science.gov (United States)

    Parsons, Mary C.; Hancock, Tracy Connell; Kulongoski, Justin T.; Belitz, Kenneth

    2014-01-01

    Groundwater quality in the approximately 963-square-mile Borrego Valley, Central Desert, and Low-Use Basins of the Mojave and Sonoran Deserts study unit was investigated as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study unit is located in southern California in San Bernardino, Riverside, San Diego, and Imperial Counties. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey and the Lawrence Livermore National Laboratory. The GAMA Borrego Valley, Central Desert, and Low-Use Basins of the Mojave and Sonoran Deserts study was designed to provide a spatially unbiased assessment of the quality of untreated (raw) groundwater in the primary aquifer system. The assessment is based on water-quality and ancillary data collected by the U.S. Geological Survey from 52 wells (49 grid wells and 3 understanding wells) and on water-quality data from the California Department of Public Health database. The primary aquifer system was defined by the depth intervals of the wells listed in the California Department of Public Health database for the Borrego Valley, Central Desert, and Low-Use Basins of the Mojave and Sonoran Deserts study unit. The quality of groundwater in the primary aquifer system may be different from that in the shallower or deeper water-bearing zones; shallow groundwater may be more vulnerable to surficial contamination. This study assesses the status of the current quality of the groundwater resource by using data from samples analyzed for volatile organic compounds (VOCs), pesticides, and naturally occurring inorganic constituents, such as major ions and trace elements. This status assessment is intended to characterize the quality of groundwater resources in the primary aquifer system of the Borrego Valley, Central Desert, and Low-Use Basins of the Mojave and Sonoran Deserts study unit, not the

  7. Ecological distribution of stream macroalgal communities from a drainage basin in the Serra da Canastra National Park, Minas Gerais, Southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Necchi-Júnior O.

    2003-01-01

    Full Text Available Twelve stream segments were sampled four times in 1998-1999 (one sampling per season in the drainage basin of the upper São Francisco River (19º45'-21º25'S, 49º05'-51º30'W, situated in Serra da Canastra National Park, at altitudes ranging from 1,175 to 1,400 m. The macroalgae survey resulted in 30 species, with a predominance of Cyanophyta (12 species = 40% and Chlorophyta (11 species = 36.5% and a lower proportion of Rhodophyta (seven species = 23.5%. Two species, Klebsormidium rivulare (Chlorophyta and Kyliniella latvica (Rhodophyta, were new records for Brazil. Capsosira sp. and Stigonema sp. (Cyanophyta and the "Chantransia" stage of Batrachospermum (Rhodophyta were the most widespread macroalgae, occurring in six sampling sites, whereas 11 species were found at only one site. The proportion of macroalgal morphological types were as follows: mats (33%, free filaments (27%, gelatinous filaments (27%, crusts (7%, tufts (3%, and gelatinous colonies (3%. The flora revealed few species in common (4%-8% with stream macroalgae from other Brazilian regions. The macroalgal communities proved to have species richness values close to the highest values reported in previous studies. The patterns typical for stream macroalgal communities (patchy distribution and dominance of few species were also found in this basin. However, the stream variables most influential in macroalgal distribution in this study (rocky substratum, low pH, high COD, water color, and current velocity were essentially the same that best describe the limnological characteristics of this lotic ecosystem. In addition, this combination of variables differed sharply from results of previous studies in other Brazilian stream ecosystems.

  8. Natural CO2 migrations in the South-Eastern Basin of France: implications for the CO2 storage in sedimentary formations

    International Nuclear Information System (INIS)

    Rubert, Y.

    2009-03-01

    Study of natural CO 2 analogues brings key informations on the factors governing the long term stability/instability of future anthropogenic CO 2 storages. The main objective of this work, through the study of cores from V.Mo.2 well crosscutting the Montmiral natural reservoir (Valence Basin, France), is to trace the deep CO 2 migrations in fractures. Petrographic, geochemical and micro-thermometric studies of the V.Mo.2 cores were thus performed in order: 1) to describe the reservoir filling conditions and 2) to detect possible CO 2 -leakage through the sediments overlying the reservoir. Fluid inclusions from the Paleozoic crystalline basement record the progressive unmixing of a hot homogeneous aquo-carbonic fluid. The Montmiral reservoir was therefore probably fed by a CO 2 -enriched gas component at the Late Cretaceous-Paleogene. The study of the sedimentary column in V.Mo.2 well, demonstrates that the CO 2 did not migrate towards the surface through the thick marly unit (Domerian-Middle Oxfordian). These marls have acted as an impermeable barrier that prevented the upward migration of fluids. Two main stages of fluid circulation have been recognized: 1) an ante- Callovian one related to the Tethysian extension 2) a tertiary stage during which the upper units underwent a karstification, with CO 2 leakage related but which remained confined into the deeper parts of the Valence Basin. Since the Paleogene, the Montmiral reservoir has apparently remained stable, despite the Pyrenean and alpine orogeneses. This is mainly due to the efficient seal formed by the thick marly levels and also to the local structuration in faulted blocks which apparently acted as efficient lateral barriers. (author)

  9. GEOLOGY AND DEPOSITIONAL ENVIRONMENT OF CAMPANO-MAASTRICHTIAN SEDIMENTS IN THE ANAMBRA BASIN, SOUTHEASTERN NIGERIA: EVIDENCE FROM FIELD RELATIONSHIP AND SEDIMENTOLOGICAL STUDY

    Directory of Open Access Journals (Sweden)

    A. E Salufu

    2009-12-01

    Full Text Available The study area lies within the Anambra Basin and it is made up of Enugu Shale, Mamu Formation, Ajali Sandstone, and Nsukka Formation. This study aimed at determining the geology and depositional environmental of these formations through field relationship and grain size distribution morphologic studies.The field data shows Enugu Shale as fissile, light grey with extraformational clast which graded into Mamu Formation whichis made up of shale, coal and sandy shale. It passes upward into Ajali Sandstone which is characterized by cross beds, Herringbonestructures and Ophiomorpha burrows. The youngest formation within the basin is Nsukka Formation.The granulometric study of Mamu Formation shows fine to medium grains, coarse, medium to fine grain for Mamu and Ajali Formation respectively. The standard deviation indicates poorly sorted. The kurtosis shows leptokurtic, platykurtic to very leptokurtic for both while the skewness values indicate positive and symmetrical in all except for Ajali Sandstone that is negatively skewed.The bivariate and the multivariate results reveal shallow marine and fluvial deposits for both Mamu Formation and Ajali Sandstone respectively. The paleocurrent direction of Ajali Sandstone indicates southwest while the provenance is northeast.The fissility of Enugu Shale suggests that it was deposited in low energy environment, distal to proximal lagoon environment.The presence of extraformatonal clast within Enugu Shale indicates fluvial incursion. However, the textural analysis of Mamu Formation suggests a sediment deposited in a low energy environment which favoured deposition of fine to medium size sediments that is, estuary environment. Textural result of Ajali Sandstone in the study area coupled with the field data such as Herring-bone structures, and Ophiomorpha burrows, revealed that Ajali Sandstone was deposited in a tidal environment probably littoral environment. While the light grey colour observed in the

  10. Natural Offshore Oil Seepage and Related Tarball Accumulation on the California Coastline - Santa Barbara Channel and the Southern Santa Maria Basin: Source Identification and Inventory

    Science.gov (United States)

    Lorenson, T.D.; Hostettler, Frances D.; Rosenbauer, Robert J.; Peters, Kenneth E.; Dougherty, Jennifer A.; Kvenvolden, Keith A.; Gutmacher, Christina E.; Wong, Florence L.; Normark, William R.

    2009-01-01

    Oil spillage from natural sources is very common in the waters of southern California. Active oil extraction and shipping is occurring concurrently within the region and it is of great interest to resource managers to be able to distinguish between natural seepage and anthropogenic oil spillage. The major goal of this study was to establish the geologic setting, sources, and ultimate dispersal of natural oil seeps in the offshore southern Santa Maria Basin and Santa Barbara Basins. Our surveys focused on likely areas of hydrocarbon seepage that are known to occur between Point Arguello and Ventura, California. Our approach was to 1) document the locations and geochemically fingerprint natural seep oils or tar; 2) geochemically fingerprint coastal tar residues and potential tar sources in this region, both onshore and offshore; 3) establish chemical correlations between offshore active seeps and coastal residues thus linking seep sources to oil residues; 4) measure the rate of natural seepage of individual seeps and attempt to assess regional natural oil and gas seepage rates; and 5) interpret the petroleum system history for the natural seeps. To document the location of sub-sea oil seeps, we first looked into previous studies within and near our survey area. We measured the concentration of methane gas in the water column in areas of reported seepage and found numerous gas plumes and measured high concentrations of methane in the water column. The result of this work showed that the seeps were widely distributed between Point Conception east to the vicinity of Coal Oil Point, and that they by in large occur within the 3-mile limit of California State waters. Subsequent cruises used sidescan and high resolution seismic to map the seafloor, from just south of Point Arguello, east to near Gaviota, California. The results of the methane survey guided the exploration of the area west of Point Conception east to Gaviota using a combination of seismic instruments. The

  11. Geology and petrology of the Woods Mountains Volcanic Center, southeastern California: Implications for the genesis of peralkaline rhyolite ash flow tuffs

    Science.gov (United States)

    McCurry, Michael

    1988-12-01

    The Woods Mountains Volcanic Center is a middle Miocene silicic caldera complex located at the transition from the northern to the southern Basin and Range provinces of the western United States. It consists of a trachyte-trachydacite-rhyolite-peralkaline rhyolite association of lava flows, domes, plugs, pyroclastic rocks, and epiclastic breccia. Volcanism began at about 16.4 Ma, near the end of a local resurgence of felsic to intermediate magmatism and associated crustal extension. Numerous metaluminous high-K trachyte, trachydacite, and rhyolite lava flows, domes, and pyroclastic deposits accumulated from vents scattered over an area of 200 km2 forming a broad volcanic field with an initial volume of about 10 km3. At 15.8 Ma, about 80 km3 of metaluminous to mildly peralkaline high-K rhyolite ash flows were erupted from vents in the western part of fhe field in three closely spaced pulses, resulting in the formation of a trap door caldera 10 km in diameter. The ash flows formed the Wild Horse Mesa Tuff, a compositionally zoned ash flow sheet that originally covered an area of about 600 km2 to a maximum thickness of at least 320 m. High-K trachyte pumice lapilli, some of which are intimately banded with rhyolite, were produced late in the two later eruptions, Intracaldera volcanism from widely distributed vents rapidly filled the caldera with about 10 km3 of high-K, mildly peralkaline, high-silica rhyolite lava flows and pyroclastic deposits. These are interlayered with breccia derived from the caldera scarp. They are intruded by numerous compositionally similar plugs, some of which structurally uplifted and fractured the center of the caldera. The center evolved above a high-K trachyte magma chamber about 10 km in diameter that had developed and differentiated within the upper crust at about 15.8 Ma. Petrological, geochemical, and geophysical data are consistent with the idea that a cap of peralkaline rhyolite magma formed within the trachyte chamber as a result

  12. Preliminary report on fluid inclusions from halites in the Castile and lower Salado formations of the Delaware Basin, southeastern New Mexico

    International Nuclear Information System (INIS)

    Stein, C.L.

    1985-09-01

    A suite of samples composed primarily of halite from the upper Castile and lower Salado Formations of the Permian Basin was selected from Waste Isolation Pilot Plant (WIPP) core for a reconnaissance study of fluid inclusions. Volume percent of these trapped fluids averaged 0.7% to 1%. Freezing-point depressions varied widely and appeared to be unrelated to fluid-inclusion type, to sedimentary facies, or to stratigraphic depth. However, because very low freezing points were usually associated with anhydrite, a relation may exist between freezing-point data and lithology. Dissolved sulfate values were constant through the Castile, then decreased markedly with lesser depth in the lower Salado. This trend correlates very well with observed mineralogy and is consistent with an interpretation of the occurrence of secondary polyhalite as a result of gypsum or anhydrite alteration with simultaneous consumption of dissolved sulfate from the coexisting fluids. Together with the abundance and distribution of fluid inclusions in primary or ''hopper'' crystal structures, this evidence suggests that inclusions seen in these halites did not migrate any significant geographical distance since their formation. 28 refs., 17 figs., 2 tabs

  13. Bryophyte and pteridophyte spores and other palynomorphs in quaternary marine sediments from Campos Basin, southeastern Brazil: Core BU-91-GL-05

    Directory of Open Access Journals (Sweden)

    Aline Gonçalves de Freitas

    2015-06-01

    Full Text Available This paper presents morphological descriptions and ecological data of cryptogam spores and other non-pollen palynomorphs from Quaternary sediments of Campos Basin, Rio de Janeiro, SE Brazil. The ages were derived from biostratigraphy of planktonic foraminifers and two radiocarbon dates, and suggest that sediment deposition started in the last 140,000 years BP. Thirty different types of palynomorphs were identified, described, and photographed: two bryophyte spores (sensu lato; 21 pteridophyte spores; four freshwater microalgae; onePseudoschizaea; and two microfungi. Some of the identified spores (Sphagnum, Blechnum, Cyatheaceae, Dennstaedtiaceae, Lycopodiella, Microgramma, Polypodium, Acrostichum, Pityrogramma, and Lygodium are related to the modern flora found on the northern coast of Rio de Janeiro State, at the Restinga of Jurubatiba, from vegetation types such as shrub swamp/coastal swamp formation, seasonally flooded forest, Clusia and Ericaceae woods, and disturbed vegetation. The freshwater microalgae and the microfungi are also presently recorded from the coastal lagoons of this region. The high spore concentration in slope sediments reflects the intense terrigenous influx, caused by a relative low sealevel during glacial stages. Palynological analysis suggests the presence of taxa from flooded forests and humid areas in the coastal plain during glacial and interglacial stages of the Late Pleistocene.

  14. Surface-water quality and suspended-sediment quantity and quality within the Big River Basin, southeastern Missouri, 2011-13

    Science.gov (United States)

    Barr, Miya N.

    2016-01-28

    Missouri was the leading producer of lead in the United States—as well as the world—for more than a century. One of the lead sources is known as the Old Lead Belt, located in southeast Missouri. The primary ore mineral in the region is galena, which can be found both in surface deposits and underground as deep as 200 feet. More than 8.5 million tons of lead were produced from the Old Lead Belt before operations ceased in 1972. Although active lead mining has ended, the effects of mining activities still remain in the form of large mine waste piles on the landscape typically near tributaries and the main stem of the Big River, which drains the Old Lead Belt. Six large mine waste piles encompassing more than 2,800 acres, exist within the Big River Basin. These six mine waste piles have been an available source of trace element-rich suspended sediments transported by natural erosional processes downstream into the Big River.

  15. Ground-Water Quality Data in the Monterey Bay and Salinas Valley Basins, California, 2005 - Results from the California GAMA Program

    Science.gov (United States)

    Kulongoski, Justin T.; Belitz, Kenneth

    2007-01-01

    Ground-water quality in the approximately 1,000-square-mile Monterey Bay and Salinas Valley study unit was investigated from July through October 2005 as part of the California Ground-Water Ambient Monitoring and Assessment (GAMA) program. The study was designed to provide a spatially unbiased assessment of raw ground-water quality, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 94 public-supply wells and 3 monitoring wells in Monterey, Santa Cruz, and San Luis Obispo Counties. Ninety-one of the public-supply wells sampled were selected to provide a spatially distributed, randomized monitoring network for statistical representation of the study area. Six wells were sampled to evaluate changes in water chemistry: three wells along a ground-water flow path were sampled to evaluate lateral changes, and three wells at discrete depths from land surface were sampled to evaluate changes in water chemistry with depth from land surface. The ground-water samples were analyzed for volatile organic compounds (VOCs), pesticides, pesticide degradates, nutrients, major and minor ions, trace elements, radioactivity, microbial indicators, and dissolved noble gases (the last in collaboration with Lawrence Livermore National Laboratory). Naturally occurring isotopes (tritium, carbon-14, helium-4, and the isotopic composition of oxygen and hydrogen) also were measured to help identify the source and age of the sampled ground water. In total, 270 constituents and water-quality indicators were investigated for this study. This study did not attempt to evaluate the quality of water delivered to consumers; after withdrawal from the ground, water typically is treated, disinfected, and (or) blended with other waters to maintain water quality. In addition, regulatory thresholds apply to treated water that is served to the consumer, not to raw ground water. In this study, only six constituents, alpha radioactivity, N

  16. Feasibility study of heavy oil recovery in the Permian Basin (Texas and New Mexico)

    International Nuclear Information System (INIS)

    Olsen, D.K.; Johnson, W.I.

    1993-05-01

    This report is one of a series of publications assessing the feasibility of increasing domestic heavy oil production. Each report covers select areas of the United States. The Permian Basin of West Texas and Southeastern New Mexico is made up of the Midland, Delaware, Val Verde, and Kerr Basins; the Northwestern, Eastern, and Southern shelves; the Central Basin Platform, and the Sheffield Channel. The present day Permian Basin was one sedimentary basin until uplift and subsidence occurred during Pennsylvanian and early Permian Age to create the configuration of the basins, shelves, and platform of today. The basin has been a major light oil producing area served by an extensive pipeline network connected to refineries designed to process light sweet and limited sour crude oil. Limited resources of heavy oil (10'' to 20'' API gravity) occurs in both carbonate and sandstone reservoirs of Permian and Cretaceous Age. The largest cumulative heavy oil production comes from fluvial sandstones of the Cretaceous Trinity Group. Permian heavy oil is principally paraffinic and thus commands a higher price than asphaltic California heavy oil. Heavy oil in deeper reservoirs has solution gas and low viscosity and thus can be produced by primary and by waterflooding. Because of the nature of the resource, the Permian Basin should not be considered a major heavy oil producing area

  17. Feasibility study of heavy oil recovery in the Permian Basin (Texas and New Mexico)

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, D.K.; Johnson, W.I.

    1993-05-01

    This report is one of a series of publications assessing the feasibility of increasing domestic heavy oil production. Each report covers select areas of the United States. The Permian Basin of West Texas and Southeastern New Mexico is made up of the Midland, Delaware, Val Verde, and Kerr Basins; the Northwestern, Eastern, and Southern shelves; the Central Basin Platform, and the Sheffield Channel. The present day Permian Basin was one sedimentary basin until uplift and subsidence occurred during Pennsylvanian and early Permian Age to create the configuration of the basins, shelves, and platform of today. The basin has been a major light oil producing area served by an extensive pipeline network connected to refineries designed to process light sweet and limited sour crude oil. Limited resources of heavy oil (10'' to 20'' API gravity) occurs in both carbonate and sandstone reservoirs of Permian and Cretaceous Age. The largest cumulative heavy oil production comes from fluvial sandstones of the Cretaceous Trinity Group. Permian heavy oil is principally paraffinic and thus commands a higher price than asphaltic California heavy oil. Heavy oil in deeper reservoirs has solution gas and low viscosity and thus can be produced by primary and by waterflooding. Because of the nature of the resource, the Permian Basin should not be considered a major heavy oil producing area.

  18. Feasibility study of heavy oil recovery in the Permian Basin (Texas and New Mexico)

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, D.K.; Johnson, W.I.

    1993-05-01

    This report is one of a series of publications assessing the feasibility of increasing domestic heavy oil production. Each report covers select areas of the United States. The Permian Basin of West Texas and Southeastern New Mexico is made up of the Midland, Delaware, Val Verde, and Kerr Basins; the Northwestern, Eastern, and Southern shelves; the Central Basin Platform, and the Sheffield Channel. The present day Permian Basin was one sedimentary basin until uplift and subsidence occurred during Pennsylvanian and early Permian Age to create the configuration of the basins, shelves, and platform of today. The basin has been a major light oil producing area served by an extensive pipeline network connected to refineries designed to process light sweet and limited sour crude oil. Limited resources of heavy oil (10`` to 20`` API gravity) occurs in both carbonate and sandstone reservoirs of Permian and Cretaceous Age. The largest cumulative heavy oil production comes from fluvial sandstones of the Cretaceous Trinity Group. Permian heavy oil is principally paraffinic and thus commands a higher price than asphaltic California heavy oil. Heavy oil in deeper reservoirs has solution gas and low viscosity and thus can be produced by primary and by waterflooding. Because of the nature of the resource, the Permian Basin should not be considered a major heavy oil producing area.

  19. Status of groundwater quality in the Southern, Middle, and Northern Sacramento Valley study units, 2005-08: California GAMA Priority Basin Project

    Science.gov (United States)

    Bennett, George L.; Fram, Miranda S.; Belitz, Kenneth

    2011-01-01

    Groundwater quality in the Southern, Middle, and Northern Sacramento Valley study units was investigated as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study units are located in California's Central Valley and include parts of Butte, Colusa, Glenn, Placer, Sacramento, Shasta, Solano, Sutter, Tehama, Yolo, and Yuba Counties. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey and the Lawrence Livermore National Laboratory. The three study units were designated to provide spatially-unbiased assessments of the quality of untreated groundwater in three parts of the Central Valley hydrogeologic province, as well as to provide a statistically consistent basis for comparing water quality regionally and statewide. Samples were collected in 2005 (Southern Sacramento Valley), 2006 (Middle Sacramento Valley), and 2007-08 (Northern Sacramento Valley). The GAMA studies in the Southern, Middle, and Northern Sacramento Valley were designed to provide statistically robust assessments of the quality of untreated groundwater in the primary aquifer systems that are used for drinking-water supply. The assessments are based on water-quality data collected by the USGS from 235 wells in the three study units in 2005-08, and water-quality data from the California Department of Public Health (CDPH) database. The primary aquifer systems (hereinafter, referred to as primary aquifers) assessed in this study are defined by the depth intervals of the wells in the CDPH database for each study unit. The quality of groundwater in shallow or deep water-bearing zones may differ from quality of groundwater in the primary aquifers; shallow groundwater may be more vulnerable to contamination from the surface. The status of the current quality of the groundwater resource was assessed by using data from samples analyzed for volatile organic

  20. The character and causes of flash flood occurrence changes in mountainous small basins of Southern California under projected climatic change

    Directory of Open Access Journals (Sweden)

    Theresa M. Modrick

    2015-03-01

    Full Text Available Study region: Small watersheds (O[25 km2] in the mountain regions of southern California comprise the study region. Study focus: This paper examines changes in flash flood occurrence in southern California resulting from projected climatic change. The methodology synthesizes elements of meteorological modeling, hydrology and geomorphology into an integrated modeling approach to define flash flood occurrence in a systematic and consistent way on a regional basis with high spatial and temporal resolution appropriate for flash flooding. A single climate model with three-dimensional atmospheric detail was used as input to drive simulations for historical and future periods. New hydrological insights for the region: Results indicate an increase in flash flood occurrence for the study region. For two distributed hydrologic models employed, the increase in flash flood occurrence frequency is on average between 30% and 40%. Regional flash flood occurrence is characterized by near saturation of the upper soil layer, and wider ranges in lower soil layer saturation and in precipitation. Overall, a decrease in the total number of precipitation events was found, although with increased precipitation intensity, increased event duration, and higher soil saturation conditions for the 21st century. This combination could signify more hazardous conditions, with fewer precipitation events but higher rainfall intensity and over soils with higher initial soil moisture saturation, leading to more frequent occurrence of flash floods. Keywords: Flash flooding, Climate change, Soil moisture, Precipitation, Distributed hydrologic modeling

  1. Natural recharge estimation and uncertainty analysis of an adjudicated groundwater basin using a regional-scale flow and subsidence model (Antelope Valley, California, USA)

    Science.gov (United States)

    Siade, Adam J.; Nishikawa, Tracy; Martin, Peter

    2015-01-01

    Groundwater has provided 50–90 % of the total water supply in Antelope Valley, California (USA). The associated groundwater-level declines have led the Los Angeles County Superior Court of California to recently rule that the Antelope Valley groundwater basin is in overdraft, i.e., annual pumpage exceeds annual recharge. Natural recharge consists primarily of mountain-front recharge and is an important component of the total groundwater budget in Antelope Valley. Therefore, natural recharge plays a major role in the Court’s decision. The exact quantity and distribution of natural recharge is uncertain, with total estimates from previous studies ranging from 37 to 200 gigaliters per year (GL/year). In order to better understand the uncertainty associated with natural recharge and to provide a tool for groundwater management, a numerical model of groundwater flow and land subsidence was developed. The transient model was calibrated using PEST with water-level and subsidence data; prior information was incorporated through the use of Tikhonov regularization. The calibrated estimate of natural recharge was 36 GL/year, which is appreciably less than the value used by the court (74 GL/year). The effect of parameter uncertainty on the estimation of natural recharge was addressed using the Null-Space Monte Carlo method. A Pareto trade-off method was also used to portray the reasonableness of larger natural recharge rates. The reasonableness of the 74 GL/year value and the effect of uncertain pumpage rates were also evaluated. The uncertainty analyses indicate that the total natural recharge likely ranges between 34.5 and 54.3 GL/year.

  2. Natural recharge estimation and uncertainty analysis of an adjudicated groundwater basin using a regional-scale flow and subsidence model (Antelope Valley, California, USA)

    Science.gov (United States)

    Siade, Adam; Nishikawa, Tracy; Martin, Peter

    2015-09-01

    Groundwater has provided 50-90 % of the total water supply in Antelope Valley, California (USA). The associated groundwater-level declines have led the Los Angeles County Superior Court of California to recently rule that the Antelope Valley groundwater basin is in overdraft, i.e., annual pumpage exceeds annual recharge. Natural recharge consists primarily of mountain-front recharge and is an important component of the total groundwater budget in Antelope Valley. Therefore, natural recharge plays a major role in the Court's decision. The exact quantity and distribution of natural recharge is uncertain, with total estimates from previous studies ranging from 37 to 200 gigaliters per year (GL/year). In order to better understand the uncertainty associated with natural recharge and to provide a tool for groundwater management, a numerical model of groundwater flow and land subsidence was developed. The transient model was calibrated using PEST with water-level and subsidence data; prior information was incorporated through the use of Tikhonov regularization. The calibrated estimate of natural recharge was 36 GL/year, which is appreciably less than the value used by the court (74 GL/year). The effect of parameter uncertainty on the estimation of natural recharge was addressed using the Null-Space Monte Carlo method. A Pareto trade-off method was also used to portray the reasonableness of larger natural recharge rates. The reasonableness of the 74 GL/year value and the effect of uncertain pumpage rates were also evaluated. The uncertainty analyses indicate that the total natural recharge likely ranges between 34.5 and 54.3 GL/year.

  3. Change in the forested and developed landscape of the Lake Tahoe basin, California and Nevada, USA, 1940-2002

    Science.gov (United States)

    Raumann, C.G.; Cablk, Mary E.

    2008-01-01

    The current ecological state of the Lake Tahoe basin has been shaped by significant landscape-altering human activity and management practices since the mid-1850s; first through widespread timber harvesting from the 1850s to 1920s followed by urban development from the 1950s to the present. Consequences of landscape change, both from development and forest management practices including fire suppression, have prompted rising levels of concern for the ecological integrity of the region. The impacts from these activities include decreased water quality, degraded biotic communities, and increased fire hazard. To establish an understanding of the Lake Tahoe basin's landscape change in the context of forest management and development we mapped, quantified, and described the spatial and temporal distribution and variability of historical changes in land use and land cover in the southern Lake Tahoe basin (279 km2) from 1940 to 2002. Our assessment relied on post-classification change detection of multi-temporal land-use/cover and impervious-surface-area data that were derived through manual interpretation, image processing, and GIS data integration for four dates of imagery: 1940, 1969, 1987, and 2002. The most significant land conversion during the 62-year study period was an increase in developed lands with a corresponding decrease in forests, wetlands, and shrublands. Forest stand densities increased throughout the 62-year study period, and modern thinning efforts resulted in localized stand density decreases in the latter part of the study period. Additionally forests were gained from succession, and towards the end of the study period extensive tree mortality occurred. The highest rates of change occurred between 1940 and 1969, corresponding with dramatic development, then rates declined through 2002 for all observed landscape changes except forest density decrease and tree mortality. Causes of landscape change included regional population growth, tourism demands

  4. Preliminary seismicity and focal mechanisms for the southern Great Basin of Nevada and California: January 1992 through September 1992

    International Nuclear Information System (INIS)

    Harmsen, S.C.

    1994-01-01

    The telemetered southern Great Basin seismic network (SGBSN) is operated for the Department of Energy's Yucca Mountain Project (YMP). The US Geological Survey, Branch of Earthquake and Landslide Hazards, maintained this network until September 30, 1992, at which time all operational and analysis responsibilities were transferred to the University of Nevada at Reno Seismological Laboratory (UNRSL). This report contains preliminary earthquake and chemical explosion hypocenter listings and preliminary earthquake focal mechanism solutions for USGS/SGBSN data for the period January 1, 1992 through September 30, 1992, 15:00 UTC

  5. Preliminary seismicity and focal mechanisms for the southern Great Basin of Nevada and California: January 1992 through September 1992

    Energy Technology Data Exchange (ETDEWEB)

    Harmsen, S.C.

    1994-06-01

    The telemetered southern Great Basin seismic network (SGBSN) is operated for the Department of Energy`s Yucca Mountain Project (YMP). The US Geological Survey, Branch of Earthquake and Landslide Hazards, maintained this network until September 30, 1992, at which time all operational and analysis responsibilities were transferred to the University of Nevada at Reno Seismological Laboratory (UNRSL). This report contains preliminary earthquake and chemical explosion hypocenter listings and preliminary earthquake focal mechanism solutions for USGS/SGBSN data for the period January 1, 1992 through September 30, 1992, 15:00 UTC.

  6. Assessing water source and channel type as factors affecting benthic macroinvertebrate and periphyton assemblages in the highly urbanized Santa Ana River Basin, California

    Science.gov (United States)

    Burton, C.A.; Brown, L.R.; Belitz, K.

    2005-01-01

    The Santa Ana River basin is the largest stream system in Southern California and includes a densely populated coastal area. Extensive urbanization has altered the geomorphology and hydrology of the streams, adversely affecting aquatic communities. We studied macroinvertebrate and periphyton assemblages in relation to two categorical features of the highly engineered hydrologic system-water source and channel type. Four water sources were identified-natural, urban-impacted groundwater, urban runoff, and treated wastewater. Three channel types were identified-natural, channelized with natural bottom, and concrete-lined. Nineteen sites, covering the range of these two categorical features, were sampled in summer 2000. To minimize the effects of different substrate types among sites, artificial substrates were used for assessing macroinvertebrate and periphyton assemblages. Physical and chemical variables and metrics calculated from macroinvertebrate and periphyton assemblage data were compared among water sources and channel types using analysis of variance and multiple comparison tests. Macroinvertebrate metrics exhibiting significant (P water sources included taxa and Ephemeroptera-Plecoptera-Trichoptera richness, relative richness and abundance of nonchironomid dipterans, orthoclads, oligochaetes, and some functional-feeding groups such as parasites and shredders. Periphyton metrics showing significant differences between water sources included blue-green algae biovolume and relative abundance of nitrogen heterotrophic, eutrophic, motile, and pollution-sensitive diatoms. The relative abundance of trichopterans, tanytarsini chironomids, noninsects, and filter feeders, as well as the relative richness and abundance of diatoms, were significantly different between channel types. Most physical variables were related to channel type, whereas chemical variables and some physical variables (e.g., discharge, velocity, and channel width) were related to water source. These

  7. Benthic macrofaunal colonization patterns and preservation of laminated sediments: Observations in an extreme coastal basin environment in the lower Gulf of California

    Science.gov (United States)

    Herguera, J.; Paull, C. K.; Anderson, K.; Gwiazda, R.; Lundsten, E. M.; Kundz, L.; Edwards, B. D.; McGann, M. L.

    2012-12-01

    New observations and cores obtained with the ROV Doc Ricketts operated from the RV/Western Flyer provide a glimpse into a macrofauna barren sea-floor where laminated sediments are known to accumulate on the sea-floor of Alfonso Basin. This basin, located north of La Paz Bay, Baja California, is known to be an important repository of laminated sediments due to a combination of the relatively high input of terrigenous sediments brought in by summer rains, a moderate to high export productivity from its surface waters, and the very low oxygen concentrations at depth bathed by tropical subsurface waters. These laminated sediments are unique repositories of paleoceanographic and paleoclimatic information for its very high resolution records of past conditions comparable to ice core, tree ring, coral and cave records although spanning continuously much further back in time. However, the paleoceanographic community rarely has had the opportunity to visualize the seafloor surface where these sediments are accumulating and examine the biological abundance patterns in these extreme environments. Here we will show results from ROV Doc Ricketts quantitative video transects providing benthic faunal abundance patterns on the seafloor in these highly oxygen depleted bottom waters. These observations are further compared with the underlying stratigraphy. A coring system carried on the ROV allowed us to replicate cores and to collect a transect of 5 closely spaced cores to evaluate the horizontal extent of the observed variability down-core. We will also show some preliminary results from x-radiographs showing the nature of the laminations and its sediment composition based on elemental analysis on organic carbon, carbonate and biogenic opal analysis. New XRF results from a box core will be used to calibrate its terrigenous components with the historical rainfall record and evaluate its potential to reconstruct summer precipitation patterns in this region.

  8. A History of Warming Sea Surface Temperature and Ocean Acidification Recorded by Planktonic Foraminifera Geochemistry from the Santa Barbara Basin, California

    Science.gov (United States)

    Osborne, E.; Thunell, R.; Bizimis, M.; Buckley, W. P., Jr.; benitez-Nelson, C. R.; Chartier, C. J.

    2015-12-01

    The geochemistry of foraminiferal shells has been widely used to reconstruct past conditions of the ocean and climate. Since the onset of the Industrial Revolution, anthropogenically produced CO2 has resulted in an increase in global temperatures and a decline in the mean pH of the world's oceans. The California Current System is a particularly susceptible region to ocean acidification due to natural upwelling processes that also cause a reduction in seawater pH. The trace element concentration of magnesium and boron in planktonic foraminiferal shells are used here as proxies for temperature and carbonate ion concentration ([CO32-]), respectively. Newly developed calibrations relating Mg/Ca ratios to temperature (R2 0.91) and B/Ca ratios to [CO32-] (R2 0.84) for the surface-mixed layer species Globogerina bulloides were generated using material collected in the Santa Barbara Basin sediment trap time-series. Using these empirical relationships, temperature and [CO32-] are reconstructed using a 0.5 meter long multi-core collected within the basin. 210Pb activities were used to determine a sedimentation rate for the core to estimate ages for core samples (sedimentation rate: 0.341 cm/yr). A spike in 137Cs activity is used as a tie-point to the year 1965 coinciding with the peak of nuclear bomb testing. Our down-core record extends through the mid-19th century to create a history of rising sea surface temperatures and declining [CO32-] as a result of anthropogenic CO2 emissions.

  9. Applying a regional hydrology model to evaluate locations for groundwater replenishment with hillslope runoff under different climate and land use scenarios in an agricultural basin, central coastal California

    Science.gov (United States)

    Beganskas, S.; Young, K. S.; Fisher, A. T.; Lozano, S.; Harmon, R. E.; Teo, E. K.

    2017-12-01

    We are applying a regional hydrology model, Precipitation-Runoff Modeling System (PRMS), to evaluate locations for groundwater replenishment with hillslope runoff in the Pajaro Valley Groundwater Basin (PVGB), central coastal California. Stormwater managed aquifer recharge (MAR) projects collect hillslope runoff before it reaches a stream and infiltrate it into underlying aquifers, improving groundwater supply. The PVGB is a developed agricultural basin where groundwater provides >85% of water for irrigation and municipal needs; stormwater-MAR projects are being considered to address chronic overdraft and saltwater intrusion. We are applying PRMS to assess on a subwatershed scale (10-100 ha; 25-250 acres) where adequate runoff is generated to supply stormwater-MAR in coincidence with suitable conditions for infiltration and recharge. Data from active stormwater-MAR projects in the PVGB provide ground truth for model results. We are also examining how basinwide hydrology responds to changing land use and climate, and the potential implications for future water management. To prepare extensive input files for PRMS models, we developed ArcGIS and Python tools to delineate a topographic model grid and incorporate high-resolution soil, vegetation, and other physical data into each grid region; we also developed tools to analyze and visualize model output. Using historic climate records, we generated dry, normal, and wet climate scenarios, defined as having approximately 25th, 50th, and 75th percentile annual rainfall, respectively. We also generated multiple land use scenarios by replacing developed areas with native vegetation. Preliminary results indicate that many parts of the PVGB generate significant runoff and have suitable infiltration/recharge conditions. Reducing basinwide overdraft by 10% would require collecting less than 5% of total hillslope runoff, even during the dry scenario; this demonstrates that stormwater-MAR could be an effective water management

  10. Simulated hydrologic responses to climate variations and change in the Merced, Carson, and American River basins, Sierra Nevada, California, 1900-2099 *

    Science.gov (United States)

    Dettinger, M.D.; Cayan, D.R.; Meyer, M.K.; Jeton, A.

    2004-01-01

    Hydrologic responses of river basins in the Sierra Nevada of California to historical and future climate variations and changes are assessed by simulating daily streamflow and water-balance responses to simulated climate variations over a continuous 200-yr period. The coupled atmosphere-ocean-ice-land Parallel Climate Model provides the simulated climate histories, and existing hydrologic models of the Merced, Carson, and American Rivers are used to simulate the basin responses. The historical simulations yield stationary climate and hydrologic variations through the first part of the 20th century until about 1975 when temperatures begin to warm noticeably and when snowmelt and streamflow peaks begin to occur progressively earlier within the seasonal cycle. A future climate simulated with business-as-usual increases in greenhouse-gas and aerosol radiative forcings continues those recent trends through the 21st century with an attendant +2.5??C warming and a hastening of snowmelt and streamflow within the seasonal cycle by almost a month. The various projected trends in the business-as-usual simulations become readily visible despite realistic simulated natural climatic and hydrologic variability by about 2025. In contrast to these changes that are mostly associated with streamflow timing, long-term average totals of streamflow and other hydrologic fluxes remain similar to the historical mean in all three simulations. A control simulation in which radiative forcings are held constant at 1995 levels for the 50 years following 1995 yields climate and streamflow timing conditions much like the 1980s and 1990s throughout its duration. The availability of continuous climate-change projection outputs and careful design of initial conditions and control experiments, like those utilized here, promise to improve the quality and usability of future climate-change impact assessments.

  11. Environmental changes in the Tule Lake basin, Siskiyou and Modoc Counties, California, from 3 to 2 million years before present

    Science.gov (United States)

    Adam, David P.; Bradbury, J. Platt; Rieck, Hugh J.; Sarna-Wojcicki, Andrei M.

    1990-01-01

    Pollen and diatom analyses of a core from the town of Tulelake, Siskiyou County, California, for the period between 3 and 2 Ma reveal a paleoclimatic and paleolimnologic sequence recording a long, warm time interval that lasted from about 2.9 to 2.6 Ma and had a short, cooler interval within it. During this warm interval, the regional vegetation surrounding ancient Tule Lake was a mixed coniferous forest, and Tule Lake was a warm monomictic lake. Approximate modern analogs for this Pliocene fossil record at Tulelake are found at least 2 degrees farther south. The Tulelake warm interval appears to have correlatives in the North Atlantic oxygen isotope record and in the pollen record of the Reuverian in the Netherlands. An interval beginning at about 2.4 Ma was characterized at Tule Lake by slow sedimentation, by changes in the relative amounts of algae in the lake, and by an increase in the maximum percentages of Artemisia pollen.

  12. Water-quality data for the Russian River Basin, Mendocino and Sonoma Counties, California, 2005-2010

    Science.gov (United States)

    Anders, Robert; Davidek, Karl; Stoeckel, Donald M.

    2011-01-01

    Since 2003, the U.S. Geological Survey, in cooperation with the Sonoma County Water Agency, has been collecting chemical, microbiological, and isotopic data from surface-water and groundwater sites in Mendocino and Sonoma Counties, California. The investigation is being conducted to determine water-quality baseline conditions for the Russian River during the summer months and to characterize the water-quality in the area of the Sonoma County Water Agency's water-supply facility where Russian River water is diverted and treated by riverbank filtration. This report is a compilation of the hydrologic and water-quality data collected from 14 Russian River sites, 8 tributary sites, 1 gravel-terrace pit site, 14 groundwater wells, and a wastewater treatment plant between the city of Ukiah and the town of Duncans Mills for the period August 2005 through October 2010.

  13. Water-quality data from 2002 to 2003 and analysis of data gaps for development of total maximum daily loads in the Lower Klamath River Basin, California

    Science.gov (United States)

    Flint, Lorraine E.; Flint, Alan L.; Curry, Debra S.; Rounds, Stewart A.; Doyle, Micelis C.

    2004-01-01

    The U.S. Geological Survey (USGS) collected water-quality data during 2002 and 2003 in the Lower Klamath River Basin, in northern California, to support studies of river conditions as they pertain to the viability of Chinook and Coho salmon and endangered suckers. To address the data needs of the North Coast Regional Water Quality Control Board for the development of Total Maximum Daily Loads (TMDLs), water temperature, dissolved oxygen, specific conductance, and pH were continuously monitored at sites on the Klamath, Trinity, Shasta, and Lost Rivers. Water-quality samples were collected and analyzed for selected nutrients, organic carbon, chlorophyll-a, pheophytin-a, and trace elements. Sediment oxygen demand was measured on the Shasta River. Results of analysis of the data collected were used to identify locations in the Lower Klamath River Basin and periods of time during 2002 and 2003 when river conditions were more likely to be detrimental to salmonid or sucker health because of occasional high water temperatures, low dissolved oxygen, and conditions that supported abundant populations of algae and aquatic plants. The results were also used to assess gaps in data by furthering the development of the conceptual model of water flow and quality in the Lower Klamath River Basin using available data and the current understanding of processes that affect water quality and by assessing needs for the develoment of mathematical models of the system. The most notable gap in information for the study area is in sufficient knowledge about the occurrence and productivity of algal communities. Other gaps in data include vertical water-quality profiles for the reservoirs in the study area, and in an adequate understanding of the chemical oxygen demands and the sediment oxygen demands in the rivers and of the influence of riparian shading on the rivers. Several mathematical models are discussed in this report for use in characterizing the river systems in the study area; also

  14. Paleoceanographic history of the Guaymas Basin, Gulf of California, during the past 15,000 years based on diatoms, silicoflagellates, and biogenic sediments

    Science.gov (United States)

    Barron, J.A.; Bukry, D.; Dean, W.E.

    2005-01-01

    High-resolution records of calcium carbonate, biogenic opal, diatoms, and silicoflagellates from western Guaymas Basin gravity core GGC55 and piston core JPC56 and eastern Guaymas Basin DSDP Site 480 reveal a complex paleoceanographic history of the central Gulf of California during the past 15,000 years. Prior to ??? 6.2 ka, the eastern and western Guaymas Basin proxy records were remarkably similar. After conditions similar to those of today during the B??lling-Allerod, the Younger Dryas (YD) saw a major drop in diatom production, coincident with increased calcium carbonate and tropical microfossils suggestive of El Nin??o-like conditions. Biosiliceous productivity began increasing during the latter part of the YD, but it was only during the earliest Holocene (11.6 to 11.0 ka) that conditions similar to those of the B??lling-Allerod returned to the central Gulf. Between around 11.0 and 6.2 ka, tropical diatoms and silicoflagellates were virtually absent from the central Gulf, as relatively cooler and fresher surface waters resembling those of the modern northern Gulf were present in the central Gulf. Beginning at about 6.2 ka, tropical diatoms and silicoflagellates began increasing in the central Gulf, and coccoliths returned to western Gulf sediments. The onset of modern-day monsoon conditions in the American Southwest required the presence of warm SSTs in the northern Gulf, which probably did not occur until after about 5.4 ka, when tropical diatoms and silicoflagellates became relatively common in the central Gulf. Modern east-west contrasts, which arise from late winter-early spring coastal upwelling on the mainland side and lower diatom productivity on the western side of the Gulf, commenced between 6.2 and 5.4 ka, possibly due to a shift in the direction of late winter-early spring winds more towards the southeast, or down the axis of the Gulf. This proposed wind shift might have ultimately been due to a late Holocene strengthening of ENSO-like conditions

  15. Reconstruction of past climate variability and ENSO-like fluctuations in the southern Gulf of California (Alfonso Basin) since the last glacial maximum

    Science.gov (United States)

    Staines-Urías, Francisca; González-Yajimovich, Oscar; Beaufort, Luc

    2015-05-01

    Nannofossil assemblages from core MD02-2510 provide a 22 ka record of past oceanographic variability in Alfonso Basin (Gulf of California, east subtropical Pacific). In this area, environmental conditions depend on a monsoonal system heavily influenced by changes in the location of the ITCZ and nearby atmospheric pressure centers. To reconstruct nutricline depth and ENSO-like variability, two ecological indexes were calculated based on the relative abundance of the three dominant coccolith species. The late glacial period is characterized by intensified wind-driven upwelling, high primary productivity and La Niña-like conditions. An environmental shift occurs during the glacial-interglacial transition, El Niño-like conditions intensify, nutricline deepens and surface productivity declines. The late Holocene is characterized by a persistent increase in nutricline depth and dominance of El Niño-like conditions. The fluctuations in the composition of the coccolith assemblages can be related to orbital-scale fluctuations in the average position of the ITCZ. However, while the ENSO-like signal that overprints the record varies in response to orbital forcing, on suborbital time scales the relation between ENSO-like conditions and the average position of the ITCZ and the North Pacific High changes, suggesting that the development of persistent El Niño-like conditions is strongly dependent on the specific climatic background.

  16. Status and understanding of groundwater quality in the Cascade Range and Modoc Plateau study unit, 2010: California GAMA Priority Basin Project

    Science.gov (United States)

    Fram, Miranda S.; Shelton, Jennifer L.

    2015-01-01

    Groundwater quality in the Cascade Range and Modoc Plateau study unit was investigated as part of the California State Water Resources Control Board’s Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Project. The study was designed to provide a statistically unbiased assessment of untreated groundwater quality in the primary aquifer system. The depth of the primary aquifer system for the Cascade Range and Modoc Plateau study unit was delineated by the depths of the screened or open intervals of wells in the State of California’s database of public-supply wells. Two types of assessments were made: a status assessment that described the current quality of the groundwater resource, and an understanding assessment that made evaluations of relations between groundwater quality and potential explanatory factors representing characteristics of the primary aquifer system. The assessments characterize the quality of untreated groundwater, not the quality of treated drinking water delivered to consumers by water distributors.

  17. Estimating evapotranspiration change due to forest treatment and fire at the basin scale in the Sierra Nevada, California

    Science.gov (United States)

    Roche, J. W.; Goulden, M.; Bales, R. C.

    2017-12-01

    Increased forest evapotranspiration (ET) coupled with snowpack decreases in a warming climate is likely to decrease runoff and increase forest drought stress. Field experiments and modeling suggest that forest thinning can reduce ET and thus increase potential runoff relative to untreated areas. We investigated the potential magnitude and duration of ET decreases resulting from forest-thinning treatments and fire using a robust empirical relation between Landsat-derived mean-annual normalized difference vegetation index (NDVI) and annual ET measured at flux towers. Among forest treatments, the minimum observed NDVI change required to produce a significant departure from control plots with NDVI of about 0.70 was -0.07 units, corresponding to a basal-area reduction of 3.1 m2 ha-1, and equivalent to an estimated ET reduction of -102 mm yr-1. Intensive thinning in highly productive forests that approached pre-fire-exclusion densities reduced basal area by 40-50%, generating estimated ET reductions of 152-216 mm yr-1 over five years following treatment. Between 1990 and 2008, fires in the American River basin generated more than twice the ET reduction per unit area than those in the Kings River basin, corresponding to greater water and energy limitations in the latter and greater fire severity in the former. A rough extrapolation of these results to the entire American River watershed, much of which would have burned naturally during this 19-year period, could result in ET reductions that approach 10% of full natural flows for drought years and 5% averaged over all years. This work demonstrates the potential utility to estimate forest ET change at the patch scale, which in turn may allow managers to estimate thinning benefits in areas lacking detailed hydrologic measurements.

  18. Application and evaluation of electromagnetic methods for imaging saltwater intrusion in coastal aquifers: Seaside Groundwater Basin, California

    Science.gov (United States)

    Nenna, Vanessa; Herckenrather, Daan; Knight, Rosemary; Odlum, Nick; McPhee, Darcy

    2013-01-01

    Developing effective resource management strategies to limit or prevent saltwater intrusion as a result of increasing demands on coastal groundwater resources requires reliable information about the geologic structure and hydrologic state of an aquifer system. A common strategy for acquiring such information is to drill sentinel wells near the coast to monitor changes in water salinity with time. However, installation and operation of sentinel wells is costly and provides limited spatial coverage. We studied the use of noninvasive electromagnetic (EM) geophysical methods as an alternative to installation of monitoring wells for characterizing coastal aquifers. We tested the feasibility of using EM methods at a field site in northern California to identify the potential for and/or presence of hydraulic communication between an unconfined saline aquifer and a confined freshwater aquifer. One-dimensional soundings were acquired using the time-domain electromagnetic (TDEM) and audiomagnetotelluric (AMT) methods. We compared inverted resistivity models of TDEM and AMT data obtained from several inversion algorithms. We found that multiple interpretations of inverted models can be supported by the same data set, but that there were consistencies between all data sets and inversion algorithms. Results from all collected data sets suggested that EM methods are capable of reliably identifying a saltwater-saturated zone in the unconfined aquifer. Geophysical data indicated that the impermeable clay between aquifers may be more continuous than is supported by current models.

  19. Ring-Shaped Seismicity Structures in Southern California: Possible Preparation for Large Earthquake in the Los Angeles Basin

    Science.gov (United States)

    Kopnichev, Yu. F.; Sokolova, I. N.

    2017-12-01

    Some characteristics of seismicity in Southern California are studied. It is found that ring-shaped seismicity structures with threshold magnitudes M th of 4.1, 4.1, and 3.8 formed prior to three large ( M w > 7.0) earthquakes in 1992, 1999, and 2010, respectively. The sizes of these structures are several times smaller than for intracontinental strike-slip events with similar magnitudes. Two ring-shaped structures are identified in areas east of the city of Los Angeles, where relatively large earthquakes have not occurred for at least 150 years. The magnitudes of large events which can occur in the areas of these structures are estimated on the basis of the previously obtained correlation dependence of ring sizes on magnitudes of the strike-slip earthquakes. Large events with magnitudes of M w = 6.9 ± 0.2 and M w = 8.6 ± 0.2 can occur in the area to the east of the city of Los Angeles and in the rupture zone of the 1857 great Fort Tejon earthquake, respectively. We believe that ring-structure formation, similarly to the other regions, is connected with deep-seated fluid migration.

  20. Fault Length Vs Fault Displacement Evaluation In The Case Of Cerro Prieto Pull-Apart Basin (Baja California, Mexico) Subsidence

    Science.gov (United States)

    Glowacka, E.; Sarychikhina, O.; Nava Pichardo, F. A.; Farfan, F.; Garcia Arthur, M. A.; Orozco, L.; Brassea, J.

    2013-05-01

    The Cerro Prieto pull-apart basin is located in the southern part of San Andreas Fault system, and is characterized by high seismicity, recent volcanism, tectonic deformation and hydrothermal activity (Lomnitz et al, 1970; Elders et al., 1984; Suárez-Vidal et al., 2008). Since the Cerro Prieto geothermal field production started, in 1973, significant subsidence increase was observed (Glowacka and Nava, 1996, Glowacka et al., 1999), and a relation between fluid extraction rate and subsidence rate has been suggested (op. cit.). Analysis of existing deformation data (Glowacka et al., 1999, 2005, Sarychikhina 2011) points to the fact that, although the extraction changes influence the subsidence rate, the tectonic faults control the spatial extent of the observed subsidence. Tectonic faults act as water barriers in the direction perpendicular to the fault, and/or separate regions with different compaction, and as effect the significant part of the subsidence is released as vertical displacement on the ground surface along fault rupture. These faults ruptures cause damages to roads and irrigation canals and water leakage. Since 1996, a network of geotechnical instruments has operated in the Mexicali Valley, for continuous recording of deformation phenomena. To date, the network (REDECVAM: Mexicali Valley Crustal Strain Measurement Array) includes two crackmeters and eight tiltmeters installed on, or very close to, the main faults; all instruments have sampling intervals in the 1 to 20 minutes range. Additionally, there are benchmarks for measuring vertical fault displacements for which readings are recorded every 3 months. Since the crackmeter measures vertical displacement on the fault at one place only, the question appears: can we use the crackmeter data to evaluate how long is the lenth of the fractured fault, and how quickly it grows, so we can know where we can expect fractures in the canals or roads? We used the Wells and Coppersmith (1994) relations between

  1. Long period variability of a High Resolution Hydraulic Balance Proxy for Southern California and Northwestern Mexico: A 50 ka-long Sediment Record from Laguna Salada Basin, Baja California, Mexico

    Science.gov (United States)

    Aco-Palestina, A.; Contreras, J.; Martin-Barajas, A.; Hergeura, J. C.; Rendon-Marquez, G.

    2005-12-01

    The Salton Trough region of southern California and the Mexicali valley in northwestern Mexico are areas of rapid subsidence due to extension along the San Andreas-Imperial fault system and are being filled by clastic sediments transported by the Colorado River. The relatively high sedimentation rates of these basins have a high potential to preserve high-resolution climatic information. With this goal in mind, we drilled a 42 m-long core in the center of the Laguna Salada, a lacustrine basin located west of the Mexicali valley and to the south of the Salton Trough. Two 14C dates from plant remnants indicate sedimentation rates are in the order of 1mm/yr; based on this we estimate the age of the bottom of the core close to 50 Ka. This high sedimentation rate could in principle allow us to reconstruct the climatic variability of this hyperarid region on timescales ranging from centennial and millennial periodicities up to Milankovitch forcing. Here we present data on the first-order changes introduced by the later longer periods. Sedimentary facies in the core were identified based on color, granulometry, mineralogical composition and primary structures such as laminations, dissecation cracks, and bioturbation. Additionally, we obtained reflectivity of sediments every 5 mm to 1 cm, depending on the scale of primary structures. The recovered stratigraphy consists of three sedimentary successions. The lower part of the core is characterized by an alternation of mud and silt laminae of varying thickness between 5mm-1cm, probably deposited during stage 3. This ancient paleolake was dominated by sub-aqueous conditions with a permanent water table year-round. Good preservation of laminae suggests seasonal bottom anoxia. During the last glacial maximum, moisture conditions changed drastically. Laminations are replaced by finely stratified sand and further upsection by repetitive packages 50cm-thick composed of fine sand, brown mud, greenish silt and mud, and mud, caped

  2. Thermal and geochemical influences on microbial biogeography in the hydrothermal sediments of Guaymas Basin, Gulf of California.

    Science.gov (United States)

    McKay, Luke; Klokman, Vincent W; Mendlovitz, Howard P; LaRowe, Douglas E; Hoer, Daniel R; Albert, Daniel; Amend, Jan P; Teske, Andreas

    2016-02-01

    Extreme thermal gradients and compressed metabolic zones limit the depth range of microbial colonization in hydrothermally active sediments at Guaymas Basin. We investigated the physicochemical characteristics of this ecosystem and their influence on microbial community structure. Temperature-related trends of δ(13)C values of methane and dissolved inorganic carbon from 36 sediment cores suggest in situ thermal limits for microbial anaerobic methane oxidation and organic carbon re-mineralization near 80°C and 100°C respectively. Temperature logging probes deposited in hydrothermal sediments for 8 days demonstrate substantial thermal fluctuations of up to 25°C. Putative anaerobic methanotroph (ANME) populations dominate the archaeal community, transitioning from ANME-1 archaea in warm surficial sediments towards ANME-1 Guaymas archaea as temperatures increase downcore. Since ANME archaea performing anaerobic oxidation of methane double on longer time scales (months) compared with relatively rapid in situ temperature fluctuations (hours to days), we conclude that ANME archaea possess a high tolerance for short-term shifts in the thermal regime. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  3. Occurrence, distribution, and transport of pesticides, trace elements, and selected inorganic constituents into the Salton Sea Basin, California, 2001-2002

    Science.gov (United States)

    LeBlanc, Lawrence A.; Schroeder, Roy A.; Orlando, James L.; Kuivila, Kathyrn M.

    2004-01-01

    A study of pesticide distribution and transport within the Salton Sea Basin, California, was conducted from September 2001 to October 2002. Sampling for the study was done along transects for the three major rivers that flow into the Salton Sea Basin: the New and Alamo Rivers at the southern end of the basin and the Whitewater River at the northern end. Three stations were established on each river: an outlet station approximately 1 mile upstream of the river discharge, a near-shore station in the river delta, and off-shore station in the Salton Sea. Water and suspended and bed sediments were collected at each station in October 2001, March-April 2002, and September 2002, coinciding with peak pesticide applications in the fall and spring. Fourteen current-use pesticides were detected in the water column. Concentrations of dissolved pesticides typically decreased from the outlets to the sea in all three rivers, consistent with the off-shore transport of pesticides from the rivers to the sea. Dissolved concentrations ranged from the limits of detection to 151 nanograms per liter (ng/L); however, diazinon, eptam (EPTC), and malathion were detected at much higher concentrations (940?3,830 ng/L) at the New and Alamo River outlet and near-shore stations. Concentrations of carbaryl, dacthal, diazinon, and eptam were higher during the two fall sampling periods, whereas concentrations of atrazine, carbofuran, and trifluralin were higher during the spring. Current-use pesticides also were detected on suspended and bed sediments in concentrations ranging from method detection limits to 106 ng/g (nanograms per gram). Chlorpyrifos, dacthal, eptam, trifluralin, and DDE were the most frequently detected pesticides on sediments from all three rivers. The number and concentrations of pesticides associated with suspended sediments frequently were similar for the river outlet and near-shore sites, consistent with the downstream transport of sediment-associated pesticides out of the

  4. Detailed study of water quality, bottom sediment, and biota associated with irrigation drainage in the Klamath Basin, California and Oregon, 1990-92

    Science.gov (United States)

    Dileanis, Peter D.; Schwarzbach, S.E.; Bennett, Jewel

    1996-01-01

    The effect of irrigation drainage on the water quality and wildlife of the Klamath Basin in California and Oregon was evaluated during 1990-92 as part of the National Irrigation Water Quality Program of the U.S. Department of the Interior. The study focused on land serviced by the Bureau of Reclamation Klamath Project, which supplies irrigation water to agricultural land in the Klamath Basin and the Lost River Basin. The Tule Lake and Lower Klamath National Wildlife Refuges, managed by the U.S. Fish and Wildlife Service, are in the study area. These refuges provide critical resting and breeding habitat for waterfowl on the Pacific flyway and are dependent on irrigation drainwater from upstream agriculture for most of their water supply. Water-quality characteristics throughout the study area were typical of highly eutrophic systems during the summer months of 1991 and 1992. Dissolved-oxygen concentrations and pH tended to fluctuate each day in response to diurnal patterns of photosynthesis, and frequently exceeded criteria for protection of aquatic organisms. Nitrogen and phosphorus concentrations were generally at or above threshold levels characteristic of eutrophic lakes and streams. At most sites the bulk of dissolved nitrogen was organically bound. Elevated ammonia concentrations were common in the study area, especially down- stream of drain inputs. High pH of water increased the toxicity of ammonia, and concentrations exceeded criteria at sites upstream and downstream of irrigated land. Concentrations of ammonia in samples from small drains on the Tule Lake refuge leaseland were higher than those measured in the larger, integrating drains at primary monitoring sites. The mean ammonia concentration in leaseland drains [1.21 milligrams per liter (mg/L)] was significantly higher than the mean concentration in canals delivering water to the leaseland fields (0.065 mg/L) and higher than concentrations reported to be lethal to Daphnia magna (median lethal

  5. Archaeal and anaerobic methane oxidizer communities in the Sonora Margin cold seeps, Guaymas Basin (Gulf of California).

    Science.gov (United States)

    Vigneron, Adrien; Cruaud, Perrine; Pignet, Patricia; Caprais, Jean-Claude; Cambon-Bonavita, Marie-Anne; Godfroy, Anne; Toffin, Laurent

    2013-08-01

    Cold seeps, located along the Sonora Margin transform fault in the Guaymas Basin, were extensively explored during the 'BIG' cruise in June 2010. They present a seafloor mosaic pattern consisting of different faunal assemblages and microbial mats. To investigate this mostly unknown cold and hydrocarbon-rich environment, geochemical and microbiological surveys of the sediments underlying two microbial mats and a surrounding macrofaunal habitat were analyzed in detail. The geochemical measurements suggest biogenic methane production and local advective sulfate-rich fluxes in the sediments. The distributions of archaeal communities, particularly those involved in the methane cycle, were investigated at different depths (surface to 18 cm below the sea floor (cmbsf)) using complementary molecular approaches, such as Automated method of Ribosomal Intergenic Spacer Analysis (ARISA), 16S rRNA libraries, fluorescence in situ hybridization and quantitative polymerase chain reaction with new specific primer sets targeting methanogenic and anaerobic methanotrophic lineages. Molecular results indicate that metabolically active archaeal communities were dominated by known clades of anaerobic methane oxidizers (archaeal anaerobic methanotroph (ANME)-1, -2 and -3), including a novel 'ANME-2c Sonora' lineage. ANME-2c were found to be dominant, metabolically active and physically associated with syntrophic Bacteria in sulfate-rich shallow sediment layers. In contrast, ANME-1 were more prevalent in the deepest sediment samples and presented a versatile behavior in terms of syntrophic association, depending on the sulfate concentration. ANME-3 were concentrated in small aggregates without bacterial partners in a restricted sediment horizon below the first centimetres. These niche specificities and syntrophic behaviors, depending on biological surface assemblages and environmental availability of electron donors, acceptors and carbon substrates, suggest that ANME could support

  6. Relationship between in-situ stress and fractures and faults in the Monterey Formation, Santa Maria Basin, California

    Energy Technology Data Exchange (ETDEWEB)

    Finkbeiner, T.; Barton, C.A.; Zoback, M.D. (Stanford Univ., CA (United States))

    1996-01-01

    Borehole televiewer (BHTV) data from four wells within the on- and offshore Santa Maria Basin were utilized to investigate the relationship between fracture distribution, orientation, and variation with depth and in situ stress. Analysis of stress-induced wellbore breakouts in each well shows a uniform NE-SW maximum horizontal stress (S[sub Hmax]) orientation with depth. This is consistent with the regional S[sub Hmax] direction throughout the entire seismogenic part of the crust as determined from other wellbore breakout data, NW-SE trends of active fold axes and results of kinematic stress-inversion of earthquake focal plane mechanisms. In marked contrast to the uniform stress field, analysis of fractures indicates that their orientation, dip, and frequency vary considerably within each well and laterally among them. With depth, fractures can be generally divided into distinct subsets on the basis of fracture frequency and predominant strike and dip directions. These subsets correlate with changes of lithology and physical properties indicating that factors such as tectonic history, diagenesis and structural variations may have strongly influenced the initiation and propagation of fractures. Only in the onshore well do steeply-dipping fractures strike parallel to S[sub Hmax] and are interpreted as Mode I extension fractures. In the three offshore wells, the fracture strike is mainly oblique or orthogonal to S[sub Hmax] suggesting that they may be distributed strike-slip or reverse faults. We believe currently active faults in the NE-SW transpressional deformation regime play a crucial role for fluid migration by providing permeability enhanced flow paths. Drill stem tests conducted in two of the offshore wells indicate that formation permeability is greatly enhanced in sections of the well where fractures strike predominantly perpendicular to S[sub Hmax] and dip at moderate to steep angles.

  7. Relationship between in-situ stress and fractures and faults in the Monterey Formation, Santa Maria Basin, California

    Energy Technology Data Exchange (ETDEWEB)

    Finkbeiner, T.; Barton, C.A.; Zoback, M.D. [Stanford Univ., CA (United States)

    1996-12-31

    Borehole televiewer (BHTV) data from four wells within the on- and offshore Santa Maria Basin were utilized to investigate the relationship between fracture distribution, orientation, and variation with depth and in situ stress. Analysis of stress-induced wellbore breakouts in each well shows a uniform NE-SW maximum horizontal stress (S{sub Hmax}) orientation with depth. This is consistent with the regional S{sub Hmax} direction throughout the entire seismogenic part of the crust as determined from other wellbore breakout data, NW-SE trends of active fold axes and results of kinematic stress-inversion of earthquake focal plane mechanisms. In marked contrast to the uniform stress field, analysis of fractures indicates that their orientation, dip, and frequency vary considerably within each well and laterally among them. With depth, fractures can be generally divided into distinct subsets on the basis of fracture frequency and predominant strike and dip directions. These subsets correlate with changes of lithology and physical properties indicating that factors such as tectonic history, diagenesis and structural variations may have strongly influenced the initiation and propagation of fractures. Only in the onshore well do steeply-dipping fractures strike parallel to S{sub Hmax} and are interpreted as Mode I extension fractures. In the three offshore wells, the fracture strike is mainly oblique or orthogonal to S{sub Hmax} suggesting that they may be distributed strike-slip or reverse faults. We believe currently active faults in the NE-SW transpressional deformation regime play a crucial role for fluid migration by providing permeability enhanced flow paths. Drill stem tests conducted in two of the offshore wells indicate that formation permeability is greatly enhanced in sections of the well where fractures strike predominantly perpendicular to S{sub Hmax} and dip at moderate to steep angles.

  8. Major and trace-element analyses of acid mine waters in the Leviathan Mine drainage basin, California/Nevada; October, 1981 to October, 1982

    Science.gov (United States)

    Ball, J.W.; Nordstrom, D. Kirk

    1985-01-01

    Water issuing from the inactive Leviathan open-pit sulfur mine has caused serious degradation of the water quality in the Leviathan/Bryant Creek drainage basin which drains into the East Fork of the Carson River. As part of a pollution abatement project of the California Regional Water Quality Control Board, the U.S. Geological Survey collected hydrologic and water quality data for the basin during 1981-82. During this period a comprehensive sampling survey was completed to provide information on trace metal attenuation during downstream transport and to provide data for interpreting geochemical processes. This report presents the analytical results from this sampling survey. Sixty-seven water samples were filtered and preserved on-site at 45 locations and at 3 different times. Temperature, discharge, pH, and Eh and specific conductance were measured on-site. Concentrations of 37 major and trace constituents were determined later in the laboratory on preserved samples. The quality of the analyses was checked by using two or more techniques to determine the concentrations including d.c.-argon plasma emission spectrometry (DCP), flame and flameless atomic absorption spectrophotometry, UV-visible spectrophotometry, hydride-generation atomic absorption spectrophotometry and ion chromatography. Additional quality control was obtained by comparing measured to calculated conductance, comparing measured to calculated Eh (from Fe-2 +/Fe-3+ determinations), charge balance calculations and mass balance calculations for conservative constituents at confluence points. Leviathan acid mine waters contain mg/L concentrations of As, Cr, Co, Cu, Mn, Ni, T1, V and Zn, and hundreds to thousands of mg/L concentrations of Al, Fe, and sulfate at pH values as low as 1.8. Other elements including Ba, B, Be, Bi, Cd , Mo, Sb, Se and Te are elevated above normal background concentrations and fall in the microgram/L range. The chemical and 34 S/32 S isotopic analyses demonstrate that these

  9. Effects of Climate Change on Production of Siliceous Phytoplankton Over the Twentieth Century as Recorded in Sediments of the Santa Bárbara Basin off Southern California

    Science.gov (United States)

    Martinez Lopez, A.; Baumgartner, T. R.; Lange, C.

    2007-05-01

    The relationship between production of siliceous phytoplankton and interannual through multidecadal climate variability is examined by analysis of a high-resolution paleo-record of diatoms and silicoflagellates for the period 1909-1991. The record is reconstructed from the annually layered sediments (varves) preserved in the hypoxic Santa Barbara Basin providing an annual history of production and settling to the sediments of an important fraction of the new production in the coastal environment. Location of the depositional site makes it sensitive to change in ocean climate governing large scale dynamics of the California Current ecosystem. Variables used for comparison to indices of large-scale climate change are: 1) total flux rate to the sediments of both diatom tests and silicoflagellates; 2) change in species richness; 3) the absolute and relative flux of specific functional groups (indicating conditions of upwelling and turbulence vs. stability in the water column); and 4) absolute and relative flux of a species assemblage identified as having warm water affinities. Although the combination of these variables indicates a response to interannual variability associated with ENSO, a more striking feature is the persistence over decadal and interdecadal periods exemplified by the steep decline and reduced values in the overall rate of flux after 1976 (indicating a response to the basin-scale climate shift in 1976-77). The most prominent feature, however, is a major shift in the nature of total flux, and particularly a drastic change in the relative abundances of two different species assemblages, from one that dominated through the first 30 years of the series to another that dominated through the final 40 years of the record. Although the exact nature and timing of this major transition cannot be ascertained because of a break in the record from 1944 through 1948, the change is clearly marked by the replacement of a group of small diatom species (indicative of

  10. Design and development of a wireless sensor network to monitor snow depth in multiple catchments in the American River basin, California: hardware selection and sensor placement techniques

    Science.gov (United States)

    Kerkez, B.; Rice, R.; Glaser, S. D.; Bales, R. C.; Saksa, P. C.

    2010-12-01

    A 100-node wireless sensor network (WSN) was designed for the purpose of monitoring snow depth in two watersheds, spanning 3 km2 in the American River basin, in the central Sierra Nevada of California. The network will be deployed as a prototype project that will become a core element of a larger water information system for the Sierra Nevada. The site conditions range from mid-elevation forested areas to sub-alpine terrain with light forest cover. Extreme temperature and humidity fluctuations, along with heavy rain and snowfall events, create particularly challenging conditions for wireless communications. We show how statistics gathered from a previously deployed 60-node WSN, located in the Southern Sierra Critical Zone Observatory, were used to inform design. We adapted robust network hardware, manufactured by Dust Networks for highly demanding industrial monitoring, and added linear amplifiers to the radios to improve transmission distances. We also designed a custom data-logging board to interface the WSN hardware with snow-depth sensors. Due to the large distance between sensing locations, and complexity of terrain, we analyzed network statistics to select the location of repeater nodes, to create a redundant and reliable mesh. This optimized network topology will maximize transmission distances, while ensuring power-efficient network operations throughout harsh winter conditions. At least 30 of the 100 nodes will actively sense snow depth, while the remainder will act as sensor-ready repeaters in the mesh. Data from a previously conducted snow survey was used to create a Gaussian Process model of snow depth; variance estimates produced by this model were used to suggest near-optimal locations for snow-depth sensors to measure the variability across a 1 km2 grid. We compare the locations selected by the sensor placement algorithm to those made through expert opinion, and offer explanations for differences resulting from each approach.

  11. Pesticides in Surface and Ground Water of the San Joaquin-Tulare Basins, California: Analysis of Available Data, 1966 Through 1992

    Science.gov (United States)

    Domagalski, Joseph L.

    1997-01-01

    Available pesticide data (1966-92) for surface and ground water were analyzed for the San Joaquin-Tulare Basins, California, one of 60 large hydrologic systems being studied as part of the National Water-Quality Assessment Program of the U.S. Geological Survey. Most of the pesticide data were for the San Joaquin Valley, one of the most intensively farmed and irrigated areas of the United States. Data were obtained from the Storage and Retrieval data base of the U.S. Environmental Protection Agency, the water-quality data base of the U.S. Geological Survey, and from data files of State agencies. Pesticides detected in surface water include organochlorine pesticides, organophosphate pesticides, carbamate pesticides, and triazine herbicides. Pesticides detected in ground water include triazine and other organonitrogen herbicides and soil fumi gants. Surface-water data indicate seasonal patterns for the detection of organophosphate and carbamate pesticides, which are attributed to their use on almond orchards and alfafa fields. Organochlorine pesticides were detected primarily in river-bed sediments. Concentrations detected in bed sediments of the San Joaquin River near Vernalis are among the highest of any major river system in the United States. Patterns and timing of pesticide use indicate that pesticides might be present in surface-water systems during most months of a year. The most commonly detected pesticide in ground water is the soil fumigant, dibromochloropropane. Dibromochloropropane, used primarily on vineyards and orchards, was detected in ground water near the city of Fresno. Triazine and other organonitrogen herbicides were detected near vineyards and orchards in the same general locations as the detections of dibromochloropropane. Pesticides were detected in ground water of the east side of the valley floor, where the soils are sandy or coarsegrained, and water-soluble pesticides with long environmental half-lives were used. In contrast, fewer

  12. Analysis of potential water-supply management options, 2010-60, and documentation of revisions to the model of the Irwin Basin Aquifer System, Fort Irwin National Training Center, California

    Science.gov (United States)

    Voronin, Lois M.; Densmore, Jill N.; Martin, Peter

    2014-01-01

    The Fort Irwin National Training Center is considering several alternatives to manage their limited water-supply sources in the Irwin Basin. An existing three-dimensional, finite-difference groundwater-flow model—the U.S. Geological Survey’s MODFLOW—of the aquifer system in the basin was updated and the initial input dataset was supplemented with groundwater withdrawal data for the period 2000–10. The updated model was then used to simulate four combinations, or scenarios, of groundwater withdrawal and recharge over the next 50 years (January 2011 through December 2060). The scenarios included combinations of continuing withdrawals from currently active production wells, supplementing any increases in demand with withdrawals from an inactive production well, reducing withdrawal amounts and rates, and reducing the discharge of treated wastewater to infiltration ponds that provide a recharge source to the underlying aquifer. Results of the simulations indicated that, depending on the scenario implemented, groundwater levels would rise (over the next 50 years) from 40 feet to as much as 65 feet in the northwestern part of the Irwin Basin, and from 5 feet to 10 feet in the southeastern part.

  13. Estimating spatially and temporally varying recharge and runoff from precipitation and urban irrigation in the Los Angeles Basin, California

    Science.gov (United States)

    Hevesi, Joseph A.; Johnson, Tyler D.

    2016-10-17

    A daily precipitation-runoff model, referred to as the Los Angeles Basin watershed model (LABWM), was used to estimate recharge and runoff for a 5,047 square kilometer study area that included the greater Los Angeles area and all surface-water drainages potentially contributing recharge to a 1,450 square kilometer groundwater-study area underlying the greater Los Angeles area, referred to as the Los Angeles groundwater-study area. The recharge estimates for the Los Angeles groundwater-study area included spatially distributed recharge in response to the infiltration of precipitation, runoff, and urban irrigation, as well as mountain-front recharge from surface-water drainages bordering the groundwater-study area. The recharge and runoff estimates incorporated a new method for estimating urban irrigation, consisting of residential and commercial landscape watering, based on land use and the percentage of pervious land area.The LABWM used a 201.17-meter gridded discretization of the study area to represent spatially distributed climate and watershed characteristics affecting the surface and shallow sub-surface hydrology for the Los Angeles groundwater study area. Climate data from a local network of 201 monitoring sites and published maps of 30-year-average monthly precipitation and maximum and minimum air temperature were used to develop the climate inputs for the LABWM. Published maps of land use, land cover, soils, vegetation, and surficial geology were used to represent the physical characteristics of the LABWM area. The LABWM was calibrated to available streamflow records at six streamflow-gaging stations.Model results for a 100-year target-simulation period, from water years 1915 through 2014, were used to quantify and evaluate the spatial and temporal variability of water-budget components, including evapotranspiration (ET), recharge, and runoff. The largest outflow of water from the LABWM was ET; the 100-year average ET rate of 362 millimeters per year (mm

  14. Diazinon and chlorpyrifos loads in precipitation and urban and agricultural storm runoff during January and February 2001 in the San Joaquin River basin, California

    Science.gov (United States)

    Zamora, Celia; Kratzer, Charles R.; Majewski, Michael S.; Knifong, Donna L.

    2003-01-01

    The application of diazinon and chlorpyrifos on dormant orchards in 2001 in the San Joaquin River Basin was 24 percent less and 3.2 times more than applications in 2000, respectively. A total of 16 sites were sampled during January and February 2001 storm events: 7 river sites, 8 precipitation sites, and 1 urban storm drain. The seven river sites were sampled weekly during nonstorm periods and more frequently during storm runoff from a total of four storms. The monitoring of storm runoff at a city storm drain in Modesto, California, occurred simultaneously with the collection of precipitation samples from eight sites during a January 2001 storm event. The highest concentrations of diazinon occurred during the storm periods for all 16 sites, and the highest concentrations of chlorpyrifos occurred during weekly nonstorm sampling for the river sites and during the January storm period for the urban storm drain and precipitation sites. A total of 60 samples (41 from river sites, 10 from precipitation sites, and 9 from the storm drain site) had diazinon concentrations greater than 0.08 ?g/L, the concentration being considered by the California Department of Fish and Game as its criterion maximum concentration for the protection of aquatic habitats. A total of 18 samples (2 from river sites, 9 from precipitation sites, and 7 from the storm drain site) exceeded the equivalent California Department of Fish and Game guideline of 0.02 ?g/L for chlorpyrifos. The total diazinon load in the San Joaquin River near Vernalis during January and February 2001 was 23.8 pounds active ingredient; of this amount, 16.9 pounds active ingredient were transported by four storms, 1.06 pounds active ingredient were transported by nonstorm events, and 5.82 pounds active ingredient were considered to be baseline loads. The total chlorpyrifos load in the San Joaquin River near Vernalis during January and February 2001 was 2.17 pounds active ingredient; of this amount, 0.702 pound active

  15. Final Report: Baseline Selenium Monitoring of Agricultural Drains Operated by the Imperial Irrigation District in the Salton Sea Basin, California

    Science.gov (United States)

    Saiki, Michael K.; Martin, Barbara A.; May, Thomas W.

    2010-01-01

    This report summarizes comprehensive findings from a 4-year-long field investigation to document baseline environmental conditions in 29 agricultural drains and ponds operated by the Imperial Irrigation District along the southern border of the Salton Sea. Routine water-quality collections and fish community assessments were conducted on as many as 16 sampling dates at roughly quarterly intervals from July 2005 to April 2009. The water-quality measurements included total suspended solids and total (particulate plus dissolved) selenium. With one exception, fish were surveyed with baited minnow traps at quarterly intervals during the same time period. However, in July 2007, fish surveys were not conducted because we lacked permission from the California Department of Fish and Game for incidental take of desert pupfish (Cyprinodon macularius), an endangered species. During April and October 2006-08, water samples also were collected from seven intensively monitored drains (which were selected from the 29 total drains) for measurement of particulate and dissolved selenium, including inorganic and organic fractions. In addition, sediment, aquatic food chain matrices [particulate organic detritus, filamentous algae, net plankton, and midge (chironomid) larvae], and two fish species (western mosquitofish, Gambusia affinis; and sailfin molly, Poecilia latipinna) were sampled from the seven drains for measurement of total selenium concentrations. The mosquitofish and mollies were intended to serve as surrogates for pupfish, which we were not permitted to sacrifice for selenium determinations. Water quality (temperature, dissolved oxygen, pH, specific conductance, and turbidity) values were typical of surface waters in a hot, arid climate. A few drains exhibited brackish, near-anoxic conditions, especially during summer and fall when water temperatures occasionally exceeded 30 degrees Celsius. Total selenium concentrations in water were directly correlated with salinity and

  16. Southeastern Power Administration 2011 Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    None

    2011-12-31

    Dear Secretary Chu: I am pleased to submit Southeastern Power Administration’s (Southeastern) fiscal year (FY) 2011 Annual Report for your review. This report reflects our agency’s programs, accomplishments, operational, and financial activities for the 12-month period beginning October 1, 2010, and ending September 31, 2011. This past year, Southeastern marketed approximately 6.2 billion kilowatt-hours of energy to 489 wholesale customers in 10 southeastern states. Revenues from the sale of this power totaled more than $264 million. With the financial assistance and support of Southeastern’s customers, funding for capitalized equipment purchases and replacements at hydroelectric facilities operated by the U.S. Army Corps of Engineers (Corps) continued in FY 2011. This funding, which totaled more than $45 million, provided much needed repairs and maintenance for aging projects in Southeastern’s marketing area. Currently, there are more than 214 customers participating in the funding efforts in the Georgia-Alabama-South Carolina, Kerr-Philpott, and Cumberland Systems of projects. Drought conditions continued in the southeastern region of the United States this past year, particularly in the Savannah River Basin. Lack of rain placed strains on our natural and financial resources. Power purchases for FY 2011 totaled approximately $38 million. About $9 million of this amount was for replacement power, which is purchased only during adverse water conditions in order to meet Southeastern’s customer contract requirements. Southeastern’s goal is to maximize the benefits of our region’s water resources. Competing uses of these resources will present another challenging year for Southeastern’s employees. With the cooperation and communication among the Department of Energy (DOE), preference customers, and Corps, I am certain Southeastern is positioned to meet these challenges in the future. We are committed to providing reliable hydroelectric power to

  17. Southeastern Power Administration 2012 Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    None

    2012-01-01

    Dear Secretary Moniz: I am pleased to submit Southeastern Power Administration’s (Southeastern) fiscal year (FY) 2012 Annual Report for your review. This report reflects our agency’s programs, accomplishments, operational, and financial activities for the 12-month period beginning October 1, 2011, and ending September 30, 2012. This past year, Southeastern marketed approximately 5.4 billion kilowatt-hours of energy to 487 wholesale customers in 10 southeastern states. Revenues from the sale of this power totaled about $263 million. With the financial assistance and support of Southeastern’s customers, funding for capitalized equipment purchases and replacements at hydroelectric facilities operated by the U.S. Army Corps of Engineers (Corps) continued in FY 2012. Currently, there are more than 214 customers participating in funding infrastructure renewal efforts of powerplants feeding the Georgia-Alabama-South Carolina, Kerr-Philpott, and Cumberland Systems. This funding, which totaled more than $71 million, provided much needed repairs and maintenance for aging projects in Southeastern’s marketing area. Drought conditions continued in the southeastern region of the United States this past year, particularly in the Savannah River Basin. Lack of rainfall strained our natural and financial resources. Power purchases for FY 2012 in the Georgia-Alabama-South Carolina System totaled approximately $29 million. About $8 million of this amount was for replacement power, which is purchased only during adverse water conditions in order to meet Southeastern’s customer contract requirements. Southeastern’s goal is to maximize the benefits of our region’s water resources. Competing uses of these resources will present another challenging year for Southeastern’s employees. With the cooperation and communication among the Department of Energy (DOE), preference customers, and Corps, I am certain Southeastern is positioned to meet these challenges in the future. We

  18. Updated study reporting levels (SRLs) for trace-element data collected for the California Groundwater Ambient Monitoring and Assessment (GAMA) Priority Basin Project, October 2009-March 2013

    Science.gov (United States)

    Davis, Tracy A.; Olsen, Lisa D.; Fram, Miranda S.; Belitz, Kenneth

    2014-01-01

    Groundwater samples have been collected in California as part of statewide investigations of groundwater quality conducted by the U.S. Geological Survey for the Groundwater Ambient Monitoring and Assessment (GAMA) Priority Basin Project (PBP). The GAMA-PBP is being conducted in cooperation with the California State Water Resources Control Board to assess and monitor the quality of groundwater resources used for drinking-water supply and to improve public knowledge of groundwater quality in California. Quality-control samples (source-solution blanks, equipment blanks, and field blanks) were collected in order to ensure the quality of the groundwater sample results. Olsen and others (2010) previously determined study reporting levels (SRLs) for trace-element results based primarily on field blanks collected in California from May 2004 through January 2008. SRLs are raised reporting levels used to reduce the likelihood of reporting false detections attributable to contamination bias. The purpose of this report is to identify any changes in the frequency and concentrations of detections in field blanks since the last evaluation and update the SRLs for more recent data accordingly. Constituents analyzed were aluminum (Al), antimony (Sb), arsenic (As), barium (Ba), beryllium (Be), boron (B), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), lead (Pb), lithium (Li), manganese (Mn), molybdenum (Mo), nickel (Ni), selenium (Se), silver (Ag), strontium (Sr), thallium (Tl), tungsten (W), uranium (U), vanadium (V), and zinc (Zn). Data from 179 field blanks and equipment blanks collected from March 2006 through March 2013 by the GAMA-PBP indicated that for trace elements that had a change in detection frequency and concentration since the previous review, the shift occurred near October 2009, in conjunction with a change in the capsule filters used by the study. Results for 89 field blanks and equipment blanks collected from October 2009 through March 2013 were

  19. Status and understanding of groundwater quality in the Tahoe-Martis, Central Sierra, and Southern Sierra study units, 2006-2007--California GAMA Priority Basin Project

    Science.gov (United States)

    Fram, Miranda S.; Belitz, Kenneth

    2012-01-01

    Groundwater quality in the Tahoe-Martis, Central Sierra, and Southern Sierra study units was investigated as part of the Priority Basin Project of the California Groundwater Ambient Monitoring and Assessment (GAMA) Program. The three study units are located in the Sierra Nevada region of California in parts of Nevada, Placer, El Dorado, Madera, Tulare, and Kern Counties. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board, in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory. The project was designed to provide statistically robust assessments of untreated groundwater quality within the primary aquifer systems used for drinking water. The primary aquifer systems (hereinafter, primary aquifers) for each study unit are defined by the depth of the screened or open intervals of the wells listed in the California Department of Public Health (CDPH) database of wells used for municipal and community drinking-water supply. The quality of groundwater in shallower or deeper water-bearing zones may differ from that in the primary aquifers; shallower groundwater may be more vulnerable to contamination from the surface. The assessments for the Tahoe-Martis, Central Sierra, and Southern Sierra study units were based on water-quality and ancillary data collected by the USGS from 132 wells in the three study units during 2006 and 2007 and water-quality data reported in the CDPH database. Two types of assessments were made: (1) status, assessment of the current quality of the groundwater resource, and (2) understanding, identification of the natural and human factors affecting groundwater quality. The assessments characterize untreated groundwater quality, not the quality of treated drinking water delivered to consumers by water purveyors. Relative-concentrations (sample concentrations divided by benchmark concentrations) were used for evaluating groundwater quality for those

  20. Status and understanding of groundwater quality in the North San Francisco Bay Shallow Aquifer study unit, 2012; California GAMA Priority Basin Project (ver. 1.1, February 2018)

    Science.gov (United States)

    Bennett, George L.

    2017-07-20

    Groundwater quality in the North San Francisco Bay Shallow Aquifer study unit (NSF-SA) was investigated as part of the Priority Basin Project of the California Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study unit is in Marin, Mendocino, Napa, Solano, and Sonoma Counties and included two physiographic study areas: the Valleys and Plains area and the surrounding Highlands area. The NSF-SA focused on groundwater resources used for domestic drinking water supply, which generally correspond to shallower parts of aquifer systems than that of groundwater resources used for public drinking water supply in the same area. The assessments characterized the quality of untreated groundwater, not the quality of drinking water.This study included three components: (1) a status assessment, which characterized the status of the quality of the groundwater resources used for domestic supply for 2012; (2) an understanding assessment, which evaluated the natural and human factors potentially affecting water quality in those resources; and (3) a comparison between the groundwater resources used for domestic supply and those used for public supply.The status assessment was based on data collected from 71 sites sampled by the U.S. Geological Survey for the GAMA Priority Basin Project in 2012. To provide context, concentrations of constituents measured in groundwater were compared to U.S. Environmental Protection Agency (EPA) and California State Water Resources Control Board Division of Drinking Water regulatory and non-regulatory benchmarks for drinking-water quality. The status assessment used a grid-based method to estimate the proportion of the groundwater resources that has concentrations of water-quality constituents approaching or above benchmark concentrations. This method provides statistically unbiased results at the study-area scale and permits comparisons to other GAMA Priority Basin Project study areas.In the NSF-SA study unit as a whole, inorganic

  1. Digital hydrographic, land use/land cover, and hydrologic unit boundary files for the Death Valley region of southern Nevada and southeastern California processed from US Geological Survey 1:100,000- and 1:250,000-scale digital data files

    Energy Technology Data Exchange (ETDEWEB)

    Turner, A.K.; D`Agnese, F.A.; Faunt, C.C.

    1996-04-01

    Digital hydrographic and land-use/land-cover data have been compiled into a digital geographic data base for an {approx}100,000-km{sup 2} area of the Southern Great Basin, the Death Valley region of southern Nevada and SE California, located between lat 35{degree}N, long 115{degree}W and lat 38{degree}N, long 118{degree}W. This region includes the Nevada Test Site at Yucca Mountain and adjacent parts of southern Nevada and eastern California. The data base was compiled from USGS data files distributed by the USGS Earth Scinece Information Center. The data files were converted into six thematic ARC/INFO map coverages representing the Death Valley region.

  2. Status and understanding of groundwater quality in the South Coast Range-Coastal study unit, 2008: California GAMA Priority Basin Project

    Science.gov (United States)

    Burton, Carmen A.; Land, Michael; Belitz, Kenneth

    2013-01-01

    Groundwater quality in the South Coast Range–Coastal (SCRC) study unit was investigated from May through November 2008 as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study unit is located in the Southern Coast Range hydrologic province and includes parts of Santa Barbara and San Luis Obispo Counties. The GAMA Priority Basin Project is conducted by the U.S. Geological Survey (USGS) in collaboration with the California State Water Resources Control Board and the Lawrence Livermore National Laboratory. The GAMA Priority Basin Project was designed to provide a statistically unbiased, spatially distributed assessment of untreated groundwater quality within the primary aquifer system. The primary aquifer system is defined as that part of the aquifer corresponding to the perforation interval of wells listed in the California Department of Public Health (CDPH) database for the SCRC study unit. The assessments for the SCRC study unit were based on water-quality and ancillary data collected in 2008 by the USGS from 55 wells on a spatially distributed grid, and water-quality data from the CDPH database. Two types of assessments were made: (1) status, assessment of the current quality of the groundwater resource, and (2) understanding, identification of the natural and human factors affecting groundwater quality. Water-quality and ancillary data were collected from an additional 15 wells for the understanding assessment. The assessments characterize untreated groundwater quality, not the quality of treated drinking water delivered to consumers by water purveyors. The first component of this study, the status assessment of groundwater quality, used data from samples analyzed for anthropogenic constituents such as volatile organic compounds (VOCs) and pesticides, as well as naturally occurring inorganic constituents such as major ions and trace elements. Although the status assessment applies to untreated

  3. Status and understanding of groundwater quality in the two southern San Joaquin Valley study units, 2005-2006 - California GAMA Priority Basin Project

    Science.gov (United States)

    Burton, Carmen A.; Shelton, Jennifer L.; Belitz, Kenneth

    2012-01-01

    Groundwater quality in the southern San Joaquin Valley was investigated from October 2005 through March 2006 as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project is conducted by the U.S. Geological Survey (USGS) in collaboration with the California State Water Resources Control Board and the Lawrence Livermore National Laboratory. There are two study units located in the southern San Joaquin Valley: the Southeast San Joaquin Valley (SESJ) study unit and the Kern County Subbasin (KERN) study unit. The GAMA Priority Basin Project in the SESJ and KERN study units was designed to provide a statistically unbiased, spatially distributed assessment of untreated groundwater quality within the primary aquifers. The status assessment is based on water-quality and ancillary data collected in 2005 and 2006 by the USGS from 130 wells on a spatially distributed grid, and water-quality data from the California Department of Public Health (CDPH) database. Data was collected from an additional 19 wells for the understanding assessment. The aquifer systems (hereinafter referred to as primary aquifers) were defined as that part of the aquifer corresponding to the perforation interval of wells listed in the CDPH database for the SESJ and KERN study units. The status assessment of groundwater quality used data from samples analyzed for anthropogenic constituents such as volatile organic compounds (VOCs) and pesticides, as well as naturally occurring inorganic constituents such as major ions and trace elements. The status assessment is intended to characterize the quality of untreated groundwater resources within the primary aquifers in the SESJ and KERN study units, not the quality of drinking water delivered to consumers. Although the status assessment applies to untreated groundwater, Federal and California regulatory and non-regulatory water-quality benchmarks that apply to drinking water are used

  4. Distribution and abundance of decapod crustacean larvae in the southeastern Bering Sea with emphasis on commercial species. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, D.A.; Incze, L.S.; Wencker, D.L.; Armstrong, J.L.

    1981-01-01

    Contents include: Distribution and abundance of king crab larvae, Paralithodes camtschatica and P. platypus in the southeast Bering Sea; Distribution and abundance of the larvae of tanner crabs in the southeastern Bering Sea; Distribution and abundance of other brachyuran larvae in the southeastern Bering Sea with emphasis on Erimacrus isenbeckii; Distribution and abundance of shrimp larvae in the southeastern Bering Sea with emphasis on pandalid species; Distribution and abundance of hermit crabs (Paguridae) in the southeasternBering Sea; Possible oil impacts on decapod larbae in the southeastern Bering Sea with emphesis on the St. George Basin.

  5. Air quality impacts of distributed power generation in the South Coast Air Basin of California 2: Model uncertainty and sensitivity analysis

    Science.gov (United States)

    Rodriguez, M. A.; Brouwer, J.; Samuelsen, G. S.; Dabdub, D.

    Uncertainty and sensitivity of ozone and PM2.5 aerosol to variations in selected input parameters are investigated with a Monte Carlo methodology using a three-dimensional air quality model. The selection of input parameters is based on their potential to affect concentration levels of ozone and PM2.5 predicted by the model and to reflect changes in emissions due to the implementation of distributed generation (DG) in the South Coast Air Basin (SoCAB) of California. Numerical simulations are performed with the CIT air quality model. Response of the CIT predictions to the variation of selected input parameters is investigated to separate the potential air quality impacts of DG from model uncertainty. This study provides a measure of the model errors for selected species concentrations. A spatial sensitivity analysis is used to investigate the effect of placing DG in specific regions of the SoCAB. In general, results show that confidence in the model results is greatest in locations where ozone and PM2.5 concentrations are the highest. Changes no greater than 80% in the nominal values of selected input variables, cause changes of 18% in ozone mixing ratios and 25% for PM2.5 aerosol concentrations. Sensitivity analysis reveals that nitrogen oxides ( NOx) emissions and side boundary conditions of volatile organic compounds (VOC) are the major contributors to uncertainty and sensitivity of ozone predictions. An increase in NOx emissions leads to reductions in ozone mixing ratios at peak times and sites where the maximum values are located. PM2.5 aerosol is most sensitive to changes in NH3 and NOx emissions. Increasing these emissions leads to higher aerosol concentrations. Sensitivity analyses show that the impacts of DG implementation are highly dependent on both space and time. In particular, ozone concentrations are reduced during the nighttime nearby locations where DGs are installed. However, during the daytime ozone concentrations increase downwind from the

  6. Asymmetrical, inversely graded, upstream-migrating cyclic steps in marine settings: Late Miocene-early Pliocene Fish Creek-Vallecito Basin, southern California

    Science.gov (United States)

    Gong, Chenglin; Chen, Liuqin; West, Logan

    2017-10-01

    Cyclic steps are ubiquitous in modern sedimentary environments, yet their recognition remains sparse in the rock record. Here, we interpret three sets of undulating backsets (1 to 3) recognized in the late Miocene-early Pliocene Latrania Formation in the Anza-Borrego Desert, the Fish Creek-Vallecito Basin, southern California, USA as the first cm- to dm-scale outcrop record of cyclic steps, based on asymmetrical cross-sections, upstream migration, and inversely graded laminae. Upstream migration and asymmetrical cross-sections of backsets and concomitant backset laminae are attributed to supercritical-to-subcritical flow transitions through weak hydraulic jumps, which are composed of: (i) thin (tens of centimetres) and slower (reported as flow velocities (Ū) of 0.45 to 1.45 m s- 1, with mean value of Ū = 0.89 m s- 1) subcritical (represented by internal Froude numbers (Fr) of 0.67 to 0.99, with mean value of Fr = 0.84) turbidity currents on the stoss sides, and (ii) thin (tens of centimetres) and faster (reported as Ū of 0.99 to 4.03 m s- 1, with mean value of Ū = 2.24 m s- 1) supercritical (represented by Fr of 1.84 to 3.07, with mean value of Fr = 2.42) turbidity flows on the lee sides. The inversely graded laminae in the troughs of backsets are 2 to 5 cm thick, and consist of two discrete divisions: (i) 1 to 2 cm thick, lower finer-grained divisions made up of parallel laminated siltstones, overlain by very fine- to fine-grained sandstones, and (ii) 2 to 3 cm thick, upper divisions composed of medium- to coarse-grained sandstones, with sporadic occurrence of subrounded pebbles. These inversely graded laminae are related to stratified, collisional and/or frictional traction carpets under conditions of high fall-out rates. Due to the poor preservation potential of cyclic steps, the rock record of cyclic steps is generally considered to be rare. The present outcrop-based study presents a detailed analysis of sedimentary facies, growth patterns, and flow

  7. Pesticides in Water and Suspended Sediment of the Alamo and New Rivers, Imperial Valley/Salton Sea Basin, California, 2006-2007

    Science.gov (United States)

    Orlando, James L.; Smalling, Kelly L.; Kuivila, Kathryn

    2008-01-01

    Water and suspended-sediment samples were collected at eight sites on the Alamo and New Rivers in the Imperial Valley/Salton Sea Basin of California and analyzed for both current-use and organochlorine pesticides by the U.S. Geological Survey. Samples were collected in the fall of 2006 and spring of 2007, corresponding to the seasons of greatest pesticide use in the basin. Large-volume water samples (up to 650 liters) were collected at each site and processed using a flow-through centrifuge to isolate suspended sediments. One-liter water samples were collected from the effluent of the centrifuge for the analysis of dissolved pesticides. Additional samples were collected for analysis of dissolved organic carbon and for suspended-sediment concentrations. Water samples were analyzed for a suite of 61 current-use and organochlorine pesticides using gas chromatography/mass spectrometry. A total of 25 pesticides were detected in the water samples, with seven pesticides detected in more than half of the samples. Dissolved concentrations of pesticides observed in this study ranged from below their respective method detection limits to 8,940 nanograms per liter (EPTC). The most frequently detected compounds in the water samples were chlorpyrifos, DCPA, EPTC, and trifluralin, which were observed in more than 75 percent of the samples. The maximum concentrations of most pesticides were detected in samples from the Alamo River. Maximum dissolved concentrations of carbofuran, chlorpyrifos, diazinon, and malathion exceeded aquatic life benchmarks established by the U.S. Environmental Protection Agency for these pesticides. Suspended sediments were analyzed for 87 current-use and organochlorine pesticides using microwave-assisted extraction, gel permeation chromatography for sulfur removal, and either carbon/alumina stacked solid-phase extraction cartridges or deactivated Florisil for removal of matrix interferences. Twenty current-use pesticides were detected in the suspended

  8. Geostatistical analysis of tritium, groundwater age and other noble gas derived parameters in California.

    Science.gov (United States)

    Visser, A; Moran, J E; Hillegonds, Darren; Singleton, M J; Kulongoski, Justin T; Belitz, Kenneth; Esser, B K

    2016-03-15

    Key characteristics of California groundwater systems related to aquifer vulnerability, sustainability, recharge locations and mechanisms, and anthropogenic impact on recharge are revealed in a spatial geostatistical analysis of a unique data set of tritium, noble gases and other isotopic analyses unprecedented in size at nearly 4000 samples. The correlation length of key groundwater residence time parameters varies between tens of kilometers ((3)H; age) to the order of a hundred kilometers ((4)Heter; (14)C; (3)Hetrit). The correlation length of parameters related to climate, topography and atmospheric processes is on the order of several hundred kilometers (recharge temperature; δ(18)O). Young groundwater ages that highlight regional recharge areas are located in the eastern San Joaquin Valley, in the southern Santa Clara Valley Basin, in the upper LA basin and along unlined canals carrying Colorado River water, showing that much of the recent recharge in central and southern California is dominated by river recharge and managed aquifer recharge. Modern groundwater is found in wells with the top open intervals below 60 m depth in the southeastern San Joaquin Valley, Santa Clara Valley and Los Angeles basin, as the result of intensive pumping and/or managed aquifer recharge operations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Effects of smectite on the oil-expulsion efficiency of the Kreyenhagen Shale, San Joaquin Basin, California, based on hydrous-pyrolysis experiments

    Science.gov (United States)

    Lewan, Michael D.; Dolan, Michael P.; Curtis, John B.

    2014-01-01

    The amount of oil that maturing source rocks expel is expressed as their expulsion efficiency, which is usually stated in milligrams of expelled oil per gram of original total organic carbon (TOCO). Oil-expulsion efficiency can be determined by heating thermally immature source rocks in the presence of liquid water (i.e., hydrous pyrolysis) at temperatures between 350°C and 365°C for 72 hr. This pyrolysis method generates oil that is compositionally similar to natural crude oil and expels it by processes operative in the subsurface. Consequently, hydrous pyrolysis provides a means to determine oil-expulsion efficiencies and the rock properties that influence them. Smectite in source rocks has previously been considered to promote oil generation and expulsion and is the focus of this hydrous-pyrolysis study involving a representative sample of smectite-rich source rock from the Eocene Kreyenhagen Shale in the San Joaquin Basin of California. Smectite is the major clay mineral (31 wt. %) in this thermally immature sample, which contains 9.4 wt. % total organic carbon (TOC) comprised of type II kerogen. Compared to other immature source rocks that lack smectite as their major clay mineral, the expulsion efficiency of the Kreyenhagen Shale was significantly lower. The expulsion efficiency of the Kreyenhagen whole rock was reduced 88% compared to that of its isolated kerogen. This significant reduction is attributed to bitumen impregnating the smectite interlayers in addition to the rock matrix. Within the interlayers, much of the bitumen is converted to pyrobitumen through crosslinking instead of oil through thermal cracking. As a result, smectite does not promote oil generation but inhibits it. Bitumen impregnation of the rock matrix and smectite interlayers results in the rock pore system changing from water wet to bitumen wet. This change prevents potassium ion (K+) transfer and dissolution and precipitation reactions needed for the conversion of smectite to

  10. Methods for determining magnitude and frequency of floods in California, based on data through water year 2006

    Science.gov (United States)

    Gotvald, Anthony J.; Barth, Nancy A.; Veilleux, Andrea G.; Parrett, Charles

    2012-01-01

    Methods for estimating the magnitude and frequency of floods in California that are not substantially affected by regulation or diversions have been updated. Annual peak-flow data through water year 2006 were analyzed for 771 streamflow-gaging stations (streamgages) in California having 10 or more years of data. Flood-frequency estimates were computed for the streamgages by using the expected moments algorithm to fit a Pearson Type III distribution to logarithms of annual peak flows for each streamgage. Low-outlier and historic information were incorporated into the flood-frequency analysis, and a generalized Grubbs-Beck test was used to detect multiple potentially influential low outliers. Special methods for fitting the distribution were developed for streamgages in the desert region in southeastern California. Additionally, basin characteristics for the streamgages were computed by using a geographical information system. Regional regression analysis, using generalized least squares regression, was used to develop a set of equations for estimating flows with 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities for ungaged basins in California that are outside of the southeastern desert region. Flood-frequency estimates and basin characteristics for 630 streamgages were combined to form the final database used in the regional regression analysis. Five hydrologic regions were developed for the area of California outside of the desert region. The final regional regression equations are functions of drainage area and mean annual precipitation for four of the five regions. In one region, the Sierra Nevada region, the final equations are functions of drainage area, mean basin elevation, and mean annual precipitation. Average standard errors of prediction for the regression equations in all five regions range from 42.7 to 161.9 percent. For the desert region of California, an analysis of 33 streamgages was used to develop regional estimates

  11. Crustal investigations of the earthquake-prone Vrancea region in Romania - Part 2: Novel deep seismic reflection experiment in the southeastern Carpathian belt and its foreland basin - survey target, design, and first results

    Science.gov (United States)

    Mocanu, V. I.; Stephenson, R. A.; Diaconescu, C. C.; Knapp, J. H.; Matenco, L.; Dinu, C.; Harder, S.; Prodehl, C.; Hauser, F.; Raileanu, V.; Cloetingh, S. A.; Leever, K.

    2001-12-01

    Seismic studies of the outer Carpathian Orogen and its foreland (Focsani Basin) in the vicinity of the Vrancea Zone and Danube Delta (Romania) forms one component of a new multidisciplinary initiative of ISES (Netherlands Centre for Integrated Solid Earth Sciences) called DACIA PLAN ("Danube and Carpathian Integrated Action on Processes in the Lithosphere and Neotectonics"). The study area, at the margin of the European craton, constitutes one of the most active seismic zones in Europe, yet has remained a geological and geodynamic enigma within the Alpine-Himalayan orogenic system. Intermediate depth (50-220 km) mantle earthquakes of significant magnitude occur in a geographically restricted area in the south-east Carpathians bend. The adjacent, foreland Focsani Basin appears to exhibit recent extensional deformation in what is otherwise understood to be a zone of convergence. The deep seismic reflection component of DACIA PLAN comprises a ~140-km near-vertical profile across the Vrancea Zone and Focsani Basin. Data acquisition took place in August-September 2001, as part of the integrated refraction/reflection seismic field programme "Vrancea-2001" co-ordinated at Karlsruhe University (cf. Abstract, Part 1), utilising 640 independently deployed recorders provided by UTEP and IRIS/PASSCAL ("Texans"). Station spacing was every 100-m with shots every 1-km. These data are to be integrated with industry seismic as well as planned new medium-high resolution seismic reflection profiling across key neotectonically active structures in the Focsani Basin. Particular goals of DACIA PLAN include: (1) the architecture of the Tertiary/Quaternary basins developed within and adjacent to this zone, including the foreland Focsani Basin; (2) the presence and geometry of structural detachment(s) in relation with foreland basin development, including constraints for balanced cross-sections and geodynamic modelling of basin origin and evolution; (3) the relationship between crustal

  12. Status and understanding of groundwater quality in the Bear Valley and Lake Arrowhead Watershed Study Unit, 2010: California GAMA Priority Basin Project

    Science.gov (United States)

    Mathany, Timothy; Burton, Carmen

    2017-06-20

    Groundwater quality in the 112-square-mile Bear Valley and Lake Arrowhead Watershed (BEAR) study unit was investigated as part of the Priority Basin Project (PBP) of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study unit comprises two study areas (Bear Valley and Lake Arrowhead Watershed) in southern California in San Bernardino County. The GAMA-PBP is conducted by the California State Water Resources Control Board (SWRCB) in cooperation with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory.The GAMA BEAR study was designed to provide a spatially balanced, robust assessment of the quality of untreated (raw) groundwater from the primary aquifer systems in the two study areas of the BEAR study unit. The assessment is based on water-quality collected by the USGS from 38 sites (27 grid and 11 understanding) during 2010 and on water-quality data from the SWRCB-Division of Drinking Water (DDW) database. The primary aquifer system is defined by springs and the perforation intervals of wells listed in the SWRCB-DDW water-quality database for the BEAR study unit.This study included two types of assessments: (1) a status assessment, which characterized the status of the quality of the groundwater resource as of 2010 by using data from samples analyzed for volatile organic compounds, pesticides, and naturally present inorganic constituents, such as major ions and trace elements, and (2) an understanding assessment, which evaluated the natural and human factors potentially affecting the groundwater quality. The assessments were intended to characterize the quality of groundwater resources in the primary aquifer system of the BEAR study unit, not the treated drinking water delivered to consumers. Bear Valley study area and the Lake Arrowhead Watershed study area were also compared statistically on the basis of water-quality results and factors potentially affecting the groundwater quality.Relative concentrations (RCs

  13. Southeastern Science Policy Colloquium

    Energy Technology Data Exchange (ETDEWEB)

    Humphries, F.

    1995-06-22

    This conference covers four main topics: (1) Southeastern Labor Market and its Impact on Corporate/Industry Development; (2) New Issues for Science and Technology in the Year 2000 and Beyond; (3) The Role of Academia in Developing the Labor Force of the Southeast; and (4) K-12 Education: Challenges for the 21st Century.

  14. Groundwater quality data in 15 GAMA study units: results from the 2006–10 Initial sampling and the 2009–13 resampling of wells, California GAMA Priority Basin Project

    Science.gov (United States)

    Kent, Robert

    2015-08-31

    The Priority Basin Project (PBP) of the Groundwater Ambient Monitoring and Assessment (GAMA) program was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). From May 2004 to March 2012, the GAMA-PBP collected samples from more than 2,300 wells in 35 study units across the State. Selected wells in each study unit were sampled again approximately 3 years after initial sampling as part of an assessment of temporal trends in water quality by the GAMA-PBP. This triennial (every 3 years) trend sampling of GAMA-PBP study units concluded in December 2013. Fifteen of the study units, initially sampled between January 2006 and June 2010 and sampled a second time between April 2009 and April 2013 to assess temporal trends, are the subject of this report.

  15. Water Resources Data for California, Water Year 1985. Volume 2. Pacific Slope Basins from Arroyo Grande to Oregon State Line except Central Valley

    Science.gov (United States)

    Anderson, S.; Markham, K.L.; Trujillo, L.F.; Shelton, W.F.; Grillo, D.A.

    1987-01-01

    Water resources data for the 1985 water year for California consists of records of stage, discharge, and water quality of streams; and stage and contents in lakes and reservoirs; and water levels and water quality in wells. Volume 2 contains discharge records for 133 gaging stations; stage and contents for 9 lakes and reservoirs; and water quality for 34 stations. Also included are 3 low-flow partial-record stations and 1 water-quality partial-record stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in California.

  16. Water Resources Data for California, Water Year 1987. Volume 2. Pacific Slope Basins from Arroyo Grande to Oregon State Line Except Central Valley

    Science.gov (United States)

    Anderson, S.; Markham, K.L.; Shelton, W.F.; Trujillo, L.F.

    1988-01-01

    Water resources data for the 1987 water year for California consist of records of stage, discharge, and water quality of streams; stage and contents in lakes and reservoirs; and water levels and water. quality in wells. Volume 2 contains discharge records for 123 gaging stations; stage and contents for 7 lakes and reservoirs; and water quality for 29 stations. Also included are 1 partial-record station and 24 water-quality partial-record stations, These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in California.

  17. Water Resources Data for California, Water Year 1988. Volume 2. Pacific Slope Basins from Arroyo Grande to Oregon State Line Except Central Valley

    Science.gov (United States)

    Markham, K.L.; Palmer, J.R.; Shelton, W.F.; Trujillo, L.F.

    1989-01-01

    Water resources data for the 1988 water year for California consist of records of stage, discharge, and water quality of streams; stage and contents in lakes and reservoirs; and water levels and water quality in wells. Volume 2 contains discharge records for 123 gaging stations; stage and contents for 7 lakes and reservoirs; and water quality for 38 stations. Also included is l low-flow partial-record station and 22 water-quality partial-record stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in California.

  18. Water Resources Data for California, Water Year 1986. Volume 2. Pacific Slope Basins from Arroyo Grande to Oregon State Line except Central Valley

    Science.gov (United States)

    Anderson, S.; Markham, K.L.; Shelton, W.F.; Trujillo, L.F.; Grillo, D.A.

    1988-01-01

    Water resources data for the 1986 water year for California consist of records of stage, discharge, and water quality of streams; stage and contents in lakes and reservoirs; and water levels and water quality in wells. Volume 2 contains discharge records for 132 gaging stations; stage and contents for 11 lakes and reservoirs; and water quality for 32 stations. Also included are 4 partial-record stations and 24 water-quality partial-record stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in California.

  19. Water Resources Data, California, Water Year 1989. Volume 2. Pacific Slope Basins from Arroyo Grande to Oregon State Line except Central Valley

    Science.gov (United States)

    Palmer, J.R.; Shelton, W.F.; Trujillo, L.F.; Markham, K.L.

    1990-01-01

    Water resources data for the 1989 water year for California consist of records of stage, discharge, and water. quality of streams; stage and contents in lakes and reservoirs; and water levels and water quality in wells. Volume 2 contains discharge records for 127 gaging stations, stage and contents for 7 lakes and reservoir and water quality for 32 stations. Also included is 1 low-flow partial-record station and 22 waterquality partial-record stations. These data represent that part of the National Water Data System operated by the u.s. Geological Survey and cooperating State and Federal agencies in California.

  20. Broadening the interpretive framework of deepwater deposits: 3D characterization of outcrop scale bedforms within supercritical dominated slope deposits of the Fish Creek-Vallecito Basin, Late-Miocene Gulf of California

    Science.gov (United States)

    West, L. M.; Steel, R.; Olariu, C.

    2017-12-01

    Study of seafloor bathymetry, numerical and physical modeling, and direct observation of turbidity currents increasingly suggests that sediment gravity flows over moderately steep basin slopes commonly reach Froude supercritical states. However, interpretation of supercritical features in deepwater outcrops remains limited in both quantity and scope, leaving stratigraphic qualities of supercritical deposits poorly understood. Slope turbidites on along steep margins of the early Gulf of California are exposed in seismic scale outcrops of the Late Miocene Lycium Member in the Fish Creek-Vallecito Basin of south-central California where they build 100s m-thick slopes. Measured sections, bedding orientation, and facies descriptions collected both for strike- and dip-oriented sections are combined with photogrammetric to characterize selected bedforms in three-dimensions. Analysis shows upflow accreting stacks of 10s of beds into a variety of bedforms with wavelengths and widths tens to hundreds of meters in scale and heights of 5-15 m. Beds have low-angle sinusoidal to sigmoidal down dip geometries and lens or lobate strike geometries. Bedding facies are dominated by 5-50 cm thick, normally graded, laminated sandstones capped by 1-3 cm bioturbated muds. Sandstones transition into interbedded sandstones and silty mudstones or 1-2 m thick silty mudstones. In places, Present also are incisional, steeply dipping backsets of 0.5-3 m-thick boulder-rich, amalgamated, structureless sandtones with abundant soft sediment deformation. that can transition downflow into arching, thinning, normally-graded sandstones. These bedforms are interpreted here as large-scale, long-lived supercritical deposits that represent preserved antidune and possibly cyclic steps bedforms or as-yet undefined bedforms incorporating by not bound by hydraulic jumps. This characterization provides new understanding of the nature of supercritical deposits and an important framework criteria for recognizing

  1. California Bioregions

    Data.gov (United States)

    California Department of Resources — California regions developed by the Inter-agency Natural Areas Coordinating Committee (INACC) were digitized from a 1:1,200,000 California Department of Fish and...

  2. California Bioregions

    Data.gov (United States)

    California Natural Resource Agency — California regions developed by the Inter-agency Natural Areas Coordinating Committee (INACC) were digitized from a 1:1,200,000 California Department of Fish and...

  3. Prediction method of sediment discharge from forested basin

    Science.gov (United States)

    Kazutoki Abe; Ushio Kurokawa; Robert R. Ziemer

    2000-01-01

    An estimation model for sediment discharge from a forested basin using Universal Soil Loss Equation and delivery ratio was developed. Study basins are North fork and South fork in Caspar Creek, north California, where Forest Service, USDA has been using water and sediment discharge from both basins since 1962. The whole basin is covered with the forest, mainly...

  4. Stratigraphy and paleogeographic significance of a Late Pennsylvanian to Early Permian channeled slope sequence in the Darwin Basin, southern Darwin Hills, east-central California

    Science.gov (United States)

    Stevens, Calvin H.; Stone, Paul; Magginetti, Robert T.; Ritter, Scott M.

    2015-01-01

    The complex stratigraphy of late Paleozoic rocks in the southern Darwin Hills consists of regionally extensive Mississippian and Early to Middle Pennsylvanian rocks overlain by latest Pennsylvanian to Early Permian rocks, herein called the Darwin Hills sequence. Deposition of this latter sequence marked the beginning of the Darwin Basin. In Mississippian time, a carbonate platform prograded westward over slightly older slope deposits. In the Late Mississippian this platform was exposed to erosion and siliciclastic sediments were deposited. In Early to Middle Pennsylvanian time the area subsided, forming a west-facing ramp that was subjected to deformation and erosion in Middle or early Late Pennsylvanian time. Later this area was tilted westward and deep-water sediments were deposited on this slope. In latest Pennsylvanian to earliest Permian time, a major channel was cut through the older Pennsylvanian rocks and into the Upper Mississippian strata. This channel was gradually filled with increasingly finer grained, deep-water sediment as the area evolved into a basin floor by Early Permian (Sakmarian) time. Expansion of the Darwin Basin in Artinskian time led to a second phase of deposition represented by strata of the regionally extensive Darwin Canyon Formation. The geology in this small area thus documents tectonic events occurring during the early development of the Darwin Basin.

  5. Aquatic macroinvertebrate diversity and composition in streams along an altitudinal gradient in Southeastern Brazil

    OpenAIRE

    Henriques-Oliveira, Ana Lucia; Nessimian, Jorge Luiz

    2010-01-01

    Aquatic macroinvertebrate diversity and composition in streams along an altitudinal gradient in Southeastern Brazil. A study concerning taxonomic richness and composition of the aquatic insect fauna in streams within the same catchment basin along an altitudinal gradient in Southeast Brazil, was conducted to test the hypothesis that there is a faunal discontinuity in the biocenotic composition, related to differences in altitude and latitude. In Southeastern Brazil, around latitude 22°, this ...

  6. Hydrogeologic setting and hydrologic data of the Smoke Creek Desert basin, Washoe County, Nevada, and Lassen County, California, water years 1988-90

    Science.gov (United States)

    Maurer, D.K.

    1993-01-01

    Smoke Creek Desert is a potential source of water for urban development in Washoe County, Nevada. Hydrogeologic data were collected from 1988 to 1990 to learn more about surface- and ground-water flow in the basin. Impermeable rocks form a boundary to ground-water flow on the east side of the basin and at unknown depths at the base of the flow system. Permeable volcanic rocks on the west and north sides of the basin represent a previously unrecognized aquifer and provide potential avenues for interbasin flow. Geophysical data indicate that basin-fill sediments are about 2,000 feet thick near the center of the basin. The geometry of the aquifers, however, remains largely unknown. Measurements of water levels, pressure head, flow rate, water temperature, and specific conductance at 19 wells show little change from 1988 to 1990. Chemically, ground water begins as a dilute sodium and calcium bicarbonate water in the mountain blocks, changes to a slightly saline sodium bicarbonate solution beneath the alluvial fans, and becomes a briny sodium chloride water near the playa. Concentrations of several inorganic constituents in the briny water near the playa commonly exceed Nevada drinking-water standards. Ground water in the Honey Lake basin and Smoke Creek Desert basin has similar stable-isotope composition, except near Sand Pass. If interbasin flow takes place, it likely occurs at depths greater than 400-600 feet beneath Sand Pass or through volcanic rocks to the north of Sand Pass. Measure- ments of streamflow indicate that about 2,800 acre-feet/year discharged from volcanic rocks to streamflow and a minimum of 7.300 acre-feet/year infiltrated and recharged unconsolidated sediments near Smoke, Buffalo, and Squaw Creeks during the period of study. Also about 1,500 acre-feet per year was lost to evapotranspiration along the channel of Smoke Creek, and about 1,680 acre-feet per year of runoff from Smoke, Buffalo, and Squaw Creeks was probably lost to evaporation from the

  7. Water Resources Data, California, Water Year 1991. Volume 2. Pacific Slope Basins from Arroyo Grande to Oregon State Line except Central Valley

    Science.gov (United States)

    Trujillo, L.F.; Markham, K.L.; Palmer, J.R.; Friebel, M.F.

    1992-01-01

    Water resources data for the 1991 water year for California consist of records of stage, discharge, and water quality of streams; stage and contents in lakes and reservoirs; and water levels and water quality in wells. Volume 2 contains discharge records for 130 streamflow-gaging stations, 1 low-flow partial-record station, and 6 miscellaneous measurement sites; stage and contents for 7 lakes and reservoirs; precipitation records for 3 stations; and water-quality records for 41 streamflow-gaging stations and 3 water-quality partial-record stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in California.

  8. Water Resources Data, California, Water Year 1990. Volume 2. Pacific Slope Basins from Arroyo Grande to Oregon State Line except Central Valley

    Science.gov (United States)

    Shelton, W.F.; Trujillo, L.F.; Markham, K.L.; Palmer, J.R.

    1991-01-01

    Water resources data for the 1990 water year for. California consist of records of stage, discharge, and water quality of streams; stage and contents in lakes and reservoirs; and water levels and water quality in wells. Volume 2 contains discharge records for 125 streamflow-gaging stations and 1 low-flow partial-record station; stage and contents for 7 lakes and reservoirs; precipitation records for 4 stations; and water-quality records for 29 streamflow-gaging stations and 10 water-quality partial-record stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in California.

  9. Fault-Related CO2 Degassing, Geothermics, and Fluid Flow in Southern California Basins--Physiochemical Evidence and Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Garven, Grant [Tufts Univ., Medford, MA (United States)

    2015-08-11

    Our studies have had an important impact on societal issues. Experimental and field observations show that CO2 degassing, such as might occur from stored CO2 reservoir gas, can result in significant stable isotopic disequilibrium. In the offshore South Ellwood field of the Santa Barbara channel, we show how oil production has reduced natural seep rates in the area, thereby reducing greenhouse gases. Permeability is calculated to be ~20-30 millidarcys for km-scale fault-focused fluid flow, using changes in natural gas seepage rates from well production, and poroelastic changes in formation pore-water pressure. In the Los Angeles (LA) basin, our characterization of formation water chemistry, including stable isotopic studies, allows the distinction between deep and shallow formations waters. Our multiphase computational-based modeling of petroleum migration demonstrates the important role of major faults on geological-scale fluid migration in the LA basin, and show how petroleum was dammed up against the Newport-Inglewood fault zone in a “geologically fast” interval of time (less than 0.5 million years). Furthermore, these fluid studies also will allow evaluation of potential cross-formational mixing of formation fluids. Lastly, our new study of helium isotopes in the LA basin shows a significant leakage of mantle helium along the Newport Inglewood fault zone (NIFZ), at flow rates up to 2 cm/yr. Crustal-scale fault permeability (~60 microdarcys) and advective versus conductive heat transport rates have been estimated using the observed helium isotopic data. The NIFZ is an important deep-seated fault that may crosscut a proposed basin decollement fault in this heavily populated area, and appears to allow seepage of helium from the mantle sources about 30 km beneath Los Angeles. The helium study has been widely cited in recent weeks by the news media, both in radio and on numerous web sites.

  10. Fault-related CO2 degassing, geothermics, and fluid flow in southern California basins---Physiochemical evidence and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Boles, James R. [Univ. of California, Santa Barbara, CA (United States); Garven, Grant [Tufts Univ., Medford, MA (United States)

    2015-08-04

    Our studies have had an important impact on societal issues. Experimental and field observations show that CO2 degassing, such as might occur from stored CO2 reservoir gas, can result in significant stable isotopic disequilibrium. In the offshore South Ellwood field of the Santa Barbara channel, we show how oil production has reduced natural seep rates in the area, thereby reducing greenhouse gases. Permeability is calculated to be ~20-30 millidarcys for km-scale fault-focused fluid flow, using changes in natural gas seepage rates from well production, and poroelastic changes in formation pore-water pressure. In the Los Angeles (LA) basin, our characterization of formation water chemistry, including stable isotopic studies, allows the distinction between deep and shallow formations waters. Our multiphase computational-based modeling of petroleum migration demonstrates the important role of major faults on geological-scale fluid migration in the LA basin, and show how petroleum was dammed up against the Newport-Inglewood fault zone in a “geologically fast” interval of time (less than 0.5 million years). Furthermore, these fluid studies also will allow evaluation of potential cross-formational mixing of formation fluids. Lastly, our new study of helium isotopes in the LA basin shows a significant leakage of mantle helium along the Newport Inglewood fault zone (NIFZ), at flow rates up to 2 cm/yr. Crustal-scale fault permeability (~60 microdarcys) and advective versus conductive heat transport rates have been estimated using the observed helium isotopic data. The NIFZ is an important deep-seated fault that may crosscut a proposed basin decollement fault in this heavily populated area, and appears to allow seepage of helium from the mantle sources about 30 km beneath Los Angeles. The helium study has been widely cited in recent weeks by the news media, both in radio and on numerous web sites.

  11. Water Resources Data, California, Water Year 1993. Volume 2. Pacific Slope Basins from Arroyo Grande to Oregon State Line except Central Valley

    Science.gov (United States)

    Palmer, J.R.; Friebel, M.F.; Trujillo, L.F.; Markham, K.L.

    1994-01-01

    Water resources data for the 1993 water year for California consist of records of stage, discharge, and water quality of streams; stage and contents in lakes and reservoirs; and water levels and water quality in wells. Volume 2 contains discharge records for 119 streamflow-gaging stations, 1 low-flow partial-record streamflow station, and 6 miscellaneous measurement stations; stage and contents records for 6 lakes and reservoirs; precipitation records for 3 stations; and water-quality records for 31 streamflow-gaging stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and with other agencies.

  12. Water Resources Data, California, Water Year 1995. Volume 2. Pacific Slope Basins from Arroyo Grande to Oregon State Line except Central Valley

    Science.gov (United States)

    Friebel, M.F.; Trujillo, L.F.; Markham, K.L.

    1996-01-01

    Water-resources data for the 1995 water year for California consist of records of stage, discharge, and water quality of streams; stage and contents in lakes and reservoirs; and water levels and water quality in wells. Volume 2 contains discharge records for 111 streamflow-gaging stations, 1 low-flow partial-record streamflow station; and 2 miscellaneous measurement stations; stage and contents for 6 lakes and reservoirs; precipitation records for 1 station; and water-quality records for 22 streamflow-gaging stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and with other agencies.

  13. Effects of human water management on California drought risk

    Science.gov (United States)

    He, Xiaogang; Wada, Yoshihide; Wanders, Niko; Sheffield, Justin

    2017-04-01

    Contribution of human water management to the intensification or mitigation of hydrological drought over California is investigated using the PCR-GLOBWB hydrological model at 0.5˚ resolution for the period 1979-2014. We demonstrate that including water management in the modeling framework results in more accurate discharge representation. During the severe 2014 drought, water management alleviated the drought deficit by ˜50% in Southern California through reservoir operation during low flow periods. However, human water consumption (mostly irrigation) in the Central Valley increased drought duration and deficit by 50% and 50-100%, respectively. Return level analysis indicates that there is more than 50% chance that the probability of occurrence of an extreme 2014-magnitude drought event was at least doubled under the influence of human activities compared to natural variability. This impact is most significant over the San Joaquin Drainage basin with a 50% and 75% likelihood that the return period is more than 3.5 and 1.5 times larger, respectively, because of the human impact on drought. A detailed study of the relative attribution of different types of human activities (e.g., groundwater pumping, reservoir operation and irrigation) on changes in drought risk over California is conducted through a higher 10 km resolution simulation. This hydrological modeling, attribution and risk assessment framework is further extended to other drought-prone areas and major drought events in the contiguous U.S., including the 2006/2007 southeastern U.S. drought, the 2011 Texas-northern Mexico drought over the southern plains and the 2012 drought over the central Great Plains.

  14. Characterization of potential transport pathways and implications for groundwater management near an anticline in the Central Basin area, Los Angeles County, California

    Science.gov (United States)

    Ponti, Daniel J.; Wagner, Brian J.; Land, Michael; Landon, Matthew K.

    2014-01-01

    The Central Groundwater Basin (Central Basin) of southern Los Angeles County includes ~280 mi2 of the Los Angeles Coastal Plain and serves as the primary source of water for more than two million residents. In the Santa Fe Springs–Whittier–Norwalk area, located in the northeastern part of the basin, several sources of volatile organic compounds have been identified. The volatile organic compunds are thought to have contributed to a large, commingled contaminant plume in groundwater that extends south-southwest downgradient from the Omega Chemical Corporation Superfund Site across folded geologic strata, known as the Santa Fe Springs Anticline. A multifaceted study—that incorporated a three-dimensional sequence-stratigraphic geologic model, two-dimensional groundwater particle-tracking simulations, and new groundwater chemistry data—was conducted to gain insight into the geologic and hydrologic controls on contaminant migration in the study area and to assess the potential for this shallow groundwater contamination to migrate into producing aquifer zones. Conceptual flow models were developed along a flow-parallel cross section based on the modeled stratigraphic architecture, observed geochemistry, and numerical model simulations that generally agree with observed water levels and contaminant distributions. These models predict that contaminants introduced into groundwater at shallow depths near the Omega Chemical Corporation Superfund Site and along the study cross section will likely migrate downgradient to depths intercepted by public supply wells. These conclusions, however, are subject to limitations and simplifications inherent in the modeling approaches used, as well as a significant scarcity of available geologic and hydrogeochemical information at depth and in the downgradient parts of the study area.

  15. Sand, salt and water in the Stampriet Basin, Namibia: Calculating ...

    African Journals Online (AJOL)

    Sand, salt and water in the Stampriet Basin, Namibia: Calculating unsaturated zone (Kalahari dunefield) .... prior to the deposition of the Kalahari Basin formed chan- nels, which in the south-eastern region of the .... Whitehill formation, and elsewhere this directly overlies the. Upper Rietmond member. The Upper Rietmond ...

  16. Sedimentation Study and Flume Investigation, Mission Creek, Santa Barbara, California; Corte Madera Creek, Marin County, California

    National Research Council Canada - National Science Library

    Copeland, Ronald

    2000-01-01

    .... An existing concrete-lined flood control channel on Corte Madera Creek in Marin County, California lacks a debris basin at its upstream terminus and carries significant bed load through a supercritical flow reach...

  17. Water Resources Data, California, Water Year 1992. Volume 2. Pacific Slope Basins from Arroyo Grande to Oregon State Line except Central Valley

    Science.gov (United States)

    Markham, K.L.; Palmer, J.R.; Friebel, M.F.; Trujillo, L.F.

    1993-01-01

    Water resources data for the 1992 water year for California consist of records of stage, discharge, and water quality of streams; stage and contents in lakes and reservoirs; and water levels and water quality in wells. Volume 2 contains discharge records for 124 streamflow-gaging stations, 1 low-flow partial-record streamflow station, and 6 miscellaneous measurement stations; stage and contents records for 9 lakes and reservoirs; precipitation records for 3 stations; and water-quality records for 32 stream flow-gaging stations and 1 water-quality partial-record station. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and with other agencies.

  18. Subsurface imaging in a sector of Cerro Prieto transform fault near to pull-apart basin, Mexicali Valley, Baja California, Mexico, based on crooked lines 2D seismic reflection.

    Science.gov (United States)

    Mares-Agüero, M. A.; González-Escobar, M.; Arregui, S.

    2016-12-01

    In the transition zone between San Andres continental transformation system and the coupled transform faults system and rifting of Gulf of California is located the Cerro Prieto pull-apart basin delimitated by Imperial fault (northeast) and Cerro Prieto fault (CPF) (southwest), this last, is the limit west of Cerro Prieto geothermic field (CPGF). Crooked lines 2D seismic reflection, covering a portion near the intersection of CPF and CPGF are processed and interpreted. The seismic data were obtained in the early 80's by Petróleos Mexicanos (PEMEX). By decades, technical and investigation works in Cerro Prieto geothermic field and its vicinity had mapped faults at several depths but do not stablish a clear limit where this faults and CPF interact due the complex hydrothermal effects imaging the subsurface. The profiles showing the presence of a zone of uplift effect due to CPF. Considering the proximity of the profiles to CPF, it is surprising almost total absence of faults. A strong reflector around 2 km of depth, it is present in all profiles. This seismic reflector is considered a layer of shale, result of the correlation with a well located in the same region.

  19. Insights into hydrologic and hydrochemical processes based on concentration-discharge and end-member mixing analyses in the mid-Merced River Basin, Sierra Nevada, California

    Science.gov (United States)

    Liu, Fengjing; Conklin, Martha H.; Shaw, Glenn D.

    2017-01-01

    Both concentration-discharge relation and end-member mixing analysis were explored to elucidate the connectivity of hydrologic and hydrochemical processes using chemical data collected during 2006-2008 at Happy Isles (468 km2), Pohono Bridge (833 km2), and Briceburg (1873 km2) in the snowmelt-fed mid-Merced River basin, augmented by chemical data collected by the USGS during 1990-2014 at Happy Isles. Concentration-discharge (C-Q) in streamflow was dominated by a well-defined power law relation, with the magnitude of exponent (0.02-0.6) and R2 values (p diagnostic tool to understand streamflow generation and hydrochemical controls in catchment hydrologic studies.

  20. Numerical simulation of groundwater artificial recharge in a semiarid-climate basin of northwest Mexico, case study the Guadalupe Valley Aquifer, Baja California

    Science.gov (United States)

    Campos-Gaytan, J. R.; Herrera-Oliva, C. S.

    2013-05-01

    In this study was analyzed through a regional groundwater flow model the effects on groundwater levels caused by the application of different future groundwater management scenarios (2007-2025) at the Guadalupe Valley, in Baja California, Mexico. Among these studied alternatives are those scenarios designed in order to evaluate the possible effects generated for the groundwater artificial recharge in order to satisfy a future water demand with an extraction volume considered as sustainable. The State of Baja California has been subject to an increment of the agricultural, urban and industrials activities, implicating a growing water-demand. However, the State is characterized by its semiarid-climate with low surface water availability; therefore, has resulted in an extensive use of groundwater in local aquifer. Water level measurements indicate there has been a decline in water levels in the Guadalupe Valley for the past 30 years. The Guadalupe Valley aquifer represents one the major sources of water supply in Ensenada region. It supplies about 25% of the water distributed by the public water supplier at the city of Ensenada and in addition constitutes the main water resource for the local wine industries. Artificially recharging the groundwater system is one water resource option available to the study zone, in response to increasing water demand. The existing water supply system for the Guadalupe Valley and the city of Ensenada is limited since water use demand periods in 5 to 10 years or less will require the construction of additional facilities. To prepare for this short-term demand, one option available to water managers is to bring up to approximately 3.0 Mm3/year of treated water of the city of Ensenada into the valley during the low-demand winter months, artificially recharge the groundwater system, and withdraw the water to meet the summer demands. A 2- Dimensional groundwater flow was used to evaluate the effects of the groundwater artificial recharge

  1. Playing It Safe: Assessing Cumulative Impact and Social Vulnerability through an Environmental Justice Screening Method in the South Coast Air Basin, California

    Directory of Open Access Journals (Sweden)

    Justin Scoggins

    2011-05-01

    Full Text Available Regulatory agencies, including the U.S. Environmental Protection Agency (US EPA and state authorities like the California Air Resources Board (CARB, have sought to address the concerns of environmental justice (EJ advocates who argue that chemical-by-chemical and source-specific assessments of potential health risks of environmental hazards do not reflect the multiple environmental and social stressors faced by vulnerable communities. We propose an Environmental Justice Screening Method (EJSM as a relatively simple, flexible and transparent way to examine the relative rank of cumulative impacts and social vulnerability within metropolitan regions and determine environmental justice areas based on more than simply the demographics of income and race. We specifically organize 23 indicator metrics into three categories: (1 hazard proximity and land use; (2 air pollution exposure and estimated health risk; and (3 social and health vulnerability. For hazard proximity, the EJSM uses GIS analysis to create a base map by intersecting land use data with census block polygons, and calculates hazard proximity measures based on locations within various buffer distances. These proximity metrics are then summarized to the census tract level where they are combined with tract centroid-based estimates of pollution exposure and health risk and socio-economic status (SES measures. The result is a cumulative impacts (CI score for ranking neighborhoods within regions that can inform diverse stakeholders seeking to identify local areas that might need targeted regulatory strategies to address environmental justice concerns.

  2. License application approach for the California LLRW disposal facility

    International Nuclear Information System (INIS)

    Gaynor, R.K.; Romano, S.A.; Hanrahan, T.P.

    1990-01-01

    US Ecology, Inc. is the State of California's license designee to site, develop and operate a low-level radioactive waste (LLRW) disposal facility to serve member states of the Southwestern Compact. US Ecology identified a proposed site in the Ward Valley of southeastern California in March 1988. Following proposed site selection, US Ecology undertook studies required to prepare a license application. US Ecology's license application for this desert site was deemed complete for detailed regulatory review by the California Department of Health Services (DHS) in December 1989. By mutual agreement, disposal of mixed waste is not proposed pending the State of California's decision on appropriate management of this small LLRW subset

  3. Climate and hydrology of the last interglaciation (MIS 5) in Owens Basin, California: Isotopic and geochemical evidence from core OL-92

    Science.gov (United States)

    Li, H.-C.; Bischoff, J.L.; Ku, T.-L.; Zhu, Z.-Y.

    2004-01-01

    ??18O, ??13C, total organic carbon, total inorganic carbon, and acid-leachable Li, Mg and Sr concentrations on 443 samples from 32 to 83 m depth in Owens Lake core OL-92 were analyzed to study the climatic and hydrological conditions between 60 and 155 ka with a resolution of ???200 a. The multi-proxy data show that Owens Lake overflowed during wet/cold conditions of marine isotope stages (MIS) 4, 5b and 6, and was closed during the dry/warm conditions of MIS 5a, c and e. The lake partially overflowed during MIS 5d. Our age model places the MIS 4/5 boundary at ca 72.5 ka and the MIS 5/6 boundary (Termination II) at ca 140 ka, agreeing with the Devils Hole chronology. The diametrical precipitation intensities between the Great Basin (cold/wet) and eastern China (cold/dry) on Milankovitch time scales imply a climatic teleconnection across the Pacific. It also probably reflects the effect of high-latitude ice sheets on the southward shifts of both the summer monsoon frontal zone in eastern Asia and the polar jet stream in western North America during glacial periods. ?? 2003 Elsevier Ltd. All rights reserved.

  4. The three-dimensional geologic model used for the 2003 National Oil and Gas Assessment of the San Joaquin Basin Province, California: Chapter 7 in Petroleum systems and geologic assessment of oil and gas in the San Joaquin Basin Province, California

    Science.gov (United States)

    Hosford Scheirer, Allegra

    2013-01-01

    We present a three-dimensional geologic model of the San Joaquin Basin (SJB) that may be the first compilation of subsurface data spanning the entire basin. The model volume spans 200 × 90 miles, oriented along the basin axis, and extends to ~11 miles depth, for a total of more than 1 million grid nodes. This model supported the 2003 U.S. Geological Survey assessment of future additions to reserves of oil and gas in the SJB. Data sources include well-top picks from more than 3,200 wildcat and production wells, published cross sections, regional seismic grids, and fault maps. The model consists of 15 chronostratigraphic horizons ranging from the Mesozoic crystalline basement to the topographic surface. Many of the model units are hydrocarbon reservoir rocks and three—the Cretaceous Moreno Formation, the Eocene Kreyenhagen Formation, and the Miocene Monterey Formation—are hydrocarbon source rocks. The White Wolf Fault near the southern end of the basin divides the map volume into 2 separate fault blocks. The construction of a three-dimensional model of the entire SJB encountered many challenges, including complex and inconsistent stratigraphic nomenclature, significant facies changes across and along the basin axis, time-transgressive formation tops, uncertain correlation of outcrops with their subsurface equivalents, and contradictory formation top data. Although some areas of the model are better resolved than others, the model facilitated the 2003 resource assessment in several ways, including forming the basis of a petroleum system model and allowing a precise definition of assessment unit volumes.

  5. Temporal Controls on Uplift and Slip Rates for the Puente Hills and Santa Ana Mountains, Southern Los Angeles Basin, Orange County, California

    Science.gov (United States)

    Gath, E. M.; Grant, L. B.; Owen, L. A.

    2006-12-01

    The Puente Hills (PH) are seismically active and tectonically uplifted by the Puente Hills Blind Thrust fault (PHBTF). The rate of uplift, and consequently, the late Quaternary slip rate of the eastern part of the PHBTF, herein named the Santa Ana segment, can be constrained by mapping and dating Quaternary stream terraces and strath surfaces in the Santa Ana River Canyon. The PH are cut by the 2-3 mm/yr right-lateral Whittier fault, itself capable of M6.7-7.2 earthquakes. The 7 mapped terraces and strath surfaces of the PH are cut by the Whittier fault with minimal vertical separation. OSL dating, soil age estimates, and correlation with sea level highstands constrains the PH uplift rate to 0.6-1.4 mm/yr based on OSL dates, and 0.2-0.8 mm/yr from other methods. The rates overlap in the range 0.6-0.8 mm/yr, and we propose that this is the most reliable estimate of uplift rate because it is based on several methods. An uplift rate of 0.6-0.8 mm/yr for the PH is also consistent with a 500 700 ka emergent age based on our geomorphic analysis of PH drainage basin development. Using a 30° dip angle produces a slip rate on the Santa Ana segment of the PHBTF of 1.2-1.6 mm/yr. Preliminary tectonic geomorphic analysis of the Santa Ana Mountains (SAM) suggests that they too are being uplifted and are probably seismically active. Shorelines preserved on the lower foothills of Peralta and Loma Ridges were correlated to eustatic sea levels for age estimations. Mapping and dating of terraces in the Santiago Creek drainage, and the older marine terraces indicates that the SAM are uplifting at 0.2-0.7 mm/yr, probably due to a blind thrust associated with partial termination of the Elsinore fault.

  6. Saline water in southeastern New Mexico

    Science.gov (United States)

    Hiss, W.L.; Peterson, J.B.; Ramsey, T.R.

    1969-01-01

    Saline waters from formations of several geologic ages are being studied in a seven-county area in southeastern New Mexico and western Texas, where more than 30,000 oil and gas tests have been drilled in the past 40 years. This area of 7,500 sq. miles, which is stratigraphically complex, includes the northern and eastern margins of the Delaware Basin between the Guadalupe and Glass Mountains. Chloride-ion concentrations in water produced from rocks of various ages and depths have been mapped in Lea County, New Mexico, using machine map-plotting techniques and trend analyses. Anomalously low chloride concentrations (1,000-3,000 mg/l) were found along the western margin of the Central Basin platform in the San Andres and Capitan Limestone Formations of Permian age. These low chloride-ion concentrations may be due to preferential circulation of ground water through the more porous and permeable rocks. Data being used in the study were obtained principally from oil companies and from related service companies. The P.B.W.D.S. (Permian Basin Well Data System) scout-record magnetic-tape file was used as a framework in all computer operations. Shallow or non-oil-field water analyses acquired from state, municipal, or federal agencies were added to these data utilizing P.B.W.D.S.-compatible reference numbers and decimal latitude-longitude coordinates. Approximately 20,000 water analyses collected from over 65 sources were coded, recorded on punch cards and stored on magnetic tape for computer operations. Extensive manual and computer error checks for duplication and accuracy were made to eliminate data errors resulting from poorly located or identified samples; non-representative or contaminated samples; mistakes in coding, reproducing or key-punching; laboratory errors; and inconsistent reporting. The original 20,000 analyses considered were reduced to 6,000 representative analyses which are being used in the saline water studies. ?? 1969.

  7. Ophiolitic basement to the Great Valley forearc basin, California, from seismic and gravity data: Implications for crustal growth at the North American continental margin

    Science.gov (United States)

    Godfrey, N.J.; Beaudoin, B.C.; Klemperer, S.L.; Levander, A.; Luetgert, J.; Meltzer, A.; Mooney, W.; Tréhu, A.

    1997-01-01

    The nature of the Great Valley basement, whether oceanic or continental, has long been a source of controversy. A velocity model (derived from a 200-km-long east-west reflection-refraction profile collected south of the Mendocino triple junction, northern California, in 1993), further constrained by density and magnetic models, reveals an ophiolite underlying the Great Valley (Great Valley ophiolite), which in turn is underlain by a westward extension of lower-density continental crust (Sierran affinity material). We used an integrated modeling philosophy, first modeling the seismic-refraction data to obtain a final velocity model, and then modeling the long-wavelength features of the gravity data to obtain a final density model that is constrained in the upper crust by our velocity model. The crustal section of Great Valley ophiolite is 7-8 km thick, and the Great Valley ophiolite relict oceanic Moho is at 11-16 km depth. The Great Valley ophiolite does not extend west beneath the Coast Ranges, but only as far as the western margin of the Great Valley, where the 5-7-km-thick Great Valley ophiolite mantle section dips west into the present-day mantle. There are 16-18 km of lower-density Sierran affinity material beneath the Great Valley ophiolite mantle section, such that a second, deeper, "present-day" continental Moho is at about 34 km depth. At mid-crustal depths, the boundary between the eastern extent of the Great Valley ophiolite and the western extent of Sierran affinity material is a near-vertical velocity and density discontinuity about 80 km east of the western margin of the Great Valley. Our model has important implications for crustal growth at the North American continental margin. We suggest that a thick ophiolite sequence was obducted onto continental material, probably during the Jurassic Nevadan orogeny, so that the Great Valley basement is oceanic crust above oceanic mantle vertically stacked above continental crust and continental mantle.

  8. Ichthyofauna of two streams (silted and reference in the Upper Paraná river basin, Southeastern Brazil Ictiofauna de dois riachos (assoreado e referência na bacia do Alto Rio Paraná, Sudeste do Brasil

    Directory of Open Access Journals (Sweden)

    L. Casatti

    2004-11-01

    Full Text Available In this study the fish assemblages of the silted Águas Claras stream (AC was compared with that of a reference, the São Carlos stream (SC, so as to identify potential fish indicators of integrity or degradation. Both streams, located about 5 km from one another, are part of the Upper Paraná river basin, Brazil, and present similar physiographical features. Twenty-one species were collected in AC (1,271 specimens and 18 in SC (940 specimens. In AC, dominant species e.g., Corydoras aeneus (sandy pools, Serrapinnus notomelas, and Pyrrhulina australis (warm marginal shallow pools were those favored by new microhabitats linked to siltation and removal of the riparian vegetation. Changes in the composition of the marginal vegetation resulted in dominance of species such as Hisonotus francirochai (marginal grasses. In SC the dominant species was Phalloceros caudimacultus, abundant in marginal shallow pools, and Trichomycterus diabolus. and Hypostomus nigromaculatus, exclusively riffle-dwelling species, which were absent in AC. Fish assemblage monitoring is recommended for use in riparian management programs in order to evaluate negative instream sedimentation effects.Neste trabalho, a ictiofauna de um riacho assoreado (córrego Águas Claras - AC foi comparada com a de um riacho referência (córrego São Carlos - SC, com o objetivo de identificar espécies potencialmente indicadoras de integridade ou degradação. Os riachos localizam-se na bacia do Alto Rio Paraná, Brasil, estão distantes cerca de 5 km entre si e apresentam características fisiográficas semelhantes. Foram coletadas 21 espécies no AC (1.271 indivíduos e 18 no SC (940 indivíduos. No AC, as espécies dominantes foram aquelas favorecidas por microhabitats relacionados ao assoreamento e à remoção da vegetação marginal, como Corydoras aeneus (poços de fundo de areia, Serrapinnus notomelas e Pyrrhulina australis (poços rasos marginais, e por alterações na vegeta

  9. Ephemeral-stream channel and basin-floor infiltration and recharge in the Sierra Vista subwatershed of the Upper San Pedro Basin, Southeastern Arizona: Chapter J in Ground-water recharge in the arid and semiarid southwestern United States (Professional Paper 1703)

    Science.gov (United States)

    Coes, A.L.; Pool, D.R.; Stonestrom, David A.; Constantz, Jim; Ferré, Ty P.A.; Leake, Stanley A.

    2007-01-01

    The timing and location of streamflow in the San Pedro River are partially dependent on the aerial distribution of recharge in the Sierra Vista subwatershed. Previous investigators have assumed that recharge in the subwatershed occurs only along the mountain fronts by way of stream-channel infiltration near the contact between low-permeability rocks of the mountains and the basin fill. Recent studies in other alluvial basins of the Southwestern United States, however, have shown that significant recharge can occur through the sediments of ephemeral stream channels at locations several kilometers distant from the mountains. The purpose of this study was to characterize the spatial distribution of infiltration and subsequent recharge through the ephemeral channels in the Sierra Vista subwatershed.Infiltration fluxes in ephemeral channels and through the basin floor of the subwatershed were estimated by using several methods. Data collected during the drilling and coring of 16 boreholes included physical, thermal, and hydraulic properties of sediments; chloride concentrations of sediments; and pore-water stable-isotope values and tritium activity. Surface and subsurface sediment temperatures were continuously measured at each borehole.Twelve boreholes were drilled in five ephemeral stream channels to estimate infiltration within ephemeral channels. Active infiltration was verified to at least 20 meters at 11 of the 12 borehole sites on the basis of low sediment-chloride concentrations, high soil-water contents, and pore-water tritium activity similar to present-day precipitation. Consolidated sediments at the twelfth site prevented core recovery and estimation of infiltration. Analytical and numerical methods were applied to determine the surface infiltration flux required to produce the observed sediment-temperature fluctuations at six sites. Infiltration fluxes were determined for summer ephemeral flow events only because no winter flows were recorded at the sites

  10. Simulation of climate change in San Francisco Bay Basins, California: Case studies in the Russian River Valley and Santa Cruz Mountains

    Science.gov (United States)

    Flint, Lorraine E.; Flint, Alan L.

    2012-01-01

    relationship between soil moisture storage and evapotranspiration pressures, climatic water deficit integrates the effects of increasing temperature and varying precipitation on basin conditions. At the fine-scale used for these analyses, this variable is an effective indicator of the areas in the landscape that are the most resilient or vulnerable to projected changes. These analyses have shown that regardless of the direction of precipitation change, climatic water deficit is projected to increase, which implies greater water demand to maintain current agricultural resources or land cover. Fine-scale modeling provides a spatially distributed view of locations in the landscape that could prove to be resilient to climatic changes in contrast to locations where vegetation is currently living on the edge of its present-day bioclimatic distribution and, therefore, is more likely to perish or shift to other dominant species under future warming. This type of modeling and the associated analyses provide a useful means for greater understanding of water and land resources, which can lead to better resource management and planning.

  11. 76 FR 3655 - Bunker Hill Groundwater Basin, Riverside-Corona Feeder Project, San Bernardino and Riverside...

    Science.gov (United States)

    2011-01-20

    ... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Bunker Hill Groundwater Basin, Riverside-Corona... imported water supplies, using available capacity in the Bunker Hill Groundwater Basin and the Chino Basin... groundwater wells in the Bunker Hill Groundwater Basin, San Bernardino County, California. Existing recharge...

  12. Groundwater-quality data in the Borrego Valley, Central Desert, and Low-Use Basins of the Mojave and Sonoran Deserts study unit, 2008-2010--Results from the California GAMA Program

    Science.gov (United States)

    Mathany, Timothy M.; Wright, Michael T.; Beuttel, Brandon S.; Belitz, Kenneth

    2012-01-01

    Groundwater quality in the 12,103-square-mile Borrego Valley, Central Desert, and Low-Use Basins of the Mojave and Sonoran Deserts (CLUB) study unit was investigated by the U.S. Geological Survey (USGS) from December 2008 to March 2010, as part of the California State Water Resources Control Board (SWRCB) Groundwater Ambient Monitoring and Assessment (GAMA) Program's Priority Basin Project (PBP). The GAMA-PBP was developed in response to the California Groundwater Quality Monitoring Act of 2001 and is being conducted in collaboration with the SWRCB and Lawrence Livermore National Laboratory (LLNL). The CLUB study unit was the twenty-eighth study unit to be sampled as part of the GAMA-PBP. The GAMA CLUB study was designed to provide a spatially unbiased assessment of untreated-groundwater quality in the primary aquifer systems, and to facilitate statistically consistent comparisons of untreated-groundwater quality throughout California. The primary aquifer systems (hereinafter referred to as primary aquifers) are defined as parts of aquifers corresponding to the perforation intervals of wells listed in the California Department of Public Health (CDPH) database for the CLUB study unit. The quality of groundwater in shallow or deep water-bearing zones may differ from the quality of groundwater in the primary aquifers; shallow groundwater may be more vulnerable to surficial contamination. In the CLUB study unit, groundwater samples were collected from 52 wells in 3 study areas (Borrego Valley, Central Desert, and Low-Use Basins of the Mojave and Sonoran Deserts) in San Bernardino, Riverside, Kern, San Diego, and Imperial Counties. Forty-nine of the wells were selected by using a spatially distributed, randomized grid-based method to provide statistical representation of the study unit (grid wells), and three wells were selected to aid in evaluation of water-quality issues (understanding wells). The groundwater samples were analyzed for organic constituents (volatile

  13. Mid-to-Late Holocene Hydrologic Variability in the Southeastern Mojave Desert Using Sediments from Ford Lake

    Science.gov (United States)

    Mayer, S. A.; Kirby, M. E.; Anderson, W. T., Jr.; Stout, C.; Palermo, J. A.

    2015-12-01

    The focal point of most lacustrine studies in the Mojave National Preserve (MNP) to date has been on lakes fed by the Mojave River. The source of the Mojave River is found on the northern flank of the San Bernardino Mountains. Consequently, the lakes that receive these waters are predominantly responding to the winter-only coastal southwest United States climate (e.g., Kirby et al., 2015 - Silver Lake); to a lesser degree, these lakes are also influenced by the Mojave's bimodal winter/summer climate. Ford Lake, located in the southeastern Mojave Desert is a small closed basin lake with its drainage basin located exclusively within the Mojave Desert. Therefore, sediment collected from Ford Lake contains a 100% Mojave-only climate signal. A 2.18 m sediment core was collected from the lake's depocenter in May 2015. Sediment analyses at 1 cm contiguous intervals include: magnetic susceptibility (MS), percent total organic matter, percent total carbonate content, and grain size analysis; C:N ratios, C and N isotope (δ13C and δ15N) analyses, and macrofossil counts are determined at 2 cm intervals. The site's age model is based on accelerator mass spectrometry (AMS) radiocarbon ages from discrete organic macrofossils or bulk organic carbon. To deconvolve the coastal climate, winter-only signal from the Mojave-only climate signal the data from Ford Lake will be compared to one Mojave River fed lake (Silver) and several southern California lakes (Lower Bear, Lake Elsinore, Dry Lake, and Zaca Lake). Our results will be analyzed in the context of climate forcings such as insolation and ocean - atmosphere dynamics.

  14. The changing hydroclimatology of Southeastern U.S.

    Science.gov (United States)

    Engström, Johanna; Waylen, Peter

    2017-05-01

    The allocation of the water resources of Southeastern United States have given rise to inter-state political conflicts for decades. The limited water resource are not only required to satisfy the demand of rapidly growing urban areas, but also the power industry, recreational needs and the environment. Although water resource variability has been attributed to various teleconnections, knowledge of long-term water resource availability is limited. In this paper historical (1952-2014) precipitation and streamflow data from 18 basins in southeast United States are analyzed for long-term changes in the hydroclimatology, possibly brought by urbanization, climate change and/or changed precipitation patterns. A Pettitt test indicates a change in the precipitation-runoff relationship in the late 1990s. After the shift, basin records indicate decreased precipitation storage and consequently increased streamflow.

  15. Groundwater-quality data in seven GAMA study units: results from initial sampling, 2004-2005, and resampling, 2007-2008, of wells: California GAMA Program Priority Basin Project

    Science.gov (United States)

    Kent, Robert; Belitz, Kenneth; Fram, Miranda S.

    2014-01-01

    The Priority Basin Project (PBP) of the Groundwater Ambient Monitoring and Assessment (GAMA) Program was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The GAMA-PBP began sampling, primarily public supply wells in May 2004. By the end of February 2006, seven (of what would eventually be 35) study units had been sampled over a wide area of the State. Selected wells in these first seven study units were resampled for water quality from August 2007 to November 2008 as part of an assessment of temporal trends in water quality by the GAMA-PBP. The initial sampling was designed to provide a spatially unbiased assessment of the quality of raw groundwater used for public water supplies within the seven study units. In the 7 study units, 462 wells were selected by using a spatially distributed, randomized grid-based method to provide statistical representation of the study area. Wells selected this way are referred to as grid wells or status wells. Approximately 3 years after the initial sampling, 55 of these previously sampled status wells (approximately 10 percent in each study unit) were randomly selected for resampling. The seven resampled study units, the total number of status wells sampled for each study unit, and the number of these wells resampled for trends are as follows, in chronological order of sampling: San Diego Drainages (53 status wells, 7 trend wells), North San Francisco Bay (84, 10), Northern San Joaquin Basin (51, 5), Southern Sacramento Valley (67, 7), San Fernando–San Gabriel (35, 6), Monterey Bay and Salinas Valley Basins (91, 11), and Southeast San Joaquin Valley (83, 9). The groundwater samples were analyzed for a large number of synthetic organic constituents (volatile organic compounds [VOCs], pesticides, and pesticide degradates), constituents of special interest (perchlorate, N

  16. An Overview of Geologic Carbon Sequestration Potential in California

    Energy Technology Data Exchange (ETDEWEB)

    Cameron Downey; John Clinkenbeard

    2005-10-01

    As part of the West Coast Regional Carbon Sequestration Partnership (WESTCARB), the California Geological Survey (CGS) conducted an assessment of geologic carbon sequestration potential in California. An inventory of sedimentary basins was screened for preliminary suitability for carbon sequestration. Criteria included porous and permeable strata, seals, and depth sufficient for critical state carbon dioxide (CO{sub 2}) injection. Of 104 basins inventoried, 27 met the criteria for further assessment. Petrophysical and fluid data from oil and gas reservoirs was used to characterize both saline aquifers and hydrocarbon reservoirs. Where available, well log or geophysical information was used to prepare basin-wide maps showing depth-to-basement and gross sand distribution. California's Cenozoic marine basins were determined to possess the most potential for geologic sequestration. These basins contain thick sedimentary sections, multiple saline aquifers and oil and gas reservoirs, widespread shale seals, and significant petrophysical data from oil and gas operations. Potential sequestration areas include the San Joaquin, Sacramento, Ventura, Los Angeles, and Eel River basins, followed by the smaller Salinas, La Honda, Cuyama, Livermore, Orinda, and Sonoma marine basins. California's terrestrial basins are generally too shallow for carbon sequestration. However, the Salton Trough and several smaller basins may offer opportunities for localized carbon sequestration.

  17. Suicide in Batman, Southeastern Turkey

    Science.gov (United States)

    Altindag, Abdurrahman; Ozkan, Mustafa; Oto, Remzi

    2005-01-01

    The southeastern part of Turkey has comparatively high female suicide rates. We aimed to research social, economic, cultural, and psychiatric reasons of suicides in Batman in a case-controlled psychological autopsy study comparing suicides with matched community controls. The female suicide rate was 9.3 per 100.000 and the female/male ratio was…

  18. Towards an improved understanding of hillslope runoff as a supply for groundwater recharge: Assessing hillslope runoff under regional deforestation and varying climate conditions in a drainage basin in central coastal California

    Science.gov (United States)

    Young, K. S.; Beganskas, S.; Fisher, A. T.

    2017-12-01

    We use a hydrologic model to analyze hillslope runoff under a range of climate and land use conditions in the San Lorenzo River Basin (SLRB), central coastal California, including contemporary land use and incremental deforestation. The SLRB is a heavily forested watershed with chronically overdrafted aquifers; in some areas, groundwater levels have been lowered by >50 m in recent decades. Managed aquifer recharge (MAR) can help mitigate declines in groundwater storage, routing excess surface flows to locations where they can infiltrate. We are especially interested in opportunities for collection of stormwater runoff, particularly where development and other changes in landuse have increased hill slope runoff. To assess hillslope runoff at the subwatershed scale (10-100 ha; 25-250 ac), we apply the Precipitation Runoff Modeling System (PRMS) to a high-resolution, digital elevation model and populate the simulation with area- and density-weighted vegetation and soil parameters calculated from high resolution input data. We also develop and apply a catalog of dry, normal, and wet climate scenarios from the historic record (1981-2014). In addition, we simulate conditions ranging from 0 to 100 percent of redwoods harvested (representing the mid-1800s to 1930s logging era) using a historical land use data set to alter soil and vegetation conditions. Results under contemporary land use suggest there are ample opportunities to establish MAR projects during all climate scenarios; hill slope runoff generation is spatially variable and on average exceeds 23,000 ac-ft/yr (3.2 in/yr) during the driest climate scenario. Preliminary results from the deforestation scenarios show notable increases in hillslope runoff with progressive redwood harvesting. Relative to pre-logging conditions, between 1.1 in (dry climates) and 1.5 in (wet climates) more runoff is generated under contemporary conditions, with most of the runoff increase occurring in urban areas. These modeling methods

  19. Mercury, methylmercury, and other constituents in sediment and water from seasonal and permanent wetlands in the Cache Creek settling basin and Yolo Bypass, Yolo County, California, 2005-06

    Science.gov (United States)

    Marvin-DiPasquale, Mark; Alpers, Charles N.; Fleck, Jacob A.

    2009-01-01

    This report presents surface water and surface (top 0-2 cm) sediment geochemical data collected during 2005-2006, as part of a larger study of mercury (Hg) dynamics in seasonal and permanently flooded wetland habitats within the lower Sacramento River basin, Yolo County, California. The study was conducted in two phases. Phase I represented reconnaissance sampling and included three locations within the Cache Creek drainage basin; two within the Cache Creek Nature Preserve (CCNP) and one in the Cache Creek Settling Basin (CCSB) within the creek's main channel near the southeast outlet to the Yolo Bypass. Two additional downstream sites within the Yolo Bypass Wildlife Area (YBWA) were also sampled during Phase I, including one permanently flooded wetland and one seasonally flooded wetland, which had began being flooded only 1–2 days before Phase I sampling.Results from Phase I include: (a) a negative correlation between total mercury (THg) and the percentage of methylmercury (MeHg) in unfiltered surface water; (b) a positive correlation between sediment THg concentration and sediment organic content; (c) surface water and sediment THg concentrations were highest at the CCSB site; (d) sediment inorganic reactive mercury (Hg(II)R) concentration was positively related to sediment oxidation-reduction potential and negatively related to sediment acid volatile sulfur (AVS) concentration; (e) sediment Hg(II)R concentrations were highest at the two YBWA sites; (f) unfiltered surface water MeHg concentration was highest at the seasonal wetland YBWA site, and sediment MeHg was highest at the permanently flooded YBWA site; (g) a 1,000-fold increase in sediment pore water sulfate concentration was observed in the downstream transect from the CCNP to the YBWA; (h) low sediment pore water sulfide concentrations (towards the end of the seasonal flooding period (end of May 2006). Results from Phase II sampling include: (a) sediment MeHg concentration and the percentage of THg as

  20. New TNX Seepage Basin: Environmental information document

    International Nuclear Information System (INIS)

    Dunaway, J.K.W.; Johnson, W.F.; Kingley, L.E.; Simmons, R.V.; Bledsoe, H.W.

    1986-12-01

    The New TNX Seepage Basin has been in operation at the Savannah River Plant (SRP) since 1980 and is located in the southeastern section of the TNX facility. The basin receives waste from pilot scale tests conducted at TNX in support of the Defense Waste Processing Facility (DWPF) and the plant Separations area. The basin is scheduled for closure after the TNX Effluent Treatment Plant (ETP) begins operation. The basin will be closed pursuant to all applicable state and federal regulations. A statistical analysis of monitoring data indicates elevated levels of sodium and zinc in the groundwater at this site. Closure options considered for the New TNX Seepage Basin include waste removal and closure, no waste removal and closure, and no action. The two predominant pathways for human exposure to chemical contaminants are through surface, subsurface, and atmospheric transport. Modeling calculations were made to determine the risks to human population via these general pathways for the three postulated closure options for the New TNX Seepage Basin. Cost estimates for each closure option at the basin have also been prepared. An evaluation of the environmental impacts from the New TNX Seepage Basin indicate that the relative risks to human health and ecosystems for the postulated closure options are low. The transport of six chemical and one radionuclide constituents through the environmental pathways from the basin were modeled. The maximum chemical carcinogenic risk and the noncarcinogenic risk for the groundwater pathways were from exposure to trichloromethane and nitrate

  1. California's experience with alternative fuel vehicles

    International Nuclear Information System (INIS)

    Sullivan, C.

    1993-01-01

    California is often referred to as a nation-state, and in many aspects fits that description. The state represents the seventh largest economy in the world. Most of California does not have to worry about fuel to heat homes in the winter. What we do worry about is fuel for our motor vehicles, approximately 24 million of them. In fact, California accounts for ten percent of new vehicle sales in the United States each year, much of it used in the transportation sector. The state is the third largest consumer of gasoline in the world, only exceeded by the United States as a whole and the former Soviet Union. California is also a leader in air pollution. Of the nine worst ozone areas in the country cited in the 1990 Clean Air Act Amendments, two areas the Los Angeles Basin and San Diego are located in California. Five of California's cities made the top 20 smoggiest cities in the United States. In reality, all of California's major metropolitan areas have air quality problems. This paper will discuss the beginnings of California's investigations of alternative fuels use in vehicles; the results of the state's demonstration programs; and future plans to improve California's air quality and energy security in the mobile sector

  2. A new species of Contulma Flint (Trichoptera, Anomalopsychidae from southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Gabriela A. Jardim

    2011-06-01

    Full Text Available A new species of Contulma Flint (Trichoptera, Anomalopsychidae from southeastern Brazil. Contulma sana sp. nov. is described and illustrated based on specimens collected in the Rio Macaé Basin, Macaé, Rio de Janeiro State, Brazil. The new species can be distinguished from congeners by the following male genitalia characters: long posterior lobes, dorsomedian processes of segment IX diverging on apical third, and well developed phallotremal sclerite. The female and immature stages are unknown.

  3. Use of Cutting-Edge Horizontal and Underbalanced Drilling Technologies and Subsurface Seismic Techniques to Explore, Drill and Produce Reservoired Oil and Gas from the Fractured Monterey Below 10,000 ft in the Santa Maria Basin of California

    Energy Technology Data Exchange (ETDEWEB)

    George Witter; Robert Knoll; William Rehm; Thomas Williams

    2006-06-30

    This project was undertaken to demonstrate that oil and gas can be drilled and produced safely and economically from a fractured Monterey reservoir in the Santa Maria Basin of California by employing horizontal wellbores and underbalanced drilling technologies. Two vertical wells were previously drilled in this area with heavy mud and conventional completions; neither was commercially productive. A new well was drilled by the project team in 2004 with the objective of accessing an extended length of oil-bearing, high-resistivity Monterey shale via a horizontal wellbore, while implementing managed-pressure drilling (MPD) techniques to avoid formation damage. Initial project meetings were conducted in October 2003. The team confirmed that the demonstration well would be completed open-hole to minimize productivity impairment. Following an overview of the geologic setting and local field experience, critical aspects of the application were identified. At the pre-spud meeting in January 2004, the final well design was confirmed and the well programming/service company requirements assigned. Various design elements were reduced in scope due to significant budgetary constraints. Major alterations to the original plan included: (1) a VSP seismic survey was delayed to a later phase; (2) a new (larger) surface hole would be drilled rather than re-enter an existing well; (3) a 7-in. liner would be placed into the top of the Monterey target as quickly as possible to avoid problems with hole stability; (4) evaluation activities were reduced in scope; (5) geosteering observations for fracture access would be deduced from penetration rate, cuttings description and hydrocarbon in-flow; and (6) rather than use nitrogen, a novel air-injection MPD system was to be implemented. Drilling operations, delayed from the original schedule by capital constraints and lack of rig availability, were conducted from September 12 to November 11, 2004. The vertical and upper curved sections were

  4. USE OF CUTTING-EDGE HORIZONTAL AND UNDERBALANCED DRILLING TECHNOLOGIES AND SUBSURFACE SEISMIC TECHNIQUES TO EXPLORE, DRILL AND PRODUCE RESERVOIRED OIL AND GAS FROM THE FRACTURED MONTEREY BELOW 10,000 FT IN THE SANTA MARIA BASIN OF CALIFORNIA

    Energy Technology Data Exchange (ETDEWEB)

    George Witter; Robert Knoll; William Rehm; Thomas Williams

    2005-02-01

    This project was undertaken to demonstrate that oil and gas can be drilled and produced safely and economically from a fractured Monterey reservoir in the Santa Maria Basin of California by employing horizontal wellbores and underbalanced drilling technologies. Two vertical wells were previously drilled in this area by Temblor Petroleum with heavy mud and conventional completions; neither was commercially productive. A new well was drilled by the project team in 2004 with the objective of accessing an extended length of oil-bearing, high-resistivity Monterey shale via a horizontal wellbore, while implementing managed-pressure drilling (MPD) techniques to avoid formation damage. Initial project meetings were conducted in October 2003. The team confirmed that the demonstration well would be completed open-hole to minimize productivity impairment. Following an overview of the geologic setting and local field experience, critical aspects of the application were identified. At the pre-spud meeting in January 2004, the final well design was confirmed and the well programming/service company requirements assigned. Various design elements were reduced in scope due to significant budgetary constraints. Major alterations to the original plan included: (1) a VSP seismic survey was delayed to a later phase; (2) a new (larger) surface hole would be drilled rather than re-enter an existing well; (3) a 7-in. liner would be placed into the top of the Monterey target as quickly as possible to avoid problems with hole stability; (4) evaluation activities were reduced in scope; (5) geosteering observations for fracture access would be deduced from penetration rate, cuttings description and hydrocarbon in-flow; and (6) rather than use nitrogen, a novel air-injection MPD system was to be implemented. Drilling operations, delayed from the original schedule by capital constraints and lack of rig availability, were conducted from September 12 to November 11, 2004. The vertical and upper

  5. Use of Cutting-Edge Horizontal and Underbalanced Drilling Technologies and Subsurface Seismic Techniques to Explore, Drill and Produce Reservoired Oil and Gas from the Fractured Monterey Below 10,000 ft in the Santa Maria Basin of California

    Energy Technology Data Exchange (ETDEWEB)

    George Witter; Robert Knoll; William Rehm; Thomas Williams

    2005-09-29

    This project was undertaken to demonstrate that oil and gas can be drilled and produced safely and economically from a fractured Monterey reservoir in the Santa Maria Basin of California by employing horizontal wellbores and underbalanced drilling technologies. Two vertical wells were previously drilled in this area with heavy mud and conventional completions; neither was commercially productive. A new well was drilled by the project team in 2004 with the objective of accessing an extended length of oil-bearing, high-resistivity Monterey shale via a horizontal wellbore, while implementing managed-pressure drilling (MPD) techniques to avoid formation damage. Initial project meetings were conducted in October 2003. The team confirmed that the demonstration well would be completed open-hole to minimize productivity impairment. Following an overview of the geologic setting and local field experience, critical aspects of the application were identified. At the pre-spud meeting in January 2004, the final well design was confirmed and the well programming/service company requirements assigned. Various design elements were reduced in scope due to significant budgetary constraints. Major alterations to the original plan included: (1) a VSP seismic survey was delayed to a later phase; (2) a new (larger) surface hole would be drilled rather than re-enter an existing well; (3) a 7-in. liner would be placed into the top of the Monterey target as quickly as possible to avoid problems with hole stability; (4) evaluation activities were reduced in scope; (5) geosteering observations for fracture access would be deduced from penetration rate, cuttings description and hydrocarbon in-flow; and (6) rather than use nitrogen, a novel air-injection MPD system was to be implemented. Drilling operations, delayed from the original schedule by capital constraints and lack of rig availability, were conducted from September 12 to November 11, 2004. The vertical and upper curved sections were

  6. Dusty Skies over Southern California

    Science.gov (United States)

    2002-01-01

    Southern California's 'Santa Anas' are dry, north-easterly winds having speeds in excess of 25 knots (46 kilometers/hour). Santa Ana conditions are commonly associated with gusts of more than twice this level. These offshore winds usually occur in late fall and winter when a high pressure system forms in the Great Basin between the Sierra Nevadas and the Rocky Mountains. The air warms as it flows downslope from the high plateau, and its speed increases dramatically when forced through narrow canyons and mountain passes. Due to Southern California's uneven terrain, the strength of the winds varies greatly from place to place, and the Santa Anas can be sufficiently strong to pick up surface dust.This view from the Multi-angle Imaging SpectroRadiometer shows the pattern of airborne dust stirred up by Santa Ana winds on February 9, 2002. The image is from MISR's 70-degree forward-viewing camera, and airborne particulates are especially visible due to the camera's oblique viewing angle. Southeast of the Los Angeles Basin, a swirl of dust, probably blown through the Banning Pass, curves toward the ocean near Dana Point. The largest dust cloud occurs near Ensenada, in Baja California, Mexico. Also visible in this image is a blue-gray smoke plume from a small fire located near the southern flank of Palomar Mountain in Southern California.This image was acquired during Terra orbit 11423, and represents an area of about 410 kilometers x 511 kilometers.MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

  7. Groundwater-quality data in 12 GAMA study units: Results from the 2006–10 initial sampling period and the 2008–13 trend sampling period, California GAMA Priority Basin Project

    Science.gov (United States)

    Mathany, Timothy M.

    2017-03-09

    The Priority Basin Project (PBP) of the Groundwater Ambient Monitoring and Assessment (GAMA) program was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey in cooperation with the California State Water Resources Control Board. From 2004 through 2012, the GAMA-PBP collected samples and assessed the quality of groundwater resources that supply public drinking water in 35 study units across the State. Selected sites in each study unit were sampled again approximately 3 years after initial sampling as part of an assessment of temporal trends in water quality by the GAMA-PBP. Twelve of the study units, initially sampled during 2006–11 (initial sampling period) and sampled a second time during 2008–13 (trend sampling period) to assess temporal trends, are the subject of this report.The initial sampling was designed to provide a spatially unbiased assessment of the quality of untreated groundwater used for public water supplies in the 12 study units. In these study units, 550 sampling sites were selected by using a spatially distributed, randomized, grid-based method to provide spatially unbiased representation of the areas assessed (grid sites, also called “status sites”). After the initial sampling period, 76 of the previously sampled status sites (approximately 10 percent in each study unit) were randomly selected for trend sampling (“trend sites”). The 12 study units sampled both during the initial sampling and during the trend sampling period were distributed among 6 hydrogeologic provinces: Coastal (Northern and Southern), Transverse Ranges and Selected Peninsular Ranges, Klamath, Modoc Plateau and Cascades, and Sierra Nevada Hydrogeologic Provinces. For the purposes of this trend report, the six hydrogeologic provinces were grouped into two hydrogeologic regions based on location: Coastal and Mountain.The groundwater samples were analyzed for a number of synthetic organic

  8. (Dahomey) Basin

    African Journals Online (AJOL)

    Timothy Ademakinwa

    13 km maximum width in the onshore at the basin axis along Nigerian and Republic of Benin boundary. This narrows westwards and eastwards to about 5 km (Coker and Ejedawe, 1987; Coker,. 2002). Detailed geology, evolution, stratigraphy and hydrocarbon occurrence of the basin have been described by Jones and ...

  9. Relationships between basin architecture, basin closure, and occurrence of sulphide-bearing schists

    DEFF Research Database (Denmark)

    Kalliomäki, Henrik; Torvela, Taija; Moreau, Julien

    2014-01-01

    We present field observations from the Palaeoproterozoic volcano-sedimentary Tampere palaeobasin, where the primary structures have been exceptionally well preserved. We use the observations to construct a new tectonic model for the southeastern margin of the Tampere basin during its inversion...... and subsequent closure. The observed volcano-sedimentary and structural features suggest a change in the local structural style from thick-skinned inversion to thin-skinned thrusting, in order to accommodate the crustal shortening during basin closure. Furthermore, it is suggested that there is a genetic...

  10. Plio-Quaternary detrital Be-10 paleo-erosion rates from the eastern Peninsular Ranges, California

    Science.gov (United States)

    Oskin, M. E.; Le, K.; Dorsey, R. J.; Housen, B. A.; Peryam, T.

    2008-12-01

    Ancient erosion-rate records from cosmogenically produced 10Be in quartz-bearing sediments have potential to establish linkages between erosion, climate change, and tectonics. However it is challenging to isolate an erosion rate signal from subsequent 10Be ingrowth during burial and exhumation of sediments. We present preliminary 10Be erosion rates from sediments as old as 3 Ma from the Fish Creek-Vallecito basin (FCVB) in southeastern California. This basin subsided in the hanging wall of the West Salton Detachment fault, undergoing rapid sedimentation at ≥600 m/Myr until 0.95 Ma. After this time, sedimentation ceased and the basin underwent even more rapid uplift and erosion in response to mid- to late Quaternary transpression. High concentrations (~105 atoms/g) of 10Be in the sediments archived in this basin largely record slow erosion rates in upland sediment source areas in the adjacent eastern Peninsular Ranges. High-resolution magnetostratigraphy provides the necessary age control to correct 10Be for radioactive decay. These corrected concentrations indicate an approximately 40% decline in catchment-averaged erosion rate from Late Pliocene to early Pleistocene time, decreasing from 55 ± 12 m/Myr at ~2.7 Ma to 34 ± 6 m/Myr at ~1.2 Ma. 10Be-derived erosion rate from modern sediments, 31 ± 4 m/Myr, is consistent with this overall trend. Tectonic forcing of erosion rates through growth of footwall relief across the West Salton Detachment fault should yield an increase in catchment-averaged erosion rate with time, a prediction opposite of the observed trend. Thus we hypothesize that the 10Be data set may record the progressive decay of erosion rate in the source following an initial, as-yet undocumented increase due to climate forcing. Such an increase could have been forced by enhanced climate variability following the onset of northern hemisphere glaciation at ~2.5-3 Ma. Alternatively, erosion rates may have slowed as a result of gradual uplift and

  11. Malaria in prehistoric southeastern Asia.

    Science.gov (United States)

    Poolsuwan, S

    1995-03-01

    This paper reviews the evolutionary and natural history of malarias; it is proposed that all human malarial parasites originated from zoonotic simian plasmodiids in tropical forests of southeastern Asia, during the terminal Pleistocene or early Holocene. The modes of malarial transmission among prehistoric natives of that geographic area is reconstructed, based primarily on ecological, archeological and ethnographic evidence. Early Holocene hunters and food gatherers of southeastern Asia shared the same forest habitats as several mosquito members of the Anopheles leucosphyrus group, known to be efficient malarial vectors. These forest dwellers could have maintained endemic malaria, however at low levels due to their low population density. With the abundance and interactive roles in transmitting human malaria of the An. dirus and An. minimus mosquitos in forest fringe areas, the middle Holocene settled farmers occupying such habitats would have been subject all year round to highly endemic malaria. Generally much lower and less uniform transmission of the disease could have been found among early coastal occupants, in the presence of the less efficient An. sundaicus vector. Malaria was practically absent on lowland floodplains, extensively occupied by human populations since the first millennium BC onwards, due to lack of major vectors.

  12. Peculiarities of distribution of oil polution in the Southeastern Baltic by satellite data and in situ measurements

    Science.gov (United States)

    Bulycheva, E. V.; Krek, A. V.; Kostianoy, A. G.

    2016-01-01

    The results of satellite monitoring of oil pollution of the sea surface and field measurements of the concentration of oil products in the water column and bottom sediments for the first time allowed the establishment of a relation between the surface pollution from ships and the general characteristics of spatial and temporal distribution of oil products in the Southeastern Baltic Sea. Areas with increased concentrations of oil products in the surface and bottom layers were determined in the southeastern Baltic Sea. The basic directions of pollution spread, which are consistent with the main direction of annual mean transport of substances in the Gdansk Basin, are determined.

  13. Transports on the Shelf of the Southeastern Bering Sea

    Science.gov (United States)

    Righi, D. D.; Stabeno, P. J.; Hermann, A. J.

    2002-12-01

    The eastern half of the Bering Sea basin is composed of a wide (>500 kilometer) continental shelf (supply of nutrient rich shelf slope water and high solar radiation values combine to make this shelf one of the most productive regions of the world's oceans, supporting a large food chain of marine mammals, birds, fish and shellfish. An important component of the water that flows onto the eastern Bering shelf is transported through Unimak Pass. Unimak Pass (relatively shallow, transport there. To track the fate of water entering the southeastern Bering Sea through Unimak Pass, we will present simulated drifter trajectories from a regional circulation model of the northeastern Pacific and Bering Sea. These simulated trajectories will be compared with the large data set of real drifters that have been released in the Bering Sea. We will also compare transport results to hydrographic data collected along transects off Unimak Island, Port Moller, Cape Newenham and Nunivak Island.

  14. Evaluation of volatile organic compound (VOC) blank data and application of study reporting levels to groundwater data collected for the California GAMA Priority Basin Project, May 2004 through September 2010

    Science.gov (United States)

    Fram, Miranda S.; Olsen, Lisa D.; Belitz, Kenneth

    2012-01-01

    Volatile organic compounds (VOCs) were analyzed in quality-control samples collected for the California Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Project. From May 2004 through September 2010, a total of 2,026 groundwater samples, 211 field blanks, and 109 source-solution blanks were collected and analyzed for concentrations of 85 VOCs. Results from analyses of these field and source-solution blanks and of 2,411 laboratory instrument blanks during the same time period were used to assess the quality of data for the 2,026 groundwater samples. Eighteen VOCs were detected in field blanks or source-solution blanks: acetone, benzene, bromodichloromethane, 2-butanone, carbon disulfide, chloroform, 1,1-dichloroethene, dichloromethane, ethylbenzene, tetrachloroethene, styrene, tetrahydrofuran, toluene, trichloroethene, trichlorofluoromethane, 1,2,4-trimethylbenzene, m- and p-xylenes, and o-xylene. The objective of the evaluation of the VOC-blank data was to determine if study reporting levels (SRLs) were needed for any of the VOCs detected in blanks to ensure the quality of the data from groundwater samples. An SRL is equivalent to a raised reporting level that is used in place of the reporting level used by the analyzing laboratory [long‑term method detection level (LT-MDL) or laboratory reporting level (LRL)] to reduce the probability of reporting false-positive detections. Evaluation of VOC-blank data was done in three stages: (1) identification of a set of representative quality‑control field blanks (QCFBs) to be used for calculation of SRLs and identification of VOCs amenable to the SRL approach, (2) evaluation of potential sources of contamination to blanks and groundwater samples by VOCs detected in field blanks, and (3) selection of appropriate SRLs from among four potential SRLs for VOCs detected in field blanks and application of those SRLs to the groundwater data. An important conclusion from this study is that to ensure the

  15. California Political Districts

    Data.gov (United States)

    California Department of Resources — This is a series of district layers pertaining to California'spolitical districts, that are derived from the California State Senateand State Assembly information....

  16. California Political Districts

    Data.gov (United States)

    California Natural Resource Agency — This is a series of district layers pertaining to California'spolitical districts, that are derived from the California State Senateand State Assembly information....

  17. Drought and Burn Scars in Southeastern Australia

    Science.gov (United States)

    2003-01-01

    More than 2 million acres were consumed by hundreds of fires between December 2002 and February 2003 in southeastern Australia's national parks, forests, foothills and city suburbs. These images were acquired on February 14, 2002 (left) and February 17, 2003 (right) by the Multi-angle Imaging SpectroRadiometer (MISR) instrument onboard NASA's Terra satellite. The year 2002 was one of Australia's hottest and driest on record, and the acreage burnt during the summer 2002-2003 fire season in Victoria, the Australian Capital Territory and southern New South Wales, is the largest since 1938-1939, when more than 3 million acres were scorched.The extent of the burnt area and the dry conditions as of February 2003 are indicated by these contrasting false-color views. Both image panels display data from the near-infrared, red and blue spectral bands of MISR's downward-viewing (nadir) camera, as red, green and blue, respectively. This display technique causes healthy vegetation to appear red and burnt areas to show as dark brown. The data displayed from the two dates were processed identically to preserve relative brightness variations. Vegetation changes related to the dry conditions (not related to the brown burn scars) are also indicated in the February 2003 panel, where many previously red areas exhibit instead the pale yellow-brown of the underlying soils and geology. Significant reduction in the surface area of several large and important water bodies are also apparent. The diminished extent of Lake Hume (along the left-hand edge) in the later date provides a good example.The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. These data products were generated from a portion of the imagery acquired during Terra orbits 14999 and 16858. The panels cover an area of about 208 kilometers x 286 kilometers, and utilize data from blocks 118 to 121 within

  18. WATER TEMPERATURE, SALINITY, and HYDROSTATIC PRESSURE collected from R/V Point Sur in Entrance to the Gulf of California from 2013-04-19 to 2013-05-02 (NCEI Accession 0131072)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hydrographic data were collected in Pescadero Basin (at the entrance to the Gulf of California) and subsequently along the West Coast of Baja California and Southern...

  19. Southeastern superpave center pooled-fund activities.

    Science.gov (United States)

    2010-02-01

    Much has been learned about materials characteristics, testing procedures, new equipment, mix design, and pavement performance through the many studies conducted as a part of the Southeastern Superpave Center (SSC) pooled-fund program. Lessons learne...

  20. CMS: CO2 Signals Estimated for Fossil Fuel Emissions and Biosphere Flux, California

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides estimated CO2 emission signals for 16 regions (air quality basins) in California, USA, during the individual months of November 2010 and May...

  1. The availability of local aerial photography in southern California. [for solution of urban planning problems

    Science.gov (United States)

    Allen, W., III; Sledge, B.; Paul, C. K.; Landini, A. J.

    1974-01-01

    Some of the major photography and photogrammetric suppliers and users located in Southern California are listed. Recent trends in aerial photographic coverage of the Los Angeles basin area are also noted, as well as the uses of that imagery.

  2. Stable-isotope studies of groundwaters in southeastern New Mexico

    International Nuclear Information System (INIS)

    Lambert, S.J.

    1987-01-01

    Oxygen-18/16 and deuterium/hydrogen ratio measurements have been made on groundwaters sampled according to specific field criteria applied during pump tests of the Rustler Formation in Nash Draw, a solution-subsidence valley west of the WIPP site in the northern Delaware Basin of southeastern New Mexico. Comparison of these data with similar measurements on other groundwaters from the northern Delaware Basin indicates two nonoverlapping populations of meteoric groundwaters. Most of the Rustler waters in Nash Draw and at the WIPP site and older waters from the eastern two-thirds of the Capitan Limestone constitute one population, while unconfined groundwaters originating as observable modern surface recharge to alluvium, the near-surface Rustler in southwestern Nash Draw, and the Capitan in the Guadalupe Mountains (Carlsbad Caverns) constitute the other. The isotopic distinction suggests that Rustler groundwater in most of Nash Draw and at the WIPP site is not receiving significant modern meteoric recharge. A likely explanation for this distinction is that meteoric recharge to most of the Rustler and Capitan took place in the geologic past under climatic conditions significantly different from the present. 25 refs., 4 figs., 2 tabs

  3. Review of potential host rocks for radioactive waste disposal in the southeastern United States. Executive summary

    International Nuclear Information System (INIS)

    Bledsoe, H.W. Jr.; Marine, I.W.

    1980-10-01

    The geology of the southeastern United States was studied to recommend areas that should be considered for field exploration in order to select a site for a radioactive waste repository. The region studied included the Piedmont Province, the Triassic Basins, and the Atlantic Coastal Plain in Maryland, Virginia, North Carolina, South Carolina, and Georgia. This study was entirely a review of literature and existing knowledge from a geotechnical point of view and was performed by subcontractors whose individual reports are listed in the bibliography. No field work was involved. The entire study was geotechnical in nature, and no consideration was given to socioeconomic or demographic factors. These factors need to be addressed in a separate study. For all areas, field study is needed before any area is further considered. A total of 29 areas are recommended for further consideration in the Piedmont Province subregion: one area in Maryland, 8 areas in Virginia, 4 areas in North Carolina, 6 areas in South Carolina, and 10 areas in Georgia. Of the 14 exposed and 5 buried or hypothesized basins identified in the Triassic basin subregion, 6 are recommended for further study: one basin in Virginia, 3 basins in North Carolina, and 2 basins in South Carolina. Four potential candidate areas are identified within the Atlantic Coastal Plain subregion: one in Maryland, one in North Carolina, and 2 in Georgia

  4. A new bathyal sipunculan from Southern California, with ecological notes

    Science.gov (United States)

    Thompson, Bruce E.

    1980-11-01

    Golfingia (Nephasoma) nicolasi n. sp. is described. It is a long, slender species with a filiform introvert that is 6 to 7 times the length of the trunk. The species was often the numerically dominant taxon in samples collected from the San Nicolas Basin, California, and was also callected from several other basins off southern California. Analyses of several collections from the San Nicolas Basin show that the population was spatially patchy; temporal variation was also indicated but only one year was sampled adequately. Average population densities were highest at the base of the slopes descending into the basin from the highly productive Santa Rosa-Cortes Ridge and Tanner Bank. G. nicolasi appears to feed on the large amounts of organic detritus that accumulate from this source.

  5. Introduction. [usefulness of modern remote sensing techniques for studying components of California water resources

    Science.gov (United States)

    Colwell, R. N.

    1973-01-01

    Since May 1970, personnel on several campuses of the University of California have been conducting investigations which seek to determine the usefulness of modern remote sensing techniques for studying various components of California's earth resources complex. Emphasis has been given to California's water resources as exemplified by the Feather River project and other aspects of the California Water Plan. This study is designed to consider in detail the supply, demand, and impact relationships. The specific geographic areas studied are the Feather River drainage in northern California, the Chino-Riverside Basin and Imperial Valley areas in southern California, and selected portions of the west side of San Joaquin Valley in central California. An analysis is also given on how an effective benefit-cost study of remote sensing in relation to California's water resources might best be made.

  6. Influence of lithosphere and basement properties on the stretching factor and development of extensional faults across the Otway Basin, southeast Australia

    NARCIS (Netherlands)

    Kharazizadeh, N.; Schellart, W. P.; Duarte, J.C.; Hall, M.

    2017-01-01

    The NW-SE striking Otway Basin in southeastern Australia is part of the continental rift system that formed during the separation of Australia from Antarctica. The development of this sedimentary basin occurred in two phases of Late Jurassic-Early Cretaceous and Late Cretaceous rifting. The

  7. Residual basins

    International Nuclear Information System (INIS)

    D'Elboux, C.V.; Paiva, I.B.

    1980-01-01

    Exploration for uranium carried out over a major portion of the Rio Grande do Sul Shield has revealed a number of small residual basins developed along glacially eroded channels of pre-Permian age. Mineralization of uranium occurs in two distinct sedimentary units. The lower unit consists of rhythmites overlain by a sequence of black shales, siltstones and coal seams, while the upper one is dominated by sandstones of probable fluvial origin. (Author) [pt

  8. 78 FR 18849 - Disapproval of Implementation Plan Revisions; State of California; South Coast VMT Emissions...

    Science.gov (United States)

    2013-03-28

    ... the Los Angeles-South Coast Air Basin Area (``South Coast'') \\2\\ as ``extreme'' nonattainment for the... AGENCY 40 CFR Part 52 Disapproval of Implementation Plan Revisions; State of California; South Coast VMT... the Clean Air Act for the Los Angeles-South Coast Air Basin 1-hour and 8-hour ozone nonattainment...

  9. Reactivation of an idle lease to increase heavy oil recovery through application of conventional steam drive technology in a low dip slope and basin reservoir in the Midway-Sunset field, San Jaoquin Basin, California. Annual report, June 13, 1995--June 13, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Deo, M.; Jenkins, C.; Sprinkel, D.; Swain, R.; Wydrinski, R.; Schamel, S.

    1998-09-01

    This project reactivates ARCO`s idle Pru Fee lease in the Midway-Sunset field, California and conducts a continuous steamflood enhanced oil recovery demonstration aided by an integration of modern reservoir characterization and simulation methods. Cyclic steaming is being used to reestablish baseline production within the reservoir characterization phase of the project. During the demonstration phase scheduled to begin in January 1997, a continuous steamflood enhanced oil recovery will be initiated to test the incremental value of this method as an alternative to cyclic steaming. Other economically marginal Class III reservoirs having similar producibility problems will benefit from insight gained in this project. The objectives of the project are: (1) to return the shut-in portion of the reservoir to optimal commercial production; (2) to accurately describe the reservoir and recovery process; and (3) to convey the details of this activity to the domestic petroleum industry, especially to other producers in California, through an aggressive technology transfer program.

  10. San Mateo Creek Basin

    Science.gov (United States)

    The San Mateo Creek Basin comprises approximately 321 square miles within the Rio San Jose drainage basin in McKinley and Cibola counties, New Mexico. This basin is located within the Grants Mining District (GMD).

  11. Mediterranean California, Chapter 13

    Science.gov (United States)

    M.E. Fenn; E.B. Allen; L.H. Geiser

    2011-01-01

    The Mediterranean California ecoregion (CEC 1997; Fig 2.2) encompasses the greater Central Valley, Sierra foothills, and central coast ranges of California south to Mexico and is bounded by the Pacific Ocean, Sierra Nevada Mountains and Mojave Desert.

  12. California Condor Critical Habitat

    Data.gov (United States)

    California Natural Resource Agency — These Data identify (in general) the areas where critical habitat for the California Condor occur. Critical habitat for the species consists of the following 10...

  13. California-Baja California border master plan - plan maestro fronterizo California-Baja California : technical appendix.

    Science.gov (United States)

    2008-09-01

    Under the direction of the U.S. / Mexico Joint Working Committee, the California Department of : Transportation (Caltrans) and the State of Baja Californias Secretariat of Infrastructure and Urban : Development (SIDUE) hereby establish the Califor...

  14. California Bioresources Alliance Symposia

    Science.gov (United States)

    Past and upcoming events and infromation from the California Bioresources Alliance Symposium, focusing on management of organic residuals in California including manure, biosolids, food waste, agricultural wastes, green waste and wood waste.

  15. Assessment of the Impact of the California Water Project in Southern California

    Science.gov (United States)

    Bowden, L. W.; Brooner, W. G.; Bailey, H. P.; Coleman, V. B.; Dykman, P. T.; Johnson, C. W.; Pease, R. W.

    1971-01-01

    As the California State Water Project progresses and enters operation, it is suggested that changes in land use which may be monitored and anlayzed by remote sensing techniques will follow suite. Progress in each of these areas of research and automated mapping techniques to monitor these changes is presented for two specific regions: (1) the Perris Valley surrounding the future Lake Perris; and (2) the Sheep Creek Fan-Mirage Basin area of the Mojave Desert.

  16. Similarity of Cross-Sectional Characteristics of Costal Plain Streams of the Southeastern United States

    Science.gov (United States)

    Vesely, W. S.; Parola, A. C.

    2005-05-01

    The Coastal Plain physiographic region of the southeastern United States encompasses over 1.2 million km2. Analysis of data from six separate geomorphic studies conducted in five of the 19 states having a Coastal Plain region suggests that streams of the Coastal Plain region have very similar correlations betweein bankfull cross section area (R2 = 0.92, n = 123) and discharge (R2 = 0.85, n = 77) with drainage basin area, despite geographic and hydrologic differences. Analysis of these data also shows that bankfull cross section area for southeastern Coastal Plain streams is 47% less than that indicated for other eastern US rivers by Dunne and Leopold (1978). Furthermore, estimates of bankfull discharge have an average return period of 1.14 years on the annual series. These bankfull flows range from 6.2-90% of the 1.5-year flow, often considered to represent the bankfull flow condition, and 4.4-75% of the 2-year flow, which some have suggested for restoration design. The strong correlation of these data supports the concept of using regional morphologic data for initiating assessments and should be considered as an important component of restoration design for streams of the southeastern Coastal Plain.

  17. California Workforce: California Faces a Skills Gap

    Science.gov (United States)

    Public Policy Institute of California, 2011

    2011-01-01

    California's education system is not keeping up with the changing demands of the state's economy--soon, California will face a shortage of skilled workers. Projections to 2025 suggest that the economy will continue to need more and more highly educated workers, but that the state will not be able to meet that demand. If current trends persist,…

  18. Information technology and decision support tools for stakeholder-driven river basin salinity management

    Energy Technology Data Exchange (ETDEWEB)

    Quinn, N.W.T; Cozad, D.B.; Lee, G.

    2010-01-01

    Innovative strategies for effective basin-scale salinity management have been developed in the Hunter River Basin of Australia and more recently in the San Joaquin River Basin of California. In both instances web-based stakeholder information dissemination has been a key to achieving a high level of stakeholder involvement and the formulation of effective decision support salinity management tools. A common element to implementation of salinity management strategies in both river basins has been the concept of river assimilative capacity for controlling export salt loading and the potential for trading of the right to discharge salt load to the river - the Hunter River in Australia and the San Joaquin River in California. Both rivers provide basin drainage and the means of exporting salt to the ocean. The paper compares and contrasts the use of monitoring, modeling and information dissemination in the two basins to achieve environmental compliance and sustain irrigated agriculture in an equitable and socially and politically acceptable manner.

  19. Do scrapers increase downstream? Patterns in southeastern ...

    African Journals Online (AJOL)

    We measured scraper biomass and relative abundance and epilithic chlorophyll and organic matter on a single occasion at 17 sites ranging from order 1 to order 4 on five streams in southeastern Australia. Biomass of invertebrate scrapers was not related to chlorophyll concentration and was negatively related to epilithic ...

  20. Summary of southeastern group breakout sessions

    Science.gov (United States)

    Bob Ford; Charles P. Nicholson

    1993-01-01

    The breakout sessions held by the southeastern representatives at the Partners In Flight meeting in Colorado were extremely well attended Most states were represented, as well as several federal agencies (including USFS, USFWS, TVA, EPA), and non-government organizations. Two sessions were held, one to discuss a strategy of management by...

  1. Water usage in southeastern bioenergy crop production

    Science.gov (United States)

    The southeastern United States with its long growing season and mild winter temperatures has long been able to produce a variety of food, forage, and fiber crops. In addition to these crops, the Southeast is capable of producing a plethora of lignoceullosic-based bioenergy crops for conversion into ...

  2. Emerging Energy Alternatives for the Southeastern States

    Science.gov (United States)

    Stefanakos, E. K. (Editor)

    1978-01-01

    The proceedings of the first symposium on emerging energy alternatives for the Southeastern States are presented. Some topics discussed are: (1) solar energy, (2) wood energy, (3) novel energy sources, (4) agricultural and industrial process heat, (5) waste utilization, (6) energy conservation and (7) ocean thermal energy conversion.

  3. Phosphorus adsorption characteristics of selected southeastern ...

    African Journals Online (AJOL)

    The phosphorus adsorption characteristics of selected Southeastern Nigerian soils from Ikom, Bende and Ihiagwa were evaluated. P adsorption isotherm was obtained by shaking soil samples with 0, 10, 20, 30, 40 and 50 ppm P in 0.01M CaCl2 solution. P adsorption maxima (b), affinity constant (k), buffering capacity and P ...

  4. Trends in heavy oil production and refining in California

    International Nuclear Information System (INIS)

    Olsen, D.K.; Ramzel, E.B.; Pendergrass, R.A. II.

    1992-07-01

    This report is one of a series of publications assessing the feasibility of increasing domestic heavy oil production and is part of a study being conducted for the US Department of Energy. This report summarizes trends in oil production and refining in Canada. Heavy oil (10 degrees to 20 degrees API gravity) production in California has increased from 20% of the state's total oil production in the early 1940s to 70% in the late 1980s. In each of the three principal petroleum producing districts (Los Angeles Basin, Coastal Basin, and San Joaquin Valley) oil production has peaked then declined at different times throughout the past 30 years. Thermal production of heavy oil has contributed to making California the largest producer of oil by enhanced oil recovery processes in spite of low oil prices for heavy oil and stringent environmental regulation. Opening of Naval Petroleum Reserve No. 1, Elk Hills (CA) field in 1976, brought about a major new source of light oil at a time when light oil production had greatly declined. Although California is a major petroleum-consuming state, in 1989 the state used 13.3 billion gallons of gasoline or 11.5% of US demand but it contributed substantially to the Nation's energy production and refining capability. California is the recipient and refines most of Alaska's 1.7 million barrel per day oil production. With California production, Alaskan oil, and imports brought into California for refining, California has an excess of oil and refined products and is a net exporter to other states. The local surplus of oil inhibits exploitation of California heavy oil resources even though the heavy oil resources exist. Transportation, refining, and competition in the market limit full development of California heavy oil resources

  5. The tenebrionidae of california: a time sensitive snapshot assessment.

    Science.gov (United States)

    Aalbu, Rolf L; Smith, Aaron D

    2014-01-01

    DUE TO A DIVERSITY OF HABITATS AND ITS GEOLOGIC HISTORY, THE US STATE OF CALIFORNIA HOSTS A SPECTACULAR ASSEMBLAGE OF DARKLING BEETLE SPECIES (COLEOPTERA: Tenebrionidae). In addition to being part of the California Floristic Province, one of 34 global biodiversity hotspots identified by Conservation International, California also has additional areas which are parts of the Great Basin, Mojave, and Sonoran deserts. California is divided into nine floristic regions. Each region is assessed in terms of faunal composition and endemism. A "snapshot" of our present knowledge of the Tenebrionidae indicates that 447 currently recognized species, representing 108 genera, occur in California of which one hundred and ninety are endemic. California is compared to other nearby regions in diversity and endemism. An analysis of currently valid species vs a more realistic species account based on unpublished records of likely synonyms and known species yet to be described in the scientific literature is presented. The California Floristic Region, rather than other more arid parts of California, has the highest number of total and endemic species. Because of their high diversity and endemism, tenebrionids could potentially provide a valuable tool for monitoring the environment for conservation purposes.

  6. Southeastern Power Administration 2008 Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    None

    2008-12-29

    Dear Secretary Chu: I am pleased to submit Southeastern Power Administration’s (Southeastern’s) fiscal year (FY) 2008 Annual Report for your review. The information included in this document reflects our agency’s programs, accomplishments, operational and financial activities for the 12-month period beginning October 1, 2007 and ending September 30, 2008. Southeastern marketed more than 4.5 billion kilowatt-hours of energy to 491 wholesale customers in ten southeastern states this past year. Revenues from the sale of this power totaled approximately $263 million. Drought conditions persisted in the southeastern region of the United States during FY 2008 placing strains on our natural and financial resources. Power purchases for FY 2008 totaled $91 million. Approximately $44 million of this amount was for replacement power which is paid only during adverse water conditions in order to meet our customers’ contract requirements. With the continued financial assistance and support of our Federal power customers, funding for capitalized equipment purchases and replacements at U.S. Army Corps of Engineers’ (Corps) hydroelectric projects provided much needed repairs and maintenance for these aging facilities. Southeastern’s cyber and physical security programs continued to be reviewed and updated to meet Department of Energy (DOE), Homeland Security, and North American Electric Reliability Corporation (NERC) standards and requirements. In the coming year, Southeastern will continue open communication and cooperation with DOE, the Federal power customers, and the Corps to maximize the benefits of our region’s water resources. Although competing uses of water and the prolonged drought conditions will present another challenging year for our agency, Southeastern’s employees will meet these challenges and continue to provide reliable hydroelectric power to the people in the southeast. Sincerely, Kenneth E.Legg Administrator

  7. Use of land located within Eselnita drainage basin

    Directory of Open Access Journals (Sweden)

    DANIELA VLAD

    2011-12-01

    Full Text Available Developed on the south-eastern side of Almãjului Mountains, Eşelniţa drainage basin neighbours upon the following basins: upon S – SV with Mala, upon SV - V with Mraconia, upon V - NV with Berzasca, upon NV - NNE with Nera and on the NNE – SE direction with Cerna. The basin has a surface of 77 km2 and present a 5th degree hydrographic network according to Horton-Strahler ranking system, tributary to Danube by means of Eşelniţa main collector. Among surfaces belonging to various categories of use of land located within Eselnita drainage basin, there may be noticed the high share of forest and secondary grazing lands, although the latter have a smaller surface in comparison to the first ones. Therefore, the types of use of land located within the drainage basin are distinguished by the high share of surfaces of forests to the detriment of predominant agricultural land proven by using of some quantitative indexes defining the character of the Eselnita drainage basin as belonging to forestry type. Also the impact of human activities and number of inhabitants do not have a very damaging influence on the land corresponding to the basin, therefore it has a naturality index indicating an ecological equilibrium closed to the natural one.

  8. General subsurface geology of southeastern New Mexico with special reference to its structural stability

    International Nuclear Information System (INIS)

    Hills, J.

    1979-01-01

    Southeastern New Mexico east of the Pecos River is a tectonically stable area with no major fault movements for the past 250 million years. No major tectonic adjustments are expected in the next million years. Minor tectonic adjustments during Triassic time (200 to 180 million years ago) and early Tertiary time (70 million years ago) have resulted in deepening and eastward tilting of the Delaware basin. These tectonic adjustments have resulted in the opening of joints and consequent solution of the upper part of the Salado salt. Compaction of Pennsylvanian and Lower Permian sediments has also contributed to the basin subsidence. This effect has been most severe on the west edge of the basin near the Pecos River and in the southeast edge of the basin adjoining Winkler County, Texas. Recent minor seismic activity is probably the result of petroleum secondary recovery operations. This seismic activity may result in the release of strain and may contribute to the long term tectonic stability of the area

  9. Pull-apart basin formation and development in narrow transform zones with application to the Dead Sea Basin

    NARCIS (Netherlands)

    Smit, J.H.W.; Brun, J.P.; Cloetingh, S.A.P.L.; Ben-Avraham, Z.

    2008-01-01

    Contrary to other examples, like Death Valley, California, and the Sea of Marmara, Turkey, the Dead Sea-type pull-apart basins form within a narrow transform corridor between strike-slip faults that are less than 10 km apart, much smaller than the crustal thickness of 35 km. In this paper we

  10. Distribution and Climatic Relationships of the American Pika (Ochotona princeps) in the Sierra Nevada and Western Great Basin, U.S.A.; Periglacial Landforms as Refugia in Warming Climates

    Science.gov (United States)

    Constance I. Millar; Robert D. Westfall

    2010-01-01

    We used a rapid assessment to survey American pika (Ochotona princeps) populations and documented 420 pika site occurrences in southwestern U.S.A. These included 329 sites from the Sierra Nevada (SN), California; 67 from six southwestern Great Basin (swGB) ranges, California and Nevada; 16 from three central Great Basin ranges, Nevada; and 8 from...

  11. Field trip guide to selected studies of the Southwest Mineral and Environmental Investigations Project in southeastern Arizona

    Science.gov (United States)

    Houser, B.B.; Gettings, M.E.; Bultman, M.W.; Gray, Floyd; Caruthers, K.R.; Hirschberg, D.M.

    1999-01-01

    The Southwest Mineral and Environmental Investigations Project is designed to address issues raised by rapid urban development in the basins of the southwestern U.S. These issues require objective geoscientific data that can be used by land managers and stakeholders to develop informed land and water use strategies. The project integrates new and existing geologic, geophysical, and geochemical data, and imagery to provide three-dimensional visualizations of the basins of southeastern Arizona. Emphasis is on developing better knowledge of the aquifer systems of both the basins and the ranges, on acquiring background and baseline information, and on determining the distribution of metals related to mineralization and the fate of these metals in surface and subsurface environments. The products of the project will be used in resolving issues of water quality and quantity, in understanding environmental impacts such as riparian ecosystem maintenace, and in evaluating mineral resources beneath and within the basins. The field trip highlights three topics and areas (figs. 1 and 2): (1) geology and geophysics of the upper San Pedro and upper Santa Cruz basins (M.E. Gettings, M. W. Bultman, and B.B. Houser), (2) geology, geophysics, and mineral resource potential of the San Rafael basin (M.W. Bultman), and (3) hydrology and aqueous geochemistry of the Red Mountain and Sonoita Creek drainage system (Floyd Gray). The trip guide, which begins and ends in Tucson, Arizona, also includes commentary on the cultural and mining history of the area.

  12. THE ADVANCED CHEMISTRY BASINS PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    William Goddard; Peter Meulbroek; Yongchun Tang; Lawrence Cathles III

    2004-04-05

    In the next decades, oil exploration by majors and independents will increasingly be in remote, inaccessible areas, or in areas where there has been extensive shallow exploration but deeper exploration potential may remain; areas where the collection of data is expensive, difficult, or even impossible, and where the most efficient use of existing data can drive the economics of the target. The ability to read hydrocarbon chemistry in terms of subsurface migration processes by relating it to the evolution of the basin and fluid migration is perhaps the single technological capability that could most improve our ability to explore effectively because it would allow us to use a vast store of existing or easily collected chemical data to determine the major migration pathways in a basin and to determine if there is deep exploration potential. To this end a the DOE funded a joint effort between California Institute of Technology, Cornell University, and GeoGroup Inc. to assemble a representative set of maturity and maturation kinetic models and develop an advanced basin model able to predict the chemistry of hydrocarbons in a basin from this input data. The four year project is now completed and has produced set of public domain maturity indicator and maturation kinetic data set, an oil chemistry and flash calculation tool operable under Excel, and a user friendly, graphically intuitive basin model that uses this data and flash tool, operates on a PC, and simulates hydrocarbon generation and migration and the chemical changes that can occur during migration (such as phase separation and gas washing). The DOE Advanced Chemistry Basin Model includes a number of new methods that represent advances over current technology. The model is built around the concept of handling arbitrarily detailed chemical composition of fluids in a robust finite-element 2-D grid. There are three themes on which the model focuses: chemical kinetic and equilibrium reaction parameters, chemical

  13. Groundwater quality in Coachella Valley, California

    Science.gov (United States)

    Dawson, Barbara J. Milby; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Coachella Valley is one of the study areas being evaluated. The Coachella study area is approximately 820 square miles (2,124 square kilometers) and includes the Coachella Valley groundwater basin (California Department of Water Resources, 2003). Coachella Valley has an arid climate, with average annual rainfall of about 6 inches (15 centimeters). The runoff from the surrounding mountains drains to rivers that flow east and south out of the study area to the Salton Sea. Land use in the study area is approximately 67 percent (%) natural, 21% agricultural, and 12% urban. The primary natural land cover is shrubland. The largest urban areas are the cities of Indio and Palm Springs (2010 populations of 76,000 and 44,000, respectively). Groundwater in this basin is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from surrounding mountains. The primary aquifers in Coachella Valley are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells in Coachella Valley are completed to depths between 490 and 900 feet (149 to 274 meters), consist of solid casing from the land surface to a depth of 260 to 510 feet (79 to 155 meters), and are screened or perforated below the solid casing. Recharge to the groundwater system is primarily runoff from the surrounding mountains, and by direct infiltration of irrigation. The primary sources of discharge are pumping wells, evapotranspiration, and underflow to

  14. Southeastern Power Administration 2007 Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    None

    2007-12-28

    Dear Secretary Chu: I am proud to submit Southeastern Power Administration’s (Southeastern’s) fiscal year (FY) 2007 Annual Report for your review. The information included in this report reflects Southeastern’s programs, accomplishments, and financial activities for the 12-month period beginning October 1, 2006 and ending September 30, 2007. Southeastern marketed more than 5 billion kilowatt-hours of energy to 492 wholesale Federal power customers in an 11-state marketing area in FY 2007. Revenues from the sale of this power totaled approximately $219 million. Drought conditions continued to plague the southeast region of the United States during 2007 placing strains on our natural and financial resources. Southeastern purchased more than $40 million in replacement power to meet customer contract requirements to ensure the continued reliability of our nation’s power grid. With the financial assistance and support of our Federal power customers, continued funding for capitalized equipment replacements at various Corps of Engineers’ (Corps) hydroelectric projects provided much needed repairs and maintenance for aging facilities. Southeastern’s cyber and physical security program continued to be reviewed and updated to meet Department of Energy (DOE), Homeland Security, and North American Electric Reliability Corporation standards and requirements. Plans for the upcoming year include communication and cooperation with DOE, Federal power customers, and the Corps to maximize the benefits of our nation’s water resources. Competition for the use of water and the prolonged drought conditions will present another challenging year for our agency. The employees at Southeastern will be proactive in meeting these challenges and providing reliable hydroelectric power to the people in the southeast. Sincerely, Kenneth E. Legg Administrator

  15. Teale Ground Water Basins

    Data.gov (United States)

    California Department of Resources — California Spatial Information System (CaSIL) is a project designed to improve access to geo-spatial and geo-spatial related data information throughout the state of...

  16. California's congestion management program

    International Nuclear Information System (INIS)

    Nash, A.

    1992-01-01

    One of the hottest topics in transportation planning today is California's Congestion Management Program (CMP). California's program has been suggested as a model to the rest of the United States for addressing transportation problems and for conforming to the federal Clean Air Act. This article introduces California's Congestion Management Program, describes some problems related to California's CMP legislation, outlines the major CMP elements, and briefly explains the issue of the environmental impact of CMPs. This information might assist others in developing their own CMP programs

  17. A regional tidal/subtidal circulation model of the southeastern Bering Sea: development, sensitivity analyses and hindcasting

    Science.gov (United States)

    Hermann, Albert J.; Stabeno, Phyllis J.; Haidvogel, Dale B.; Musgrave, David L.

    2002-12-01

    A regional eddy-resolving primitive equation circulation model was used to simulate circulation on the southeastern Bering Sea (SEBS) shelf and basin. This model resolves the dominant observed mean currents, eddies and meanders in the region, and simultaneously includes both tidal and subtidal dynamics. Circulation, temperature, and salinity fields for years 1995 and 1997 were hindcast, using daily wind and buoyancy flux estimates, and tidal forcing derived from a global model. This paper describes the development of the regional model, a comparison of model results with available Eulerian and Lagrangian data, a comparison of results between the two hindcast years, and a sensitivity analysis. Based on these hindcasts and sensitivity analyses, we suggest the following: (1) The Bering Slope Current is a primary source of large ( ˜100 km diameter) eddies in the SEBS basin. Smaller meanders are also formed along the 100 m isobath on the southeastern shelf, and along the 200-m isobath near the shelf break. (2) There is substantial interannual variability in the statistics of eddies within the basin, driven by variability in the strength of the ANSC. (3) The mean flow on the shelf is not strongly sensitive to changes in the imposed strength of the ANSC; rather, it is strongly sensitive to the local wind forcing. (4) Vertical mixing in the SEBS is strongly affected by both tidal and subtidal dynamics. Strongest mixing in the SEBS may in fact occur between the 100- and 400-m isobaths, near the Pribilof Islands, and in Unimak Pass.

  18. Tectonic comparisons of Caucasus and California cordillera

    Energy Technology Data Exchange (ETDEWEB)

    Mulhern, M.E.

    1986-05-01

    Many parallels exist between the Caucasus region, shaped as the Eurasian and Arabian-African plates converged during the Cenozoic Alpine orogeny, and California, where the North American and Pacific plates interact. The Forecaucasian platform hosts many large oil and gas fields in molasse-filled foredeeps of high heat flow. Production is from Permian to Pliocene tight anticlines on reverse faults, diapiric structures, shoe-string sands of the prolific Maikop series, and Tertiary fanglomerates and sand lenses. Although not an exact parallel, this production suggests potential in Paleozoic and Mesozoic marine and Tertiary fanglomeratic, tuffaceous, and fluvial sediments in basins of the sparsely drilled Basin and Range. The Greater Caucasus, like the Sierra Nevada, show Paleozoic-Mesozoic geosynclinal sedimentation, subduction, and granitic magmatism. The former have undergone much folding, thrusting, and Quaternary volcanism. Jurassic bituminous limestone is exposed, a source for the petroliferous Transcaucasian Intermontane depression. The latter is filled with thick Mesozoic-Cenozoic flysch and molasse and, like California's Great Valley forearc basin, orogenic terrane and permeable soils favor enology. Sources also include Eocene and Miocene diatomaceous and bituminous clays. Reservoirs include prolific Pliocene sands, Eocene olistostromes, fractured tuffaceous rocks, and Cretaceous-Miocene sandstones in anticlines and stratigraphic traps. Migration to basin flanks was aided by compression. The Lesser Caucasus, a continuation of the main ophiolite foldbelt of Turkey, shares a subduction and accretionary history with the Franciscan melange. This microplate was obducted to Eurasia as the prong-shaped Arabian plate moved it and other microplates of the east Mediterranean in several directions (the Turkish microplate dextrally along the North Anatolian transform fault) and deformed wide areas.

  19. Groundwater quality in the Mojave area, California

    Science.gov (United States)

    Dawson, Barbara J. Milby; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Four groundwater basins along the Mojave River make up one of the study areas being evaluated. The Mojave study area is approximately 1,500 square miles (3,885 square kilometers) and includes four contiguous groundwater basins: Upper, Middle, and Lower Mojave River Groundwater Basins, and the El Mirage Valley (California Department of Water Resources, 2003). The Mojave study area has an arid climate, and is part of the Mojave Desert. Average annual rainfall is about 6 inches (15 centimeters). Land use in the study area is approximately 82 percent (%) natural (mostly shrubland), 4% agricultural, and 14% urban. The primary crops are pasture and hay. The largest urban areas are the cities of Victorville, Hesperia, and Apple Valley (2010 populations of 116,000, 90,000 and 69,000, respectively). Groundwater in these basins is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from surrounding mountains. The primary aquifers in the Mojave study area are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells in the Mojave study area are completed to depths between 200 and 600 feet (18 to 61 meters), consist of solid casing from the land surface to a depth of 130 to 420 feet (40 to 128 meters), and are screened or perforated below the solid casing. Recharge to the groundwater system is primarily runoff from the mountains to the south, mostly through the Mojave River channel. The primary sources

  20. Adaptation of Arabidopsis thaliana to the Yangtze River basin.

    Science.gov (United States)

    Zou, Yu-Pan; Hou, Xing-Hui; Wu, Qiong; Chen, Jia-Fu; Li, Zi-Wen; Han, Ting-Shen; Niu, Xiao-Min; Yang, Li; Xu, Yong-Chao; Zhang, Jie; Zhang, Fu-Min; Tan, Dunyan; Tian, Zhixi; Gu, Hongya; Guo, Ya-Long

    2017-12-28

    Organisms need to adapt to keep pace with a changing environment. Examining recent range expansion aids our understanding of how organisms evolve to overcome environmental constraints. However, how organisms adapt to climate changes is a crucial biological question that is still largely unanswered. The plant Arabidopsis thaliana is an excellent system to study this fundamental question. Its origin is in the Iberian Peninsula and North Africa, but it has spread to the Far East, including the most south-eastern edge of its native habitats, the Yangtze River basin, where the climate is very different. We sequenced 118 A. thaliana strains from the region surrounding the Yangtze River basin. We found that the Yangtze River basin population is a unique population and diverged about 61,409 years ago, with gene flows occurring at two different time points, followed by a population dispersion into the Yangtze River basin in the last few thousands of years. Positive selection analyses revealed that biological regulation processes, such as flowering time, immune and defense response processes could be correlated with the adaptation event. In particular, we found that the flowering time gene SVP has contributed to A. thaliana adaptation to the Yangtze River basin based on genetic mapping. A. thaliana adapted to the Yangtze River basin habitat by promoting the onset of flowering, a finding that sheds light on how a species can adapt to locales with very different climates.

  1. Superimposed versus residual basin: The North Yellow Sea Basin

    Directory of Open Access Journals (Sweden)

    Wenyong Li

    2012-01-01

    Full Text Available The North Yellow Sea Basin is a Mesozoic and Cenozoic basin. Based on basin-margin facies, sedimentary thinning, size and shape of the basin and vitrinite reflectance, North Yellow Sea Basin is not a residual basin. Analysis of the development of the basin’s three structural layers, self-contained petroleum systems, boundary fault activity, migration of the Mesozoic–Cenozoic sedimentation centers, different basin structures formed during different periods, and superposition of a two-stage extended basin and one-stage depression basin, the North Yellow Sea Basin is recognized as a superimposed basin.

  2. Irregular plate boundary controls on Foreland Basin sedimentation (Miocene, Kahramanmaraş Foreland Basin, SE Turkey)

    Science.gov (United States)

    Gül, Murat; Gürbüz, Kemal; Cronin, Bryan T.

    2015-11-01

    The northern movement of the Arabian Plate led to the development of a compressional regime in the south-eastern part of Turkey after the Late Cretaceous. The collision of the Arabian Plate with the Anatolide-Taurides Platform and subsequent development of the Kahramanmaraş Foreland Basin at the beginning of the Miocene evolved as a result of this movement. An irregular plate geometry or promontory of the Arabian Plate caused partitioning of the plate margin (precollision-collision-postcollision). This irregular plate boundary was delimited by western and northern boundary faults and an interior basin fault. The NW-oriented small wedge top basins on the overlying Anatolide-Taurides Platform obliquely cut through the foredeep basin. The region (across the wedge top basin) on the irregular promontory of the underlying Arabian Plate contains different sedimentation depocentres. Small fining-upward submarine fan deposits (including pebbly channel deposits and coarsening-upward lobe sequences) are located at the centre of the irregular part of the plate (in the Tanır region) and overlie planktic foraminifera-bearing claystones. These submarine fan sediments pass outboard into distal interbedded turbidite claystones and siltstones in a downdip direction (S-SE). The boundary fault intersection of the promontory led to the development of a submarine slope environment with irregular sea-floor topography in the Fırnız area (4-5 km south-east of the Tanır region). The slump deposits, sandy debrites, and fine-grained thin-bedded turbidites filled this region. Structural alignments and seismicity associated with the plate margin were the main controlling factors on the geometry of the depocentre, sediment quantity, sediment input, sedimentary facies, local sea level changes, and post-sedimentary deformation in the Kahramanmaraş Foreland Basin.

  3. Chronology, sedimentology, and microfauna of groundwater discharge deposits in the central Mojave Desert, Valley Wells, California

    Science.gov (United States)

    Pigati, Jeffrey S.; Miller, David M.; Bright, Jordon E.; Mahan, Shannon; Nekola, Jeffrey C.; Paces, James B.

    2011-01-01

    During the late Pleistocene, emergent groundwater supported persistent and long-lived desert wetlands in many broad valleys and basins in the American Southwest. When active, these systems provided important food and water sources for local fauna, supported hydrophilic and phreatophytic vegetation, and acted as catchments for eolian and alluvial sediments. Desert wetlands are represented in the geologic record by groundwater discharge deposits, which are also called spring or wetland deposits. Groundwater discharge deposits contain information on the timing and magnitude of past changes in water-table levels and, thus, are a source of paleohydrologic and paleoclimatic information. Here, we present the results of an investigation of extensive groundwater discharge deposits in the central Mojave Desert at Valley Wells, California. We used geologic mapping and stratigraphic relations to identify two distinct wetland sequences at Valley Wells, which we dated using radiocarbon, luminescence, and uranium-series techniques. We also analyzed the sediments and microfauna (ostracodes and gastropods) to reconstruct the specific environments in which they formed. Our results suggest that the earliest episode of high water-table conditions at Valley Wells began ca. 60 ka (thousands of calendar yr B.P.), and culminated in peak discharge between ca. 40 and 35 ka. During this time, cold (4–12 °C) emergent groundwater supported extensive wetlands that likely were composed of a wet, sedge-rush-tussock meadow mixed with mesic riparian forest. After ca. 35 ka, the water table dropped below the ground surface but was still shallow enough to support dense stands of phreatophytes through the Last Glacial Maximum (LGM). The water table dropped further after the LGM, and xeric conditions prevailed until modest wetlands returned briefly during the Younger Dryas cold event (13.0–11.6 ka). We did not observe any evidence of wet conditions during the Holocene at Valley Wells. The timing

  4. A 150 kyr-long hydroclimate record from Southern California using Searles Lake sediments: initial findings

    Science.gov (United States)

    Stroup, J. S.; Olson, K. J.; McGee, D.; Lowenstein, T. K.; Smoot, J. P.; Janick, J. J.; Lund, S.; Peaple, M.; Chen, C. Y.; Feakins, S. J.; Litwin, R.

    2017-12-01

    Over decadal to millennial scales, the southwestern U.S has experienced large shifts in hydroclimate ranging from pluvial conditions to extreme droughts. Direct observations, modeling and proxy data suggest precipitation amount and distribution are controlled by multiple factors including the position of the Hadley Cell, strength of the Aleutian Low and North Pacific High, ENSO and the path of winter storm tracks. Sediment records from closed basin lakes provide a means for assessing how hydrologic conditions have responded to past climate changes; however, long (>50 ka) paleoclimate records from lakes are rare and high-resolution age models are challenging to obtain. Searles Lake, in southeastern California, contains a sedimentary record that spans from the Holocene to the Pliocene at high resolution. Previous drill core studies from the basin used stratigraphy and sediment mineralogy to interpret paleoenvironmental changes and have demonstrated that the lake's sediments are able to be precisely dated. These results provide a strong foundation for new high-resolution investigations of the lake sediments. In January 2017, our group collected a new 80 m-long core with the aim of reconstructing hydrologic changes over the last 150 ka at millennial or better resolution. The core was split at the National Lacustrine Core Facility (LacCore) in June. The core contains alternating evaporite layers and finely laminated muds which likely indicate times of dryer and wetter conditions. Despite the challenge of alternating lithologies, core recovery and quality are extremely high. Here, we will present our initial chronological and stratigraphic findings. The core record will be dated using a combination of U/Th, 14C and magnetostratigraphy. We will compare our initial stratigraphic description to the existing Searles Lake literature as well as other records from the region, such as data from Devils Hole. These results provide the framework upon which we will develop detailed

  5. Precipitation and Runoff Simulations of the Carson Range and Pine Nut Mountains, and Updated Estimates of Ground-Water Inflow and the Ground-Water Budgets for Basin-Fill Aquifers of Carson Valley, Douglas County, Nevada, and Alpine County, California

    Science.gov (United States)

    Jeton, Anne E.; Maurer, Douglas K.

    2007-01-01

    Recent estimates of ground-water inflow to the basin-fill aquifers of Carson Valley, Nevada, and California, from the adjacent Carson Range and Pine Nut Mountains ranged from 22,000 to 40,000 acre-feet per year using water-yield and chloride-balance methods. In this study, watershed models were developed for watersheds with perennial streams and for watersheds with ephemeral streams in the Carson Range and Pine Nut Mountains to provide an independent estimate of ground-water inflow. This report documents the deve