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Sample records for unit colorado river

  1. Eolian sand transport pathways in the southwestern United States: Importance of the Colorado River and local sources

    Science.gov (United States)

    Muhs, D.R.; Reynolds, R.L.; Been, J.; Skipp, G.

    2003-01-01

    Geomorphologists have long recognized that eolian sand transport pathways extend over long distances in desert regions. Along such pathways, sediment transport by wind can surmount topographic obstacles and cross major drainages. Recent studies have suggested that three distinct eolian sand transport pathways exist (or once existed) in the Mojave and Sonoran Desert regions of the southwestern United States. One hypothesized pathway is colian sand transport from the eastern Mojave Desert of California into western Arizona, near Parker, and would require sand movement across what must have been at least a seasonally dry Colorado River valley. We tested this hypothesis by mineralogical, geochemical and magnetic analyses of eolian sands on both sides of the Colorado River, as well as sediment from the river itself. Results indicate that dunes on opposite sides of the Colorado River are mineralogically distinct: eastern California dunes are feldspar-rich whereas western Arizona dunes are quartz-rich, derived from quartz-rich Colorado River sediments. Because of historic vegetation changes, little new sediment from the Colorado River is presently available to supply the Parker dunes. Based on this study and previous work, the Colorado River is now known to be the source of sand for at least three of the major dune fields of the Sonoran Desert of western Arizona and northern Mexico. On the other hand, locally derived alluvium appears to be a more important source of dune fields in the Mojave Desert of California. Although many geomorphologists have stressed the importance of large fluvial systems in the origin of desert dune fields, few empirical data actually exist to support this theory. The results presented here demonstrate that a major river system in the southwestern United States is a barrier to the migration of some dune fields, but essential to the origin of others. Published by Elsevier Science Ltd.

  2. Point sources of emerging contaminants along the Colorado River Basin: Source water for the arid Southwestern United States

    Science.gov (United States)

    Jones-Lepp, Tammy L.; Sanchez, Charles; Alvarez, David A.; Wilson, Doyle C.; Taniguchi-Fu, Randi-Laurant

    2012-01-01

    Emergingcontaminants (ECs) (e.g., pharmaceuticals, illicit drugs, personal care products) have been detected in waters across the UnitedStates. The objective of this study was to evaluate pointsources of ECs along the ColoradoRiver, from the headwaters in Colorado to the Gulf of California. At selected locations in the ColoradoRiver Basin (sites in Colorado, Utah, Nevada, Arizona, and California), waste stream tributaries and receiving surface waters were sampled using either grab sampling or polar organic chemical integrative samplers (POCIS). The grab samples were extracted using solid-phase cartridge extraction (SPE), and the POCIS sorbents were transferred into empty SPEs and eluted with methanol. All extracts were prepared for, and analyzed by, liquid chromatography-electrospray-ion trap mass spectrometry (LC-ESI-ITMS). Log Dow values were calculated for all ECs in the study and compared to the empirical data collected. POCIS extracts were screened for the presence of estrogenic chemicals using the yeast estrogen screen (YES) assay. Extracts from the 2008 POCIS deployment in the Las Vegas Wash showed the second highest estrogenicity response. In the grab samples, azithromycin (an antibiotic) was detected in all but one urban waste stream, with concentrations ranging from 30 ng/L to 2800 ng/L. Concentration levels of azithromycin, methamphetamine and pseudoephedrine showed temporal variation from the Tucson WWTP. Those ECs that were detected in the main surface water channels (those that are diverted for urban use and irrigation along the ColoradoRiver) were in the region of the limit-of-detection (e.g., 10 ng/L), but most were below detection limits.

  3. Geophysical data collected during the 2014 minute 319 pulse flow on the Colorado River below Morelos Dam, United States and Mexico

    Science.gov (United States)

    Kennedy, Jeffrey R.; Callegary, James B.; Macy, Jamie P.; Reyes-Lopez, Jaime; Pérez-Flores, Marco

    2017-05-09

    Geophysical methods were used to monitor infiltration during a water release, referred to as a “pulse flow,” in the Colorado River delta in March and April 2014. The pulse flow was enabled by Minute 319 of the 1944 United States–Mexico Treaty concerning water of the Colorado River. Fieldwork was carried out by the U.S. Geological Survey and the Centro de Investigación Científica y de Educación Superior de Ensenada as part of a binational effort to monitor the hydrologic effects of the pulse flow along the limitrophe (border) reach of the Colorado River and into Mexico. Repeat microgravity measurements were made at 25 locations in the southern limitrophe reach to quantify aquifer storage change during the pulse flow. Observed increases in storage along the river were greater with distance to the south, and the amount of storage change decreased away from the river channel. Gravity data at four monitoring well sites indicate specific yield equal to 0.32±0.05. Electromagnetic induction methods were used at 12 transects in the limitrophe reach of the river along the United States– Mexico border, and farther south into Mexico. These data, which are sensitive to variation in soil texture and water content, suggest relatively homogeneous conditions. Repeat direct-current resistivity measurements were collected at two locations to monitor groundwater elevation. Results indicate rapid groundwater-level rise during the pulse flow in the limitrophe reach and smaller variation at a more southern transect. Together, these data are useful for hydrogeologic characterization and hydrologic model development. Electronic data files are provided in the accompanying data release (Kennedy and others, 2016a).

  4. Colorado River Mile System, Tenths of Miles

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This coverage contains points representing tenth of miles in the GCMRC river mile system. The points fall along the centerline of the Colorado River from Glen Canyon...

  5. Groundwater-Quality Data in the Colorado River Study Unit, 2007: Results from the California GAMA Program

    Science.gov (United States)

    Goldrath, Dara A.; Wright, Michael T.; Belitz, Kenneth

    2010-01-01

    Groundwater quality in the 188-square-mile Colorado River Study unit (COLOR) was investigated October through December 2007 as part of the Priority Basin Project of the California State Water Resources Control Board (SWRCB) Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project was developed in response to the Groundwater Quality Monitoring Act of 2001, and the U.S. Geological Survey (USGS) is the technical project lead. The Colorado River study was designed to provide a spatially unbiased assessment of the quality of raw groundwater used for public water supplies within COLOR, and to facilitate statistically consistent comparisons of groundwater quality throughout California. Samples were collected from 28 wells in three study areas in San Bernardino, Riverside, and Imperial Counties. Twenty wells were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the Study unit; these wells are termed 'grid wells'. Eight additional wells were selected to evaluate specific water-quality issues in the study area; these wells are termed `understanding wells.' The groundwater samples were analyzed for organic constituents (volatile organic compounds [VOC], gasoline oxygenates and degradates, pesticides and pesticide degradates, pharmaceutical compounds), constituents of special interest (perchlorate, 1,4-dioxane, and 1,2,3-trichlorpropane [1,2,3-TCP]), naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), and radioactive constituents. Concentrations of naturally occurring isotopes (tritium, carbon-14, and stable isotopes of hydrogen and oxygen in water), and dissolved noble gases also were measured to help identify the sources and ages of the sampled groundwater. In total, approximately 220 constituents and water-quality indicators were investigated. Quality-control samples (blanks, replicates, and matrix spikes) were collected at

  6. Salinization of the Upper Colorado River - Fingerprinting Geologic Salt Sources

    Science.gov (United States)

    Tuttle, Michele L.W.; Grauch, Richard I.

    2009-01-01

    Salt in the upper Colorado River is of concern for a number of political and socioeconomic reasons. Salinity limits in the 1974 U.S. agreement with Mexico require the United States to deliver Colorado River water of a particular quality to the border. Irrigation of crops, protection of wildlife habitat, and treatment for municipal water along the course of the river also place restrictions on the river's salt content. Most of the salt in the upper Colorado River at Cisco, Utah, comes from interactions of water with rock formations, their derived soil, and alluvium. Half of the salt comes from the Mancos Shale and the Eagle Valley Evaporite. Anthropogenic activities in the river basin (for example, mining, farming, petroleum exploration, and urban development) can greatly accelerate the release of constituents from these geologic materials, thus increasing the salt load of nearby streams and rivers. Evaporative concentration further concentrates these salts in several watersheds where agricultural land is extensively irrigated. Sulfur and oxygen isotopes of sulfate show the greatest promise for fingerprinting the geologic sources of salts to the upper Colorado River and its major tributaries and estimating the relative contribution from each geologic formation. Knowing the salt source, its contribution, and whether the salt is released during natural weathering or during anthropogenic activities, such as irrigation and urban development, will facilitate efforts to lower the salt content of the upper Colorado River.

  7. 76 FR 61382 - Colorado River Basin Salinity Control Advisory Council

    Science.gov (United States)

    2011-10-04

    ... Bureau of Reclamation Colorado River Basin Salinity Control Advisory Council AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. ] SUMMARY: The Colorado River Basin Salinity Control Advisory Council (Council) was established by the Colorado River Basin Salinity Control Act of 1974 (Pub....

  8. 75 FR 25877 - Colorado River Basin Salinity Control Advisory Council

    Science.gov (United States)

    2010-05-10

    ... Bureau of Reclamation Colorado River Basin Salinity Control Advisory Council AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The Colorado River Basin Salinity Control Advisory Council (Council) was established by the Colorado River Basin Salinity Control ] Act of 1974...

  9. 78 FR 70574 - Colorado River Basin Salinity Control Advisory Council

    Science.gov (United States)

    2013-11-26

    ....20350010.REG0000, RR04084000] Colorado River Basin Salinity Control Advisory Council AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The Colorado River Basin Salinity Control Advisory Council (Council) was established by the Colorado River Basin Salinity Control Act of 1974 (Pub....

  10. 77 FR 23508 - Colorado River Basin Salinity Control Advisory Council

    Science.gov (United States)

    2012-04-19

    ... Bureau of Reclamation Colorado River Basin Salinity Control Advisory Council AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The Colorado River Basin Salinity Control Advisory Council (Council) was established by the Colorado River Basin Salinity Control Act of 1974 (Pub....

  11. 75 FR 27360 - Colorado River Basin Salinity Control Advisory Council

    Science.gov (United States)

    2010-05-14

    ... Bureau of Reclamation Colorado River Basin Salinity Control Advisory Council AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The Colorado River Basin Salinity Control Advisory Council (Council) was established by the Colorado River Basin Salinity Control Act of 1974 (Pub....

  12. 75 FR 66389 - Colorado River Basin Salinity Control Advisory Council

    Science.gov (United States)

    2010-10-28

    ... Bureau of Reclamation Colorado River Basin Salinity Control Advisory Council AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The Colorado River Basin Salinity Control Advisory Council (Council) was established by the Colorado River Basin Salinity Control Act of 1974 (Pub....

  13. 76 FR 24515 - Colorado River Basin Salinity Control Advisory Council

    Science.gov (United States)

    2011-05-02

    ... Bureau of Reclamation Colorado River Basin Salinity Control Advisory Council AGENCY: Bureau of... Committee Act, the Bureau of Reclamation announces that the Colorado River Basin Salinity Control Advisory...) 524-3826; e-mail at: kjacobson@usbr.gov . SUPPLEMENTARY INFORMATION: The Colorado River Basin...

  14. 77 FR 61784 - Colorado River Basin Salinity Control Advisory Council

    Science.gov (United States)

    2012-10-11

    ... Bureau of Reclamation Colorado River Basin Salinity Control Advisory Council AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The Colorado River Basin Salinity Control Advisory Council (Council) was established by the Colorado River Basin Salinity Control Act of 1974 (Pub....

  15. 78 FR 23784 - Colorado River Basin Salinity Control Advisory Council

    Science.gov (United States)

    2013-04-22

    ... Bureau of Reclamation Colorado River Basin Salinity Control Advisory Council AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The Colorado River Basin Salinity Control Advisory Council (Council) was established by the Colorado River Basin Salinity Control Act of 1974...

  16. Documentation of input datasets for the soil-water balance groundwater recharge model of the Upper Colorado River Basin

    Science.gov (United States)

    Tillman, Fred D

    2015-01-01

    The Colorado River and its tributaries supply water to more than 35 million people in the United States and 3 million people in Mexico, irrigating more than 4.5 million acres of farmland, and generating about 12 billion kilowatt hours of hydroelectric power annually. The Upper Colorado River Basin, encompassing more than 110,000 square miles (mi2), contains the headwaters of the Colorado River (also known as the River) and is an important source of snowmelt runoff to the River. Groundwater discharge also is an important source of water in the River and its tributaries, with estimates ranging from 21 to 58 percent of streamflow in the upper basin. Planning for the sustainable management of the Colorado River in future climates requires an understanding of the Upper Colorado River Basin groundwater system. This report documents input datasets for a Soil-Water Balance groundwater recharge model that was developed for the Upper Colorado River Basin.

  17. Nearshore thermal gradients of the Colorado River near the Little Colorado River confluence, Grand Canyon National Park, Arizona, 2010

    Science.gov (United States)

    Ross, Rob; Grams, Paul E.

    2013-01-01

    Construction and operation of Glen Canyon Dam has dramatically impacted the flow of the Colorado River through Glen, Marble, and Grand Canyons. Extremes in both streamflow and water temperature have been suppressed by controlled releases from the dam. Trapping of sediment in Lake Powell, the reservoir formed by Glen Canyon Dam, has also dramatically reduced the supply of suspended sediment entering the system. These changes have altered the riverine ecosystem and the habitat of native species, including fish such as the endangered humpback chub (Gila cypha). Most native fish are adapted to seasonally warm water, and the continuous relatively cold water released by the dam is one of the factors that is believed to limit humpback chub growth and survival. While average mainstem temperatures in the Colorado River are well documented, there is limited understanding of temperatures in the nearshore environments that fish typically occupy. Four nearshore geomorphic unit types were studied between the confluence of the Colorado and Little Colorado Rivers and Lava Canyon in the summer and fall of 2010, for study periods of 10 to 27 days. Five to seven sites were studied during each interval. Persistent thermal gradients greater than the 0.2 °C accuracy of the instruments were not observed in any of the sampled shoreline environments. Temperature gradients between the shoreline and mainstem on the order of 4 °C, believed to be important to the habitat-seeking behavior of native or nonnative fishes, were not detected.

  18. It takes more than water: Restoring the Colorado River Delta

    Science.gov (United States)

    Pitt, Jennifer; Kendy, Eloise; Schlatter, Karen; Hinojosa-Huertaf, Osvel; Flessa, Karl W.; Shafroth, Patrick B.; Ramirez-Hernandez, Jorge; Nagler, Pamela L.; Glenn, Edward P.

    2017-01-01

    Environmental flows have become important tools for restoring rivers and associated riparian ecosystems (Arthington, 2012; Glenn et al., 2017). In March 2014, the United States and Mexico initiated a bold effort in restoration, delivering from Morelos Dam a “pulse flow” of water into the Colorado River in its delta for the purpose of learning about its environmental effects (Flessa et al., 2013; Bark et al., 2016). Specifically, scientists evaluated whether the pulse flow, albeit miniscule compared to historical floods, could provide the ecological functions needed to establish native, flood-dependent vegetation to restore natural habitat along the riparian corridor.

  19. Environmental Setting and Implications on Water Quality, Upper Colorado River Basin, Colorado and Utah

    Science.gov (United States)

    Apodaca, Lori E.; Driver, Nancy E.; Stephens, Verlin C.; Spahr, Norman E.

    1995-01-01

    The Upper Colorado River Basin in Colorado and Utah is 1 of 60 study units selected for water-quality assessment as part of the U.S. Geological Survey's National Water-Quality Assessment program, which began full implementation in 1991. Understanding the environmental setting of the Upper Colorado River Basin study unit is important in evaluating water-quality issues in the basin. Natural and human factors that affect water quality in the basin are presented, including an overview of the physiography, climatic conditions, general geology and soils, ecoregions, population, land use, water management and use, hydrologic characteristics, and to the extent possible aquatic biology. These factors have substantial implications on water-quality conditions in the basin. For example, high concentrations of dissolved solids and selenium are present in the natural background water conditions of surface and ground water in parts ofthe basin. In addition, mining, urban, and agricultural land and water uses result in the presence of certain constituents in the surface and ground water of the basin that can detrimentally affect water quality. The environmental setting of the study unit provides a framework of the basin characteristics, which is important in the design of integrated studies of surface water, ground water, and biology.

  20. Selenium impacts on razorback sucker, Colorado River, Colorado: II. Eggs

    Science.gov (United States)

    Hamilton, S.J.; Holley, K.M.; Buhl, K.J.; Bullard, F.A.

    2005-01-01

    Effects on hatching and development of fertilized eggs in adult razorback sucker (Xyrauchen texanus) exposed to selenium in flooded bottomland sites near Grand Junction, Colorado, were determined. After 9 months exposure, fish were collected and induced to spawn and eggs collected for inorganic element analyses. A 9-day egg study was conducted with five spawns from Horsethief ponds, six spawns from Adobe Creek channel, and four spawns from North Pond using a reference water and site waters. Selenium concentrations in eggs were 6.5 ??g/g from Horsethief, 46 ??g/g from Adobe Creek, 38 ??g/g from North Pond, and 6.0 ??g/g from brood stock. Eggs from young adults had a smaller diameter and higher moisture content than brood stock. There were no differences among the four sources in viability, survival, hatch, hatchability, or mortality of deformed embryos or larvae. Adobe Creek larvae had more deformed embryos in eggs held in site water than held in reference water. There were significant negative correlations between selenium concentrations in adult muscle plugs and percent hatch, egg diameter, and deformities in embryos. Results from this study suggest that selenium contamination in parts of the upper basin of the Colorado River should be a major concern to recovery efforts for endangered fish.

  1. Selenium impacts on razorback sucker, Colorado River, Colorado II. Eggs.

    Science.gov (United States)

    Hamilton, Steven J; Holley, Kathy M; Buhl, Kevin J; Bullard, Fern A

    2005-05-01

    Effects on hatching and development of fertilized eggs in adult razorback sucker (Xyrauchen texanus) exposed to selenium in flooded bottomland sites near Grand Junction, Colorado, were determined. After 9 months exposure, fish were collected and induced to spawn and eggs collected for inorganic element analyses. A 9-day egg study was conducted with five spawns from Horsethief ponds, six spawns from Adobe Creek channel, and four spawns from North Pond using a reference water and site waters. Selenium concentrations in eggs were 6.5 microg/g from Horsethief, 46 microg/g from Adobe Creek, 38 microg/g from North Pond, and 6.0 microg/g from brood stock. Eggs from young adults had a smaller diameter and higher moisture content than brood stock. There were no differences among the four sources in viability, survival, hatch, hatchability, or mortality of deformed embryos or larvae. Adobe Creek larvae had more deformed embryos in eggs held in site water than held in reference water. There were significant negative correlations between selenium concentrations in adult muscle plugs and percent hatch, egg diameter, and deformities in embryos. Results from this study suggest that selenium contamination in parts of the upper basin of the Colorado River should be a major concern to recovery efforts for endangered fish.

  2. Geomorphic change and sediment transport during a small artificial flood in a transformed post-dam delta: The Colorado River delta, United States and Mexico

    Science.gov (United States)

    Mueller, Erich R.; Schmidt, John C.; Topping, David J.; Shafroth, Patrick B.; Rodríguez-Burgueño, Jesús Eliana; Ramírez-Hernández, Jorge; Grams, Paul E.

    2016-01-01

    The Colorado River delta is a dramatically transformed landscape. Major changes to river hydrology and morpho-dynamics began following completion of Hoover Dam in 1936. Today, the Colorado River has an intermittent and/or ephemeral channel in much of its former delta. Initial incision of the river channel in the upstream ∼50 km of the delta occurred in the early 1940s in response to spillway releases from Hoover Dam under conditions of drastically reduced sediment supply. A period of relative quiescence followed, until the filling of upstream reservoirs precipitated a resurgence of flows to the delta in the 1980s and 1990s. Flow releases during extreme upper basin snowmelt in the 1980s, flood flows from the Gila River basin in 1993, and a series of ever-decreasing peak flows in the late 1990s and early 2000s further incised the upstream channel and caused considerable channel migration throughout the river corridor. These variable magnitude post-dam floods shaped the modern river geomorphology. In 2014, an experimental pulse-flow release aimed at rejuvenating the riparian ecosystem and understanding hydrologic dynamics flowed more than 100 km through the length of the delta’s river corridor. This small artificial flood caused localized meter-scale scour and fill of the streambed, but did not cause further incision or significant bank erosion because of its small magnitude. Suspended-sand-transport rates were initially relatively high immediately downstream from the Morelos Dam release point, but decreasing discharge from infiltration losses combined with channel widening downstream caused a rapid downstream reduction in suspended-sand-transport rates. A zone of enhanced transport occurred downstream from the southern U.S.-Mexico border where gradient increased, but effectively no geomorphic change occurred beyond a point 65 km downstream from Morelos Dam. Thus, while the pulse flow connected with the modern estuary, deltaic sedimentary processes were not

  3. Assessing Vulnerability under Uncertainty in the Colorado River Basin: The Colorado River Basin Water Supply and Demand Study

    Science.gov (United States)

    Jerla, C.; Adams, P.; Butler, A.; Nowak, K.; Prairie, J. R.

    2013-12-01

    Spanning parts of the seven states, of Arizona, California, Colorado, New Mexico, Nevada, Utah, and Wyoming, the Colorado River is one of the most critical sources of water in the western United States. Colorado River allocations exceed the long-term supply and since the 1950s, there have been a number of years when the annual water use in the Colorado River Basin exceeded the yield. The Basin is entering its second decade of drought conditions which brings challenges that will only be compounded if projections of climate change are realized. It was against this backdrop that the Colorado River Basin Water Supply and Demand Study was conducted. The Study's objectives are to define current and future imbalances in the Basin over the next 50 years and to develop and analyze adaptation and mitigation strategies to resolve those imbalances. Long-term planning in the Basin involves the integration of uncertainty with respect to a changing climate and other uncertainties such as future demand and how policies may be modified to adapt to changing reliability. The Study adopted a scenario planning approach to address this uncertainty in which thousands of scenarios were developed to encompass a wide range of plausible future water supply and demand conditions. Using Reclamation's long-term planning model, the Colorado River Simulation System, the reliability of the system to meet Basin resource needs under these future conditions was projected both with and without additional future adaptation strategies in place. System reliability metrics were developed in order to define system vulnerabilities, the conditions that lead to those vulnerabilities, and sign posts to indicate if the system is approaching a vulnerable state. Options and strategies that reduce these vulnerabilities and improve system reliability were explored through the development of portfolios. Four portfolios, each with different management strategies, were analyzed to assess their effectiveness at

  4. Colorado River Basin Hover Dam - Review of Flood Control Regulation.

    Science.gov (United States)

    1982-07-01

    Percichthyidae Striped bass 1ile sxiiis Pocilldae Mosquito fish Cainbusia affnus Sailfin mollie Poecilia latipin a Mexican mollie Poecila mexicana Salmonidae...Colorado River Basin Progress Report No. 8, 195 pp. Vitt, L.J. and R.D. Ohmart, 1978. Herpetofauna of the Lower Colorado River: Davis Dam to the

  5. Climate Variability: Adaptation Strategies for Colorado River Management

    Science.gov (United States)

    Fulp, T. J.; Prairie, J. R.

    2008-12-01

    The importance of the Colorado River system to the western United States and the Republic of Mexico is well documented. Much has been written recently in response to the lingering drought and increasing demands on the system. Questions such as "has the river run out of water?", "how low can it go?", and "will Lake Mead go dry?" express the concern that the river system will be hard-pressed to continue to meet future demands, particularly if droughts tend toward increased magnitudes and longer durations. Reservoirs on the main stream of the Colorado River are managed by the Bureau of Reclamation (Reclamation), on behalf of the Secretary of the U.S. Department of the Interior (Secretary). Over 80% of the 60 million acre-feet of storage capacity is contained in Lake Powell and Lake Mead, large reservoirs that are located in each of the sub-basins (Upper Basin and Lower Basin) defined in the 1922 Colorado River Compact. In response to the worst drought conditions in approximately one hundred years of recorded history and the lack of specific operational guidelines for operation of Lake Powell and Lake Mead for drought and low reservoir conditions, the Secretary adopted new operational guidelines in December 2007 that will be used for an interim period (through 2026). The Interim Guidelines were the result of an intense, three-year effort in accordance with the National Environmental Policy Act of 1969 (NEPA). Several alternative operational rules were compared with respect to future potential impacts to Colorado River resources, including lake levels, water delivery, hydropower production, water quality, recreation, and fish and wildlife and published in an Environmental Impact Statement (EIS). Due to the large uncertainty regarding future inflows into the system, particularly in a changing climate, these comparisons were presented in probabilistic terms in order to assess the risk of key events (e.g., the timing and magnitude of water shortages). Because it is

  6. Input Digital Datasets for the Soil-Water Balance Groundwater Recharge Model of the Upper Colorado River Basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The Colorado River and its tributaries supply water to more than 35 million people in the United States and 3 million people in Mexico, irrigating more than 4.5...

  7. Colorado River Sewer System Joint Venture to Upgrade Wastewater System

    Science.gov (United States)

    SAN FRANCISCO -Today, the Colorado River Sewer System Joint Venture, located in Parker, Ariz. entered into an agreement with the EPA to upgrade their wastewater treatment system to meet stringent water quality standards. The cost of the upgrade is ap

  8. Corbiculae fluminea as a bioindicator on the Lower Colorado River

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Tissue samples from Asiatic clam (Corbimla fluminea) from the lower Colorado River were analyzed for trace element concentrations. Selenium and arsenic were elevated...

  9. Point Sources of Emerging Contaminants Along the Colorado River Basin: Impact on Water Use and Reuse in the Arid Southwest

    Science.gov (United States)

    Emerging contaminants (ECs) (e.g., pharmaceuticals, illicit drugs, personal care products) have been detected in waters across the United States. The objective of this study was to evaluate point sources of ECs along the Colorado River, from the headwaters in Colorado to the Gulf...

  10. Bureau of Reclamation-Lower Colorado River Management Plan for the Yuma Clapper Rail

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Presently there are just over 4,200 acres of cattail/bulrush along the lower Colorado River (LCR) in the United States, most of which is managed by the U.S. Fish and...

  11. Colorado River fish monitoring in Grand Canyon, Arizona; 2002–14 humpback chub aggregations

    Science.gov (United States)

    Persons, William R.; Van Haverbeke, David R.; Dodrill, Michael J.

    2017-01-31

    The humpback chub (Gila cypha) is an endangered cyprinid species endemic to the Colorado River. The largest remaining population of the species spawns and rears in the Little Colorado River in Grand Canyon. Construction and operation of Glen Canyon Dam has altered the main-stem Colorado River in Glen and Grand Canyons. Cold, clear water releases from the dam result in a river that is generally unsuitable for successful humpback chub reproduction. During the early 1990s, nine locations within the main-stem Colorado River were identified as humpback chub aggregations—areas with a consistent and disjunct group of fish with no significant exchange of individuals with other aggregations. We monitored main-stem Colorado River aggregations of humpback chub in Grand Canyon during 2010 to 2014 and compared our results to previous investigations. Relative abundance, as described by catch per unit effort (fish per hour) of adult humpback chub at most main-stem aggregations, generally increased from the 1990s to 2014. In addition, distribution of humpback chub in the main-stem Colorado River has increased since the 1990s. Movement of humpback chub between the Little Colorado River and other aggregations likely adds fish to those aggregations. There is clear evidence of reproduction near the 30-Mile aggregation, and reproduction at Middle Granite Gorge and downstream seems likely based on catches of gravid fish and captures of very young fish, especially during relatively warm water releases from Glen Canyon Dam, 2004 to 2011. Humpback chub relative abundance at Shinumo and Havasu Creek inflows increased following translocations of young humpback chub starting in 2009. In light of this information, we modify the original nine aggregations, combining two previously separate aggregations and dropping two locations to form six distinct aggregations of humpback chub. Trends in humpback chub abundance at main-stem aggregations, relative to management actions (for example

  12. Updated streamflow reconstructions for the Upper Colorado River Basin

    Science.gov (United States)

    Woodhouse, C.A.; Gray, S.T.; Meko, D.M.

    2006-01-01

    Updated proxy reconstructions of water year (October-September) streamflow for four key gauges in the Upper Colorado River Basin were generated using an expanded tree ring network and longer calibration records than in previous efforts. Reconstructed gauges include the Green River at Green River, Utah; Colorado near Cisco, Utah; San Juan near Bluff, Utah; and Colorado at Lees Ferry, Arizona. The reconstructions explain 72-81% of the variance in the gauge records, and results are robust across several reconstruction approaches. Time series plots as well as results of cross-spectral analysis indicate strong spatial coherence in runoff variations across the subbasins. The Lees Ferry reconstruction suggests a higher long-term mean than previous reconstructions but strongly supports earlier findings that Colorado River allocations were based on one of the wettest periods in the past 5 centuries and that droughts more severe than any 20th to 21st century event occurred in the past. Copyright 2006 by the American Geophysical Union.

  13. Colorado River Wildlife Management Area (Green River Easements) [Land Status Map: Sheet 1 of 2

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This map was produced by the Division of Realty to depict landownership at Colorado River Wildlife Management Area. It was generated from rectified aerial...

  14. A Dreissena Risk Assessment for the Colorado River Ecosystem

    Science.gov (United States)

    Kennedy, Theodore A.

    2007-01-01

    Executive Summary Nonnative zebra and quagga mussels (Dreissena polymorpha and Dreissena bugensis, respectively; see photo above) were accidentally introduced to the Great Lakes in the 1980s and subsequently spread to watersheds of the Eastern United States (Strayer and others, 1999). The introduction of Dreissena mussels has been economically costly and has had large and far-reaching ecological impacts on these systems. Quagga mussels were found in Lakes Mead and Havasu in January 2007. Given the likelihood that quagga mussels and, eventually, zebra mussels will be introduced to Lake Powell and the Colorado River at Lees Ferry, it is important to assess the risks that introduction of Dreissena mussels pose to the Colorado River ecosystem (here defined as the segment of river from just below Glen Canyon Dam to Diamond Creek; hereafter CRE). In this report, I assess three different types of risks associated with Dreissena and the CRE: (1) the risk that Dreissena will establish at high densities in the CRE, (2) the risk of ecological impacts should Dreissena establish at high densities in the CRE or in Lake Powell, and (3) the risk that Dreissena will be introduced to tributaries of the CRE. The risk of Dreissena establishing within the CRE is low, except for the Lees Ferry tailwater reach where the risk appears high. Dreissena are unlikely to establish at high densities within the CRE or its tributaries because of high suspended sediment, high ratios of suspended inorganic:organic material, and high water velocities, all of which interfere with the ability of Dreissena to effectively filter feed. The rapids of Grand Canyon may represent a large source of mortality to larval Dreissena, which would limit their ability to disperse and colonize downstream reaches of the CRE. In contrast, conditions within the Lees Ferry tailwater generally appear suitable for Dreissena establishment, with the exception of high average water velocity. If Dreissena establish within the

  15. 76 FR 77549 - Colorado River Indian Tribes-Amendment to Health & Safety Code, Article 2. Liquor

    Science.gov (United States)

    2011-12-13

    ... Bureau of Indian Affairs Colorado River Indian Tribes--Amendment to Health & Safety Code, Article 2... amendment to the Colorado River Tribal Health and Safety Code, Article 2. Liquor, Section 2-403(12). The... liquor ordinances for the purpose of regulating liquor transactions in Indian country. The Colorado...

  16. Snow water equivalent interpolation for the Colorado River Basin from snow telemetry (SNOTEL) data

    OpenAIRE

    Fassnacht, SR; Dressler, KA; Bales, RC

    2003-01-01

    Inverse weighted distance and regression nonexact techniques were evaluated for interpolating methods snow water equivalent (SWE) across the entire Colorado River Basin of the western United States. A 1-km spacing was used for the gridding of snow telemetry (SNOTEL) measurements for the years 1993, 1998, and 1999, which on average, represented higher than average, average, and lower than average snow years. Because of the terrain effects, the regression techniques (hypsometric elevation and m...

  17. Hydrology and management of Lakes Mead and Mohave within the Colorado River Basin: Chapter 3 in A synthesis of aquatic science for management of Lakes Mead and Mohave

    Science.gov (United States)

    Holdren, G. Chris; Tietjen, Todd; Turner, Kent; Miller, Jennell M.

    2012-01-01

    The Colorado River Basin covers parts of seven States: Colorado, Wyoming, Utah, New Mexico, Nevada, Arizona, and California; at 1,450 mi (2,333.5 km) in length, the Colorado River is the seventh longest river in the United States (fig. 3-1). The Bureau of Reclamation has the responsibility for management of this system, in coordination with the seven basin States, within a complex framework of law, regulations, compact, treaty, and policies often referred to collectively as the “Law of the River.” Lake Mead is a critical component of the overall Colorado River management, providing the capacity to store almost 2 years of the average runoff of the river.

  18. Assessment of surface-water quantity and quality, Eagle River watershed, Colorado, 1947-2007

    Science.gov (United States)

    Williams, Cory A.; Moore, Jennifer L.; Richards, Rodney J.

    2011-01-01

    From the early mining days to the current tourism-based economy, the Eagle River watershed (ERW) in central Colorado has undergone a sequence of land-use changes that has affected the hydrology, habitat, and water quality of the area. In 2000, the USGS, in cooperation with the Colorado River Water Conservation District, Eagle County, Eagle River Water and Sanitation District, Upper Eagle Regional Water Authority, Colorado Department of Transportation, City of Aurora, Town of Eagle, Town of Gypsum, Town of Minturn, Town of Vail, Vail Resorts, City of Colorado Springs, Colorado Springs Utilities, and Denver Water, initiated a retrospective analysis of surface-water quantity and quality in the ERW.

  19. Effects of climate change and land use on water resources in the Upper Colorado River Basin

    Science.gov (United States)

    Belnap, Jayne; Campbell, D.H.

    2011-01-01

    The health of the Colorado River watershed is critical to the socioeconomic and ecosystem well-being of the Southwestern United States. Water in springs, streams, and rivers supports a range of aquatic and riparian ecosystems that contain many endangered species. Terrestrial habitats support a wide array of plants and wildlife. In addition, this region is enjoyed by millions of people annually for its recreational and esthetic opportunities. The Colorado River provides water for about 25 million people and is used to irrigate 2.5 million acres of farmland. However, competition for this water is expected to increase as human populations dependent on this water are projected to increase to 38 million by 2020. Climate change is expected to further exacerbate water issues in this region. Drought in the Southwest during 2000-04, caused by both reduced precipitation and a series of the hottest years on record, resulted in streamflows lower than during the 1930s Dust Bowl or the 1950s. Increased temperatures alone are a major factor in reducing surface-water flows in this region. For instance, precipitation received during the winter of 2005 was at the 100-year average. However, low soil moisture and high January-July temperatures resulted in flows that were only 75 percent of average. Climate models predict future warmer temperatures and reduced precipitation in the Upper Colorado River Basin (UCRB), which would reduce water available to humans and ecosystems.

  20. Warming may create substantial water supply shortages in the Colorado River basin

    Science.gov (United States)

    McCabe, G.J.; Wolock, D.M.

    2007-01-01

    The high demand for water, the recent multiyear drought (1999-2007), and projections of global warming have raised questions about the long-term sustainability of water supply in the southwestern United States. In this study, the potential effects of specific levels of atmospheric warming on water-year streamflow in the Colorado River basin are evaluated using a water-balance model, and the results are analyzed within the context of a multi-century tree-ring reconstruction (1490-1998) of streamflow for the basin. The results indicate that if future warming occurs in the basin and is not accompanied by increased precipitation, then the basin is likely to experience periods of water supply shortages more severe than those inferred from the longterm historical tree-ring reconstruction. Furthermore, the modeling results suggest that future warming would increase the likelihood of failure to meet the water allocation requirements of the Colorado River Compact.

  1. The Three Colorado Rivers: Comparing the Physical, Legal, and Economic Allocation of a Shared River

    Science.gov (United States)

    Rushforth, R.; Ruddell, B. L.

    2015-12-01

    : For many rivers, the legal allocation of surface water was settled decades ago. The process of apportioning surface water between multiple stakeholders is an arduous process with opposing interests competing for scarce resources. The political capital spent initially allocating a river often cannot be regained, stymieing future attempts for re-allocation. The Colorado River Compact (Compact), signed in 1922, has been "the law of the river" for over 90 years. Since its signing, the Colorado River Basin (CRB) population has increased tenfold, while average river flows have decreased due to threats unforeseeable to Compact signers, such as global climate change. Water sharing agreements, like the Compact, legally re-allocate physical river flows; however, water is increasingly shared through trade rather than aqueducts. Virtual water, or the water embodied by a good or service, is a trade adaption to resource scarcity, namely water and land. This study presents findings of a virtual water complement to the Compact. The goal of this study is to determine how the legal allocation of physical water resources are re-allocated as virtual water via economic trade in a shared river basin. Results are presented by at the sub-basin, state, and county-level, showing the geographic origin and destination of virtual water from CRB states and the Upper and Lower basins. A water stress index is calculated to show the indirect water stress of Colorado River water resources and network statistics are employed to rank the importance of virtual water sources in the CRB.

  2. Oil shale resources in the Eocene Green River Formation, Greater Green River Basin, Wyoming, Colorado, and Utah

    Science.gov (United States)

    ,

    2011-01-01

    The U.S. Geological Survey (USGS) recently completed a comprehensive assessment of in-place oil in oil shales in the Eocene Green River in the Greater Green River Basin, Wyoming, Colorado, and Utah. This CD-ROM includes reports, data, and an ArcGIS project describing the assessment. A database was compiled that includes about 47,000 Fischer assays from 186 core holes and 240 rotary drill holes. Most of the oil yield data were analyzed by the former U.S. Bureau of Mines oil shale laboratory in Laramie, Wyoming, and some analyses were made by private laboratories. Location data for 971 Wyoming oil-shale drill holes are listed in a spreadsheet and included in the CD-ROM. Total in-place resources for the three assessed units in the Green River Formation are: (1) Tipton Shale Member, 362,816 million barrels of oil (MMBO), (2) Wilkins Peak Member, 704,991 MMBO, and (3) LaClede Bed of the Laney Member, 377,184 MMBO, for a total of 1.44 trillion barrels of oil in place. This compares with estimated in-place resources for the Piceance Basin of Colorado of 1.53 trillion barrels and estimated in-place resources for the Uinta Basin of Utah and Colorado of 1.32 trillion barrels.

  3. Evaluating natural gas development impacts on stream ecosystems in an Upper Colorado River watershed

    Science.gov (United States)

    Holloway, J. M.; Bern, C.; Schmidt, T. S.; McDougal, R. R.; Clark, M. L.; Stricker, C. A.; Wolf, R. E.

    2011-12-01

    Oil and gas development in the western United States is increasingly placing at odds the management of two critical natural resources: fossil fuels and water. Muddy Creek, part of the Upper Colorado River watershed, is a semi-arid catchment in a sagebrush steppe ecosystem. Muddy Creek flows throughout the year and includes both perennial and ephemeral tributaries. Primary land use includes livestock grazing, oil and gas development, and recreational activities. A multi-discipline study has been initiated to determine potential impacts of the projected increase of coal bed natural gas development. Hundreds of permits for drilling co-produced waters have been issued, but low energy prices have slowed development. A watershed assessment was conducted in 2010 to determine areas within the watershed that are more susceptible to mobilization of trace elements that occur in soils forming on marine shales. Soil, stream sediment, and water samples were collected and analyzed for major elements and a suite of trace elements, with arsenic and selenium identified as potential elements of concern. A study of benthic and riparian invertebrates is being conducted to evaluate the uptake of these elements into the food web at targeted locations in the Muddy Creek watershed. Continued work will address sources of salinity to Muddy Creek, and ultimately to the Upper Colorado River. Impacts from energy development can include mobilization of naturally occurring sulfate salts through soil disturbance. Formation waters currently discharged to the surface from two failed wells within the watershed will be evaluated for their contribution to salinity, as well as dissolved organic carbon, nitrogen species, and trace elements, to the Upper Colorado River. Upon completion, this study will provide a baseline that can assist in land-use management decisions as oil and gas extraction expands in the Upper Colorado River watershed.

  4. 76 FR 6819 - Agency Information Collection Activities: Proposed Information Collection; Colorado River...

    Science.gov (United States)

    2011-02-08

    ... River Valuation Survey AGENCY: National Park Service. ACTION: Notice; request for comments. SUMMARY: We..., health, and safety. Other federal rules (National Environmental Policy Act, 1969 and NPS guidelines...: Colorado River Valuation Survey. Type of Request: New. Affected Public: General public;...

  5. Community-based restoration of desert wetlands: the case of the Colorado River delta

    Science.gov (United States)

    Osvel Hinojosa-Huerta; Mark Briggs; Yamilett Carrillo-Guerroro; Edward P. Glenn; Miriam Lara-Flores; Martha Roman-Rodriguez

    2005-01-01

    Wetland areas have been drastically reduced through the Pacific Flyway and the Sonoran Desert, with severe consequences for avian populations. In the Colorado River delta, wetlands have been reduced by 80 percent due to water management practices in the Colorado River basin. However, excess flows and agricultural drainage water has restored some areas, providing...

  6. 78 FR 58344 - Proposed Information Collection: Colorado River Total Value Survey

    Science.gov (United States)

    2013-09-23

    ... National Park Service Proposed Information Collection: Colorado River Total Value Survey AGENCY: National... Colorado River riparian resource, and on alternative flow release scenarios from Glen Canyon Dam designed to protect canyon flora and fauna. The final survey will provide information for the...

  7. 78 FR 66267 - Safety Zone; HITS Triathlon Series; Colorado River; Lake Havasu, AZ

    Science.gov (United States)

    2013-11-05

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; HITS Triathlon Series; Colorado River; Lake... establishing a safety zone upon the navigable waters of the Colorado River in support of the HITS Triathlon.... is sponsoring the HITS Triathlon Series, which will involve 1,200 swimmers transiting North...

  8. An Analysis of The Early Development and Protection of the Colorado River

    Institute of Scientific and Technical Information of China (English)

    Zhao Qian

    2009-01-01

    This thesis attempts an environmental analysis of the Colorado River in Southwest America.and examines the early issues of economic development and environmental protection on the Colorado River Basin from a historical perspective.The thesis first provides a brief description of the geography of the Colorado River,paying special attention to the early exploration of the Colorado River by Native Americans and later European colonizers as well as their different attitudes toward nature.Then the thesis looks at the forces of economic development and nature preservation in the progressive era against the arid setting of the Southwest.In the conclusion,the author demonstrates the importance and necessity of the environmental protection of the Colorado River in the beginning period of the America West.

  9. Hypothesis of historical effects from selenium on endangered fish in the Colorado River basin

    Science.gov (United States)

    Hamilton, S.J.

    1999-01-01

    Anthropogenic selenium contamination of aquatic ecosystems was first associated with cooling reservoirs of coal-fired power plants in the late 1970s, and later with drainage water from agricultural irrigation activities in the 1980s. In the 1990s, selenium contamination has been raised as a concern in the recovery of currently endangered fish in the Colorado River system. Widespread contamination from seleniferous drain waters from agriculture has been documented in the upper and lower Colorado River basins. Historically, irrigation started in the upper Colorado River basin in the late 1880s. In the 1930s, selenium concentrations in various drains, tributaries, and major rivers in the upper and lower Colorado River basins were in the 100s and 1000s of ??g/L. Native fish inhabiting large rivers such as the Colorado pikeminnow and razorback sucker were abundant before 1890, but became rare after 1910 to 1920, before the influence of mainstem reservoirs in the upper and lower Colorado River. A hypothesis is presented that selenium contamination of the tributaries and major rivers of the Colorado River basin in the 1890 to 1910 period caused the decline of the endangered fish and continues to inhibit their recovery. ?? 1999 by ASP.

  10. Dating of Pliocene Colorado River sediments: Implications for cosmogenic burial dating and the evolution of the lower Colorado River

    Science.gov (United States)

    Howard, Keith A.; Matmon, Ari; Stock, Greg M.; Granger, Darryl E.

    2017-01-01

    We applied cosmogenic 26Al/10Be burial dating to sedimentary deposits of the ancestral Colorado River. We compared cosmogenic burial ages of sediments to the age of an independently well-dated overlying basalt flow at one site, and also applied cosmogenic burial dating to sediments with less precise independent age constraints. All dated gravels yielded old ages that suggest several episodes of sediment burial over the past ∼5.3 m.y. Comparison of burial ages to the overlying 4.4 Ma basalt yielded good agreement and suggests that under the most favorable conditions, cosmogenic burial dating can extend back 4–5 m.y. In contrast, results from other sites with more broadly independent age constraints highlight the complexities inherent in burial dating; these complexities arise from unknown and complicated burial histories, insufficient shielding, postburial production of cosmogenic isotopes by muons, and unknown initial 26Al/10Be ratios. Nevertheless, and in spite of the large range of burial ages and large uncertainties, we identify samples that provide reasonable burial age constraints on the depositional history of sediment along the lower ancestral Colorado River. These samples suggest possible sediment deposition and burial at ca. 5.3, 4.7, and 3.6 Ma.Our calculated basinwide erosion rate for sediment transported by the modern Colorado River (∼187 mm k.y.−1) is higher than the modern erosion rates inferred from the historic sediment load (80–100 mm k.y.−1). In contrast, basinwide paleo-erosion rates calculated from Pliocene sediments are all under 40 mm k.y.−1 The comparatively lower denudation rates calculated for the Pliocene sediment samples are surprising given that the sampled time intervals include significant Pliocene aggradation and may include much incision of the Grand Canyon and its tributaries. This conflict may arise from extensive storage of sediment along the route of the Colorado River, slower paleobedrock erosion, or the

  11. Dating of Pliocene Colorado River sediments: implications for cosmogenic burial dating and the evolution of the lower Colorado River

    Science.gov (United States)

    Matmon, Ari; Stock, Greg M.; Granger, Darryl E.; Howard, Keith A.

    2011-01-01

    We applied cosmogenic 26Al/10Be burial dating to sedimentary deposits of the ancestral Colorado River. We compared cosmogenic burial ages of sediments to the age of an independently well-dated overlying basalt flow at one site, and also applied cosmogenic burial dating to sediments with less precise independent age constraints. All dated gravels yielded old ages that suggest several episodes of sediment burial over the past ∼5.3 m.y. Comparison of burial ages to the overlying 4.4 Ma basalt yielded good agreement and suggests that under the most favorable conditions, cosmogenic burial dating can extend back 4–5 m.y. In contrast, results from other sites with more broadly independent age constraints highlight the complexities inherent in burial dating; these complexities arise from unknown and complicated burial histories, insufficient shielding, postburial production of cosmogenic isotopes by muons, and unknown initial 26Al/10Be ratios. Nevertheless, and in spite of the large range of burial ages and large uncertainties, we identify samples that provide reasonable burial age constraints on the depositional history of sediment along the lower ancestral Colorado River. These samples suggest possible sediment deposition and burial at ca. 5.3, 4.7, and 3.6 Ma. Our calculated basinwide erosion rate for sediment transported by the modern Colorado River (∼187 mm k.y.−1) is higher than the modern erosion rates inferred from the historic sediment load (80–100 mm k.y.−1). In contrast, basinwide paleo-erosion rates calculated from Pliocene sediments are all under 40 mm k.y.−1 The comparatively lower denudation rates calculated for the Pliocene sediment samples are surprising given that the sampled time intervals include significant Pliocene aggradation and may include much incision of the Grand Canyon and its tributaries. This conflict may arise from extensive storage of sediment along the route of the Colorado River, slower paleobedrock erosion, or the inclusion

  12. Response of Colorado river runoff to dust radiative forcing in snow

    Science.gov (United States)

    Painter, T.H.; Deems, J.S.; Belnap, J.; Hamlet, A.F.; Landry, C.C.; Udall, B.

    2010-01-01

    The waters of the Colorado River serve 27 million people in seven states and two countries but are overallocated by more than 10% of the river's historical mean. Climate models project runoff losses of 7-20% from the basin in this century due to human-induced climate change. Recent work has shown however that by the late 1800s, decades prior to allocation of the river's runoff in the 1920s, a fivefold increase in dust loading from anthropogenically disturbed soils in the southwest United States was already decreasing snow albedo and shortening the duration of snow cover by several weeks. The degree to which this increase in radiative forcing by dust in snow has affected timing and magnitude of runoff from the Upper Colorado River Basin (UCRB) is unknown. Hereweuse the Variable Infiltration Capacity model with postdisturbance and predisturbance impacts of dust on albedo to estimate the impact on runoff from the UCRB across 1916-2003. We find that peak runoff at Lees Ferry, Arizona has occurred on average 3 wk earlier under heavier dust loading and that increases in evapotranspiration from earlier exposure of vegetation and soils decreases annual runoff by more than 1.0 billion cubic meters or ???5% of the annual average. The potential to reduce dust loading through surface stabilization in the deserts and restore more persistent snow cover, slow runoff, and increase water resources in the UCRB may represent an important mitigation opportunity to reduce system management tensions and regional impacts of climate change.

  13. Development of streamflow projections under changing climate conditions over Colorado River basin headwaters

    OpenAIRE

    Miller, W. P.; T. C. Piechota; Gangopadhyay, S.; T. Pruitt

    2011-01-01

    The current drought over the Colorado River Basin has raised concerns that the US Department of the Interior, Bureau of Reclamation (Reclamation) may impose water shortages over the lower portion of the basin for the first time in history. The guidelines that determine levels of shortage are affected by relatively short-term (3 to 7 month) forecasts determined by the Colorado Basin River Forecast Center (CBRFC) using the National Weather Service (NWS) River Forecasting Syste...

  14. An Application of Advanced Ensemble Streamflow Prediction Methods to Assess Potential Impacts of the 2015 - 2016 ENSO Event over the Colorado River Basin

    Science.gov (United States)

    Miller, W. P.; Lamb, K. W.; Piechota, T. C.; Lakshmi, V.; Santos, N. I.; Tootle, G. A.; Kalra, A.; Fayne, J.

    2015-12-01

    Water resource managers throughout the Western United States have struggled with persistent and severe drought since the early 2000s. In the Colorado River Basin, the National Oceanic and Atmospheric Administration's (NOAA's) Colorado Basin River Forecast Center (CBRFC) provides forecasts of water supply conditions to resource managers throughout the basin using Ensemble Streamflow Prediction (ESP) methods that are largely driven by historical observations of temperature and precipitation. Currently, the CBRFC does not have a way to incorporate information from climatic teleconnections such as the El Niño Southern Oscillation (ENSO). ENSO describes warming sea surface temperatures in the Pacific Ocean that typically correlate with cool and wet winter precipitation events in California and the Lower Colorado River Basin during an El Niño event. Past research indicates the potential to identify analog ENSO events to evaluate the impact to reservoir storage in the Colorado River Basin. Current forecasts indicate the potential for one of the strongest El Niño events on record this winter. In this study, information regarding the upcoming ENSO event is used to inform water supply forecasts over the Upper Colorado River Basin. These forecasts are then compared to traditionally derived water supply forecast in an attempt to evaluate the possible impact of the El Niño event to water supply over the Colorado River Basin.

  15. Estimation of salt loads for the Dolores River in the Paradox Valley, Colorado, 1980–2015

    Science.gov (United States)

    Mast, M. Alisa

    2017-07-13

    Regression models that relate total dissolved solids (TDS) concentrations to specific conductance were used to estimate salt loads for two sites on the Dolores River in the Paradox Valley in western Colorado. The salt-load estimates will be used by the Bureau of Reclamation to evaluate salt loading to the river coming from the Paradox Valley and the effect of the Paradox Valley Unit (PVU), a project designed to reduce the salinity of the Colorado River. A second-order polynomial provided the best fit of the discrete data for both sites on the river. The largest bias occurred in samples with elevated sulfate concentrations (greater than 500 milligrams per liter), which were associated with short-duration runoff events in late summer and fall. Comparison of regression models from a period of time before operation began at the PVU and three periods after operation began suggests the relation between TDS and specific conductance has not changed over time. Net salt gain through the Paradox Valley was estimated as the TDS load at the downstream site minus the load at the upstream site. The mean annual salt gain was 137,900 tons per year prior to operation of the PVU (1980–1993) and 43,300 tons per year after the PVU began operation (1997–2015). The difference in annual salt gain in the river between the pre-PVU and post-PVU periods was 94,600 tons per year, which represents a nearly 70 percent reduction in salt loading to the river.

  16. Colorado River fish monitoring in Grand Canyon, Arizona; 2000 to 2009 summary

    Science.gov (United States)

    Makinster, Andrew S.; Persons, William R.; Avery, Luke A.; Bunch, Aaron J.

    2010-01-01

    Long-term fish monitoring in the Colorado River below Glen Canyon Dam is an essential component of the Glen Canyon Dam Adaptive Management Program (GCDAMP). The GCDAMP is a federally authorized initiative to ensure that the primary mandate of the Grand Canyon Protection Act of 1992 to protect resources downstream from Glen Canyon Dam is met. The U.S. Geological Survey's Grand Canyon Monitoring and Research Center is responsible for the program's long-term fish monitoring, which is implemented in cooperation with the Arizona Game and Fish Department, U.S. Fish and Wildlife Service, SWCA Environmental Consultants, and others. Electrofishing and tagging protocols have been developed and implemented for standardized annual monitoring of Colorado River fishes since 2000. In 2009, sampling occurred throughout the river between Lees Ferry and Lake Mead for 38 nights over two trips. During the two trips, scientists captured 6,826 fish representing 11 species. Based on catch-per-unit-effort, salmonids (for example, rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta)) increased eightfold between 2006 and 2009. Flannelmouth sucker (Catostomus latipinnis) catch rates were twice as high in 2009 as in 2006. Humpback chub (Gila cypha) catches were low throughout the 10-year sampling period.

  17. Selected hydrologic data, Yampa River basin and parts of the White River basin, northwestern Colorado and south-central Wyoming

    Science.gov (United States)

    Giles, T.F.; Brogden, Robert E.

    1978-01-01

    Selected hydrologic data are presented from four energy-related projects conducted by the U.S. Geological Survey in the Yampa River basin and parts of the White River basin in northwestern Colorado and south-central Wyoming. Water-quality data during 1974 and 1975 and parts of 1976 for 129 ground-water sites and 119 surface-water sites are tabulated. For most samples, major cations, anions, and trace metals were analyzed. For the same time period, field measurements of specific conductance, temperature, and pH were made on 252 springs and wells. These samplings sites, as well as the locations of 20 climatological stations, 18 snow-course sites, and 43 surface-water gaging stations, are shown on maps. Geologic units that contain coal deposits or supply much of the water used for stock and domestic purposes in the area also are shown on a map. (Woodard-USGS)

  18. Increasing influence of air temperature on upper Colorado River streamflow

    Science.gov (United States)

    Woodhouse, Connie A.; Pederson, Gregory T.; Morino, Kiyomi; McAfee, Stephanie A.; McCabe, Gregory

    2016-01-01

    This empirical study examines the influence of precipitation, temperature, and antecedent soil moisture on upper Colorado River basin (UCRB) water year streamflow over the past century. While cool season precipitation explains most of the variability in annual flows, temperature appears to be highly influential under certain conditions, with the role of antecedent fall soil moisture less clear. In both wet and dry years, when flow is substantially different than expected given precipitation, these factors can modulate the dominant precipitation influence on streamflow. Different combinations of temperature, precipitation, and soil moisture can result in flow deficits of similar magnitude, but recent droughts have been amplified by warmer temperatures that exacerbate the effects of relatively modest precipitation deficits. Since 1988, a marked increase in the frequency of warm years with lower flows than expected, given precipitation, suggests continued warming temperatures will be an increasingly important influence in reducing future UCRB water supplies.

  19. Native fish sanctuaries of the lower Colorado River: Cibola High Levee Pond, Desert Pupfish Pond

    Science.gov (United States)

    Mueller, G.

    2005-01-01

    Historically, the Colorado River was one of the most formidable rivers in the world. Each spring, melting snow from the mountains scoured the desert landscape moving millions of tons of sediment to the sea. The Grand Canyon lays testament to its erosive nature. Summer heat would bring seasonal droughts, reducing the river to a trickle impacting humans, animals, and fish.

  20. Contaminants in Waterbirds, Grackles, and Swallows Nesting on the Lower Colorado River, Arizona, 2000-2001

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Levels and potential effects of organochlorine compounds and metals were assessed in 106 eggs representing nine avian species nesting at four lower Colorado River...

  1. Water classification of the Colorado River Corridor, Grand Canyon, Arizona, 2013—Data

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data area classified maps of water in the Colorado River at a discharge of approximately 227 meters squared/second in Grand Canyon from Glen Canyon Dam to...

  2. Riparian vegetation classification of the Colorado River Corridor, Grand Canyon, Arizona, 2013—Data

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data are classification maps of total riparian vegetation along the Colorado River in Grand Canyon from Glen Canyon Dam to Pearce Ferry in Arizona. The data...

  3. Applications of satellite snow cover in computerized short-term streamflow forecasting. [Conejos River, Colorado

    Science.gov (United States)

    Leaf, C. F.

    1975-01-01

    A procedure is described whereby the correlation between: (1) satellite derived snow-cover depletion and (2) residual snowpack water equivalent, can be used to update computerized residual flow forecasts for the Conejos River in southern Colorado.

  4. Southwestern Riparian Plant Trait Matrix, Colorado River, Grand Canyon, Arizona, 2014 - 2016—Data

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset contains information on the physical traits and environmental tolerances of plant species occurring along the lower Colorado River through Grand Canyon....

  5. Geospatial Dataset of Agricultural Lands in the Upper Colorado River Basin, 2007 - 10

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset represents the extent and spatial distribution of irrigated agricultural lands in the Upper Colorado River Basin for 2007-10. The boundaries in this...

  6. Background Contaminants Evaluation of the Republican River Drainage- Colorado, Kansas, and Nebraska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Republican River Basin is a very large watershed in west-central Kansas, eastern Colorado, Wyoming and southern Nebraska. This study was conducted to determine...

  7. Sustainable water deliveries from the Colorado River in a changing climate

    OpenAIRE

    Barnett, Tim P.; Pierce, David W.

    2009-01-01

    The Colorado River supplies water to 27 million users in 7 states and 2 countries and irrigates over 3 million acres of farmland. Global climate models almost unanimously project that human-induced climate change will reduce runoff in this region by 10–30%. This work explores whether currently scheduled future water deliveries from the Colorado River system are sustainable under different climate-change scenarios. If climate change reduces runoff by 10%, scheduled deliveries will be missed ≈5...

  8. Forecasting the Colorado River Discharge Using an Artificial Neural Network (ANN) Approach

    CERN Document Server

    Mehrkesh, Amirhossein

    2014-01-01

    Artificial Neural Network (ANN) based model is a computational approach commonly used for modeling the complex relationships between input and output parameters. Prediction of the flow rate of a river is a requisite for any successful water resource management and river basin planning. In the current survey, the effectiveness of an Artificial Neural Network was examined to predict the Colorado River discharge. In this modeling process, an ANN model was used to relate the discharge of the Colorado River to such parameters as the amount of precipitation, ambient temperature and snowpack level at a specific time of the year. The model was able to precisely study the impact of climatic parameters on the flow rate of the Colorado River.

  9. Changes in projected spatial and seasonal groundwater recharge in the upper Colorado River Basin

    Science.gov (United States)

    Tillman, Fred; Gangopadhyay, Subhrendu; Pruitt, Tom

    2017-01-01

    The Colorado River is an important source of water in the western United States, supplying the needs of more than 38 million people in the United States and Mexico. Groundwater discharge to streams has been shown to be a critical component of streamflow in the Upper Colorado River Basin (UCRB), particularly during low-flow periods. Understanding impacts on groundwater in the basin from projected climate change will assist water managers in the region in planning for potential changes in the river and groundwater system. A previous study on changes in basin-wide groundwater recharge in the UCRB under projected climate change found substantial increases in temperature, moderate increases in precipitation, and mostly periods of stable or slight increases in simulated groundwater recharge through 2099. This study quantifies projected spatial and seasonal changes in groundwater recharge within the UCRB from recent historical (1950 to 2015) through future (2016 to 2099) time periods, using a distributed-parameter groundwater recharge model with downscaled climate data from 97 Coupled Model Intercomparison Project Phase 5 (CMIP5) climate projections. Simulation results indicate that projected increases in basin-wide recharge of up to 15% are not distributed uniformly within the basin or throughout the year. Northernmost subregions within the UCRB are projected an increase in groundwater recharge, while recharge in other mainly southern subregions will decline. Seasonal changes in recharge also are projected within the UCRB, with decreases of 50% or more in summer months and increases of 50% or more in winter months for all subregions, and increases of 10% or more in spring months for many subregions.

  10. CRevolution 2—Origin and evolution of the Colorado River system, workshop abstracts

    Science.gov (United States)

    : Beard, L. Sue; Karlstrom, Karl E.; Young, Richard A.; Billingsley, George H.

    2011-01-01

    A 2010 Colorado River symposium, held in Flagstaff, Arizona, involved 70 participants who engaged in intense debate about the origin and evolution of the Colorado River system. This symposium, built upon two previous decadal scientific meetings, focused on forging scientific consensus, where possible, while articulating continued controversies regarding the Cenozoic evolution of the Colorado River System and the landscapes of the Colorado Plateau-Rocky Mountain region that it drains. New developments involved hypotheses that Neogene mantle flow is driving plateau tilting and differential uplift and new and controversial hypotheses for the pre-6 Ma presence and evolution of ancestral rivers that may be important in the history and birth of the present Colorado River. There is a consensus that plateau tilt and uplift models must be tested with multidisciplinary studies involving differential incision studies and additional geochronology and thermochronology to determine the relative importance of tectonic and geomorphic forces that shape the spectacular landscapes of the Colorado Plateau, Arizona and region. In addition to the scientific goals, the meeting participants emphasized the iconic status of Grand Canyon for geosciences and the importance of good communication between the research community, the geoscience education/interpretation community, the public, and the media. Building on a century-long tradition, this region still provides a globally important natural laboratory for studies of the interactions of erosion and tectonism in shaping the landscape of elevated plateaus.

  11. Conservation planning for the Colorado River in Utah

    Science.gov (United States)

    Christine Rasmussen,; Shafroth, Patrick B.

    2016-01-01

    Strategic planning is increasingly recognized as necessary for providing the greatest possible conservation benefits for restoration efforts. Rigorous, science-based resource assessment, combined with acknowledgement of broader basin trends, provides a solid foundation for determining effective projects. It is equally important that methods used to prioritize conservation investments are simple and practical enough that they can be implemented in a timely manner and by a variety of resource managers. With the help of local and regional natural resource professionals, we have developed a broad-scale, spatially-explicit assessment of 146 miles (~20,000 acres) of the Colorado River mainstem in Grand and San Juan Counties, Utah that will function as the basis for a systematic, practical approach to conservation planning and riparian restoration prioritization. For the assessment we have: 1) acquired, modified or created spatial datasets of Colorado River bottomland conditions; 2) synthesized those datasets into habitat suitability models and estimates of natural recovery potential, fire risk and relative cost; 3) investigated and described dominant ecosystem trends and human uses, and; 4) suggested site selection and prioritization approaches. Partner organizations (The Nature Conservancy, National Park Service, Bureau of Land Management and Utah Forestry Fire and State Lands) are using the assessment and datasets to identify and prioritize a suite of restoration actions to increase ecosystem resilience and improve habitat for bottomland species. Primary datasets include maps of bottomland cover types, bottomland extent, maps of areas inundated during high and low flow events, as well as locations of campgrounds, roads, fires, invasive vegetation treatment areas and other features. Assessment of conditions and trends in the project area entailed: 1) assemblage of existing data on geology, changes in stream flow, and predictions of future conditions; 2) identification

  12. Beyond Lees Ferry: Assessing the Long-term Hydrologic Variability of the Lower Colorado River Basin

    Science.gov (United States)

    Wade, L. C.; Rajagopalan, B.; Lukas, J. J.; Kanzer, D.

    2011-12-01

    The future reliability of Colorado River Basin water supplies depends on natural hydrologic variability, climate change impacts and other human factors. Natural variability is the dominant component at annual to decadal time scales and thus, capturing and understanding the full range of such variability is critical to assessing risks to near- and mid-term water supplies. Paleohydrologic reconstructions of annual flow using tree rings provide much longer (400+ years) records of annual flow than do historical gage records, and thus a more complete representation of potential flow sequences. While the long-term natural variability of the Upper Colorado River Basin has been well-captured by high-quality multi-century reconstructions of the annual flow of the Colorado River at Lees Ferry, AZ, there has been no equivalent effort for the whole of the Lower Colorado River Basin, including the Gila River. The contribution of the Lower Basin to overall basin flows is estimated to be 15% on average, but this percentage varies significantly from year to year, potentially impacting water supply risk and management for the entire basin. We present preliminary results from an ongoing effort to assess the hydroclimatic variability of the Lower Basin and to develop reconstructions of annual streamflows for the Gila River and Lower Colorado River near Yuma, AZ, commensurate with the existing Lees Ferry reconstructions. We model the flow of the Gila at the confluence with the Colorado River using Generalized Pareto Distribution (GPD) and a generalized linear model (GLM) using Lower Basin tributaries, including the upper Gila River and its tributaries (e.g., Salt, Tonto, and Verde Rivers). We also present preliminary reconstructions of Lower Basin streamflows from tree-ring data using different modeling approaches, including GLM and non-parametric k-nearest-neighbor (KNN). These reconstructions of the Lower Basin flows should facilitate more robust estimation of water supply risk to

  13. Water power and flood control of Colorado River below Green River, Utah

    Science.gov (United States)

    La Rue, Eugene Clyde; Work, Hubert; Grover, Nathan C.

    1925-01-01

    The purpose of this report is to present the facts regarding available water supply and all known dam sites on Colorado River between Cataract Canyon, Utah, and Parker, Ariz., and to show the relative value of these dam sites. To determine the relative value of the dam sites, a comprehensive plan of development for Colorado River below the mouth of Green River is presented that will provide for the maximum practicable utilization of the potential power, maximum preservation of water for irrigation, effective elimination of the flood menace, and adequate solution of the silt problem. This plan, which is preliminary and is offered by the writer to show the basis for his conclusions relative to flood control, irrigation, power development, and silt storage, contemplates the construction of 13 dams making available 3,383 feet of head for the development of power and a maximum of 42,000,000 acre-feet of storage capacity for the control of floods, equalization of flow, and storage of silt.

  14. Traveltime characteristics of Gore Creek and Black Gore Creek, upper Colorado River basin, Colorado

    Science.gov (United States)

    Gurdak, Jason J.; Spahr, Norman E.; Szmajter, Richard J.

    2002-01-01

    In the Rocky Mountains of Colorado, major highways are often constructed in stream valleys. In the event of a vehicular accident involving hazardous materials, the close proximity of highways to the streams increases the risk of contamination entering the streams. Recent population growth has contributed to increased traffic volume along Colorado highways and has resulted in increased movement of hazardous materials, particularly along Interstate 70. Gore Creek and its major tributary, Black Gore Creek, are vulnerable to such contamination from vehicular accidents along Interstate 70. Gore Creek, major tributary of the Eagle River, drains approximately 102 square miles, some of which has recently undergone significant urban development. The headwaters of Gore Creek originate in the Gore Range in the eastern part of the Gore Creek watershed. Gore Creek flows west to the Eagle River. Beginning at the watershed boundary on Vail Pass, southeast of Vail Ski Resort, Interstate 70 parallels Black Gore Creek and then closely follows Gore Creek the entire length of the watershed. Interstate 70 crosses Gore Creek and tributaries 20 times in the watershed. In the event of a vehicular accident involving a contaminant spill into Gore Creek or Black Gore Creek, a stepwise procedure has been developed for water-resource managers to estimate traveltimes of the leading edge and peak concentration of a conservative contaminant. An example calculating estimated traveltimes for a hypothetical contaminant release in Black Gore Creek is provided. Traveltime measurements were made during May and September along Black Gore Creek and Gore Creek from just downstream from the Black Lakes to the confluence with the Eagle River to account for seasonal variability in stream discharge. Fluorometric dye injection of rhodamine WT and downstream dye detection by fluorometry were used to measure traveltime characteristics of Gore Creek and Black Gore Creek. During the May traveltime measurements

  15. Analysis of drought determinants for the Colorado River Basin

    Energy Technology Data Exchange (ETDEWEB)

    Balling Jr, R.C. [Department of Geography, Arizona State University, Tempe, AZ 85287 (United States); Goodrich, G.B. [Department of Geography and Geology, Western Kentucky University, Bowling Green, KY 42101 (United States)

    2007-05-15

    Ongoing drought in the Colorado River Basin, unprecedented urban growth in the watershed, and numerical model simulations showing higher temperatures and lower precipitation totals in the future have all combined to heighten interest in drought in this region. In this investigation, we use principal components analysis (PCA) to independently assess the influence of various teleconnections on Basin-wide and sub-regional winter season Palmer Hydrological Drought Index (PHDI) and precipitation variations in the Basin. We find that the Pacific Decadal Oscillation (PDO) explains more variance in PHDI than El Nino-Southern Oscillation (ENSO), the Atlantic Multidecadal Oscillation (AMO), and the planetary temperature combined for the Basin as a whole. When rotated PCA is used to separate the Basin into two regions, the lower portion of the Basin is similar to the Basin as a whole while the upper portion, which contains the high-elevation locations important to hydrologic yield for the watershed, demonstrates poorly defined relationships with the teleconnections. The PHDI for the two portions of the Basin are shown to have been out of synch for much of the twentieth century. In general, teleconnection indices account for 19% of the variance in PHDI leaving large uncertainties in drought forecasting.

  16. Debris Flow Occurrence and Sediment Persistence, Upper Colorado River Valley, CO

    Science.gov (United States)

    Grimsley, K. J.; Rathburn, S. L.; Friedman, J. M.; Mangano, J. F.

    2016-07-01

    Debris flow magnitudes and frequencies are compared across the Upper Colorado River valley to assess influences on debris flow occurrence and to evaluate valley geometry effects on sediment persistence. Dendrochronology, field mapping, and aerial photographic analysis are used to evaluate whether a 19th century earthen, water-conveyance ditch has altered the regime of debris flow occurrence in the Colorado River headwaters. Identifying any shifts in disturbance processes or changes in magnitudes and frequencies of occurrence is fundamental to establishing the historical range of variability (HRV) at the site. We found no substantial difference in frequency of debris flows cataloged at eleven sites of deposition between the east (8) and west (11) sides of the Colorado River valley over the last century, but four of the five largest debris flows originated on the west side of the valley in association with the earthen ditch, while the fifth is on a steep hillslope of hydrothermally altered rock on the east side. These results suggest that the ditch has altered the regime of debris flow activity in the Colorado River headwaters as compared to HRV by increasing the frequency of debris flows large enough to reach the Colorado River valley. Valley confinement is a dominant control on response to debris flows, influencing volumes of aggradation and persistence of debris flow deposits. Large, frequent debris flows, exceeding HRV, create persistent effects due to valley geometry and geomorphic setting conducive to sediment storage that are easily delineated by valley confinement ratios which are useful to land managers.

  17. Debris Flow Occurrence and Sediment Persistence, Upper Colorado River Valley, CO.

    Science.gov (United States)

    Grimsley, K J; Rathburn, S L; Friedman, J M; Mangano, J F

    2016-07-01

    Debris flow magnitudes and frequencies are compared across the Upper Colorado River valley to assess influences on debris flow occurrence and to evaluate valley geometry effects on sediment persistence. Dendrochronology, field mapping, and aerial photographic analysis are used to evaluate whether a 19th century earthen, water-conveyance ditch has altered the regime of debris flow occurrence in the Colorado River headwaters. Identifying any shifts in disturbance processes or changes in magnitudes and frequencies of occurrence is fundamental to establishing the historical range of variability (HRV) at the site. We found no substantial difference in frequency of debris flows cataloged at eleven sites of deposition between the east (8) and west (11) sides of the Colorado River valley over the last century, but four of the five largest debris flows originated on the west side of the valley in association with the earthen ditch, while the fifth is on a steep hillslope of hydrothermally altered rock on the east side. These results suggest that the ditch has altered the regime of debris flow activity in the Colorado River headwaters as compared to HRV by increasing the frequency of debris flows large enough to reach the Colorado River valley. Valley confinement is a dominant control on response to debris flows, influencing volumes of aggradation and persistence of debris flow deposits. Large, frequent debris flows, exceeding HRV, create persistent effects due to valley geometry and geomorphic setting conducive to sediment storage that are easily delineated by valley confinement ratios which are useful to land managers.

  18. Debris flow occurrence and sediment persistence, Upper Colorado River Valley, CO

    Science.gov (United States)

    Grimsley, Kyle J; Rathburn, Sara L.; Friedman, Jonathan M.; Mangano, Joseph F.

    2016-01-01

    Debris flow magnitudes and frequencies are compared across the Upper Colorado River valley to assess influences on debris flow occurrence and to evaluate valley geometry effects on sediment persistence. Dendrochronology, field mapping, and aerial photographic analysis are used to evaluate whether a 19th century earthen, water-conveyance ditch has altered the regime of debris flow occurrence in the Colorado River headwaters. Identifying any shifts in disturbance processes or changes in magnitudes and frequencies of occurrence is fundamental to establishing the historical range of variability (HRV) at the site. We found no substantial difference in frequency of debris flows cataloged at eleven sites of deposition between the east (8) and west (11) sides of the Colorado River valley over the last century, but four of the five largest debris flows originated on the west side of the valley in association with the earthen ditch, while the fifth is on a steep hillslope of hydrothermally altered rock on the east side. These results suggest that the ditch has altered the regime of debris flow activity in the Colorado River headwaters as compared to HRV by increasing the frequency of debris flows large enough to reach the Colorado River valley. Valley confinement is a dominant control on response to debris flows, influencing volumes of aggradation and persistence of debris flow deposits. Large, frequent debris flows, exceeding HRV, create persistent effects due to valley geometry and geomorphic setting conducive to sediment storage that are easily delineated by valley confinement ratios which are useful to land managers.

  19. Backwater manipulations for endangered fishes: Management implications of selenium on National Wildlife Refuges of the Lower Colorado River

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Many studies have evaluated selenium in the lower Colorado River, but none have reviewed selenium levels after river water has been directed into previously isolated...

  20. The Niobrara Formation as a challenge to water quality in the Arkansas River, Colorado, USA

    Science.gov (United States)

    Bern, Carleton; Stogner, Sr., Robert W.

    2017-01-01

    Study regionArkansas River, east of the Rocky Mountains.Study focusCretaceous sedimentary rocks in the western United States generally pose challenges to water quality, often through mobilization of salts and trace metals by irrigation. However, in the Arkansas River Basin of Colorado, patchy exposure of multiple Cretaceous formations has made it difficult to identify which formations are most problematic. This paper examines water quality in surface-water inflows along a 26-km reach of the Arkansas River relative to the presence or absence of the Cretaceous Niobrara Formation within the watershed.New hydrological insights for the regionPrincipal component analysis (PCA) shows Niobrara-influenced inflows have distinctive geochemistry, particularly with respect to Na, Mg, SO42−, and Se. Uranium concentrations are also greater in Niobrara-influenced inflows. During the irrigation season, median dissolved solids, Se, and U concentrations in Niobrara-influenced inflows were 83%, 646%, and 55%, respectively, greater than medians where Niobrara Formation surface exposures were absent. During the non-irrigation season, which better reflects geologic influence, the differences were more striking. Median dissolved solids, Se, and U concentrations in Niobrara-influenced inflows were 288%, 863%, and 155%, respectively, greater than median concentrations where the Niobrara Formation was absent. Identification of the Niobrara Formation as a disproportionate source for dissolved solids, Se, and U will allow for more targeted studies and management, particularly where exposures underlie irrigated agriculture.

  1. Sustainable water deliveries from the Colorado River in a changing climate.

    Science.gov (United States)

    Barnett, Tim P; Pierce, David W

    2009-05-05

    The Colorado River supplies water to 27 million users in 7 states and 2 countries and irrigates over 3 million acres of farmland. Global climate models almost unanimously project that human-induced climate change will reduce runoff in this region by 10-30%. This work explores whether currently scheduled future water deliveries from the Colorado River system are sustainable under different climate-change scenarios. If climate change reduces runoff by 10%, scheduled deliveries will be missed approximately 58% of the time by 2050. If runoff reduces 20%, they will be missed approximately 88% of the time. The mean shortfall when full deliveries cannot be met increases from approximately 0.5-0.7 billion cubic meters per year (bcm/yr) in 2025 to approximately 1.2-1.9 bcm/yr by 2050 out of a request of approximately 17.3 bcm/yr. Such values are small enough to be manageable. The chance of a year with deliveries Colorado River flow from the 20th century, which was unusually wet; if the river reverts to its long-term mean, shortfalls increase another 1-1.5 bcm/yr. With either climate-change or long-term mean flows, currently scheduled future water deliveries from the Colorado River are not sustainable. However, the ability of the system to mitigate droughts can be maintained if the various users of the river find a way to reduce average deliveries.

  2. Profile surveys in the Colorado River basin in Wyoming, Utah, Colorado, and New Mexico

    Science.gov (United States)

    Herron, William Harrison

    1917-01-01

    In connection with studies of the utilization of rivers the United States Geological Survey has from time to time made surveys and profiles of some of the more important streams of the country and published the results in its series of water-supply papers. In some parts of the country these surveys were made chiefly to determine the location of power sites on streams adapted to the development of power by low or medium heads of 20 to 100 feet; in others the purpose of the surveys was more closely related to the possibility of storing water at certain points and diverting it for use in irrigation.The earlier surveys, such as those of Green River above Fontenelle, Wyo., made in 1909 (Pls. I-V) were of a reconnaissance type and as a rule show no contours along the banks. The later surveys are typified by that of the Gila in the vicinity of Cliff and Redrock, N. Mex., made in 1915 (Pls. XLI-XLIII) and show conditions in much greater detail. These later surveys were made by means of plane table and stadia. Elevations are based on heights derived from primary or precise levels of the United States Geological Survey. The maps are made in the field and show not only the outlines of river banks, the islands, the positions of rapids, falls, shoals, and existing dams, and the crossings of all ferries and roads, but the contours of banks to an elevation high enough to indicate the possibility of using the stream.

  3. Mean Transit Time as a Predictor of Groundwater Discharge Response in the Upper Colorado River Basin

    Science.gov (United States)

    Solder, J. E.; Heilweil, V. M.; Stolp, B. J.; Susong, D.

    2015-12-01

    The Colorado River and its tributaries support 40 million municipal water users and 5.5 million acres of agriculture in the south western United States (U.S. Bureau of Reclamation, 2012). Recent estimates by Rumsey et al. (2015) suggest that a significant portion (about 50 percent) of surface water flow in the Upper Colorado River Basin (UCRB) is sustained by groundwater discharge to streams. Predicted climate variation (Cook et al., 2015) and increased water demand (U.S. Bureau of Reclamation, 2012) within the UCRB suggest future decreases in groundwater discharge, however transient groundwater responses are not well understood. In this study we calculate groundwater mean transit time (MTT) and transit time distribution (TTD) as predictors of the pattern and timing of groundwater response to hydraulic stress. Samples from nineteen large springs within the UCRB were analyzed for environmental tracers to determine MTT and TTD. The predictive value of the MTT is examined by a statistical analysis of MTT, historical spring discharge records, and the Palmer Hydrological Drought Index. MTTs of the 19 springs range from 10 to 15,000 years with a flow-weighted average of 1,650 years. The composite TTD of the 19 springs suggest that flowpaths representing 45 percent of their combined discharge have transit times greater than 100 years. However, spring discharge records indicate that flow responds to drought on much shorter (0.5 - 6 year) time scales, indicative of a hydraulic pressure response. Springs with shorter MTTs ( 100) also show a hydraulic pressure response. While not fully representative of the UCRB, results from the 19 springs indicate that groundwater discharge responds to climate variation and water-demand imbalances over a relatively short time period of years.

  4. Stratigraphic evidence for the role of lake spillover in the inception of the lower Colorado River in southern Nevada and western Arizona

    Science.gov (United States)

    House, P.K.; Pearthree, P.A.; Perkins, M.E.

    2008-01-01

    Late Miocene and early Pliocene sediments exposed along the lower Colorado River near Laughlin, Nevada, contain evidence that establishment of this reach of the river after 5.6 Ma involved flooding from lake spillover through a bedrock divide between Cottonwood Valley to the north and Mohave Valley to the south. Lacustrine marls interfingered with and conformably overlying a sequence of post-5.6 Ma finegrained valley-fill deposits record an early phase of intermittent lacustrine inundation restricted to Cottonwood Valley. Limestone, mud, sand, and minor gravel of the Bouse Formation were subsequently deposited above an unconformity. At the north end of Mohave Valley, a coarse-grained, lithologically distinct fluvial conglomerate separates subaerial, locally derived fan deposits from subaqueous deposits of the Bouse Formation. We interpret this key unit as evidence for overtopping and catastrophic breaching of the paleodivide immediately before deep lacustrine inundation of both valleys. Exposures in both valleys reveal a substantial erosional unconformity that records drainage of the lake and predates the arrival of sediment of the through-going Colorado River. Subsequent river aggradation culminated in the Pliocene between 4.1 and 3.3 Ma. The stratigraphic associations and timing of this drainage transition are consistent with geochemical evidence linking lacustrine conditions to the early Colorado River, the timings of drainage integration and canyon incision on the Colorado Plateau, the arrival of Colorado River sand at its terminus in the Salton Trough, and a downstream-directed mode of river integration common in areas of crustal extension. ?? 2008 The Geological Society of America.

  5. Flow structures and sandbar dynamics in a canyon river during a controlled flood, Colorado River, Arizona

    Science.gov (United States)

    Wright, S.A.; Kaplinski, M.

    2011-01-01

    In canyon rivers, debris fan constrictions create rapids and downstream pools characterized by secondary flow structures that are closely linked to channel morphology. In this paper we describe detailed measurements of the three-dimensional flow structure and sandbar dynamics of two pools along the Colorado River in the Grand Canyon during a controlled flood release from Glen Canyon Dam. Results indicate that the pools are characterized by large lateral recirculation zones (eddies) resulting from flow separation downstream from the channel constrictions, as well as helical flow structures in the main channel and eddy. The lateral recirculation zones are low-velocity areas conducive to fine sediment deposition, particularly in the vicinity of the separation and reattachment points and are thus the dominant flow structures controlling sandbar dynamics. The helical flow structures also affect morphology but appear secondary in importance to the lateral eddies. During the controlled flood, sandbars in the separation and reattachment zones at both sites tended to build gradually during the rising limb and peak flow. Deposition in shallow water on the sandbars was accompanied by erosion in deeper water along the sandbar slope at the interface with the main channel. Erosion occurred via rapid mass failures as well as by gradual boundary shear stress driven processes. The flow structures and morphologic links at our study sites are similar to those identified in other river environments, in particular sharply curved meanders and channel confluences where the coexistence of lateral recirculation and helical flows has been documented. Copyright 2011 by the American Geophysical Union.

  6. Remote sensing approach to map riparian vegetation of the Colorado River Ecosystem, Grand Canyon area, Arizona

    Science.gov (United States)

    Nguyen, U.; Glenn, E.; Nagler, P. L.; Sankey, J. B.

    2015-12-01

    Riparian zones in the southwestern U.S. are usually a mosaic of vegetation types at varying states of succession in response to past floods or droughts. Human impacts also affect riparian vegetation patterns. Human- induced changes include introduction of exotic species, diversion of water for human use, channelization of the river to protect property, and other land use changes that can lead to deterioration of the riparian ecosystem. This study explored the use of remote sensing to map an iconic stretch of the Colorado River in the Grand Canyon National Park, Arizona. The pre-dam riparian zone in the Grand Canyon was affected by annual floods from spring run-off from the watersheds of Green River, the Colorado River and the San Juan River. A pixel-based vegetation map of the riparian zone in the Grand Canyon, Arizona, was produced from high-resolution aerial imagery. The map was calibrated and validated with ground survey data. A seven-step image processing and classification procedure was developed based on a suite of vegetation indices and classification subroutines available in ENVI Image Processing and Analysis software. The result was a quantitative species level vegetation map that could be more accurate than the qualitative, polygon-based maps presently used on the Lower Colorado River. The dominant woody species in the Grand Canyon are now saltcedar, arrowweed and mesquite, reflecting stress-tolerant forms adapted to alternated flow regimes associated with the river regulation.

  7. Introduction: CRevolution 2: origin and evolution of the Colorado River System II

    Science.gov (United States)

    Karlstrom, Karl E.; Beard, L. Sue; House, Kyle; Young, Richard A.; Aslan, Andres; Billingsley, George; Pederson, Joel

    2012-01-01

    A 2010 Colorado River symposium held in Flagstaff, Arizona, in May 2010, had 70 participants who engaged in intense debate about the origin and evolution of the Colorado River system. This symposium, built on two previous decadal scientific meetings, focused on forging scientific consensus where possible, while also articulating continued controversies regarding the Cenozoic evolution of the Colorado River System and the landscapes of the Colorado Plateau–Rocky Mountain region that it drains. New developments involved hypotheses that Neogene mantle flow is driving plateau tilting and differential uplift, with consensus that multidisciplinary studies involving differential incision studies and additional geochronology and thermochronology are needed to test the relative importance of tectonic and geomorphic forcings in shaping the spectacular landscapes of the Colorado Plateau region. In addition to the scientific goals, the meeting participants emphasized the iconic status of Grand Canyon for geosciences, and the importance of good communication between the research community, the geoscience education/interpretation community, the public, and the media. Building on a century-long tradition, this region still provides a globally important natural laboratory for studies of the interactions of erosion and tectonism in the shaping landscape of elevated plateaus.

  8. Channel mapping river miles 29–62 of the Colorado River in Grand Canyon National Park, Arizona, May 2009

    Science.gov (United States)

    Kaplinski, Matt; Hazel, Joseph E.; Grams, Paul E.; Kohl, Keith; Buscombe, Daniel D.; Tusso, Robert B.

    2017-03-23

    Bathymetric, topographic, and grain-size data were collected in May 2009 along a 33-mi reach of the Colorado River in Grand Canyon National Park, Arizona. The study reach is located from river miles 29 to 62 at the confluence of the Colorado and Little Colorado Rivers. Channel bathymetry was mapped using multibeam and singlebeam echosounders, subaerial topography was mapped using ground-based total-stations, and bed-sediment grain-size data were collected using an underwater digital microscope system. These data were combined to produce digital elevation models, spatially variable estimates of digital elevation model uncertainty, georeferenced grain-size data, and bed-sediment distribution maps. This project is a component of a larger effort to monitor the status and trends of sand storage along the Colorado River in Grand Canyon National Park. This report documents the survey methods and post-processing procedures, digital elevation model production and uncertainty assessment, and procedures for bed-sediment classification, and presents the datasets resulting from this study.

  9. Hydrogeological modeling of water exchange between a river valley aquifer and the Colorado River at a riparian corridor of the Colorado River Delta

    Science.gov (United States)

    Perez-Gonzalez, D.; Ramirez-Hernandez, J.; Zamora, F.

    2008-05-01

    The Colorado River Delta has shown a high capacity of regeneration in spite of the drastic reduction of the freshwater flows. This river has an important ecological value for the remaining ecosystems at the regional and continental level. It is not known when this river will present again surpluses of superficial water in the basin, as it happened in the decades of 1980 and 1990. The ecosystems of the Delta depend on the availability of groundwater to survive. The practices of blanket irrigation in the Valley of Mexicali have favored the vertical refill of the aquifer. Part of this water that infiltrates the ground is captured by the Colorado River (CR). As a consequence, even in years in which the CR has not received surpluses of superficial water low flow can be observed in the river, especially in the area of our study that comprises 12 km of the CR between the interception of the railroad with the river and the entrance to Carranza City. This low flow provides water to maintain the riparian vegetation of the zone. For this reason, it is important to know the hydrologic relationship between the river aquifer and the CR. The purpose of this work is to determine the volumes of water supplied by the aquifer to the riparian system and its relationship with the vegetation. Measurements of the fluctuations of the freatic level (FL) in 27 boreholes located in 8 cross sections during more than 2 years have been used for this study. The system was modelled using the program MODFLOW considering diverse water levels in the CR and flow exchange with the aquifer. The hydrogeological properties of the aquifer were found from slug tests and correlations with the textures of 100 soil samples. The modeling results allow to separate the zone of study in three sections. The first one extends 5km from the railroad to the south. In this section the CR receives water from the aquifer producing the observed water in the river bed all the year. The second section, of approximately 2 km

  10. Importance of the 2014 Colorado River Delta pulse flow for migratory songbirds: Insights from foraging behavior

    Science.gov (United States)

    Darrah, Abigail J.; Greeney, Harold F.; Van Riper, Charles

    2017-01-01

    The Lower Colorado River provides critical riparian areas in an otherwise arid region and is an important stopover site for migrating landbirds. In order to reverse ongoing habitat degradation due to drought and human-altered hydrology, a pulse flow was released from Morelos Dam in spring of 2014, which brought surface flow to dry stretches of the Colorado River in Mexico. To assess the potential effects of habitat modification resulting from the pulse flow, we used foraging behavior of spring migrants from past and current studies to assess the relative importance of different riparian habitats. We observed foraging birds in 2000 and 2014 at five riparian sites along the Lower Colorado River in Mexico to quantify prey attack rates, prey attack maneuvers, vegetation use patterns, and degree of preference for fully leafed-out or flowering plants. Prey attack rate was highest in mesquite (Prosopis spp.) in 2000 and in willow (Salix gooddingii) in 2014; correspondingly, migrants predominantly used mesquite in 2000 and willow in 2014 and showed a preference for willows in flower or fruit in 2014. Wilson’s warbler (Cardellina pusilla) used relatively more low-energy foraging maneuvers in willow than in tamarisk (Tamarix spp.) or mesquite. Those patterns in foraging behavior suggest native riparian vegetation, and especially willow, are important resources for spring migrants along the lower Colorado River. Willow is a relatively short-lived tree dependent on spring floods for dispersal and establishment and thus spring migrants are likely to benefit from controlled pulse flows.

  11. Generalized geologic map of part of the upper Animas River watershed and vicinity, Silverton, Colorado

    Science.gov (United States)

    Yager, D.B.; Bove, D.J.

    2002-01-01

    This dataset represents geology compiled for the upper Animas River Watershed near Silverton, Colorado. The source data used are derived from 1:24,000, 1:20,000, 1:48,000 and 1:250,000-scale geologic maps by geologists who have worked in this area since the early 1960's.

  12. 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...

  13. 75 FR 37749 - White River National Forest, Colorado, Oil and Gas Leasing Environmental Impact Statement

    Science.gov (United States)

    2010-06-30

    ... Forest Service White River National Forest, Colorado, Oil and Gas Leasing Environmental Impact Statement... Oil and Gas Leasing and Final EIS and Record of Decision. The proposed revision includes the following: Changing what lands will be available for oil and gas leasing; changing or adding stipulations to...

  14. The Influence of Dam Discharge Regime and Canyon Orientation on Ecosystem Metabolism in the Colorado River

    Science.gov (United States)

    Kennedy, T. A.; Tietjen, T.; Wright, S.

    2005-05-01

    Since the closure of Glen Canyon Dam and the beginning of flow regulation of the Colorado River in Grand Canyon in 1963, considerable efforts have been directed toward understanding the aquatic ecology of this altered ecosystem. Understanding what controls resource availability has been a central focus of these efforts because the Colorado River supports populations of sport fish and endangered humpback chub, both of which appear to be strongly resource limited. There is evidence that dam discharge regime and canyon orientation influence algal standing crop due to their effects on water velocity (scour) and solar insolation, respectively. We explored whether these physical factors influenced rates of primary production and ecosystem respiration, two different metrics of resource availability, in the clear tailwater section of the Colorado River by conducting whole system metabolism measurements across a range of discharge regimes and in reaches with different orientation (i.e. N-S vs. E-W). We found that while both discharge regime and canyon orientation influence rates of primary production, seasonal changes in light availability appear to have a far stronger influence on rates of primary production in the Colorado River. Water temperature appeared to be the main driver of ecosystem respiration.

  15. 78 FR 59230 - Special Local Regulations; Annual Marine Events on the Colorado River, Between Davis Dam...

    Science.gov (United States)

    2013-09-26

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 100 Special Local Regulations; Annual Marine Events on the Colorado River, Between Davis Dam (Bullhead City, Arizona) and Headgate Dam (Parker, Arizona) Within the San Diego...

  16. 43 CFR 431.7 - Administration and management of the Colorado River Dam Fund.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Administration and management of the..., MAINTENANCE, AND REPLACEMENT AT THE BOULDER CANYON PROJECT, ARIZONA/NEVADA § 431.7 Administration and management of the Colorado River Dam Fund. Reclamation is responsible for the repayment of the Project...

  17. 76 FR 61261 - Safety Zone; IJSBA World Finals; Lower Colorado River, Lake Havasu, AZ

    Science.gov (United States)

    2011-10-04

    ... not be hindered by the safety zone. Recreational vessels will not be allowed to transit through the... vessels intending to transit or anchor in a portion of the lower Colorado River at Lake Havasu from... Captain of the Port will cease enforcement of this safety zone and will announce that fact via...

  18. 78 FR 33703 - Safety Zone; Great Western Tube Float; Colorado River; Parker, AZ

    Science.gov (United States)

    2013-06-05

    ... transit through the safety zone if they request and receive permission from the Captain of the Port or his... or operators of vessels intending to transit or anchor in the impacted portion of the Colorado River... announce that fact via Broadcast Notice to Mariners. (c) Definitions. The following definition applies...

  19. 75 FR 38768 - Ashley National Forest, UT, High Uintas Wilderness-Colorado River Cutthroat Trout Habitat...

    Science.gov (United States)

    2010-07-06

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF AGRICULTURE Forest Service Ashley National Forest, UT, High Uintas Wilderness--Colorado River Cutthroat Trout Habitat Enhancement AGENCY: Forest Service, USDA. ACTION: Notice of intent to prepare an environmental...

  20. Value and Resilience in the Case of 'Invasive' Tamarix in the Colorado River Riparian Corridor

    Science.gov (United States)

    Loring, P. A.; Gerlach, S.; Zamora, F.

    2009-12-01

    A common premise of science for conservation and sustainability is an assumption that despite any human definitions of value, there are ecological first principles, e.g., resilience, which must be understood if sustainability is to be possible. As I show here, however, pursuits such as restoration, conservation, and sustainability remain tangled in (and sometimes at odds with one another regarding) many value-laden decisions regarding the equity, justice, and morality of human-environment interactions. These include such important decisions as: what should be restored or sustained and for whom, how and by whom, and at what cost. This paper uses examples from the lower Colorado River Riparian Corridor, in particular the issue of the so-called ‘invasive’ saltcedar (Tamarix spp.), to illustrate some of the implicit value judgments common to the practice of managing ecosystems. There are many possible perspectives to be taken on a matter like Tamarix, each implicitly or explicitly representing different worldviews and agendas for the ecosystems in question. Resilience theory provides one such perspective, but as I show here, it proves incapable of producing recommendations for managing the corridor that are free of subjective valuations. I end with a case study of habitat and Tamarix management practices in the Mexican portion of the Colorado River Delta, highlighting the proven potential when up-front values are explicitly coupled to the practice of sustainability science, rather than left as details for 'good governance,' a realm presently imagined as separate from science, to sort out. Map of the Colorado River Delta. The Sonoran Institute manages projects in the Mexican portion of the Colorado River Delta region, along the Rio Hardy, the mainstem of the Colorado River in Baja California, MX and in the Cienega de Santa Clara wetlands, Sonora, MX. Map courtesy of Water Education Foundation. www.watereducation.org

  1. The Colorado river delta (Mexico: ecological importance and management = O delta do rio Colorado (Mexico: importância ecológica e gerenciamento

    Directory of Open Access Journals (Sweden)

    José Luis Fermán Almada

    2008-10-01

    Full Text Available The Colorado river delta is a unique coastal system in the world, as it combines two important systems: the Colorado river and the Gulf of California. Consequently, the delta is dominated by bilateral interests, and influenced by administrative, political and natural processes, which involve the countries of the United States and Mexico. Located in the northern part of the Gulf of California, under a condition of natural isolation, a series of environmental attributeshave been developed (biotic and abiotic that are only observed in is region. In this work, the development of the bilateral political relations and the most important ecological characteristicsare presented, as well as the management instruments that have been developed for over 80 years. From these issues, the possible scenario for the region is defined, and the development of methodologies for monitoring the effects of these possible tendencies on the natural components of the delta is proposed.O delta do rio Colorado é uma zona costeira única em todo o mundo, porassociar dois importantes sistemas: o próprio rio Colorado e o Golfo da Califórnia. Conseqüentemente, o delta é dominado por interesses bi-nacionais e influenciado por processos administrativos, políticos e naturais, envolvendo os Estados Unidos e o México. Localizado no norte do Golfo da Califórnia, sob uma condição de isolamento natural,desenvolveu-se uma série de atributos ambientais (bióticos e abióticos que só podem ser vistos nessa região. Neste trabalho, são apresentados o desenvolvimento das relações políticas bilaterais e as características ecológicas mais importantes, bem como osmecanismos de gerenciamento que vêm sido desenvolvidos por mais de 80 anos. A partir dessas questões, é definido um cenário tendencial possível para a região, e o desenvolvimento de metodologias para o acompanhamento dos efeitos dessas possíveis tendências sobre os componentes naturais do delta é proposto.

  2. A large-scale environmental flow experiment for riparian restoration in the Colorado River delta

    Science.gov (United States)

    Shafroth, Patrick B.; Schlatter, Karen; Gomez-Sapiens, Martha; Lundgren, Erick; Grabau, Matthew R.; Ramirez-Hernandez, Jorge; Rodriguez-Burgeueno, J. Eliana; Flessa, Karl W.

    2017-01-01

    Managing streamflow is a widely-advocated approach to provide conditions necessary for seed germination and seedling establishment of trees in the willow family (Salicaceae). Experimental flow releases to the Colorado River delta in 2014 had a primary objective of promoting seedling establishment of Fremont cottonwood (Populus fremontii) and Goodding's willow (Salix gooddingii). We assessed seed germination and seedling establishment of these taxa as well as the non-native tamarisk (Tamarix spp.) and native seepwillow shrubs (Baccharis spp.) in the context of seedling requirements and active land management (land grading, vegetation removal) at 23 study sites along 87 river km. In the absence of associated active land management, experimental flows to the Colorado River delta were minimally successful at promoting establishment of new woody riparian seedlings, except for non-native Tamarix. Our results suggest that the primary factors contributing to low seedling establishment varied across space, but included low or no seed availability in some locations for some taxa, insufficient soil moisture availability during the growing season indicated by deep groundwater tables, and competition from adjacent vegetation (and, conversely, availability of bare ground). Active land management to create bare ground and favorable land grades contributed to significantly higher rates of Salicaceae seedling establishment in a river reach with high groundwater tables. Our results provide insights that can inform future environmental flow deliveries to the Colorado River delta and its ecosystems and other similar efforts to restore Salicaceae taxa around the world.

  3. Alternative Water Allocation in Kyrgyzstan: Lessons from the Lower Colorado River Basin and New South Wales

    Directory of Open Access Journals (Sweden)

    Nazir Mirzaev

    2010-08-01

    Full Text Available Focus group discussions and a modeling approach were applied to determine policy and regulatory refinements for current water allocation practices in Kyrgyzstan. Lessons from the Lower Colorado River basin, Texas and New South Wales, Australia were taken into consideration. The paper analyzes the impact of adopting some of these interventions within the socio-environmental context that currently prevails in Kyrgyzstan. The optimization model for water distribution at the river-basin scale was developed using GAMS 2.25 software. Application of the model to the Akbura River basin indicated efficiencies in the proposed institutional rules especially in low water years.

  4. The importance of base flow in sustaining surface water flow in the Upper Colorado River Basin

    Science.gov (United States)

    Miller, Matthew P.; Buto, Susan G.; Susong, David D.; Rumsey, Christine

    2016-01-01

    The Colorado River has been identified as the most overallocated river in the world. Considering predicted future imbalances between water supply and demand and the growing recognition that base flow (a proxy for groundwater discharge to streams) is critical for sustaining flow in streams and rivers, there is a need to develop methods to better quantify present-day base flow across large regions. We adapted and applied the spatially referenced regression on watershed attributes (SPARROW) water quality model to assess the spatial distribution of base flow, the fraction of streamflow supported by base flow, and estimates of and potential processes contributing to the amount of base flow that is lost during in-stream transport in the Upper Colorado River Basin (UCRB). On average, 56% of the streamflow in the UCRB originated as base flow, and precipitation was identified as the dominant driver of spatial variability in base flow at the scale of the UCRB, with the majority of base flow discharge to streams occurring in upper elevation watersheds. The model estimates an average of 1.8 × 1010 m3/yr of base flow in the UCRB; greater than 80% of which is lost during in-stream transport to the Lower Colorado River Basin via processes including evapotranspiration and water diversion for irrigation. Our results indicate that surface waters in the Colorado River Basin are dependent on base flow, and that management approaches that consider groundwater and surface water as a joint resource will be needed to effectively manage current and future water resources in the Basin.

  5. The twenty-first century Colorado River hot drought and implications for the future

    Science.gov (United States)

    Udall, Bradley; Overpeck, Jonathan

    2017-03-01

    Between 2000 and 2014, annual Colorado River flows averaged 19% below the 1906-1999 average, the worst 15-year drought on record. At least one-sixth to one-half (average at one-third) of this loss is due to unprecedented temperatures (0.9°C above the 1906-1999 average), confirming model-based analysis that continued warming will likely further reduce flows. Whereas it is virtually certain that warming will continue with additional emissions of greenhouse gases to the atmosphere, there has been no observed trend toward greater precipitation in the Colorado Basin, nor are climate models in agreement that there should be a trend. Moreover, there is a significant risk of decadal and multidecadal drought in the coming century, indicating that any increase in mean precipitation will likely be offset during periods of prolonged drought. Recently published estimates of Colorado River flow sensitivity to temperature combined with a large number of recent climate model-based temperature projections indicate that continued business-as-usual warming will drive temperature-induced declines in river flow, conservatively -20% by midcentury and -35% by end-century, with support for losses exceeding -30% at midcentury and -55% at end-century. Precipitation increases may moderate these declines somewhat, but to date no such increases are evident and there is no model agreement on future precipitation changes. These results, combined with the increasing likelihood of prolonged drought in the river basin, suggest that future climate change impacts on the Colorado River flows will be much more serious than currently assumed, especially if substantial reductions in greenhouse gas emissions do not occur.Plain Language SummaryBetween 2000 and 2014, annual Colorado River flows averaged 19% below the 1906-1999 average, the worst 15-year drought on record. Approximately one-third of the flow loss is due to high temperatures now common in the basin, a result of human caused climate change

  6. Modeled streamflow metrics on small, ungaged stream reaches in the Upper Colorado River Basin

    Science.gov (United States)

    Lindsay V. Reynolds,; Shafroth, Patrick B.

    2016-01-20

    Modeling streamflow is an important approach for understanding landscape-scale drivers of flow and estimating flows where there are no streamgage records. In this study conducted by the U.S. Geological Survey in cooperation with Colorado State University, the objectives were to model streamflow metrics on small, ungaged streams in the Upper Colorado River Basin and identify streams that are potentially threatened with becoming intermittent under drier climate conditions. The Upper Colorado River Basin is a region that is critical for water resources and also projected to experience large future climate shifts toward a drying climate. A random forest modeling approach was used to model the relationship between streamflow metrics and environmental variables. Flow metrics were then projected to ungaged reaches in the Upper Colorado River Basin using environmental variables for each stream, represented as raster cells, in the basin. Last, the projected random forest models of minimum flow coefficient of variation and specific mean daily flow were used to highlight streams that had greater than 61.84 percent minimum flow coefficient of variation and less than 0.096 specific mean daily flow and suggested that these streams will be most threatened to shift to intermittent flow regimes under drier climate conditions. Map projection products can help scientists, land managers, and policymakers understand current hydrology in the Upper Colorado River Basin and make informed decisions regarding water resources. With knowledge of which streams are likely to undergo significant drying in the future, managers and scientists can plan for stream-dependent ecosystems and human water users.

  7. Stratigraphy and depositional environments of the upper Pleistocene Chemehuevi Formation along the lower Colorado River

    Science.gov (United States)

    Malmon, Daniel V.; Howard, Keith A.; House, P. Kyle; Lundstrom, Scott C.; Pearthree, Philip A.; Sarna-Wojcicki, Andrei M.; Wan, Elmira; Wahl, David B.

    2011-01-01

    The Chemehuevi Formation forms a conspicuous, widespread, and correlative set of nonmarine sediments lining the valleys of the Colorado River and several of its larger tributaries in the Basin and Range geologic province. These sediments have been examined by geologists since J. S. Newberry visited the region in 1857 and are widely cited in the geologic literature; however their origin remains unresolved and their stratigraphic context has been confused by inconsistent nomenclature and by conflicting interpretations of their origin. This is one of the most prominent stratigraphic units along the river below the Grand Canyon, and the formation records an important event or set of events in the history of the Colorado River. Here we summarize what is known about these deposits throughout their range, present new stratigraphic, sedimentologic, topographic, and tephrochronologic data, and formally define them as a lithostratigraphic unit. The Chemehuevi Formation consists primarily of a bluff-forming mud facies, consisting of gypsum-bearing, horizontally bedded sand, silt, and clay, and a slope-forming sand facies containing poorly bedded, well sorted, quartz rich sand and scattered gravel. The sedimentary characteristics and fossil assemblages of the two facies types suggest that they were deposited in flood plain and channel environments, respectively. In addition to these two primary facies, we identify three other mappable facies in the formation: a thick-bedded rhythmite facies, now drowned by Lake Mead; a valley-margin facies containing abundant locally derived sediment; and several tributary facies consisting of mixed fluvial and lacustrine deposits in the lower parts of major tributary valleys. Observations from the subsurface and at outcrops near the elevation of the modern flood plain suggest that the formation also contains a regional basal gravel member. Surveys of numerous outcrops using high-precision GPS demonstrate that although the sand facies commonly

  8. Land Cover Information for the Upper Colorado River Basin in Daymet Climate Data resolution (nlcd_UCRB_daymet_resolution.txt)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — nlcd_UCRB_daymet_resolution.txt is an Esri ASCII grid representing land cover information for the Upper Colorado River Basin. The 2011 National Land Cover Database...

  9. Hydrologic Soil Group for the Upper Colorado River Basin in Daymet Climate Data resolution (hsg_UCRB_Daymet_resolution.txt)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — hsg_UCRB_Daymet_resolution.txt is an Esri ASCII grid representing the hydrologic soil group (HSG) for the Upper Colorado River Basin. The HSG for an area is...

  10. Available Water Capacity for the Upper Colorado River Basin in Daymet Climate Data resolution (awc_UCRB_Daymet_resolution.txt)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — awc_UCRB_Daymet_resolution.txt is an Esri ASCII grid representing the available water capacity (AWC) for the Upper Colorado River Basin. AWC (available water...

  11. 78 FR 77397 - Flood Control Regulations, Marshall Ford Dam (Mansfield Dam and Lake Travis), Colorado River, Texas

    Science.gov (United States)

    2013-12-23

    ..., school district, or special district with a population of less than 50,000; or (3) a small organization...--city of Hannibal; LCRA--Lower Colorado River Authority; M&T Irr--Modesto & Turlock Irr; Mrcd Irr...

  12. Surficial geologic maps along the riparian zone of the Animas River and its headwater tributaries, Silverton to Durango, Colorado, with upper Animas River watershed gradient profiles

    Science.gov (United States)

    Blair, R.W.; Yager, D.B.; Church, S.E.

    2002-01-01

    This product consists of Adobe Acrobat .PDF format documents for 10 surficial geologic strip maps along the Animas River watershed from its major headwater tributaries, south to Durango, Colorado. The Animas River originates in the San Juan Mountains north of the historic mining town of Silverton, Colorado. The surficial geologic maps identify surficial deposits, such as flood-plain and terrace gravels, alluvial fans, glacial till, talus, colluvium, landslides, and bogs. Sixteen primary units were mapped that included human-related deposits and structures, eight alluvial, four colluvial, one glacial, travertine deposits, and undifferentiated bedrock. Each of the surficial geologic strip maps has .PDF links to surficial geology photographs, which enable the user to take a virtual tour of these deposits. Geochemical data collected from mapped surficial deposits that pre- and postdate mining activity have aided in determining the geochemical baseline in the watershed. Several photographs with their corresponding geochemical baseline profiles are accessible through .PDF links from several of the maps. A single coverage for all surficial deposits mapped is included as an ArcInfo shape file as an Arc Export format .e00 file. A gradient map for major headwater tributary streams to the Animas River is also included. The gradient map has stream segments that are color-coded based on relative variations in slope and .PDF format links to each stream gradient profile. Stream gradients were derived from U.S. Geological Survey 10-m digital elevation model data. This project was accomplished in support of the U.S. Geological Survey's Abandoned Mine Lands Initiative in the San Juan Mountains, Colorado.

  13. Clumped isotope paleothermometry of the Mio-Pliocene freshwater Lake Mohave. Lower ancestral Colorado River, USA

    Science.gov (United States)

    Lang, K. A.; Huntington, K. W.

    2015-12-01

    The fluvio-lacustrine deposits of the Bouse Formation are an archive of ancestral Colorado River integration in the Late Miocene and Early Pliocene. In Mohave Valley along the California-Arizona-Nevada border, exposures of the Bouse Formation are observed ~400 m above the modern river elevation, which has been interpreted as evidence of tectonic uplift following a regionally extensive marine incursion and integration of the ancestral Colorado River by capture. However, recent investigations instead favor a "top-down" process of river integration by sequential infilling of freshwater lakes that does not require subsequent tectonic uplift. Accurate interpretation of the Bouse Formation's depositional environment is needed to test these models and ultimately, constrain the timing and mechanism of southwestern Colorado Plateau uplift. To further constrain interpretations of depositional environment, we present new clumped isotope analyses with major and trace element geochemistry and scanning electron microscopy of carbonate samples from the Bouse Formation in Mohave Valley. Here the Bouse Formation contains three distinct facies: basal marl and limestone overlain by thick beds of calcareous claystone interbedded with siltstone and sandstone and locally overlain by tufa. Bulk geochemistry of all facies is consistent with a similar freshwater source yet each facies is isotopically distinct, potentially indicating a strong influence of facies-specific fractionation processes. Carbonate formation temperatures measured in tufa samples are variable, suggesting multiple generations of calcite precipitation. Formation temperatures from basal marl and claystone samples are generally consistent with near-surface lake temperatures, broadly supporting a lacustrine depositional environment and "top-down" process of ancestral Colorado River integration. More broadly, our results quantify the variability in carbonate formation temperatures with different lacustrine facies and

  14. Sediment delivery by ungaged tributaries of the Colorado River in Grand Canyon, Arizona

    Science.gov (United States)

    Webb, Robert H.; Griffiths, Peter G.; Melis, Theodre S.; Hartley, Daniel R.

    2000-01-01

    Sediment input to the Colorado River in Grand Canyon, Arizona, is a valuable resource required to sustain both terrestrial and aquatic ecosystems. A total of 768 ungaged tributaries deliver sediment to the river between Glen Canyon Dam and the Grand Wash Cliffs (river miles -15 to 276). The 32 tributaries between the dam and Lee's Ferry produce only streamflow floods, whereas 736 tributaries in Grand Canyon produce streamflow floods and debris flows. We used three techniques to estimate annual streamflow sediment yield from ungaged tributaries to the Colorado River. For the Glen Canyon and Marble Canyon reaches (river miles -15 to 61.5), respectively, these techniques indicate that 0.065.106 and 0.610.106 Mg/yr (0.68.106 Mg/yr of total sediment) enters the river. This amount is 20 percent of the sediment yield of the Paria River, the only gaged tributary in this reach and a major sediment contributor to the Colorado River. The amount of sand delivered ranges from 0.10.106 to 0.51.106 Mg/yr, depending on the sand content of streamflow sediment. Sand delivered in Glen Canyon is notably coarser (D50 = 0.24 mm) than sand in other reaches (D50 = 0.15 mm). A relation is given for possible variation of this sediment delivery with climate. Debris flows transport poorly-sorted sediment onto debris fans in the Colorado River. In the pre-dam era, debris fans were completely reworked during Colorado River floods, liberating all fine-grained sediment to the river; in the post-dam river on average only 25 percent of debris-fan volume is reworked, leading to storage of sand in the matrix of debris fans. We develop a sediment-yield model for debris flows that uses a logistic-regression model of debris-flow frequency in Grand Canyon, a regression model of debris-flow volumes, particle- size distributions of intact debris-flow deposits, and debris-fan reworking. On average, debris flows deliver between 0.14.106 and 0.30.106 Mg/yr of sediment to debris fans throughout Grand Canyon

  15. Riparian vegetation dynamics and evapotranspiration in the riparian corridor in the delta of the Colorado River, Mexico.

    Science.gov (United States)

    Nagler, Pamela L; Glenn, Edward P; Hinojosa-Huerta, Osvel; Zamora, Francisco; Howard, Keith

    2008-09-01

    Like other great desert rivers, the Colorado River in the United States and Mexico is highly regulated to provide water for human use. No water is officially allotted to support the natural ecosystems in the delta of the river in Mexico. However, precipitation is inherently variable in this watershed, and from 1981-2004, 15% of the mean annual flow of the Lower Colorado River has entered the riparian corridor below the last diversion point for water in Mexico. These flows include flood releases from US dams and much smaller administrative spills released back to the river from irrigators in the US and Mexico. These flows have germinated new cohorts of native cottonwood and willow trees and have established an active aquatic ecosystem in the riparian corridor in Mexico. We used ground and remote-sensing methods to determine the composition and fractional cover of the vegetation in the riparian corridor, its annual water consumption, and the sources of water that support the ecosystem. The study covered the period 2000-2004, a flood year followed by 4 dry years. The riparian corridor occupies 30,000 ha between flood control levees in Mexico. Annual evapotranspiration (ET), estimated by Moderate Resolution Imaging Spectrometer (MODIS) satellite imagery calibrated against moisture flux tower data, was about 1.1 m yr(-1) and was fairly constant throughout the study period despite a paucity of surface flows 2001-2004. Total ET averaged 3.4 x 10(8)m(3)yr(-1), about 15% of Colorado River water entering Mexico from the US Surface flows could have played only a small part in supporting these high ET losses. We conclude that the riparian ET is supported mainly by the shallow regional aquifer, derived from agricultural return flows, that approaches the surface in the riparian zone. Nevertheless, surface flows are important in germinating cohorts of native trees, in washing salts from the soil and aquifer, and in providing aquatic habitat, thereby enriching the habitat value of

  16. Geospatial database of estimates of groundwater discharge to streams in the Upper Colorado River Basin

    Science.gov (United States)

    Garcia, Adriana; Masbruch, Melissa D.; Susong, David D.

    2014-01-01

    The U.S. Geological Survey, as part of the Department of the Interior’s WaterSMART (Sustain and Manage America’s Resources for Tomorrow) initiative, compiled published estimates of groundwater discharge to streams in the Upper Colorado River Basin as a geospatial database. For the purpose of this report, groundwater discharge to streams is the baseflow portion of streamflow that includes contributions of groundwater from various flow paths. Reported estimates of groundwater discharge were assigned as attributes to stream reaches derived from the high-resolution National Hydrography Dataset. A total of 235 estimates of groundwater discharge to streams were compiled and included in the dataset. Feature class attributes of the geospatial database include groundwater discharge (acre-feet per year), method of estimation, citation abbreviation, defined reach, and 8-digit hydrologic unit code(s). Baseflow index (BFI) estimates of groundwater discharge were calculated using an existing streamflow characteristics dataset and were included as an attribute in the geospatial database. A comparison of the BFI estimates to the compiled estimates of groundwater discharge found that the BFI estimates were greater than the reported groundwater discharge estimates.

  17. Estimates of Water Use of Saltcedar (Tamarix ramosissima) on the Lower Colorado River: from Plant to Stand to River Reach

    Science.gov (United States)

    Glenn, E. P.; Nagler, P. L.; Didan, K.; Osterberg, J.

    2007-12-01

    Saltcedar (Tamarix ramosissima) removal projects have been proposed to salvage water that would other wise support saltcedar evapotranspiration (ET), and to allow native vegetation to recolonize western U.S. riparian corridors. We measured stem-level sap flow at Cibola NWR on the Lower Colorado River to answer some of the scientific questions about the possible consequences of saltcedar removal. We then conducted wide-area studies using remote sensing technology by scaling from the three ground sites using TM- and MODIS-based ET estimates. The sites were different distances from the river channel and differed in depth to water table and salinity of the ground water. Results were then extrapolated to the river reach (from Davis Dam to the delta of the river in Mexico). Saltcedar stands at Cibola had moderate rates of ET, based on remote sensing estimates, averaging 1.1 m yr-1, similar to rates determined for other locations on the river and for other river systems. Leaf area index (LAI) values were also moderate, and stands were relatively open, with areas of bare soil interspersed within stands. Despite high ground water salinity (5,000-10,000 mg l-1), the sites away from the river did not have saline surface soils, supporting studies showing that saltcedar does not salinize riverbanks. Approximately 1 percent of the mean annual river flow is lost to saltcedar ET on the Lower Colorado River in the U.S. Based on these results, the opportunities for water salvage through saltcedar removal appear to be constrained by its modest ET rates.

  18. Drivers of annual to decadal streamflow variability in the lower Colorado River Basin

    Science.gov (United States)

    Lambeth-Beagles, R. S.; Troch, P. A.

    2010-12-01

    The Colorado River is the main water supply to the southwest region. As demand reaches the limit of supply in the southwest it becomes increasingly important to understand the dynamics of streamflow in the Colorado River and in particular the tributaries to the lower Colorado River. Climate change may pose an additional threat to the already-scarce water supply in the southwest. Due to the narrowing margin for error, water managers are keen on extending their ability to predict streamflow volumes on a mid-range to decadal scale. Before a predictive streamflow model can be developed, an understanding of the physical drivers of annual to decadal streamflow variability in the lower Colorado River Basin is needed. This research addresses this need by applying multiple statistical methods to identify trends, patterns and relationships present in streamflow, precipitation and temperature over the past century in four contributing watersheds to the lower Colorado River. The four watersheds selected were the Paria, Little Colorado, Virgin/Muddy, and Bill Williams. Time series data over a common period from 1906-2007 for streamflow, precipitation and temperature were used for the initial analysis. Through statistical analysis the following questions were addressed: 1) are there observable trends and patterns in these variables during the past century and 2) if there are trends or patterns, how are they related to each other? The Mann-Kendall test was used to identify trends in the three variables. Assumptions regarding autocorrelation and persistence in the data were taken into consideration. Kendall’s tau-b test was used to establish association between any found trends in the data. Initial results suggest there are two primary processes occurring. First, statistical analysis reveals significant upward trends in temperatures and downward trends in streamflow. However, there appears to be no trend in precipitation data. These trends in streamflow and temperature speak to

  19. Northern tamarisk beetle (Diorhabda carinulata) and tamarisk (Tamarix spp.) interactions in the Colorado River basin

    Science.gov (United States)

    Nagler, Pamela L.; Nguyen, Uyen; Bateman, Heather L.; Jarchow, Christopher; Glenn, Edward P.; Waugh, William J.; Van Riper, Charles

    2017-01-01

    Northern tamarisk beetles (Diorhabda carinulata) were released in the Upper Colorado River Basin in the United States in 2004–2007 to defoliate introduced tamarisk shrubs (Tamarix spp.) in the region’s riparian zones. The primary purpose was to control the invasive shrub and reduce evapotranspiration (ET) by tamarisk in an attempt to increase stream flows. We evaluated beetle–tamarisk interactions with MODIS and Landsat imagery on 13 river systems, with vegetation indices used as indicators of the extent of defoliation and ET. Beetles are widespread and exhibit a pattern of colonize–defoliate–emigrate, so that riparian zones contain a mosaic of completely defoliated, partially defoliated, and refoliated tamarisk stands. Based on satellite data and ET algorithms, mean ET before beetle release (2000–2006) was 416 mm/year compared to postrelease (2007–2015) ET of 355 mm/year (p<0.05) for a net reduction of 61 mm/year. This is lower than initial literature projections that ET would be reduced by 300–460 mm/year. Reasons for the lower-than-expected ET reductions are because baseline ET rates are lower than initially projected, and percentage ET reduction is low because tamarisk stands tend to regrow new leaves after defoliation and other plants help maintain canopy cover. Overall reductions in tamarisk green foliage during the study are 21%. However, ET in the Upper Basin has shown a steady decline since 2007 and equilibrium has not yet been reached. Defoliation is now proceeding from the Upper Basin into the Lower Basin at a rate of 40 km/year, much faster than initially projected.

  20. Changes in groundwater recharge under projected climate in the upper Colorado River basin

    Science.gov (United States)

    Tillman, Fred D.; Gangopadhyay, Subhrendu; Pruitt, Tom

    2016-07-01

    Understanding groundwater-budget components, particularly groundwater recharge, is important to sustainably manage both groundwater and surface water supplies in the Colorado River basin now and in the future. This study quantifies projected changes in upper Colorado River basin (UCRB) groundwater recharge from recent historical (1950-2015) through future (2016-2099) time periods, using a distributed-parameter groundwater recharge model with downscaled climate data from 97 Coupled Model Intercomparison Project Phase 5 climate projections. Simulated future groundwater recharge in the UCRB is generally expected to be greater than the historical average in most decades. Increases in groundwater recharge in the UCRB are a consequence of projected increases in precipitation, offsetting reductions in recharge that would result from projected increased temperatures.

  1. Changes in groundwater recharge under projected climate in the upper Colorado River basin

    Science.gov (United States)

    Tillman, Fred; Gangopadhyay, Subhrendu; Pruitt, Tom

    2016-01-01

    Understanding groundwater-budget components, particularly groundwater recharge, is important to sustainably manage both groundwater and surface water supplies in the Colorado River basin now and in the future. This study quantifies projected changes in upper Colorado River basin (UCRB) groundwater recharge from recent historical (1950–2015) through future (2016–2099) time periods, using a distributed-parameter groundwater recharge model with downscaled climate data from 97 Coupled Model Intercomparison Project Phase 5 climate projections. Simulated future groundwater recharge in the UCRB is generally expected to be greater than the historical average in most decades. Increases in groundwater recharge in the UCRB are a consequence of projected increases in precipitation, offsetting reductions in recharge that would result from projected increased temperatures.

  2. USGS 2015 JSankey Riparian Vegetation and Colorado River

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data include image-based classifications of total vegetation from 1965, 1973, 1984, 1992, 2002, 2004, 2005, and 2009, and characteristics of the river channel...

  3. Sedimentology and stratigraphy of the Palisades, Lower Comanche, and Arroyo Grande areas of the Colorado River Corridor, Grand Canyon, Arizona

    Science.gov (United States)

    Draut, Amy E.; Rubin, David M.; Dierker, Jennifer L.; Fairley, Helen C.; Griffiths, Ronald E.; Hazel, Joseph E.; Hunter, Ralph E.; Kohl, Keith; Leap, Lisa M.; Nials, Fred L.; Topping, David J.; Yeatts, Michael

    2005-01-01

    This report analyzes various depositional environments in three archaeologically significant areas of the Colorado River corridor in Grand Canyon. Archaeological features are built on and buried by fluvial, aeolian, and locally derived sediment, representing a complex interaction between geologic and cultural history. These analyses provide a basis for determining the potential influence of Glen Canyon Dam operations on selected archaeological sites and thus for guiding dam operations in order to facilitate preservation of cultural resources. This report presents initial results of a joint effort between geologists and archaeologists to evaluate the significance of various depositional processes and environments in the prehistoric formation and modern preservation of archaeological sites along the Colorado River corridor in Grand Canyon National Park. Stratigraphic investigations of the Palisades, Lower Comanche, and Arroyo Grande areas of Grand Canyon yield detailed information regarding the sedimentary history at these locations. Reconstruction of past depositional settings is critical to a thorough understanding of the geomorphic and stratigraphic evolution of these three archaeologically significant areas. This examination of past sedimentary environments allows the relative significance of fluvial, aeolian, debris-fan, and slope-wash sedimentary deposits to be identified at each site. In general the proportion of fluvial sediment (number and thickness of flood deposits) is shown to decrease away from the river, and locally derived sediment becomes more significant. Flood sequences often occur as 'couplets' that contain a fluvial deposit overlain by an interflood unit that reflects reworking of fluvial sediment at the land surface by wind and local runoff. Archaeological features are built on and buried by sediment of various depositional environments, implying a complex interaction between geologic and cultural history. Such field analysis, which combines

  4. Water Demand Management Strategies and Challenges in the Upper Colorado River Basin

    Science.gov (United States)

    Kuhn, R. E.

    2016-12-01

    Under the 1922 Colorado River Compact, the Upper Basin (Colorado, New Mexico, Utah, and Wyoming) has flow obligations at Lee Ferry to downstream states and Mexico. The Colorado River Storage Project Act (CRSPA) of 1956 led to the construction of four large storage reservoirs. These provide river regulation to allow the Upper Basin to meet its obligations. Lake Powell, the largest and most important, and Lake Mead are now operated in a coordinated manner under the 2007 Interim Guidelines. Studies show that at current demand levels and if the hydrologic conditions the Basin has experienced since the mid-1980s continue or get drier, reservoir operations, alone, may not provide the necessary water to meet the Upper Basin's obligations. Therefore, the Upper Basin states are now studying demand management strategies that will reduce consumptive uses when total system reservoir storage reaches critically low levels. Demand management has its own economic, political and technical challenges and limitations and will provide new opportunities for applied research. This presentation will discuss some of those strategies, their challenges, and the kinds of information that research could provide to inform demand management.

  5. Adapting to a Changing Colorado River: Making Future Water Deliveries More Reliable Through Robust Management Strategies

    Science.gov (United States)

    Groves, D.; Bloom, E.; Fischbach, J. R.; Knopman, D.

    2013-12-01

    The U.S. Bureau of Reclamation and water management agencies representing the seven Colorado River Basin States initiated the Colorado River Basin Study in January 2010 to evaluate the resiliency of the Colorado River system over the next 50 years and compare different options for ensuring successful management of the river's resources. RAND was asked to join this Basin Study Team in January 2012 to help develop an analytic approach to identify key vulnerabilities in managing the Colorado River basin over the coming decades and to evaluate different options that could reduce this vulnerability. Using a quantitative approach for planning under uncertainty called Robust Decision Making (RDM), the RAND team assisted the Basin Study by: identifying future vulnerable conditions that could lead to imbalances that could cause the basin to be unable to meet its water delivery objectives; developing a computer-based tool to define 'portfolios' of management options reflecting different strategies for reducing basin imbalances; evaluating these portfolios across thousands of future scenarios to determine how much they could improve basin outcomes; and analyzing the results from the system simulations to identify key tradeoffs among the portfolios. This talk will describe RAND's contribution to the Basin Study, focusing on the methodologies used to to identify vulnerabilities for Upper Basin and Lower Basin water supply reliability and to compare portfolios of options. Several key findings emerged from the study. Future Streamflow and Climate Conditions Are Key: - Vulnerable conditions arise in a majority of scenarios where streamflows are lower than historical averages and where drought conditions persist for eight years or more. - Depending where the shortages occur, problems will arise for delivery obligations for the upper river basin and the lower river basin. The lower river basin is vulnerable to a broader range of plausible future conditions. Additional Investments in

  6. Descriptions of the Animas River-Cement Creek Confluence and Mixing Zone Near Silverton, Colorado, During the Late Summers of 1996-1997

    Science.gov (United States)

    2005-01-01

    Descriptions of the Animas River-Cement Creek Confluence and Mixing Zone near Silverton , Colorado, during the Late Summers of 1996 and 1997 U.S...circum-neutral Animas River in a high-elevation region of the San Juan Mountains near Silverton , Colorado. Cement Creek is acidic and enriched in metals...Animas River drains an extensively mineralized caldera in the San Juan Mountains near Silverton , Colorado (Yager and Bove, 2002). This is an area of

  7. An ecosystem services framework for multidisciplinary research in the Colorado River headwaters

    Science.gov (United States)

    Semmens, D.J.; Briggs, J.S.; Martin, D.A.

    2009-01-01

    A rapidly spreading Mountain Pine Beetle epidemic is killing lodgepole pine forest in the Rocky Mountains, causing landscape change on a massive scale. Approximately 1.5 million acres of lodgepoledominated forest is already dead or dying in Colorado, the infestation is still spreading rapidly, and it is expected that in excess of 90 percent of all lodgepole forest will ultimately be killed. Drought conditions combined with dramatically reduced foliar moisture content due to stress or mortality from Mountain Pine Beetle have combined to elevate the probability of large fires throughout the Colorado River headwaters. Large numbers of homes in the wildland-urban interface, an extensive water supply infrastructure, and a local economy driven largely by recreational tourism make the potential costs associated with such a fire very large. Any assessment of fire risk for strategic planning of pre-fire management actions must consider these and a host of other important socioeconomic benefits derived from the Rocky Mountain Lodgepole Pine Forest ecosystem. This paper presents a plan to focus U.S. Geological Survey (USGS) multidisciplinary fire/beetle-related research in the Colorado River headwaters within a framework that integrates a wide variety of discipline-specific research to assess and value the full range of ecosystem services provided by the Rocky Mountain Lodgepole Pine Forest ecosystem. Baseline, unburned conditions will be compared with a hypothetical, fully burned scenario to (a) identify where services would be most severely impacted, and (b) quantify potential economic losses. Collaboration with the U.S. Forest Service will further yield a distributed model of fire probability that can be used in combination with the ecosystem service valuation to develop comprehensive, distributed maps of fire risk in the Upper Colorado River Basin. These maps will be intended for use by stakeholders as a strategic planning tool for pre-fire management activities and can

  8. Colorado

    Directory of Open Access Journals (Sweden)

    Gerardo Rodríguez Quiroz

    2008-01-01

    Full Text Available La conservación de la biodiversidad cuenta, entre sus principales mecanismos de intervención, con las áreas naturales protegidas. En el alto Golfo de California (AGC se ubica la Reser-va de la Biosfera del Alto Golfo de California y Delta del Río Colorado, en la que subsisten especies de alto valor económico, así como especies en peligro de extinción. Este último factor justificó el establecimiento de la reserva. El estudio analiza la efectividad de la Reserva del Alto Golfo como mecanismo de protección de los recursos naturales, en particular de las que están en riesgo de desaparecer, así como de comprobar si los pescadores han mejorado sus condiciones de vida tras la operación de esa área natural. La exploración se llevó a cabo mediante la aplicación de una encuesta a los pescadores. Se sugiere que es indispensable un gran esfuerzo, de autoridades y grupos organizados, para encontrar soluciones al manejo de la Reserva, a fin fijar un programa que permita la recuperación de las especies en peligro de extinción, elevar la calidad de vida de los pescadores y con ello garantizar un equilibrio entre la conservación y la sustentabilidad de la pesca y de los pescadores en el Alto Golfo de California.

  9. Colorado

    Science.gov (United States)

    2002-01-01

    An early-season snowfall accents the Rocky Mountains through western and central Colorado. This true-color image made from data collected by MODIS on October 26, 2001, highlights the contrast between various irrigated areas and the otherwise dry environment at the foothills of the Rockies. One such example is the city of Denver and its outlying suburbs, which can be seen best in the high-resolution image. In areas that would normally harbor drought-tolerant grasses, shrubs and trees, humans are living, watering their lawns, and farming; those watered, green areas differ substantially from the surrounding hues of brown. Numerous National Parks and Monuments dot the Southwestern U.S. The Great Sand Dunes National Monument is one such park. Running along the western base the Sangre de Cristo Range(just below the image's center), a subsection of the Rockies, the monument possesses some of the highest inland sand dunes in the U.S., with crests reaching over 700 feet.

  10. Streamflow gains and losses in the Colorado River in northwestern Burnet and southeastern San Saba Counties, Texas

    Science.gov (United States)

    Braun, Christopher L.; Grzyb, Scott D.

    2015-08-12

    In October 2012, the U.S. Geological Survey (USGS), in cooperation with the Central Texas Groundwater Conservation District, began an assessment to better understand if and where groundwater from the Ellenburger-San Saba aquifer is discharging to the Colorado River, and if and where Colorado River streamflow is recharging the Ellenburger-San Saba aquifer in the study area. Discharge measurements were made to determine if different reaches of the Colorado River in northwestern Burnet and southeastern San Saba Counties are gaining or losing streamflow, the locations and quantities of gains and losses, and whether the gains and losses can be attributed to interaction between the river and the Ellenbuger-San Saba aquifer. To assess streamflow gains and losses, two sets of synoptic gain-loss discharge measurements representing different streamflow conditions were completed. In the first gain-loss streamflow survey during December 3–6, 2012 (hereinafter the fall 2012 gain-loss survey), discharge measurements were made at low-flow conditions ranging from about 30 to 60 cubic feet per second (ft3/s) at seven locations along the Colorado River. In the second gain-loss streamflow survey during May 31–June 1, 2014 (hereinafter the spring 2014 gain-loss survey), discharge measurements were made at high-flow conditions ranging from about 660 to 900 ft3/s at 12 locations along the Colorado River.

  11. Regional variability in dust-on-snow processes and impacts in the Upper Colorado River Basin

    Science.gov (United States)

    Skiles, S. McKenzie; Painter, Thomas H.; Belnap, Jayne; Holland, Lacey; Reynolds, Richard; Goldstein, Harland; Lin, J.

    2015-01-01

    Dust deposition onto mountain snow cover in the Upper Colorado River Basin frequently occurs in the spring when wind speeds and dust emission peaks on the nearby Colorado Plateau. Dust loading has increased since the intensive settlement in the western USA in the mid 1880s. The effects of dust-on-snow have been well studied at Senator Beck Basin Study Area (SBBSA) in the San Juan Mountains, CO, the first high-altitude area of contact for predominantly southwesterly winds transporting dust from the southern Colorado Plateau. To capture variability in dust transport from the broader Colorado Plateau and dust deposition across a larger area of the Colorado River water sources, an additional study plot was established in 2009 on Grand Mesa, 150 km to the north of SBBSA in west central, CO. Here, we compare the 4-year (2010–2013) dust source, deposition, and radiative forcing records at Grand Mesa Study Plot (GMSP) and Swamp Angel Study Plot (SASP), SBBSA's subalpine study plot. The study plots have similar site elevations/environments and differ mainly in the amount of dust deposited and ensuing impacts. At SASP, end of year dust concentrations ranged from 0.83 mg g−1 to 4.80 mg g−1, and daily mean spring dust radiative forcing ranged from 50–65 W m−2, advancing melt by 24–49 days. At GMSP, which received 1.0 mg g−1 less dust per season on average, spring radiative forcings of 32–50 W m−2 advanced melt by 15–30 days. Remote sensing imagery showed that observed dust events were frequently associated with dust emission from the southern Colorado Plateau. Dust from these sources generally passed south of GMSP, and back trajectory footprints modelled for observed dust events were commonly more westerly and northerly for GMSP relative to SASP. These factors suggest that although the southern Colorado Plateau contains important dust sources, dust contributions from other dust sources contribute to dust loading in this region

  12. A Groundwater flow Model of the Colorado River Delta to Support Riparian Habitat Restoration in Northern Mexico

    Science.gov (United States)

    Maddock, T.; Feirstein, E.; Baird, K. J.; Ajami, H.

    2007-05-01

    Quantification of groundwater flow dynamics and of the interactions among groundwater, surface water, and riparian vegetation, represent key components in the development of a balanced restoration plan for functional riparian ecosystems. A groundwater model was developed using MODFLOW 2000 to support of riparian restoration along the Colorado River Delta (Mexico: Baja California, Sonora). The Colorado River is widely recognized as one of the most modified and allocated rivers in the United States. For over 50 years flows into the Delta were severely reduced by the requirements of an emergent American West. However, subsequent to discharge pulses associated with the filling of Lake Powell, and the increased precipitation that accompanied ENSO cycles, a semblance of a native riparian habitat has been observed in the Delta since the 1980's (Zamora- Arroyo et al. 2001). The Delta and the riparian ecosystems of the region have since become the focus of a substantial body of multidisciplinary research. The research goal is to understand water table dynamics with particular attention to stream-aquifer interactions and groundwater behavior in the root zone. Groundwater reliant transpiration requirements were quantified for a set of dominant native riparian species using the Riparian ET (RIP-ET) package, an improved MODFLOW evapotranspiration (ET) module. RIP-ET simulates ET using a set of eco-physiologically based curves that more accurately represents individual plant species, reflects habitat complexity, and deals spatially with plant and water table distribution. When used in conjunction with a GIS based postprocessor (RIP-GIS.net), RIP-ET provides the basis for mapping groundwater conditions as they relate to user-specified plant groups. This explicit link between groundwater and plant sustainability is a driver to restoration design and allows for scenario modeling of various hydrologic conditions. Groundwater requirements determined in this research will be used by

  13. Chronology of Miocene Pliocene deposits at Split Mountain Gorge, Southern California: A record of regional tectonics and Colorado River evolution

    Science.gov (United States)

    Dorsey, Rebecca J.; Fluette, Amy; McDougall, Kristin; Housen, Bernard A.; Janecke, Susanne U.; Axen, Gary J.; Shirvell, Catherine R.

    2007-01-01

    Late Miocene to early Pliocene deposits at Split Mountain Gorge, California, preserve a record of basinal response to changes in regional tectonics, paleogeography, and evolution of the Colorado River. The base of the Elephant Trees Formation, magnetostratigraphically dated as 8.1 ± 0.4 Ma, provides the earliest well-dated record of extension in the southwestern Salton Trough. The oldest marine sediments are ca. 6.3 Ma. The nearly synchronous timing of marine incursion in the Salton Trough and northern Gulf of California region supports a model for localization of Pacific North America plate motion in the Gulf ca. 6 Ma. The first appearance of Colorado River sand at the Miocene-Pliocene boundary (5.33 Ma) suggests rapid propagation of the river to the Salton Trough, and supports a lake-spillover hypothesis for initiation of the lower Colorado River.

  14. Annual suspended-sediment loads in the Colorado River near Cisco, Utah, 1930-82

    Science.gov (United States)

    Thompson, K.R.

    1985-01-01

    The Colorado River upstream of gaging station 09180500 near Cisco, Utah, drains about 24,100 square miles in Utah and Colorado. Altitudes in the basin range from 12,480 feet near the headwaters to 4,090 feet at station 09180500. The average annual precipitation for 1894-1982 near the station was 7.94 inches. The average annual precipitation near the headwaters often exceeds 50 inches. Rocks ranging in age from Precambrian to Holocene are exposed in the drainage basin upstream from station 09180500. Shale, limestone, siltstone, mudstone, and sandstone probably are the most easily eroded rocks in the basin, and they contribute large quantities of sediment to the Colorado River. During 1930-82, the U.S. Geological Survey collected records of fluvial sediment at station 09180500. Based on these records, the mean annual suspended-sediment load was 11,390,000 tone, ranging from 2,038,000 tons in water year 1981 to 35,700,000 tons in water year 1938. The minimum daily load of 14 tons was on August 22, 1960, and the maximum daily load of 2,790,000 tons was on October 14, 1941. (USGS)

  15. Survival, growth, and movement of subadult humpback chub, Gila cypha, in the Little Colorado River, Arizona

    Science.gov (United States)

    Dzul, Maria C.; Yackulic, Charles B.; Stone, Dennis M.; Van Haverbeke, David R.

    2016-01-01

    Ecologists estimate vital rates, such as growth and survival, to better understand population dynamics and identify sensitive life history parameters for species or populations of concern. Here, we assess spatiotemporal variation in growth, movement, density, and survival of subadult humpback chub living in the Little Colorado River, Grand Canyon, AZ from 2001–2002 and 2009–2013. We divided the Little Colorado River into three reaches and used a multistate mark-recapture model to determine rates of movement and differences in survival and density between sites for different cohorts. Additionally, site-specific and year-specific effects on growth were evaluated using a linear model. Results indicate that summer growth was higher for upstream sites compared with downstream sites. In contrast, there was not a consistent spatial pattern across years in winter growth; however, river-wide winter growth was negatively related to the duration of floods from 1 October to 15 May. Apparent survival was estimated to be lower at the most downstream site compared with the upstream sites; however, this could be because in part of increased emigration into the Colorado River at downstream sites. Furthermore, the 2010 cohort (i.e. fish that are age 1 in 2010) exhibited high apparent survival relative to other years. Movement between reaches varied with year, and some years exhibited preferential upstream displacement. Improving understanding of spatiotemporal effects on age 1 humpback chub survival can help inform current management efforts to translocate humpback chub into new locations and give us a better understanding of the factors that may limit this tributary's carrying capacity for humpback chub.

  16. Oil and Gas Well locations, Upper Colorado River Basin, 2007

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Federal onshore lands contain an estimated 20 percent of the oil and 25 percent of the undiscovered natural gas resources in the United States (U.S. Bureau of Land...

  17. Study of extrabasinal-sourced rock clasts in Mesozoic and Cenozoic conglomerates and stream terrace gravels from the Colorado River Basin upstream from the Grand Canyon

    Science.gov (United States)

    Stoffer, P. W.; Dearaujo, J.; Li, A.; Adam, H.; White, L.

    2008-12-01

    Far-travelled durable, extrabasinal pebbles occur in Mesozoic and Tertiary conglomerate-bearing rock formations and in unconsolidated stream terrace gravels and mesa-capping gravel deposits of Late Tertiary and Quaternary age throughout the Colorado Plateau. Pebble collections were made from each of the major modern tributaries of the Colorado River for possible correlation of remnant gravel deposits remaining from the ancestral regional drainage system that existed prior to the formation of the Grand Canyon. Pebble collecting and sorting techniques were used to make representative collections with both representative and eye-catching lithologies that can be most useful for correlation. Pebbles found in the conglomerate and younger gravel deposits were evaluated to determine general sediment source areas based on unique lithologies, pebble-shape characteristics, and fossils. Chert pebbles derived from source areas in the Great Basin region during the Mesozoic are perhaps the most common, and many of these display evidence of tectonic fracturing during deep burial sometime during their geologic journey. Unique chert pebble lithologies correlate to specific rock units including chert-bearing horizons within the Triassic Shinarump Formation, the Jurassic Morrison and Navajo Formations, and the Cretaceous Mancos Shale. Quartzite, metaconglomerate, and granitic rocks derived from Precambrian rocks of the Rocky Mountain region are also common. Reworked rounded and flattened quartzite cobbles probably derived from shingled beaches along the western shoreline of the Late Cretaceous Western Interior Seaway are also common along the Green River drainage. Xenolith-bearing volcanic rocks, fossil wood, and shell fossils preserved in concretion matrix can be linked to other unique source areas and stratigraphic units across the region. By correlating the pebbles with their sources we gain insight into the erosional history of the Colorado Plateau and the evolution of the

  18. Comparison of two methods for estimating base flow in selected reaches of the South Platte River, Colorado

    Science.gov (United States)

    Capesius, Joseph P.; Arnold, L. Rick

    2012-01-01

    The U.S. Geological Survey, in cooperation with the Colorado Water Conservation Board, compared two methods for estimating base flow in three reaches of the South Platte River between Denver and Kersey, Colorado. The two methods compared in this study are the Mass Balance and the Pilot Point methods. Base-flow estimates made with the two methods were based upon a 54-year period of record (1950 to 2003).

  19. Differences in macroinvertebrate community structure in streams and rivers with different hydrologic regimes in the semi-arid Colorado Plateau

    Science.gov (United States)

    Miller, Matthew P.; Brasher, Anne M.D.

    2011-01-01

    Aquatic macroinvertebrates are sensitive to changes in their chemical and physical environment, and as such, serve as excellent indicators of overall ecosystem health. Moreover, temporal and spatial differences in macroinvertebrate community structure can be used to investigate broad issues in aquatic science, such as the hypothesis that changes in climate are likely to have disproportionately large effects on small, intermittent stream ecosystems. We quantified macroinvertebrate community structure and abiotic conditions at ten stream sites with different dominant hydrologic regimes in the Colorado Plateau, ranging from small, intermittent desert streams to large perennial mountain rivers. Considerable differences were observed in community structure between sites with differing hydrologic regimes. Quantitative results of non-metric multidimensional scaling (NMDS) ordination and Spearman rank correlations between physical habitat and macroinvertebrate resemblance matrices indicate that discharge, geomorphic channel unit type (% pools vs. % riffles), percent of substrate composed of sand, and velocity were the subset of measured habitat variables that best explained the differences in macroinvertebrate community structure among sites. Of the 134 taxa identified, nine taxa explained 95 % of the variability in community structure between sites. These results add to a growing base of knowledge regarding the functioning of lotic ecosystems in the Colorado Plateau, and provide timely information on anticipated changes in the structure and function of aquatic ecosystems in response to predicted future environmental conditions.

  20. 2007 Weather and Aeolian Sand-Transport Data from the Colorado River Corridor, Grand Canyon, Arizona

    Science.gov (United States)

    Draut, Amy E.; Andrews, Timothy; Fairley, Helen C.; Brown, Christopher R.

    2009-01-01

    Weather data constitute an integral part of ecosystem monitoring in the Colorado River corridor and are particularly valuable for understanding processes of landscape change that contribute to the stability of archeological sites. Data collected in 2007 are reported from nine weather stations in the Colorado River corridor through Grand Canyon, Ariz. The stations were deployed in February and March 2007 to measure wind speed and direction, rainfall, air temperature, relative humidity, and barometric pressure. Sand traps near each weather station collect windblown sand, from which daily aeolian sand-transport rates are calculated. The data reported here were collected as part of an ongoing study to test and evaluate methods for quantifying processes that affect the physical integrity of archeological sites along the river corridor; as such, these data can be used to identify rainfall events capable of causing gully incision and to predict likely transport pathways for aeolian sand, two landscape processes integral to the preservation of archeological sites. Weather data also have widespread applications to other studies of physical, cultural, and biological resources in Grand Canyon. Aeolian sand-transport data reported here, collected in the year before the March 2008 High-Flow Experiment (HFE) at Glen Canyon Dam, represent baseline data against which the effects of the 2008 HFE on windblown sand will be compared in future reports.

  1. Mercury and selenium accumulation in the Colorado River food web, Grand Canyon, USA

    Science.gov (United States)

    Walters, David M.; E.J. Rosi-Marshall,; Kennedy, Theodore A.; W.F. Cross,; C.V. Baxter,

    2015-01-01

    Mercury (Hg) and selenium (Se) biomagnify in aquatic food webs and are toxic to fish and wildlife. The authors measured Hg and Se in organic matter, invertebrates, and fishes in the Colorado River food web at sites spanning 387 river km downstream of Glen Canyon Dam (AZ, USA). Concentrations were relatively high among sites compared with other large rivers (mean wet wt for 6 fishes was 0.17–1.59 μg g–1 Hg and 1.35–2.65 μg g–1 Se), but consistent longitudinal patterns in Hg or Se concentrations relative to the dam were lacking. Mercury increased (slope = 0.147) with δ15N, a metric of trophic position, indicating biomagnification similar to that observed in other freshwater systems. Organisms regularly exceeded exposure risk thresholds for wildlife and humans (6–100% and 56–100% of samples for Hg and Se, respectfully, among risk thresholds). In the Colorado River, Grand Canyon, Hg and Se concentrations pose exposure risks for fish, wildlife, and humans, and the findings of the present study add to a growing body of evidence showing that remote ecosystems are vulnerable to long-range transport and subsequent bioaccumulation of contaminants. Management of exposure risks in Grand Canyon will remain a challenge, as sources and transport mechanisms of Hg and Se extend far beyond park boundaries. Environ Toxicol Chem2015;9999:1–10

  2. Effects of a test flood on fishes of the Colorado River in Grand Canyon, Arizona

    Science.gov (United States)

    Valdez, R.A.; Hoffnagle, T.L.; McIvor, C.C.; McKinney, T.; Leibfried, W.C.

    2001-01-01

    A beach/habitat-building flow (i.e., test flood) of 1274 m3/s, released from Glen Canyon Dam down the Colorado River through Grand Canyon, had little effect on distribution, abundance, or movement of native fishes, and only short-term effects on densities of some nonnative species Shoreline and backwater catch rates of native fishes, including juvenile humpback chub (Gila cypha), flannelmouth suckers (Catostomus latipinnis), and bluehead suckers (C. discobolus), and all ages of speckled dace (Rhinichthys osculus), were not significantly different before and after the flood. Annual spring spawning migrations of flannelmouth suckers into the Paria River and endangered humpback chub into the Little Colorado River (LCR) took place during and after the flood, indicating no impediment to fish migrations. Pre-spawning adults staged in large slack water pools formed at the mouths of these tributaries during the flood. Net movement and habitat used by nine radio-tagged adult humpback chub during the flood were not significantly different from prior observations. Diet composition of adult humpback chub varied, but total biomass did not differ significantly before, during, and after the flood, indicating opportunistic feeding for a larger array of available food items displaced by the flood. Numbers of nonnative rainbow trout (Oncorhynchus mykiss) disadvantage alien predators and competitors and enhance survival of native fishes.

  3. Erosion properties of cohesive sediments in the Colorado River in Grand Canyon

    Science.gov (United States)

    Akahori, R.; Schmeeckle, M.W.; Topping, D.J.; Melis, T.S.

    2008-01-01

    Cohesive sediment deposits characterized by a high fraction of mud (silt plus clay) significantly affect the morphology and ecosystem of rivers. Potentially cohesive sediment samples were collected from deposits in the Colorado River in Marble and Grand Canyons. The erosion velocities of these samples were measured in a laboratory flume under varying boundary shear stresses. The non-dimensional boundary shear stress at which erosion commenced showed a systematic deviation from that of non-cohesive sediments at mud fractions greater than 0.2. An empirical relation for the boundary shear stress threshold of erosion as a function of mud fraction was proposed. The mass erosion rate was modelled using the Ariathurai-Partheniades equation. The erosion rate parameter of this equation was found to be a strong function of mud fraction. Under similar boundary shear stress and sediment supply conditions in the Colorado River, cohesive lateral eddy deposits formed of mud fractions in excess of 0.2 will erode less rapidly than non-cohesive deposits. Copyright ?? 2008 John Wiley & Sons, Ltd.

  4. Mercury and selenium accumulation in the Colorado River food web, Grand Canyon, USA.

    Science.gov (United States)

    Walters, David M; Rosi-Marshall, Emma; Kennedy, Theodore A; Cross, Wyatt F; Baxter, Colden V

    2015-10-01

    Mercury (Hg) and selenium (Se) biomagnify in aquatic food webs and are toxic to fish and wildlife. The authors measured Hg and Se in organic matter, invertebrates, and fishes in the Colorado River food web at sites spanning 387 river km downstream of Glen Canyon Dam (AZ, USA). Concentrations were relatively high among sites compared with other large rivers (mean wet wt for 6 fishes was 0.17-1.59 μg g(-1) Hg and 1.35-2.65 μg g(-1) Se), but consistent longitudinal patterns in Hg or Se concentrations relative to the dam were lacking. Mercury increased (slope = 0.147) with δ(15) N, a metric of trophic position, indicating biomagnification similar to that observed in other freshwater systems. Organisms regularly exceeded exposure risk thresholds for wildlife and humans (6-100% and 56-100% of samples for Hg and Se, respectfully, among risk thresholds). In the Colorado River, Grand Canyon, Hg and Se concentrations pose exposure risks for fish, wildlife, and humans, and the findings of the present study add to a growing body of evidence showing that remote ecosystems are vulnerable to long-range transport and subsequent bioaccumulation of contaminants. Management of exposure risks in Grand Canyon will remain a challenge, as sources and transport mechanisms of Hg and Se extend far beyond park boundaries.

  5. The 2014 water release into the arid Colorado River delta and associated water losses by evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Daesslé, L.W., E-mail: walter@uabc.edu.mx [Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, CarreteraTranspeninsular Tijuana-Ensenada No. 3917, Fraccionamiento Playitas, CP 22860 Ensenada, Baja California (Mexico); Friedrich-Alexander University of Erlangen-Nuremberg (FAU), Department of Geography and Geosciences, GeoZentrum Nordbayern, Schlossgarten 5, 91054 Erlangen (Germany); Geldern, R. van [Friedrich-Alexander University of Erlangen-Nuremberg (FAU), Department of Geography and Geosciences, GeoZentrum Nordbayern, Schlossgarten 5, 91054 Erlangen (Germany); Orozco-Durán, A. [Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, CarreteraTranspeninsular Tijuana-Ensenada No. 3917, Fraccionamiento Playitas, CP 22860 Ensenada, Baja California (Mexico); Barth, J.A.C. [Friedrich-Alexander University of Erlangen-Nuremberg (FAU), Department of Geography and Geosciences, GeoZentrum Nordbayern, Schlossgarten 5, 91054 Erlangen (Germany)

    2016-01-15

    For the first time in history, water was intentionally released for environmental purposes into the final, otherwise dry, 160-km stretch of the Colorado River basin, south of the Mexican border. Between March and May 2014 three pulses of water with a total volume of 132 × 10{sup 6} m{sup 3} were released to assess the restoration potential of endemic flora along its course and to reach its estuary. The latter had not received a sustained input of fresh water and nutrients from its main fluvial source for over 50 years because of numerous upstream dam constructions. During this pulse flow large amounts of water were lost and negligible amounts reached the ocean. While some of these water losses can be attributed to plant uptake and infiltration, we were able to quantify evaporation losses between 16.1 to 17.3% of the original water mass % within the first 80 km after the Morels Dam with water stable isotope data. Our results showed no evidence for freshwater reaching the upper Colorado River estuary and it is assumed that the pulse flow had only negligible influences on the coastal ecosystem. Future water releases that aim on ecological restoration need to become more frequent and should have larger volumes if more significant effects are to be established on the area. - Highlights: • Isotope ratios of oxygen and hydrogen quantify water lost through evaporation. • Evaporation losses between 16.1 and 17.3% during the 2014 Colorado River • Larger water volumes are required to influence the estuary ecosystem.

  6. Seasonal hyporheic dynamics control coupled microbiology and geochemistry in Colorado River sediments

    Science.gov (United States)

    Danczak, Robert E.; Sawyer, Audrey H.; Williams, Kenneth H.; Stegen, James C.; Hobson, Chad; Wilkins, Michael J.

    2016-12-01

    Riverbed microbial communities play an oversized role in many watershed ecosystem functions, including the processing of organic carbon, cycling of nitrogen, and alterations to metal mobility. The structure and activity of microbial assemblages depend in part on geochemical conditions set by river-groundwater exchange or hyporheic exchange. To assess how seasonal changes in river-groundwater mixing affect these populations in a snowmelt-dominated fluvial system, vertical sediment and pore water profiles were sampled at three time points at one location in the hyporheic zone of the Colorado River and analyzed by using geochemical measurements, 16S rRNA gene sequencing, and ecological modeling. Oxic river water penetrated deepest into the subsurface during peak river discharge, while under base flow conditions, anoxic groundwater dominated shallower depths. Over a 70 cm thick interval, riverbed sediments were therefore exposed to seasonally fluctuating redox conditions and hosted microbial populations statistically different from those at both shallower and deeper locations. Additionally, microbial populations within this zone were shown to be the most dynamic across sampling time points, underlining the critical role that hyporheic mixing plays in constraining microbial abundances. Given such mixing effects, we anticipate that future changes in river discharge in mountainous, semiarid western U.S. watersheds may affect microbial community structure and function in riverbed environments, with potential implications for biogeochemical processes in riparian regions.

  7. Proceedings of the Colorado River Basin Science and Resource Management Symposium, November 18-20, 2008, Scottsdale, Arizona

    Science.gov (United States)

    Melis, Theodore S.; Hamill, John F.; Bennett, Glenn E.; Coggins,, Lewis G.; Grams, Paul E.; Kennedy, Theodore A.; Kubly, Dennis M.; Ralston, Barbara E.

    2010-01-01

    Since the 1980s, four major science and restoration programs have been developed for the Colorado River Basin to address primarily the conservation of native fish and other wildlife pursuant to the Endangered Species Act (ESA): (1) Recovery Implementation Program for Endangered Fish Species in the Upper Colorado River Basin (commonly called the Upper Colorado River Endangered Fish Recovery Program) (1988); (2) San Juan River Basin Recovery Implementation Program (1992); (3) Glen Canyon Dam Adaptive Management Program (1997); and (4) Lower Colorado River Multi-Species Conservation Program (2005). Today, these four programs, the efforts of which span the length of the Colorado River, have an increasingly important influence on water management and resource conservation in the basin. The four efforts involve scores of State, Federal, and local agencies; Native American Tribes; and diverse stakeholder representatives. The programs have many commonalities, including similar and overlapping goals and objectives; comparable resources and threats to those resources; and common monitoring, research, and restoration strategies. In spite of their commonalities, until recently there had been no formal opportunity for information exchange among the programs. To address this situation, the U.S. Geological Survey (USGS) worked in coordination with the four programs and numerous Federal and State agencies to organize the first Colorado River Basin Science and Resource Management Symposium, which took place in Scottsdale, AZ, in November 2008. The symposium's primary purpose was to promote an exchange of information on research and management activities related to the restoration and conservation of the Colorado River and its major tributaries. A total of 283 managers, scientists, and stakeholders attended the 3-day symposium, which included 87 presentations and 27 posters. The symposium featured plenary talks by experts on a variety of topics, including overviews of the four

  8. Nearshore temperature findings for the Colorado River in Grand Canyon, Arizona: possible implications for native fish

    Science.gov (United States)

    Ross, Robert P.; Vernieu, William S.

    2013-01-01

    Since the completion of Glen Canyon Dam, Arizona, in 1963, downstream water temperatures in the main channel of the Colorado River in Glen, Marble, and Grand Canyons are much colder in summer. This has negatively affected humpback chub (Gila cypha) and other native fish adapted to seasonally warm water, reducing main-channel spawning activity and impeding the growth and development of larval and juvenile fish. Recently published studies by U.S. Geological Survey scientists found that under certain conditions some isolated nearshore environments in Grand Canyon allow water to become separated from the main-channel current and to warm, providing refuge areas for the development of larval and juvenile fish.

  9. Southwestern riparian plant trait matrix, Colorado River, Grand Canyon, 2014 to 2016 - Data

    Science.gov (United States)

    Palmquist, Emily C.; Ralston, Barbara; Sarr, Daniel; Merritt, David M.; Shafroth, Patrick B.; Scott, J. A.

    2016-01-01

    This dataset contains information on the physical traits and environmental tolerances of plant species occurring along the lower Colorado River through Grand Canyon. Due to the unique combination of plant species within the Grand Canyon, this flora shares species with many riparian areas in the western U.S.A. and represents obligate wetland to obligate upland plant species. Data for the matrix were compiled from published scientific papers, unpublished reports, plant fact sheets, existing trait databases, regional floras, and plant guides. Categorical, ordinal, and continuous data are included in this dataset. This dataset does not contain sensitive or classified data.

  10. Ranking contributing areas of salt and selenium in the Lower Gunnison River Basin, Colorado, using multiple linear regression models

    Science.gov (United States)

    Linard, Joshua I.

    2013-01-01

    Mitigating the effects of salt and selenium on water quality in the Grand Valley and lower Gunnison River Basin in western Colorado is a major concern for land managers. Previous modeling indicated means to improve the models by including more detailed geospatial data and a more rigorous method for developing the models. After evaluating all possible combinations of geospatial variables, four multiple linear regression models resulted that could estimate irrigation-season salt yield, nonirrigation-season salt yield, irrigation-season selenium yield, and nonirrigation-season selenium yield. The adjusted r-squared and the residual standard error (in units of log-transformed yield) of the models were, respectively, 0.87 and 2.03 for the irrigation-season salt model, 0.90 and 1.25 for the nonirrigation-season salt model, 0.85 and 2.94 for the irrigation-season selenium model, and 0.93 and 1.75 for the nonirrigation-season selenium model. The four models were used to estimate yields and loads from contributing areas corresponding to 12-digit hydrologic unit codes in the lower Gunnison River Basin study area. Each of the 175 contributing areas was ranked according to its estimated mean seasonal yield of salt and selenium.

  11. Salinity of the Little Colorado River in Grand Canyon confers anti-parasitic properties on a native fish

    Science.gov (United States)

    Ward, David L.

    2012-01-01

    Water in the Little Colorado River within Grand Canyon is naturally high in salt (NaCl), which is known to prohibit development of external fish parasites such as Ich (Ichthyophthirius multifiliis). The naturally high salinity (>0.3%) of the Little Colorado River at baseflow may be one factor allowing survival and persistence of larval and juvenile humpback chub (Gila cypha) and other native fishes in Grand Canyon. We compared salinity readings from the Little Colorado River to those reported in the literature as being effective at removing protozoan parasites from fish. In laboratory tests, 10 juvenile roundtail chub (Gila robusta; 61–90 mm TL) were randomly placed into each of 12, 37-L aquaria filled with freshwater, water obtained from the Little Colorado River (0.3% salinity), or freshwater with table salt added until the salinity reached 0.3%. Roundtail chub was used as a surrogate for humpback chub in this study because the species is not listed as endangered but is morphologically and ecologically similar to humpback chub. All roundtail chub infected with Ich recovered and survived when placed in water from the Little Colorado River or water with 0.3% salinity, but all experimental fish placed in freshwater died because of Ich infection. The naturally high salinity of the Little Colorado River at baseflow (0.22%–0.36%), appears sufficiently high to interrupt the life cycle of Ich and may allow increased survival of larval and juvenile humpback chub relative to other areas within Grand Canyon.

  12. Wide-area estimates of stand structure and water use of tamarix spp. on the lower colorado river: Implications for restoration and water management projects

    Science.gov (United States)

    Nagler, P.L.; Glenn, E.P.; Didan, K.; Osterberg, J.; Jordan, F.; Cunningham, J.

    2008-01-01

    Tamarix spp. removal has been proposed to salvage water and allow native vegetation to recolonize western U.S. riparian corridors. We conducted wide-area studies on the Lower Colorado River to answer some of the scientific questions about Tamarix water use and the consequences of removal, combining ground surveys with remote sensing methods. Tamarix stands had moderate rates of evapotranspiration (ET), based on remote sensing estimates, averaging 1.1 m/yr, similar to rates determined for other locations on the river and other rivers. Leaf area index values were also moderate, and stands were relatively open, with areas of bare soil interspersed within stands. At three Tamarix sites in the Cibola National Wildlife Refuge, groundwater salinity at the site nearest to the river (200 m) was relatively low (circa 2,250 mg/L) and was within 3 m of the surface. However, 750 and 1,500 m from the river, the groundwater salinity was 5,000-10,000 mg/L due to removal of water by the Tamarix stands. Despite the high groundwater salinity, the sites away from the river did not have saline surface soils. Only 1% of the mean annual river flow is lost to Tamarix ET on the Lower Colorado River in the United States, and the opportunities for water salvage through Tamarix removal are constrained by its modest ET rates. A possible alternative to Tamarix removal is to intersperse native plants among the stands to improve the habitat value of the riparian zone. ?? 2008 Society for Ecological Restoration International.

  13. Geology of Paleozoic Rocks in the Upper Colorado River Basin in Arizona, Colorado, New Mexico, Utah, and Wyoming, Excluding the San Juan Basin

    Science.gov (United States)

    Geldon, Arthur L.

    2003-01-01

    The geology of the Paleozoic rocks in the Upper Colorado River Basin in Arizona, Colorado, New Mexico, Utah, and Wyoming, was studied as part of the U.S. Geological Survey's Regional Aquifer-System Analysis Program to provide support for hydrogeological interpretations. The study area is segmented by numerous uplifts and basins caused by folding and faulting that have recurred repeatedly from Precambrian to Cenozoic time. Paleozoic rocks in the study area are 0-18,000 feet thick. They are underlain by Precambrian igneous, metamorphic, and sedimentary rocks and are overlain in most of the area by Triassic formations composed mostly of shale. The overlying Mesozoic and Tertiary rocks are 0-27,000 feet thick. All Paleozoic systems except the Silurian are represented in the region. The Paleozoic rocks are divisible into 11 hydrogeologic units. The basal hydrogeologic unit consisting of Paleozoic rocks, the Flathead aquifer, predominantly is composed of Lower to Upper Cambrian sandstone and quartzite. The aquifer is 0-800 feet thick and is overlain gradationally to unconformably by formations of Cambrian to Mississippian age. The Gros Ventre confining unit consists of Middle to Upper Cambrian shale with subordinate carbonate rocks and sandstone. The confining unit is 0-1,100 feet thick and is overlain gradationally to unconformably by formations of Cambrian to Mississippian age. The Bighom aquifer consists of Middle Cambrian to Upper Ordovician limestone and dolomite with subordinate shale and sandstone. The aquifer is 0-3,000 feet thick and is overlain unconformably by Devonian and Mississipplan rocks. The Elbert-Parting confining unit consists of Lower Devonian to Lower Mississippian limestone, dolomite, sandstone, quartzite, shale, and anhydrite. It is 0-700 feet thick and is overlain conformably to unconformably by Upper Devonian and Mississippian rocks. The Madison aquifer consists of two zones of distinctly different lithology. The lower (Redwall-Leadville) zone

  14. Historical effects of El Nino and La Nina events on the seasonal evolution of the montane snowpack in the Columbia and Colorado River Basins

    Science.gov (United States)

    Clark, M.P.; Serreze, M.C.; McCabe, G.J.

    2001-01-01

    Snow-water equivalent (SWE) data measured at several hundred montane sites in the western United States are used to examine the historic effects of El Nino and La Nina events on seasonal snowpack evolution in the major subbasins in the Columbia and Colorado River systems. Results are used to predict annual runoff. In the Columbia River Basin, there is a general tendency for decreased SWE during El Nino years and increased SWE in La Nina years. However, the SWE anomalies for El Nino years are much less pronounced. This occurs in part because midlatitude circulation anomalies in El Nino years are located 35?? east of those in La Nina years. This eastward shift is most evident in midwinter, at which time, SWE anomalies associated with El Nino are actually positive in coastal regions of the Columbia River Basin. In the Colorado River Basin, mean anomalies in SWE and annual runoff during El Nino years depict a transition between drier-than-average conditions in the north, and wetter-than-average conditions in the southwest. Associations during La Nina years are generally opposite those in El Nino years. SWE anomalies tend to be more pronounced in spring in the Lower Colorado River Basin. Our predictions of runoff reveal modest skill for scenarios using only historic El Nino and La Nina information. Predictions based on the water stored in the seasonal snowpack are, in almost all cases, much higher than those based on El Nino-Southern Oscillation (ENSO) information alone. However, combining observed midwinter snow conditions with information on seasonal snowpack evolution associated with ENSO improves predictions for basins in which ENSO signals exhibit strong seasonality.

  15. Prediction of water flows in Colorado River, Argentina Predicción de caudales en río Colorado, Argentina

    OpenAIRE

    Pierini, Jorge O.; Gómez,Eduardo A; Luciano Telesca

    2012-01-01

    The identification of suitable models for predicting daily water flow is important for planning and management of water storage in reservoirs of Argentina. Long-term prediction of water flow is crucial for regulating reservoirs and hydroelectric plants, for assessing environmental protection and sustainable development, for guaranteeing correct operation of public water supply in cities like Catriel, 25 de Mayo, Colorado River and potentially also Bahía Blanca. In this paper, we analyze in Bu...

  16. Rhythmic bedding in prodeltaic deposits of the ancient Colorado River: Exploring genetic processes

    Science.gov (United States)

    Waresak, Sandra; Nalin, Ronald; Lucarelli, Andrea

    2016-04-01

    Prodeltaic deposits represent a valuable archive for the characterization of deltaic depositional systems, offering a distal, minimally reworked record of dominant processes active at the fluvial-marine interface. The Fish Creek Basin (CA, US) preserves a ~ 3-km thick, lower Pliocene, progradational deltaic succession formed when the ancestral Colorado River infiltrated a marine rift basin (the early Gulf of California). The unit in this succession interpreted as prodeltaic, corresponding to the upper Mud Hills Member of the Deguynos Formation, consists of ~ 300 m of muddy siltstones. A striking attribute of parts of this unit is the presence of rhythmic bedding, with consistently alternating silt- to fine sand-dominated and clay-dominated beds forming couplets with an average thickness of 12 cm. By performing a detailed sedimentological analysis of the rhythmites and investigating periodicities in bed thickness, our study aimed at reconstructing the mode of deposition of this enigmatic prodeltaic succession. We measured at high stratigraphic resolution 265 consecutive couplets, for a total thickness of 33 m. Individual beds have good lateral persistence of at least tens of meters and gradational to sharp, flat contacts. Observed sedimentary structures are concentrated on the coarser portion of the couplets and mostly consist of parallel and wavy lamination, with subordinate ripple cross-lamination and localized internal scours. Bioturbation appears low in intensity or absent. Most notably, grain size analysis performed with laser diffraction techniques on several couplets shows a consistent pattern of inverse grading transitioning to normal grading. The cumulative evidence of these sedimentological features indicates that deposition of the rhythmites was accomplished via hyperpycnal flows, each couplet most likely representing an individual event in a setting characterized by high overall depositional rates. We performed time series analysis on bed thickness of

  17. Flooding in the South Platte River and Fountain Creek Basins in eastern Colorado, September 9–18, 2013

    Science.gov (United States)

    Kimbrough, Robert A.; Holmes, Jr., Robert R.

    2015-11-25

    On September 9, 2013, rain began to fall in eastern Colorado as a large low-pressure system pulled plumes of tropical moisture northward from the Pacific Ocean and the Gulf of Mexico. By September 16, 2013, as much as 12 to 20 inches of rain had fallen in the foothills of the Front Range of the Southern Rocky Mountains and adjacent plains near Colorado Springs, Colorado, north to the Colorado-Wyoming border. The rain caused major flooding during September 9–18, 2013, in a large part of the South Platte River Basin and in the Fountain Creek Basin. The floods resulted in several fatalities, more than 31,000 damaged or destroyed structures, and an estimated 3 billion dollars in damages. The U.S. Geological Survey (USGS) documented peak stage, streamflow, or both from the flood event for 80 sites located on selected rivers and streams in the South Platte River and Fountain Creek Basins and on the Platte River in Nebraska. The majority of flood-peak streamflows occurred on September 12 or 13, 2013, coinciding with the period of maximum rainfall. The flood resulted in new record peak streamflows at 17 streamgages having at least 10 years of record; 13 in the South Platte River Basin and 4 in the Fountain Creek Basin.

  18. Geologic map of the Peach Orchard Flat quadrangle, Carbon County, Wyoming, and descriptions of new stratigraphic units in the Upper Cretaceous Lance Formation and Paleocene Fort Union Formation, eastern Greater Green River Basin, Wyoming-Colorado

    Science.gov (United States)

    Honey, J.D.; Hettinger, R.D.

    2004-01-01

    This report provides a geologic map of the Peach Orchard Flat 7.5-minute quadrangle, located along the eastern flank of the Washakie Basin, Wyo. Geologic formations and individual coal beds were mapped at a scale of 1:24,000; surface stratigraphic sections were measured and described; and well logs were examined to determine coal correlations and thicknesses in the subsurface. In addition, four lithostratigraphic units were named: the Red Rim Member of the Upper Cretaceous Lance Formation, and the China Butte, Blue Gap, and Overland Members of the Paleocene Fort Union Formation.

  19. Systems dynamic model to forecast salinity load to the Colorado River due to urbanization within the Las Vegas Valley.

    Science.gov (United States)

    Venkatesan, Arjun K; Ahmad, Sajjad; Johnson, Walter; Batista, Jacimaria R

    2011-06-01

    This study evaluates the impact of urban growth in the Las Vegas Valley (LVV), Nevada, USA on salinity of the Colorado River. In the past thirty eight years the LVV population has grown from 273,288 (1970) to 1,986,146 (2008). The wastewater effluents and runoff from the valley are diverted back to the Colorado River through the Las Vegas Wash (LVW). With the growth of the valley, the salinity released from urban areas has increased the level of TDS in the wastewater effluents, ultimately increasing the TDS in the Colorado River. The increased usage of water softeners in residential and commercial locations is a major contributor of TDS in the wastewater effluents. Controlling TDS release to the Colorado River is important because of the 1944 Treaty signed between the USA and Mexico. In addition, the agriculture salinity damage cost for the Colorado River has been estimated to be more than $306 a million per year using 2004 salinity levels. With the expected growth of LVV in coming years the TDS release into Lake Mead will increase over time. For this purpose, it is important to investigate future TDS release into the Colorado in anticipation of potential TDS reducing measures to be adopted. In this research, a dynamic simulation model was developed using system dynamics modeling to carry out water and TDS mass balances over the entire LVV. The dynamic model output agreed with historic data with an average error of 2%. Forecasts revealed that conservation efforts can reduce TDS load by 16% in the year 2035 when compared to the current trend. If total population using water softeners can be limited to 10% in the year 2035, from the current 30% usage, TDS load in the LVW can be reduced by 7%. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Flow-adjusted trends in dissolved selenium load and concentration in the Gunnison and Colorado Rivers near Grand Junction, Colorado, water years 1986--2008

    Science.gov (United States)

    Mayo, John W.; Leib, Kenneth J.

    2012-01-01

    As a result of elevated selenium concentrations, many western Colorado rivers and streams are on the U.S. Environmental Protection Agency 2010 Colorado 303(d) list, including the main stem of the Colorado River from the Gunnison River confluence to the Utah border. Selenium is a trace metal that bioaccumulates in aquatic food chains and can cause reproductive failure, deformities, and other adverse impacts in birds and fish, including several threatened and endangered fish species. Salinity in the upper Colorado River has been the focus of source-control efforts for many years. Although salinity loads and concentrations have been previously characterized at the U.S. Geological Survey (USGS) streamflow-gaging stations at the Gunnison River near Grand Junction, Colo., and at the Colorado River near the Colorado-Utah State line, trends in selenium load and concentration at these two stations have not been studied. The USGS, in cooperation with the Bureau of Reclamation and the Colorado River Water Conservation District, evaluated dissolved selenium (herein referred to as "selenium") load and concentration trends at these two sites to inform decision makers on the status and trends of selenium. This report presents results of the evaluation of trends in selenium load and concentration for two USGS streamflow-gaging stations: the Gunnison River near Grand Junction, Colo. ("Gunnison River site"), USGS site 09152500, and the Colorado River near Colorado-Utah State line ("Colorado River site"), USGS site 09163500. Flow-adjusted selenium loads were estimated for the beginning water year (WY) of the study, 1986, and the ending WY of the study, 2008. The difference between flow-adjusted selenium loads for WY 1986 and WY 2008 was selected as the method of analysis because flow adjustment removes the natural variations in load caused by changes in mean-daily streamflow, emphasizing human-caused changes in selenium load and concentration. Overall changes in human-caused effects

  1. Turbidity, light, temperature, and hydropeaking control primary productivity in the Colorado River, Grand Canyon

    Science.gov (United States)

    Hall, Robert O.; Yackulic, Charles B.; Kennedy, Theodore A.; Yard, Michael D.; Rosi-Marshall, Emma J.; Voichick, Nicholas; Behn, Kathrine E.

    2015-01-01

    Dams and river regulation greatly alter the downstream environment for gross primary production (GPP) because of changes in water clarity, flow, and temperature regimes. We estimated reach-scale GPP in five locations of the regulated Colorado River in Grand Canyon using an open channel model of dissolved oxygen. Benthic GPP dominates in Grand Canyon due to fast transport times and low pelagic algal biomass. In one location, we used a 738 days time series of GPP to identify the relative contribution of different physical controls of GPP. We developed both linear and semimechanistic time series models that account for unmeasured temporal covariance due to factors such as algal biomass dynamics. GPP varied from 0 g O2 m−2 d−1 to 3.0 g O2 m−2 d−1 with a relatively low annual average of 0.8 g O2 m−2d−1. Semimechanistic models fit the data better than linear models and demonstrated that variation in turbidity primarily controlled GPP. Lower solar insolation during winter and from cloud cover lowered GPP much further. Hydropeaking lowered GPP but only during turbid conditions. Using the best model and parameter values, the model accurately predicted seasonal estimates of GPP at 3 of 4 upriver sites and outperformed the linear model at all sites; discrepancies were likely from higher algal biomass at upstream sites. This modeling approach can predict how changes in physical controls will affect relative rates of GPP throughout the 385 km segment of the Colorado River in Grand Canyon and can be easily applied to other streams and rivers.

  2. Mexicali aquifer and its relation with the Colorado river and the Cerro Prieto geothermal reservoir

    Science.gov (United States)

    Ramirez-Hernandez, J.; Reyes-Lopez, J. A.; Carreon-Diazconti, C.; Lazaro-Mancilla, O.

    2008-05-01

    Until some years ago the Colorado River has been the main recharge source of the Mexicali and the Imperial Valley aquifers. River discharge interruption after the constructions of dams upstream (i.e. Parker, Davis and Hoover) and the creation of great irrigation systems in both Valleys have modified their dynamics. Currently, the distribution of water recharge is the network of irrigation and drainage channels that distribute water to more than 500.000 ha. The chemical quality of the recharge water also has changed because the irrigation run-off water has become more mineralized. On the other hand, the intense steam exploitation of the Cerro Prieto geothermal reservoir has inverted the flow direction from the Volcano Lagoon area that until the 60s constituted the discharge zone of the aquifer and the geothermal reservoir. In this work, changes in the aquifer water recharge regime, the phreatic level and the water chemical quality are analyzed. It was found that after the reduction of the annual water extraction from aquifer up to 750X106 m3, the static levels have reached a dynamic balance that could be altered if water seepage from the irrigation channels, specially from the All American Channel, is reduced. The total dissolved solids (TDS) concentration has increased from 1000 ppm in 1970 to 1800 ppm in 2005. The water of recent infiltration, the gradual cooling of the shallowest strata of the geothermal reservoir, and the almost total disappearance of the hydrothermal surface manifestations are evidences of groundwater flow inversion. The new source of groundwater recharge due to seepage of evaporation disposal geothermal brine pond is documented. This pond incorporates water with a very different chemical composition to the groundwater system. Therefore, mineralization of the shallow aquifer layers and the soil contamination process are identified. It was concluded that the aquifer hydrodynamics in the Valley of Mexicali depends on the irrigation system more

  3. Fossil clam shells reveal unintended carbon cycling consequences of Colorado River management

    Science.gov (United States)

    Smith, Jansen A.; Auerbach, Daniel A.; Flessa, Karl W.; Flecker, Alexander S.; Dietl, Gregory P.

    2016-09-01

    Water management that alters riverine ecosystem processes has strongly influenced deltas and the people who depend on them, but a full accounting of the trade-offs is still emerging. Using palaeoecological data, we document a surprising biogeochemical consequence of water management in the Colorado River basin. Complete allocation and consumptive use of the river's flow has altered the downstream estuarine ecosystem, including the abundance and composition of the mollusc community, an important component in estuarine carbon cycling. In particular, population declines in the endemic Colorado delta clam, Mulinia coloradoensis, from 50-125 individuals m-2 in the pre-dam era to three individuals m-2 today, have likely resulted in a reduction, on the order of 5900-15 000 t C yr-1 (4.1-10.6 mol C m-2 yr-1), in the net carbon emissions associated with molluscs. Although this reduction is large within the estuarine system, it is small in comparison with annual global carbon emissions. Nonetheless, this finding highlights the need for further research into the effects of dams, diversions and reservoirs on the biogeochemistry of deltas and estuaries worldwide, underscoring a present need for integrated water and carbon planning.

  4. On the contribution of groundwater storage to interannual streamflow anomalies in the Colorado River basin

    Directory of Open Access Journals (Sweden)

    E. A. Rosenberg

    2012-11-01

    Full Text Available We assess the significance of groundwater storage for seasonal streamflow forecasts by evaluating its contribution to interannual streamflow anomalies in the 29 tributary sub-basins of the Colorado River. Monthly and annual changes in total basin storage are simulated by two implementations of the Variable Infiltration Capacity (VIC macroscale hydrology model – the standard release of the model, and an alternate version that has been modified to include the SIMple Groundwater Model (SIMGM, which represents an unconfined aquifer underlying the soil column. These estimates are compared to those resulting from basin-scale water balances derived exclusively from observational data and changes in terrestrial water storage from the Gravity Recovery and Climate Experiment (GRACE satellites. Changes in simulated groundwater storage are then compared to those derived via baseflow recession analysis for 72 reference-quality watersheds. Finally, estimates are statistically analyzed for relationships to interannual streamflow anomalies, and predictive capacities are compared across storage terms. We find that both model simulations result in similar estimates of total basin storage change, that these estimates compare favorably with those obtained from basin-scale water balances and GRACE data, and that baseflow recession analyses are consistent with simulated changes in groundwater storage. Statistical analyses reveal essentially no relationship between groundwater storage and interannual streamflow anomalies, suggesting that operational seasonal streamflow forecasts, which do not account for groundwater conditions implicitly or explicitly, are likely not detrimentally affected by this omission in the Colorado River basin.

  5. Saltcedar (Tamarix spp.) Water Use and Ecohydrological Niches on the Lower Colorado River

    Science.gov (United States)

    Morino, K.; Nagler, P.; Didan, K.; Erker, J.; Osterberg, J.; Hultine, K.; Glenn, E.

    2008-12-01

    In many places along the lower Colorado River, saltcedar (Tamarix spp) has replaced native shrubs and trees. Some have advocated removing saltcedar to save water and create environments more favorable to native species. We believe that native species once covered the landscape at densities similar to current saltcedar densities and therefore utilized similar amounts of water; moreover, we hypothesized that saltcedar has invaded areas that have increased in salinity due to reduced flooding. To evaluate these hypotheses, we conducted a multi-faceted study at the Cibola National Wildlife Refuge (CNWR). Using satellite images and reprocessed aerial photographs, we found that the fraction of land covered (fc) with vegetation in 2005-2007 was similar to coverage by native vegetation in 1938. We compared sapflux measurements of native species to saltcedar, and compared soil salinity, ground water depth, and soil moisture across a 1300m transect perpendicular to the Colorado River. On-site measurements of water use and soil and aquifer properties confirmed that although saltcedar grows much better than native species in areas where salinity has increased, rates of transpiration are similar. Over the whole CNWR, projected annual evapotranspiration (ET) was 1.15 m yr-1, 47% of reference crop ET. We conclude that periodic annual flooding would be required to reestablish native vegetation and that water use might actually increase with reduced inhibition of saline ground water on water uptake by the native vegetation.

  6. On the contribution of groundwater storage to interannual streamflow anomalies in the Colorado River basin

    Directory of Open Access Journals (Sweden)

    E. A. Rosenberg

    2013-04-01

    Full Text Available We assess the significance of groundwater storage for seasonal streamflow forecasts by evaluating its contribution to interannual streamflow anomalies in the 29 tributary sub-basins of the Colorado River. Monthly and annual changes in total basin storage are simulated by two implementations of the Variable Infiltration Capacity (VIC macroscale hydrology model – the standard release of the model, and an alternate version that has been modified to include the SIMple Groundwater Model (SIMGM, which represents an unconfined aquifer underlying the soil column. These estimates are compared to those resulting from basin-scale water balances derived exclusively from observational data and changes in terrestrial water storage from the Gravity Recovery and Climate Experiment (GRACE satellites. Changes in simulated groundwater storage are then compared to those derived via baseflow recession analysis for 72 reference-quality watersheds. Finally, estimates are statistically analyzed for relationships to interannual streamflow anomalies, and predictive capacities are compared across storage terms. We find that both model simulations result in similar estimates of total basin storage change, that these estimates compare favorably with those obtained from basin-scale water balances and GRACE data, and that baseflow recession analyses are consistent with simulated changes in groundwater storage. Statistical analyses reveal essentially no relationship between groundwater storage and interannual streamflow anomalies, suggesting that operational seasonal streamflow forecasts, which do not account for groundwater conditions implicitly or explicitly, are likely not detrimentally affected by this omission in the Colorado River basin.

  7. Abundance trends and status of the Little Colorado River population of humpback chub

    Science.gov (United States)

    Coggins, L.G.; Pine, William E.; Walters, C.J.; Van Haverbeke, D. R.; Ward, D.; Johnstone, H.C.

    2006-01-01

    The abundance of the Little Colorado River population of federally listed humpback chub Gila cypha in Grand Canyon has been monitored since the late 1980s by means of catch rate indices and capture-recapture-based abundance estimators. Analyses of data from all sources using various methods are consistent and indicate that the adult population has declined since monitoring began. Intensive tagging led to a high proportion (>80%) of the adult population being marked by the mid-1990s. Analysis of these data using both closed and open abundance estimation models yields results that agree with catch rate indices about the extent of the decline. Survival rates for age-2 and older fish are age dependent but apparently not time dependent. Back-calculation of recruitment using the apparent 1990s population age structure implies periods of higher recruitment in the late 1970s to early 1980s than is now the case. Our analyses indicate that the U.S. Fish and Wildlife Service recovery criterion of stable abundance is not being met for this population. Also, there is a critical need to develop new abundance indexing and tagging methods so that early, reliable, and rapid estimates of humpback chub recruitment can be obtained to evaluate population responses to management actions designed to facilitate the restoration of Colorado River native fish communities. ?? Copyright by the American Fisheries Society 2006.

  8. The 2014 water release into the arid Colorado River delta and associated water losses by evaporation.

    Science.gov (United States)

    Daesslé, L W; van Geldern, R; Orozco-Durán, A; Barth, J A C

    2016-01-15

    For the first time in history, water was intentionally released for environmental purposes into the final, otherwise dry, 160-km stretch of the Colorado River basin, south of the Mexican border. Between March and May 2014 three pulses of water with a total volume of 132×10(6) m(3) were released to assess the restoration potential of endemic flora along its course and to reach its estuary. The latter had not received a sustained input of fresh water and nutrients from its main fluvial source for over 50 years because of numerous upstream dam constructions. During this pulse flow large amounts of water were lost and negligible amounts reached the ocean. While some of these water losses can be attributed to plant uptake and infiltration, we were able to quantify evaporation losses between 16.1 to 17.3% of the original water mass % within the first 80 km after the Morels Dam with water stable isotope data. Our results showed no evidence for freshwater reaching the upper Colorado River estuary and it is assumed that the pulse flow had only negligible influences on the coastal ecosystem. Future water releases that aim on ecological restoration need to become more frequent and should have larger volumes if more significant effects are to be established on the area.

  9. Effects of ambient metals concentrations on the benthic macroinvertebrate community in the Animas River, Colorado

    Energy Technology Data Exchange (ETDEWEB)

    Covington, S.M.; Parkhurst, B.R. [Cadmus Group Inc., Laramie, WY (United States); Perino, L. [Sunnyside Gold Corp., Silverton, CO (United States)

    1995-12-31

    The Upper Animas River is located in southern Colorado at approximately 9500 feet above mean sea level near the town of Silverton in San Juan County. It drains several first and second order creeks and gulches, many of which are subject to water quality impacts from natural sources of metals and acid mine drainage and mine tailings from historical mining activity. When the State of Colorado proposed new designated uses with more stringent metal standards for the Upper Animas River, Sunnyside Gold Corp was concerned that these new proposed designated uses and their associated standards were unattainable primarily because of existing poor ambient water quality. Studies were designed to address this and other issues. This presentation focuses on ambient metal concentrations and their effect on macroinvertebrate density and composition. Aluminum, cadmium, copper, iron, manganese, and zinc were measured in the water column and in the precipitate on the gravel-cobble substrates at each location. Macroinvertebrate samples were also collected at these locations. The trends in benthic macroinvertebrate community composition in relationship to metal concentration and distribution will be discussed.

  10. Impacts of golden alga Prymnesium parvum on fish populations in reservoirs of the upper Colorado River and Brazos River basins, Texas

    Science.gov (United States)

    VanLandeghem, Matthew M.; Farooqi, Mukhtar; Farquhar, B.; Patino, Reynaldo

    2013-01-01

    Several reservoirs in the upper Colorado River and Brazos River basins in Texas have experienced toxic blooms of golden alga Prymnesium parvum and associated fish kills since 2001. There is a paucity of information, however, regarding the population-level effects of such kills in large reservoirs, species-specific resistance to or recovery from kills, or potential differences in the patterns of impacts among basins. We used multiple before-after, control-impact analysis to determine whether repeated golden alga blooms have led to declines in the relative abundance and size structure of fish populations. Sustained declines were noted for 9 of 12 fish species surveyed in the upper Colorado River, whereas only one of eight species was impacted by golden alga in the Brazos River. In the upper Colorado River, White Bass Morone chrysops, White Crappie Pomoxis annularis, Largemouth Bass Micropterus salmoides, Bluegill Lepomis macrochirus, River Carpsucker Carpiodes carpio, Freshwater Drum Aplodinotus grunniens, Channel Catfish Ictalurus punctatus, Flathead Catfish Pylodictis olivaris, and Blue Catfish I. furcatus exhibited sustained declines in relative abundance, size structure, or both; Gizzard Shad Dorosoma cepedianum, Longnose Gar Lepisosteus osseus, and Common Carp Cyprinus carpio did not exhibit those declines. In the Brazos River, only the relative abundance of Blue Catfish was impacted. Overall, toxic golden alga blooms can negatively impact fish populations over the long-term, but the patterns of impact can vary considerably among river basins and species. In the Brazos River, populations of most fish species appear to be healthy, suggesting a positive angling outlook for this basin. In the upper Colorado River, fish populations have been severely impacted, and angling opportunities have been reduced. Basin-specific management plans aimed at improving water quality and quantity will likely reduce bloom intensity and allow recovery of fish populations to the

  11. Assessing Potential Implications of Climate Change for Long-Term Water Resources Planning in the Colorado River Basin, Texas

    Science.gov (United States)

    Munevar, A.; Butler, S.; Anderson, R.; Rippole, J.

    2008-12-01

    While much of the focus on climate change impacts to water resources in the western United States has been related to snow-dominated watersheds, lower elevation basins such as the Colorado River Basin in Texas are dependent on rainfall as the predominant form of precipitation and source of supply. Water management in these basins has evolved to adapt to extreme climatic and hydrologic variability, but the impact of climate change is potentially more acute due to rapid runoff response and subsequent greater soil moisture depletion during the dry seasons. The Lower Colorado River Authority (LCRA) - San Antonio Water System (SAWS) Water Project is being studied to conserve water, develop conjunctive groundwater supplies, and capture excess and unused river flows to meet future water needs for two neighboring regions in Texas. Agricultural and other rural water needs would be met on a more reliable basis in the lower Colorado River Basin through water conservation, surface water development and limited groundwater production. Surface water would be transferred to the San Antonio area to meet municipal needs in quantities still being evaluated. Detailed studies are addressing environmental, agricultural, socioeconomic, and engineering aspects of the project. Key planning activities include evaluating instream flow criteria, water quality, bay freshwater inflow criteria, surface water availability and operating approaches, agricultural conservation measures, groundwater availability, and economics. Models used to estimate future water availability and environmental flow requirements have been developed largely based on historical observed hydrologic data. This is a common approach used by water planners as well as by many regulatory agencies for permit review. In view of the project's 80-yr planning horizon, contractual obligations, comments from the Science Review Panel, and increased public and regulatory awareness of climate change issues, the project team is

  12. Stochastic modeling and its applications in selected sites in the Colorado River

    Science.gov (United States)

    He, Xiaotian

    Deposition is an important process in shaping the earth's surface. Most depositional processes involving turbulent flows in rivers, lakes and ocean margins are stochastic processes. Basic laws of fluid dynamics are reviewed as well as the scientific literature on fluid modeling to improve our understanding of the underlying dynamics of deposition of sediment in both theory and numerical experiments. Based upon probabilistic theory, fluid dynamics, and empirical formulas, a nonlinear partial differential equation (PDE) model of stochastic processes is developed. The model illustrates time-dependent stochastic processes in detail. Development of the model starts with a one-dimensional simple random walk and ends with a three-dimensional random walk that incorporates turbulence and drift terms. For processes that are simple random walk, the model's underlying equation becomes the familiar heat equation. The major advantage of the stochastic model is that through the introduction of randomness, it can simulate turbulence. The stochastic model is used to examine the effect of drift on the diffusion process. Deposition, erosion, and river flow patterns are discussed. The stochastic model is modified to incorporate erosion and other geological factors. The numerical implementation of the mathematical model is discussed in detail. Due to computational stability, the fully implicit scheme is selected. Historical data at three selected sites along the Grand Canyon part of the Colorado River is applied to investigate the "trustworthiness" of the mathematical model developed in this research. The three sites River Mile 1.5, River Mile 18.0 (also called Eighteen Mile Wash), and River Mile 72.4 (referred as to Unkar Creek) represent three typically different fluvial depositional environments, which are channel marginal depositional environment, flow separation depositional environment and lateral accumulative depositional environment. The first two sites are numerically

  13. A site-specific assessment of the risk of ammonia to endangered Colorado Pikeminnow and Razorback Sucker populations in the upper Colorado River adjacent to the Atlas Mill Tailings Pile, Moab, Utah

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Atlas Mill Tailings Pile is located adjacent to the Upper Colorado River near Moab, Utah. Milling of ore ceased in 1984 and the Atlas Corporation subsequently...

  14. Chemical contaminants, health indicators, and reproductive biomarker responses in fish from the Colorado River and its tributaries

    Science.gov (United States)

    Hinck, J.E.; Blazer, V.S.; Denslow, N.D.; Echols, K.R.; Gross, T.S.; May, T.W.; Anderson, P.J.; Coyle, J.J.; Tillitt, D.E.

    2007-01-01

    Common carp (Cyprinus carpio), black bass (Micropterus spp.), and channel catfish (Ictalurus punctatus) were collected from 14 sites in the Colorado River Basin (CRB) to document spatial trends in accumulative contaminants, health indicators, and reproductive biomarkers. Organochlorine residues, 2,3,7,8-tetrachlorodibenzo-p-dioxin-like activity (TCDD-EQ), and elemental contaminants were measured in composite samples of whole fish, grouped by species and gender, from each site. Selenium (Se) and mercury (Hg) concentrations in fish were elevated throughout the CRB, and pesticide concentrations were greatest in fish from agricultural areas in the Lower Colorado River and Gila River. Selenium concentrations exceeded toxicity thresholds for fish (> 1.0????g/g ww) at all CRB sites except the Gila River at Hayden, Arizona. Mercury concentrations were elevated (> 0.1????g/g ww) in fish from the Yampa River at Lay, Colorado; the Green River at Ouray National Wildlife Refuge (NWR), Utah and San Rafael, Utah; the San Juan River at Hogback Diversion, New Mexico; and the Colorado River at Gold Bar Canyon, Utah, Needles, California, and Imperial Dam, Arizona. Concentrations of p,p???-DDE were relatively high in fish from the Gila River at Arlington, Arizona (> 1.0????g/g ww) and Phoenix, Arizona (> 0.5????g/g ww). Concentrations of other formerly used pesticides including toxaphene, total chlordanes, and dieldrin were also greatest at these two sites but did not exceed toxicity thresholds. Currently used pesticides such as Dacthal, endosulfan, ??-HCH, and methoxychlor were also greatest in fish from the Gila River downstream of Phoenix. Total polychlorinated biphenyls (PCBs; > 0.11????g/g ww) and TCDD-EQs (> 5??pg/g ww) exceeded wildlife guidelines in fish from the Gila River at Phoenix. Hepatic ethoxyresorufin O-deethylase (EROD) activity was also relatively high in carp from the Gila River at Phoenix and in bass from the Green River at Ouray NWR. Fish from some sites showed

  15. Structure contours on top of Coal marker sands, the Deserado Study Area, Lower White River coal field, Colorado (desstrcg)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This is a shapefile and ARC/INFO coverage of the structure contours on top of the Coal marker sands in the Deserado Study area, Lower White River coal field, Colorado

  16. 33 CFR 100.1102 - Marine Events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and Headgate Dam...

    Science.gov (United States)

    2010-07-01

    ... Coast Guard-National Park Service agreement exists for both the Glen Canyon and Lake Mead National..., Nevada, from the Pioneer Hotel to the Edgewater Hotel. Laughlin Aquamoto Sports Challenge and Expo.... PDT. Where: That portion of the Colorado River near Laughlin, Nevada, from Davis Dam to Harrah's Hotel...

  17. 78 FR 13811 - Special Local Regulation; Annual Marine Events on the Colorado River, Between Davis Dam (Bullhead...

    Science.gov (United States)

    2013-03-01

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 100 Special Local Regulation; Annual Marine Events on the Colorado River, Between Davis Dam (Bullhead City, AZ) and Headgate Dam (Parker, AZ) Within the San Diego Captain of...

  18. 77 FR 70121 - Special Local Regulation; Annual Marine Events on the Colorado River Between Davis Dam (Bullhead...

    Science.gov (United States)

    2012-11-23

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 100 Special Local Regulation; Annual Marine Events on the Colorado River Between Davis Dam (Bullhead City, AZ) and Headgate Dam (Parker, AZ) Within the San Diego Captain of...

  19. 77 FR 67563 - Special Local Regulation; Annual Marine Events on the Colorado River, Between Davis Dam (Bullhead...

    Science.gov (United States)

    2012-11-13

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 100 Special Local Regulation; Annual Marine Events on the Colorado River, Between Davis Dam (Bullhead City, AZ) and Headgate Dam (Parker, AZ) Within the San Diego Captain of...

  20. Dust radiative forcing in snow of the Upper Colorado River Basin: 1. A 6 year record of energy balance, radiation, and dust concentrations

    Science.gov (United States)

    Painter, Thomas H.; Skiles, S. Mckenzie; Deems, Jeffrey S.; Bryant, Ann C.; Landry, Christopher C.

    2012-07-01

    Dust in snow accelerates snowmelt through its direct reduction of snow albedo and its further indirect reduction of albedo by accelerating the growth of snow grains. Since the westward expansion of the United States that began in the mid-19th century, the mountain snow cover of the Colorado River Basin has been subject to five-fold greater dust loading, largely from the Colorado Plateau and Great Basin. Radiative forcing of snowmelt by dust is not captured by conventional micrometeorological measurements, and must be monitored by a more comprehensive suite of radiation instruments. Here we present a 6 year record of energy balance and detailed radiation measurements in the Senator Beck Basin Study Area, San Juan Mountains, Colorado, USA. Data include broadband irradiance, filtered irradiance, broadband reflected flux, filtered reflected flux, broadband and visible albedo, longwave irradiance, wind speed, relative humidity, and air temperatures. The gradient of the snow surface is monitored weekly and used to correct albedo measurements for geometric effects. The snow is sampled weekly for dust concentrations in plots immediately adjacent to each tower over the melt season. Broadband albedo in the last weeks of snow cover ranged from 0.33 to 0.55 across the 6 years and two sites. Total end of year dust concentration in the top 3 cm of the snow column ranged from 0.23 mg g-1 to 4.16 mg g-1. These measurements enable monitoring and modeling of dust and climate-driven snowmelt forcings in the Upper Colorado River Basin.

  1. Assessment of dissolved-solids loading to the Colorado River in the Paradox Basin between the Dolores River and Gypsum Canyon, Utah

    Science.gov (United States)

    Shope, Christopher L.; Gerner, Steven J.

    2014-01-01

    Salinity loads throughout the Colorado River Basin have been a concern over recent decades due to adverse impacts on population, natural resources, and regional economics. With substantial financial resources and various reclamation projects, the salt loading to Lake Powell and associated total dissolved-solids concentrations in the Lower Colorado River Basin have been substantially reduced. The Colorado River between its confluence with the Dolores River and Lake Powell traverses a physiographic area where saline sedimentary formations and evaporite deposits are prevalent. However, the dissolved-solids loading in this area is poorly understood due to the paucity of water-quality data. From 2003 to 2011, the U.S. Geological Survey in cooperation with the U.S. Bureau of Reclamation conducted four synoptic sampling events to quantify the salinity loading throughout the study reach and evaluate the occurrence and impacts of both natural and anthropogenic sources. The results from this study indicate that under late-summer base-flow conditions, dissolved-solids loading in the reach is negligible with the exception of the Green River, and that variations in calculated loads between synoptic sampling events are within measurement and analytical uncertainties. The Green River contributed approximately 22 percent of the Colorado River dissolved-solids load, based on samples collected at the lower end of the study reach. These conclusions are supported by water-quality analyses for chloride and bromide, and the results of analyses for the stable isotopes of oxygen and deuterium. Overall, no significant sources of dissolved-solids loading from tributaries or directly by groundwater discharge, with the exception of the Green River, were identified in the study area.

  2. The Effects of Climate Change on the Hydrology and Water Resources of the Colorado River Basin

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, N.S.; Wood, A.W.; Voisin, N.; Lettenmaier, D.P.; Palmer, R.N. [Department of Civil and Environmental Engineering, 164 Wilcox Hall, P.O. Box 352700, University of Washington, Seattle, WA 98195-2700 (United States)

    2004-07-01

    The potential effects of climate change on the hydrology and water resources of the Colorado River basin are assessed by comparing simulated hydrologic and water resources scenarios derived from downscaled climate simulations of the U.S. Department of Energy/National Center for Atmospheric Research Parallel Climate Model (PCM) to scenarios driven by observed historical (1950-1999) climate. PCM climate scenarios include an ensemble of three 105-year future climate simulations based on projected 'business-as-usual' (BAU) greenhouse gas emissions and a control climate simulation based on static 1995 greenhouse gas concentrations. Downscaled transient temperature and precipitation sequences were extracted from PCM simulations, and were used to drive the Variable Infiltration Capacity (VIC) macroscale hydrology model to produce corresponding streamflow sequences. Results for the BAU scenarios were summarized into Periods 1, 2, and 3 (2010-2039, 2040-2069, 2070-2098). Average annual temperature changes for the Colorado River basin were 0.5C warmer for control climate, and 1.0, 1.7, and 2.4C warmer for Periods 1-3, respectively, relative to the historical climate. Basin-average annual precipitation for the control climate was slightly (1%) less than for observed historical climate, and 3, 6, and 3% less for future Periods 1-3, respectively. Annual runoff in the control run was about 10% lower than for simulated historical conditions, and 14, 18, and 17% less for Periods 1-3, respectively. Analysis of water management operations using a water management model driven by simulated streamflows showed that streamflows associated with control and future BAU climates would significantly degrade the performance of the water resources system relative to historical conditions, with average total basin storage reduced by 7% for the control climate and 36, 32 and 40% for Periods 1-3, respectively. Releases from Glen Canyon Dam to the Lower Basin (mandated by the Colorado

  3. Radiocarbon Depression in Aquatic Foodwebs of the Colorado River, USA: Coupling Between Carbonate Weathering and the Biosphere

    Science.gov (United States)

    Sickman, J. O.; Huang, W.; Lucero, D.; Anderson, M.

    2012-12-01

    The 14C isotopic composition of living organisms is generally considered to be in isotopic equilibrium with atmosphere CO2. During the course of investigations of aquatic foodwebs of the Colorado River, we measured substantial radiocarbon depression of organisms within planktonic and benthic foodwebs of Copper Basin Reservoir, a short residence-time water body at the intake to the Colorado River Aqueduct. All trophic levels had depressed radiocarbon content with inferred "age" of ca. 1,200 radiocarbon years (range: 0.85 to 0.87 fraction modern carbon (fmc)). Additional measurements of the radiocarbon content of dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) were made in other major rivers in California (New (near Salton Sea), Santa Ana (near Riverside), San Joaquin (near Fresno) and Salinas (near San Luis Obispo)). In the New River (which is composed primarily of irrigation tailwater derived from the Colorado River), the radiocarbon values for DIC closely matched those found in biota of the Copper Basin Reservoir (0.85 to 0.87 fmc), but radiocarbon values for DOC were slightly higher (0.91 to 0.95 fmc). In the other California rivers, radiocarbon concentrations in DIC were generally below modern and lower than corresponding levels in DOC; in the case of the Santa Ana River, DOC was older than DIC as a result of wastewater inputs from upstream treatment plants. Together these data suggest that the carbonate equilibrium of California rivers is influenced by weathering of carbonate minerals which produces HCO3- with no 14C. We hypothesize that this dead carbon can move into aquatic foodwebs via algae and phytoplankton uptake during photosynthesis, depressing the 14C content of aquatic foodwebs below that of the atmosphere. Based on a simple two-component mixing model incorporating carbonate weathering and atmospheric CO2, we estimate that 15-17% of the carbon in the aquatic foodweb of Copper Basin is derived directly from mineral weathering of

  4. Dams, floodplain land use, and riparian forest conservation in the semiarid Upper Colorado River Basin, USA

    Science.gov (United States)

    Andersen, D.C.; Cooper, D.J.; Northcott, K.

    2007-01-01

    Land and water resource development can independently eliminate riparian plant communities, including Fremont cottonwood forest (CF), a major contributor to ecosystem structure and functioning in semiarid portions of the American Southwest. We tested whether floodplain development was linked to river regulation in the Upper Colorado River Basin (UCRB) by relating the extent of five developed land-cover categories as well as CF and other natural vegetation to catchment reservoir capacity, changes in total annual and annual peak discharge, and overall level of mainstem hydrologic alteration (small, moderate, or large) in 26 fourth-order subbasins. We also asked whether CF appeared to be in jeopardy at a regional level. We classified 51% of the 57,000 ha of alluvial floodplain examined along >2600 km of mainstem rivers as CF and 36% as developed. The proportion developed was unrelated to the level of mainstem hydrologic alteration. The proportion classified as CF was also independent of the level of hydrologic alteration, a result we attribute to confounding effects from development, the presence of time lags, and contrasting effects from flow alteration in different subbasins. Most CF (68% by area) had a sparse canopy (???5% cover), and stands with >50% canopy cover occupied Springer Science+Business Media, LLC.

  5. Geomorphic changes resulting from floods in reconfigured gravel-bed river channels in Colorado, USA

    Science.gov (United States)

    Elliott, J.G.; Capesius, J.P.

    2009-01-01

    Geomorphic changes in reconfi gured reaches of three Colorado rivers in response to floods in 2005 provide a benchmark for "restoration" assessment. Sedimententrainment potential is expressed as the ratio of the shear stress from the 2 yr, 5 yr, 10 yr, and 2005 floods to the critical shear stress for sediment. Some observed response was explained by the excess of flood shear stress relative to the resisting force of the sediment. Bed-load entrainment in the Uncompahgre River and the North Fork Gunnison River, during 4 and 6 yr floods respectively, resulted in streambed scour, streambed deposition, lateral-bar accretion, and channel migration at various locations. Some constructed boulder and log structures failed because of high rates of bank erosion or bed-material deposition. The Lake Fork showed little or no net change after the 2005 flood; however, this channel had not conveyed floods greater than the 2.5 yr flood since reconfi guration. Channel slope and the 2 yr flood, a surrogate for bankfull discharge, from all three reconfi gured reaches plotted above the Leopold and Wolman channel-pattern threshold in the "braided channel" region, indicating that braiding, rather than a single-thread meandering channel, and midchannel bar formation may be the natural tendency of these gravel-bed reaches. When plotted against a total stream-power and median-sediment-size threshold for the 2 yr flood, however, the Lake Fork plotted in the "single-thread channel" region, the North Fork Gunnison plotted in the " multiplethread" region, and the Uncompahgre River plotted on the threshold. All three rivers plotted in the multiple-thread region for floods of 5 yr recurrence or greater. ?? 2009 Geological Society of America.

  6. Conditions and processes affecting sand resources at archeological sites in the Colorado River corridor below Glen Canyon Dam, Arizona

    Science.gov (United States)

    East, Amy E.; Collins, Brian D.; Sankey, Joel B.; Corbett, Skye C.; Fairley, Helen C.; Caster, Joshua

    2016-05-17

    This study examined links among fluvial, aeolian, and hillslope geomorphic processes that affect archeological sites and surrounding landscapes in the Colorado River corridor downstream from Glen Canyon Dam, Arizona. We assessed the potential for Colorado River sediment to enhance the preservation of river-corridor archeological resources through aeolian sand deposition or mitigation of gully erosion. By identifying locally prevailing wind directions, locations of modern sandbars, and likely aeolian-transport barriers, we determined that relatively few archeological sites are now ideally situated to receive aeolian sand supply from sandbars deposited by recent controlled floods. Whereas three-fourths of the 358 river-corridor archeological sites we examined include Colorado River sediment as an integral component of their geomorphic context, only 32 sites currently appear to have a high degree of connectivity (coupled interactions) between modern fluvial sandbars and sand-dominated landscapes downwind. This represents a substantial decrease from past decades, as determined by aerial-photograph analysis. Thus, we infer that recent controlled floods have had a limited, and declining, influence on archeological-site preservation.

  7. Calcite Supersaturation and Precipitation Kinetics in the Lower Colorado River, Ail-American Canal and East Highline Canal

    Science.gov (United States)

    Suarez, D. L.

    1983-06-01

    In situ pH determinations and analysis of major ions in solution indicated that the lower Colorado River is supersaturated with respect to calcite throughout the entire daily cycle, in both winter and summer. Although the ion activity product was 4 to 6 times greater than the calcite solubility product, there was no detectable precipitation. Chemical analyses of water samples taken along 350 km of the river and canals from Parker Dam to the Salton Sea also revealed no evidence of calcium carbonate precipitation despite the inflow of saline and highly supersaturated irrigation return flows. Laboratory kinetic studies indicated that calcite crystal growth rates with Colorado River water are about 30% of the rate for pure Ca-HCO3 waters and about 70% of that for synthetic Colorado River water. Calcite precipitation by crystal growth in the river is limited by the combination of short residence times and unavailability of reactive calcite. Critical supersaturation levels necessary for heterogeneous nucleation do not occur; a high suspended load limits algal photosynthesis and thus prevents large decreases in daytime H2CO3 levels.

  8. River Outflow of the Conterminous United States, 1939-1988.

    Science.gov (United States)

    Guetter, Alexandre K.; Georgakakos, Konstantine P.

    1993-10-01

    A record of 50 years of daily outflows through the boundaries of the continental United States has been assembled based on observations recorded by U.S. Geological Survey streamflow stations. Only stations with continuous records from 1939 through 1988 were included. These stations (197 total) are near the outlets of rivers located at the vicinity of the Canadian, Mexican, Atlantic (including the Gulf of Mexico), and Pacific borders of the continental United States. The drainage area of the selected stations covers 77% of the conterminous United States, whereas the existing network of gauging stations covers 83% of the conterminous U.S. area. Station daily data were aggregated over the entire boundary of the United States and were integrated in monthly and annual totals. The 50-year average annual streamflow divergence normalized by the aggregated drainage area is 210.2 mm yr1, reaching a peak in April with 27.3 mm month1 and a minimum in September with 8.7 mm month1. The Mississippi-Missouri Basin comprises 50% of the gauged area and dominates the absolute value of the outflow discharge. Spectral analysis of the monthly outflow anomalies shows an 11-year dominant cycle. The 1939-1988 period contains four notable droughts. Two droughts are partially registered in the limits of the records characterized by the negative anomalies extending from 1939 to 1941 and by the 1987-1988 anomalies for the late 1980s drought. The middle 1950s and early 1960s droughts are fully included in the dataset. Periods of high outflows were registered in the middle 1940s, early 1970s, and early 1980s. Analysis of the spatial coherence of the annual anomalies shows large-scale features, whereas analysis of the monthly anomalies yields the frequency and persistence patterns of floods and droughts. An estimate of the climatological land-surface water budget for the continental United States was done based on recorded precipitation, panevaporation, and outflow. Eigenvector analysis of the

  9. Groundwater Depletion During Drought Threatens Future Water Security of the Colorado River Basin

    Science.gov (United States)

    Castle, Stephanie L.; Thomas, Brian F.; Reager, John T.; Rodell, Matthew; Swenson, Sean C.; Famiglietti, James S.

    2014-01-01

    Streamflow of the Colorado River Basin is the most overallocated in the world. Recent assessment indicates that demand for this renewable resource will soon outstrip supply, suggesting that limited groundwater reserves will play an increasingly important role in meeting future water needs. Here we analyze 9 years (December 2004 to November 2013) of observations from the NASA Gravity Recovery and Climate Experiment mission and find that during this period of sustained drought, groundwater accounted for 50.1 cu km of the total 64.8 cu km of freshwater loss. The rapid rate of depletion of groundwater storage (5.6 +/- 0.4 cu km/yr) far exceeded the rate of depletion of Lake Powell and Lake Mead. Results indicate that groundwater may comprise a far greater fraction of Basin water use than previously recognized, in particular during drought, and that its disappearance may threaten the long-term ability to meet future allocations to the seven Basin states.

  10. Hydraulic, geomorphic, and trout habitat conditions of the Lake Fork of the Gunnison River in Hinsdale County, Lake City, Colorado, Water Years 2010-2011

    Science.gov (United States)

    Williams, Cory A.; Richards, Rodney J.; Schaffrath, Keelin R.

    2015-01-01

    Channel rehabilitation, or reconfiguration, to mitigate a variety of riverine problems has become a common practice in the western United States. However, additional work to monitor and assess the channel response to, and the effectiveness of, these modifications over longer periods of time (decadal or longer) is still needed. The Lake Fork of the Gunnison River has been an area of active channel modification to accommodate the needs of the Lake City community since the 1950s. The Lake Fork Valley Conservancy District began a planning process to assess restoration options for a reach of the Lake Fork in Lake City to enhance hydraulic and ecologic characteristics of the reach. Geomorphic channel form is affected by land-use changes within the basin and geologic controls within the reach. The historic channel was defined as a dynamic, braided channel with an active flood plain. This can result in a natural tendency for the channel to braid. A braided channel can affect channel stability of reconfigured reaches when a single-thread meandering channel is imposed on the stream. The U.S. Geological Survey, in cooperation with the Colorado Water Conservation Board and Colorado River Water Conservation District, began a study in 2010 to quantify existing hydraulic and habitat conditions for a reach of the Lake Fork of the Gunnison River in Lake City, Colorado. The purpose of this report is to quantify existing Lake Fork hydraulic and habitat conditions and establish a baseline against which post-reconfiguration conditions can be compared. This report (1) quantifies the existing hydraulic and geomorphic conditions in a 1.1-kilometer section of the Lake Fork at Lake City that has been proposed as a location for future channel-rehabilitation efforts, (2) characterizes the habitat suitability of the reach for two trout species based on physical conditions within the stream, and (3) characterizes the current riparian canopy density.

  11. Land Cover Information for the Upper Colorado River Basin in Maurer et al. (2002) Climate Data resolution (nlcd_UCRB_Maurer_resolution.asc)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — nlcd_UCRB_Maurer_resolution.asc is an Esri ASCII grid representing land cover information for the Upper Colorado River Basin. The 2011 National Land Cover Database...

  12. Hydrologic Soil Group for the Upper Colorado River Basin in Maurer et al. (2002) Climate Data resolution (hsg_UCRB_Maurer_resolution.asc)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — hsg_UCRB_Maurer_resolution.asc is an Esri ASCII grid representing the hydrologic soil group (HSG) for the Upper Colorado River Basin. The HSG for an area is...

  13. Overland Flow Direction Information for the Upper Colorado River Basin in Daymet Climate Data resolution (overland_flow_direction_UCRB_daymet_resolution.txt)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — overland_flow_direction_UCRB_daymet_resolution.txt is an Esri ASCII grid representing overland flow direction in the Upper Colorado River Basin using the D8...

  14. Available Water Capacity for the Upper Colorado River Basin in Maurer et al. (2002) Climate Data resolution (awc_UCRB_Maurer_resolution.asc)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — awc_UCRB_Maurer_resolution.asc is an Esri ASCII grid representing the available water capacity (AWC) for the Upper Colorado River Basin. AWC is the amount of water...

  15. Overland Flow Direction Information for the Upper Colorado River Basin in Maurer et al. (2002) Climate Data resolution (overland_flow_direction_UCRB_Maurer_resolution.asc)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — overland_flow_direction_UCRB_Maurer_resolution.asc is an Esri ASCII grid representing overland flow direction in the Upper Colorado River Basin using the D8...

  16. Dams, floodplain land use, and riparian forest conservation in the semiarid Upper Colorado River Basin, USA.

    Science.gov (United States)

    Andersen, Douglas C; Cooper, David J; Northcott, Krista

    2007-09-01

    Land and water resource development can independently eliminate riparian plant communities, including Fremont cottonwood forest (CF), a major contributor to ecosystem structure and functioning in semiarid portions of the American Southwest. We tested whether floodplain development was linked to river regulation in the Upper Colorado River Basin (UCRB) by relating the extent of five developed land-cover categories as well as CF and other natural vegetation to catchment reservoir capacity, changes in total annual and annual peak discharge, and overall level of mainstem hydrologic alteration (small, moderate, or large) in 26 fourth-order subbasins. We also asked whether CF appeared to be in jeopardy at a regional level. We classified 51% of the 57,000 ha of alluvial floodplain examined along >2600 km of mainstem rivers as CF and 36% as developed. The proportion developed was unrelated to the level of mainstem hydrologic alteration. The proportion classified as CF was also independent of the level of hydrologic alteration, a result we attribute to confounding effects from development, the presence of time lags, and contrasting effects from flow alteration in different subbasins. Most CF (68% by area) had a sparse canopy (50% canopy cover occupied <1% of the floodplain in 15 subbasins. We suggest that CF extent in the UCRB will decline markedly in the future, when the old trees on floodplains now disconnected from the river die and large areas change from CF to non-CF categories. Attention at a basinwide scale to the multiple factors affecting cottonwood patch dynamics is needed to assure conservation of these riparian forests.

  17. Flow and suspended-sediment transport in the Colorado River near National Canyon

    Science.gov (United States)

    Smith, J. Dungan

    Point measurements of flow speed and suspended-sand concentration were made from a cableway 293-km downstream from Glen Canyon Dam during the 1996 controlled flood. The data demonstrate a systematic fining of the suspended load in the Colorado River, a reduction in near-bed sand concentration with time, and a strong secondary circulation that very effectively transported suspended sand toward the channel margins. In the center of the river, the primary flow was well represented by steady, horizontally uniform flow theory, with a shear velocity of 0.081 m/s and a sand grain related roughness parameter of 4.5·1O-6 m; at the channel margins the primary flow exhibited a distinct internal boundary layer with a shear velocity of approximately 0.081 m/s and an outer boundary layer with a shear velocity of approximately twice that value. The secondary circulation was caused by long wavelength irregularities in the rockfall-produced sloping banks of the approximately trapezoidal channel. The primary flow was forced upward and toward the river center by these topographic features causing a fully 3-dimensional circulation. The upward forced vertical velocities apparently interacted with turbulence in the primary flow to produce boils. Consequently, the upwelling zone degraded to an irregular, bank-parallel boil line. Downwelling occurred over a broad region in the center of the river, but also was concentrated along well-defined convergence zones over which woody debris concentrated. This secondary circulation was very effective in transporting suspended sand toward the channel margins at the bottom, then lifting it in the boils and depositing it inshore of the boil line on the riverbanks.

  18. Parasites of fishes in the Colorado River and selected tributaries in Grand Canyon, Arizona.

    Science.gov (United States)

    Cole, Rebecca A.; Sterner, Mauritz C.; Linder, Chad; Hoffnagle, Timothy L.; Persons, Bill; Choudhury, Anindo; Haro, Roger

    2012-01-01

    As part of the endangered humpback chub (HBC; Gila cypha) Adaptive Management Program, a parasite survey was conducted from 28 June to 17 July 2006 in 8 tributaries and 7 adjacent sections of the main stem of the Colorado River, U.S.A. In total, 717 fish were caught, including 24 HBC. Field necropsies yielded 19 parasite species, 5 of which (Achtheres sp., Kathlaniidae gen. sp., Caryophyllaidae gen. sp., Myxidium sp., and Octomacrum sp.) are new records for Grand Canyon, Arizona, U.S.A. Spearman's correlation coefficient analyses showed no correlations between parasite burden and fork length for various combinations of fish and parasite species. Regression analyses suggest that no parasite species had a strong effect on fish length. The most diverse parasite community (n=14) was at river kilometer (Rkm) 230, near the confluence of Kanab Creek. The most diverse parasite infracommunity (n=12) was found in the non-native channel catfish (CCF; Ictaluris punctatus). Overall parasite prevalence was highest in CCF (85%) followed by that in HBC (58%). The parasite fauna of humpback chub was mainly composed of Bothriocephalus acheilognathi and Ornithodiplostomum sp. metacercariae.

  19. Modeled intermittency risk for small streams in the Upper Colorado River Basin under climate change

    Science.gov (United States)

    Reynolds, Lindsay V.; Shafroth, Patrick B.; Poff, N. LeRoy

    2015-01-01

    Longer, drier summers projected for arid and semi-arid regions of western North America under climate change are likely to have enormous consequences for water resources and river-dependent ecosystems. Many climate change scenarios for this region involve decreases in mean annual streamflow, late summer precipitation and late-summer streamflow in the coming decades. Intermittent streams are already common in this region, and it is likely that minimum flows will decrease and some perennial streams will shift to intermittent flow under climate-driven changes in timing and magnitude of precipitation and runoff, combined with increases in temperature. To understand current intermittency among streams and analyze the potential for streams to shift from perennial to intermittent under a warmer climate, we analyzed historic flow records from streams in the Upper Colorado River Basin (UCRB). Approximately two-thirds of 115 gaged stream reaches included in our analysis are currently perennial and the rest have some degree of intermittency. Dry years with combinations of high temperatures and low precipitation were associated with more zero-flow days. Mean annual flow was positively related to minimum flows, suggesting that potential future declines in mean annual flows will correspond with declines in minimum flows. The most important landscape variables for predicting low flow metrics were precipitation, percent snow, potential evapotranspiration, soils, and drainage area. Perennial streams in the UCRB that have high minimum-flow variability and low mean flows are likely to be most susceptible to increasing streamflow intermittency in the future.

  20. Airborne LiDAR and hyperspectral mapping of snow depth and albedo in the Upper Colorado River Basin, Colorado, USA by the NASA JPL Airborne Snow Observatory

    Science.gov (United States)

    Deems, J. S.; Painter, T. H.

    2014-12-01

    Operational hydrologic simulation and forecasting in snowmelt-dominated watersheds currently relies on indices of snow accumulation and melt from measurements at a small number of point locations or geographically-limited manual surveys. These data sources cannot adequately characterize the spatial distribution of snow depth/water equivalent, which is the primary determinant of snowpack volume and runoff rates. The NASA JPL Airborne Snow Observatory's airborne laser scanning system maps snow depth at high spatial and temporal resolutions, and is paired with a hyperspectral imager to provide an unprecedented snowpack monitoring capability and enabling a new operational paradigm. We present the initial results from this new application of multi-temporal LiDAR and hyperspectral mapping. During the snowmelt seasons of 2013 and 2014, the ASO mapped snow depth and albedo in the Uncompahgre River Basin in Colorado's Upper Colorado River Basin on a nominally monthly basis. These products enable an assessment and comparison of spatial snow accumulation and melt processes in two years with very different snowmelt hydrographs.

  1. Characteristics of streams and aquifers and processes affecting the salinity of water in the upper Colorado River basin, Texas

    Science.gov (United States)

    Slade, R.M.; Buszka, P.M.

    1994-01-01

    The upper Colorado River and some of its tributaries between Lake J.B. Thomas and O.H. Ivie Reservoir contain saline water (defined as water having dissolved-solids concentrations greater than 1,000 milligrams per liter). Dissolved-solids loads at nine streamflow water-quality stations increased from 1986 to 1988. The largest increases were in Beals Creek and in the Colorado River downstream from Beals Creek as a result of outflow of saline water from Natural Dam Salt Lake. The outflow contained 654,000 tons of dissolved solids and had a mean dissolved-solids concentration of 7,900 milligrams per liter. This amount represents about 51 percent of the dissolved-solids load to E.V. Spence Reservoir during 1986-88.

  2. Estimating groundwater dynamics at a Colorado River floodplain site using historical hydrological data and climate information

    Science.gov (United States)

    Chen, Jinsong; Hubbard, Susan S.; Williams, Kenneth H.; Ficklin, Darren L.

    2016-03-01

    Long-term prediction of groundwater dynamics is important for assessing water resources and their impacts on biogeochemical cycling. However, estimating future groundwater dynamics is challenging due to the wide range of spatiotemporal scales in hydrological processes and uncertainty in future climate conditions. In this study, we develop a Bayesian model to combine small-scale historical hydrological data with large-scale climate information to estimate groundwater dynamics at a floodplain site in Rifle, Colorado. Although we have only a few years of groundwater elevation measurements, we have 47 years of streamflow data from a gaging station approximately 43 km upstream and long-term climate prediction on the Upper Colorado River Basin. To estimate future daily groundwater dynamics, we first develop a time series model to downscale the monthly streamflow derived from climate information to daily streamflow, and then transform the daily streamflow to groundwater dynamics at the downstream floodplain site. We use Monte Carlo methods to estimate future groundwater dynamics at the site through sampling from the joint posterior probability distribution. The results suggest that although future groundwater levels are expected to be similar to the current levels, the timing of the high groundwater levels is predicted to occur about 1 month earlier. The developed framework is extendable to other sites to estimate future groundwater dynamics given disparate data sets and climate projections. Additionally, the obtained estimates are being used as input to a site-specific watershed reactive transport models to predict how climate-induced changes will influence future biogeochemical cycling relevant to a variety of ecosystem services.

  3. Groundwater response to the 2014 pulse flow in the Colorado River Delta

    Science.gov (United States)

    Kennedy, Jeffrey; Rodriguez-Burgueno, Eliana; Ramirez-Hernandez, Jorge

    2017-01-01

    During the March-May 2014 Colorado River Delta pulse flow, approximately 102 × 106 m3 (82,000 acre-feet) of water was released into the channel at Morelos Dam, with additional releases further downstream. The majority of pulse flow water infiltrated and recharged the regional aquifer. Using groundwater-level and microgravity data we mapped the spatial and temporal distribution of changes in aquifer storage associated with pulse flow. Surface-water losses to infiltration were greatest around the Southerly International Boundary, where a lowered groundwater level owing to nearby pumping created increased storage potential as compared to other areas with shallower groundwater. Groundwater levels were elevated for several months after the pulse flow but had largely returned to pre-pulse levels by fall 2014. Elevated groundwater levels in the limitrophe (border) reach extended about 2 km to the east around the midway point between the Northerly and Southerly International Boundaries, and about 4 km to the east at the southern end. In the southern part of the delta, although total streamflow in the channel was less due to upstream infiltration, augmented deliveries through irrigation canals and possible irrigation return flows created sustained increases in groundwater levels during summer 2014. Results show that elevated groundwater levels and increases in groundwater storage were relatively short lived (confined to calendar year 2014), and that depressed water levels associated with groundwater pumping around San Luis, Arizona and San Luis Rio Colorado, Sonora cause large, unavoidable infiltration losses of in-channel water to groundwater in the vicinity.

  4. Origin and microfossils of the oil shale of the Green River formation of Colorado and Utah

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, W.H.

    1931-01-01

    The Green River formation of Colorado and Utah is a series of lakebeds of middle Eocene age that occupy two broad, shallow, simple, structural basins--the Piceance Creek basin in northwestern Colorado and the Uinta basin in northeastern Utah. The ancient lakes served as a basin for the accumulation of tremendous quantities of aquatic organisms. The predominance of microscopic fresh-water algae and protozoa over the remains of land plants, pollens and spores suggests that the greater part of the organic matter was derived from microorganisms that grew in the lakes. The pollens and spores were carried into the lakes by wind. Fish, mollusks, crustaceans, and aquatic insect larvae were also plentiful; and turtles, crocodiles, birds, small camels, and insects may have contributed to the organic matter. The ancient lakes apparently were shallow and had a large area, compared with depth. The abundance of organisms and the decaying organic matter produced a strongly reducing environment. Mechanical and chemical action, such as the mastication and digestion of the organic material by bottom-living organisms, caused disintegration of the original organic matter. When the residue was reduced to a gelatinous condition, it apparently resisted further bacterial decay, and other organisms accidently entombed in the gel were protected from disintegration. An accumulation of inorganic material occurred simultaneously with the disintegration of the organic ooze, and the entire mass became lithified. After most of the oil shale was deposited, the lake reverted nearly to the conditions that prevailed during its early stage, when the marlstone and low-grade oil shale of the basal member were formed. The streams in the vicinity of the lake were rejuvenated and carried great quantities of medium- to coarse-grained sand into the basin and formed a thick layer over the lakebeds.

  5. Evaluation of Metal Toxicity in Streams Affected by Abandoned Mine Lands, Upper Animas River Watershed, Colorado

    Science.gov (United States)

    Besser, John M.; Allert, Ann L.; Hardesty, Douglas K.; Ingersoll, Christopher G.; May, Thomas W.; Wang, Ning; Leib, Kenneth J.

    2001-01-01

    Acid drainage from abandoned mines and from naturally-acidic rocks and soil in the upper Animas River watershed of Colorado generates elevated concentrations of acidity and dissolved metals in stream waters and deposition of metal-contaminated particulates in streambed sediments, resulting in both toxicity and habitat degradation for stream biota. High concentrations of iron (Fe), aluminum (Al), zinc (Zn), copper (Cu), cadmium (Cd), and lead (Pb) occur in acid streams draining headwaters of the upper Animas River watershed, and high concentrations of some metals, especially Zn, persist in circumneutral reaches of the Animas River and Mineral Creek, downstream of mixing zones of acid tributaries. Seasonal variation of metal concentrations is reflected in variation in toxicity of stream water. Loadings of dissolved metals to the upper Animas River and tributaries are greatest during summer, during periods of high stream discharge from snowmelt and monsoonal rains, but adverse effects on stream biota may be greater during winter low-flow periods, when stream flows are dominated by inputs of groundwater and contain greatest concentrations of dissolved metals. Fine stream-bed sediments of the upper Animas River watershed also contain elevated concentrations of potentially toxic metals. Greatest sediment metal concentrations occur in the Animas River upstream from Silverton, where there are extensive deposits of mine and mill tailings, and in mixing zones in the Animas River and lower Mineral Creek, where precipitates of Fe and Al oxides also contain high concentrations of other metals. This report summarizes the findings of a series of toxicity studies in streams of the upper Animas River watershed, conducted on-site and in the laboratory between 1998 and 2000. The objectives of these studies were: (1) to determine the relative toxicity of stream water and fine stream-bed sediments to fish and invertebrates; (2) to determine the seasonal range of toxicity in stream

  6. Measuring and Scaling Evapotranspiration of a Cottonwood Restoration Plot on the Lower Colorado River

    Science.gov (United States)

    Nagler, P. L.; Jetton, A.; Fleming, J. B.; Glenn, E. P.; Erker, J.; Morino, K.; Milliken, J. A.; Gloss, S. P.

    2006-05-01

    Evapotranpsiration (ET) by riparian vegetation is the second largest water user on western U.S. rivers. Efforts are underway to create restoration plots containing native trees such as cottonwood (Populus fremontii) (CW) because they provide valuable wildlife habitat. Up to now, estimates of riparian ET have been based on indirect methods and validation of estimates has been difficult. At Cibola NWR on the Colorado River, we estimated ET for a 20 acre plot of 3 year old CW trees for 50 consecutive days, July 25 - Sept 15, 2005. We measured transpiration rate using sap flow, heat-balance methods to get sap flow on pairs of branches on 20 CW trees. We scaled these ground measurements to high resolution (0.3 m) aerial readings and then to the satellite-level using Landsat ETM+ (30m) and EOS-1 Terra MODIS (250m) pixels. Using regression equations developed in Nagler et al. (2005a,b), we predicted ET at this CW site based on local, maximum air temperatures and ETM+ and MODIS Enhanced Vegetation Index (EVI) data. Sap flow rates ranged from 6 mm d-1 to 10 mm d-1. Results projected by MODIS imagery were similar to rates measured by sap flow sensors. Scaled over the whole plantation, annual ET rates were projected to be 1.33 m yr-1 (4.3 ft yr-1), approximately 50% higher than saltcedar on this river system. We conclude that replacing saltcedar with CW may result in increased water demand and the efficacy in supporting wildlife should be validated before they are widely implemented as a restoration strategy.

  7. Structure contour map of the greater Green River basin, Wyoming, Colorado, and Utah

    Science.gov (United States)

    Lickus, M.R.; Law, B.E.

    1988-01-01

    The Greater Green River basin of Wyoming, Colorado, and Utah contains five basins and associated major uplifts (fig. 1). Published structure maps of the region have commonly used the top of the Lower Cretaceous Dakota Sandstone as a structural datum (Petroleum Ownership Map Company (POMCO), 1984; Rocky Mountain Association of Geologists, 1972). However, because relatively few wells in this area penetrate the Dakota, the Dakota structural datum has to be constructed by projecting down from shallower wells. Extrapolating in this manner may produce errors in the map. The primary purpose of this report is to present a more reliable structure contour map of the Greater Green River basin based on datums that are penetrated by many wells. The final map shows the large- to small-scale structures present in the Greater Green River basin. The availability of subsurface control and the map scale determined whether or not a structural feature was included on the map. In general, large structures such as the Moxa arch, Pinedale anticline, and other large folds were placed on the map based solely on the structure contours. In comparison, smaller folds and some faults were placed on the map based on structure contours and other reports (Bader 1987; Bradley 1961; Love and Christiansen, 1985; McDonald, 1975; Roehler, 1979; Wyoming Geological Association Oil and Gas Symposium Committee, 1979). State geologic maps and other reports were used to position basin margin faults (Bryant, 1985; Gries, 1983a, b; Hansen 1986; Hintze, 1980; Love and Christiansen, 1985; Tweto, 1979, 1983). In addition, an interpreted east-west-trending regional seismic line by Garing and Tainter (1985), which shows the basin configuration in cross-section, was helpful in locating buried faults, such as the high-angle reverse or thrust fault along the west flank of the Rock Springs uplift.

  8. Water velocity and the nature of critical flow in large rapids on the Colorado River, Utah

    Science.gov (United States)

    Magirl, C.S.; Gartner, J.W.; Smart, G.M.; Webb, R.H.

    2009-01-01

     Rapids are an integral part of bedrock-controlled rivers, influencing aquatic ecology, geomorphology, and recreational value. Flow measurements in rapids and high-gradient rivers are uncommon because of technical difficulties associated with positioning and operating sufficiently robust instruments. In the current study, detailed velocity, water surface, and bathymetric data were collected within rapids on the Colorado River in eastern Utah. With the water surface survey, it was found that shoreline-based water surface surveys may misrepresent the water surface slope along the centerline of a rapid. Flow velocities were measured with an ADCP and an electronic pitot-static tube. Integrating multiple measurements, the ADCP returned velocity data from the entire water column, even in sections of high water velocity. The maximum mean velocity measured with the ADCP was 3.7 m/s. The pitot-static tube, while capable of only point measurements, quantified velocity 0.39 m below the surface. The maximum mean velocity measured with the pitot tube was 5.2 m/s, with instantaneous velocities up to 6.5 m/s. Analysis of the data showed that flow was subcritical throughout all measured rapids with a maximum measured Froude number of 0.7 in the largest measured rapids. Froude numbers were highest at the entrance of a given rapid, then decreased below the first breaking waves. In the absence of detailed bathymetric and velocity data, the Froude number in the fastest-flowing section of a rapid was estimated from near-surface velocity and depth soundings alone.

  9. The implications of climate change scenario selection for future streamflow projection in the Upper Colorado River Basin

    OpenAIRE

    B. L. Harding; A. W. Wood; Prairie, J. R.

    2012-01-01

    The impact of projected 21st century climate conditions on streamflow in the Upper Colorado River Basin was estimated using a multi-model ensemble approach wherein the downscaled outputs of 112 future climate projections from 16 global climate models (GCMs) were used to drive a macroscale hydrology model. By the middle of the century, the impacts on streamflow range, over the entire ensemble, from a decrease of approximately 30% to an increase of approximately the same magnitude. Although pri...

  10. Skill Assessment of Water Supply Outlooks in the Colorado River Basin

    Directory of Open Access Journals (Sweden)

    Brent Harrison

    2015-07-01

    Full Text Available Water-supply outlooks that predict the April through July (snowmelt runoff and assist in estimating the total water-year runoff, are very important to users that rely on the major contributing watersheds of the Colorado River. This study reviewed the skill level of April through July forecasts at 28 forecast points within the Colorado River basin. All the forecasts were made after 1950, with considerable variation in time period covered. Evaluations of the forecasts were made using summary measures, correlation measures and categorical measures. The summary measure, a skill score for mean absolute error, indicated a steady increase in forecast skill through the forecast season of January to May. The width of the distribution for each monthly forecast over the 28 locations remained similar through the forecast season. The Nash-Sutcliffe score, a correlation measure, showed similar results, with the Nash-Sutcliffe median showing an increase from 0.4 to 0.8 during the forecast season. The categorical measures used a three-section partition of the April through July runoff. The Probability of Detection for low and high flows showed an increase in skill from approx. 0.4 to 0.8 during the forecast season. The same score for mid-flow years showed limited increase in skill. The low False Alarm Rate illustrated the under forecast of high-flow years. The Bias of the mid-runoff forecasts indicated over forecast early in the forecast season (January to March, with lower Bias later in the forecast season (April and May, ending the forecast season at 1.0, indicating no Bias. Forecasts for both low and high runoff were under forecast early in the season with a Bias near 0.5, improving to nearly 1.0 by the end of the forecast season. The Hit Rate measure illustrated the difficulty of mid-flow forecasts, starting at 0.5 in January and increasing to 0.75 in May due to the forecasting assumption of normal climatology for the remaining forecast period. There was no

  11. Intercomparison of global river discharge simulations focusing on dam operation—multiple models analysis in two case-study river basins, Missouri-Mississippi and Green-Colorado

    Science.gov (United States)

    Masaki, Yoshimitsu; Hanasaki, Naota; Biemans, Hester; Müller Schmied, Hannes; Tang, Qiuhong; Wada, Yoshihide; Gosling, Simon N.; Takahashi, Kiyoshi; Hijioka, Yasuaki

    2017-05-01

    We performed an intercomparison of river discharge regulated by dams under four meteorological forcings among five global hydrological models for a historical period by simulation. This is the first global multimodel intercomparison study on dam-regulated river flow. Although the simulations were conducted globally, the Missouri-Mississippi and Green-Colorado Rivers were chosen as case-study sites in this study. The hydrological models incorporate generic schemes of dam operation, not specific to a certain dam. We examined river discharge on a longitudinal section of river channels to investigate the effects of dams on simulated discharge, especially at the seasonal time scale. We found that the magnitude of dam regulation differed considerably among the hydrological models. The difference was attributable not only to dam operation schemes but also to the magnitude of simulated river discharge flowing into dams. That is, although a similar algorithm of dam operation schemes was incorporated in different hydrological models, the magnitude of dam regulation substantially differed among the models. Intermodel discrepancies tended to decrease toward the lower reaches of these river basins, which means model dependence is less significant toward lower reaches. These case-study results imply that, intermodel comparisons of river discharge should be made at different locations along the river's course to critically examine the performance of hydrological models because the performance can vary with the locations.

  12. Effects of drought on birds and riparian vegetation in the Colorado River Delta, Mexico

    Science.gov (United States)

    Hinojosa-Huerta, Osvel; Nagler, Pamela L.; Carrillo-Guererro, Yamilett K.; Glenn, Edward P.

    2013-01-01

    The riparian corridor in the delta of the Colorado River in Mexico supports internationally important bird habitat. The vegetation is maintained by surface flows from the U.S. and Mexico and by a high, non-saline aquifer into which the dominant phreatophytic shrubs and trees are rooted. We studied the effects of a regional drought on riparian vegetation and avian abundance and diversity from 2002 to 2007, during which time surface flows were markedly reduced compared to the period from 1995 to 2002. Reduced surface flows led to a reduction in native tree cover but an increase in shrub cover, mostly due to an increase in Tamarix spp., an introduced halophytic shrub, and a reduction in Populus fremontii and Salix gooddingii trees. However, overall vegetation cover was unchanged at about 70%. Overall bird density and diversity were also unchanged, but riparian-obligate species tended to decrease in abundance, and generalist species increased. Although reduction in surface flows reduced habitat value and negatively impacted riparian-obligate bird species, portions of the riparian zone exhibited resilience. Surface flows are required to reduce soil salt levels and germinate new cohorts of native trees, but the main source of water supporting this ecosystem is the aquifer, derived from underflows from irrigated fields in the U.S. and Mexico. The long-term prospects for delta riparian habitats are uncertain due to expected reduced flows of river water from climate change, and land use practices that will reduce underflows to the riparian aquifer and increase salinity levels. Active restoration programs would be needed if these habitats are to be preserved for the future.

  13. Understanding controls on redox processes in floodplain sediments of the Upper Colorado River Basin

    Energy Technology Data Exchange (ETDEWEB)

    Noël, Vincent; Boye, Kristin; Kukkadapu, Ravi K.; Bone, Sharon; Lezama Pacheco, Juan S.; Cardarelli, Emily; Janot, Noémie; Fendorf, Scott; Williams, Kenneth H.; Bargar, John R.

    2017-12-01

    River floodplains, heavily used for water supplies, housing, agriculture, mining, and industry, may have water quality jeopardized by native or exogenous metals. Redox processes mediate the accumulation and release of these species in groundwater. Understanding the physicochemical, hydrological, and biogeochemical controls on the distribution and variability and variability of redox conditions is therefore critical to developing conceptual and numerical models of contaminants transport within floodplains. The distribution and intensity of redox activity at the Rifle, CO, site within the Upper Colorado River Basin (UCRB), are believed to be controlled by textural and compositional heterogeneities. Regionally, the UCRB is impacted by former uranium and vanadium ore processing, resulting in contaminations by U, Mo, V, As, Se, and Mn. Floodplains throughout the UCRB share sediment and groundwater characteristics, making redox activity regionally important to metal and radionuclide mobility. In this study, Fe and S speciation were used to track the distribution and stability of redox processes in sediment cores from three floodplain sites covering a 250 km range in the central portion of the UCRB. The results of the present study support the hypothesis that Fe(III) and sulfate reducing sediments are regionally important in the UCRB. The presence of organic carbon together with pore saturation were the key requirements for reducing conditions, dominated by sulfate-reduction. Sediment texture moderated the response of the system to external forcing, such as oxidant infusion, making fine-grain sediments resistant to change in comparison to coarser-grained sediments. Exposure to O2 and NO3- mediates the reactivity and longevity of freshly precipitated sulfides creating the potential for release of sequestered radionuclides and metals. The physical and chemical parameters of reducing zones evidenced in this study are thus thought to be key parameters on the dynamic exchange

  14. Implications of Colorado river (Texas, USA) freshwater inflow to benthic ecosystem dynamics: A modeling study

    Science.gov (United States)

    Kim, Hae-Cheol; Montagna, Paul A.

    2009-08-01

    Estuaries are defined by mixing of freshwater from rivers and saltwater from seas. Water resource development can reduce river flows to the coast, but it is difficult to predict effects on estuaries. The Lavaca-Colorado Estuary is a major estuarine system along the Texas coast that provides major economic benefit to the region by supporting a variety of agricultural, residential, industrial, and recreational functions. New water projects could divert freshwater from Matagorda Bay. So, what environmental effects could result from further changes to inflow patterns in the Matagorda Bay system? To answer this question, a bioenergetic model, calibrated using a long-term dataset of benthic biomass, was run to investigate dynamics of macrobenthic biomass related to salinity regimes in the estuary. The model simulation results were interpreted to assess the role of freshwater inflow in controlling benthic productivity. Simulations, based on calibrated parameters (1988-1999), were run for a long-term period from 1988 to 2005. The model performance was found to be promising with the best percent root mean square (RMS) difference being 63% and worst being 92%. Sensitivity tests for the benthic responses to changes in salinity show that, in general, when salinity increased with decreasing nutrient concentrations, deposit feeder biomass increased while suspension feeder biomass decreased. Estuary-wide comparison predicts that reducing freshwater inflow may cause the upper and lower bay communities to respond in different ways. Reduced inflow to Lavaca Bay would result in decreasing benthic biomass; whereas, in Matagorda Bay, biomass would increase. Also, functional diversity would decrease in both bays with decreasing inflow. These effects are probably due to the benthic community acclimating to different salinity regimes, or more (or less) salt tolerant species populating the area. It is concluded that freshwater inflow plays an important role in maintaining the observed

  15. Parasites of native and nonnative fishes of the Little Colorado River, Grand Canyon, Arizona

    Science.gov (United States)

    Choudhury, A.; Hoffnagle, T.L.; Cole, R.A.

    2004-01-01

    A 2-yr, seasonal, parasitological study of 1,435 fish, belonging to 4 species of native fishes and 7 species of nonnative fishes from the lower Little Colorado River (LCR) and tributary creeks, Grand Canyon, Arizona, yielded 17 species of parasites. These comprised 1 myxozoan (Henneguya exilis), 2 copepods (Ergasilus arthrosis and Lernaea cyprinacea), 1 acarine (Oribatida gen. sp.), 1 piscicolid leech (Myzobdella lugubris), 4 monogeneans (Gyrodactylus hoffmani, Gyrodactylus sp., Dactylogyrus extensus, and Ligictaluridus floridanus), 4 nematodes (Contracaecum sp., Eustrongylides sp., Rhabdochona sp., and Truttaedacnitis truttae), 3 cestodes (Bothriocephalus acheilognathi, Corallobothrium fimbriatum, and Megathylacoides giganteum), and 2 trematodes (Ornithodiplostomum sp. and Posthodiplostomum sp.). Rhabdochona sp. was the only adult parasite native to the LCR. Infection intensities of Ornithodiplostomum sp. and B. acheilognathi were positively correlated with length of the humpback chub Gila cypha. Adult helminths showed a high degree of host specificity, except B. acheilognathi, which was recovered from all fish species examined but was most abundant in cyprinids. Abundance of B. acheilognathi in the humpback chub was highest in the fall and lowest in the summer in both reaches of the LCR. There was no major taxonomic difference in parasite assemblages between the 2 different reaches of the river (LC1 and LC2). Parasite community diversity was very similar in humpback chub, regardless of sampling site or time. The parasite fauna of the LCR is numerically dominated by B. acheilognathi and metacercariae of Ornithodiplostomum sp. The richest and most diverse component community occurred in a nonnative species, the channel catfish Ictalurus punctatus, but infracommunity species richness was highest in a native host, humpback chub.

  16. Functional traits and ecological affinities of riparian plants along the Colorado River in Grand Canyon

    Science.gov (United States)

    Palmquist, Emily C.; Ralston, Barbara; Sarr. Daniel,; Merritt, David; Shafroth, Patrick B; Scott, Julian

    2017-01-01

    Trait-based approaches to vegetation analyses are becoming more prevalent in studies of riparian vegetation dynamics, including responses to flow regulation, groundwater pumping, and climate change. These analyses require species trait data compiled from the literature and floras or original field measurements. Gathering such data makes trait-based research time intensive at best and impracticable in some cases. To support trait-based analysis of vegetation along the Colorado River through Grand Canyon, a data set of 20 biological traits and ecological affinities for 179 species occurring in that study area was compiled. This diverse flora shares species with many riparian areas in the western USA and includes species that occur across a wide moisture gradient. Data were compiled from published scientific papers, unpublished reports, plant fact sheets, existing trait databases, regional floras, and plant guides. Data for ordinal environmental tolerances were more readily available than were quantitative traits. More publicly available data are needed for traits of both common and rare southwestern U.S. plant species to facilitate comprehensive, trait-based research. The trait data set is free to use and can be downloaded from ScienceBase: https://www.sciencebase.gov/catalog/item/58af41dee4b01ccd54f9f2ff and https://dx.doi.org/10.5066/F7QV3JN1

  17. Changes in community-level riparian plant traits over inundation gradients, Colorado River, Grand Canyon

    Science.gov (United States)

    McCoy-Sulentic, Miles; Kolb, Thomas; Merritt, David; Palmquist, Emily C.; Ralston, Barbara E.; Sarr, Daniel; Shafroth, Patrick B.

    2017-01-01

    Comparisons of community-level functional traits across environmental gradients have potential for identifying links among plant characteristics, adaptations to stress and disturbance, and community assembly. We investigated community-level variation in specific leaf area (SLA), plant mature height, seed mass, stem specific gravity (SSG), relative cover of C4 species, and total plant cover over hydrologic zones and gradients in years 2013 and 2014 in the riparian plant community along the Colorado River in the Grand Canyon. Vegetation cover was lowest in the frequently inundated active channel zone, indicating constraints on plant establishment and production by flood disturbance and anaerobic stress. Changes in trait values over hydrologic zones and inundation gradients indicate that frequently inundated plots exhibit a community-level ruderal strategy with adaptation to submergence (high SLA and low SSG, height, seed mass, C4 relative cover), whereas less frequently inundated plots exhibit adaptation to drought and infrequent flood disturbance (low SLA and high SSG, height, seed mass, C4 relative cover). Variation in traits not associated with inundation suggests niche differentiation and multiple modes of community assembly. The results enhance understanding of future responses of riparian communities of the Grand Canyon to anticipated drying and changes in hydrologic regime.

  18. Energy development vs water quality in the Upper Colorado and Upper Missouri River Basins

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, A.B.; Klemetson, S.L.; Torpy, M.F.; McKee, M.

    1978-10-01

    This report examines the relationship between energy development and water quality in the Upper Colorado and Upper Missouri River Basins. The location and type of energy resources and present and possible future developments are identified relative to the water resource systems. Impacts from energy developments are discussed in terms of the various pollutants generated by energy extraction and processing activities, and the pollution transport mechanisms and pathways by which they can enter surface and groundwater. The report discusses the implications for energy development of the water quality aspects of legislative requirements and regulations. These include the Federal Water Pollution Control Act Amendments, the Safe Drinking Water Act, the Surface Mining Control and Reclamation Act, the Resource Conservation and Recovery Act, and the Toxic Substances Control Act. Many of the potential water pollution problems associated with energy development will occur through the transport of pollutants from air pollution and solid waste disposal. The consumptive use of all water withdrawn for energy processing as a pollution control measure raises three important issues--each of which represents a potential conflict between energy developers' compliance with the legislation and western water law: (1) junior rights and water transfer, (2) the beneficial use question, and (3) the reasonable use measure of certain water quality practices.

  19. Diets of insectivorous birds along the Colorado River in Grand Canyon, Arizona

    Science.gov (United States)

    Yard, H.K.; van Riper, Charles; Brown, B.T.; Kearsley, M.J.

    2004-01-01

    We examined diets of six insectivorous bird species (n = 202 individuals) from two vegetation zones along the Colorado River in Grand Canyon National Park, Arizona, 1994. All bird species consumed similar quantities of caterpillars and beetles, but use of other prey taxa varied. Non-native leafhoppers (Opsius stactagolus) specific to non-native tamarisk (Tamarix chinensis) substantially augmented Lucy's Warbler (Vermivora luciae) diets (49%), while ants comprised 82% of Yellow-breasted Chat (Icteria virens) diets. Yellow Warbler (Dendroica petechia) diets were composed of 45% aquatic midges. All bird species consumed the non-native leafhopper specific to tamarisk. Comparison of bird diets with availability of arthropod prey from aquatic and terrestrial origins showed terrestrial insects comprised 91% of all avian diets compared to 9% of prey from aquatic origin. Seasonal shifts in arthropod prey occurred in diets of three bird species, although no seasonal shifts were detected in arthropods sampled in vegetation indicating that at least three bird species were not selecting prey in proportion to its abundance. All bird species had higher prey overlap with arthropods collected in the native, mesquite-acacia vegetation zone which contained higher arthropod diversity and better prey items (i.e., Lepidoptera). Lucy's Warbler and Yellow Warbler consumed high proportions of prey items found in greatest abundance in the tamarisk-dominated vegetation zone that has been established since the construction of Glen Canyon Dam. These species appeared to exhibit ecological plasticity in response to an anthropogenic increase in prey resources.

  20. Concentration of contaminants in breeding bird eggs from the Colorado River Delta, Mexico.

    Science.gov (United States)

    García-Hernández, Jaqueline; Sapozhnikova, Yelena V; Schlenk, Daniel; Mason, Andrew Z; Hinojosa-Huerta, Osvel; Rivera-Díaz, Juan José; Ramos-Delgado, Norma Alicia; Sánchez-Bon, Gerardo

    2006-06-01

    Organic contaminants (organochlorine [OC], organophosphorus [OP] pesticides and polychlorinated biphenyls [PCBs]), and metals (As, Cd, Hg, Pb, and Se) are a concern to avian health in the Colorado River delta, Mexico. We determined concentrations of contaminants in eggs of three breeding species of birds from the delta (mourning doves [Zenaida macroura], burrowing owls [Athene cunicularia], and marsh wrens [Cistothorus palustris]). We collected 27 eggs of mourning doves, eight eggs of burrowing owls, and 18 eggs of marsh wrens for analyses. Polychlorinated biphenyls, OC, and OP pesticides were analyzed by gas chromatography equipped with an electron capture detector, and metals were analyzed by inductively coupled plasma mass spectrometry. The non-ortho PCB congeners (PCB 77 and 126) were found in mourning dove and burrowing owl eggs at concentrations in which hatchability can be affected. Mean selenium concentration found in marsh wren eggs (5.6 microg/g dry wt) exceeded the level of concern. Arsenic and Cd were found at higher than normal concentrations, Hg concentrations did not exceed the level of concern in any of the species, and Pb concentrations were higher in eggs of species subject to hunting. With the exception of lead, marsh wren eggs contained the highest metal concentrations.

  1. Environmental drivers of fish functional diversity and composition in the Lower Colorado River Basin

    Science.gov (United States)

    Pool, T.K.; Olden, J.D.; Whittier, Joanna B.; Paukert, C.P.

    2010-01-01

    Freshwater conservation efforts require an understanding of how natural and anthropogenic factors shape the present-day biogeography of native and non-native species. This knowledge need is especially acute for imperiled native fishes in the highly modified Lower Colorado River Basin (LCRB), USA. In the present study we employed both a taxonomic and functional approach to explore how natural and human-related environmental drivers shape landscape-scale patterns of fish community composition in the LCRB. Our results showed that hydrologic alteration, watershed land use, and regional climate explained 30.3% and 44.7% of the total variation in fish community taxonomic and functional composition, respectively. Watersheds with greater dam densities and upstream storage capacity supported higher non-native functional diversity, suggesting that dams have provided additional "niche opportunities" for non-native equilibrium life-history strategists by introducing new reservoir habitat and modifying downstream flow and thermal regimes. By contrast, watersheds characterized by greater upstream land protection, lower dam densities, and higher variation in spring and summer precipitation supported fish communities with a strong complement of native species (opportunistic-periodic strategists). In conclusion, our study highlights the utility of a life-history approach to better understand the patterns and processes by which fish communities vary along environmental gradients.

  2. Response of selenium concentrations in groundwater to seasonal canal leakage, lower Gunnison River Basin, Colorado, 2013

    Science.gov (United States)

    Linard, J.I.; McMahon, P.B.; Arnold, L.R.; Thomas, J.C.

    2016-05-23

    Selenium is a water-quality concern in the lower Gunnison River Basin because irrigation water interacting with seleniferous soils derived from the Mancos Shale Formation has mobilized selenium and increased its concentrations in surface water. Understanding the occurrence of elevated selenium concentrations in groundwater is necessary because groundwater discharge is an important source of selenium in surface water in the basin. In 2013, the U.S. Geological Survey, in cooperation with the Bureau of Reclamation and the Colorado Water Conservation Board, began a study to understand how changes in groundwater levels attributed to canal leakage affected the concentrations and speciation of dissolved selenium in groundwater. The purpose of this report is to characterize the groundwater adjacent to an unlined leaky canal. Two locations, near the East Canal (W-N1 and W-N2) and farther from the East Canal (W-M1 and W-M2), were selected for nested monitoring well installations. The pressure exerted by changes in canal stage was more readily transferred to the deep groundwater measured in the W-N1 near the canal than the shallow groundwater at the W-N2 well. No definitive relation could be made between canal water-level elevation and water-level elevations in monitoring wells farther from the canal (W-M1 and W-M2). 

  3. A tale of two rivers: channel adjustments to restorative floods in the Green River in Dinosaur N.M. as compared to those in the Colorado River in Grand Canyon N.P.

    Science.gov (United States)

    Alexander, J. S.; Schmidt, J. C.

    2007-12-01

    Sediment mass balance is a critical system attribute in assessing the potential for restoration of dam-impacted rivers. We compared channel response to large floods on the Green River in Lodore Canyon to similar changes measured along the Colorado River in part of Grand Canyon National Park, a reach with similar geomorphic organization, regulatory constraints, and habitat management goals. The post-dam sediment mass balance of the Green River is indeterminate or in surplus, but the mass balance of the Colorado River is in deficit. Analysis of repeat measurements at 36 cross sections along a 20 km reach of Lodore Canyon show that the sand storage condition in 2006 was no different than the condition observed in 1994, despite an increased frequency of high magnitude floods. Four high magnitude floods occurred in 1997, 1999, 2005, and 2006, but only one, the 1999 flow, triggered channel adjustments to the bed and banks that were significantly different than those of the post- dam 2-year return flood. This condition of relative equilibrium contrasts the sand storage condition of the Colorado River in Grand Canyon, where sand bar area and volume have declined despite specific dam releases intended to rebuild sand bars. The contrasting patterns of channel adjustment in these rivers indicate that the opportunities and cost of restoration are likely to differ in relation to the sediment supply available for channel restoration.

  4. Dating of river terraces along Lefthand Creek, western High Plains, Colorado, reveals punctuated incision

    Science.gov (United States)

    Foster, Melissa A.; Anderson, Robert S.; Gray, Harrison J.; Mahan, Shannon

    2017-01-01

    The response of erosional landscapes to Quaternary climate oscillations is recorded in fluvial terraces whose quantitative interpretation requires numerical ages. We investigate gravel-capped strath terraces along the western edge of Colorado's High Plains to constrain the incision history of this shale-dominated landscape. We use ¹⁰Be and ²⁶Al cosmogenic radionuclides (CRNs), optically stimulated luminescence (OSL), and thermally transferred OSL (TT-OSL) to date three strath terraces, all beveled in shale bedrock and then deposited upon by Lefthand Creek, which drains the crystalline core of the Front Range. Our study reveals: (i) a long history (hundreds of thousands of years) of fluvial occupation of the second highest terrace, T2 (Table Mountain), with fluvial abandonment at 92 ± 3 ka; (ii) a brief occupation of a narrow and spatially confined terrace, T3, at 98 ± 7 ka; and (iii) a 10–25 thousand year period of cutting and fluvial occupation of a lower terrace, T4, marked by the deposition of a lower alluvial unit between 59 and 68 ka, followed by deposition of an upper alluvial package at 40 ± 3 ka. In conjunction with other recent CRN studies of strath terraces along the Colorado Front Range (Riihimaki et al., 2006; Dühnforth et al., 2012), our data reveal that long periods of lateral planation and fluvial occupation of strath terraces, sometimes lasting several glacial-interglacial cycles, are punctuated by brief episodes of rapid vertical bedrock incision. These data call into question what a singular terrace age represents, as the strath may be cut at one time (its cutting-age) and the terrace surface may be abandoned at a much later time (its abandonment age), and challenge models of strath terraces that appeal to simple pacing by the glacial-interglacial cycles.

  5. Chronology of Miocene-Pliocene deposits at Split Mountain Gorge, Southern California: A record of regional tectonics and Colorado River evolution

    Science.gov (United States)

    Dorsey, R.J.; Fluette, A.; McDougall, K.; Housen, B.A.; Janecke, S.U.; Axen, G.J.; Shirvell, C.R.

    2007-01-01

    Late Miocene to early Pliocene deposit at Split Mountain Gorge, California, preserve a record of basinal response to changes in regional tectonics, paleogeography, and evolution of the Colorado River. The base of the Elephant Trees Formation, magnetostratigraphically dated as 8.1 ?? 0.4 Ma, provides the earliest well-dated record of extension in the southwestern Salton Trough. The oldest marine sediments are ca. 6.3 Ma. The nearly synchronous timing of marine incursion in the Salton Trough and northern Gulf of California region supports a model for localization of Pacific-North America plate motion in the Gulf ca. 6 Ma. The first appearance of Colorado River sand at the Miocene-Pliocene boundary (5.33 Ma) suggests rapid propagation of the river to the Salton Trough, and supports a lake-spillover hypothesis for initiation of the lower Colorado River. ?? 2007 Geological Society of America.

  6. Water-level changes in the High Plains aquifer, Republican River Basin in Colorado, Kansas, and Nebraska, 2002 to 2015

    Science.gov (United States)

    McGuire, V.L.

    2016-12-29

    The High Plains aquifer underlies 111.8 million acres (about 175,000 square miles) in parts of eight States—Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. More than 95 percent of the water withdrawn from the High Plains aquifer is used for irrigation. Water-level declines began in parts of the High Plains aquifer soon after the beginning of substantial irrigation with groundwater in the aquifer area (about 1950). The Republican River Basin is 15.9 million acres (about 25,000 square miles) and is located in northeast Colorado, northern Kansas, and southwest Nebraska. The Republican River Basin overlies the High Plains aquifer for 87 percent of the basin area. Water-level declines had begun in parts of the High Plains aquifer within the Republican River Basin by 1964. In 2002, management practices were enacted in the Middle Republican Natural Resources District in Nebraska to comply with the Republican River Compact Final Settlement. The U.S. Geological Survey, in cooperation with the Middle Republican Natural Resources District, completed a study of water-level changes in the High Plains aquifer within the Republican River Basin from 2002 to 2015 to enable the Middle Republican Natural Resources District to assess the effect of the management practices, which were specified by the Republican River Compact Final Settlement. Water-level changes determined from this study are presented in this report.Water-level changes from 2002 to 2015 in the High Plains aquifer within the Republican River Basin, by well, ranged from a rise of 9.4 feet to a decline of 43.2 feet. The area-weighted, average water-level change from 2002 to 2015 in this part of the aquifer was a decline of 4.5 feet.

  7. Changes in streamflow extremes in the Colorado River Basin and implications for the water-energy nexus

    Science.gov (United States)

    Solander, K.; Bennett, K. E.; Middleton, R. S.

    2016-12-01

    The global phenomenon of climate change-induced shifts in precipitation leading to "wet regions getting wetter" and "dry regions getting drier" has been widely studied. However, the propagation of the changes in atmospheric moisture conditions to the ground within stream channels is not a direct relationship due to a combination of temporal differences in these moisture shifts and how water interacts with various land surfaces. Precipitation and streamflow changes in the Colorado River Basin (CRB) are of particular interest due to its rapidly growing population, projected temperature increases that are expected to be higher than elsewhere in the contiguous United States, and subsequent climate-driven disturbances including drought, vegetation mortality, and wildfire, thereby making the region more vulnerable to shifts in hydrologic extremes. Here, we attempt to determine how streamflow extremes have changed in the CRB by using the Generalized Extreme Value (GEV) and Mann-Kendall trend analysis on historical observations and future simulations. We specifically evaluate these changes in the context of key high- and low-flow metrics including the maximum, 95th percentile, 5th percentile, minimum, center timing, and 7Q10 maximum and minimum flows using daily data at the monthly, seasonal, and annual timescales. By evaluating how the center timing and other streamflow statistics are changing at different elevations, this study also assesses the relative influence of changes in snowmelt versus overall precipitation on the associated shifts in extremes. Historical streamflow records were obtained from the United States Geological Survey (USGS) GAGES II dataset, while future records were derived using downscaled simulations from IPCC's CMIP5 Global Climate Model (GCM) database. Although preliminary results of the future simulations suggest that climate change will cause 7Q10 low flows to increase by 7% over the long-term, the combined impacts of climate and vegetation

  8. Long-term monitoring of sandbars on the Colorado River in Grand Canyon using remote sensing

    Science.gov (United States)

    Ross, Robert P.; Grams, Paul E.

    2015-01-01

    Closure of Glen Canyon Dam in 1963 dramatically changed discharge and sediment supply to the downstream Colorado River in Marble and Grand Canyons. Magnitudes of seasonal flow variation have been suppressed, while daily fluctuations have increased because of hydropower generation. Lake Powell, the upstream reservoir, traps all sediment, leaving the Paria and Little Colorado Rivers as the main suppliers of fine sediment to the system below Glen Canyon Dam. The reduction in sediment supply, along with changes in discharge, have resulted in finesediment deficit (Topping et al., 2000), leading to a decrease in the size and number of alluvial sandbars (Schmidt and Graf, 1990; Schmidt et al., 2004). However, the understanding of these important spatial and temporal changes in sandbars located along the banks of the river have been limited to infrequent measurements mostly made by direct visitation and topographic surveying (Hazel et al., 2010). Aerial photographs are the only data available from which it is possible to evaluate changes in alluvial deposits at a large number of sites and compare recent conditions with those that existed prior to the initiation of ground-based monitoring in the early 1990s. Previous studies have evaluated the effects of Glen Canyon Dam on sandbars by analysis of comprehensive maps of surficial geology that are based on seven sets of aerial imagery taken between 1935 and 1996 for selected reaches in the first 120 km downstream from Lees Ferry, Arizona (Figure 1). These studies showed that the area of exposed sand in eddy-deposition zones was less in the post-dam period than in the pre-dam period (Leschin and Schmidt, 1995; Schmidt et al., 1999b; Sondossi, 2001, Sondossi and Schmidt, 2001, Schmidt et al., 2004). In this study, we extend these analyses to encompass a 74-year period by including maps of sand deposits visible in aerial imagery taken in 2002, 2005, and 2009 for the same reaches that were mapped in the earlier studies. Results

  9. Abundance Trends and Status of the Little Colorado River Population of Humpback Chub: An Update Considering 1989-2006 Data

    Science.gov (United States)

    Coggins,, Lewis G.

    2008-01-01

    EXECUTIVE SUMMARY In 1967, the humpback chub (Gila cypha) (HBC) was added to the federal list of endangered species and is today protected under the Endangered Species Act of 1973. Only six populations of humpback chub are currently known to exist, five in the Colorado River Basin above Lees Ferry, Arizona, and one in Grand Canyon, Arizona. The majority of Grand Canyon humpback chub are found in the Little Colorado River (LCR)-the largest tributary to the Colorado River in Grand Canyon-and the Colorado River near its confluence with the Little Colorado River. Monitoring and research of the Grand Canyon humpback chub population is overseen by the U.S. Geological Survey's (USGS) Grand Canyon Monitoring and Research Center (GCMRC) under the auspices of the Glen Canyon Dam Adaptive Management Program (GCDAMP), a Federal initiative to protect and improve resources downstream of Glen Canyon Dam. This report provides updated information on the status and trends of the LCR population in light of new information and refined assessment methodology. An earlier assessment of the LCR population (Coggins and others, 2006a) used data collected during 1989?2002; the assessment provided here includes that data and additional data collected through 2006. Catch-rate indices, closed population mark-recapture model abundance estimates, results from the original age-structured mark recapture (ASMR) model (Coggins and others, 2006b), and a newly refined ASMR model are presented. This report also seeks to (1) formally evaluate alternative stock assessment models using Pearson residual analyses and information theoretic procedures, (2) use mark-recapture data to estimate the relationship between HBC age and length, (3) translate uncertainty in the assignment of individual fish age to resulting estimates of recruitment and abundance from the ASMR model, and (4) evaluate past and present stock assessments considering the available data sources and analyses, recognizing the limitations

  10. Predicting the likelihood of altered streamflows at ungauged rivers across the conterminous United States

    Science.gov (United States)

    Eng, Kenny; Carlisle, Daren M.; Wolock, David M.; Falcone, James A.

    2013-01-01

    An approach is presented in this study to aid water-resource managers in characterizing streamflow alteration at ungauged rivers. Such approaches can be used to take advantage of the substantial amounts of biological data collected at ungauged rivers to evaluate the potential ecological consequences of altered streamflows. National-scale random forest statistical models are developed to predict the likelihood that ungauged rivers have altered streamflows (relative to expected natural condition) for five hydrologic metrics (HMs) representing different aspects of the streamflow regime. The models use human disturbance variables, such as number of dams and road density, to predict the likelihood of streamflow alteration. For each HM, separate models are derived to predict the likelihood that the observed metric is greater than (‘inflated’) or less than (‘diminished’) natural conditions. The utility of these models is demonstrated by applying them to all river segments in the South Platte River in Colorado, USA, and for all 10-digit hydrologic units in the conterminous United States. In general, the models successfully predicted the likelihood of alteration to the five HMs at the national scale as well as in the South Platte River basin. However, the models predicting the likelihood of diminished HMs consistently outperformed models predicting inflated HMs, possibly because of fewer sites across the conterminous United States where HMs are inflated. The results of these analyses suggest that the primary predictors of altered streamflow regimes across the Nation are (i) the residence time of annual runoff held in storage in reservoirs, (ii) the degree of urbanization measured by road density and (iii) the extent of agricultural land cover in the river basin.

  11. Age, distribution, and formation of late cenozoic paleovalleys of the lower Colorado River and their relation to river aggradation and degradation

    Science.gov (United States)

    Howard, K.A.; Lundstrom, S.C.; Malmon, D.V.; Hook, S.J.

    2008-01-01

    Distinctive far-traveled fluvial sediment of the lower Colorado River fills 20 paleo-valleys now stranded by the river downstream of Grand Canyon as it crosses the Basin and Range Province. These sediments resulted from two or more aggradational epi sodes in Pliocene and Pleistocene times following initial incision during the early Pliocene. A review of the stratigraphic evidence of major swings in river elevation over the last 5 m.y. from alternating degradation and aggradation episodes establishes a framework for understanding the incision and filling of the paleovalleys. The paleo-valleys are found mostly along narrow bedrock canyon reaches of the river, where divides of bedrock or old deposits separate them from the modern river. The paleo-valleys are interpreted to have stemmed from periods of aggradation that filled and broadened the river valley, burying low uplands in the canyon reaches into which later channel positions were entrenched during subsequent degradation episodes. The aggradation-degradation cycles resulted in the stranding of incised river valleys that range in elevation from near the modern river to 350 m above it. ?? 2008 The Geological Society of America.

  12. Water-Quality Data for Selected National Park Units within the Southern Colorado Plateau Network, Arizona, Utah, Colorado, and New Mexico, Water Years 2005 and 2006

    Science.gov (United States)

    Macy, Jamie P.; Monroe, Stephen A.

    2006-01-01

    The National Park Service initiated a Level 1 Water-Quality Inventory program to provide water-quality data to park managers so informed natural resource management decisions could be made. Level 1 water-quality data were collected by the U.S. Geological Survey Arizona Water Science Center at 57 sites in 13 National Park units located in the Southern Colorado Plateau Inventory and Monitoring network in water years 2005 and 2006. These data describe the current water-quality at selected sites within the park units and provide information for monitoring future trends. Water samples were collected three times at each type of site including wells, springs, seeps, tinajas, rivers, a lake, and an irrigation ditch. Field measurements were taken at each site and they included pH, specific conductance, temperature, barometric pressure, dissolved oxygen, alkalinity, turbidity, and discharge rates where applicable. Water samples collected were sent to the U.S. Geological Survey National Water Quality Laboratory and analyzed for major ions, trace elements, and nutrients. The National Water Quality Laboratory also analyzed selected samples for mercury and petroleum hydrocarbons. Additional samples at selected sites were collected and analyzed for cyanide, radiochemistry, and suspended sediment by U.S. Geological Survey contract labs. Fecal-indicator bacteria (Escherichia coli) were sampled for at selected sites as another indicator of water quality. Quality control for this study was achieved through proper training of field personnel, use of standard U.S. Geological Survey field and laboratory protocols, collection of sample blanks and replicates, and a thorough review of the water-quality analyses. Measured field pH ranged from 6.0 to 8.8, within normal range for springs and rivers, at most sites. Concentrations of dissolved solids ranged from 48 to 8,680 mg/L and the majority of samples had concentrations of dissolved solids below 900 mg/L. Trace-element concentrations at

  13. Biomonitoring of Environmental Status and Trends (BEST) Program: Environmental contaminants, health indicators, and reproductive biomarkers in fish from the Colorado River basin

    Science.gov (United States)

    Hinck, Jo Ellen; Blazer, Vicki; Denslow, Nancy D.; Gross, Timothy S.; Echols, Kathy R.; Davis, Anne P.; May, Tom W.; Orazio, Carl E.; Coyle, James J.; Tillitt, Donald E.

    2006-01-01

    Seven fish species were collected from 14 sites on rivers in the Colorado River Basin (CDRB) from August to October 2003. Spatial trends in the concentrations of accumulative contaminants were documented and contaminant effects on the fish were assessed. Sites were located on the mainstem of the Colorado River and on the Yampa, Green, Gunnison, San Juan, and Gila Rivers. Common carp (Cyprinus carpio), black bass (Micropterus sp.), and channel catfish (Ictalurus punctatus) were the targeted species. Fish were field-examined for external and internal anomalies, selected organs were weighed to compute somatic indices, and tissue and fluid samples were preserved for fish health and reproductive biomarker analyses. Composite samples of whole fish, grouped by species and gender, from each site were analyzed for organochlorine and elemental contaminants using performance-based and instrumental methods. 2,3,7,8-tetrachlorodibenzo-p-dioxin-like activity (TCDD-EQ) was measured using the H4IIE rat hepatoma cell bioassay. Selenium (Se) and mercury (Hg) concentrations were elevated throughout the CDRB, and pesticides concentrations were greatest in fish from agricultural areas in the Lower Colorado River and Gila River. Selenium concentrations exceeded toxicity thresholds for fish (>1.0 ?g/g ww) at all sites except from the Gila River at Hayden, Arizona. Mercury concentrations were elevated (>0.1 ?g/g ww) in fish from the Yampa River at Lay, Colorado; the Green River at Ouray National Wildlife Refuge (NWR), Utah and San Rafael, Utah; the San Juan River at Hogback Diversion, New Mexico; and the Colorado River at Gold Bar Canyon, Utah, Needles, California, and Imperial Dam, Arizona. Concentrations of p,p'-DDE were relatively high in fish from Arlington, Arizona (>1.0 ?g/g ww) and Phoenix, Arizona (>0.5 ?g/g ww). Concentrations of other banned pesticides including toxaphene, total chlordanes, and dieldrin were also greatest at these two sites but did not exceed toxicity thresholds

  14. Adaptation Challenges in Complex River Basins: Lessons Learned and Unlearned for the Colorado

    Science.gov (United States)

    Pulwarty, R. S.

    2008-12-01

    Climate variations affect the function and operation of existing water infrastructure - including hydropower, structural flood defenses, drainage and irrigation systems - as well as water management practices in support of efficiency and environmental needs. Selected basins around the world, including the Colorado, show agreements in model projections of increasing aridity. Adverse effects of climate change on freshwater systems aggravate the impacts of other stresses, such as population growth, changing economic activity, land-use change and urbanization and most importantly upstream-downstream winners and losers. Thus current water management practices may not be robust enough to cope with the impacts of climate change on water supply reliability. In many locations, water management does not even satisfactorily cope with current climate variability, so that large flood and drought-related environmental and economic damages occur on seasonal to decadal timescales. The recently released IPCC Technical Paper notes that adaptation procedures and risk management practices that incorporate projected hydrological changes with related uncertainties are being developed in some countries and regions.In this presentation we will review the challenges and lessons provided in drought and water resources management and optimization in the context of climate variability and projected change in the Western U.S., the European Union (including the Iberian Peninsula), the Murray-Darling Basin, and elsewhere. Since the release of the IPCC report several of the authors (including the presenter) have held meetings on comparative assessments of adaptation and its challenges in interstate and international river basins. As a first step, improved incorporation of information about current climate variability into water-related management could assist adaptation to longer-term climate change impacts. Future adaptations include technical changes that improve water use efficiency, demand

  15. In-place oil shale resources in the saline-mineral and saline-leached intervals, Parachute Creek Member of the Green River Formation, Piceance Basin, Colorado

    Science.gov (United States)

    Birdwell, Justin E.; Mercier, Tracey J.; Johnson, Ronald C.; Brownfield, Michael E.; Dietrich, John D.

    2014-01-01

    A recent U.S. Geological Survey analysis of the Green River Formation of the Piceance Basin in western Colorado shows that about 920 and 352 billion barrels of oil are potentially recoverable from oil shale resources using oil-yield cutoffs of 15 and 25 gallons per ton (GPT), respectively. This represents most of the high-grade oil shale in the United States. Much of this rich oil shale is found in the dolomitic Parachute Creek Member of the Green River Formation and is associated with the saline minerals nahcolite and halite, or in the interval where these minerals have been leached by groundwater. The remaining high-grade resource is located primarily in the underlying illitic Garden Gulch Member of the Green River Formation. Of the 352 billion barrels of potentially recoverable oil resources in high-grade (≥25 GPT) oil shale, the relative proportions present in the illitic interval, non-saline R-2 zone, saline-mineral interval, leached interval (excluding leached Mahogany zone), and Mahogany zone were 3.1, 4.5, 36.6, 23.9, and 29.9 percent of the total, respectively. Only 2 percent of high-grade oil shale is present in marginal areas where saline minerals were never deposited.

  16. Climate change impacts on streamflow and subbasin-scale hydrology in the Upper Colorado River Basin.

    Directory of Open Access Journals (Sweden)

    Darren L Ficklin

    Full Text Available In the Upper Colorado River Basin (UCRB, the principal source of water in the southwestern U.S., demand exceeds supply in most years, and will likely continue to rise. While General Circulation Models (GCMs project surface temperature warming by 3.5 to 5.6°C for the area, precipitation projections are variable, with no wetter or drier consensus. We assess the impacts of projected 21(st century climatic changes on subbasins in the UCRB using the Soil and Water Assessment Tool, for all hydrologic components (snowmelt, evapotranspiration, surface runoff, subsurface runoff, and streamflow, and for 16 GCMs under the A2 emission scenario. Over the GCM ensemble, our simulations project median Spring streamflow declines of 36% by the end of the 21(st century, with increases more likely at higher elevations, and an overall range of -100 to +68%. Additionally, our results indicated Summer streamflow declines with median decreases of 46%, and an overall range of -100 to +22%. Analysis of hydrologic components indicates large spatial and temporal changes throughout the UCRB, with large snowmelt declines and temporal shifts in most hydrologic components. Warmer temperatures increase average annual evapotranspiration by ∼23%, with shifting seasonal soil moisture availability driving these increases in late Winter and early Spring. For the high-elevation water-generating regions, modest precipitation decreases result in an even greater water yield decrease with less available snowmelt. Precipitation increases with modest warming do not translate into the same magnitude of water-yield increases due to slight decreases in snowmelt and increases in evapotranspiration. For these basins, whether modest warming is associated with precipitation decreases or increases, continued rising temperatures may make drier futures. Subsequently, many subbasins are projected to turn from semi-arid to arid conditions by the 2080 s. In conclusion, water availability in the UCRB

  17. 2008 Weather and Aeolian Sand-Transport Data from the Colorado River Corridor, Grand Canyon, Arizona

    Science.gov (United States)

    Draut, Amy E.; Sondossi, Hoda A.; Hazel, Joseph E.; Andrews, Timothy; Fairley, Helen C.; Brown, Christopher R.; Vanaman, Karen M.

    2009-01-01

    This report presents measurements of weather parameters and aeolian (windblown) sand transport made in 2008 near selected archaeological sites in the Colorado River corridor through Grand Canyon, Ariz. The quantitative methods and data discussed here form a basis for monitoring ecosystem processes that affect archeological-site stability. Combined with forthcoming work to evaluate landscape evolution at nearby archaeological sites, these data can be used to document the relationship between physical processes, including weather and aeolian sand transport, and their effects on the physical integrity of archaeological sites. Data collected in 2008 reveal event- and seasonal-scale variations in rainfall, wind, temperature, humidity, and barometric pressure. Broad seasonal changes in aeolian sediment flux are also apparent at most study sites. The continuation of monitoring that began in 2007, and installation of equipment at several new sites in early 2008, allowed evaluation of the effects of the March 2008 high-flow experiment (HFE) on aeolian sand transport. At two of the nine sites studied, spring and summer winds reworked 2008 HFE sandbars to form new aeolian dunes, at which sand moved inland toward larger, well-established dune fields. At the other seven study sites, neither dune formation nor enhanced sand transport after the HFE were observed. At several of those sites, dominant wind directions in spring 2008 were not oriented such that much HFE sand would have moved inland; at other sites, lack of increased inland sand flux is attributable to lack of sandbar enlargement near the study sites or to inhibition of sand movement by vegetation or local topography.

  18. A sampling plan for riparian birds of the Lower Colorado River-Final Report

    Science.gov (United States)

    Bart, Jonathan; Dunn, Leah; Leist, Amy

    2010-01-01

    A sampling plan was designed for the Bureau of Reclamation for selected riparian birds occurring along the Colorado River from Lake Mead to the southerly International Boundary with Mexico. The goals of the sampling plan were to estimate long-term trends in abundance and investigate habitat relationships especially in new habitat being created by the Bureau of Reclamation. The initial objective was to design a plan for the Gila Woodpecker (Melanerpes uropygialis), Arizona Bell's Vireo (Vireo bellii arizonae), Sonoran Yellow Warbler (Dendroica petechia sonorana), Summer Tanager (Piranga rubra), Gilded Flicker (Colaptes chrysoides), and Vermilion Flycatcher (Pyrocephalus rubinus); however, too little data were obtained for the last two species. Recommendations were therefore based on results for the first four species. The study area was partitioned into plots of 7 to 23 hectares. Plot borders were drawn to place the best habitat for the focal species in the smallest number of plots so that survey efforts could be concentrated on these habitats. Double sampling was used in the survey. In this design, a large sample of plots is surveyed a single time, yielding estimates of unknown accuracy, and a subsample is surveyed intensively to obtain accurate estimates. The subsample is used to estimate detection ratios, which are then applied to the results from the extensive survey to obtain unbiased estimates of density and population size. These estimates are then used to estimate long-term trends in abundance. Four sampling plans for selecting plots were evaluated based on a simulation using data from the Breeding Bird Survey. The design with the highest power involved selecting new plots every year. Power with 80 plots surveyed per year was more than 80 percent for three of the four species. Results from the surveys were used to provide recommendations to the Bureau of Reclamation for their surveys of new habitat being created in the study area.

  19. Climate change impacts on streamflow and subbasin-scale hydrology in the Upper Colorado River Basin.

    Science.gov (United States)

    Ficklin, Darren L; Stewart, Iris T; Maurer, Edwin P

    2013-01-01

    In the Upper Colorado River Basin (UCRB), the principal source of water in the southwestern U.S., demand exceeds supply in most years, and will likely continue to rise. While General Circulation Models (GCMs) project surface temperature warming by 3.5 to 5.6°C for the area, precipitation projections are variable, with no wetter or drier consensus. We assess the impacts of projected 21(st) century climatic changes on subbasins in the UCRB using the Soil and Water Assessment Tool, for all hydrologic components (snowmelt, evapotranspiration, surface runoff, subsurface runoff, and streamflow), and for 16 GCMs under the A2 emission scenario. Over the GCM ensemble, our simulations project median Spring streamflow declines of 36% by the end of the 21(st) century, with increases more likely at higher elevations, and an overall range of -100 to +68%. Additionally, our results indicated Summer streamflow declines with median decreases of 46%, and an overall range of -100 to +22%. Analysis of hydrologic components indicates large spatial and temporal changes throughout the UCRB, with large snowmelt declines and temporal shifts in most hydrologic components. Warmer temperatures increase average annual evapotranspiration by ∼23%, with shifting seasonal soil moisture availability driving these increases in late Winter and early Spring. For the high-elevation water-generating regions, modest precipitation decreases result in an even greater water yield decrease with less available snowmelt. Precipitation increases with modest warming do not translate into the same magnitude of water-yield increases due to slight decreases in snowmelt and increases in evapotranspiration. For these basins, whether modest warming is associated with precipitation decreases or increases, continued rising temperatures may make drier futures. Subsequently, many subbasins are projected to turn from semi-arid to arid conditions by the 2080 s. In conclusion, water availability in the UCRB could

  20. Abiotic & biotic responses of the Colorado River to controlled floods at Glen Canyon Dam, Arizona, USA

    Science.gov (United States)

    Korman, Josh; Melis, Ted; Kennedy, Theodore A.

    2012-01-01

    Closure of Glen Canyon Dam reduced sand supply to the Colorado River in Grand Canyon National Park by about 94% while its operation has also eroded the park's sandbar habitats. Three controlled floods released from the dam since 1995 suggest that sandbars might be rebuilt and maintained, but only if repeated floods are timed to follow tributary sand deliveries below the dam. Monitoring data show that sandbars are dynamic and that their erosion after bar building is positively related with mean daily discharge and negatively related with tributary sand production after controlled floods. The March 2008 flood affected non-native rainbow trout abundance in the Lees Ferry tailwater, which supports a blue ribbon fishery. Downstream trout dispersal from the tailwater results in negative competitive interactions and predation on endangered humpback chub. Early survival rates of age-0 trout increased more than fourfold following the 2008 flood, and twofold in 2009, relative to prior years (2006-2007). Hatch-date analysis indicated that early survival rates were much higher for cohorts that emerged about 2 months after the 2008 flood relative to cohorts that emerged earlier that year. The 2009 survival data suggest that tailwater habitat improvements persisted for at least a year, but apparently decreased in 2010. Increased early survival rates for trout coincided with the increased availability of higher quality drifting food items after the 2008 flood owing to an increase in midges and black flies, preferred food items of rainbow trout. Repeated floods from the dam might sustainably rebuild and maintain sandbars if released when new tributary sand is available below the tailwater. Spring flooding might also sustain increased trout abundance and benefit the tailwater fishery, but also be a potential risk to humpback chub in Grand Canyon.

  1. Cross-section data and pressure transducer location of the South Platte River near Fort Morgan, Colorado, 2017

    Science.gov (United States)

    Kohn, Michael S.

    2017-01-01

    The USGS Colorado Water Science Center, in cooperation with the Colorado Water Conservation Board, collected hydraulic data for the South Platte River for areas adjacent to Fort Morgan, Colo., based on the USGS streamgage 06759500 South Platte River at Fort Morgan, CO. The hydraulic data include survey point data for 54 cross sections and 10 pressure transducers, which are used to record the river stage beginning at Morgan County Road 16 and extending downstream to Morgan County Road 20.5 near Fort Morgan, Colo. The cross-section and pressure transducer location data were collected using real-time kinematic Global Navigation Satellite Systems by USGS personnel from February 15, 2017, through April 18, 2017. These data can be used to develop inundation maps, which could be available to emergency personnel, public officials, and the general public using an online public mapping application at the USGS Flood Inundation Mapper, which contains flood inundation map libraries from throughout the country created by the USGS.

  2. A Probabilistic Assessment of Threats to Surface Water Resources in Watersheds of the Lower Colorado River Basin

    Science.gov (United States)

    Murphy, K. W.; Ellis, A. W.

    2012-12-01

    The Salt and Verde River watersheds in the Lower Colorado River Basin are a very important surface water resource in the Southwest United States. Their runoff is captured by a downstream reservoir system serving approximately 40% of the water demand and providing hydroelectric power to the Phoenix, Arizona area. Concerns have been expressed over the risks associated with their highly variable climate dependencies under the realization that the short, historical stream flow record was but one of many possible temporal and volumetric outcome sequences. A characterization of the possible range of flow deficits arising from natural variability beyond those evident in the instrumental record can facilitate sustainability planning as well as adaptation to future climate change scenarios. Methods were developed for this study to generate very long seasonal time series of net reservoir inflows by Monte Carlo simulations of the Salt and Verde watersheds which can be analyzed for detailed probabilistic insights. Other efforts to generate stochastic flow representations for impact assessments have been limited by normality distribution assumptions, inability to represent the covariance of flow contributions from multiple watersheds, complexities of different seasonal origins of precipitation and runoff dependencies, and constraints from spectral properties of the observational record. These difficulties were overcome in this study through stationarity assessments and development of joint probability distributions with highly skewed discrete density functions characteristic of the different watershed-season behaviors derived from a 123 year record. As well, methods of introducing season-to-season correlations owing to antecedent precipitation runoff efficiency enhancements have been incorporated. Representative 10,000 year time series have been stochastically generated which reflect a full range of temporal variability in flow volume distributions. Extreme value statistical

  3. Summary of biological and contaminant investigations related to stream water quality and environmental setting in the Upper Colorado River basin, 1938-95

    Science.gov (United States)

    Deacon, Jeffrey R.; Stephens, Verlin C.

    1996-01-01

    As part of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) program, an inventory of the biological and contaminant investigations for the Upper Colorado River Basin study unit was conducted. To enhance the sampling design for the biological component of the program, previous studies about the ecology of aquatic organisms and contaminants were compiled from computerized literature searches of biological data bases and by contacting other Federal, State, and local agencies. Biological and contaminant investigations that have been conducted throughout the basin since 1938 were categorized according to four general categories of biological investigations and two categories of contaminant investigations: algal communities, macroinvertebrate communities, fish communities, habitat characterization, contaminants in organism tissue, and contaminants in bed sediment. The studies were identified by their locations in two physiographic provinces, the Southern Rocky Mountains and the Colorado Plateau, and by the predominant land use in the area of the investigation. Studies on algal communities and contaminants in organism tissue and in bed sediment are limited throughout the basin. Studies on macroinvertebrate and fish communities and habitat characterization are the most abundant in the study unit. Natural and human factors can affect biological communities and their composition. Natural factors that affect background water-quality conditions are physiography, climate, geology, and soils. Algae, macroinvertebrates, and fish that are present in the Southern Rocky Mountains and the Colorado Plateau physiographic provinces vary with altitude and physical environment. Green algae and diatoms are predominant in the higher altitude streams, and blue-green, golden-brown, and green algae are predominant in the lower altitude streams. Caddisflies, mayflies, and stoneflies are the dominant macroinvertebrates in the higher altitudes, whereas aquatic worms, leeches

  4. Fragmentation and thermal risks from climate change interact to affect persistence of native trout in the Colorado River basin

    Science.gov (United States)

    Roberts, James J.; Fausch, Kurt D.; Peterson, Douglas P.; Hooten, Mevin B.

    2013-01-01

    Impending changes in climate will interact with other stressors to threaten aquatic ecosystems and their biota. Native Colorado River cutthroat trout (CRCT; Oncorhynchus clarkii pleuriticus) are now relegated to 309 isolated high-elevation (>1700 m) headwater stream fragments in the Upper Colorado River Basin, owing to past nonnative trout invasions and habitat loss. Predicted changes in climate (i.e., temperature and precipitation) and resulting changes in stochastic physical disturbances (i.e., wildfire, debris flow, and channel drying and freezing) could further threaten the remaining CRCT populations. We developed an empirical model to predict stream temperatures at the fragment scale from downscaled climate projections along with geomorphic and landscape variables. We coupled these spatially explicit predictions of stream temperature with a Bayesian Network (BN) model that integrates stochastic risks from fragmentation to project persistence of CRCT populations across the upper Colorado River basin to 2040 and 2080. Overall, none of the populations are at risk from acute mortality resulting from high temperatures during the warmest summer period. In contrast, only 37% of populations have a greater than or equal to 90% chance of persistence for 70 years (similar to the typical benchmark for conservation), primarily owing to fragmentation. Populations in short stream fragments risk of extirpation. Therefore, interactions of stochastic disturbances with fragmentation are projected to be greater threats than warming for CRCT populations. The reason for this paradox is that past nonnative trout invasions and habitat loss have restricted most CRCT populations to high-elevation stream fragments that are buffered from the potential consequences of warming, but at risk of extirpation from stochastic events. The greatest conservation need is for management to increase fragment lengths to forestall these risks. 

  5. Making climate change projections relevant to water management: opportunities and challenges in the Colorado River basin (Invited)

    Science.gov (United States)

    Vano, J. A.

    2013-12-01

    By 2007, motivated by the ongoing drought and release of new climate model projections associated with the IPCC AR4 report, multiple independent studies had made estimates of future Colorado River streamflow. Each study had a unique approach, and unique estimate for the magnitude for mid-21st century streamflow change ranging from declines of only 6% to declines of as much as 45%. The differences among studies provided for interesting scientific debates, but to many practitioners this appeared to be just a tangle of conflicting predictions, leading to the question 'why is there such a wide range of projections of impacts of future climate change on Colorado River streamflow, and how should this uncertainty be interpreted?' In response, a group of scientists from academic and federal agencies, brought together through a NOAA cross-RISA project, set forth to identify the major sources of disparities and provide actionable science and guidance for water managers and decision makers. Through this project, four major sources of disparities among modeling studies were identified that arise from both methodological and model differences. These differences, in order of importance, are: (1) the Global Climate Models (GCMs) and emission scenarios used; (2) the ability of land surface hydrology and atmospheric models to simulate properly the high elevation runoff source areas; (3) the sensitivities of land surface hydrology models to precipitation and temperature changes; and (4) the methods used to statistically downscale GCM scenarios. Additionally, reconstructions of pre-instrumental streamflows provided further insights about the greatest risk to Colorado River streamflow of a multi-decadal drought, like those observed in paleo reconstructions, exacerbated by a steady reduction in flows due to climate change. Within this talk I will provide an overview of these findings and insights into the opportunities and challenges encountered in the process of striving to make

  6. Fragmentation and thermal risks from climate change interact to affect persistence of native trout in the Colorado River basin.

    Science.gov (United States)

    Roberts, James J; Fausch, Kurt D; Peterson, Douglas P; Hooten, Mevin B

    2013-05-01

    Impending changes in climate will interact with other stressors to threaten aquatic ecosystems and their biota. Native Colorado River cutthroat trout (CRCT; Oncorhynchus clarkii pleuriticus) are now relegated to 309 isolated high-elevation (>1700 m) headwater stream fragments in the Upper Colorado River Basin, owing to past nonnative trout invasions and habitat loss. Predicted changes in climate (i.e., temperature and precipitation) and resulting changes in stochastic physical disturbances (i.e., wildfire, debris flow, and channel drying and freezing) could further threaten the remaining CRCT populations. We developed an empirical model to predict stream temperatures at the fragment scale from downscaled climate projections along with geomorphic and landscape variables. We coupled these spatially explicit predictions of stream temperature with a Bayesian Network (BN) model that integrates stochastic risks from fragmentation to project persistence of CRCT populations across the upper Colorado River basin to 2040 and 2080. Overall, none of the populations are at risk from acute mortality resulting from high temperatures during the warmest summer period. In contrast, only 37% of populations have a ≥90% chance of persistence for 70 years (similar to the typical benchmark for conservation), primarily owing to fragmentation. Populations in short stream fragments fragmentation are projected to be greater threats than warming for CRCT populations. The reason for this paradox is that past nonnative trout invasions and habitat loss have restricted most CRCT populations to high-elevation stream fragments that are buffered from the potential consequences of warming, but at risk of extirpation from stochastic events. The greatest conservation need is for management to increase fragment lengths to forestall these risks. © 2013 Blackwell Publishing Ltd.

  7. Spawning ecology of flannelmouth sucker, Catostomus lattipinnis (Catostomidae), in two small tributaries of the lower Colorado river

    Science.gov (United States)

    Weiss, S.J.; Otis, E.O.; Maughan, O.E.

    1998-01-01

    We report the first published accounts of spawning behavior and spawning site selection of the flannelmouth sucker in two small tributaries of the lower Colorado River in the Grand Canyon, Arizona. Spawning was observed on 20 March 1992 and from 28 March to 10 April 1993 in the Paria River, and from 16 to 19 March 1993 in Bright Angel Creek. Flannelmouth suckers exhibited promiscuous spawning behavior-individual females were typically paired with two or more males for a given event and sometimes changed partners between events. Multiple egg deposits by different females sometimes occurred at one spawning site. Flannelmouth sucker selected substrates from 16 to 32 mm diameter in both streams. Spawning occurred at depths of 10 to 25 cm in the Paria River and 19 to 41 cm in Bright Angel Creek. Mean column water velocities at spawning locations ranged from 0.15 to 1.0 m sec-1 in the Paria River and from 0.23 to 0.89 m sec-1 in Bright Angel Creek. Water temperatures recorded during spawning ranged from 9 to 18??C in the Paria River and 13 to 15??C in Bright Angel Creek. Spawning flannelmouth sucker ascended 9.8 km upstream in the Paria River and 1.25 km in Bright Angel Creek. Spawning females (410-580 mm) were significantly larger than spawning males (385-530 mm) in the Paria River. The mean size of spawning fish in the Paria River was significantly smaller than the entire stock, averaged throughout the study period (380-620 mm). However, fish spawning in 1992-1993 averaged 53 mm larger than fish spawning in the same reach of the Paria River in 1981, indicating a shift in the size structure of this stock.

  8. The influence of controlled floods on fine sediment storage in debris fan-affected canyons of the Colorado River basin

    Science.gov (United States)

    Mueller, Erich R.; Grams, Paul E.; Schmidt, John C.; Hazel, Joseph E.; Alexander, Jason S.; Kaplinski, Matt

    2014-01-01

    Prior to the construction of large dams on the Green and Colorado Rivers, annual floods aggraded sandbars in lateral flow-recirculation eddies with fine sediment scoured from the bed and delivered from upstream. Flows greater than normal dam operations may be used to mimic this process in an attempt to increase time-averaged sandbar size. These controlled floods may rebuild sandbars, but sediment deficit conditions downstream from the dams restrict the frequency that controlled floods produce beneficial results. Here, we integrate complimentary, long-term monitoring data sets from the Colorado River in Marble and Grand Canyons downstream from Glen Canyon dam and the Green River in the Canyon of Lodore downstream from Flaming Gorge dam. Since the mid-1990s, several controlled floods have occurred in these canyon rivers. These controlled floods scour fine sediment from the bed and build sandbars in eddies, thus increasing channel relief. These changes are short-lived, however, as interflood dam operations erode sandbars within several months to years. Controlled flood response and interflood changes in bed elevation are more variable in Marble Canyon and Grand Canyon, likely reflecting more variable fine sediment supply and stronger transience in channel bed sediment storage. Despite these differences, neither system shows a trend in fine-sediment storage during the period in which controlled floods were monitored. These results demonstrate that controlled floods build eddy sandbars and increase channel relief for short interflood periods, and this response may be typical in other dam-influenced canyon rivers. The degree to which these features persist depends on the frequency of controlled floods, but careful consideration of sediment supply is necessary to avoid increasing the long-term sediment deficit.

  9. The influence of controlled floods on fine sediment storage in debris fan-affected canyons of the Colorado River basin

    Science.gov (United States)

    Mueller, Erich R.; Grams, Paul E.; Schmidt, John C.; Hazel, Joseph E.; Alexander, Jason S.; Kaplinski, Matt

    2014-12-01

    Prior to the construction of large dams on the Green and Colorado Rivers, annual floods aggraded sandbars in lateral flow-recirculation eddies with fine sediment scoured from the bed and delivered from upstream. Flows greater than normal dam operations may be used to mimic this process in an attempt to increase time-averaged sandbar size. These controlled floods may rebuild sandbars, but sediment deficit conditions downstream from the dams restrict the frequency that controlled floods produce beneficial results. Here, we integrate complimentary, long-term monitoring data sets from the Colorado River in Marble and Grand Canyons downstream from Glen Canyon dam and the Green River in the Canyon of Lodore downstream from Flaming Gorge dam. Since the mid-1990s, several controlled floods have occurred in these canyon rivers. These controlled floods scour fine sediment from the bed and build sandbars in eddies, thus increasing channel relief. These changes are short-lived, however, as interflood dam operations erode sandbars within several months to years. Controlled flood response and interflood changes in bed elevation are more variable in Marble Canyon and Grand Canyon, likely reflecting more variable fine sediment supply and stronger transience in channel bed sediment storage. Despite these differences, neither system shows a trend in fine-sediment storage during the period in which controlled floods were monitored. These results demonstrate that controlled floods build eddy sandbars and increase channel relief for short interflood periods, and this response may be typical in other dam-influenced canyon rivers. The degree to which these features persist depends on the frequency of controlled floods, but careful consideration of sediment supply is necessary to avoid increasing the long-term sediment deficit.

  10. Rapid incision of the Colorado River in Glen Canyon - insights from channel profiles, local incision rates, and modeling of lithologic controls

    Science.gov (United States)

    Cook, K.L.; Whipple, K.X.; Heimsath, A.M.; Hanks, T.C.

    2009-01-01

    The Colorado River system in southern Utah and northern Arizona is continuing to adjust to the baselevel fall responsible for the carving of the Grand Canyon. Estimates of bedrock incision rates in this area vary widely, hinting at the transient state of the Colorado and its tributaries. In conjunction with these data, we use longitudinal profiles of the Colorado and tributaries between Marble Canyon and Cataract Canyon to investigate the incision history of the Colorado in this region. We find that almost all of the tributaries in this region steepen as they enter the Colorado River. The consistent presence of oversteepened reaches with similar elevation drops in the lower section of these channels, and their coincidence within a corridor of high local relief along the Colorado, suggest that the tributaries are steepening in response to an episode of increased incision rate on the mainstem. This analysis makes testable predictions about spatial variations in incision rates; these predictions are consistent with existing rate estimates and can be used to guide further studies. We also present cosmogenic nuclide data from the Henry Mountains of southern Utah. We measured in situ 10Be concentrations on four gravel-covered strath surfaces elevated from 1 m to 110 m above Trachyte Creek. The surfaces yield exposure ages that range from approximately 2??5 ka to 267 ka and suggest incision rates that vary between 350 and 600 m/my. These incision rates are similar to other rates determined within the high-relief corridor. Available data thus support the interpretation that tributaries of the Colorado River upstream of the Grand Canyon are responding to a recent pulse of rapid incision on the Colorado. Numerical modeling of detachment-limited bedrock incision suggests that this incision pulse is likely related to the upstream-dipping lithologic boundary at the northern edge of the Kaibab upwarp. ?? 2009 John Wiley & Sons, Ltd.

  11. Sedimentos arcillosos en un suelo del valle inferior del río Colorado (Argentina Clay sediments in a soil of the lower Colorado river valley (Argentina

    Directory of Open Access Journals (Sweden)

    Norman Peinemann

    2008-12-01

    Full Text Available Se describe la presencia de capas sedimentarias ricas en minerales de arcilla en un subsuelo del valle inferior del río Colorado por su importancia para el régimen hídrico de suelos bajo riego. Difractogramas de rayos X efectuados sobre la fracción arcilla fina de estos sedimentos revelaron que está compuesta por smectitas con muy buena cristalización. La caracterización fisicoquímica del perfil de suelo mostró que el fuerte incremento de minerales de arcilla en el subsuelo estuvo vinculado con un aumento de pH y PSI y en consecuencia una marcada disminución en la conductividad hidráulica, motivo por el cual la eventual presencia de estas capas sedimentarias debe ser muy tenida en cuenta en la programación de las prácticas de riego para evitar el posible deterioro de los suelos.The presence of sedimentary clay layers in subsoils of the lower Colorado river valley are described due to their impact on the water balance of soils under irrigation. X-ray difractograms of the fine clay fraction of these sediments show that they are composed of smectites with a very good crystallization. The physicochemical characterization of the soil profile indicates that the abrupt increase of clay minerals was associated with high pH and ESP values as well as a sharp decrease in hydraulic conductivity. Therefore, the presence of sedimentary clay layers in soils has to be considered when planning irrigation practices to avoid soil degradation.

  12. Geochemical and geostatistical evaluation, Arkansas Canyon Planning Unit, Fremont and Custer Counties, Colorado

    Science.gov (United States)

    Weiland, E.F.; Connors, R.A.; Robinson, M.L.; Lindemann, J.W.; Meyer, W.T.

    1982-01-01

    A mineral assessment of the Arkansas Canyon Planning Unit was undertaken by Barringer Resources Inc., under the terms of contract YA-553-CTO-100 with the Bureau of Land Management, Colorado State Office. The study was based on a geochemical-geostatistical survey in which 700 stream sediment samples were collected and analyzed for 25 elements. Geochemical results were interpreted by statistical processing which included factor, discriminant, multiple regression and characteristic analysis. The major deposit types evaluated were massive sulfide-base metal, sedimentary and magmatic uranium, thorium vein, magmatic segregation, and carbonatite related deposits. Results of the single element data and multivariate geostatistical analysis indicate that limited potential exists for base metal mineralization near the Horseshoe, El Plomo, and Green Mountain Mines. Thirty areas are considered to be anomalous with regard to one or more of the geochemical parameters evaluated during this study. The evaluation of carbonatite related mineralization was restricted due to the lack of geochemical data specific to this environment.

  13. Characterization of hydrodynamic and sediment conditions in the lower Yampa River at Deerlodge Park, east entrance to Dinosaur National Monument, northwest Colorado, 2011

    Science.gov (United States)

    Williams, Cory A.

    2013-01-01

    The Yampa River in northwestern Colorado is the largest, relatively unregulated river system in the upper Colorado River Basin. Water from the Yampa River Basin continues to be sought for a number of municipal, industrial, and energy uses. It is anticipated that future water development within the Yampa River Basin above the amount of water development identified under the Upper Colorado River Endangered Fish Recovery Implementation Program and the Programmatic Biological Opinion may require additional analysis in order to understand the effects on habitat and river function. Water development in the Yampa River Basin could alter the streamflow regime and, consequently, could lead to changes in the transport and storage of sediment in the Yampa River at Deerlodge Park. These changes could affect the physical form of the reach and may impact aquatic and riparian habitat in and downstream from Deerlodge Park. The U.S. Geological Survey, in cooperation with the Colorado Water Conservation Board, began a study in 2011 to characterize the current hydrodynamic and sediment-transport conditions for a 2-kilometer reach of the Yampa River in Deerlodge Park. Characterization of channel conditions in the Deerlodge Park reach was completed through topographic surveying, grain-size analysis of streambed sediment, and characterization of streamflow properties. This characterization provides (1) a basis for comparisons of current stream functions (channel geometry, sediment transport, and stream hydraulics) to future conditions and (2) a dataset that can be used to assess channel response to streamflow alteration scenarios indicated from computer modeling of streamflow and sediment-transport conditions.

  14. Characterization of hydrodynamic and sediment conditions in the lower Yampa River at Deerlodge Park, east entrance to Dinosaur National Monument, northwest Colorado, 2011

    Science.gov (United States)

    Williams, Cory A.

    2013-01-01

    The Yampa River in northwestern Colorado is the largest, relatively unregulated river system in the upper Colorado River Basin. Water from the Yampa River Basin continues to be sought for a number of municipal, industrial, and energy uses. It is anticipated that future water development within the Yampa River Basin above the amount of water development identified under the Upper Colorado River Endangered Fish Recovery Implementation Program and the Programmatic Biological Opinion may require additional analysis in order to understand the effects on habitat and river function. Water development in the Yampa River Basin could alter the streamflow regime and, consequently, could lead to changes in the transport and storage of sediment in the Yampa River at Deerlodge Park. These changes could affect the physical form of the reach and may impact aquatic and riparian habitat in and downstream from Deerlodge Park. The U.S. Geological Survey, in cooperation with the Colorado Water Conservation Board, began a study in 2011 to characterize the current hydrodynamic and sediment-transport conditions for a 2-kilometer reach of the Yampa River in Deerlodge Park. Characterization of channel conditions in the Deerlodge Park reach was completed through topographic surveying, grain-size analysis of streambed sediment, and characterization of streamflow properties. This characterization provides (1) a basis for comparisons of current stream functions (channel geometry, sediment transport, and stream hydraulics) to future conditions and (2) a dataset that can be used to assess channel response to streamflow alteration scenarios indicated from computer modeling of streamflow and sediment-transport conditions.

  15. Sediment connectivity at source-bordering aeolian dunefields along the Colorado River in the Grand Canyon, USA

    Science.gov (United States)

    Sankey, Joel; Kasprak, Alan; Caster, Joshua; East, Amy; Fairley, Helen

    2017-04-01

    Aeolian dunefields that are primarily built and maintained with river-derived sediment are found in many river valleys throughout the world and are impacted by changes in climate, land use, and river regulation. Quantifying the dynamic response of these aeolian dunefields to alterations in river flow is especially difficult given the highly correlated nature of the interacting geomorphic and sediment transport processes that drive their formation and maintenance. We characterize the effects of controlled river floods on changes in sediment connectivity at source-bordering aeolian dunefields in the Grand Canyon, USA. Controlled floods from the Glen Canyon Dam are used to build sandbars along the Colorado River in Grand Canyon which provide the main sediment source for aeolian dunefields. Aeolian dunefields are a primary resource of concern for land managers in the Grand Canyon because they often contain buried archaeological features. To characterize dunefield response to controlled floods, we use a novel, automated approach for the mechanistic segregation of geomorphic change to discern the geomorphic processes responsible for driving topographic change in very high resolution digital elevation models-of-difference (DODs) that span multiple, consecutive controlled river floods at source-bordering dunefields. We subsequently compare the results of mechanistic segregation with modelled estimates of aeolian dunefield evolution in order to understand how dunefields respond to contemporary, anthropogenically-driven variability in sediment supply and connectivity. These methods provide a rapid technique for sediment budgeting and enable the inference of spatial and temporal patterns in sediment flux between the fluvial and aeolian domains. We anticipate that this approach will be adaptable to other river valleys where the interactions of aeolian, fluvial, and hillslope processes drive sediment connectivity for the maintenance of source-bordering aeolian dunefields.

  16. Preliminary Assessment of Landslides Along the Florida River Downstream from Lemon Reservoir, La Plata County, Colorado

    Science.gov (United States)

    Schulz, William H.; Coe, Jeffrey A.; Ellis, William L.; Kibler, John D.

    2006-01-01

    Nearly two-dozen shallow landslides were active during spring 2005 on a hillside located along the east side of the Florida River about one kilometer downstream from Lemon Reservoir in La Plata County, southwestern Colorado. Landslides on the hillside directly threaten human safety, residential structures, a county roadway, utilities, and the Florida River, and indirectly threaten downstream areas and Lemon Dam. Most of the area where the landslides occurred was burned during the 2002 Missionary Ridge wildfire. We performed geologic mapping, subsurface exploration and sampling, radiocarbon dating, and shallow ground-water and ground-displacement monitoring to assess landslide activity. Active landslides during spring 2005 were as large as 35,000 m3 and confined to colluvium. Debris flows were mobilized from most of the landslides, were as large as 1,500 m3, and traveled as far as 250 m. Landslide activity was triggered by elevated ground-water pressures within the colluvium caused by infiltration of snowmelt. Landslide activity ceased as ground-water pressures dropped during the summer. Shallow landslides on the hillside appear to be much more likely following the Missionary Ridge fire because of the loss of tree root strength and evapotranspiration. We used monitoring data and observations to develop preliminary, approximate rainfall/snowmelt thresholds above which shallow landslide activity can be expected. Landslides triggered during spring 2005 occurred within a 1.97 x 107 m3 older landslide that extends, on average, about 40 m into bedrock. The south end of this older landslide appears to have experienced deep secondary landsliding. Radiocarbon dating of sediments at the head of the older landslide suggests that the landslide was active about 1,424-1,696 years ago. A relatively widespread wildfire may have preceded the older landslide, and the landslide may have occurred during a wetter time. The wetter climate and effects of the wildfire would likely have

  17. Bed-material entrainment potential, Roaring Fork River at Basalt, Colorado

    Science.gov (United States)

    Elliott, John G.

    2002-01-01

    The Roaring Fork River at Basalt, Colorado, has a frequently mobile streambed composed of gravel, cobbles, and boulders. Recent urban and highway development on the flood plain, earlier attempts to realign and confine the channel, and flow obstructions such as bridge openings and piers have altered the hydrology, hydraulics, sediment transport, and sediment deposition areas of the Roaring Fork. Entrainment and deposition of coarse sediment on the streambed and in large alluvial bars have reduced the flood-conveying capacity of the river. Previous engineering studies have identified flood-prone areas and hazards related to inundation and high streamflow velocity, but those studies have not evaluated the potential response of the channel to discharges that entrain the coarse streambed. This study builds upon the results of earlier flood studies and identifies some potential areas of concern associated with bed-material entrainment. Cross-section surveys and simulated water-surface elevations from a previously run HEC?RAS model were used to calculate the boundary shear stress on the mean streambed, in the thalweg, and on the tops of adjacent alluvial bars for four reference streamflows. Sediment-size characteristics were determined for surficial material on the streambed, on large alluvial bars, and on a streambank. The median particle size (d50) for the streambed samples was 165 millimeters and for the alluvial bars and bank samples was 107 millimeters. Shear stresses generated by the 10-, 50-, and 100-year floods, and by a more common flow that just inundated most of the alluvial bars in the study reach were calculated at 14 of the cross sections used in the Roaring Fork River HEC?RAS model. The Shields equation was used with a Shields parameter of 0.030 to estimate the critical shear stress for entrainment of the median sediment particle size on the mean streambed, in the thalweg, and on adjacent alluvial bar surfaces at the 14 cross sections. Sediment

  18. Potential depletion of surface water in the Colorado River and agricultural drains by groundwater pumping in the Parker-Palo Verde-Cibola area, Arizona and California

    Science.gov (United States)

    Leake, Stanley A.; Owen-Joyce, Sandra J.; Heilman, Julian A.

    2013-01-01

    Water use along the lower Colorado River is allocated as “consumptive use,” which is defined to be the amount of water diverted from the river minus the amount that returns to the river. Diversions of water from the river include surface water in canals and water removed from the river by pumping wells in the aquifer connected to the river. A complication in accounting for water pumped by wells occurs if the pumping depletes water in drains and reduces measured return flow in those drains. In that case, consumptive use of water pumped by the wells is accounted for in the reduction of measured return flow. A method is needed to understand where groundwater pumping will deplete water in the river and where it will deplete water in drains. To provide a basis for future accounting for pumped groundwater in the Parker-Palo Verde-Cibola area, a superposition model was constructed. The model consists of three layers of finite-difference cells that cover most of the aquifer in the study area. The model was run repeatedly with each run having a pumping well in a different model cell. The source of pumped water that is depletion of the river, expressed as a fraction of the pumping rate, was computed for all active cells in model layer 1, and maps were constructed to understand where groundwater pumping depletes the river and where it depletes drains. The model results indicate that if one or more drains exist between a pumping well location and the river, nearly all of the depletion will be from drains, and little or no depletion will come from the Colorado River. Results also show that if a well pumps on a side of the river with no drains in the immediate area, depletion will come from the Colorado River. Finally, if a well pumps between the river and drains that parallel the river, a fraction of the pumping will come from the river and the rest will come from the drains. Model results presented in this report may be considered in development or refinement of strategies

  19. Integrating active restoration with environmental flows to improve native riparian tree establishment in the Colorado River Delta

    Science.gov (United States)

    Schlatter, Karen; Grabau, Matthew R.; Shafroth, Patrick B.; Zamora-Arroyo, Francisco

    2017-01-01

    Drastic alterations to river hydrology, land use change, and the spread of the nonnative shrub, tamarisk (Tamarix spp.), have led to the degradation of riparian habitat in the Colorado River Delta in Mexico. Delivery of environmental flows to promote native cottonwood (Populus spp.) and willow (Salix spp.) recruitment in human-impacted riparian systems can be unsuccessful due to flow-magnitude constraints and altered abiotic–biotic feedbacks. In 2014, an experimental pulse flow of water was delivered to the Colorado River in Mexico as part of the U.S.-Mexico binational agreement, Minute 319. We conducted a field experiment to assess the effects of vegetation removal, seed augmentation, and environmental flows, separately and in combination, on germination and first-year seedling establishment of cottonwood, willow, and tamarisk at five replicate sites along 5 river km. The relatively low-magnitude flow deliveries did not substantively restore natural fluvial processes of erosion, sediment deposition, and vegetation scour, but did provide wetted surface soils, shallow groundwater, and low soil salinity. Cottonwood and willow only established in wetted, cleared treatments, and establishment was variable in these treatments due to variable site conditions and inundation duration and timing. Wetted soils, bare surface availability, soil salinity, and seed availability were significant factors contributing to successful cottonwood and willow germination, while soil salinity and texture affected seedling persistence over the growing season. Tamarisk germinated and persisted in a wider range of environmental conditions than cottonwood and willow, including in un-cleared treatment areas. Our results suggest that site management can increase cottonwood and willow recruitment success from low-magnitude environmental flow events, an approach that can be applied in other portions of the Delta and to other human-impacted riparian systems across the world with similar

  20. Streamflow and sediment-transport data, Colorado River and three tributaries in Grand Canyon, Arizona, 1983 and 1985-86

    Science.gov (United States)

    Garrett, W.B.; van de Vanter, E.K.; Graf, J.B.

    1993-01-01

    The U.S. Geological Survey collected streamflow and sediment-transport data at 5 streamflow-gaging stations on the Colorado River between Glen Canyon Dam and Lake Mead as a part of an interagency environmental study. The data were collected for about 6 mo in 1983 and about 4 mo in 1985-86; data also were collected at 3 sites on tributary streams in 1983. The data were used for development of unsteady flow-routing and sediment-transport models, sand-load rating curves, and evaluation of channel changes. For the 1983 sampling period, 1,076 composite cross-section suspended-sediment samples were analyzed; 809 of these samples were collected on the main stem of the Colorado River and 267 samples were from the tributaries. Bed-material samples were obtained at 1,988 verticals; 161 samples of material in transport near the bed (bedload) were collected to define the location of sand, gravel, and bed rock in the channel cross section; and 664 discharge measurements were made. For the 1985-86 sampling period, 765 composite cross-section suspended-sediment samples and 887 individual vertical samples from cross sections were analyzed. Bed-material samples were obtained at 531 verticals, 159 samples of bedload were collected, and 218 discharge measurements were made. All data are presented in tabular form. Some types of data also are presented in graphs to better show trends or variations. (USGS)

  1. Economic value of angling on the Colorado River at Lees Ferry: Using secondary data to estimate the influence of seasonality

    Science.gov (United States)

    Bair, Lucas S.; Rogowski, David L.; Neher, Chris

    2016-01-01

    Glen Canyon Dam (GCD) on the Colorado River in northern Arizona provides water storage, flood control, and power system benefits to approximately 40 million people who rely on water and energy resources in the Colorado River basin. Downstream resources (e.g., angling, whitewater floating) in Glen Canyon National Recreation Area (GCNRA) and Grand Canyon National Park are impacted by the operation of GCD. The GCD Adaptive Management Program was established in 1997 to monitor and research the effects of dam operations on the downstream environment. We utilized secondary survey data and an individual observation travel cost model to estimate the net economic benefit of angling in GCNRA for each season and each type of angler. As expected, the demand for angling decreased with increasing travel cost; the annual value of angling at Lees Ferry totaled US$2.7 million at 2014 visitation levels. Demand for angling was also affected by season, with per-trip values of $210 in the summer, $237 in the spring, $261 in the fall, and $399 in the winter. This information provides insight into the ways in which anglers are potentially impacted by seasonal GCD operations and adaptive management experiments aimed at improving downstream resource conditions.

  2. Evaluation of MODIS, Epan and DAYMET-derived Potential Evapotranspiration Products in the Upper Colorado River Basin

    Science.gov (United States)

    Hogue, T. S.; Barik, M.; Franz, K.; Kinoshita, A. M.

    2013-12-01

    Potential evapotranspiration (PET) is a key variable in hydrologic forecasting, drought analysis, ecological modeling, and irrigation demand. This presentation overviews an analysis of a Moderate Resolution Imaging Spectroradiometer (MODIS) based PET product for seven basins in the Upper Colorado River Basin. The MODIS-PET (daily, 250m) is evaluated against two distributed PET products, the Colorado Basin River Forecast Center's North American Land Data Assimilation System (NLDAS) synthetic pan data (Epan) (daily, 0.125°) and a Hargreaves PET derived from Numerical Terradynamic Simulation Group's DAYMET variables (daily, 1km). The three distributed PET products showed large seasonal and climate variability, with the MODIS-PET better representing spatial variability, especially with respect to elevation change in the tested basins. All PET products are also evaluated against three regional flux towers. The MODIS-PET and Epan better represent flux tower values, while the Daymet PET significantly underestimates the point-based PET. The MODIS-PET are calculated in near-real-time which we advocate will ultimately provide more reasonable representation of current climatological conditions and the ability for near real-time streamflow forecasting, drought monitoring and crop water demand.

  3. Civilization’s Drying Cradle: Water Politics in the Tigris-Euphrates River Basin

    Science.gov (United States)

    2012-03-22

    Stanford Law Review 19, no. 2 (January 1967): 368, in JSTOR (accessed March 4, 2012). 75Treaty between the United States of America and Mexico...and Environment Database , “Colorado River Water Dispute (Colorado Case),” http://www1.american.edu/TED/colorado.htm (accessed March 4, 2012). 78U.S

  4. Subsurface Nitrogen-Cycling Microbial Communities at Uranium Contaminated Sites in the Colorado River Basin

    Science.gov (United States)

    Cardarelli, E.; Bargar, J.; Williams, K. H.; Dam, W. L.; Francis, C.

    2015-12-01

    Throughout the Colorado River Basin (CRB), uranium (U) persists as a relic contaminant of former ore processing activities. Elevated solid-phase U levels exist in fine-grained, naturally-reduced zone (NRZ) sediments intermittently found within the subsurface floodplain alluvium of the following Department of Energy-Legacy Management sites: Rifle, CO; Naturita, CO; and Grand Junction, CO. Coupled with groundwater fluctuations that alter the subsurface redox conditions, previous evidence from Rifle, CO suggests this resupply of U may be controlled by microbially-produced nitrite and nitrate. Nitrification, the two-step process of archaeal and bacterial ammonia-oxidation followed by bacterial nitrite oxidation, generates nitrate under oxic conditions. Our hypothesis is that when elevated groundwater levels recede and the subsurface system becomes anoxic, the nitrate diffuses into the reduced interiors of the NRZ and stimulates denitrification, the stepwise anaerobic reduction of nitrate/nitrite to dinitrogen gas. Denitrification may then be coupled to the oxidation of sediment-bound U(IV) forming mobile U(VI), allowing it to resupply U into local groundwater supplies. A key step in substantiating this hypothesis is to demonstrate the presence of nitrogen-cycling organisms in U-contaminated, NRZ sediments from the upper CRB. Here we investigate how the diversity and abundances of nitrifying and denitrifying microbial populations change throughout the NRZs of the subsurface by using functional gene markers for ammonia-oxidation (amoA, encoding the α-subunit of ammonia monooxygenase) and denitrification (nirK, nirS, encoding nitrite reductase). Microbial diversity has been assessed via clone libraries, while abundances have been determined through quantitative polymerase chain reaction (qPCR), elucidating how relative numbers of nitrifiers (amoA) and denitrifiers (nirK, nirS) vary with depth, vary with location, and relate to uranium release within NRZs in sediment

  5. 2014 annual summary of the lower Gunnison River Basin Selenium Management Program water-quality monitoring, Colorado

    Science.gov (United States)

    Henneberg, Mark F.

    2016-08-10

    Dissolved-selenium loading analyses of data collected at 18 water-quality sites in the lower Gunnison River Basin in Colorado were completed through water year (WY) 2014. A WY is defined as October 1–September 30. Selenium is a trace element that bioaccumulates in aquatic food chains and can cause reproductive failure, deformities, and other harmful effects. This report presents information on the dissolved-selenium loads at 18 sites in the lower Gunnison River Basin for WYs 2011–2014. Annual dissolved-selenium loads were calculated at 5 sites with continuous U.S. Geological Survey (USGS) streamflow gages, whereas instantaneous dissolved-selenium loads were calculated for the remaining 13 sites using water-quality samples that had been collected periodically during WYs 2011–2014. Annual dissolved-selenium loads for WY 2014 ranged from 336 pounds (lb) at Uncompahgre River at Colona to 13,300 lb at Gunnison River near Grand Junction (Whitewater). Most sites in the basin had a median instantaneous dissolved-selenium load of less than 20.0 lb per day. In general, dissolved-selenium loads at Gunnison River main-stem sites showed an increase from upstream to downstream.The State of Colorado water-quality standard for dissolved selenium of 4.6 micrograms per liter (µg/L) was compared to the 85th percentiles for dissolved selenium at selected water-quality sites. Annual 85th percentiles for dissolved selenium were calculated for the five core USGS sites having streamflow gages using estimated dissolved-selenium concentrations from linear regression models. These annual 85th percentiles in WY 2014 ranged from 0.97 µg/L at Uncompahgre River at Colona to 16.7 µg/L at Uncompahgre River at Delta. Uncompahgre River at Delta and Whitewater were the only core sites where water samples exceeded the State of Colorado water-quality standard for dissolved selenium of 4.6 µg/L.Instantaneous 85th percentiles for dissolved selenium were calculated for sites with sufficient data

  6. Adaptive Management of Glen Canyon Dam: Two Decades of Large Scale Experimental Treatments Intended to Benefit Resources of the Colorado River in Grand Canyon, USA

    Science.gov (United States)

    Melis, Theodore

    2010-05-01

    Glen Canyon Dam was closed in 1963, primarily to store water for the rapidly developing southwestern United States. The dam's hydropower plant, with a generating capacity of up to 1,300 megawatts of electrical energy, was initially operated without daily peaking constraints from 1966 to 1990, resulting in daily tides on the Colorado River through Grand Canyon National Park of up to 4 meters. The influences of Glen Canyon Dam's peaking operations on downstream river resources through Grand Canyon have been intensively studied for nearly four decades. Following experimental reoperation of the dam in summer 1990, and five years of studies associated with a major environmental impact statement, the Glen Canyon Dam Adaptive Management Program was created in 1997, to evaluate whether a new experimental flow regime, combined with other non-flow treatments, can mitigate the detrimental effects of the former hydropeaking flow regime. Experimental flow treatments associated with the program over the last two decades have included the adoption of hourly and daily operating rules that now govern and constrain hydropeaking, periodic release of experimental controlled floods to rebuild sandbar habitats along shorelines and occasional steady flow tests intended to benefit the river's endangered humpback chub; one of the endemic fish of the Colorado River basin that experienced a population decline following dam closure. Other non-flow experimental treatments being evaluated by the program include removal of nonnative fish species, such as rainbow trout and other exotic fish, as well as translocation of humpback chub into other habitats below the dam where they might successfully spawn. Since 1995, three controlled flood experiments have been released from the dam to determine whether the remaining sand supplies that enter the Colorado River below the dam (about 6 to 16 percent of the predam sand supply) can be managed to create and maintain sandbar habitats used by humpback chub

  7. Ferricrete, manganocrete, and bog iron occurrences with selected sedge bogs and active iron bogs and springs in the upper Animas River watershed, San Juan County, Colorado

    Science.gov (United States)

    Yager, Douglas B.; Church, Stanley E.; Verplanck, Philip L.; Wirt, Laurie

    2003-01-01

    During 1996 to 2000, the Bureau of Land Management, National Park Service, Environmental Protection Agency, United States Department of Agriculture (USDA) Forest Service, and the U.S. Geological Survey (USGS) developed a coordinated strategy to (1) study the environmental effects of historical mining on Federal lands, and (2) remediate contaminated sites that have the greatest impact on water quality and ecosystem health. This dataset provides information that contributes to these overall objectives and is part of the USGS Abandoned Mine Lands Initiative. Data presented here represent ferricrete occurrences and selected iron bogs and springs in the upper Animas River watershed in San Juan County near Silverton, Colorado. Ferricretes (stratified iron and manganese oxyhydroxide-cemented sedimentary deposits) are one indicator of the geochemical baseline conditions as well as the effect that weathering of mineralized rocks had on water quality in the Animas River watershed prior to mining. Logs and wood fragments preserved in several ferricretes in the upper Animas River watershed, collected primarily along streams, yield radiocarbon ages of modern to 9,580 years B.P. (P.L. Verplanck, D.B. Yager, and S.E. Church, work in progress). The presence of ferricrete deposits along the current stream courses indicates that climate and physiography of the Animas River watershed have been relatively constant throughout the Holocene and that weathering processes have been ongoing for thousands of years prior to historical mining activities. Thus, by knowing where ferricrete is preserved in the watershed today, land-management agencies have an indication of (1) where metal precipitation from weathering of altered rocks has occurred in the past, and (2) where this process is ongoing and may confound remediation efforts. These data are included as two coverages-a ferricrete coverage and a bogs and springs coverage. The coverages are included in ArcInfo shapefile and Arc

  8. Water quality and aquatic toxicity data of 2002 spring thaw conditions in the upper Animas River watershed, Silverton, Colorado

    Science.gov (United States)

    Fey, D.L.; Wirt, L.; Besser, J.M.; Wright, W.G.

    2002-01-01

    This report presents hydrologic, water-quality, and biologic toxicity data collected during the annual spring thaw of 2002 in the upper Animas River watershed near Silverton, Colorado. The spring-thaw runoff is a concern because elevated concentrations of iron oxyhydroxides can contain sorbed trace metals that are potentially toxic to aquatic life. Water chemistry of streams draining the San Juan Mountains is affected by natural acid drainage and weathering of hydrothermal altered volcanic rocks and by more than a century of mining activities. The timing of the spring-thaw sampling effort was determined by reviewing historical climate and stream-flow hydrographs and current weather conditions. Twenty-one water-quality samples were collected between 11:00 AM March 27, 2002 and 6:00 PM March 30, 2002 to characterize water chemistry at the A-72 gage on the upper Animas River below Silverton. Analyses of unfiltered water at the A-72 gage showed a relation between turbidity and total-recoverable iron concentrations, and showed diurnal patterns. Copper and lead concentrations were related to iron concentrations, indicating that these elements are probably sorbed to colloidal iron material. Calcium, strontium, and sulfate concentrations showed overall decreasing trends due to dilution, but the loads of those constituents increased over the sampling period. Nine water-quality samples were collected near the confluence of Mineral Creek with the Animas River, the confluence of Cement Creek with the Animas River, and on the upper Animas River above the confluence with Cement Creek (three samples at each site). A total of six bulk water-toxicity samples were collected before, during, and after the spring thaw from the Animas River at the A-72 gage site. Toxicity tests conducted with the bulk water samples on amphipods did not show strong differences in toxicity among the three sampling periods; however, toxicity of river water to fathead minnows showed a decreasing trend

  9. Early Pliocene Hiatus in Sand Output by the Colorado River: Evidence From Marine Deposits in the Salton Trough, Southern California

    Science.gov (United States)

    Dorsey, R. J.; Bykerk-Kauffman, A.

    2015-12-01

    Early Pliocene deposits in the western Salton Trough preserve a high-fidelity record of sediment dispersal into the marine realm during initiation and early evolution of the Colorado River (CR). Grain-size fractionation, sediment routing, and transport dynamics of the early CR delta are recorded in sediments of the Fish Creek - Vallecito basin, which was located ~100 km south of Yuma along the transform plate boundary at 5 Ma. Early Pliocene delivery of CR sand to the basin took place in two distinct pulses: (1) deposition of sandy turbidites (Wind Caves Mbr of the Latrania Fm) in a restricted submarine canyon at Split Mt Gorge between ~5.3 and 5.1 Ma; and (2) progradation of a thick, widespread, coarsening-up deltaic sequence of marine mudstone, sandstone, and coquinas (Deguynos Fm) between ~4.8 and 4.2 Ma. Estimated flux of CR sediment during Wind Caves deposition was weak (~3-5 Mt/yr) compared to the long-term average (172±64 Mt/yr). The two pulses of CR sand input are separated by the Coyote Clay (CC, ~5.1-4.8 Ma), a regionally correlable, greenish-yellow-weathering marine claystone unit at the base of the Deguynos Fm. CC gradationally overlies Wind Caves turbidites in the area of the paleocanyon. In contrast, in the Coyote Mts 15-23 km to the south and SE, CC rests on coarse-grained locally-derived late Miocene sedimentary rocks, Alverson volcanics, and metamorphic basement rock along a regional unconformity. Identical claystone facies occur in the NW Indio Hills (restores to Yuma at the mouth of the CR at 5 Ma), and Sierra Cucapa in Mexico (~200 km south of Yuma at 5 Ma). Marine localities outside of the Wind Caves paleocanyon experienced slow to negligible sedimentation along a rugged rocky shoreline until abrupt arrival of CR-derived clay. CC accumulated in a sand-starved, pro-delta marine setting (Winker, 1987) over an inferred N-S distance of ~200 km. We therefore reject an alternate hypothesis that CC accumulated on the muddy slope of the prograding CR

  10. Experimental investigation of the effect of vegetation on soil, sediment erosion, and salt transport processes in the Upper Colorado River Basin Mancos Shale formation, Price, Utah, USA.

    Science.gov (United States)

    Because of concerns about salinity in the Colorado River, this study focused on saline and sodic soils associated with the Mancos Shale formation with the objective of investigating mechanisms driving sediment yield and salinity loads and the role of vegetation in altering soil chemistry in the Pric...

  11. Design and maintenance of a network for collecting high-resolution suspended-sediment data at remote locations on rivers, with examples from the Colorado River

    Science.gov (United States)

    Griffiths, Ronald E.; Topping, David J.; Andrews, Timothy; Bennett, Glenn E.; Sabol, Thomas A.; Melis, Theodore S.

    2012-01-01

    Management of sand and finer sediment in fluvial settings has become increasingly important for reasons ranging from endangered-species habitat to transport of sediment-associated contaminants. In all rivers, some fraction of the suspended load is transported as washload, and some as suspended bed material. Typically, the washload is composed of silt-and-clay-size sediment, and the suspended bed material is composed of sand-size sediment. In most rivers, as a result of changes in the upstream supply of silt and clay, large, systematic changes in the concentration of the washload occur over time, independent of changes in water discharge. Recent work has shown that large, systematic, discharge-independent changes in the concentration of the suspended bed material are also present in many rivers. In bedrock canyon rivers, such as the Colorado River in Grand Canyon National Park, changes in the upstream tributary supply of sand may cause large changes in the grain-size distribution of the bed sand, resulting in changes in both the concentration and grain-size distribution of the sand in suspension. Large discharge-independent changes in suspended-sand concentration coupled to discharge-independent changes in the grain-size distribution of the suspended sand are not unique to bedrock canyon rivers, but also occur in large alluvial rivers, such as the Mississippi River. These systematic changes in either suspended-silt-and-clay concentration or suspended-sand concentration may not be detectable by using conventional equal-discharge- or equal-width-increment measurements, which may be too infrequently collected relative to the time scale over which these changes in the sediment load are occurring. Furthermore, because large discharge-independent changes in both suspended-silt-and-clay and suspended-sand concentration are possible in many rivers, methods using water discharge as a proxy for suspended-sediment concentration (such as sediment rating curves) may not produce

  12. Unit stream power, minimum energy dissipation rate, and river engineering

    Institute of Scientific and Technical Information of China (English)

    Chih Ted Yang

    2010-01-01

    Unit stream power is the most important and dominant parameter for the determination of transport rate of sand,gravel, and hyper-concentrated sediment with wash load.Minimum energy dissipation rate theory, or its simplified minimum unit stream power and minimum stream power theories,can provide engineers the needed theoretical basis for river morphology and river engineering studies.The Generalized Sediment Transport model for Alluvial River Simulation computer mode series have been developed based on the above theories.The computer model series have been successfully applied in many countries.Examples will be used to illustrate the applications of the computer models to solving a wide range of river morphology and river engineering problems.

  13. The dynamic feedbacks between channel changes in the Colorado River Basin and the rapid invasion of Tamarisk

    Science.gov (United States)

    Manners, R.; Schmidt, J. C.

    2009-12-01

    The resiliency and sensitivity of western rivers to future climate change may be partly anticipated by the response of these rivers to past perturbations in stream flow and sediment supply. Predictions of earlier spring runoff and reduced peak flows of snowmelt-dominated streams mimic hydrologic changes caused by the closure and operation of large dams built within the past century. In the Colorado River Basin, channels have narrowed between 5 and 26% following large dam construction, but the correlation between flow reduction and channel narrowing is confounded by changes in bank strength caused by the rapid spread of the non-native riparian shrub, tamarisk (Tamarix spp.). Thus, predictions of future changes in channel form and analysis of past changes related to dams must distinguish between channel narrowing caused by direct changes in flow, and caused by the indirect effects wherein changes in flow regime allow expansion of non-native riparian vegetation that in turn leads to accelerated channel narrowing. Our research evaluates the geomorphic controls on tamarisk colonization, the role of tamarisk in accelerating the narrowing process, and the dynamic feedbacks between channel changes on western rivers and the invasion of non-native riparian species. The transformation of formerly active bars and channel margins into stable inset floodplain surfaces is the dominant process by which these channels have narrowed, as determined by detailed alluvial stratigraphy and dendrogeomorphology. We recreated the 3-dimensional bar surface present at the time of tamarisk establishment by excavating an extensive network of trenches. In doing this, we evaluated the hydraulic environment within which tamarisk established. We also characterized the hydrodynamic roughness of aging tamarisk stands from ground-based LiDAR scans to evaluate the role of tamarisk in the promotion of floodplain formation. Our study sites are representative of the predominant geomorphic organization of

  14. Prediction of water flows in Colorado River, Argentina Predicción de caudales en río Colorado, Argentina

    Directory of Open Access Journals (Sweden)

    Jorge O Pierini

    2012-11-01

    Full Text Available The identification of suitable models for predicting daily water flow is important for planning and management of water storage in reservoirs of Argentina. Long-term prediction of water flow is crucial for regulating reservoirs and hydroelectric plants, for assessing environmental protection and sustainable development, for guaranteeing correct operation of public water supply in cities like Catriel, 25 de Mayo, Colorado River and potentially also Bahía Blanca. In this paper, we analyze in Buta Ranquil flow time series upstream reservoir and hydroelectric plant in order to model and predict daily fluctuations. We compare results obtained by using a three-layer artificial neural network (ANN, and an autoregressive (AR model, using 18 years of data, of which the last 3 years are used for model validation by means of the root mean square error (RMSE, and measure of certainty (Skill. Our results point out to the better performance to predict daily water flow or refill them of the ANN model performance respect to the AR model.La identificación de modelos adecuados para predecir caudales diarios es importante para la planificación y la gestión de almacenamiento de agua en los embalses de la Argentina. La predicción a largo plazo del caudal es crucial para la regulación de los embalses y centrales hidroeléctricas, evaluar la protección del medio ambiente y el desarrollo sostenible, garantizar el correcto funcionamiento del abastecimiento público de agua en ciudades como Catriel, 25 de Mayo, río Colorado y también, eventualmente, en Bahía Blanca. En este trabajo, se analizan series de tiempo de caudales de agua, arriba del embalse y de la planta hidroeléctrica en Buta Ranquil, para modelar y predecir las fluctuaciones diarias. Se comparan los resultados obtenidos mediante el uso de una red neuronal artificial (ANN de tres capas y un modelo autoregresivo (AR, con 18 anos de datos, cuyos últimos 3 anos se utilizan para la validación del

  15. 76 FR 32237 - Florida Power Corporation, Crystal River Unit 3 Nuclear Generating Plant; Notice of Availability...

    Science.gov (United States)

    2011-06-03

    ... COMMISSION Florida Power Corporation, Crystal River Unit 3 Nuclear Generating Plant; Notice of Availability... Plants and Public Meetings for the License Renewal of Crystal River Unit 3 Nuclear Generating Plant... operation for Crystal River Unit 3 Nuclear Generating Plant. Crystal River Unit 3 Nuclear Generating Plant...

  16. Macroinvertebrate-based assessment of biological condition at selected sites in the Eagle River watershed, Colorado, 2000-07

    Science.gov (United States)

    Zuellig, Robert E.; Bruce, James F.; Healy, Brian D.; Williams, Cory A.

    2010-01-01

    The U.S. Geological Survey (USGS), in cooperation with the Colorado River Water Conservation District, Eagle County, Eagle River Water and Sanitation District, Upper Eagle Regional Water Authority, Colorado Department of Transportation, City of Aurora, Town of Eagle, Town of Gypsum, Town of Minturn, Town of Vail, Vail Resorts, Colorado Springs Utilities, Denver Water, and the U.S. Department of Agriculture Forest Service (FS), compiled macroinvertebrate (73 sites, 124 samples) data previously collected in the Eagle River watershed from selected USGS and FS studies, 2000-07. These data were analyzed to assess the biological condition (that is, biologically ?degraded? or ?good?) at selected sites in the Eagle River watershed and determine if site class (for example, urban or undeveloped) described biological condition. An independently developed predictive model was applied to calculate a site-specific measure of taxonomic completeness for macroinvertebrate communities, where taxonomic completeness was expressed as the ratio of observed (O) taxa to those expected (E) to occur at each site. Macroinvertebrate communities were considered degraded at sites were O/E values were less than 0.80, indicating that at least 20 percent of expected taxa were not observed. Sites were classified into one of four classes (undeveloped, adjacent road or highway or both, mixed, urban) using a combination of riparian land-cover characteristics, examination of topographic maps and aerial imagery, screening for exceedances in water-quality standards, and best professional judgment. Analysis of variance was used to determine if site class accounted for variability in mean macroinvertebrate O/E values. Finally, macroinvertebrate taxa observed more or less frequently than expected at urban sites were indentified. This study represents the first standardized assessment of biological condition of selected sites distributed across the Eagle River watershed. Of the 73 sites evaluated, just over

  17. Evaluating Landsat 8 evapotranspiration for water use mapping in the Colorado River Basin

    Science.gov (United States)

    Senay, Gabriel; Friedrichs, MacKenzie O.; Singh, Ramesh K.; Velpuri, Naga Manohar

    2016-01-01

    Evapotranspiration (ET) mapping at the Landsat spatial resolution (100 m) is essential to fully understand water use and water availability at the field scale. Water use estimates in the Colorado River Basin (CRB), which has diverse ecosystems and complex hydro-climatic regions, will be helpful to water planners and managers. Availability of Landsat 8 images, starting in 2013, provides the opportunity to map ET in the CRB to assess spatial distribution and patterns of water use. The Operational Simplified Surface Energy Balance (SSEBop) model was used with 528 Landsat 8 images to create seamless monthly and annual ET estimates at the inherent 100 m thermal band resolution. Annual ET values were summarized by land use/land cover classes. Croplands were the largest consumer of “blue” water while shrublands consumed the most “green” water. Validation using eddy covariance (EC) flux towers and water balance approaches showed good accuracy levels with R2 ranging from 0.74 to 0.95 and the Nash–Sutcliffe model efficiency coefficient ranging from 0.66 to 0.91. The root mean square error (and percent bias) ranged from 0.48 mm (13%) to 0.60 mm (22%) for daily (days of satellite overpass) ET and from 7.75 mm (2%) to 13.04 mm (35%) for monthly ET. The spatial and temporal distribution of ET indicates the utility of Landsat 8 for providing important information about ET dynamics across the landscape. Annual crop water use was estimated for five selected irrigation districts in the Lower CRB where annual ET per district ranged between 681 mm to 772 mm. Annual ET by crop type over the Maricopa Stanfield irrigation district ranged from a low of 384 mm for durum wheat to a high of 990 mm for alfalfa fields. A rainfall analysis over the five districts suggested that, on average, 69% of the annual ET was met by irrigation. Although the enhanced cloud-masking capability of Landsat 8 based on the cirrus band and utilization of the Fmask algorithm improved the

  18. Holocene alluvial stratigraphy and response to climate change in the Roaring River valley, Front Range, Colorado, USA

    Science.gov (United States)

    Madole, Richard F.

    2012-09-01

    Stratigraphic analyses and radiocarbon geochronology of alluvial deposits exposed along the Roaring River, Colorado, lead to three principal conclusions: (1) the opinion that stream channels in the higher parts of the Front Range are relics of the Pleistocene and nonalluvial under the present climate, as argued in a water-rights trial USA v. Colorado, is untenable, (2) beds of clast-supported gravel alternate in vertical succession with beds of fine-grained sediment (sand, mud, and peat) in response to centennial-scale changes in snowmelt-driven peak discharges, and (3) alluvial strata provide information about Holocene climate history that complements the history provided by cirque moraines, periglacial deposits, and paleontological data. Most alluvial strata are of late Holocene age and record, among other things, that: (1) the largest peak flows since the end of the Pleistocene occurred during the late Holocene; (2) the occurrence of a mid- to late Holocene interval (~ 2450-1630(?) cal yr BP) of warmer climate, which is not clearly identified in palynological records; and (3) the Little Ice Age climate seems to have had little impact on stream channels, except perhaps for minor (~ 1 m) incision.

  19. Holocene alluvial stratigraphy and response to climate change in the Roaring River valley, Front Range, Colorado, USA

    Science.gov (United States)

    Madole, Richard F.

    2012-01-01

    Stratigraphic analyses and radiocarbon geochronology of alluvial deposits exposed along the Roaring River, Colorado, lead to three principal conclusions: (1) the opinion that stream channels in the higher parts of the Front Range are relics of the Pleistocene and nonalluvial under the present climate, as argued in a water-rights trial USA v. Colorado, is untenable, (2) beds of clast-supported gravel alternate in vertical succession with beds of fine-grained sediment (sand, mud, and peat) in response to centennial-scale changes in snowmelt-driven peak discharges, and (3) alluvial strata provide information about Holocene climate history that complements the history provided by cirque moraines, periglacial deposits, and paleontological data. Most alluvial strata are of late Holocene age and record, among other things, that: (1) the largest peak flows since the end of the Pleistocene occurred during the late Holocene; (2) the occurrence of a mid- to late Holocene interval (~2450–1630(?) cal yr BP) of warmer climate, which is not clearly identified in palynological records; and (3) the Little Ice Age climate seems to have had little impact on stream channels, except perhaps for minor (~1 m) incision. Published

  20. Manual for estimating selected streamflow characteristics of natural-flow streams in the Colorado River basin in Utah

    Science.gov (United States)

    Christensen, R.C.; Johnson, E.B.; Plantz, G.G.

    1986-01-01

    Methods are presented for estimating 10 streamflow characteristics at three types of sites on natural flow streams in the Colorado River Basin in Utah. The streamflow characteristics include average discharge and annual maximum 1-, 7-, and 15-day mean discharges for recurrence intervals of 10, 50 and 100 years. At or near gaged sites, two methods weight gaging station data with regression equation values to estimate streamflow characteristics. At sites on ungaged streams, a method estimates streamflow characteristics using regression equations. The regression equations relate the streamflow characteristics to the following basin and climatic characteristics: contributing drainage area, mean basin elevation, mean annual precipitation, main channel slope, and forested area. Separate regression equations were developed for four hydrologically distinct regions in the study area. The standard error of estimate for the 10 streamflow characteristics ranges from 13% to 87%. Basin, climatic, and streamflow characteristics, available as of September 30, 1981, are presented for 135 gaging stations in Utah, Arizona, Colorado, and Wyoming. In addition, weighted estimates of the streamflow characteristics based on station data and the regression equation estimates are provided for most gaging stations. (Author 's abstract)

  1. Edaphic, salinity, and stand structural trends in chronosequences of native and non-native dominated riparian forests along the Colorado River, USA

    Science.gov (United States)

    Merritt, David M.; Shafroth, Patrick B.

    2012-01-01

    Tamarix spp. are introduced shrubs that have become among the most abundant woody plants growing along western North American rivers. We sought to empirically test the long-held belief that Tamarix actively displaces native species through elevating soil salinity via salt exudation. We measured chemical and physical attributes of soils (e.g., salinity, major cations and anions, texture), litter cover and depth, and stand structure along chronosequences dominated by Tamarix and those dominated by native riparian species (Populus or Salix) along the upper and lower Colorado River in Colorado and Arizona/California, USA. We tested four hypotheses: (1) the rate of salt accumulation in soils is faster in Tamarix-dominated stands than stands dominated by native species, (2) the concentration of salts in the soil is higher in mature stands dominated by Tamarix compared to native stands, (3) soil salinity is a function of Tamarix abundance, and (4) available nutrients are more concentrated in native-dominated stands compared to Tamarix-dominated stands. We found that salt concentration increases at a faster rate in Tamarix-dominated stands along the relatively free-flowing upper Colorado but not along the heavily-regulated lower Colorado. Concentrations of ions that are known to be preferentially exuded by Tamarix (e.g., B, Na, and Cl) were higher in Tamarix stands than in native stands. Soil salt concentrations in older Tamarix stands along the upper Colorado were sufficiently high to inhibit germination, establishment, or growth of some native species. On the lower Colorado, salinity was very high in all stands and is likely due to factors associated with floodplain development and the hydrologic effects of river regulation, such as reduced overbank flooding, evaporation of shallow ground water, higher salt concentrations in surface and ground water due to agricultural practices, and higher salt concentrations in fine-textured sediments derived from naturally saline

  2. Persistent organic pollutants associated to water fluxes and sedimentary processes in the Colorado River delta, Baja California, México.

    Science.gov (United States)

    Lugo-Ibarra, K C; Daesslé, L W; Macías-Zamora, J V; Ramírez-Álvarez, N

    2011-09-01

    Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were studied in sediment cores from two distinctive modern channels of the Colorado River (CR) delta. Their abundance and temporal changes are associated with flood-flows from the CR across the USA-Mexico border. The CR channel is directly exposed to river flood-flows while the Hardy River (HR) is a local channel derived mainly from agricultural runoff, geothermal effluents, and treated urban wastewater. Different headwater compositions and degrees of exposure to flood-flows appear to be the factors controlling the composition of persistent organic pollutants (POPs). Enrichment of OCPs (46 ng g(-1) dwt in HR and 4.37 ng g(-1) dwt in CR) occurred during or a few years after flooding. PCB-138 (4.2 ng g(-1)dwt) is enriched in HR suggesting its origin in dielectric oils from the geothermal power plant. PCB-28 (2.1 ng g(-1)dwt) in CR may be related with atmospheric input and/or re-deposition of upstream sediments. In surficial sediments (0-3 cm), only HR exceeds international sediment quality guidelines (4,4'-DDE=8.16 ng g(-1)dwt and ΣDDT=8.34 ng g(-1)dwt).

  3. Mountains, glaciers, and mines—The geological story of the Blue River valley, Colorado, and its surrounding mountains

    Science.gov (United States)

    Kellogg, Karl; Bryant, Bruce; Shroba, Ralph R.

    2016-02-10

    This report describes, in a nontechnical style, the geologic history and mining activity in the Blue River region of Colorado, which includes all of Summit County. The geologic story begins with the formation of ancient basement rocks, as old as about 1700 million years, and continues with the deposition of sedimentary rocks on a vast erosional surface beginning in the Cambrian Period (about 530 million years ago). This deposition was interrupted by uplift of the Ancestral Rocky Mountains during the late Paleozoic Era (about 300 million years ago). The present Rocky Mountains began to rise at the close of the Mesozoic Era (about 65 million years ago). A few tens of millions years ago, rifting began to form the Blue River valley; a major fault along the east side of the Gore Range dropped the east side down, forming the present valley. The valley once was filled by sediments and volcanic rocks that are now largely eroded. During the last few hundred-thousand years, at least two periods of glaciation sculpted the mountains bordering the valley and glaciers extended down the Blue River valley as far south as present Dillon Reservoir. Discovery of deposits of gold, silver, copper, and zinc in the late 1800s, particularly in the Breckenridge region, brought an influx of early settlers. The world-class molybdenum deposit at Climax, mined since the First World War, reopened in 2012 after a period of closure.

  4. Comparison of 2006-2007 Water Years and Historical Water-Quality Data, Upper Gunnison River Basin, Colorado

    Science.gov (United States)

    Solberg, P.A.; Moore, Bryan; Smits, Dennis

    2009-01-01

    Population growth and changes in land use have the potential to affect water quality and quantity in the upper Gunnison River basin. In 1995, the U.S. Geological Survey (USGS), in cooperation with the Bureau of Land Management, City of Gunnison, Colorado River Water Conservation District, Crested Butte South Metropolitan District, Gunnison County, Hinsdale County, Mount Crested Butte Water and Sanitation District, National Park Service, Town of Crested Butte, Upper Gunnison River Water Conservancy District, and Western State College established a water-quality monitoring program in the upper Gunnison River basin to characterize current water-quality conditions and to assess the effects of increased urban development and other land-use changes on water quality. The monitoring network has evolved into two groups of stations - stations that are considered long term and stations that are considered rotational. The long-term stations are monitored to assist in defining temporal changes in water quality (how conditions may change over time). The rotational stations are monitored to assist in the spatial definition of water-quality conditions (how conditions differ throughout the basin) and to address local and short-term concerns. Some stations in the rotational group were changed beginning in water year 2007. Annual summaries of the water-quality data from the monitoring network provide a point of reference for discussions regarding water-quality monitoring in the upper Gunnison River basin. This summary includes data collected during water years 2006 and 2007. The introduction provides a map of the sampling sites, definitions of terms, and a one-page summary of selected water-quality conditions at the network stations. The remainder of the summary is organized around the data collected at individual stations. Data collected during water years 2006 and 2007 are compared to historical data, State water-quality standards, and Federal water-quality guidelines. Data were

  5. Comparison of Water Years 2004-05 and Historical Water-Quality Data, Upper Gunnison River Basin, Colorado

    Science.gov (United States)

    Spahr, Norman E.; Hartle, David M.; Diaz, Paul

    2008-01-01

    Population growth and changes in land use have the potential to affect water quality and quantity in the upper Gunnison River Basin. In 1995, the U.S. Geological Survey (USGS), in cooperation with the Bureau of Land Management, City of Gunnison, Colorado River Water Conservation District, Crested Butte South Metropolitan District, Gunnison County, Hinsdale County, Mount Crested Butte Water and Sanitation District, National Park Service, Town of Crested Butte, Upper Gunnison River Water Conservancy District, and Western State College, established a water-quality monitoring program in the upper Gunnison River Basin to characterize current water-quality conditions and to assess the effects of increased urban development and other land-use changes on water quality. The monitoring network has evolved into two groups of stations - stations that are considered long term and stations that are considered rotational. The long-term stations are monitored to assist in defining temporal changes in water quality (how conditions may change over time). The rotational stations are monitored to assist in the spatial definition of water-quality conditions (how conditions differ throughout the basin) and to address local and short-term concerns. Some stations in the rotational group were changed beginning in water year 2007. Annual summaries of the water-quality data from the monitoring network provide a point of reference for discussions regarding water-quality monitoring in the upper Gunnison River Basin. This summary includes data collected during water years 2004 and 2005. The introduction provides a map of the sampling sites, definitions of terms, and a one-page summary of selected water-quality conditions at the network stations. The remainder of the summary is organized around the data collected at individual stations. Data collected during water years 2004 and 2005 are compared to historical data, State water-quality standards, and Federal water-quality guidelines. Data were

  6. Macroinvertebrate and algal community sample collection methods and data collected at selected sites in the Eagle River watershed, Colorado, 2000-07

    Science.gov (United States)

    Zuellig, Robert E.; Bruce, James F.

    2010-01-01

    State and local agencies are concerned about the effects of increasing urban development and human population growth on water quality and the biological condition of regional streams in the Eagle River watershed. In response to these needs, the U.S. Geological Survey initiated a study in cooperation with the Colorado River Water Conservation District, Eagle County, Eagle River Water and Sanitation District, Upper Eagle Regional Water Authority, Colorado Department of Transportation, City of Aurora, Town of Eagle, Town of Gypsum, Town of Minturn, Town of Vail, Vail Resorts, Colorado Springs Utilities, Denver Water, and the U.S. Department of Agriculture Forest Service. As part of this study, previously collected macroinvertebrate and algal data from the Eagle River watershed were compiled. This report includes macroinvertebrate data collected by the U.S. Geological Survey and(or) the U.S. Department of Agriculture Forest Service from 73 sites from 2000 to 2007 and algal data collected from up to 26 sites between 2000 and 2001 in the Eagle River watershed. Additionally, a brief description of the sample collection methods and data processing procedures are presented.

  7. Projected changes in seasonal drought and flood conditions in the Sierra Nevada and Colorado River basins (USA)

    Science.gov (United States)

    Stewart-Frey, Iris; Ficklin, Darren; Carrillo, Carlos; McIntosh, Russell

    2014-05-01

    The Sierra Nevada and Colorado River mountain ranges are the principal source of water for large urban and agricultural demands in the North American Southwest. In this region, GCM ensemble output suggests varying and modest precipitation changes, while air surface temperatures are expected to increase by several degrees by the end of the century. This study used the downscaled output of an ensemble of 16 GCMs and 2 emission scenarios to drive the SWAT watershed model, and to assess the impact of projected climatic changes on water availability and water quality through 2100. We then assess the changes in likelihood of occurrence of high (> 125%, > 150%) and low (< 75%, 150% of historic averages in high elevation regions and in main channels. The occurrence of extreme low flows are likely to significantly increase for the spring and summer seasons, with low flows of

  8. Derived, still living cockroach genus Cariblattoides (Blattida: Blattellidae) from the Eocene sediments of Green River in Colorado, USA

    Institute of Scientific and Technical Information of China (English)

    Peter Vr(s)ansk(y); Lubomir Vidli(c)ka; Fedor (C)iampor Jr; Finnegan Marsh

    2012-01-01

    Cariblattoides labandeirai sp.n.from the Eocene sediments of Green River in Colorado,USA bear only two plesiomorphies,but also several significant autapomorphies within the advanced and highly derived living cockroach genus.Thus,Cariblattoides with extant occurrence in the Caribbean and South America was historically common in the Nearctic,and represents important evidence for the occurrence of derived living genera of cockroaches ~50 Ma ago.Generally,the vast majority of living genera were absent during the Palaeocene,thus the diversification of most living cockroach lineages near the Palaeocene/Eocene boundary must have been extremely rapid.Females of living C.suave,the type species,have identical (sophisticated) coloration of pronotum,but the most related living taxa are C.piraiensis and C.fontesi from Brazil (supported by phylogenetical analysis).

  9. Evaluation of groundwater levels in the South Platte River alluvial aquifer, Colorado, 1953-2012, and design of initial well networks for monitoring groundwater levels

    Science.gov (United States)

    Wellman, Tristan

    2015-01-01

    The South Platte River and underlying alluvial aquifer form an important hydrologic resource in northeastern Colorado that provides water to population centers along the Front Range and to agricultural communities across the rural plains. Water is regulated based on seniority of water rights and delivered using a network of administration structures that includes ditches, reservoirs, wells, impacted river sections, and engineered recharge areas. A recent addendum to Colorado water law enacted during 2002-2003 curtailed pumping from thousands of wells that lacked authorized augmentation plans. The restrictions in pumping were hypothesized to increase water storage in the aquifer, causing groundwater to rise near the land surface at some locations. The U.S. Geological Survey (USGS), in cooperation with the Colorado Water Conservation Board and the Colorado Water Institute, completed an assessment of 60 years (yr) of historical groundwater-level records collected from 1953 to 2012 from 1,669 wells. Relations of "high" groundwater levels, defined as depth to water from 0 to 10 feet (ft) below land surface, were compared to precipitation, river discharge, and 36 geographic and administrative attributes to identify natural and human controls in areas with shallow groundwater.

  10. A Vegetation Database for the Colorado River Ecosystem from Glen Canyon Dam to the Western Boundary of Grand Canyon National Park, Arizona

    Science.gov (United States)

    Ralston, Barbara E.; Davis, Philip A.; Weber, Robert M.; Rundall, Jill M.

    2008-01-01

    A vegetation database of the riparian vegetation located within the Colorado River ecosystem (CRE), a subsection of the Colorado River between Glen Canyon Dam and the western boundary of Grand Canyon National Park, was constructed using four-band image mosaics acquired in May 2002. A digital line scanner was flown over the Colorado River corridor in Arizona by ISTAR Americas, using a Leica ADS-40 digital camera to acquire a digital surface model and four-band image mosaics (blue, green, red, and near-infrared) for vegetation mapping. The primary objective of this mapping project was to develop a digital inventory map of vegetation to enable patch- and landscape-scale change detection, and to establish randomized sampling points for ground surveys of terrestrial fauna (principally, but not exclusively, birds). The vegetation base map was constructed through a combination of ground surveys to identify vegetation classes, image processing, and automated supervised classification procedures. Analysis of the imagery and subsequent supervised classification involved multiple steps to evaluate band quality, band ratios, and vegetation texture and density. Identification of vegetation classes involved collection of cover data throughout the river corridor and subsequent analysis using two-way indicator species analysis (TWINSPAN). Vegetation was classified into six vegetation classes, following the National Vegetation Classification Standard, based on cover dominance. This analysis indicated that total area covered by all vegetation within the CRE was 3,346 ha. Considering the six vegetation classes, the sparse shrub (SS) class accounted for the greatest amount of vegetation (627 ha) followed by Pluchea (PLSE) and Tamarix (TARA) at 494 and 366 ha, respectively. The wetland (WTLD) and Prosopis-Acacia (PRGL) classes both had similar areal cover values (227 and 213 ha, respectively). Baccharis-Salix (BAXX) was the least represented at 94 ha. Accuracy assessment of the

  11. Analysis of Dissolved Selenium Loading for Selected Sites in the Lower Gunnison River Basin, Colorado, 1978-2005

    Science.gov (United States)

    Thomas, Judith C.; Leib, Kenneth J.; Mayo, John W.

    2008-01-01

    Elevated selenium concentrations in streams are a water-quality concern in western Colorado. The U.S. Geologic Survey, in cooperation with the Colorado Department of Public Health and Environment, summarized selenium loading in the Lower Gunnison River Basin to support the development of total maximum daily selenium loads at sites that represent the cumulative contribution to U.S. Environmental Protection Agency 303(d) list segments. Analysis of selenium loading included quantifying loads and determining the amount of load that would need to be reduced to bring the site into compliance, referred to as 'the load reduction,' with the State chronic aquatic-life standard for dissolved selenium [85th percentile selenium concentration not to exceed 4.6 ?g/L (micrograms per liter)], referred to as 'the water-quality standard.' Streamflow and selenium concentration data for 54 historical water-quality/water-quantity monitoring sites were compiled from U.S. Geological Survey and Colorado Department of Public Health and Environment data sources. Three methods were used for analysis of selenium concentration data to address the variable data density among sites. Mean annual selenium loads were determined for only 10 of the 54 sites due to data availability limitations. Twenty-two sites had 85th percentile selenium concentrations that exceeded the water-quality standard, 3 sites had 85th percentile selenium concentrations less than the State standard, and 29 sites could not be evaluated with respect to 85th percentile selenium concentration (sample count less than 5). To bring selenium concentrations into compliance with the water-quality standard, more than 80 percent of the mean annual selenium load would need to be reduced at Red Rock Canyon, Dry Cedar Creek, Cedar Creek, Loutzenhizer Arroyo, Sunflower Drain, and Whitewater Creek. More than 50 percent of the mean annual load would need to be reduced at Dry Creek to bring the site into compliance with the water

  12. The implications of climate change scenario selection for future streamflow projection in the Upper Colorado River Basin

    Directory of Open Access Journals (Sweden)

    B. L. Harding

    2012-11-01

    Full Text Available The impact of projected 21st century climate conditions on streamflow in the Upper Colorado River Basin was estimated using a multi-model ensemble approach wherein the downscaled outputs of 112 future climate projections from 16 global climate models (GCMs were used to drive a macroscale hydrology model. By the middle of the century, the impacts on streamflow range, over the entire ensemble, from a decrease of approximately 30% to an increase of approximately the same magnitude. Although prior studies and associated media coverage have focused heavily on the likelihood of a drier future for the Colorado River Basin, approximately 25 to 35% of the ensemble of runs, by 2099 and 2039, respectively, result in no change or increases in streamflow. The broad range of projected impacts is primarily the result of uncertainty in projections of future precipitation, and a relatively small part of the variability of precipitation across the projections can be attributed to the effect of emissions pathways. The simulated evolution of future temperature is strongly influenced by emissions, but temperature has a smaller influence than precipitation on flow. Period change statistics (i.e., the change in flow from one 30-yr period to another vary as much within a model ensemble as between models and emissions pathways. Even by the end of the current century, the variability across the projections is much greater than changes in the ensemble mean. The relatively large ensemble analysis described herein provides perspective on earlier studies that have used fewer scenarios, and suggests that impact analyses relying on one or a few climate scenarios are unacceptably influenced by the choice of projections.

  13. The implications of climate change scenario selection for future streamflow projection in the Upper Colorado River Basin

    Directory of Open Access Journals (Sweden)

    B. L. Harding

    2012-01-01

    Full Text Available The impact of projected 21st century climate conditions on streamflow in the Upper Colorado River Basin was estimated using a multi-model ensemble approach wherein the downscaled outputs of 112 future climate scenarios from 16 global climate models (GCMs were used to drive a macroscale hydrology model. By the middle of the century, the impacts on streamflow range, over the entire ensemble, from a decrease of approximately 30% to an increase of approximately the same magnitude. Although prior studies and associated media coverage have focused heavily on the likelihood of a drier future for the Colorado River Basin, approximately one-third of the ensemble of runs result in little change or increases in streamflow. The broad range of projected impacts is primarily the result of uncertainty in projections of future precipitation, and a relatively small part of the variability of precipitation across the projections can be attributed to the effect of emissions scenarios. The simulated evolution of future temperature is strongly influenced by emissions, but temperature has a smaller influence than precipitation on flow. Period change statistics (i.e., the change in flow from one 30-yr period to another vary as much within a model ensemble as between models and emissions scenarios. Even over the course of the current century, the variability across the projections is much greater than the trend in the ensemble mean. The relatively large ensemble analysis described herein provides perspective on earlier studies that have used fewer scenarios, and suggests that impact analyses relying on one or a few scenarios, as is still common in dynamical downscaling assessments, are unacceptably influenced by choice of projections.

  14. Development and assessment of a landscape-scale ecological threat index for the Lower Colorado River Basin

    Science.gov (United States)

    Paukert, Craig P.; Pitts, K.L.; Whittier, Joanna B.; Olden, Julian D.

    2011-01-01

    Anthropogenic disturbances impact freshwater biota but are rarely incorporated into conservation planning due to the difficulties in quantifying threats. There is currently no widely accepted method to quantify disturbances, and determining how to measure threats to upstream catchments using disturbance metrics can be time consuming and subjective. We compared four watershed-scale ecological threat indices for the Lower Colorado River Basin (LCRB) using landscape-level threats of land use (e.g., agricultural and urban lands), waterway development and diversions (e.g., number of canals, dams), and human development (e.g., road and railroads density, pollution sites). The LCRB is an ideal region to assess ecological threat indices because of the increasing need for conservation to ensure the persistence of native fishes in highly altered habitat. Each threat was measured for severity (i.e., level of influence on the upstream watershed) and frequency throughout each watershed; both severity and frequency were measured using two different methods. Severity values were based either on peer-reviewed literature and weighted in accordance to their published ecological impact, or assumed equal severity across stressors. Threat frequency was calculated according to either the presence/absence of each stressor, or on the relative density of each stressor in the watershed. Each measure of severity was combined with a measure of frequency, creating four ecological threat indices, and transformed to a 0–100 scale. Threat indices were highly correlated (slopes of 0.94–1.63; R2 of 0.82–0.98), and were highest for watersheds close to urban centers, including Phoenix, Tucson, and Flagstaff, Arizona, and Las Vegas, Nevada. Road crossings and density appeared to be the most influential stressors in the index, but the removal of any individual stressor only changed the index by planning for the Lower Colorado River Basin.

  15. Atmospheric Dust in the Upper Colorado River Basin: Integrated Analysis of Digital Imagery, Total Suspended Particulate, and Meteorological Data

    Science.gov (United States)

    Urban, F. E.; Reynolds, R. L.; Neff, J. C.; Fernandez, D. P.; Reheis, M. C.; Goldstein, H.; Grote, E.; Landry, C.

    2012-12-01

    Improved measurement and observation of dust emission and deposition in the American west would advance understanding of (1) landscape conditions that promote or suppress dust emission, (2) dynamics of dryland and montane ecosystems, (3) premature melting of snow cover that provides critical water supplies, and (4) possible effects of dust on human health. Such understanding can be applied to issues of land management, water-resource management, as well as the safety and well-being of urban and rural inhabitants. We have recently expanded the scope of particulate measurement in the Upper Colorado River basin through the establishment of total-suspended-particulate (TSP) measurement stations located in Utah and Colorado with bi-weekly data (filter) collection, along with protocols for characterizing dust-on-snow (DOS) layers in Colorado mountains. A sub-network of high-resolution digital cameras has been co-located with several of the TSP stations, as well as at other strategic locations. These real-time regional dust-event detection cameras are internet-based and collect digital imagery every 6-15 minutes. Measurements of meteorological conditions to support these collections and observations are provided partly by CLIM-MET stations, four of which were deployed in 1998 in the Canyonlands (Utah) region. These stations provide continuous, near real-time records of the complex interaction of wind, precipitation, vegetation, as well as dust emission and deposition, in different land-use settings. The complementary datasets of dust measurement and observation enable tracking of individual regional dust events. As an example, the first DOS event of water year 2012 (Nov 5, 2011), as documented at Senator Beck Basin, near Silverton, Colorado, was also recorded by the camera at Island-in-the-Sky (200 km to the northwest), as well as in aeolian activity and wind data from the Dugout Ranch CLIM-MET station (170 km to the west-northwest). At these sites, strong winds and the

  16. Preliminary project proposal : White Ranch Units, Alamosa/Monte Vista National Wildlife Refuge, Colorado

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Proposal for the U.S. Fish and Wildlife Service and the Colorado Division of Wildlife to purchase the White Ranch property in Saguache County as partial fulfillment...

  17. Effects of three high-flow experiments on the Colorado River ecosystem downstream from Glen Canyon Dam, Arizona

    Science.gov (United States)

    Melis, Theodore S.

    2011-01-01

    Three high-flow experiments (HFEs) were conducted by the U.S. Department of the Interior at Glen Canyon Dam, Arizona, in March 1996, November 2004, and March 2008. These experiments, also known as artificial or controlled floods, were large-volume, scheduled releases of water from Glen Canyon Dam that were designed to mimic some aspects of pre-dam Colorado River seasonal flooding. The goal of these experiments was to determine whether high flows could be used to benefit important physical and biological resources in Glen Canyon National Recreation Area and Grand Canyon National Park that had been affected by the operation of Glen Canyon Dam. Efforts such as HFEs that seek to maintain and restore downstream resources are undertaken by the U.S. Department of the Interior under the auspices of the Grand Canyon Protection Act of 1992 (GCPA; title XVIII, secs. 1801-1809, of Public Law 102-575). Scientists conducted a wide range of monitoring and research activities before, during, and after the experiments. Initially, research efforts focused on whether HFEs could be used to rebuild and maintain Grand Canyon sandbars, which provide camping beaches for hikers and whitewater rafters, create habitats potentially used by native fish and other wildlife, and are the source of windborne sand that may help to protect some archaeological resources from weathering and erosion. As scientists gained a better understanding of how HFEs affect the physical environment, research efforts expanded to include additional investigations about the effects of HFEs on biological resources, such as native fishes, nonnative sports fishes, riverside vegetation, and the aquatic food web. The chapters that follow summarize and synthesize for decisionmakers and the public what has been learned about HFEs to provide a framework for implementing similar future experiments. This report is a product of the Glen Canyon Dam Adaptive Management Program (GCDAMP), a Federal initiative authorized to ensure

  18. Variability of low flow magnitudes in the Upper Colorado River Basin: identifying trends and relative role of large-scale climate dynamics

    Directory of Open Access Journals (Sweden)

    M. Pournasiri Poshtiri

    2014-07-01

    Full Text Available Low flow magnitude in a head water basin is important for planners because minimum available amount of water in a given time period often leads to concerns regarding serious repercussions, in both up and downstream regions. This is a common scenario in arid region like Colorado River basin located in the southwestern US. Low flow variability in Colorado River is due to complex interactions between several natural and anthropogenic factors; but we aim to identify the relative role of climate on varying low flow magnitudes at different spatial locations. The research questions we aim to answer are: Is there a systematic variability in water availability during the driest time of a year or season? How does that vary across locations and is there a link between large-scale climate and low flow variations? Towards that aim we select 17 stream gauge locations, which are identified as "undisturbed" meaning that these stations represent near-natural river flow regimes in the headwater region of Colorado River, which provides a useful resource for assessment of climate and hydrology associations without the confounding factor of major direct (e.g. water abstraction or indirect (e.g. land-use change human modification of flows. A detailed diagnostic analysis gives us fair understanding on the variability of low flow magnitude that is explained by climate. We also present spatial heterogeneity of hydro-climatological linkages that is important for suitable adaptive management measures.

  19. Geology and structure of the Pine River, Florida River, Carbon Junction, and Basin Creek gas seeps, La Plata County, Colorado

    Science.gov (United States)

    Fassett, James E.; Condon, Steven M.; Huffman, A. Curtis; Taylor, David J.

    1997-01-01

    Introduction: This study was commissioned by a consortium consisting of the Bureau of Land Management, Durango Office; the Colorado Oil and Gas Conservation Commission; La Plata County; and all of the major gas-producing companies operating in La Plata County, Colorado. The gas-seep study project consisted of four parts; 1) detailed surface mapping of Fruitland Formation coal outcrops in the above listed seep areas, 2) detailed measurement of joint and fracture patterns in the seep areas, 3) detailed coal-bed correlation of Fruitland coals in the subsurface adjacent to the seep areas, and 4) studies of deep-seated seismic patterns in those seep areas where seismic data was available. This report is divided into three chapters labeled 1, 2, and 3. Chapter 1 contains the results of the subsurface coal-bed correla-tion study, chapter 2 contains the results of the surface geologic mapping and joint measurement study, and chapter 3, contains the results of the deep-seismic study. A preliminary draft of this report was submitted to the La Plata County Group in September 1996. All of the members of the La Plata Group were given an opportunity to critically review the draft report and their comments were the basis for revising the first draft to create this final version of a geologic report on the major La Plata County gas seeps located north of the Southern Ute Indian Reservation.

  20. Storm and flood of July 31-August 1, 1976, in the Big Thompson River and Cache la Poudre River basins, Larimer and Weld Counties, Colorado

    Science.gov (United States)

    McCain, Jerald F.; Shroba, R.R.

    1979-01-01

    PART A: Devastating flash floods swept through the canyon section of Larimer County in north-central Colorado during the night of July 31-August I, 1976, causing 139 deaths, 5 missing persons, and more than $35 million in total damages. The brunt of the storms occurred over the Big Thompson River basin between Drake and Estes Park with rainfall amounts as much as 12 inches being reported during the storm period. In the Cache la Poudre River basin to the north, a rainfall amount of 10 inches was reported for one locality while 6 inches fell over a widespread area near the central part of the basin. The storms developed when strong low-level easterly winds to the rear of a polar front pushed a moist, conditionally unstable airmass upslope into the Front Range of the Rocky Mountains. Orographic uplift released the convective instability, and light south-southeasterly winds at middle and upper levels allowed the storm complex to remain nearly stationary over the foothills for several hours. Minimal entrainment of relatively moist air at middle and upper levels, very low cloud bases, and a slightly tilted updraft structure contributed to a high precipitation efficiency. Intense rainfall began soon after 1900 MDT (Mountain Daylight Time) in the Big Thompson River and the North Fork Cache la Poudre River basins. A cumulative rainfall curve developed for Glen Comfort from radar data indicates that 7.5 inches of rain fell during the period 1930-2040 MDT on July 31. In the central part of the storm area west of Fort Collins, the heaviest rainfall began about 2200 MDT on July 31 and continued until 0100 MDT on August 1. Peak discharges were extremely large on many streams in the storm area-exceeding previously recorded maximum discharges at several locations. The peak discharge of the Big Thompson River at the gaging station at the canyon mouth, near Drake was 31,200 cubic feet per second or more than four times the previous maximum discharge of 7,600 cubic feet per second at

  1. Random versus fixed-site sampling when monitoring relative abundance of fishes in headwater streams of the upper Colorado River basin

    Science.gov (United States)

    Quist, M.C.; Gerow, K.G.; Bower, M.R.; Hubert, W.A.

    2006-01-01

    Native fishes of the upper Colorado River basin (UCRB) have declined in distribution and abundance due to habitat degradation and interactions with normative fishes. Consequently, monitoring populations of both native and nonnative fishes is important for conservation of native species. We used data collected from Muddy Creek, Wyoming (2003-2004), to compare sample size estimates using a random and a fixed-site sampling design to monitor changes in catch per unit effort (CPUE) of native bluehead suckers Catostomus discobolus, flannelmouth suckers C. latipinnis, roundtail chub Gila robusta, and speckled dace Rhinichthys osculus, as well as nonnative creek chub Semotilus atromaculatus and white suckers C. commersonii. When one-pass backpack electrofishing was used, detection of 10% or 25% changes in CPUE (fish/100 m) at 60% statistical power required 50-1,000 randomly sampled reaches among species regardless of sampling design. However, use of a fixed-site sampling design with 25-50 reaches greatly enhanced the ability to detect changes in CPUE. The addition of seining did not appreciably reduce required effort. When detection of 25-50% changes in CPUE of native and nonnative fishes is acceptable, we recommend establishment of 25-50 fixed reaches sampled by one-pass electrofishing in Muddy Creek. Because Muddy Creek has habitat and fish assemblages characteristic of other headwater streams in the UCRB, our results are likely to apply to many other streams in the basin. ?? Copyright by the American Fisheries Society 2006.

  2. Characterization of floodflows along the Arkansas River without regulation by Pueblo Reservoir, Portland to John Martin Reservoir, Southeastern Colorado

    Science.gov (United States)

    Little, John R.; Bauer, Daniel P.

    1981-01-01

    The need for a method for estimating flow characteristics of flood hydrographs between Portland, Colo., and John Martin Reservoir has been promoted with the construction of the Pueble Reservoir. To meet this need a procedure was developed for predicting floodflow peaks, traveltimes, and volumes at any point along the Arkansas River between Portland and John Martin Reservoir without considering the existing Pueble Reservoir detention effects. A streamflow-routing model was calibrated initially and then typical flood simulations were made for the 164.8-mile study reach. Simulations were completed for varying magnitudes of floods and antecedent streamflow conditions. Multiple regression techniques were then used with simulation results as input to provide predictive relationships for food peak, volume, and traveltime. Management practices that may be used to benefit water users in the area include providing methods for the distribution and allotment of the flood waters upstream of Portland to different downstream water users according to Colorado water law and also under the Arkansas River Compact. (USGS)

  3. Assessment of In-Place Oil Shale Resources of the Green River Formation, Piceance Basin, Western Colorado

    Science.gov (United States)

    Johnson, Ronald C.; Mercier, Tracey J.; Brownfield, Michael E.; Pantea, Michael P.; Self, Jesse G.

    2009-01-01

    The U.S. Geological Survey (USGS) recently completed a reassessment of in-place oil shale resources, regardless of richness, in the Eocene Green River Formation in the Piceance Basin, western Colorado. A considerable amount of oil-yield data has been collected after previous in-place assessments were published, and these data were incorporated into this new assessment. About twice as many oil-yield data points were used, and several additional oil shale intervals were included that were not assessed previously for lack of data. Oil yields are measured using the Fischer assay method. The Fischer assay method is a standardized laboratory test for determining the oil yield from oil shale that has been almost universally used to determine oil yields for Green River Formation oil shales. Fischer assay does not necessarily measure the maximum amount of oil that an oil shale can produce, and there are retorting methods that yield more than the Fischer assay yield. However, the oil yields achieved by other technologies are typically reported as a percentage of the Fischer assay oil yield, and thus Fischer assay is still considered the standard by which other methods are compared.

  4. Seasonal and spatial patterns of growth of rainbow trout in the Colorado River in Grand Canyon, AZ

    Science.gov (United States)

    Yard, Micheal D.; Korman, Josh; Walters, Carl J.; Kennedy, T.A.

    2016-01-01

    Rainbow trout (Oncorhynchus mykiss) have been purposely introduced in many regulated rivers, with inadvertent consequences on native fishes. We describe how trout growth rates and condition could be influencing trout population dynamics in a 130 km section of the Colorado River below Glen Canyon Dam based on a large-scale mark–recapture program where ∼8000 rainbow trout were recaptured over a 3-year period (2012–2014). There were strong temporal and spatial variations in growth in both length and weight as predicted from von Bertalanffy and bioenergetic models, respectively. There was more evidence for seasonal variation in the growth coefficient and annual variation in the asymptotic length. Bioenergetic models showed more variability for growth in weight across seasons and years than across reaches. These patterns were consistent with strong seasonal variation in invertebrate drift and effects of turbidity on foraging efficiency. Highest growth rates and relative condition occurred in downstream reaches with lower trout densities. Results indicate that reduction in rainbow trout abundance in Glen Canyon will likely increase trout size in the tailwater fishery and may reduce downstream dispersal into Grand Canyon.

  5. 50 CFR Table 3 to Part 226 - Hydrologic Units Containing Critical Habitat for Snake River Sockeye Salmon and Snake River...

    Science.gov (United States)

    2010-10-01

    ... Habitat for Snake River Sockeye Salmon and Snake River Spring/Summer and Fall Chinook Salmon 3 Table 3 to... Part 226—Hydrologic Units Containing Critical Habitat for Snake River Sockeye Salmon and Snake River... Snake—Asotin 17060103 17060103 17060103 Upper Grande Ronde 17060104 Wallowa 17060105 Lower Grande...

  6. Combined impacts of current and future dust deposition and regional warming on Colorado River Basin snow dynamics and hydrology

    Science.gov (United States)

    Deems, Jeffrey S.; Painter, Thomas H.; Barsugli, Joseph J.; Belnap, Jayne; Udall, Bradley

    2013-01-01

    The Colorado River provides water to 40 million people in seven western states and two countries and to 5.5 million irrigated acres. The river has long been overallocated. Climate models project runoff losses of 5–20% from the basin by mid-21st century due to human-induced climate change. Recent work has shown that decreased snow albedo from anthropogenic dust loading to the CO mountains shortens the duration of snow cover by several weeks relative to conditions prior to western expansion of the US in the mid-1800s, and advances peak runoff at Lees Ferry, Arizona, by an average of 3 weeks. Increases in evapotranspiration from earlier exposure of soils and germination of plants have been estimated to decrease annual runoff by more than 1.0 billion cubic meters, or ~5% of the annual average. This prior work was based on observed dust loadings during 2005–2008; however, 2009 and 2010 saw unprecedented levels of dust loading on snowpacks in the Upper Colorado River Basin (UCRB), being on the order of 5 times the 2005–2008 loading. Building on our prior work, we developed a new snow albedo decay parameterization based on observations in 2009/10 to mimic the radiative forcing of extreme dust deposition. We convolve low, moderate, and extreme dust/snow albedos with both historic climate forcing and two future climate scenarios via a delta method perturbation of historic records. Compared to moderate dust, extreme dust absorbs 2× to 4× the solar radiation, and shifts peak snowmelt an additional 3 weeks earlier to a total of 6 weeks earlier than pre-disturbance. The extreme dust scenario reduces annual flow volume an additional 1% (6% compared to pre-disturbance), a smaller difference than from low to moderate dust scenarios due to melt season shifting into a season of lower evaporative demand. The sensitivity of flow timing to dust radiative forcing of snow albedo is maintained under future climate scenarios, but the sensitivity of flow volume reductions decreases

  7. The Role of stocking in the reestablishment and augmentation of native fish in the Lower Colorado River mainstream (1998-2002)

    Science.gov (United States)

    Mueller, Gordon

    2003-01-01

    The Colorado River has experienced dramatic physical and biological change. Rated as the fifth largest river in the USA by volume, today its waters seldom reach the sea. Water diversions gradually reduce its flow to a point where its last remaining waters are diverted at Morales Dam leaving nearly 100 km of historic channel dry. In contrast, lower basin storage reservoirs cover 36% of the historic channel. Remaining portions of the flowing river have been channelized and straightened to a point where it now resembles a large canal. Levees, mechanical dredging, and the natural forces of erosion have degraded the river channel nearly 2 m in some locations, isolating it from its floodplain and affecting local water tables. The river no longer functions as a natural stream system characteristic of spring run-off, summer spates, and droughts. Today it serves as a water storage and conveyance system to meet human needs.

  8. Revised geologic cross sections of parts of the Colorado, White River, and Death Valley regional groundwater flow systems, Nevada, Utah, and Arizona

    Science.gov (United States)

    Page, William R.; Scheirer, Daniel S.; Langenheim, V.E.; Berger, Mary A.

    2006-01-01

    confining units because of their low permeability. Late Proterozoic to Lower Cambrian clastic units overlie the crystalline rocks and are also considered confining units within the regional flow systems. Above the clastic units are Middle Cambrian to Lower Permian carbonate rocks that are the primary aquifers in the flow systems. The Middle Cambrian to Lower Permian carbonate rocks are overlain by a sequence of mainly clastic rocks of late Paleozoic to Mesozoic age that are mostly considered confining units, but they may be permeable where faulted. Tertiary volcanic and plutonic rocks are exposed in the northern and southern parts of the study area. In the Clover and Delamar Mountains, these rocks are highly deformed by north- and northwest-striking normal and strike-slip faults that are probably important conduits in transmitting groundwater from the basins in the northern Colorado and White River flow systems to basins in the southern part of the flow systems. The youngest rocks in the region are Tertiary to Quaternary basin-fill deposits. These rocks consist of middle to late Tertiary sediments consisting of limestone, conglomerate, sandstone, tuff, and gypsum, and younger Quaternary surficial units consisting of alluvium, colluvium, playa deposits, and eolian deposits. Basin-fill deposits are both aquifers and aquitards. The rocks in the study area were complexly deformed by episodes of Mesozoic compression and Cenozoic extensional tectonism. Some Cretaceous thrust faults and folds of the Sevier orogenic belt form duplex zones and define areas of maximum thickness for the Paleozoic carbonate rocks. Cenozoic faults are important because they are the primary structures that control groundwater flow in the regional flow systems.

  9. Comparison of turbidity to multi-frequency sideways-looking acoustic-Doppler data and suspended-sediment data in the Colorado River in Grand Canyon

    Science.gov (United States)

    Voichick, Nicholas; Topping, David J.

    2010-01-01

    Water clarity is important to biologists when studying fish and other fluvial fauna and flora. Turbidity is an indicator of the cloudiness of water, or reduced water clarity, and is commonly measured using nephelometric sensors that record the scattering and absorption of light by particles in the water. Unfortunately, nephelometric sensors only operate over a narrow range of the conditions typically encountered in rivers dominated by suspended-sediment transport. For example, sediment inputs into the Colorado River in Grand Canyon caused by tributary floods often result in turbidity levels that exceed the maximum recording level of nephelometric turbidity sensors. The limited range of these sensors is one reason why acoustic Doppler profiler instrument data, not turbidity, has been used as a surrogate for suspended sediment concentration and load of the Colorado River in Grand Canyon. However, in addition to being an important water-quality parameter to biologists, turbidity of the Colorado River in Grand Canyon has been used to strengthen the suspended-sediment record through the process of turbidity-threshold sampling; high turbidity values trigger a pump sampler to collect samples of the river at critical times for gathering suspended-sediment data. Turbidity depends on several characteristics of suspended sediment including concentration, particle size, particle shape, color, and the refractive index of particles. In this paper, turbidity is compared with other parameters coupled to suspended sediment, namely suspended-silt and clay concentration and multifrequency acoustic attenuation. These data have been collected since 2005 at four stations with different sediment-supply characteristics on the Colorado River in Grand Canyon. These comparisons reveal that acoustic attenuation is a particularly useful parameter, because it is strongly related to turbidity and it can be measured by instruments that experience minimal fouling and record over the entire range

  10. Effects of mountain resort development on stream geomorphic function in the White River National Forest, Colorado, USA

    Science.gov (United States)

    David, G.

    2012-04-01

    The effects of ski slope development on morphology and stability of stream channels is poorly understood. Development of ski slopes includes tree-clearing, road construction, machine-grading and snow-making. Although, each of these types of development has been studied individually, particularly the effects of tree-clearing and road construction, the combined effect of all four on channel morphology has not been investigated thoroughly. Changes in land-use affect the hydrology of a basin by either causing an increase in the water yield or peak flow, or a change in the size and amount of sediment that the stream transports. The United States Forest Service (USFS) funded this project because of their concern with the potential impacts of development on stream channels in national forest land, where the majority of ski resorts are located. Changes in the channel morphology can result in a decrease in habitat diversity and water quality as the stream moves towards a new equilibrium. We used field data from the White River National Forest in Colorado, which includes several major ski resorts, to test the hypothesis that there is a significant difference in bank stability, undercut banks, fine sediment, wood loading, pool residual depth and D84 between the ski area "project" and reference streams, because of ski slope development. We further hypothesize that the changes in a stream are mitigated by the density and type of vegetation growing along the banks. A significant impact is defined as a project stream that is outside the range of variability of the reference streams. To test these hypotheses, we surveyed channel condition, channel dimensions, and vegetation along 47 stream reaches (200 - 800 m in length). Twenty-three "reference" streams with very little to no development in their basins are used to define reference conditions of bank stability, bank undercutting, bank height, wood loading, pool residual depth, sediment size, and vegetation structure. Twenty

  11. Yellow-billed Cuckoo Distribution, Abundance, and Habitat Use Along the Lower Colorado River and Its Tributaries, 2007 Annual Report

    Science.gov (United States)

    Johnson, Matthew J.; Durst, Scott L.; Calvo, Christopher M.; Stewart, Laura; Sogge, Mark K.; Bland, Geoffrey; Arundel, Terry R.

    2008-01-01

    This 2007 annual report details the second season of a 2-year study documenting western yellow-billed cuckoo (Coccyzus americanus occidentalis) distribution, abundance, and habitat use throughout the Lower Colorado River Multi-Species Conservation Program boundary area. We conducted cuckoo surveys at 40 sites within 14 areas, between 11 June and 9 September 2007. The 169 surveys across all sites yielded 163 yellow-billed cuckoo detections. Cuckoos were detected at 25 of the 40 sites, primarily at the Bill Williams River National Wildlife Refuge (NWR) study area (n = 139 detections; 85 percent of all detections). Detections declined slightly through the cuckoo breeding season, with most detections occurring in the first and second survey periods (n = 92; 54 percent). We detected breeding activity only at the Bill Williams River NWR, where we confirmed 27 breeding events, including two nesting observations. However, the breeding status of most detected birds was unknown. We used playback broadcast recordings to survey for yellow-billed cuckoos. Compared to simple point counts or surveys, this method increases the number of detections of this secretive, elusive species. It has long been suspected that cuckoos have a fairly low response rate, and that the standard survey method of using broadcast recordings might fail to detect all birds present in an area. In 2007, we found that the majority (84 percent) of cuckoo detections were solicited through broadcast at all study sites. The number of solicited detections was highest during the first survey period and declined as the breeding season progressed, while the number of unsolicited detections (cuckoos heard calling before broadcast was initiated) remained fairly constant through the first, second, and third survey periods. The majority (66 percent) of cuckoo detections, solicited or unsolicited, were aural, 23 percent were both heard and seen, and 11 percent were visual detections only. We also found that 50 percent

  12. Interaction of prehistoric climate, ecology, and cultures: An example from the Dolores River region of southwest Colorado

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, K.L. [Washington State Univ., Richland, WA (United States)

    1995-09-01

    Greenhouse theory suggests global climatic variation will exceed the historical records as the lower atmosphere warms in response to a rise in the concentrations of carbon dioxide, methane, and other gases. The sharp contrast between the large predicted future change and the small climatic changes recorded during the last century indicates that this later period may offer an insufficient basis for appreciating the projected future climate and vegetation changes. Examination of larger-than-historic climatic changes that have occurred in the past (such as those in the Dolores River region) provide a context for evaluating possible future changes and their implications for environmental restoration and land use planning. The zenith of Anasazi Pueblo Indian occupation in the northern Colorado Plateau region coincides with the Little Climatic Optimum (AD 900-1300), and its demise coincides with the Little Ice Age (AD 1250-1300 to AD 1850-1890). Pollen and tree-ring derived indexes of winter and summerprecipitation and growing season length were developed for the La Plata Mountains region of southwestern Colorado. The results show during the height of the Little Climatic Optimum (AD 1000-1100) the region was characterized by a relatively long growing season and by a potential dry farming zone or elevational belt twice as wide as present and supporting Anasazi upland dry farming down to at least 1600 m, an elevation impossible to dry farm today. Between AD 1100 and 1300 the potential dry-farm belt narrowed and finally disappeared with the onset of a period of markedly colder and drier conditions than current. When the Little Ice Age ended in the mid-1800s, another group of farmers (modern Anglos) were able to dry farm. If previous conditions were to return in the near future due to the effects of greenhouse warming, such conditions would be very beneficial to dry farmers.

  13. Potential effects of four Flaming Gorge Dam hydropower operational scenarios on riparian vegetation of the Green River, Utah and Colorado

    Energy Technology Data Exchange (ETDEWEB)

    LaGory, K.E.; Van Lonkhuyzen, R.A. [Argonne National Lab., IL (United States). Ecological Sciences Section

    1995-06-01

    Four hydropower operational scenarios at Flaming Gorge Dam were evaluated to determine their potential effects on riparian vegetation along the Green River in Utah and Colorado. Data collected in June 1992 indicated that elevation above the river had the largest influence on plant distribution. A lower riparian zone occupied the area between the approximate elevations of 800 and 4,200-cfs flows--the area within the range of hydropower operational releases. The lower zone was dominated by wetland plants such as cattail, common spikerush, coyote willow, juncus, and carex. An upper riparian zone was above the elevation of historical maximum power plant releases from the dam (4,200 cfs), and it generally supported plants adapted to mesic, nonwetland conditions. Common species in the upper zone included box elder, rabbitbrush, grasses, golden aster, and scouring rush. Multispectral aerial videography of the Green River was collected in May and June 1992 to determine the relationship between flow and the areas of water and the riparian zone. From these relationships, it was estimated that the upper zone would decrease in extent by about 5% with year-round high fluctuation, seasonally adjusted high fluctuation, and seasonally adjusted moderate fluctuation, but it would increase by about 8% under seasonally adjusted steady flow. The lower zone would increase by about 13% for both year-round and seasonally adjusted high fluctuation scenarios but would decrease by about 40% and 74% for seasonally adjusted moderate fluctuation and steady flows, respectively. These changes are considered to be relatively minor and would leave pre-dam riparian vegetation unaffected. Occasional high releases above power plant capacity would be needed for long-term maintenance of this relict vegetation.

  14. Design of a sediment-monitoring gaging network on ephemeral tributaries of the Colorado River in Glen, Marble, and Grand Canyons, Arizona

    Science.gov (United States)

    Griffiths, Ronald E.; Topping, David J.; Anderson, Robert S.; Hancock, Gregory S.; Melis, Theodore S.

    2014-01-01

    Management of sediment in rivers downstream from dams requires knowledge of both the sediment supply and downstream sediment transport. In some dam-regulated rivers, the amount of sediment supplied by easily measured major tributaries may overwhelm the amount of sediment supplied by the more difficult to measure lesser tributaries. In this first class of rivers, managers need only know the amount of sediment supplied by these major tributaries. However, in other regulated rivers, the cumulative amount of sediment supplied by the lesser tributaries may approach the total supplied by the major tributaries. The Colorado River downstream from Glen Canyon has been hypothesized to be one such river. If this is correct, then management of sediment in the Colorado River in the part of Glen Canyon National Recreation Area downstream from the dam and in Grand Canyon National Park may require knowledge of the sediment supply from all tributaries. Although two major tributaries, the Paria and Little Colorado Rivers, are well documented as the largest two suppliers of sediment to the Colorado River downstream from Glen Canyon Dam, the contributions of sediment supplied by the ephemeral lesser tributaries of the Colorado River in the lowermost Glen Canyon, and Marble and Grand Canyons are much less constrained. Previous studies have estimated amounts of sediment supplied by these tributaries ranging from very little to almost as much as the amount supplied by the Paria River. Because none of these previous studies relied on direct measurement of sediment transport in any of the ephemeral tributaries in Glen, Marble, or Grand Canyons, there may be significant errors in the magnitudes of sediment supplies estimated during these studies. To reduce the uncertainty in the sediment supply by better constraining the sediment yield of the ephemeral lesser tributaries, the U.S. Geological Survey Grand Canyon Monitoring and Research Center established eight sediment-monitoring gaging

  15. 2006 Progress report: Riparian willow restoration along the Illinois river at Arapahoe NWR, Colorado

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a progress report concerning riparian willow restoration on Arapahoe NWR. Riparian willow communities along the Illinois River at Arapaho NWR provide...

  16. 2005 Progress report: Riparian willow restoration along the Illinois river at Arapahoe NWR, Colorado

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a progress report concerning riparian willow restoration on Arapahoe NWR. Riparian willow communities along the Illinois River at Arapaho NWR provide...

  17. 2004 Progress report : Riparian willow restoration along the Illinois River at Arapaho NWR, Colorado

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This progress report is concerning the riparian willow restoration along the Illinois river at Arapaho NWR. Included in the report is the background on the...

  18. Continuous estimation of baseflow in snowmelt-dominated streams and rivers in the Upper Colorado River Basin: A chemical hydrograph separation approach

    Science.gov (United States)

    Miller, Matthew P.; Susong, David D.; Shope, Christopher L.; Heilweil, Victor M.; Stolp, Bernard J.

    2014-01-01

    Effective science-based management of water resources in large basins requires a qualitative understanding of hydrologic conditions and quantitative measures of the various components of the water budget, including difficult to measure components such as baseflow discharge to streams. Using widely available discharge and continuously collected specific conductance (SC) data, we adapted and applied a long established chemical hydrograph separation approach to quantify daily and representative annual baseflow discharge at fourteen streams and rivers at large spatial (> 1,000 km2 watersheds) and temporal (up to 37 years) scales in the Upper Colorado River Basin. On average, annual baseflow was 21-58% of annual stream discharge, 13-45% of discharge during snowmelt, and 40-86% of discharge during low-flow conditions. Results suggest that reservoirs may act to store baseflow discharged to the stream during snowmelt and release that baseflow during low-flow conditions, and that irrigation return flows may contribute to increases in fall baseflow in heavily irrigated watersheds. The chemical hydrograph separation approach, and associated conceptual model defined here provide a basis for the identification of land use, management, and climate effects on baseflow.

  19. An evaluation of the evolution of the latest miocene to earliest pliocene bouse lake system in the lower Colorado river valley, southwestern USA

    Science.gov (United States)

    Spencer, J.E.; Pearthree, P.A.; House, P.K.

    2008-01-01

    The upper Miocene to lower Pliocene Bouse Formation in the lower Colorado River trough of the American Southwest was deposited in three basins - from north to south, the Mohave, Havasu, and Blythe Basins - that were formed by extensional fault ing in the early to middle Miocene. Fossils of marine, brackish, and freshwater organ isms in the Bouse Formation have been interpreted to indicate an estuarine environment associated with early opening of the nearby Gulf of California. Regional uplift since 5 Ma is required to position the estuarine Bouse Formation at present elevations as high as 555 m, where greater uplift is required in the north. We present a compilation of Bouse Formation elevations that is consistent with Bouse deposition in lakes, with an abrupt 225 m northward increase in maximum Bouse elevations at Topock gorge north of Lake Havasu. Within Blythe and Havasu Basins, maximum Bouse elevations are 330 m above sea level in three widely spaced areas and reveal no evidence of regional tilting. To the north in Mohave Basin, numerous Bouse outcrops above 480 m elevation include three widely spaced sites where the Bouse Formation is exposed at 536-555 m. Numerical simulations of initial Colorado River inflow to a sequence of closed basins along the lower Colorado River corridor model a history of lake filling, spilling, evaporation and salt concentration, and outflow-channel incision. The simulations support the plausibility of evaporative concentration of Colorado River water to seawater-level salinities in Blythe Basin and indicate that such salinities could have remained stable for as long as 20-30 k.y. We infer that fossil marine organ isms in the Bouse Formation, restricted to the southern (Blythe) basin, reflect coloniza tion of a salty lake by a small number of species that were transported by birds.

  20. Water temperatures in select nearshore environments of the Colorado River in Grand Canyon, Arizona, during the Low Steady Summer Flow experiment of 2000

    Science.gov (United States)

    Vernieu, William S.; Anderson, Craig R.

    2013-01-01

    Water releases from Glen Canyon Dam, Arizona, are the primary determinant of streamflow, sediment transport, water quality, and aquatic and riparian habitat availability in the Colorado River downstream of the dam in Grand Canyon. The presence and operation of the dam have transformed the seasonally warm Colorado River into a consistently cold river because of hypolimnetic, or deep-water, releases from the penstock withdrawal structures on the dam. These releases have substantially altered the thermal regime of the downstream riverine environment. This, in turn, has affected the biota of the river corridor, particularly native and nonnative fish communities and the aquatic food web. In the spring and summer of 2000, a Low Steady Summer Flow experiment was conducted by the U.S. Geological Survey and the Bureau of Reclamation to evaluate the effects of the experimental flow on physical and biological resources of the Colorado River ecosystem downstream from Glen Canyon Dam to Lake Mead on the Arizona-Nevada border. This report describes the water temperatures collected during the experimental flow from 14 nearshore sites in the river corridor in Grand Canyon to assess the effects of steady releases on the thermal dynamics of nearshore environments. These nearshore areas are characterized by low-velocity flows with some degree of isolation from the higher velocity flows in the main channel and are hypothesized to be important rearing environments for young native fish. Water-temperature measurements were made at 14 sites, ranging from backwater to open-channel environments. Warming during daylight hours, relative to main-channel temperatures, was measured at all sites in relation to the amount of isolation from the main-channel current. Boat traffic, amount of direct solar radiation, and degree of isolation from the main-channel current appear to be the primary factors affecting the differential warming of the nearshore environment.

  1. Tributary debris fans and the late Holocene alluvial chronology of the Colorado River, eastern Grand Canyon, Arizona

    Science.gov (United States)

    Hereford, R.; Thompson, K.S.; Burke, K.J.; Fairley, H.C.

    1996-01-01

    Bouldery debris fans and sandy alluvial terraces of the Colorado River developed contemporaneously during the late Holocene at the mouths of nine major tributaries in eastern Grand Canyon. The age of the debris fans and alluvial terraces contributes to understanding river hydraulics and to the history of human activity along the river, which has been concentrated on these surfaces for at least two to three millennia. Poorly sorted, coarse-grained debris-flow deposits of several ages are interbedded with, overlie, or are overlapped by three terrace-forming alluviums. The alluvial deposits are of three age groups: the striped alluvium, deposited from before 770 B.C. to about A.D. 300; the alluvium of Pueblo II age deposited from about A.D. 700 to 1200; and the alluvium of the upper mesquite terrace, deposited from about A.D. 1400 to 1880. Two elements define the geomorphology of a typical debris fan: the large, inactive surface of the fan and a smaller, entrenched, active debris-flow channel and fan that is about one-sixth the area of the inactive fan. The inactive fan is segmented into at least three surfaces with distinctive weathering characteristics. These surfaces are conformable with underlying debris-flow deposits that date from before 770 B.C. to around A.D. 660, A.D. 660 to before A.D. 1200, and from A.D. 1200 to slightly before 1890, respectively, based on late-19th-century photographs, radiocarbon and archaeologic dating of the three stratigraphically related alluviums, and radiocarbon dating of fine-grained debris-flow deposits. These debris flows aggraded the fans in at least three stages beginning about 2.8 ka, if not earlier in the late Holocene. Several main-stem floods eroded the margin of the segmented fans, reducing fan symmetry. The entrenched, active debris-flow channels contain deposits debris fans at the mouth of the channel adjacent to the river. Early and middle Holocene debris-flow and alluvial deposits have not been recognized, as they were

  2. Comparison of 2008-2009 water years and historical water-quality data, upper Gunnison River Basin, Colorado

    Science.gov (United States)

    Solberg, Patricia A.; Moore, Bryan; Blacklock, Ty D.

    2012-01-01

    Population growth and changes in land use have the potential to affect water quality and quantity in the upper Gunnison River Basin. In 1995, the U.S. Geological Survey (USGS), in cooperation with the Bureau of Land Management, City of Gunnison, Colorado River Water Conservation District, Crested Butte South Metropolitan District, Gunnison County, Hinsdale County, Mount Crested Butte Water and Sanitation District, National Park Service, Town of Crested Butte, U.S. Forest Service, Upper Gunnison River Water Conservancy District, and Western State College, established a water-quality monitoring program in the upper Gunnison River Basin to characterize current water-quality conditions and to assess the effects of increased urban development and other land-use changes on water quality. The monitoring network has evolved into two groups of sites: (1) sites that are considered long term and (2) sites that are considered rotational. Data from the long-term sites assist in defining temporal changes in water quality (how conditions may change over time). The rotational sites assist in the spatial definition of water-quality conditions (how conditions differ throughout the basin) and address local and short-term concerns. Biannual summaries of the water-quality data from the monitoring network provide a point of reference for stakeholder discussions regarding the location and purpose of water-quality monitoring sites in the upper Gunnison River Basin. This report compares and summarizes the data collected during water years 2008 and 2009 to the historical data available at these sites. The introduction provides a map of the sampling sites, definitions of terms, and a one-page summary of selected water-quality conditions at the network sites. The remainder of the report is organized around the data collected at individual sites. Data collected during water years 2008 and 2009 are compared to historical data, State water-quality standards, and Federal water-quality guidelines

  3. A Plan for Individualizing Instruction for the Senior Government Class Through Use of Problem Solving Units. Colorado Western States Small Schools Project Documentation (Silverton High School, Silverton, Colorado, 1963-64).

    Science.gov (United States)

    Higgs, Norman E.

    During the 1963-64 school year, a secondary teacher from the rurally isolated area of Silverton, Colorado initiated an individualized program in problem solving for a senior social studies class (N=8-10). Utilizing community resources, the instructor planned several units on government, while the students selected resource materials from the…

  4. Multi-Target Calibration with a VIC Hydrologic Model: Impacts of Climate Change and Risk Assessment in the Colorado River Basin

    Science.gov (United States)

    Wi, S.; Isenstein, L.; Yang, Y. C. E.; Brown, C.

    2015-12-01

    The Variable Infiltration Capacity (VIC) model is applied to the headwaters of the Arkansas River (Colorado Springs) in the USA for the purpose of water supply evaluation. Modeling the hydrologic regime of the Arkansas River is a challenge due to the large number of diversions and regulations that might impact the natural streamflow. Since the Arkansas River headwaters are snow-melt dominated, a snow cover dataset can provide additional information during the model calibration process. Remote sensing snow data have been successfully used in previous studies coupled with hydrologic modeling to improve calibration results. Using the daily snow data acquired from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite, and this study tests different calibration schemes to determine the most suitable calibration target(s) for the Colorado Springs. First, the VIC model is calibrated to streamflow and snow alone, and then a mutli-objective optimization is utilized to calibrate the model to streamflow and snow simultaneously. A well calibrated hydrologic model can be employed particularly for climate change assessments to inform decision makers about water availability and water supply under different climate conditions. This study will provide such information to Colorado Springs in which development in terms of water supply is expected to grow considerably; increases in demands are projected to be 28% higher than the present demands (approximately 102 billion gallons) by the year 2050.

  5. Mega drought in the Colorado River Basin, water supply, and adaptive scenario planning for the Phoenix Metropolitan Area; simulations using WaterSim 5.

    Science.gov (United States)

    Sampson, D. A.

    2015-12-01

    The Decision Center for a Desert City (DCDC), a boundary organization, bridges science and policy (to foster knowledge-based decision making); we study how decisions are made in the face of uncertainty. Our water policy and management model for the Phoenix Metropolitan Area (hereafter "Phoenix"), termed WaterSim, represents one such bridging mechanism. We evaluated the effect of varying the length of drought on water availability for Phoenix. We examined droughts (starting in 2000) lasting 15, 25, and 50 years. We picked a 60-year window of runoff estimates from the paleo reconstruction data for the Colorado River (CO) (1121 through 1180 A.D.), and the two local rivers (1391 through 1450 A.D.), and assumed that the proportional difference in median flow between these periods and the long-term record represented an estimate of potential drought reductions on river flows. This resulted in a 12%, and 19% reduction in flows for the CO River and the Salt-Verde (SV) Rivers, respectively. WaterSim uses 30-year trace periods from the historical flow records to simulate river flow for future projections. We used each 30-year trace from the historical record (1906 to present, CO River; 1945 to present SV Rivers) , and default settings, to simulate 60 year projections of Lake Mead elevation and the accompanying Colorado River water shortages to Phoenix. Overall, elevations for Lake Mead fell below the 1st shortage sharing tier (1075 ft) in 83% of the simulations; 74% of the simulations fell below the 2nd tier (1050 ft), and 64% fell below the 3rd (1025 ft). Length of drought, however, determined the shortage tiers met. Median elevations for droughts ending in 2015, 2025, and 2050 were 1036, 1019, and 967 feet msl, respectively. We present the plausible water futures with adaptive anticipatory scenario planning for the projected reductions in surface water availability to demonstrate decision points for water conservation measures to effectively manage shortage conditions.

  6. Carbon export by rivers draining the conterminous United States

    Science.gov (United States)

    Stets, Edward G.; Striegl, Robert G.

    2012-01-01

    Material exports by rivers, particularly carbon exports, provide insight to basin geology, weathering, and ecological processes within the basin. Accurate accounting of those exports is valuable to understanding present, past, and projected basin-wide changes in those processes. We calculated lateral export of inorganic and organic carbon (IC and OC) from rivers draining the conterminous United States using stream gaging and water quality data from more than 100 rivers. Approximately 90% of land area and 80% of water export were included, which enabled a continental-scale estimate using minor extrapolation. Total carbon export was 41–49 Tg C yr−1. IC was >75% of export and exceeded OC export in every region except the southeastern Atlantic seaboard. The 10 largest rivers, by discharge, accounted for 66% of water export and carried 74 and 62% of IC and OC export, respectively. Watershed carbon yield for the conterminous United States was 4.2 and 1.3 g C m−2 yr−1 for IC and OC, respectively. The dominance of IC export was unexpected but is consistent with geologic models suggesting high weathering rates in the continental United States due to the prevalence of easily weathered sedimentary rock.

  7. Ecosystem ecology meets adaptive management: food web response to a controlled flood on the Colorado River, Glen Canyon

    Science.gov (United States)

    Cross, Wyatt F.; Baxter, Colden V.; Donner, Kevin C.; Rosi-Marshall, Emma J.; Kennedy, Theodore A.; Hall, Robert O.; Wellard Kelly, Holly A.; Rogers, R. Scott

    2011-01-01

    Large dams have been constructed on rivers to meet human demands for water, electricity, navigation, and recreation. As a consequence, flow and temperature regimes have been altered, strongly affecting river food webs and ecosystem processes. Experimental high-flow dam releases, i.e., controlled floods, have been implemented on the Colorado River, USA, in an effort to reestablish pulsed flood events, redistribute sediments, improve conditions for native fishes, and increase understanding of how dam operations affect physical and biological processes. We quantified secondary production and organic matter flows in the food web below Glen Canyon dam for two years prior and one year after an experimental controlled flood in March 2008. Invertebrate biomass and secondary production declined significantly following the flood (total biomass, 55% decline; total production, 56% decline), with most of the decline driven by reductions in two nonnative invertebrate taxa, Potamopyrgus antipodarum and Gammarus lacustris. Diatoms dominated the trophic basis of invertebrate production before and after the controlled flood, and the largest organic matter flows were from diatoms to the three most productive invertebrate taxa (P. antipodarum, G. lacustris, and Tubificida). In contrast to invertebrates, production of rainbow trout (Oncorhynchus mykiss) increased substantially (194%) following the flood, despite the large decline in total secondary production of the invertebrate assemblage. This counterintuitive result is reconciled by a post-flood increase in production and drift concentrations of select invertebrate prey (i.e., Chironomidae and Simuliidae) that supported a large proportion of trout production but had relatively low secondary production. In addition, interaction strengths, measured as species impact values, were strongest between rainbow trout and these two taxa before and after the flood, demonstrating that the dominant consumer—resource interactions were not

  8. Effects of climate variability on water storage in the Colorado river basin

    NARCIS (Netherlands)

    Hurkmans, R.T.W.L.; Troch, P.A.A.; Uijlenhoet, R.; Torfs, P.J.J.F.; Durcik, M.

    2009-01-01

    Understanding the long-term (interannual–decadal) variability of water availability in river basins is paramount for water resources management. Here, the authors analyze time series of simulated terrestrial water storage components, observed precipitation, and discharge spanning 74 yr in the Colora

  9. A new libelluloid family from the Eocene Green River Formation (Colorado, USA) (Odonata, Anisoptera).

    Science.gov (United States)

    Zeiri, Asma; Nel, Andre; Garrouste, Romain

    2015-10-16

    The new family Urolibellulidae is proposed for the new genus and species Urolibellula eocenica, based on a fossil dragonfly from the Eocene Green River Formation (USA). This new taxon is considered as the sister group of the extant Libellulidae. As the oldest libellulid dragonfly is dated from the Turonian, the Urolibellulidae should also be at least Late Cretaceous.

  10. Mobilization of selenium from the Mancos Shale and associated soils in the lower Uncompahgre River Basin, Colorado

    Science.gov (United States)

    Mast, M. Alisa; Mills, Taylor J.; Paschke, Suzanne S.; Keith, Gabrielle; Linard, Joshua I.

    2014-01-01

    This study investigates processes controlling mobilization of selenium in the lower part of the Uncompahgre River Basin in western Colorado. Selenium occurs naturally in the underlying Mancos Shale and is leached to groundwater and surface water by limited natural runoff, agricultural and domestic irrigation, and leakage from irrigation canals. Soil and sediment samples from the study area were tested using sequential extractions to identify the forms of selenium present in solid phases. Selenium speciation was characterized for nonirrigated and irrigated soils from an agricultural site and sediments from a wetland formed by a leaking canal. In nonirrigated areas, selenium was present in highly soluble sodium salts and gypsum. In irrigated soils, soluble forms of selenium were depleted and most selenium was associated with organic matter that was stable under near-surface weathering conditions. Laboratory leaching experiments and geochemical modeling confirm that selenium primarily is released to groundwater and surface water by dissolution of highly soluble selenium-bearing salts and gypsum present in soils and bedrock. Rates of selenium dissolution determined from column leachate experiments indicate that selenium is released most rapidly when water is applied to previously nonirrigated soils and sediment. High concentrations of extractable nitrate also were found in nonirrigated soils and bedrock that appear to be partially derived from weathered organic matter from the shale rather than from agricultural sources. Once selenium is mobilized, dissolved nitrate derived from natural sources appears to inhibit the reduction of dissolved selenium leading to elevated concentrations of selenium in groundwater. A conceptual model of selenium weathering is presented and used to explain seasonal variations in the surface-water chemistry of Loutzenhizer Arroyo, a major tributary contributor of selenium to the lower Uncompahgre River.

  11. Magnetic properties, acid neutralization capacity, and net acid production of rocks in the Animas River Watershed Silverton, Colorado

    Science.gov (United States)

    McCafferty, Anne E.; Yager, Douglas B.; Horton, Radley M.; Diehl, Sharon F.

    2006-01-01

    Federal land managers along with local stakeholders in the Upper Animas River watershed near Silverton, Colorado are actively designing and implementing mine waste remediation projects to mitigate the effects of acid mine drainage from several abandoned hard rock metal mines and mills. Local source rocks with high acid neutralization capacity (ANC) within the watershed are of interest to land managers for use in these remediation projects. A suite of representative samples was collected from propylitic to weakly sericitic-altered volcanic and plutonic rocks exposed in outcrops throughout the watershed. Acid-base accounting laboratory methods coupled with mineralogic and geochemical characterization provide insight into lithologies that have a range of ANC and net acid production (NAP). Petrophysical lab determinations of magnetic susceptibility converted to estimates for percent magnetite show correlation with the environmental properties of ANC and NAP for many of the lithologies. A goal of our study is to interpret watershed-scale airborne magnetic data for regional mapping of rocks that have varying degrees of ANC and NAP. Results of our preliminary work are presented here.

  12. Evaluation of GPM-based Multi-satellite IMERG Precipitation Products Over the Lower Colorado River Basin, Texas

    Science.gov (United States)

    Omranian, S. E.; Sharif, H. O.

    2016-12-01

    This study evaluates the Global Precipitation Measurement (GPM) satellite products by analyzing extreme rainfall events over the Lower Colorado River Basin, Texas that resulted in unprecedented flash floods in May 2015. Records of a dense rain gauge network (241 stations) are compared with Integrated Multi-satellite Retrievals for GPM (IMERG) products. The spatial resolution of the GPM satellite product is 0.1º x 0.1º and the temporal resolution is 30 minutes. Reference gauge-based observations are distributed through the basin with total area of over 5,000 square kilometers at 15-minute time intervals. A preliminary assessment of GPM-based IMERG precipitation products shows reasonable correlation, especially when for periods of high amounts of rainfall. the results indicate that GPM satellite products can potentially be employed in hydrologic modeling, especially for large events. Moreover, since the IMERG products have semi-global coverage, it can be extremely useful in hydrological modeling and analysis studies over ungauged or poorly gauged regions.

  13. Influences of fragmentation on three species of native warmwater fishes in a Colorado River Basin headwater stream system, Wyoming

    Science.gov (United States)

    Compton, R.I.; Hubert, W.A.; Rahel, F.J.; Quist, M.C.; Bower, M.R.

    2008-01-01

    We investigated the effects of constructed instream structures on movements and demographics of bluehead suckers Catostomus discobolus, flannelmouth suckers C. latipinnis, and roundtail chub Gila robusta in the upstream portion of Muddy Creek, an isolated headwater stream system in the upper Colorado River basin of Wyoming. Our objectives were to (1) evaluate upstream and downstream movements of these three native species past a small dam built to divert irrigation water from the stream and a barrier constructed to prevent upstream movements of nonnative salmonids and (2) describe population characteristics in stream segments created by these structures. Our results indicated that upstream and downstream movements of the three target fishes were common. Fish of all three species moved frequently downstream over both structures, displayed some upstream movements over the irrigation diversion dam, and did not move upstream over the fish barrier. Spawning migrations by some fish into an intermittent tributary, which was not separated from Muddy Creek by a barrier, were observed for all three species. Both the irrigation diversion dam and the fish barrier contributed to fragmentation of the native fish populations, and considerable differences in population features were observed among segments. The instream structures may eventually cause extirpation of some native species in one or more of the segments created by the structures. ?? Copyright by the American Fisheries Society 2008.

  14. Fraser River watershed, Colorado : assessment of available water-quantity and water-quality data through water year 1997

    Science.gov (United States)

    Apodaca, Lori Estelle; Bails, Jeffrey B.

    1999-01-01

    The water-quantity and water-quality data for the Fraser River watershed through water year 1997 were compiled for ground-water and surface-water sites. In order to assess the water-quality data, the data were related to land use/land cover in the watershed. Data from 81 water-quantity and water-quality sites, which consisted of 9 ground-water sites and 72 surface-water sites, were available for analysis. However, the data were limited and frequently contained only one or two water-quality analyses per site.The Fraser River flows about 28 miles from its headwaters at the Continental Divide to the confluence with the Colorado River. Ground-water resources in the watershed are used for residential and municipal drinking-water supplies. Surface water is available for use, but water diversions in the upper parts of the watershed reduce the flow in the river. Land use/land cover in the watershed is predominantly forested land, but increasing urban development has the potential to affect the quantity and quality of the water resources.Analysis of the limited ground-water data in the watershed indicates that changes in the land use/land cover affect the shallow ground-water quality. Water-quality data from eight shallow monitoring wells in the alluvial aquifer show that iron and manganese concentrations exceeded the U.S. Environmental Protection Agency secondary maximum contaminant level. Radon concentrations from these monitoring wells exceeded the U.S. Environmental Protection Agency proposed maximum contaminant level. The proposed radon contaminant level is currently being revised. The presence of volatile organic compounds at two monitoring wells in the watershed indicates that land use affects the shallow ground water. In addition, bacteria detected in three samples are at concentrations that would be a concern for public health if the water was to be used as a drinking supply. Methylene blue active substances were detected in the ground water at some sites and are a

  15. Using water, bryophytes, and macroinvertebrates to assess trace element concentrations in the Upper Colorado River Basin

    Science.gov (United States)

    Deacon, J.R.; Spahr, N.E.; Mize, S.V.; Boulger, R.W.

    2001-01-01

    This study examined trace elements concentrations and macroinvertebrate community structure at 32 sites in 22 streams in Colorado. Sites affected by mining activities (mining sites) and sites that were minimally disturbed (nonmining sites) were selected for the assessment. Water and transplanted aquatic bryophyte samples were analyzed for trace elements. Macroinvertebrate samples were collected to assess the effects of trace elements on the aquatic community of the stream. All samples of aquatic bryophytes had detectable concentrations of Cd, Cu, Pb and Zn. Principal components analysis of chemical and physical properties classified sites into three groups. The first group represented sites that were unaffected to minimally affected by mining activities; the second group was characterized by sites with Cd, Pb and Zn predominant in the mineralogy; and the third group was characterized by sites with Cu predominant in the mineralogy. Six macroinvertebrate families were common in the study area. Median values of total abundance, taxa richness and mayfly and stonefly abundance were reduced at mining sites. Abundances of Heptageniidae, Chloroperlidae and Rhyacophila and Baetis sp. also were reduced at sites with elevated trace element concentrations. Tanytarsini chironomids were most abundant at reference and minimally-disturbed sites.

  16. Late pleistocene aggradation and degradation of the lower colorado river: Perspectives from the Cottonwood area and other reconnaissance below Boulder Canyon

    Science.gov (United States)

    Lundstrom, S.C.; Mahan, S.A.; Paces, J.B.; Hudson, M.R.; House, P.K.; Malmon, D.V.; Blair, J.L.; Howard, K.A.

    2008-01-01

    Where the lower Colorado River traverses the Basin and Range Province below the Grand Canyon, significant late Pleistocene aggradation and subsequent degrada tion of the river are indicated by luminescence, paleomagnetic, and U-series data and stratigraphy. Aggradational, finely bedded reddish mud, clay, and silt are underlain and overlain by cross-bedded to plane-bedded fine sand and silt. That sequence is commonly disconformably overlain by up to 15 m of coarse sand, rounded exotic gravel, and angular, locally derived gravel. Luminescence dates on the fine sediments range from ca. 40 ka to 70 ka, considering collective uncertainties. A section of fine grained sediments over a vertical range of 15 m shows normal polarity magnetization and little apparent secular variation beyond dispersion that can be explained by com paction. Aggradation on large local tributaries such as Las Vegas Wash appears to have been coeval with that of the Colorado River. The upper limits of erosional rem nants of the sequence define a steeper grade above the historical river, and these late Pleistocene deposits are greater than 100 m above the modern river north of 35??N. Ter race gravels inset below the upper limit of the aggradational sequence yield 230Th dates that range from ca. 32 ka to 60 ka and indicate that degradation of the river system in this area closely followed aggradation. The thick sequence of rhythmically bedded mud and silt possibly indicates set tings that were ponded laterally between valley slopes and levees of the aggrading river. Potential driving mechanisms for such aggradation and degradation include sediment-yield response to climate change, drought, fire, vegetation-ecosystem dynam ics, glaciation, paleofloods, groundwater discharge, and building and destruction of natural dams produced by volcanism and landslides. ?? 2008 The Geological Society of America.

  17. Potential for Water Savings by Defoliation of Saltcedar (Tamarix spp.) by Saltcedar Beetles (Diorhabda carinulata) in the Upper Colorado River Basin

    Science.gov (United States)

    Nagler, P. L.; Nguyen, U.; Bateman, H. L.; Jarchow, C.; van Riper, C., III; Waugh, W.; Glenn, E.

    2016-12-01

    Northern saltcedar beetles (Diorhabda carinata) have spread widely in riparian zones on the Colorado Plateau since their initial release in 2002. One goal of the releases was to reduce water consumption by saltcedar in order to conserve water through reduction of evapotranspiration (ET). The beetle moved south on the Virgin River and reached Big Bend State Park in Nevada in 2014, an expansion rate of 60 km/year. This is important because the beetle's photoperiod requirement for diapause was expected to prevent them from moving south of 37°N latitude, where endangered southwest willow flycatcher habitat occurs. In addition to focusing on the rate of dispersal of the beetles, we used remote sensing estimates of ET at 13 sites on the Colorado, San Juan, Virgin and Dolores rivers and their tributaries to estimate riparian zone ET before and after beetle releases. We estimate that water savings from 2007-2015 was 31.5 million m3/yr (25,547 acre-ft/yr), amounting to 0.258 % of annual river flow from the Upper Colorado River Basin to the Lower Basin. Reasons for the relatively low potential water savings are: 1) baseline ET before beetle release was modest (0.472 m/yr); 2) reduction in ET was low (0.061 m/yr) because saltcedar stands tended to recover after defoliation; 3) riparian ET even in the absence of beetles was only 1.8 % of river flows, calculated as the before beetle average annual ET (472 mm/yr) times the total area of saltcedar (51,588 ha) divided by the combined total average annual flows (1964-2015) from the upper to lower catchment areas of the Colorado River Basin at the USGS gages (12,215 million m3/yr or 9.90 million acre-ft). Further research is suggested to concentrate on the ecological impacts (both positive and negative) of beetles on riparian zones and on identifying management options to maximize riparian health.

  18. Temporal inconsistencies in coarse-scale snow water equivalent patterns: Colorado River Basin snow telemetry-topography regressions

    Directory of Open Access Journals (Sweden)

    Fassnacht, S. R.

    2012-05-01

    Full Text Available The relation between snow water equivalent (SWE and 28 variables (27 topographically-based topographic variables and canopy density for the Colorado River Basin, USA was explored through a multi-variate regression. These variables include location, slope and aspect at different scales, derived variables to indicate the distance to sources of moisture and proximity to and characteristics of obstacles between these moisture sources and areas of snow accumulation, and canopy density. A weekly time step of snow telemetry (SNOTEL SWE data from 1990 through 1999 was used. The most important variables were elevation and regional scale (81 km² slope. Since the seasonal and inter-annual variability is high, a regression relationship should be formulated for each time step. The inter-annual variation in the relation between SWE and topographic variables partially corresponded with the amount of snow accumulated over the season and the El Niño Southern Oscillation cycle.Se analiza la relación entre el equivalente de agua en la nieve (SWE y 28 variables (27 variables topográficas y otra basada en la densidad del dosel para la Cuenca del Río Colorado, EE.UU. mediante regresión multivariante. Estas variables incluyen la localización, pendiente y orientación a diferentes escalas, además de variables derivadas para indicar la distancia a las fuentes de humedad y la proximidad a las barreras topográficas, además de las características de las barreras topográficas entre las fuentes de humedad, las áreas de acumulación de nieve y la densidad del dosel. Se utilizaron telemetrías semanales de nieve (SNOTEL desde 1990 hasta 1999. Las variables más importantes fueron la elevación y la pendiente a escala regional (81 km². Dada la alta variabilidad estacional e interanual, fue necesario establecer regresiones específicas para cada intervalo disponible de datos. La variación interanual en la relación entre variables topográficas y el SWE se

  19. Organic Carbon Inventories and Vertical Fluxes Through the Vadose Zone into Groundwater at the Rifle, Colorado River Floodplain Site

    Science.gov (United States)

    Tokunaga, T. K.; Wan, J.; Dong, W.; Williams, K. H.; Robbins, M.; Kim, Y.; Faybishenko, B.; Conrad, M. E.; Christensen, J. N.; Gilbert, B.; Dayvault, R. D.; Long, P. E.; Hubbard, S. S.

    2013-12-01

    Understanding carbon inventories and fluxes within the vadose zone and groundwater of semi-arid regions is challenging because of their typically deep profiles, moderately low soil organic carbon (SOC) inventories, low dissolved organic carbon (DOC) fluxes, and slow changes in soil inorganic carbon (SIC) inventories. The remediated uranium/vanadium mill tailings site situated on a floodplain at Rifle, Colorado possesses a number of characteristics that facilitate investigation of subsurface carbon fluxes. These include locally derived fill soil having SOC and SIC concentrations representative of the region, established vegetation cover (perennial grasses and shrubs) on the fill, boundaries between the fill and underlying alluvium distinguishable through concentrations of SIC and other chemical components, predictable groundwater flow and interaction with the adjacent Colorado River, and a clearly delineated impermeable lower boundary (Wasatch Formation shale) at depths ranging from 6 to 7.5 m. Environmental characteristics of this site permit year-round sampling of both pore water and pore gas throughout most of the moderately deep (~ 3.5 m) vadose zone. Within this well-defined hydrological system, we recently installed a suite of tensiometers, pore water (vadose zone and groundwater) samplers, gas samplers, and neutron probe access tubes at three sites along a transect aligned with the groundwater flow direction in order to determine inventories and fluxes of water, carbon, and other components. The tensiometer and piezometer measurements are revealing impacts of infiltration and groundwater recharge events, evapotranspiration, and capillary fringe-groundwater interactions. The results of pore water analyses are showing relatively high concentrations of DOC (up to 4 mM) in the vadose zone, and particulate organic carbon (POC) mobile in the capillary fringe. Differences in DOC characteristics are being determined using a variety of analytical techniques. Hydraulic

  20. Determination of pre-mining geochemical conditions and paleoecology in the Animas River Watershed, Colorado

    Science.gov (United States)

    Church, S.E.; Fey, D.L.; Brouwers, E.M.; Holmes, C.W.; Blair, Robert

    1999-01-01

    Determination of the pre-mining geochemical baseline in bed sediments and the paleoecology in a watershed impacted by historical mining activity is of utmost importance in establishing watershed restoration goals. We have approached this problem in the Animas River watershed using geomorphologic mapping methods to identify old pre-mining sediments. A systematic evaluation of possible sites resulted in collection of a large number of samples of pre-mining sediments, overbank sediments, and fluvial tailings deposits from more than 50 sites throughout the watershed. Chemical analysis of individual stratigraphic layers has resulted in a chemical stratigraphy that can be tied to the historical record through geochronological and dendochronological studies at these sites. Preliminary analysis of geochemical data from more than 500 samples from this study, when coupled with both the historical and geochronological record, clearly show that there has been a major impact by historical mining activities on the geochemical record preserved in these fluvial bed sediments. Historical mining activity has resulted in a substantial increase in metals in the very fine sand to clay sized component of the bed sediment of the upper Animas River, and Cement and Mineral Creeks. Enrichment factors for metals in modern bed sediments, relative to the pre-mining sediments, range from a factor of 2 to 6 for arsenic, 4 to more than 10 for cadmium, 2 to more than 10 for lead, 2 to 5 for silver, and 2 to more than 15 for zinc. However, the pre-mining bed sediment geochemical baseline is high relative to crustal abundance levels of many orerelated metals and the watershed would readily be identified as a highly mineralized area suitable for mineral exploration if it had not been disturbed by historical mining activity. We infer from these data that the water chemistry in the streams was less acidic prior to historical mining activity in the watershed. Paleoentologic evidence does not indicate a

  1. Tracing the Sources of Macrolide Antibiotics and Illicit Drugs into the Lower Colorado River Basin

    Science.gov (United States)

    A number of pharmaceuticals have been detected in surface waters across the United States. Antibiotics present in the environment can produce resistance in microorganisms, which could potentially have adverse effects on human health. In addition, while the ecotoxicological signif...

  2. Tracing the Sources of Macrolide Antibiotics and Illicit Drugs into the Lower Colorado River Basin

    Science.gov (United States)

    A number of pharmaceuticals have been detected in surface waters across the United States. Antibiotics present in the environment can produce resistance in microorganisms, which could potentially have adverse effects on human health. In addition, while the ecotoxicological signif...

  3. Review of water right allocation in Colorado River and its enlightenment%科罗拉多河水权分配历程及其启示

    Institute of Scientific and Technical Information of China (English)

    周婷; 郑航

    2015-01-01

    为把握和吸取科罗拉多河近百年来水权分配的规律及经验,对科罗拉多河在美国境内及美国和墨西哥之间的水权分配历程进行了全面梳理和归纳,重点阐述了各条约及措施的背景、目的、内容及相互联系。从科罗拉多河水权分配历程可以看出,流域水权的保障是工程措施和非工程措施协同发展的结果,同时应考虑自然条件、区域社会经济发展、生态环境和国际环境等综合因素;在水权条约的框架下,灵活的市场机制能够提高水资源利用效率,是应对水资源供需变化的有效方式。科罗拉多河水权分配历程对于中国国际河流水权维护及国内水资源优化配置具有重要的借鉴价值。%This study comprehensively concluded the water right allocation course of the Colorado River in America and America—Mexico to seize and learn the century⁃long water right law and the situation of the Colorado River. Each water law focuses remarks on the background, purpose, content, and their relationships. The water right allocation course of the Colorado River demonstrates that the persistence of the water right is assured by the cooperative develop⁃ment of both engineering and non⁃engineering measures. Meanwhile, natural resources, regional socio⁃economic devel⁃opment, ecology, and international environment should also be considered. Under the water right treaty framework, flexible market mechanisms can improve water resource efficiency, which is an effective manner in addressing changes in the demand and supply of water resources. The water right allocation of the Colorado River has an important refer⁃ence value for China in both claiming transboundary river water right and optimizing local water resource management.

  4. Modern landscape processes affecting archaeological sites along the Colorado River corridor downstream of Glen Canyon Dam, Glen Canyon National Recreation Area, Arizona

    Science.gov (United States)

    East, Amy E.; Sankey, Joel B.; Fairley, Helen C.; Caster, Joshua J.; Kasprak, Alan

    2017-08-29

    The landscape of the Colorado River through Glen Canyon National Recreation Area formed over many thousands of years and was modified substantially after the completion of Glen Canyon Dam in 1963. Changes to river flow, sediment supply, channel base level, lateral extent of sedimentary terraces, and vegetation in the post-dam era have modified the river-corridor landscape and have altered the effects of geologic processes that continue to shape the landscape and its cultural resources. The Glen Canyon reach of the Colorado River downstream of Glen Canyon Dam hosts many archaeological sites that are prone to erosion in this changing landscape. This study uses field evaluations from 2016 and aerial photographs from 1952, 1973, 1984, and 1996 to characterize changes in potential windblown sand supply and drainage configuration that have occurred over more than six decades at 54 archaeological sites in Glen Canyon and uppermost Marble Canyon. To assess landscape change at these sites, we use two complementary geomorphic classification systems. The first evaluates the potential for aeolian (windblown) transport of river-derived sand from the active river channel to higher elevation archaeological sites. The second identifies whether rills, gullies, or arroyos (that is, overland drainages that erode the ground surface) exist at the archaeological sites as well as the geomorphic surface, and therefore the relative base level, to which those flow paths drain. Results of these assessments are intended to aid in the management of irreplaceable archaeological resources by the National Park Service and stakeholders of the Glen Canyon Dam Adaptive Management Program.

  5. Effects of colloids on metal transport in a river receiving acid mine drainage, upper Arkansas River, Colorado, U.S.A.

    Science.gov (United States)

    Kimball, Briant A.

    1995-01-01

    Inflows of metal-rich, acidic water that drain from mine dumps and tailings piles in the Leadville, Colorado, area enter the non-acidic water in the upper Arkansas River. Hydrous iron oxides precipitate as colloids and move downstream in suspension, particularly downstream from California Gulch, which has been the major source of metal loads. The colloids influence the concentrations of metals dissolved in the water and the concentrations in bed sediments. To determine the role of colloids, samples of water, colloids, and fine-grained bed sediment were obtained at stream-gaging sites on the upper Arkansas River and at the mouths of major tributaries over a 250-km reach. Dissolved and colloidal metal concentrations in the water column were operationally defined using tangential-flow filtration through 0.001-pm membranes to separate the water and the colloids. Surface-extractable and total bed sediment metal concentrations were obtained on the Iron dominated the colloid composition, but substantial concentrations of As, Cd, Cu, Mn, Pb, and Zn also occurred in the colloidal solids. The colloidal load decreased by one half in the first 50 km downstream from the mining inflows due to sedimentation of aggregated colloids to the streambed. Nevertheless, a substantial load of colloids was transported through the entire study reach to Pueblo Reservoir. Dissolved metals were dominated by Mn and Zn, and their concentrations remained relatively high throughout the 250-km reach. The composition of extractable and total metals in bed sediment for several kilometers downstream from California Gulch is similar to the composition of the colloids that settle to the bed. Substantial concentrations of Mn and Zn were extractable, which is consistent with sediment-water chemical reaction. Concentrations of Cd, Pb, and Zn in bed sediment clearly result from the influence of mining near Leadville. Concentrations of Fe and Cu in bed sediments are nearly equal to concentrations in colloids

  6. Analysis of the geochemical gradient created by surface-groundwater interactions within riverbanks of the East River in Crested Butte, Colorado

    Science.gov (United States)

    Lunzer, J.; Williams, K. H.; Malenda, H. F.; Nararne-Sitchler, A.

    2016-12-01

    An improved understanding of the geochemical gradient created by the mixing of surface and groundwater of a river system will have considerable impact on our understanding of microorganisms, organic cycling and biogeochemical processes within these zones. In this study, the geochemical gradient in the hyporheic zone is described using a variety of geochemical properties. A system of shallow groundwater wells were installed in a series of transects along a stream bank. Each transect consists of several wells that progress away from the river bank in a perpendicular fashion. From these wells, temperature, conductivity and pH of water samples were obtained via hand pumping or bailing. These data show a clear geochemical gradient that displays a distinct zone in the subsurface where the geochemical conditions change from surface water dominated to groundwater dominated. For this study, the East River near Crested Butte, Colorado has been selected as the river of interest due the river being a relatively undisturbed floodplain. Additionally, the specific section chosen on the East River displays relatively high sinuosity meaning that these meandering sections will produce hyporheic zones that are more laterally expansive than what would be expected on a river of lower sinuosity. This increase in lateral extension of the hyporheic zone will make depicting the subtle changes in the geochemical gradient much easier than that of a river system in which the hyporheic zone is not as laterally extensive. Data has been and will be continued to be collected at different river discharges to evaluate the geochemical gradient at differing rates. Overall, this characterization of the geochemical gradient along stream banks will produce results that will aid in the further use of geochemical methods to classify and understand hyporheic exchange zones and the potential expansion of these techniques to river systems of differing geologic and geographic conditions.

  7. Potential effects of four Flaming Gorge Dam hydropower operational scenarios on the fishes of the Green River, Utah and Colorado

    Energy Technology Data Exchange (ETDEWEB)

    Hlohowskyj, I.; Hayse, J.W.

    1995-09-01

    Aerial videography and modeling were used to evaluate the impacts of four hydropower operational scenarios at Flaming Gorge Dam, Utah, on trout and native fishes in the Green River, Utah and Colorado. The four operational scenarios studied were year-round high fluctuations, seasonally adjusted high fluctuations, seasonally adjusted moderate fluctuations, and seasonally adjusted steady flows. Impacts on trout were evaluated by examining differences among scenarios in the areas of inundated substrates that serve as spawning and feeding habitat. All scenarios would provide at least 23 acres per mile of habitat for spawning and food production; seasonally adjusted operations would provide additional areas during periods of sustained high release. Seasonally adjusted high fluctuations would increase inundated areas by 12 to 26% for a short period in winter and spring, but food production and reproduction would not be expected to increase. Seasonally adjusted moderate fluctuations and steady flows would produce similar increases in area, but the longer period of inundation could also result in increased food production and provide additional spawning sites for trout. Impacts on native fishes were assessed by examining daily changes in backwater nursery areas. Compared with year-round high fluctuations, the daily changes in backwater area would decrease by about 47, 89, and 100% under the seasonally adjusted high fluctuation, moderate fluctuation, and steady flow scenarios, respectively. Similarly, daily stage fluctuations during the nursery period would decrease by 72, 89, and 100% under the seasonally adjusted high fluctuation, moderate fluctuation, and steady flow scenarios, respectively. These reductions in daily fluctuations in backwater area and stage would improve conditions in nursery habitats and could in turn improve recruitment and overwinter survival. Introduced fish species could also benefit from the seasonally adjusted operational scenarios.

  8. Structural Geometry of a Sector of the Colorado River Delta, Baja California, Mexico, Based on Seismic Reflections

    Science.gov (United States)

    Chanes-Martínez, J. Juan; González-Escobar, Mario; Suárez-Vidal, Francisco; Gallardo-Mata, Clemente G.

    2014-07-01

    A structural study in the SW section of the Colorado River delta using seismic reflection data is presented. The study area is located along the Cerro Prieto transform fault, which extends from the northern Gulf of California through the Mexicali Valley and is an active fault within the Pacific-North American plate boundary zone. The research was supported by a database of five seismic profiles with a total length of 215 km, collected in the early 80's by Petróleos Mexicanos. The results show a high density of faults, most of which are buried by sediments. Within the Cerro Prieto fault zone, several faults were identified, such as: Palmas, Mesa, and Pangas Viejas, until now unknown. In addition, even though the Indiviso fault was investigated and superficially identify prior to this work, herein mapped at depth. West of the Cerro Prieto fault zone lies the Las Tinajas basin, bound by the Dunas and Saldaña faults and by the Montague basin to the southeast. The deformation zone along the plate boundary is 18-km-wide, stretching from the Cerro Prieto fault in the east to the Pangas Viejas fault in the west. The orientations of the faults are NW-SE, and if projected from the southern side of the Sierra Cucapah southward, the faults tend to join the Cerro Prieto fault. In the Las Tinajas basin, the acoustic basement is deeper than 5,000 m. Some of the largest vertical displacements generated by the 2010 7.2-Mw El Mayor-Cucapah earthquake occurred southeast of the epicenter and coincided with the location of the Pangas Viejas Fault, which is buried by sediments. Before this event, seismic activity was very low, and no structures were known in the area. In this paper, we demonstrate that there are at least seven major faults that may now pose a high seismic hazard.

  9. Importance of Organic Matter-Uranium Biogeochemistry to Uranium Plume Persistence in the Upper Colorado River Basin

    Science.gov (United States)

    Bargar, J.; Janot, N.; Jones, M. E.; Bone, S. E.; Lezama-Pacheco, J.; Fendorf, S. E.; Long, P. E.; Williams, K. H.; Bush, R. P.

    2014-12-01

    Recent evidence suggests that biologically driven redox reactions, fueled by sedimentary lenses enriched in detrital organic matter, play major roles in maintaining the persistent uranium groundwater plume in the subsurface at the U.S. Department of Enery's Rifle, CO field research site. Biogeochemical cycling of C, N, Fe, and S is highly active in these organic-rich naturally reduced zones (NRZs), and uranium is present as U(IV). The speciation of these elements profoundly influences the susceptibility of uranium to be reoxidized and remobiliized and contribute to plume persistence. However, uranim speciation in particular is poorly constrained in these sytems. To better evaluate the importance of NRZs to uranium mobility and plume persistence at the Rifle site, the DOE-BER-funded SLAC SFA team has characterized vertical concentration profiles and speciation of uranium, iron, sulfur, and NOM in well bores at high spatial resolution (4 inch intervals). Up to 95% of the sedimentary uranium pool was found to be concentrated in NRZs, where it occurs dominantly as non-crystalline forms of U(IV). Uranium accumulation and the presence of the short-lived sulfide mackinawite (FeS) at NRZ-aquifer interfaces indicate that NRZs actively exchange solutes with the surrounding aquifer. Moreover, sediment textures indicate that NRZs are likely to be abundant in riparian zones throughout the upper Colorado River basin (U.S.A.), which contains most of the contaminated DOE legacy uranium ore processing sites in the U.S. These results suggest that NRZ-uranium interactions may be important to plume persistence regionally and emphasize the importance of understanding molecular-scale processes.

  10. Status and trends of the rainbow trout population in the Lees Ferry reach of the Colorado River downstream from Glen Canyon Dam, Arizona, 1991–2009

    Science.gov (United States)

    Makinster, Andrew S.; Persons, William R.; Avery, Luke A.

    2011-01-01

    The Lees Ferry reach of the Colorado River, a 25-kilometer segment of river located immediately downstream from Glen Canyon Dam, has contained a nonnative rainbow trout (Oncorhynchus mykiss) sport fishery since it was first stocked in 1964. The fishery has evolved over time in response to changes in dam operations and fish management. Long-term monitoring of the rainbow trout population downstream of Glen Canyon Dam is an essential component of the Glen Canyon Dam Adaptive Management Program. A standardized sampling design was implemented in 1991 and has changed several times in response to independent, external scientific-review recommendations and budget constraints. Population metrics (catch per unit effort, proportional stock density, and relative condition) were estimated from 1991 to 2009 by combining data collected at fixed sampling sites during this time period and at random sampling sites from 2002 to 2009. The validity of combining population metrics for data collected at fixed and random sites was confirmed by a one-way analysis of variance by fish-length class size. Analysis of the rainbow trout population metrics from 1991 to 2009 showed that the abundance of rainbow trout increased from 1991 to 1997, following implementation of a more steady flow regime, but declined from about 2000 to 2007. Abundance in 2008 and 2009 was high compared to previous years, which was likely the result of increased early survival caused by improved habitat conditions following the 2008 high-flow experiment at Glen Canyon Dam. Proportional stock density declined between 1991 and 2006, reflecting increased natural reproduction and large numbers of small fish in samples. Since 2001, the proportional stock density has been relatively stable. Relative condition varied with size class of rainbow trout but has been relatively stable since 1991 for fish smaller than 152 millimeters (mm), except for a substantial decrease in 2009. Relative condition was more variable for larger

  11. Remote Sensing-based Estimates of Potential Evapotranspiration for Hydrologic Modeling in the Upper Colorado River Basin Region

    Science.gov (United States)

    Barik, Muhammad Ghulam

    Potential Evapotranspiration (PET) is used as a common input to calculate evaporative demand in hydrological, ecological and biological modeling. Dynamic and distributed measurement of PET is important for improved hydrologic predictions at the watershed scale since PET varies with time and space. In this work, an advanced dynamic PET estimation is proposed by integrating geostationary satellite products into a currently existing remote sensing-based PET algorithm and evaluated in the framework of operational hydrologic forecasting modeling. The development work is approached through a series of studies. At first, a previously developed Moderate Resolution Imaging Spectroradiometer (MODIS) based PET (MODIS-PET) product applied over several flux towers and basins in the Upper Colorado River Basin (UCRB) to determine its applicability and predictive ability in comparison to other ground based distributed PET methods. Results from this primary study indicate the MODIS-PET is an improved PET estimation method compared to the other two contemporary distributed PET products that were tested over this geographically complex study region. In addition to elevation and cloud cover, uncertainties are associated with the MODIS-PET algorithm pertaining from three model variables; land surface temperature, air temperature and surface emissivity. The crude hypothetical sinusoidal curve considered in the conversion of instantaneous MODIS-PET to the daily PET estimation can potentially be replaced with satellite data with improved temporal resolution. Hence, integration of Geostationary Operational Environmental Satellites (GOES), a series of geostationary satellites with frequent observations, data in the MODIS-PET algorithm is performed in the second part. The coupling of GOES within the MODIS-PET algorithm shows significant improvement over the previously developed stand-alone MODIS-PET product, especially for cloudy days and high temperature pixels. Finally, evaluation of these

  12. Geophysical, geochemical, mineralogical, and enivronmental data for rock samples collected in a mineralized volcanic environment, upper Animas River watershed, Colorado

    Science.gov (United States)

    McCafferty, A.E.; Horton, R.J.; Stanton, M.R.; McDougal, R.R.; Fey, D.L.

    2011-01-01

    This report provides analyses of 90 rock samples collected in the upper Animas River watershed near Silverton, Colo., from 2001 to 2007. The samples are analyzed for geophysical, geochemical, mineralogical, and environmental rock properties of acid neutralizing capacity and net acid production. The database is derived from both published (n=68) and unpublished (n=32) data. New for all samples are geophysical measurements of electrical resistivity, density, and porosity. Rock samples were acquired from 12 geologic units that include key Tertiary volcanic and plutonic lithologies, all with varying degrees of alteration.

  13. Report of progress of stream measurements for the calendar year 1905, Part XI, Colorado River drainage above Yuma

    Science.gov (United States)

    Hinderlider, M.C.; Swendsen, G.L.

    1906-01-01

    The hydrographic work of the United States Geological Survey includes the collection of facts concerning and the study of conditions affecting the behavior of water from the time it reaches the earh as rain or snow until it joins the oceans or great navigable rivers. These investigations became a distinct feature of the work of the Survey in the fall of 1888, when an instruction camp was established at Embudo, N. Mex. The frist specific appropriation for gaging streams was amde by the act of August 18, 1894, which contained an item of $12, 500 'for gaging the streams and determining the water supply of the United States, including the investigation of underground currents and artesian wells in the arid and semiarid sections.'

  14. Computation and analysis of the instantaneous-discharge record for the Colorado River at Lees Ferry, Arizona : May 8, 1921, through September 30, 2000

    Science.gov (United States)

    Topping, David J.; Schmidt, John C.; Vierra, L.E.

    2003-01-01

    A gaging station has been operated by the U.S. Geological Survey at Lees Ferry, Arizona, since May 8, 1921. In March 1963, Glen Canyon Dam was closed 15.5 miles upstream, cutting off the upstream sediment supply and regulating the discharge of the Colorado River at Lees Ferry for the first time in history. To evaluate the pre-dam variability in the hydrology of the Colorado River, and to determine the effect of the operation of Glen Canyon Dam on the downstream hydrology of the river, a continuous record of the instantaneous discharge of the river at Lees Ferry was constructed and analyzed for the entire period of record between May 8, 1921, and September 30, 2000. This effort involved retrieval from the Federal Records Centers and then synthesis of all the raw historical data collected by the U.S. Geological Survey at Lees Ferry. As part of this process, the peak discharges of the two largest historical floods at Lees Ferry, the 1884 and 1921 floods, were reanalyzed and recomputed. This reanalysis indicates that the peak discharge of the 1884 flood was 210,000?30,000 cubic feet per second (ft3/s), and the peak discharge of the 1921 flood was 170,000?20,000 ft3/s. These values are indistinguishable from the peak discharges of these floods originally estimated or published by the U.S. Geological Survey, but are substantially less than the currently accepted peak discharges of these floods. The entire continuous record of instantaneous discharge of the Colorado River at Lees Ferry can now be requested from the U.S. Geological Survey Grand Canyon Monitoring and Research Center, Flagstaff, Arizona, and is also available electronically at http://www.gcmrc.gov. This record is perhaps the longest (almost 80 years) high-resolution (mostly 15- to 30-minute precision) times series of river discharge available. Analyses of these data, therefore, provide an unparalleled characterization of both the natural variability in the discharge of a river and the effects of dam

  15. Description of chronostratigraphic units preserved as channel deposits and geomorphic processes following a basin-scale disturbance by a wildfire in Colorado

    Science.gov (United States)

    Moody, John A.; Martin, Deborah A.

    2017-10-11

    The consequence of a 1996 wildfire disturbance and a subsequent high-intensity summer convective rain storm (about 110 millimeters per hour) was the deposition of a sediment superslug in the Spring Creek basin (26.8 square kilometers) of the Front Range Mountains in Colorado. Spring Creek is a tributary to the South Platte River upstream from Strontia Springs Reservoir, which supplies domestic water for the cities of Denver and Aurora. Changes in a superslug were monitored over the course of 18 years (1996–2014) by repeat surveys at 18 channel cross sections spaced at nearly equal intervals along a 1,500-meter study reach and by a time series of photographs of each cross section. Surveys were not repeated at regular time intervals but after major changes caused by different geomorphic processes. The focus of this long-term study was to understand the evolution and internal alluvial architecture of chronostratigraphic units (defined as the volume of sediment deposited between two successive surveys), and the preservation or storage of these units in the superslug. The data are presented as a series of 18 narratives (one for each cross section) that summarize the changes, illustrate these changes with photographs, and provide a preservation plot showing the amount of each chronostratigraphic unit still remaining in June 2014.The most significant hydrologic change after the wildfire was an exponential decrease in peak discharge of flash floods caused by summer convective rain storms. In response to these hydrologic changes, all 18 locations went through an aggradation phase, an incision phase, and finally a stabilization phase. However, the architecture of the chronostratigraphic units differs from cross section to cross section, and units are characterized by either a laminar, fragmented, or hybrid alluvial architecture. In response to the decrease in peak-flood discharge and the increase in hillslope and riparian vegetation, Spring Creek abandoned many of the

  16. Relations of benthic macroinvertebrates to concentrations of trace elements in water, streambed sediments, and transplanted bryophytes and stream habitat conditions in nonmining and mining areas of the upper Colorado River basin, Colorado, 1995-98

    Science.gov (United States)

    Mize, Scott V.; Deacon, Jeffrey R.

    2002-01-01

    Intensive mining activity and highly mineralized rock formations have had significant impacts on surface-water and streambed-sediment quality and aquatic life within the upper reaches of the Uncompahgre River in western Colorado. A synoptic study by the U.S. Geological Survey National Water-Quality Assessment Program was completed in the upper Uncompahgre River Basin in 1998 to better understand the relations of trace elements (with emphasis on aluminum, arsenic, copper, iron, lead, and zinc concentrations) in water, streambed sediment, and aquatic life. Water-chemistry, streambed-sediment, and benthic macroinvertebrate samples were collected during low-flow conditions between October 1995 and July 1998 at five sites on the upper Uncompahgre River, all downstream from historical mining, and at three sites in drainage basins of the Upper Colorado River where mining has not occurred. Aquatic bryophytes were transplanted to all sites for 15 days of exposure to the water column during which time field parameters were measured and chemical water-quality and benthic macroinvertebrate samples were collected. Stream habitat characteristics also were documented at each site. Certain attributes of surface-water chemistry among streams were significantly different. Concentrations of total aluminum, copper, iron, lead, and zinc in the water column and concentrations of dissolved aluminum, copper, and zinc were significantly different between nonmining and mining sites. Some sites associated with mining exceeded Colorado acute aquatic-life standards for aluminum, copper, and zinc and exceeded Colorado chronic aquatic-life standards for aluminum, copper, iron, lead, and zinc. Concentrations of copper, lead, and zinc in streambed sediments were significantly different between nonmining and mining sites. Generally, concentrations of arsenic, copper, lead, and zinc in streambed sediments at mining sites exceeded the Canadian Sediment Quality Guidelines probable effect level (PEL

  17. WaterSMART-The Colorado River Basin focus-area study

    Science.gov (United States)

    Bruce, Breton W.

    2012-01-01

    Increasing demand for the limited water resources of the United States continues to put pressure on water-resource agencies to balance the competing needs of ecosystem health with municipal, agricultural, and recreational uses. In 2007, the U.S. Geological Survey (USGS) identified a National Water Census as one of six pivotal future science directions for the USGS in the following decade. The envisioned USGS National Water Census would evaluate large-scale effects of changes in land use and land cover, water use, and climate on water availability, water quality, and human and aquatic ecosystem health. The passage of the SECURE (Science and Engineering to Comprehensively Understand and Responsibly Enhance) Water Act in 2009 was a key step towards implementing the USGS National Water Census. Section 9508 of the Act authorizes a "national water availability and use assessment program" within the USGS (1) to provide a more accurate assessment of the status of the water resources of the United States; and (2) to develop the science for improved forecasts of the availability of water for future economic, energy production, and environmental uses. Initial funding for the USGS to begin working on the National Water Census came with the approval of the U.S. Department of the Interior's WaterSMART (Sustain and Manage America's Resources for Tomorrow) Initiative. The WaterSMART Initiative provides funding to the USGS, Bureau of Reclamation, and U.S. Department of Energy to achieve a sustainable water strategy to meet the Nation's water needs. WaterSMART funding also allowed the USGS to begin the national Water Availability and Use Assessment, as called for under the SECURE Water Act.

  18. Descriptions of the Animas River-Cement Creek confluence and mixing zone near Silverton, Colorado, during the late summers of 1996 and 1997

    Science.gov (United States)

    Schemel, Laurence E.; Cox, Marisa H.

    2005-01-01

    Acidic waters from Cement Creek discharge into the circum-neutral Animas River in a high-elevation region of the San Juan Mountains near Silverton, Colorado. Cement Creek is acidic and enriched in metals and sulfate because it is fed by discharges from abandoned mines and natural mineral deposits. Mixing with the Animas River raises the pH and produces precipitates of iron and aluminum (oxy)hydroxides, which in turn can adsorb other metals. This confluence was studied in 1996 and 1997 to better understand mixing and sorption processes which are common during the neutralization of acidic streams. The photographs in this report show flow braiding and other features that influenced the way the two streams mixed during the late summers of the two years. They also show 'banding' due to incomplete mixing and 'opalescence' due to chemical reactions and the formation of colloidal-size particles in the mixing zone.

  19. Data from synoptic water-quality studies on the Colorado River in the Grand Canyon, Arizona, November 1990 and June 1991

    Science.gov (United States)

    Taylor, H.E.; Peart, D.B.; Antweiler, R.C.; Brinton, T.I.; Campbell, W.L.; Barbarino, J.R.; Roth, D.A.; Hart, R.J.; Averett, R.C.

    1996-01-01

    Two water-quality synoptic studies were made on the Colorado River in the Grand Canyon, Arizona. Field measurements and the collection of water samples for laboratory analysis were made at 10 mainstem and 6 tributary sites every 6 hours for a 48-hour period on November 5-6, 1990, and again on June 18-20, 1991. Field measurements included discharge, alkalinity, water temperature, light penetration, pH, specific conductance, and dissolved oxygen. Water samples were collected for the laboratory analysis of major and minor ions (calcium, magnesium, sodium, potassium, strontium, chloride, sulfate, silica as SiO2), trace elements (aluminum, arsenic, boron, barium, beryllium, cadmium, cobalt, chromium, copper, iron, lead, lithium, manganese, molybdenum, nickel, selenium, thallium, uranium, vanadium and zinc), and nutrients (phosphate, nitrate, ammonium, nitrite, total dissolved nitrogen, total dissolved phosphorus and dissolved organic carbon). Biological measurements included drift (benthic invertebrates and detrital material), and benthic invertebrates from the river bottom.

  20. Viability of male gametes in common carp (Cyprinus carpio) along the Lower Colorado River from the Cibola National Wildlife Refuge (NWR), Havasu NWR, and Lake Mohave of Lake Mead National Recreation Area

    Science.gov (United States)

    Jenkins, Jill A.; Goodbred, Steven L.

    2005-01-01

    To contribute to an investigation on possible endocrine impacts in three sites along the lower Colorado River in Arizona, especially in male fishes, this study addressed the null hypothesis that aquatic species in southern sites did not exhibit evidence of endocrine disruption as compared with those in nonimpacted sites. The results presented are intended to provide managers with science-based information and interpretations about the reproductive condition of biota in their habitat along the lower Colorado River to minimize any potential adverse effects to trust fish and wildlife resources and to identify water resources of acceptable quality. In particular, these data can inform decision making about wastewater discharges into the Colorado River that directly supplies water to Arizona refuges located along the river. These data are integral to the USFWS proposal entitled 'AZ - Endocrine Disruption in Razorback Sucker and Common Carp on National Wildlife Refuges along the Lower Colorado River' that was proposed to assess evidence of endocrine disruption in carp and razorback suckers downstream of Hoover Dam.

  1. Groundwater Quality, Age, and Probability of Contamination, Eagle River Watershed Valley-Fill Aquifer, North-Central Colorado, 2006-2007

    Science.gov (United States)

    Rupert, Michael G.; Plummer, L. Niel

    2009-01-01

    The Eagle River watershed is located near the destination resort town of Vail, Colorado. The area has a fastgrowing permanent population, and the resort industry is rapidly expanding. A large percentage of the land undergoing development to support that growth overlies the Eagle River watershed valley-fill aquifer (ERWVFA), which likely has a high predisposition to groundwater contamination. As development continues, local organizations need tools to evaluate potential land-development effects on ground- and surface-water resources so that informed land-use and water management decisions can be made. To help develop these tools, the U.S. Geological Survey (USGS), in cooperation with Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority, conducted a study in 2006-2007 of the groundwater quality, age, and probability of contamination in the ERWVFA, north-central Colorado. Ground- and surface-water quality samples were analyzed for major ions, nutrients, stable isotopes of hydrogen and oxygen in water, tritium, dissolved gases, chlorofluorocarbons (CFCs), and volatile organic compounds (VOCs) determined with very low-level laboratory methods. The major-ion data indicate that groundwaters in the ERWVFA can be classified into two major groups: groundwater that was recharged by infiltration of surface water, and groundwater that had less immediate recharge from surface water and had elevated sulfate concentrations. Sulfate concentrations exceeded the USEPA National Secondary Drinking Water Regulations (250 milligrams per liter) in many wells near Eagle, Gypsum, and Dotsero. The predominant source of sulfate to groundwater in the Eagle River watershed is the Eagle Valley Evaporite, which is a gypsum deposit of Pennsylvanian age located predominantly in the western one-half of Eagle County.

  2. Factors controlling the abundance of rainbow trout in the Colorado River in Grand Canyon in a reach utilized by endangered humpback chub

    Science.gov (United States)

    Korman, Josh; Yard, Michael D.; Yackulic, Charles B.

    2015-01-01

    We estimated the abundance, survival, movement, and recruitment of non-native rainbow trout in the Colorado River in Grand Canyon to determine what controls their abundance near the Little Colorado River (LCR) confluence where endangered humpback chub rear. Over a 3-year period, we tagged more than 70,000 trout and recovered over 8,200 tagged fish. Trout density was highest (10,000-25,000 fish/km) in the reach closest to Glen Canyon Dam where the majority of trout recruitment occurs, and was 30-50-fold lower (200-800 fish/km) in reaches near the LCR confluence ~100 km downstream. The extent of rainbow trout movement was limited with less than 1% of recaptures making movements greater than 20 km. However, due to high trout densities in upstream source areas, this small dispersal rate was sufficient to explain the 3-fold increase in the relatively small population near the LCR. Reducing dispersal rates of trout from upstream sources is the most feasible solution to maintain low densities near the LCR to minimize negative effects of competition and predation on humpback chub.

  3. Influence of Riparian Tree Phenology on Lower Colorado River Spring-Migrating Birds: Implications of Flower Cueing

    Science.gov (United States)

    McGrath, Laura J.; van Riper, Charles

    2005-01-01

    Executive Summary Neotropical migrant birds make choices about which habitats are most likely to provide successful foraging locations during migration, but little is known about how these birds recognize and process environmental clues that indicate the presence of prey species. Aspects of tree phenology, notably flowering of trees along the lower Colorado River corridor, coincide with the migratory stopovers of leaf-gleaning insectivorous songbirds and may be an important indicator of arthropod prey species availability. Shifting tree flowering and leaf flush during the spring migration period presents avian insectivores with an assortment of foraging opportunities. During two field seasons at Cibola National Wildlife Refuge in southwestern Arizona, we examined riparian tree species to test whether leaf-gleaning insectivorous birds are attracted to the flowering condition of trees in choosing foraging sites. We predicted that flowering trees would host more insect prey resources, would thus show increased visit rates, length of stays and attack ratios of migrant avian insectivores, and that those arthropods would be found in the stomach contents of the birds. Paired trees of honey mesquite (Prosopis glandulosa), displaying heavy and light degrees of flowering were observed to test these predictions. To test whether birds are tracking arthropods directly or are using flowers as a proximate cue, we removed flowers from selected trees and paired these treated trees with neighboring high flowering trees, which served as controls. Avian foraging behavior, avian diets, arthropods, and phenology data were collected at the same time to control for temporal differences in insect availability, plant phenology, and differences in stopover arrivals of birds. We documented five patterns from this study: 1) Higher abundance and richness of arthropods were found on honey mesquite trees with greater numbers of flowers. 2) Arthropod abundance and richness increased as flowering

  4. The impacts of ski slope development on stream channel morphology in the White River National Forest, Colorado, USA

    Science.gov (United States)

    David, Gabrielle C. L.; Bledsoe, Brian P.; Merritt, David M.; Wohl, Ellen

    2009-02-01

    The combined influence of tree-clearing, road construction, snowmaking, and machine-grading can cause increased flow and sediment loads along streams in or adjacent to commercial ski resorts. These changes to stream channels can increase bank failures, bed material size, pool scour, and, in extreme cases, channel incision. We used field data from the White River National Forest in Colorado, which includes several major ski resorts, to test the hypothesis that ski slope development causes a significant difference in bank stability, undercut banks, fine sediment, wood load, pool residual depth, and particle size ( D84) between the ski area project streams and reference streams. We further hypothesize that the changes in a stream are mitigated by the density and type of vegetation growing along the banks. A significant difference is defined as a project stream that is outside the range of variability of the reference streams. To test these hypotheses, we surveyed channel conditions, channel dimensions, and vegetation along 47 stream reaches (200-300 m in length). Twenty-four of these streams are within ski areas (project streams), either adjacent to or downstream from ski slopes. Twenty-three reference streams with very little to no development in their basins are used to define reference conditions of bank stability, bank undercutting, bank height, wood load, pool residual depth, sediment size, and vegetation structure. A combination of statistical techniques, including Principal Components Analysis and Classification and Regression Tree Analysis, was used to assess the controls on stream channel morphology and to analyze the differences between project and reference streams. Project streams that are significantly different than reference streams have a combination of a higher percentage of fine sediment, smaller pool residual depth, and higher percentage of unstable banks. The impacted project streams have bed material derived from granitic rocks and a lower density

  5. Quantification and Simulation of Metal Loading to the Upper Animas River, Eureka to Silverton, San Juan County, Colorado, September 1997 and August 1998

    Science.gov (United States)

    Paschke, Suzanne S.; Kimball, Briant A.; Runkel, Robert L.

    2005-01-01

    Drainage from abandoned and inactive mines and from naturally mineralized areas in the San Juan Mountains of southern Colorado contributes metals to the upper Animas River near Silverton, Colorado. Tracer-injection studies and associated synoptic sampling were performed along two reaches of the upper Animas River to develop detailed profiles of stream discharge and to locate and quantify sources of metal loading. One tracer-injection study was performed in September 1997 on the Animas River reach from Howardsville to Silverton, and a second study was performed in August 1998 on the stream reach from Eureka to Howardsville. Drainage in the upper Animas River study reaches contributed aluminum, calcium, copper, iron, magnesium, manganese, sulfate, and zinc to the surface-water system in 1997 and 1998. Colloidal aluminum, dissolved copper, and dissolved zinc were attenuated through a braided stream reach downstream from Eureka. Instream dissolved copper concentrations were lower than the State of Colorado acute and chronic toxicity standards downstream from the braided reach to Silverton. Dissolved iron load and concentrations increased downstream from Howardsville and Arrastra Gulch, and colloidal iron remained constant at low concentrations downstream from Howardsville. Instream sulfate concentrations were lower than the U.S. Environmental Protection Agency's secondary drinking-water standard of 250 milligrams per liter throughout the two study reaches. Elevated zinc concentrations are the primary concern for aquatic life in the upper Animas River. In the 1998 Eureka to Howardsville study, instream dissolved zinc load increased downstream from the Forest Queen mine, the Kittimack tailings, and Howardsville. In the 1997 Howardsville to Silverton study, there were four primary areas where zinc load increased. First, was the increase downstream from Howardsville and abandoned mining sites downstream from the Cunningham Gulch confluence, which also was measured during

  6. Ground-water resources of the South Platte River Basin in western Adams and southwestern Weld Counties, Colorado

    Science.gov (United States)

    Smith, Rex O.; Schneider, P.A.; Petri, Lester R.

    1964-01-01

    The area described in this report consists of about 970 square miles in western Adams and southwestern Weld Counties in northeastern Colorado. It includes that part of the South Platte River valley between Denver and Kuner, Colo., all of Beebe Draw, and the lower part of the valley of Box Elder Creek. The stream-valley lowlands are separated by rolling uplands. The climate is semiarid, the normal annual precipitation being about 13 inches; thus, irrigation is essential for stable agricultural development. The area contains about 220,000 acres of irrigated land in the stream valleys. Most of the remaining 400,000 acres of land is used for dry farming or grazing because it lacks irrigation water. Most of the lowlands were brought under irrigation with surface water during the early 1900's, and now nearly all the surface water in the area is appropriated for irrigation within and downstream from the area. Because the natural flow of the streams is sometimes less than the demand for water, ground water is used to supplement the surface-water supply. Wells, drilled chiefly since 1930, supply the supplemental water and in some places are the sole supply for irrigation use. Rocks exposed in the area are of sedimentary origin and range in age from Lato Cretaceous to Recent. Those that are consolidated, called 'bedrock' in this report, consist of the Fox Hills sandstone and the Laramie and Arapahoe formations, all of Late Cretaceous age, and the Denver formation and Dawson arkose of Late Cretaceous and Tertiary age. The surface of the bedrock was shaped by ancestral streams, the valleys of which are reflected by the present surface topography. Dune sand, slope wash, and thin upland deposits of Quaternary age mantle the bedrock in the divide areas, and stream deposits ranging in thickness from 0 to about 125 feet partly fill the ancestral valleys. The valley-fill deposits consist of beds and lenses of clay, silt, sand, gravel, cobbles, and boulders. Abundant supplies of

  7. Techniques for Monitoring Razorback Sucker in the Lower Colorado River, Hoover to Parker Dams, 2006-2007, Final Report

    Science.gov (United States)

    Mueller, Gordon A.; Wydoski, Richard; Best, Eric; Hiebert, Steve; Lantow, Jeff; Santee, Mark; Goettlicher, Bill; Millosovich, Joe

    2008-01-01

    Trammel netting is generally the accepted method of monitoring razorback sucker in reservoirs, but this method is ineffective for monitoring this fish in rivers. Trammel nets set in the current become fouled with debris, and nets set in backwaters capture high numbers of nontarget species. Nontargeted fish composed 97 percent of fish captured in previous studies (1999-2005). In 2005, discovery of a large spawning aggregation of razorback sucker in midchannel near Needles, Calif., prompted the development of more effective methods to monitor this and possibly other riverine fish populations. This study examined the effectiveness of four methods of monitoring razorback sucker in a riverine environment. Hoop netting, electrofishing, boat surveys, and aerial photography were evaluated in terms of data accuracy, costs, stress on targeted fish, and effect on nontargeted fish as compared with trammel netting. Trammel netting in the riverine portion of the Colorado River downstream of Davis Dam, Arizona-Nevada yielded an average of 43 razorback suckers a year (1999 to 2005). Capture rates averaged 0.5 razorback suckers per staff day effort, at a cost exceeding $1,100 per fish. Population estimates calculated for 2003-2005 were 3,570 (95 percent confidence limits [CL] = 1,306i??i??i??-8,925), 1,768 (CL = 878-3,867) and 1,652 (CL = 706-5,164); wide confidence ranges reflect the small sample size. By-catch associated with trammel netting included common carp, game fish and, occasionally, shorebirds, waterfowl, and muskrats. Hoop nets were prone to downstream drift owing to design and anchoring problems aggravated by hydropower ramping. Tests were dropped after the 2006 field season and replaced with electrofishing. Electrofishing at night during low flow and when spawning razorback suckers moved to the shoreline proved extremely effective. In 2006 and 2007, 263 and 299 (respectively) razorback suckers were taken. Capture rates averaged 8.3 razorback suckers per staff day at a

  8. Chapter A. Effects of urbanization on stream ecosystems in the South Platte River basin, Colorado and Wyoming

    Science.gov (United States)

    Sprague, Lori A.; Zuellig, Robert E.; Dupree, Jean A.

    2006-01-01

    This report describes the effects of urbanization on physical, chemical, and biological characteristics of stream ecosystems in 28 basins along an urban land-use gradient in the South Platte River Basin, Colorado and Wyoming, from 2002 through 2003. Study basins were chosen to minimize natural variability among basins due to factors such as geology, elevation, and climate and to maximize coverage of different stages of urban development among basins. Because land use or population density alone often are not a complete measure of urbanization, land use, land cover, infrastructure, and socioeconomic variables were integrated in a multimetric urban intensity index to represent the degree of urban development in each study basin. Physical characteristics studied included stream hydrology, stream temperature, and habitat; chemical characteristics studied included nutrients, pesticides, suspended sediment, sulfate, chloride, and fecal bacteria concentrations; and biological characteristics studied included algae, fish, and invertebrate communities. Semipermeable membrane devices (SPMDs), passive samplers that concentrate trace levels of hydrophobic organic contaminants like polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), also were used. The objectives of the study were to (1) examine physical, chemical, and biological responses along the gradient of urbanization; (2) determine the major physical, chemical, and landscape variables affecting the structure of aquatic communities; and (3) evaluate the relevance of the results to the management of water resources in the South Platte River Basin. Commonly observed effects of urbanization on instream physical, chemical, and biological characteristics, such as increased flashiness, higher magnitude and more frequent peak flows, increased concentrations of chemicals, and changes in aquatic community structure, generally were not observed in this study. None of the hydrologic, temperature, habitat

  9. Controls on selenium distribution and mobilization in an irrigated shallow groundwater system underlain by Mancos Shale, Uncompahgre River Basin, Colorado, USA

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Taylor J.; Mast, M. Alisa; Thomas, Judith; Keith, Gabrielle

    2016-10-01

    Elevated selenium (Se) concentrations in surface water and groundwater have become a concern in areas of the Western United States due to the deleterious effects of Se on aquatic ecosystems. Elevated Se concentrations are most prevalent in irrigated alluvial valleys underlain by Se-bearing marine shales where Se can be leached from geologic materials into the shallow groundwater and surface water systems. This study presents groundwater chemistry and solid-phase geochemical data from the Uncompahgre River Basin in Western Colorado, an irrigated alluvial landscape underlain by Se-rich Cretaceous marine shale. We analyzed Se species, major and trace elements, and stable nitrogen and oxygen isotopes of nitrate in groundwater and aquifer sediments to examine processes governing selenium release and transport in the shallow groundwater system. Groundwater Se concentrations ranged from below detection limit (< 0.5 μg L{sup −1}) to 4070 μg L{sup −1}, and primarily are controlled by high groundwater nitrate concentrations that maintain oxidizing conditions in the aquifer despite low dissolved oxygen concentrations. High nitrate concentrations in non-irrigated soils and nitrate isotopes indicate nitrate is largely derived from natural sources in the Mancos Shale and alluvial material. Thus, in contrast to areas that receive substantial NO{sub 3} inputs through inorganic fertilizer application, Se mitigation efforts that involve limiting NO{sub 3} application might have little impact on groundwater Se concentrations in the study area. Soluble salts are the primary source of Se to the groundwater system in the study area at-present, but they constitute a small percentage of the total Se content of core material. Sequential extraction results indicate insoluble Se is likely composed of reduced Se in recalcitrant organic matter or discrete selenide phases. Oxidation of reduced Se species that constitute the majority of the Se pool in the study area could be a potential

  10. Evapotranspiration by remote sensing: An analysis of the Colorado River Delta before and after the Minute 319 pulse flow to Mexico

    Science.gov (United States)

    Jarchow, Christopher J.; Nagler, Pamela L.; Glenn, Edward P.; Ramirez-Hernandez, Jorge; Rodriguez-Burgueno, Eliana

    2017-01-01

    The unique hydrologic conditions characterizing riparian ecosystems in dryland (arid and semi-arid) areas help maintain high biodiversity and support high levels of primary productivity compared to associated uplands. In western North America, many riparian ecosystems have been damaged by altered flow regimes (e.g., impoundments and diversions) and over utilization of water resources (e.g., groundwater pumping for agriculture and human consumption). This has led some state and national governments to provide occasional environmental flows to address the declining condition of such riparian systems. In a historic agreement between the United States and Mexico, 130 million cubic meters (mcm) of water was released to the lower Colorado River Delta in Mexico, with the intent to evaluate the hydrological and biological response of the ecosystem. We used the Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) to estimate long term (2000–2014) and short term (pre- and post-pulse; 2013 and 2014) evapotranspiration (ET; used herein as an indicator of plant health) of the delta’s riparian corridor. We found the pulse flow helped reverse a decline in ET from 2011 to 2013, with a small, but statistically significant increase in 2014 (P < 0.05). ET was greater than 100 mcm in all years analyzed (even in years without surface flows) and exceeded surface flows in all years except 2000 (result of excess flows following an El Niño cycle in 1997) and 2014 (year of the pulse flow). Based on groundwater salinities and MODIS ET estimates, we estimated groundwater flow into the delta to be ∼103 mcm. Shallow groundwater salinities in the riparian zone increased from 1.30 g L−1 in the most upstream reach to 2.77 g L−1 in the most downstream reach we measured, partly due to uptake of water by riparian vegetation and partly to intrusion of saline agricultural return flows. The disparity between surface flows and ET can likely be

  11. Catchment-flowline network and selected model inputs for an enhanced and updated spatially referenced statistical assessment of dissolved-solids load sources and transport in streams of the Upper Colorado River Basin

    Science.gov (United States)

    Buto, Susan G.; Spangler, Lawrence E.; Flint, Alan L.; Flint, Lorraine E.

    2017-01-01

    This USGS data release consists of the synthetic stream network and associated catchments used to develop spatially referenced regressions on watershed attributes (SPARROW) model of dissolved-solids sources and transport in the Upper Colorado River Basin as well as geology and selected Basin Characterization Model (BCM) data used as input to the model.

  12. Using large-scale flow experiments to rehabilitate Colorado River ecosystem function in Grand Canyon: Basis for an adaptive climate-resilient strategy: Chapter 17

    Science.gov (United States)

    Melis, Theodore S.; Pine, William E.; Korman, Josh; Yard, Michael D.; Jain, Shaleen; Pulwarty, Roger S.; Miller, Kathleen; Hamlet, Alan F.; Kenney, Douglas S.; Redmond, Kelly T.

    2016-01-01

    Adaptive management of Glen Canyon Dam is improving downstream resources of the Colorado River in Glen Canyon National Recreation Area and Grand Canyon National Park. The Glen Canyon Dam Adaptive Management Program (AMP), a federal advisory committee of 25 members with diverse special interests tasked to advise the U.S. Department of the Interior), was established in 1997 in response to the 1992 Grand Canyon Protection Act. Adaptive management assumes that ecosystem responses to management policies are inherently complex and unpredictable, but that understanding and management can be improved through monitoring. Best known for its high-flow experiments intended to benefit physical and biological resources by simulating one aspect of pre-dam conditions—floods, the AMP promotes collaboration among tribal, recreation, hydropower, environmental, water and other natural resource management interests. Monitoring has shown that high flow experiments move limited new tributary sand inputs below the dam from the bottom of the Colorado River to shorelines; rebuilding eroded sandbars that support camping areas and other natural and cultural resources. Spring-timed high flows have also been shown to stimulate aquatic productivity by disturbing the river bed below the dam in Glen Canyon. Understanding about how nonnative tailwater rainbow trout (Oncorhynchus mykiss), and downstream endangered humpback chub (Gila cypha) respond to dam operations has also increased, but this learning has mostly posed “surprise” adaptation opportunities to managers. Since reoperation of the dam to Modified Low Fluctuating Flows in 1996, rainbow trout now benefit from more stable daily flows and high spring releases, but possibly at a risk to humpback chub and other native fishes downstream. In contrast, humpback chub have so far proven robust to all flows, and native fish have increased under the combination of warmer river temperatures associated with reduced storage in Lake Powell, and a

  13. Hydrology and Ecology of the Colorado River Delta in the Face of Changing Climate and Land Use Practices: the Next Fifty Years

    Science.gov (United States)

    Nagler, P. L.; Glenn, E. P.

    2007-12-01

    The Lower Colorado River Delta in the U.S. and Mexico is an internationally important aquatic biome, supporting fresh water and estuarine wetlands and a riparian corridor rich in avian and other wildlife. These rich ecosystems could be severely harmed by invasive species interacting with projected climate change and land use practices over the next 50 years. It is critical to measure land cover and monitor ecosystem and land use changes because these ecosystems are supported by fresh and brackish water flows originating from flood control releases and agricultural return flows in the U.S. and Mexico. Most climate models project a drying trend in the Colorado River watershed due to global warming, decreasing the frequency of flood releases to the Delta. Total basin water storage in the reservoir system is expected to be reduced by 32-40 percent, and flow volume is expected to meet demands in only 59-75 percent of years in 50 years. The frequency of spills (years in which water is released from the reservoirs to the Delta) will decrease under a global warming scenario. However, the Pacific Decadal Oscillation and ENSO events will continue to introduce variability into river flows, and there will still be years in which water is spilled to the Delta. Agricultural return flows will decrease as more water is diverted from agriculture to metropolitan use in both countries. The salinity of the ground water in Mexico, which currently supports cottonwood and willow trees in the riparian corridor, is increasing at a rate of about 20 ppm per year, and in 50 years it might be too saline for cottonwoods and willows. The riparian zone may become dominated by saltcedar and other salt-tolerant shrubs, degrading the habitat for birds and other wildlife. As flows to the Delta diminish, monitoring and active restoration projects to maintain trees and wetlands will be needed to preserve habitat value.

  14. Geologic map of the Clifton Quadrangle, Mesa County, Colorado

    Science.gov (United States)

    Carrara, P.E.

    2001-01-01

    1:24,000-scale geologic mapping in the Clifton 7.5' quadrangle, in support of the USGS Colorado River/I-70 Corridor Cooperative Geologic Mapping Project, provides interpretations of the Quaternary stratigraphy and geologic hazards in this area of the Grand Valley. The Clifton 1:24,000 quadrangle is in Mesa County in western Colorado. Because the map area is dominated by various surficial deposits, the map depicts 16 different Quaternary units. Five prominent river terraces are present in the quadrangle containing gravels deposited by the Colorado River. The map area contains a large landslide deposit on the southern slopes of Mount Garfield. The landslide developed in the Mancos Shale and contains large blocks of the overlying Mesaverde Group. In addition, the landslide is a source of debris flows that have closed I-70 in the past. The major bedrock unit in the quadrangle is the Mancos Shale of Upper Cretaceous age. The map is accompanied by text containing unit descriptions, and sections on geologic hazards (including landslides, piping, gullying, expansive soils, and flooding), and economic geology (including sand and gravel). A table indicates what map units are susceptible to a given hazard. Approximately 20 references are cited at the end of the report.

  15. Persistent organic pollutants in fish tissue in the mid-continental great rivers of the United States

    Science.gov (United States)

    The great rivers of the central United States (Upper Mississippi, Missouri, and Ohio rivers) are significant economic and cultural resources, but their ecological condition is not well quantified. The Environmental Monitoring and Assessment Program for Great River Ecosystems (EMA...

  16. 77 FR 74781 - Safety Zones; Columbia Grain and United Grain Corporation Facilities; Columbia and Willamette Rivers

    Science.gov (United States)

    2012-12-18

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zones; Columbia Grain and United Grain.... SUMMARY: The Coast Guard is establishing temporary safety zones around the Columbia Grain facility on the Willamette River in Portland, OR, and the United Grain Corporation facility on the Columbia River in...

  17. 78 FR 16302 - Crystal River Unit 3 Nuclear Generating Plant, Application for Amendment to Facility Operating...

    Science.gov (United States)

    2013-03-14

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Crystal River Unit 3 Nuclear Generating Plant, Application for Amendment to Facility Operating... Operating License No. DPR-72 for the Crystal River Unit 3 Nuclear Generating Plant (CR-3), located in...

  18. 76 FR 53972 - Florida Power Corporation, Crystal River Unit No. 3 Nuclear Generating Plant; Notice of...

    Science.gov (United States)

    2011-08-30

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Florida Power Corporation, Crystal River Unit No. 3 Nuclear Generating Plant; Notice of... Facility Operating License No. DPR-72 for Crystal River Unit 3 Nuclear generating Plant (CR-3), currently...

  19. Temporal and spatial variability of ammonia in urban and agricultural regions of northern Colorado, United States

    Science.gov (United States)

    Li, Yi; Thompson, Tammy M.; Van Damme, Martin; Chen, Xi; Benedict, Katherine B.; Shao, Yixing; Day, Derek; Boris, Alexandra; Sullivan, Amy P.; Ham, Jay; Whitburn, Simon; Clarisse, Lieven; Coheur, Pierre-François; Collett, Jeffrey L., Jr.

    2017-05-01

    Concentrated agricultural activities and animal feeding operations in the northeastern plains of Colorado represent an important source of atmospheric ammonia (NH3). The NH3 from these sources contributes to regional fine particle formation and to nitrogen deposition to sensitive ecosystems in Rocky Mountain National Park (RMNP), located ˜ 80 km to the west. In order to better understand temporal and spatial differences in NH3 concentrations in this source region, weekly concentrations of NH3 were measured at 14 locations during the summers of 2010 to 2015 using Radiello passive NH3 samplers. Weekly (biweekly in 2015) average NH3 concentrations ranged from 2.66 to 42.7 µg m-3, with the highest concentrations near large concentrated animal feeding operations (CAFOs). The annual summertime mean NH3 concentrations were stable in this region from 2010 to 2015, providing a baseline against which concentration changes associated with future changes in regional NH3 emissions can be assessed. Vertical profiles of NH3 were also measured on the 300 m Boulder Atmospheric Observatory (BAO) tower throughout 2012. The highest NH3 concentration along the vertical profile was always observed at the 10 m height (annual average concentration of 4.63 µg m-3), decreasing toward the surface (4.35 µg m-3) and toward higher altitudes (1.93 µg m-3). The NH3 spatial distributions measured using the passive samplers are compared with NH3 columns retrieved by the Infrared Atmospheric Sounding Interferometer (IASI) satellite and concentrations simulated by the Comprehensive Air Quality Model with Extensions (CAMx). The satellite comparison adds to a growing body of evidence that IASI column retrievals of NH3 provide very useful insight into regional variability in atmospheric NH3, in this case even in a region with strong local sources and sharp spatial gradients. The CAMx comparison indicates that the model does a reasonable job simulating NH3 concentrations near sources but tends to

  20. Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Surficial Geology

    Science.gov (United States)

    Wieczorek, Michael E.; LaMotte, Andrew E.

    2010-01-01

    This tabular data set represents the area of surficial geology types in square meters compiled for every MRB_E2RF1 catchment of selected Major River Basins (MRBs, Crawford and others, 2006). The source data set is the "Digital data set describing surficial geology in the conterminous US" (Clawges and Price, 1999).The MRB_E2RF1 catchments are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2008). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

  1. The Role of Eolian Sediment in the Preservation of Archeologic Sites Along the Colorado River Corridor in Grand Canyon National Park, Arizona

    Science.gov (United States)

    Draut, Amy E.; Rubin, David M.

    2008-01-01

    Since the closure of Glen Canyon Dam in 1963, the natural hydrologic and sedimentary systems along the Colorado River in the Grand Canyon reach have changed substantially (see, for example, Andrews, 1986; Johnson and Carothers, 1987; Webb and others, 1999b; Rubin and others, 2002; Topping and others, 2003; Wright and others, 2005; Hazel and others, 2006b). The dam has reduced the fluvial sediment supply at the upstream boundary of Grand Canyon National Park by about 95 percent. Regulation of river discharge by dam operations has important implications for the storage and redistribution of sediment in the Colorado River corridor. In the absence of floods, sediment is not deposited at elevations that regularly received sediment before dam closure. Riparian vegetation has colonized areas at lower elevations than in predam time when annual floods removed young vegetation (Turner and Karpiscak, 1980). Together, these factors have caused a systemwide decrease in the size and number of subaerially exposed fluvial sand deposits since the 1960s, punctuated by episodic aggradation during the exceptional high-flow intervals in 1983-84, 1996, and 2004 and by sediment input from occasional tributary floods (Beus and others, 1985; Schmidt and Graf, 1987; Kearsley and others, 1994; Hazel and others, 1999; Schmidt and others, 2004; Wright and others, 2005). When the Bureau of Reclamation sponsored the creation of the Glen Canyon Environmental Studies (GCES) research initiative in 1982, research objectives included physical and biologic resources, whereas the effects of dam operations on cultural resources were not addressed (Fairley and others, 1994; Fairley, 2003). In the early 1980s, it was widely believed that because few archeologic sites were preserved within the river's annual-flood zone, cultural features would not be greatly affected by dam operations. Recent studies, however, indicate that alterations in the flow and sediment load of the Colorado River by Glen Canyon Dam

  2. Self-sedimented diatom mats as agents of exceptional fossil preservation in the Oligocene Florissant lake beds, Colorado, United States

    Science.gov (United States)

    Harding, Ian C.; Chant, Loraine S.

    2000-03-01

    Microbial mats play a major role in the formation of exceptionally preserved fossil deposits by overgrowing and binding organic remains and sedimentary particles. This minimizes hydrodynamic and biological disruption of dead organisms and sedimentary laminae, but published works all implicate prokaryotic cyanobacteria as the microbial agent. However, exceptionally well preserved macrofossils of the Oligocene Florissant lake beds (Colorado, United States) are enveloped in matted aggregations of mucous-secreting, pennate diatom frustules. It is suggested that the macrobiota became entrapped in mucous-secreting mats of surface water blooms of planktonic diatoms in lake Florissant. As the mats and the incorporated macrobiota were sedimented out of the water column, the mucosic mats and their associated bacterial communities arrested decay and promoted preservation of refractory tissues. Thus, by a completely different mechanism, the diatom mats fulfilled the same preservational role previously suggested for cyanobacterial mats. This hitherto unrecognized mode of preservation may be an important causative factor in the formation of exceptionally preserved lacustrine fossil biotas.

  3. A comparison of macroinvertebrate and habitat methods of data collection in the Little Colorado River Watershed, Arizona 2007

    Science.gov (United States)

    Spindler, Patrice; Paretti, Nick V.

    2007-01-01

    The Arizona Department of Environmental Quality (ADEQ) and the U.S. Environmental Protection Agency (USEPA) Ecological Monitoring and Assessment Program (EMAP), use different field methods for collecting macroinvertebrate samples and habitat data for bioassessment purposes. Arizona’s Biocriteria index was developed using a riffle habitat sampling methodology, whereas the EMAP method employs a multi-habitat sampling protocol. There was a need to demonstrate comparability of these different bioassessment methodologies to allow use of the EMAP multi-habitat protocol for both statewide probabilistic assessments for integration of the EMAP data into the national (305b) assessment and for targeted in-state bioassessments for 303d determinations of standards violations and impaired aquatic life conditions. The purpose of this study was to evaluate whether the two methods yield similar bioassessment results, such that the data could be used interchangeably in water quality assessments. In this Regional EMAP grant funded project, a probabilistic survey of 30 sites in the Little Colorado River basin was conducted in the spring of 2007. Macroinvertebrate and habitat data were collected using both ADEQ and EMAP sampling methods, from adjacent reaches within these stream channels. All analyses indicated that the two macroinvertebrate sampling methods were significantly correlated. ADEQ and EMAP samples were classified into the same scoring categories (meeting, inconclusive, violating the biocriteria standard) 82% of the time. When the ADEQ-IBI was applied to both the ADEQ and EMAP taxa lists, the resulting IBI scores were significantly correlated (r=0.91), even though only 4 of the 7 metrics in the IBI were significantly correlated. The IBI scores from both methods were significantly correlated to the percent of riffle habitat, even though the average percent riffle habitat was only 30% of the stream reach. Multivariate analyses found that the percent riffle was an important

  4. Silverton folio, Colorado

    Science.gov (United States)

    Cross, Whitman; Howe, Ernest; Ransome, F. L.

    1905-01-01

    The term San Juan region, or simply "the San Juan," used with variable meaning by early explorers, and naturally with indefinite limitation during the period of settlement, is now quite generally applied to a large tract of mountainous country in southwestern Colorado, together with an undefined zone of lower country bordering it on the north, west, and south.  The Continental Divide traverses this area in a great bow.  The principal part of the district is a deeply scored volcanic plateau, more than 3000 square miles in extent, drained on the north by the tributaties of the Gunnison River, on the west by those of the Dolores and San Miguel rivers, on the south by numerous branches of the San Juan, and on the east by the Rio Grande.  ALl but the latter drainage finds its way to the Gulf of California through the Colorado River.

  5. Effects of organic wastes on water quality from processing of oil shale from the Green River Formation, Colorado, Utah, and Wyoming

    Science.gov (United States)

    Leenheer, J.A.; Noyes, T.I.

    1986-01-01

    A series of investigations were conducted during a 6-year research project to determine the nature and effects of organic wastes from processing of Green River Formation oil shale on water quality. Fifty percent of the organic compounds in two retort wastewaters were identified as various aromatic amines, mono- and dicarboxylic acids phenols, amides, alcohols, ketones, nitriles, and hydroxypyridines. Spent shales with carbonaceous coatings were found to have good sorbent properties for organic constituents of retort wastewaters. However, soils sampled adjacent to an in situ retort had only fair sorbent properties for organic constituents or retort wastewater, and application of retort wastewater caused disruption of soil structure characteristics and extracted soil organic matter constituents. Microbiological degradation of organic solutes in retort wastewaters was found to occur preferentially in hydrocarbons and fatty acid groups of compounds. Aromatic amines did not degrade and they inhibited bacterial growth where their concentrations were significant. Ammonia, aromatic amines, and thiocyanate persisted in groundwater contaminated by in situ oil shale retorting, but thiosulfate was quantitatively degraded one year after the burn. Thiocyanate was found to be the best conservative tracer for retort water discharged into groundwater. Natural organic solutes, isolated from groundwater in contact with Green River Formation oil shale and from the White River near Rangely, Colorado, were readily distinguished from organic constituents in retort wastewaters by molecular weight and chemical characteristic differences. (USGS)

  6. Alteration Map Showing Major Faults and Veins and Associated Water-Quality Signatures of the Animas River Watershed Headwaters Near Silverton, Southwest Colorado

    Science.gov (United States)

    Bove, Dana J.; Yager, Douglas B.; Mast, M. Alisa; Dalton, J. Brad

    2007-01-01

    This map was produced to provide hard-copy and digital data for alteration assemblages in the historical mining area centered on the Tertiary San Juan and Silverton calderas. The data have direct application to geoenvironmental and mineral exploration objectives. This dataset represents alteration mapping for the upper Animas River watershed near Silverton, Colorado. The map is based on detailed 1:12,000-scale field mapping, X-ray diffraction (XRD) analysis, mineral mapping by remote sensing (AVIRIS) data, and 1:24,000-scale aerial photographic interpretation. Geologic structures were compiled and generalized from multiple published and unpublished sources (Burbank and Luedke, 1964; Steven and others, 1974; Luedke and Burbank 1975a, b; Lipman, 1976; Luedke and Burbank, 1987; Luedke, 1996) (see Index Map). Unpublished mapping of the Ironton quadrangle by D.J. Bove and J.P. Kurtz in 1997-1999 was included.

  7. Frequency-magnitude-area relationships for precipitation and flood discharges derived from Next-Generation Radar (NEXRAD): Example application in the Upper and Lower Colorado River Basins

    Science.gov (United States)

    Orem, C. A.; Pelletier, J. D.

    2012-12-01

    Flood-envelope curves, i.e. plots of measured flood discharges versus contributing area for many drainage basins in a given hydroclimatic region, are useful for constraining the upper limit of possible discharges in that region. Their usefulness, however, is limited by the lack of recurrence interval information. In this study, we show that frequency-magnitude-area (FMA) curves can be constructed for precipitation and flood discharges using Stage III Next-Generation Radar (NEXRAD) precipitation estimates and flow-routing algorithms. These FMA curves constrain extreme flood discharges in drainage basins within a region and also provide recurrence interval information. The methods in this study follow the flood-envelope curve approach in that drainage basins of similar size are grouped and data aggregated into one population. We improve on the flood-envelope curve approach by assigning a recurrence interval and errors to flood magnitudes based on a large population of NEXRAD observations taken over time and space. We demonstrate the application of these methods by quantifying the FMA curves for the Upper and Lower Colorado River Basins. Results show that areally-averaged precipitation rates are power-law functions of drainage basin area for a wide range of recurrence intervals. Regression analyses give an average exponent of approximately 0.77 ± 0.04. FMA curves of flood discharges are not power-law functions of area, but instead exhibit the characteristic concave-down shape of published flood-envelope curves in log-log space. The concave-down shape is due to both hydrodynamic and geomorphic dispersion, but not limitations on the increase in precipitation with increasing area, as evidenced by the power-law relationship between area and precipitation rate. Flood discharges calculated by our method are comparable to, but slightly higher than, those reported in the literature for our study regions, suggesting that previously published flood-envelope curves for these

  8. Colorado Plateaus Ecoregion: Chapter 21 in Status and trends of land change in the Western United States--1973 to 2000

    Science.gov (United States)

    Stier, Michael P.

    2012-01-01

    The Colorado Plateaus Ecoregion covers approximately 129,617 km2 (50,045 mi2) within southern and eastern Utah, western Colorado, and the extreme northern part of Arizona (fig. 1). The terrain of this ecoregion is characterized by broad plateaus, ancient volcanoes, and deeply dissected canyons (Booth and others, 1999; fig. 2). The ecoregion is bounded on the east by the Wyoming Basin and Southern Rockies Ecoregions in Colorado and on the northwest by the Wasatch and Uinta Mountains Ecoregion in northern and central Utah. To the south, the ecoregion borders the Arizona/New Mexico Plateau Ecoregion, which has a higher elevation and more grasslands than the Colorado Plateaus Ecoregion (Omernik, 1987; U.S. Environmental Protection Agency, 1997).

  9. Rawhide Energy Station, Fort Collins, Colorado

    Energy Technology Data Exchange (ETDEWEB)

    Peltier, R.

    2008-10-15

    The staff of Platte River Power Authority's Rawhide Energy Station have been racking up operating stats and an environmental performance record that is the envy of other plant managers. In the past decade Rawhide has enjoyed an equivalent availability factor in the mid to high 90s and an average capacity factor approaching 90%. Still not content with this performance, Rawhide invested in new technology and equipment upgrades to further optimise performance, reduce emissions, and keep cost competitive. The Energy Station includes four GE France 7EA natural gas-fired turbines totalling 260 MW and a 274 MW coal-fired unit located in northeastern Colorado. 7 figs.

  10. On the Edge: the Impact of Climate Change, Climate Extremes, and Climate-driven Disturbances on the Food-Energy-Water Nexus in the Colorado River Basin

    Science.gov (United States)

    Bennett, K. E.; McDowell, N. G.; Tidwell, V. C.; Xu, C.; Solander, K.; Jonko, A. K.; Wilson, C. J.; Middleton, R. S.

    2016-12-01

    The Colorado River Basin (CRB) is a critical watershed in terms of vulnerability to climate change and supporting the food-energy-water nexus. Climate-driven disturbances in the CRB—including wildfire, drought, and pests—threaten the watershed's ability to reliably support a wide array of ecosystem services while meeting the interrelated demands of the food-energy-water nexus. Our work illustrates future changes for upper Colorado River headwater basins using the Variable Infiltration Capacity hydrologic model driven by downscaled CMIP5 global climate data coupled with pseudo-dynamic vegetation shifts associated with changing fire and drought conditions. We examine future simulated streamflow within the context of an operational model framework to consider the impacts on water operators and managers who rely upon the timely and continual delivery of streamflow. We focus on results for a large case study basin within the CRB—the San Juan River—showing future scenarios where this ecosystem is pushed towards the extremes. Our findings illustrate that landscape change in the CRB cause delayed snowmelt and increased evapotranspiration from shrublands, which leads to increases in the frequency and magnitude of both droughts and floods within disturbed systems. By 2080, coupled climate and landscape change produces a dramatically altered hydrograph resulting in larger peak flows, reduced lower flows, and lower overall streamflow. Operationally, this results in increased future water delivery challenges and lower reservoir storages driven by changes in the headwater basins. Ultimately, our work shows that the already-stressed CRB ecosystem could, in the future, be pushed over a tipping point, significantly impacting the basin's ability to reliably supply water for food, energy, and urban uses.

  11. Chapter A. Effects of urbanization on stream ecosystems in the South Platte River basin, Colorado and Wyoming

    Science.gov (United States)

    Sprague, Lori A.; Zuellig, Robert E.; Dupree, Jean A.

    2006-01-01

    This report describes the effects of urbanization on physical, chemical, and biological characteristics of stream ecosystems in 28 basins along an urban land-use gradient in the South Platte River Basin, Colorado and Wyoming, from 2002 through 2003. Study basins were chosen to minimize natural variability among basins due to factors such as geology, elevation, and climate and to maximize coverage of different stages of urban development among basins. Because land use or population density alone often are not a complete measure of urbanization, land use, land cover, infrastructure, and socioeconomic variables were integrated in a multimetric urban intensity index to represent the degree of urban development in each study basin. Physical characteristics studied included stream hydrology, stream temperature, and habitat; chemical characteristics studied included nutrients, pesticides, suspended sediment, sulfate, chloride, and fecal bacteria concentrations; and biological characteristics studied included algae, fish, and invertebrate communities. Semipermeable membrane devices (SPMDs), passive samplers that concentrate trace levels of hydrophobic organic contaminants like polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), also were used. The objectives of the study were to (1) examine physical, chemical, and biological responses along the gradient of urbanization; (2) determine the major physical, chemical, and landscape variables affecting the structure of aquatic communities; and (3) evaluate the relevance of the results to the management of water resources in the South Platte River Basin. Commonly observed effects of urbanization on instream physical, chemical, and biological characteristics, such as increased flashiness, higher magnitude and more frequent peak flows, increased concentrations of chemicals, and changes in aquatic community structure, generally were not observed in this study. None of the hydrologic, temperature, habitat

  12. Summary report of responses of key resources to the 2000 Low Steady Summer Flow experiment, along the Colorado River downstream from Glen Canyon Dam, Arizona

    Science.gov (United States)

    Ralston, Barbara E.

    2011-01-01

    In the spring and summer of 2000, a series of steady discharges of water from Glen Canyon Dam on the Colorado River were used to evaluate the effects of aquatic habitat stability and water temperatures on native fish growth and survival, with a special focus on the endangered humpback chub (Gila cypha), downstream from the dam in Grand Canyon. The steady releases were bracketed by peak powerplant releases in late-May and early-September. The duration and volume of releases from the dam varied between spring and summer. The intent of the experimental hydrograph was to mimic predam river discharge patterns by including a high, steady discharge in the spring and a low, steady discharge in the summer. The hydrologic experiment was called the Low Steady Summer Flow (LSSF) experiment because steady discharges of 226 m3/s dominated the hydrograph for 4 months from June through September 2000. The experimental hydrograph was developed in response to one of the U.S. Fish and Wildlife Service's Recommended and Prudent Alternatives (RPA) in its Biological Opinion of the Operation of Glen Canyon Dam Final Environmental Impact Statement. The RPA focused on the hypothesis that seasonally adjusted steady flows were dam operations that might benefit humpback chub more than the Record of Decision operations, known as Modified Low Fluctuating Flow (MLFF) operations. Condensed timelines between planning and implementation (2 months) of the experiment and the time required for logistics, purchasing, and contracting resulted in limited data collection during the high-release part of the experiment that occurred in spring. The LSSF experiment is the longest planned hydrograph that departed from the MLFF operations since Record of Decision operations began in 1996. As part of the experiment, several studies focused on the responses of physical properties related to environments that young-of-year (YOY) native fish might occupy (for example, measuring mainstem and shoreline water

  13. A multimodel ensemble approach to assessment of climate change impacts on the hydrology and water resources of the Colorado River basin

    Directory of Open Access Journals (Sweden)

    N. Christensen

    2006-12-01

    Full Text Available Implications of 21st century climate change on the hydrology and water resources of the Colorado River basin were assessed using a multimodel ensemble approach in which downscaled and bias corrected output from 11 General Circulation Models (GCMs was used to drive macroscale hydrology and water resources models. Downscaled climate scenarios (ensembles were used as forcings to the Variable Infiltration Capacity (VIC macroscale hydrology model, which in turn forced the Colorado River Reservoir Model (CRMM. Ensembles of downscaled precipitation and temperature, and derived streamflows and reservoir system performance were assessed through comparison with current climate simulations for the 1950–1999 historical period. For each of the 11 GCMs, two emissions scenarios (IPCC SRES A2 and B1, corresponding to relatively unconstrained growth in emissions, and elimination of global emissions increases by 2100 were represented. Results for the A2 and B1 climate scenarios were divided into period 1 (2010–2039, period 2 (2040–2069, and period 3 (2070–2099. The mean temperature change averaged over the 11 ensembles for the Colorado basin for the A2 emission scenario ranged from 1.2 to 4.4°C for periods 1–3, and for the B1 scenario from 1.3 to 2.7°C. Precipitation changes were modest, with ensemble mean changes ranging from −1 to −2 percent for the A2 scenario, and from +1 to −1 percent for the B1 scenario. An analysis of seasonal precipitation patterns showed that most GCMs had modest reductions in summer precipitation and increases in winter precipitation. Derived 1 April snow water equivalent declined for all ensemble members and time periods, with maximum (ensemble mean reductions of 38 percent for the A2 scenario in period 3. Runoff changes were mostly the result of a dominance of increased evapotranspiration over the seasonal precipitation shifts, with ensemble mean runoff reductions of −1, −6, and −11 percent for the A2 ensembles

  14. Four-band image mosaic of the Colorado River corridor downstream of Glen Canyon Dam in Arizona, derived from the May 2013 airborne image acquisition

    Science.gov (United States)

    Durning, Laura E.; Sankey, Joel B.; Davis, Philip A.; Sankey, Temuulen T.

    2016-12-14

    In May 2013, the U.S. Geological Survey’s Grand Canyon Monitoring and Research Center acquired airborne multispectral high-resolution data for the Colorado River in the Grand Canyon, Arizona. The image data, which consist of four color bands (blue, green, red, and near-infrared) with a ground resolution of 20 centimeters, are available to the public as 16-bit geotiff files at http://dx.doi.org/10.5066/F7TX3CHS. The images are projected in the State Plane map projection, using the central Arizona zone (202) and the North American Datum of 1983. The assessed accuracy for these data is based on 91 ground-control points and is reported at the 95-percent confidence level as 0.64 meter (m) and a root mean square error of 0.36 m. The primary intended uses of this dataset are for maps to support field data collection and simple river navigation; high-spatial-resolution change detection of sandbars, other geomorphic landforms, riparian vegetation, and backwater and nearshore habitats; and other ecosystem-wide mapping.

  15. Cross-section geometry and sediment-size distribution data from Muddy Creek and North Fork Gunnison River below Paonia Reservoir, Colorado, 2016

    Science.gov (United States)

    Henneberg, Mark; Richards, Rodney J.; Williams, Cory A.

    2017-01-01

    This data set contains cross-section geometry and sediment-size distribution data collected in the fall of 2016 from Muddy Creek and North Fork Gunnison River below Paonia Reservoir, Colorado. Six cross-sections were surveyed using Real-Time Kinematic Global Navigation Satellite System (RTK-GNSS) methods to document channel geometry below the reservoir in 2015. Those same cross-sections were re-surveyed using the same methods in 2016 to document any changes. One cross-section was surveyed on Muddy Creek below Paonia Reservoir, and five cross-sections were surveyed from North Fork Gunnison River below Paonia Reservoir. All six cross-sections are incorporated in this data release within one shapefile. Pebble-counts were performed at each of the six cross-sections to document sediment-size distributions downstream from the reservoir. Four transects were located in the vicinity of each cross-section, where sediment size was measured and recorded. Transect locations were based on bankfull channel width; with transect 1 located one bankfull channel width upstream from the surveyed cross-section, transect 2 at the surveyed cross-section, and transects 3 and 4 located one and two bankfull channel widths downstream from the surveyed cross-section, respectively. All of the sediment-size distribution data are presented in .CSV files, with one file for each cross-section location incorporating all of the data for each of the four transects at that location.

  16. Cross-Section Geometry and Sediment-Size Distribution Data from Muddy Creek and North Fork Gunnison River below Paonia Reservoir, Colorado, 2015

    Science.gov (United States)

    Henneberg, Mark; Richards, Rodney J.; Williams, Cory A.

    2017-01-01

    This data set contains cross-section geometry and sediment-size distribution data collected in the fall of 2015 from Muddy Creek and North Fork Gunnison River below Paonia Reservoir, Colorado. Six cross-sections were surveyed using Real-Time Kinematic Global Navigation Satellite System (RTK-GNSS) methods to document channel geometry below the reservoir. One cross-section was surveyed on Muddy Creek below Paonia Reservoir, and five cross-sections were surveyed from North Fork Gunnison River below Paonia Reservoir. All six cross-sections are incorporated in this data release within one shapefile. Pebble-counts were performed at each of the six cross-sections to document sediment-size distributions downstream from the reservoir. Four transects were located in the vicinity of each cross-section, where sediment size was measured and recorded. Transect locations were based on bankfull channel width; with transect 1 located one bankfull channel width upstream from the surveyed cross-section, transect 2 at the surveyed cross-section, and transects 3 and 4 located one and two bankfull channel widths downstream from the surveyed cross-section, respectively. All of the sediment-size distribution data are presented in .CSV files, with one file for each cross-section location incorporating all of the data for each of the four transects at that location.

  17. Growth of plutons by incremental emplacement of sheets in crystal-rich host: Evidence from Miocene intrusions of the Colorado River region, Nevada, USA

    Science.gov (United States)

    Miller, C.F.; Furbish, D.J.; Walker, B.A.; Claiborne, L.L.; Koteas, G.C.; Bleick, H.A.; Miller, J.S.

    2011-01-01

    Growing evidence supports the notion that plutons are constructed incrementally, commonly over long periods of time, yet field evidence for the multiple injections that seem to be required is commonly sparse or absent. Timescales of up to several million years, among other arguments, indicate that the dominant volume does not remain largely molten, yet if growing plutons are constructed from rapidly solidifying increments it is unlikely that intrusive contacts would escape notice. A model wherein magma increments are emplaced into melt-bearing but crystal-rich host, rather than either solid or crystal-poor material, provides a plausible explanation for this apparent conundrum. A partially solidified intrusion undoubtedly comprises zones with contrasting melt fraction and therefore strength. Depending on whether these zones behave elastically or ductilely in response to dike emplacement, intruding magma may spread to form sheets by either of two mechanisms. If the melt-bearing host is elastic on the relevant timescale, magma spreads rather than continuing to propagate upward, where it encounters a zone of higher rigidity (higher crystal fraction). Similarly, if the dike at first ascends through rigid, melt-poor material and then encounters a zone that is weak enough (poor enough in crystals) to respond ductilely, the ascending material will also spread because the dike tip ceases to propagate as in rigid material. We propose that ascending magma is thus in essence trapped, by either mechanism, within relatively crystal-poor zones. Contacts will commonly be obscure from the start because the contrast between intruding material (crystal-poorer magma) and host (crystal-richer material) is subtle, and they may be obscured even further by subsequent destabilization of the crystal-melt framework. Field evidence and zircon zoning stratigraphy in plutons of the Colorado River region of southern Nevada support the hypothesis that emplacement of magma replenishments into a

  18. Thickness of the Upper Hell Creek hydrogeologic unit in the Powder River structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the thickness, in feet, of the Upper Hell Creek hydrogeologic unit in the Powder River basin. The data are presented as ASCII text files that...

  19. EAARL-B Topography-Big Thicket National Preserve: Lower Neches River Corridor Unit, Texas, 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A first-surface topography Digital Surface Model (DSM) mosaic for the Lower Neches River Corridor Unit of Big Thicket National Preserve in Texas was produced from...

  20. Thickness of the middle Fort Union hydrogeologic unit in the Powder River structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the thickness, in feet, of the middle Fort Union hydrogeologic unit in the Powder River basin. The data are presented as ASCII text files that...

  1. Tallahatchie NWR and Black Bayou Unit (Coldwater River NWR) Bird Observations 1996

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Anecdotal bird observations from Tallahatchie NWR, the Black Bayou Unit (Coldwater River NWR) surrounding areas throughout 1996 were recorded by the refuge biologist...

  2. Tallahatchie NWR and Black Bayou Unit (Coldwater River NWR) Bird Observations 1998

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Anecdotal bird observations from Tallahatchie NWR, the Black Bayou Unit (Coldwater River NWR) and surrounding areas throughout 1998 were recorded by the refuge...

  3. Tallahatchie NWR and Black Bayou Unit (Coldwater River NWR) Bird Observations 1997

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Anecdotal bird observations from Tallahatchie NWR, the Black Bayou Unit (Coldwater River NWR) surrounding areas throughout 1997 were recorded by the refuge biologist...

  4. Change in the Magnitude of River Flooding in the United States, 1965-2015

    Data.gov (United States)

    U.S. Environmental Protection Agency — This figure shows changes in the size and frequency of flooding events in rivers and streams in the United States between 1965 and 2015. Blue upward-pointing symbols...

  5. EAARL-B Topography-Big Thicket National Preserve: Lower Neches River Corridor Unit, Texas, 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A first-surface topography Digital Surface Model (DSM) mosaic for the Lower Neches River Corridor Unit of Big Thicket National Preserve in Texas was produced from...

  6. Comparative Analysis Of River Conservation In The United States And South Africa

    Science.gov (United States)

    Both the United States and South Africa are recognized for their strong and innovative approaches to the conservation of river ecosystems. These national programs possess similar driving legislation and ecoregional classification schemes supported by comprehensive monitoring prog...

  7. Altitude of the top of the basal confining unit in the Powder River structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the altitude, in feet above North American Vertical Datum of 1988 (NAVD88), of the basal confining unit in the Powder River basin. The data are...

  8. EAARL-B Topography-Big Thicket National Preserve: Lower Neches River Corridor Unit, Texas, 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare-earth topography Digital Elevation Model (DEM) mosaic for the Lower Neches River Corridor Unit of Big Thicket National Preserve in Texas was produced from...

  9. EAARL-B Topography-Big Thicket National Preserve: Lower Neches River Corridor Unit, Texas, 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare-earth topography Digital Elevation Model (DEM) mosaic for the Lower Neches River Corridor Unit of Big Thicket National Preserve in Texas was produced from...

  10. Does damming of the Colorado River affect the nursery area of blue shrimp Litopenaeus stylirostris (Decapoda: Penaeidae in the Upper Gulf of California?

    Directory of Open Access Journals (Sweden)

    Eugenio Alberto Aragón-Noriega

    2000-12-01

    Full Text Available After damming the Colorado River the freshwater flow was reduced to 1 % of its virgin flow to the Upper Gulf of California (UGC. The ecological effects need to be properly documented. The UGC is the nursery area for Litopenaeus stylirostris, the most profitable fishery in the zone. In order to know the relative abundance of L. stylirostris postlarval stage we conducted a sampled survey every 14 days in 1993, 1994 and 1997, plus an intensive sampling during a complete tide cycle in July 1995 and 1996. We did 10 min trawls each hour during the flood tide. Relative abundance of postlarvae was higher (pEl represamiento del Río Colorado ha ocasionado que el flujo de agua dulce sobre el Alto Golfo de California (AGC se haya reducido hasta el 1 % del flujo original. Se ha documentado el efecto de la reducción de agua dulce sobre las condiciones hidrográficas del AGC, pero las repercusiones ecológicas no se han descrito apropiadamente. El AGC ha sido área de crianza para especies comerciales como el camarón Litopenaeus stylirostris. Se hicieron recolectas de postlarvas de L. stylirostris en el AGC durante cinco años consecutivos. Los muestreos fueron catorcenalmente en los años de 1993, 1994 y 1997 y se realizó una recolecta diaria durante 15 días consecutivos en los años 1995 y 1996. Para ello se arrastró una red de plancton de 505 µ durante 10 min cada hora durante el flujo de marea. La abundancia relativa de las postlarvas de camarón en esta zona viaria considerablemente en años cuando el flujo de agua dulce incrementa. La abundancia es mayor hasta en un 200 % (p < 0.05 cuando existe descarga de agua dulce al AGC.

  11. Examination of the potential impacts of dust and pollution aerosol acting as cloud nucleating aerosol on water resources in the Colorado River Basin

    Science.gov (United States)

    Jha, Vandana

    In this study we examine the cumulative effect of dust acting as cloud nucleating aerosol (cloud condensation nuclei (CCN), giant cloud condensation nuclei (GCCN), and ice nuclei (IN)) along with anthropogenic aerosol pollution acting primarily as CCN, over the entire Colorado Rocky Mountains from the months of October to April in the year 2004-2005; the snow year. This ˜6.5 months analysis provides a range of snowfall totals and variability in dust and anthropogenic aerosol pollution. The specific objectives of this research is to quantify the impacts of both dust and pollution aerosols on wintertime precipitation in the Colorado Mountains using the Regional Atmospheric Modeling System (RAMS). In general, dust enhances precipitation primarily by acting as IN, while aerosol pollution reduces water resources in the CRB via the so-called "spill-over" effect, by enhancing cloud droplet concentrations and reducing riming rates. Dust is more episodic and aerosol pollution is more pervasive throughout the winter season. Combined response to dust and aerosol pollution is a net reduction of water resources in the CRB. The question is by how much are those water resources affected? Our best estimate is that total winter-season precipitation loss for for the CRB the 2004-2005 winter season due to the combined influence of aerosol pollution and dust is 5,380,00 acre-feet of water. Sensitivity studies for different cases have also been run for the specific cases in 2004-2005 winter season to analyze the impact of changing dust and aerosol ratios on precipitation in the Colorado River Basin. The dust is varied from 3 to 10 times in the experiments and the response is found to be non monotonic and depends on various environmental factors. The sensitivity studies show that adding dust in a wet system increases precipitation when IN affects are dominant. For a relatively dry system high concentrations of dust can result in over-seeding the clouds and reductions in precipitation

  12. Boundary of the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This vector data set delineates the approximate boundary of the Eagle River watershed valley-fill aquifer (ERWVFA). This data set was developed by a cooperative...

  13. An integrated geological and geophysical study of the Uinta Mountains, Utah, Colorado and a geophysical study on Tamarix in the Rio Grande River basin, West Texas

    Science.gov (United States)

    Khatun, Salma

    2008-07-01

    This research consists of two parts. One part deals with an integrated analysis of the structural anomaly associated with the Uinta Mountains, Utah. The other part deals with a study on the effect of Tamarix on soil and water quality. The Uinta Mountains are an anomalous east-west trending range of the Central Rocky Mountains and are located in northeastern Utah and northwestern Colorado. They have long been recognized as a structural anomaly that is surrounded by other Laramide structures that trend N-S or northwest. The study area extends from -112 to -108 degrees longitude and 41.5 to 39 degrees latitude and consists of three major geologic features: The Green River basin, Uinta Mountains, and the Uinta basin. This study investigates the tectonic evolution and the structural development of the Uinta aulacogen. There is a growing interest in exploration for petroleum and other hydrocarbons in the area of this study. Oil companies have been drilling wells in this area since the 1950's. The results of this study will enhance the existing knowledge of this region, and thus will help in the pursuit of hydrocarbons. A highly integrated approach was followed for this investigation. Gravity, magnetic, drill hole, seismic and receiver function data were used in the analysis. Gravity and magnetic data were analyzed using software tools available in the Department of Geological Sciences such as Oasis Montaj and GIS. Filtered gravity maps show that the Uinta Mountains and the surrounding basins and uplifts are deep seated features. These maps also reveal a correlation between the Uinta Mountains and the regional tectonic structures. This correlation helps in understanding how the different tectonic events that this region went through contributed to the different phases of development of the Uinta aulacogen. Four gravity models were generated along four north-south trending profile lines covering the target area from east to west. Interpretations of these models give a

  14. Thomas Edison State College and Colorado State University: Using Cutting-Edge Technology to Enhance CE Unit Success

    Science.gov (United States)

    van Zyl, Henry; Powell, Albert, Jr.

    2012-01-01

    Thomas Edison State College (TESC) and Colorado State University (CSU) offer significant contrasts in institutional culture, student demographics, faculty and institutional priorities and approaches to distance education course development and delivery. This article offers case studies showing that widely disparate program design and delivery…

  15. 78 FR 14842 - Crystal River Nuclear Generating Plant, Unit 3; Application for Renewal of License to Facility...

    Science.gov (United States)

    2013-03-07

    ... COMMISSION Crystal River Nuclear Generating Plant, Unit 3; Application for Renewal of License to Facility... operate the Crystal River Nuclear Generating Plant, Unit 3 (CR3), at 2609 megawatts thermal. The FPC... located near Crystal River, FL; the current operating license for the CR3 expires on December 3, 2016. The...

  16. Characterization of geomorphic units in the alluvial valleys and channels of Gulf Coastal Plain rivers in Texas, with examples from the Brazos, Sabine, and Trinity Rivers, 2010

    Science.gov (United States)

    Coffman, David K.; Malstaff, Greg; Heitmuller, Franklin T.

    2011-01-01

    The U.S. Geological Survey, in cooperation with the Texas Water Development Board, described and characterized examples of geomorphic units within the channels and alluvial valleys of Texas Gulf Coastal Plain rivers using a geomorphic unit classification scale that differentiates geomorphic units on the basis of their location either outside or inside the river channel. The geomorphic properties of a river system determine the distribution and type of potential habitat both within and adjacent to the channel. This report characterizes the geomorphic units contained in the river channels and alluvial valleys of Texas Gulf Coastal Plain rivers in the context of the River Styles framework. This report is intended to help Texas Instream Flow Program practitioners, river managers, ecologists and biologists, and others interested in the geomorphology and the physical processes of the rivers of the Texas Gulf Coastal Plain (1) gain insights into how geomorphic units develop and adjust spatially and temporally, and (2) be able to recognize common geomorphic units from the examples cataloged in this report. Recent aerial imagery (high-resolution digital orthoimagery) collected in 2008 and 2009 were inspected by using geographic information system software to identify representative examples of the types of geomorphic units that occurred in the study area. Geomorphic units outside the channels of Texas Gulf Coastal Plain rivers are called \\"valley geomorphic units\\" in this report. Valley geomorphic units for the Texas Gulf Coastal Plain rivers described in this report are terraces, flood plains, crevasses and crevasse splays, flood-plain depressions, tie channels, tributaries, paleochannels, anabranches, distributaries, natural levees, neck cutoffs, oxbow lakes, and constructed channels. Channel geomorphic units occur in the river channel and are subject to frequent stresses associated with flowing water and sediment transport; they adjust (change) relatively quickly in

  17. Effects of increased discharge on spawning and age-0 recruitment of rainbow trout in the Colorado River at Lees Ferry, Arizona

    Science.gov (United States)

    Avery, Luke A.; Korman, Josh; Persons, William R.

    2015-01-01

    Negative interactions of Rainbow Trout Oncorhynchus mykiss with endangered Humpback Chub Gila cypha pose challenges to the operation of Glen Canyon Dam (GCD) to manage for both species in the Colorado River. Operations to enhance the Rainbow Trout tailwater fishery may lead to an increase in downstream movement of the trout to areas where they are likely to interact with Humpback Chub. We evaluated the effects of dam operations on age-0 Rainbow Trout in the tailwater fishery to inform managers about how GCD operations could benefit a tailwater fishery for Rainbow Trout; although this could affect a Humpback Chub population farther downstream. A near year-long increase in discharge at GCD in 2011 enabled us to evaluate whether high and stable flows led to increased spawning and production of age-0 Rainbow Trout compared with other years. Rainbow Trout spawning was monitored by fitting a model to observed redd counts to estimate the number of redds created over a spawning season. Data collected during electrofishing trips in July–September and November were used to acquire age-0 trout population and mortality rate estimates. We found that high and stable flows in 2011 resulted in 3,062 redds (1.7 times the mean of all survey years) and a population estimate of 686,000 age-0 Rainbow Trout (second highest on record). Despite high initial abundance, mortality remained low through the year (0.0043%/d) resulting in significant recruitment with a record high November population estimate of 214,000 age-0 Rainbow Trout. Recent monitoring indicates this recruitment event was followed by an increase in downstream migration, which may lead to increased interactions with downstream populations of Humpback Chub. Consequently, while our results indicate that manipulating flow at GCD can be used to manage Rainbow Trout spawning and recruitment, fisheries managers should use flow manipulation in moderation to minimize downstream migration in order to reduce negative

  18. Uranium Bio-accumulation and Cycling as revealed by Uranium Isotopes in Naturally Reduced Sediments from the Upper Colorado River Basin

    Science.gov (United States)

    Lefebvre, Pierre; Noël, Vincent; Jemison, Noah; Weaver, Karrie; Bargar, John; Maher, Kate

    2016-04-01

    Uranium (U) groundwater contamination following oxidized U(VI) releases from weathering of mine tailings is a major concern at numerous sites across the Upper Colorado River Basin (CRB), USA. Uranium(IV)-bearing solids accumulated within naturally reduced zones (NRZs) characterized by elevated organic carbon and iron sulfide compounds. Subsequent re-oxidation of U(IV)solid to U(VI)aqueous then controls the release to groundwater and surface water, resulting in plume persistence and raising public health concerns. Thus, understanding the extent of uranium oxidation and reduction within NRZs is critical for assessing the persistence of the groundwater contamination. In this study, we measured solid-phase uranium isotope fractionation (δ238/235U) of sedimentary core samples from four study sites (Shiprock, NM, Grand Junction, Rifle and Naturita, CO) using a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS). We observe a strong correlation between U accumulation and the extent of isotopic fractionation, with Δ238U up to +1.8 ‰ between uranium-enriched and low concentration zones. The enrichment in the heavy isotopes within the NRZs appears to be especially important in the vadose zone, which is subject to variations in water table depth. According to previous studies, this isotopic signature is consistent with biotic reduction processes associated with metal-reducing bacteria. Positive correlations between the amount of iron sulfides and the accumulation of reduced uranium underline the importance of sulfate-reducing conditions for U(IV) retention. Furthermore, the positive fractionation associated with U reduction observed across all sites despite some variations in magnitude due to site characteristics, shows a regional trend across the Colorado River Basin. The maximum extent of 238U enrichment observed in the NRZ proximal to the water table further suggests that the redox cycling of uranium, with net release of U(VI) to the groundwater by

  19. Simulating Spawning and Juvenile Rainbow Trout (Oncorhynchus mykiss Habitat in Colorado River Based on High-Flow Effects

    Directory of Open Access Journals (Sweden)

    Weiwei Yao

    2017-02-01

    Full Text Available High flow generates significant alterations in downstream river reaches, resulting in physical condition changes in the downstream regions of the river such as water depth, flow velocity, water temperature and river bed. These alterations will lead to change in fish habitat configuration in the river. This paper proposes a model system to evaluate the high flow effects on river velocity, water depth, substrates changes, temperature distribution and consequently assess the change in spawning and juvenile rainbow trout (Oncorhynchus mykiss habitats in the downstream region of the Glen Canyon Dam. Firstly, based on the 2 dimensional (2D depth-averaged CFD (Computational Fluid Dynamics model and heat transfer equation applied for simulation, three indices were simulated, namely depth, flow velocity and temperature distribution. Then, the spawning and juvenile fish preference curves were obtained based on these three indices and substrates distribution. After that, the habitat model was proposed and used to simulate the high flow effects on juvenile and spawning rainbow trout habitat structure. Finally, the weighted usable area (WUA and overall suitability index (OSI of the spawning and juvenile fish species were quantitatively simulated to estimate the habitat sensitivity. The results illustrate that the high flow effect (HFE increased the juvenile rainbow trout habitat quality but decreased the spawning rainbow trout habitat quality. The juvenile trout were mainly affected by the water depth while the spawning rainbow trout were dominated by the bed elevation.

  20. Interim report on the scientific investigations in the Animas River watershed, Colorado to facilitate remediation decisions by the U.S. Bureau of Land Management and the U.S. Forest Service, March 29, 2000 meeting, Denver, Colorado

    Science.gov (United States)

    ,

    2000-01-01

    presumed to be impacted by historical mining activities. The Animas River watershed (fig. 1) was selected by the State and Federal agencies as one of two watersheds in the U.S. to be studied in detail by the USGS in the AML Initiative. Beginning in October 1997, each of the four Divisions of the USGS (Water Resources, Geologic, Biological Resources, and National Mapping) initiated a collaborative integrated science study of the watershed. Funds were provided from USGS base funding to each of the four Divisions in response to the priorities set by Congressional action and within the flexibility provided by the budgetary framework funding individual research programs. The AML Initiative provides for a five-year focused scientific effort in the two watersheds with final synthesis of the scientific results from each to be published in 2001. Publications are released on the AML web site on a regular basis (http://amli.usgs.gov/amli). On March 29, 2000, the USGS hosted a meeting for the BLM and USFS to discuss remediation options that were under consideration for the summer of 2000. The purpose of this report is to provide an overview of the scientific rational provided by the USGS to meet objective one above, and to summarize our preliminary interpretations of our data. Additional information from sites on private lands have been collected by the State of Colorado, EPA, and the ARSG. Unfortunately, these data have not been fully supplied to the USGS so our conclusions are based only upon our data. These interpretations provide science-based constraints on possible remediation options to be considered by the FLMA, the State, and local property owners in the Animas River watershed. The report is presented in outline format to facilitate discussion of remediation options at the March 29, 2000 meeting. Not all historical mining sites within the watershed are on public lands. This should not be construed to be a final report of the USGS

  1. Spatial and stratigraphic distribution of water in oil shale of the Green River Formation using Fischer assay, Piceance Basin, northwestern Colorado

    Science.gov (United States)

    Johnson, Ronald C.; Mercier, Tracey J.; Brownfield, Michael E.

    2014-01-01

    The spatial and stratigraphic distribution of water in oil shale of the Eocene Green River Formation in the Piceance Basin of northwestern Colorado was studied in detail using some 321,000 Fischer assay analyses in the U.S. Geological Survey oil-shale database. The oil-shale section was subdivided into 17 roughly time-stratigraphic intervals, and the distribution of water in each interval was assessed separately. This study was conducted in part to determine whether water produced during retorting of oil shale could provide a significant amount of the water needed for an oil-shale industry. Recent estimates of water requirements vary from 1 to 10 barrels of water per barrel of oil produced, depending on the type of retort process used. Sources of water in Green River oil shale include (1) free water within clay minerals; (2) water from the hydrated minerals nahcolite (NaHCO3), dawsonite (NaAl(OH)2CO3), and analcime (NaAlSi2O6.H20); and (3) minor water produced from the breakdown of organic matter in oil shale during retorting. The amounts represented by each of these sources vary both stratigraphically and areally within the basin. Clay is the most important source of water in the lower part of the oil-shale interval and in many basin-margin areas. Nahcolite and dawsonite are the dominant sources of water in the oil-shale and saline-mineral depocenter, and analcime is important in the upper part of the formation. Organic matter does not appear to be a major source of water. The ratio of water to oil generated with retorting is significantly less than 1:1 for most areas of the basin and for most stratigraphic intervals; thus water within oil shale can provide only a fraction of the water needed for an oil-shale industry.

  2. Characterization of mean transit time at large springs in the Upper Colorado River Basin, USA: a tool for assessing groundwater discharge vulnerability

    Science.gov (United States)

    Solder, John E.; Stolp, Bernard J.; Heilweil, Victor M.; Susong, David D.

    2016-12-01

    Environmental tracers (noble gases, tritium, industrial gases, stable isotopes, and radio-carbon) and hydrogeology were interpreted to determine groundwater transit-time distribution and calculate mean transit time (MTT) with lumped parameter modeling at 19 large springs distributed throughout the Upper Colorado River Basin (UCRB), USA. The predictive value of the MTT to evaluate the pattern and timing of groundwater response to hydraulic stress (i.e., vulnerability) is examined by a statistical analysis of MTT, historical spring discharge records, and the Palmer Hydrological Drought Index. MTTs of the springs range from 10 to 15,000 years and 90 % of the cumulative discharge-weighted travel-time distribution falls within the range of 2-10,000 years. Historical variability in discharge was assessed as the ratio of 10-90 % flow-exceedance ( R 10/90%) and ranged from 2.8 to 1.1 for select springs with available discharge data. The lag-time (i.e., delay in discharge response to drought conditions) was determined by cross-correlation analysis and ranged from 0.5 to 6 years for the same select springs. Springs with shorter MTTs (groundwater response. Results indicate that groundwater discharge to streams in the UCRB will likely respond on the order of years to climate variation and increasing groundwater withdrawals.

  3. Gully annealing by aeolian sediment: field and remote-sensing investigation of aeolian-hillslope-fluvial interactions, Colorado River corridor, Arizona, USA

    Science.gov (United States)

    Sankey, Joel B.; Draut, Amy E.

    2014-01-01

    Processes contributing to development of ephemeral gully channels are of great importance to landscapes worldwide, and particularly in dryland regions where soil loss and land degradation from gully erosion pose long-term land-management problems. Whereas gully formation has been relatively well studied, much less is known of the processes that anneal gullies and impede their growth. This study of gully annealing by aeolian sediment, spanning 95 km along the Colorado River corridor in Glen, Marble, and Grand Canyon, Arizona, USA, employed field and remote sensing observations, including digital topographic modelling. Results indicate that aeolian sediment activity can be locally effective at counteracting gully erosion. Gullies are less prevalent in areas where surficial sediment undergoes active aeolian transport, and have a greater tendency to terminate in active aeolian sand. Although not common, examples exist in the record of historical imagery of gullies that underwent infilling by aeolian sediment in past decades and evidently were effectively annealed. We thus provide new evidence for a potentially important interaction of aeolian–hillslope–fluvial processes, which could affect dryland regions substantially in ways not widely recognized. Moreover, because the biologic soil crust plays an important role in determining aeolian sand activity, and so in turn the extent of gully development, this study highlights a critical role of geomorphic–ecologic interactions in determining arid-landscape evolution.

  4. Chemical U-Th-Pb Monazite Dating of Deformations versus Pluton Emplacement and the Proterozoic History of the Arkansas River Region,Colorado, USA

    Institute of Scientific and Technical Information of China (English)

    CAO Hui

    2009-01-01

    Five lengthy periods involving multiple phases of cordierite and andalusite growth were revealed by detailed studies of foliation inflection/intersection axes (FIA) preserved in porphyroblasts in schists from the Arkansas River region in Colorado, USA. The regionally consistent character of the succession of five different FIA trends enabled the relative timing of each FIA with respect to the next to be determined. The FIA succession from first to last is: FIA 1 trending W-E, FIA 2 trending SSW-NNE, FIA 3 trending NNW-SSE, FIA 4 trending NW-SE and FIA 5 trending SW-NE. For four of the FIA sets, samples were found containing monazite grains preserved as inclusions. These were dated on an electron microprobe. The ages obtained concur exactly with the FIA succession, with FIA 1 at 1506±15 Ma, FIA 2 at 1467±23 Ma, FIA 3 at 1425±18 Ma, FIA 4 not dated and FIA 5 at 1366±20 Ma.These ages are directly reflected in a succession of plutons in the surrounding region dated by other isotopic approaches, suggesting that deformation, metamorphism and pluton emplacement occurred together episodically, but effectively continuously, for some 140 Ma.

  5. Characterization of mean transit time at large springs in the Upper Colorado River Basin, USA: a tool for assessing groundwater discharge vulnerability

    Science.gov (United States)

    Solder, John E.; Stolp, Bernard J.; Heilweil, Victor M.; Susong, David D.

    2016-07-01

    Environmental tracers (noble gases, tritium, industrial gases, stable isotopes, and radio-carbon) and hydrogeology were interpreted to determine groundwater transit-time distribution and calculate mean transit time (MTT) with lumped parameter modeling at 19 large springs distributed throughout the Upper Colorado River Basin (UCRB), USA. The predictive value of the MTT to evaluate the pattern and timing of groundwater response to hydraulic stress (i.e., vulnerability) is examined by a statistical analysis of MTT, historical spring discharge records, and the Palmer Hydrological Drought Index. MTTs of the springs range from 10 to 15,000 years and 90 % of the cumulative discharge-weighted travel-time distribution falls within the range of 2-10,000 years. Historical variability in discharge was assessed as the ratio of 10-90 % flow-exceedance (R 10/90%) and ranged from 2.8 to 1.1 for select springs with available discharge data. The lag-time (i.e., delay in discharge response to drought conditions) was determined by cross-correlation analysis and ranged from 0.5 to 6 years for the same select springs. Springs with shorter MTTs (<80 years) statistically correlate with larger discharge variations and faster responses to drought, indicating MTT can be used for estimating the relative magnitude and timing of groundwater response. Results indicate that groundwater discharge to streams in the UCRB will likely respond on the order of years to climate variation and increasing groundwater withdrawals.

  6. Detecting Ecosystem Performance Anomalies for Land Management in the Upper Colorado River Basin Using Satellite Observations, Climate Data, and Ecosystem Models

    Directory of Open Access Journals (Sweden)

    Bruce K. Wylie

    2010-07-01

    Full Text Available This study identifies areas with ecosystem performance anomalies (EPA within the Upper Colorado River Basin (UCRB during 2005–2007 using satellite observations, climate data, and ecosystem models. The final EPA maps with 250-m spatial resolution were categorized as normal performance, underperformance, and overperformance (observed performance relative to weather-based predictions at the 90% level of confidence. The EPA maps were validated using “percentage of bare soil” ground observations. The validation results at locations with comparable site potential showed that regions identified as persistently underperforming (overperforming tended to have a higher (lower percentage of bare soil, suggesting that our preliminary EPA maps are reliable and agree with ground-based observations. The 3-year (2005–2007 persistent EPA map from this study provides the first quantitative evaluation of ecosystem performance anomalies within the UCRB and will help the Bureau of Land Management (BLM identify potentially degraded lands. Results from this study can be used as a prototype by BLM and other land managers for making optimal land management decisions.

  7. Correcting acoustic Doppler current profiler discharge measurement bias from moving-bed conditions without global positioning during the 2004 Glen Canyon Dam controlled flood on the Colorado River

    Science.gov (United States)

    Gartner, J.W.; Ganju, N.K.

    2007-01-01

    Discharge measurements were made by acoustic Doppler current profiler at two locations on the Colorado River during the 2004 controlled flood from Glen Canyon Dam, Arizona. Measurement hardware and software have constantly improved from the 1980s such that discharge measurements by acoustic profiling instruments are now routinely made over a wide range of hydrologic conditions. However, measurements made with instruments deployed from moving boats require reliable boat velocity data for accurate measurements of discharge. This is normally accomplished by using special acoustic bottom track pings that sense instrument motion over bottom. While this method is suitable for most conditions, high current flows that produce downstream bed sediment movement create a condition known as moving bed that will bias velocities and discharge to lower than actual values. When this situation exists, one solution is to determine boat velocity with satellite positioning information. Another solution is to use a lower frequency instrument. Discharge measurements made during the 2004 Glen Canyon controlled flood were subject to moving-bed conditions and frequent loss of bottom track. Due to site conditions and equipment availability, the measurements were conducted without benefit of external positioning information or lower frequency instruments. This paper documents and evaluates several techniques used to correct the resulting underestimated discharge measurements. One technique produces discharge values in good agreement with estimates from numerical model and measured hydrographs during the flood. ?? 2007, by the American Society of Limnology and Oceanography, Inc.

  8. Sorption of trace metals to an aluminum precipitate in a stream receiving acid rock-drainage; Snake River, Summit County, Colorado

    Energy Technology Data Exchange (ETDEWEB)

    Munk, L.A.; Faure, G.; Pride, D.E. [Ohio State University, Columbus, OH (United States). Dept. of Geological Sciences; Bigham, J.M. [Ohio State University, Columbus, OH (United States). School of Natural Resources

    2002-07-01

    The quality of water in streams that are contaminated by acid drainage from mines and from the weathering of mineralized rocks improves as the water flows downstream. The purpose of this study was to investigate the geochemical processes that occur in one such stream and to determine the fate of the trace metals that are removed from the water. The stream chosen for this purpose was the Snake River, Summit County, Colorado, which is affected by natural acid rock-drainage (ARD) containing SO{sub 4}, Al, Fe, and various trace elements such as Zn, Cu, Pb, Ni, and others. Most of the Fe in the Snake River is removed from solution by the oxidation of Fe{sup 2+} to Fe{sup 3+} and the subsequent precipitation of Fe-oxyhydroxides that form a massive ferricrete deposit near the springs that feed the river. Further downstream, the Snake River (pH = 3.0) mixes with water from Deer Creek (pH = 7.0) thereby increasing its pH to 6.3 and causing SO{sub 4}-rich precipitates of Al-oxyhydroxide to form. The precipitates and associated organic C complexes sorb trace metals from the water and thus have high concentrations of certain elements, including Zn (540-11,400 ppm), Cu (34-221 ppm), Pb (90-340 ppm), and Ni (11-197 ppm). The concentrations of these elements in the precipitates that coat the streambed rise steeply in the zone of mixing and then decline downstream. The trace element concentrations of the water in the mixing zone at the confluence with Deer Creek decrease by 75% or more and are up to 3 orders of magnitude lower than those of the precipitates. Sorption curves for Zn, Cu, Pb, Ni, and SO{sub 4} were derived by stepwise neutralization of a sample of Snake River water (collected above the confluence with Deer Creek) and indicate that the trace metals are sorbed preferentially with increasing pH in the general order Pb, Cu, Zn, and Ni. Sulfate is removed between pH 4 and 5 to form an Al-hydroxysulfate and/or by sorption to microcrystalline gibbsite. The sorption data

  9. Airborne digital-image data for monitoring the Colorado River corridor below Glen Canyon Dam, Arizona, 2009 - Image-mosaic production and comparison with 2002 and 2005 image mosaics

    Science.gov (United States)

    Davis, Philip A.

    2012-01-01

    Airborne digital-image data were collected for the Arizona part of the Colorado River ecosystem below Glen Canyon Dam in 2009. These four-band image data are similar in wavelength band (blue, green, red, and near infrared) and spatial resolution (20 centimeters) to image collections of the river corridor in 2002 and 2005. These periodic image collections are used by the Grand Canyon Monitoring and Research Center (GCMRC) of the U.S. Geological Survey to monitor the effects of Glen Canyon Dam operations on the downstream ecosystem. The 2009 collection used the latest model of the Leica ADS40 airborne digital sensor (the SH52), which uses a single optic for all four bands and collects and stores band radiance in 12-bits, unlike the image sensors that GCMRC used in 2002 and 2005. This study examined the performance of the SH52 sensor, on the basis of the collected image data, and determined that the SH52 sensor provided superior data relative to the previously employed sensors (that is, an early ADS40 model and Zeiss Imaging's Digital Mapping Camera) in terms of band-image registration, dynamic range, saturation, linearity to ground reflectance, and noise level. The 2009 image data were provided as orthorectified segments of each flightline to constrain the size of the image files; each river segment was covered by 5 to 6 overlapping, linear flightlines. Most flightline images for each river segment had some surface-smear defects and some river segments had cloud shadows, but these two conditions did not generally coincide in the majority of the overlapping flightlines for a particular river segment. Therefore, the final image mosaic for the 450-kilometer (km)-long river corridor required careful selection and editing of numerous flightline segments (a total of 513 segments, each 3.2 km long) to minimize surface defects and cloud shadows. The final image mosaic has a total of only 3 km of surface defects. The final image mosaic for the western end of the corridor has

  10. Institutional Arrangements for River Basin Management: A Case Study of Comparison between the United States and China

    Institute of Scientific and Technical Information of China (English)

    ZHOU Gang-yan

    2007-01-01

    This note compares institutional arrangements for water resources management in two river basins, namely, those of the Susquehanna River in the United States and the Yangtze River in China. The Susquehanna River Basin Commission is composed of the US federal government and the three states of New York, Pennsylvania, and Maryland through which the Susquehanna River passes. Under the authority of the Susquehanna River Basin Compact, the Commission deals with water resources problems throughout its vast drainage area. In contrast, the Changjiang(Yangtze River) Water Resources Commission (CWRC) lacks relative effectiveness in mobilizing provincial governments in transboundary water resources management.

  11. Review Report for Flood Control and Recreational Development, Little Colorado River at Holbrook, Arizona. Volume 2. Technical Appendix.

    Science.gov (United States)

    1980-09-01

    aquifer.. 12. The tributaries and msin stqin of the Little Colorad , River w largely unregulated. Although about 26 dam,’ with an stimated aggregate store...riparian, shadscale scrub, short grass , and Great Basin desert scrub. Except for large trees and shrubs associated with the riparian comunity, grasses and...olive, rabbitbrush, black bush, and snakemeed. Such grasses as blue and black gama, galleta, Indian ricegrass, saltgrcsa, and alkali sacaton are comon

  12. Boundary of the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007

    Science.gov (United States)

    Rupert, Michael G.; Plummer, L. Niel

    2009-01-01

    This vector data set delineates the approximate boundary of the Eagle River watershed valley-fill aquifer (ERWVFA). This data set was developed by a cooperative project between the U.S. Geological Survey, Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority. This project was designed to evaluate potential land-development effects on groundwater and surface-water resources so that informed land-use and water management decisions can be made. The boundary of the ERWVFA was developed by combining information from two data sources. The first data source was a 1:250,000-scale geologic map of the Leadville quadrangle developed by Day and others (1999). The location of Quaternary sediments was used as a first approximation of the ERWVFA. The boundary of the ERWVFA was further refined by overlaying the geologic map with Digital Raster Graphic (DRG) scanned images of 1:24,000 topographic maps (U.S. Geological Survey, 2001). Where appropriate, the boundary of the ERWVFA was remapped to correspond with the edge of the valley-fill aquifer marked by an abrupt change in topography at the edge of the valley floor throughout the Eagle River watershed. The boundary of the ERWVFA more closely resembles a hydrogeomorphic region presented by Rupert (2003, p. 8) because it is based upon general geographic extents of geologic materials and not on an actual aquifer location as would be determined through a rigorous hydrogeologic investigation.

  13. Effects of Flaming Gorge Dam hydropower operations on flow and stage in the Green River, Utah and Colorado

    Energy Technology Data Exchange (ETDEWEB)

    Yin, S.C.L.; Cho, H.E. [Argonne National Lab., IL (United States). Environmental Assessment Div.; McCoy, J.J.; Palmer, S.C. [Western Area Power Administration, Salt Lake City, UT (United States)

    1995-05-01

    This report presents the development of Flaming Gorge Reservoir release patterns and resulting downstream flows and stages for four potential hydropower operational scenarios. The release patterns were developed for three representative hydrologic years: moderate, dry, and wet. Computer models were used to estimate flows and stages in the Green River resulting from these release patterns for the moderate water year. The four hydropower operational scenarios for Flaming Gorge Dam were year-round high fluctuating flows, seasonally adjusted high fluctuating flows, seasonally adjusted moderate fluctuating flows, and seasonally adjusted steady flows. The year-round high fluctuating flow scenario assumes that the monthly total reservoir releases would be the same as historical releases. The remaining seasonally adjusted flow scenarios would comply with the 1992 Biological Opinion of the US Fish and Wildlife Service, which requires high flows in the spring and limited hourly fluctuations, especially in summer and autumn releases, to protect endangered fish. Within one year, the maximum daily river stage fluctuations resulting from hydropower operations under the seasonally adjusted high fluctuating flow scenario would be similar to the maximum daily fluctuations under the year-round high fluctuating flow scenario. However, reduced or no fluctuations would occur in some time periods under the former scenario. The maximum daily river stage fluctuations under the seasonally adjusted moderate fluctuating flow scenario would be about half of those under the seasonally adjusted high fluctuating flow scenario.

  14. Long-term change in perennial vegetation along the Colorado river in Grand Canyon national park (1889-2010)

    Science.gov (United States)

    Webb, R.H.; Belnap, J.; Scott, M.L.; Esque, T.C.

    2011-01-01

    Long-term monitoring data are difficult to obtain for high-value resource areas, particularly in remote parts of national parks. One long-used method for evaluating change uses ground-based repeat photography to match historical images of landscapes. River expeditions that documented a proposed railroad route through Grand Canyon with large-format photographs occurred in 1889 and 1890. A total of 452 images from those expeditions are still in existence, and these were matched as closely as possible from December 1989 through March 1992. In 2010 and 2011, we are repeating these matches 120 years after the originals and 20 years after the first matches. This repeat photography provides visual information that can be interpreted for changes in terrestrial and riparian ecosystems along the river corridor, including change in the desert plant assemblages related to increasing winter low temperatures and severe drought. The riparian ecosystem, which originally consisted of native species established along the stage of frequent floods, has increased in area, density, and biomass as both nonnative and native species have become established following flow regulation by Glen Canyon Dam. The original and matched images provide the basis for one element of a robust monitoring program for the effects of climate change on ecosystem resources.

  15. Field screening of water, soil, bottom sediment, and biota associated with irrigation drainage in the Dolores Project and the Macos River basin, southwestern Colorado, 1994

    Science.gov (United States)

    Butler, D.L.; Osmundson, B.C.; Krueger, R.P.

    1997-01-01

    A reconnaissance investigation for the National Irrigation Water Quality Program in 1990 indicated elevated selenium concentrations in some water and biota samples collected in the Dolores Project in southwestern Colorado. High selenium concentrations also were indicated in bird samples collected in the Mancos Project in 1989. In 1994, field screenings were done in parts of the Dolores Project and Mancos River Basin to collect additional selenium data associated with irrigation inthose areas. Selenium is mobilized from soils in newly irrigated areas of the Dolores Project called the Dove Creek area, which includes newly (since 1987) irrigated land north of Cortez and south of Dove Creek.Selenium was detected in 18 of 20stream samples, and the maximum concentration was 12micrograms per liter. The Dove Creek area is unique compared to other study areas of the National Irrigation Water Quality Program becauseselenium concentrations probably are indicative of initial leaching conditions in a newly irrigated area.Selenium concentrations in nine shallow soil samples from the Dove Creek area ranged from 0.13 to 0.20 micrograms per gram. Selenium concentrations in bottom sediment from six ponds were less than the level of concern for fish and wildlife of 4 micrograms per gram. Many biota samples collected in the Dove Creek area had elevated selenium concentrations when compared to various guidelines and effect levels,although selenium concentrations in water, soil, and bottom sediment were relatively low. Selenium concentrations in 12 of 14 aquatic-invertebratesamples from ponds exceeded 3 micrograms per gram dry weight, a dietary guideline for protection of fish and wildlife. The mean seleniumconcentration of 10.3 micrograms per gram dry weight in aquatic bird eggs exceeded the guideline for reduced hatchability of 8 micrograms per gramdry weight. Two ponds in the Dove Creek area had a high selenium hazard rating based on a new protocol for assessing selenium hazard in

  16. Natural-color and color-infrared image mosaics of the Colorado River corridor in Arizona derived from the May 2009 airborne image collection

    Science.gov (United States)

    Davis, Philip A.

    2013-01-01

    The Grand Canyon Monitoring and Research Center (GCMRC) of the U.S. Geological Survey (USGS) periodically collects airborne image data for the Colorado River corridor within Arizona (fig. 1) to allow scientists to study the impacts of Glen Canyon Dam water release on the corridor’s natural and cultural resources. These data are collected from just above Glen Canyon Dam (in Lake Powell) down to the entrance of Lake Mead, for a total distance of 450 kilometers (km) and within a 500-meter (m) swath centered on the river’s mainstem and its seven main tributaries (fig. 1). The most recent airborne data collection in 2009 acquired image data in four wavelength bands (blue, green, red, and near infrared) at a spatial resolution of 20 centimeters (cm). The image collection used the latest model of the Leica ADS40 airborne digital sensor (the SH52), which uses a single optic for all four bands and collects and stores band radiance in 12-bits. Davis (2012) reported on the performance of the SH52 sensor and on the processing steps required to produce the nearly flawless four-band image mosaic (sectioned into map tiles) for the river corridor. The final image mosaic has a total of only 3 km of surface defects in addition to some areas of cloud shadow because of persistent inclement weather during data collection. The 2009 four-band image mosaic is perhaps the best image dataset that exists for the entire Arizona part of the Colorado River. Some analyses of these image mosaics do not require the full 12-bit dynamic range or all four bands of the calibrated image database, in which atmospheric scattering (or haze) had not been removed from the four bands. To provide scientists and the general public with image products that are more useful for visual interpretation, the 12-bit image data were converted to 8-bit natural-color and color-infrared images, which also removed atmospheric scattering within each wavelength-band image. The conversion required an evaluation of the

  17. Enhanced and updated spatially referenced statistical assessment of dissolved-solids load sources and transport in streams of the Upper Colorado River Basin

    Science.gov (United States)

    Miller, Matthew P.; Buto, Susan G.; Lambert, Patrick M.; Rumsey, Christine A.

    2017-03-07

    Approximately 6.4 million tons of dissolved solids are discharged from the Upper Colorado River Basin (UCRB) to the Lower Colorado River Basin each year. This results in substantial economic damages, and tens of millions of dollars are spent annually on salinity control projects designed to reduce salinity loads in surface waters of the UCRB. Dissolved solids in surface water and groundwater have been studied extensively over the past century, and these studies have contributed to a conceptual understanding of sources and transport of dissolved solids. This conceptual understanding was incorporated into a Spatially Referenced Regressions on Watershed Attributes (SPARROW) model to examine sources and transport of dissolved solids in the UCRB. The results of this model were published in 2009. The present report documents the methods and data used to develop an updated dissolved-solids SPARROW model for the UCRB, and incorporates data defining current basin attributes not available in the previous model, including delineation of irrigated lands by irrigation type (sprinkler or flood irrigation), and calibration data from additional monitoring sites.Dissolved-solids loads estimated for 312 monitoring sites were used to calibrate the SPARROW model, which predicted loads for each of 10,789 stream reaches in the UCRB. The calibrated model provided a good fit to the calibration data as evidenced by R2 and yield R2 values of 0.96 and 0.73, respectively, and a root-mean-square error of 0.47. The model included seven geologic sources that have estimated dissolved-solids yields ranging from approximately 1 to 45 tons per square mile (tons/mi2). Yields generated from irrigated agricultural lands are substantially greater than those from geologic sources, with sprinkler irrigated lands generating an average of approximately 150 tons/mi2 and flood irrigated lands generating between 770 and 2,300 tons/mi2 depending on underlying lithology. The coefficients estimated for six

  18. Basal Resources in Backwaters of the Colorado River Below Glen Canyon Dam-Effects of Discharge Regimes and Comparison with Mainstem Depositional Environments

    Science.gov (United States)

    Behn, Katherine E.; Kennedy, Theodore A.; Hall, Robert O.

    2010-01-01

    Eight species of fish were native to the Colorado River before the closure of Glen Canyon Dam, but only four of these native species are currently present. A variety of factors are responsible for the loss of native fish species and the limited distribution and abundance of those that remain. These factors include cold and constant water temperatures, predation and competition with nonnative fish species, and food limitation. Backwaters are areas of stagnant flow in a return-current channel and are thought to be critical rearing habitat for juvenile native fish. Backwaters can be warmer than the main channel and may support higher rates of food production. Glen Canyon Dam is a peaking hydropower facility and, as a result, has subdaily variation in discharge because of changes in demand for power. Stable daily discharges may improve the quality of nearshore rearing habitats such as backwaters by increasing warming, stabilizing the substrate, and increasing food production. To evaluate whether backwaters have greater available food resources than main-channel habitats, and how resource availability in backwaters is affected by stable flow regimes, we quantified water-column and benthic food resources in backwaters seasonally for 1 year using both standing (organic matter concentration/density; chlorophyll a concentration/density; zooplankton concentration; benthic invertebrate density and biomass) and process measurements (chamber estimates of ecosystem metabolism). We compared backwater resource measurements with comparable data from main-channel habitats, and compared backwater data collected during stable discharge with data collected when there was subdaily variation in discharge. Rates of primary production in backwaters (mean gross primary production of 1.7 g O2/m2/d) and the main channel (mean gross primary production of 2.0 g O2/m2/d) were similar. Benthic organic matter standing stock (presented as ash-free dry mass-AFDM) was seven times higher in backwaters

  19. Radionuclide Data and Calculations and Loss-On-Ignition, X-Ray Fluorescence, and ICP-AES Data from Cores in Catchments of the Animas River, Colorado

    Science.gov (United States)

    Church, Stanley E.; Rice, Cyndi A.; Marot, Marci E.

    2008-01-01

    The U.S. Departments of Agriculture and Interior Abandoned Mine Lands (AML) Initiative is focused on the evaluation of the effect of past mining practices on the water quality and the riparian and aquatic habitats of impacted stream reaches downstream from historical mining districts located primarily on Federal lands. This problem is manifest in the eleven western states (west of longitude 102 degrees) where the majority of hardrock mines that had past production are located on Federal lands. In areas of temperate climate and moderate to heavy precipitation, the effects of rapid chemical and physical weathering of sulfides exposed on mine-waste dumps and acidic drainage from mines have resulted in elevated metal concentrations in the stream water and stream-bed sediment. The result of these mineral weathering processes has an unquantified impact on the quality of the water and the aquatic and riparian habitats that may limit their recreational resource value. One of the confounding factors in these studies is the determination of the component of metals derived from hydrothermally altered but unmined portions of these drainage basins. Several watersheds have been studied to evaluate the effects of acid mine drainage and acid rock drainage on the near-surface environment. The Animas River watershed in southwestern Colorado contains a large number of past-producing metal mines that have affected the watershed. Beginning in October 1996, the U.S. Geological Survey (USGS) began a collaborative study of these effects under the USGS-AML Initiative. In this report, we present the radionuclide and geochemical analytical results of sediment coring during 1997-1999 from two cores from oxbow lakes 0.5 mi. upstream from the 32nd Street Bridge near Durango, Colo., and from three cores from beaver ponds within the Mineral Creek drainage basin near Silverton, Colo.

  20. Characterization of mean transit time at large springs in the Upper Colorado River Basin, USA: A tool for assessing groundwater discharge vulnerability

    Science.gov (United States)

    Solder, John; Stolp, Bernard J.; Heilweil, Victor M.; Susong, David D.

    2016-01-01

    Environmental tracers (noble gases, tritium, industrial gases, stable isotopes, and radio-carbon) and hydrogeology were interpreted to determine groundwater transit-time distribution and calculate mean transit time (MTT) with lumped parameter modeling at 19 large springs distributed throughout the Upper Colorado River Basin (UCRB), USA. The predictive value of the MTT to evaluate the pattern and timing of groundwater response to hydraulic stress (i.e., vulnerability) is examined by a statistical analysis of MTT, historical spring discharge records, and the Palmer Hydrological Drought Index. MTTs of the springs range from 10 to 15,000 years and 90 % of the cumulative discharge-weighted travel-time distribution falls within the range of 2−10,000 years. Historical variability in discharge was assessed as the ratio of 10–90 % flow-exceedance (R 10/90%) and ranged from 2.8 to 1.1 for select springs with available discharge data. The lag-time (i.e., delay in discharge response to drought conditions) was determined by cross-correlation analysis and ranged from 0.5 to 6 years for the same select springs. Springs with shorter MTTs (<80 years) statistically correlate with larger discharge variations and faster responses to drought, indicating MTT can be used for estimating the relative magnitude and timing of groundwater response. Results indicate that groundwater discharge to streams in the UCRB will likely respond on the order of years to climate variation and increasing groundwater withdrawals.

  1. Topographic and Acoustic Estimates of Grain-Scale Roughness from High-Resolution Multibeam Echo-Sounder: Examples from the Colorado River in Marble and Grand Canyons.

    Science.gov (United States)

    Buscombe, D.; Grams, P. E.

    2014-12-01

    High-frequency (several hundred kilohertz) multibeam echo-sounder (MBES) systems have the potential to provide complete coverage of large areas (km2) of the bed, rapidly (mins to hrs), at high resolution (cm2), and with high positional accuracy (cm). Here, we explore the use of MBES data to estimate grain-scale roughness of submerged riverbed sediment. There are two broad approaches: 1) using digital elevation models constructed from depth soundings, and 2) using acoustic backscatter. We discuss the relative merits of both approaches using examples from data collected on the Colorado River in Marble and Grand Canyons, Arizona, USA. The primary advantage of acoustic backscatter over topography from soundings, for the purposes of sediment classification, is the potential to distinguish between sediment at a higher resolution. This is because soundings are point measurements, whereas a recorded backscatter magnitude is the integral of backscattered sound from all scatterers in the insonified area. In addition, this acoustic return contains information about both the roughness and the hardness/impedance of the sediment. The statistics of backscatter magnitudes alone are found to be a poor discriminator between sediment types perhaps because, using our 400 kHz system, the scattering regime changes from Rayleigh (sound scattering by particles smaller than the sound wavelength) for fine sand, to geometric (scattering by larger-than-sound-wavelength particles) for substrates coarser than sand. However, simple measures derived from backscatter power spectra (namely, the variance, integral lengthscale, and the intercept and slope from a power-law form - see Figure) are found to distinguish between patches of sand, gravel, cobbles and boulders. Using this dependence, we present a new data-driven approach to classify grain-scale roughness, developed by comparing the spectral properties of backscatter with bed-sediment observations using geo-referenced underwater video.

  2. Real-time estimation of snow water equivalent in the Upper Colorado River Basin using MODIS-based SWE Reconstructions and SNOTEL data

    Science.gov (United States)

    Schneider, Dominik; Molotch, Noah P.

    2016-10-01

    Changes in climate necessitate improved snowpack information to better represent anomalous distributions of snow water equivalent (SWE) and improve water resource management. We estimate the spatial distribution of SWE for the Upper Colorado River basin weekly from January to June 2001-2012 in quasireal-time by two regression techniques: a baseline regression of in situ operationally measured point SWE using only physiographic information and regression of these in situ points combining both physiographic information and historical SWE patterns from a remote sensing-based SWE reconstruction model. We compare the baseline regression approach to our new regression in the context of spatial snow surveys and operational snow measuring stations. When compared to independent distributed snow surveys, the new regression reduces the bias of SWE estimates from -5.5% to 0.8%, and RMSE of the SWE estimates by 8% from 0.25 m to 0.23 m. Notable improvements were observed in alpine terrain with bias declining from -38% to only 3.4%, and RMSE was reduced by 13%, from 0.47 to 0.41 m. The mean increase in cross-validated r2 for the new regression compared to the baseline regression is from 0.22 to 0.33. The largest increase in r2 in any one year is 0.19, an 83% improvement. The new regression estimates, on average, 31% greater SWE depth than the baseline regression in areas above 3000 m elevation, which contributes up to 66% of annual SWE volume in the driest year. This indicates that the historical SWE patterns from the reconstruction adds information to the interpolation beyond the physiographic conditions represented by the SNOTEL network. Given that previous works using SWE reconstructions were limited to retrospective analyses by necessity, the work presented here represents an important contribution in that it extends SWE reconstructions to real-time applications and illustrates that doing so significantly improves the accuracy of SWE estimates.

  3. Vegetation dynamics in response to water inflow rates and fire in a brackish Typha domingensis Pers. marsh in the delta of the Colorado River, Mexico

    Science.gov (United States)

    Mexicano, Lourdes; Nagler, Pamela L.; Zamora-Arroyo, Francisco; Glenn, Edward P.

    2012-01-01

    The Cienega de Santa Clara is a 5600 ha, anthropogenic wetland in the delta of the Colorado River in Mexico. It is the inadvertent creation of the disposal of brackish agricultural waste water from the U.S. into the intertidal zone of the river delta in Mexico, but has become an internationally important wetland for resident and migratory water birds. We used high resolution Quickbird and WorldView-2 images to produce seasonal vegetation maps of the Cienega before, during and after a test run of the Yuma Desalting Plant, which will remove water from the inflow stream and replace it with brine. We also used moderate resolution, 16-day composite NDVI imagery from the Moderate Resolution Imaging Spectrometer (MODIS) sensors on the Terra satellite to determine the main factors controlling green vegetation density over the years 2000–2011. The marsh is dominated by Typha domingensis Pers. with Phragmites australis (Cav.) Trin. Ex Steud. as a sub-dominant species in shallower marsh areas. The most important factor controlling vegetation density was fire. Spring fires in 2006 and 2011 were followed by much more rapid green-up of T. domingensis in late spring and 30% higher peak summer NDVI values compared to non-fire years (P < 0.001). Fires removed thatch and returned nutrients to the water, resulting in more vigorous vegetation growth compared to non-fire years. The second significant (P < 0.01) factor controlling NDVI was flow rate of agricultural drain water from the U.S. into the marsh. Reduced summer flows in 2001 due to canal repairs, and in 2010 during the YDP test run, produced the two lowest NDVI values of the time series from 2000 to 2011 (P < 0.05). Salinity is a further determinant of vegetation dynamics as determined by greenhouse experiments, but was nearly constant over the period 2000–2011, so it was not a significant variable in regression analyses. It is concluded that any reduction in inflow volumes will result in a linear decrease in green foliage

  4. Single-Nucleotide Polymorphisms Reveal Spatial Diversity Among Clones of Yersinia pestis During Plague Outbreaks in Colorado and the Western United States.

    Science.gov (United States)

    Lowell, Jennifer L; Antolin, Michael F; Andersen, Gary L; Hu, Ping; Stokowski, Renee P; Gage, Kenneth L

    2015-05-01

    In western North America, plague epizootics caused by Yersinia pestis appear to sweep across landscapes, primarily infecting and killing rodents, especially ground squirrels and prairie dogs. During these epizootics, the risk of Y. pestis transmission to humans is highest. While empirical models that include climatic conditions and densities of rodent hosts and fleas can predict when epizootics are triggered, bacterial transmission patterns across landscapes, and the scale at which Y. pestis is maintained in nature during inter-epizootic periods, are poorly defined. Elucidating the spatial extent of Y. pestis clones during epizootics can determine whether bacteria are propagated across landscapes or arise independently from local inter-epizootic maintenance reservoirs. We used DNA microarray technology to identify single-nucleotide polymorphisms (SNPs) in 34 Y. pestis isolates collected in the western United States from 1980 to 2006, 21 of which were collected during plague epizootics in Colorado. Phylogenetic comparisons were used to elucidate the hypothesized spread of Y. pestis between the mountainous Front Range and the eastern plains of northern Colorado during epizootics. Isolates collected from across the western United States were included for regional comparisons. By identifying SNPs that mark individual clones, our results strongly suggest that Y. pestis is maintained locally and that widespread epizootic activity is caused by multiple clones arising independently at small geographic scales. This is in contrast to propagation of individual clones being transported widely across landscapes. Regionally, our data are consistent with the notion that Y. pestis diversifies at relatively local scales following long-range translocation events. We recommend that surveillance and prediction by public health and wildlife management professionals focus more on models of local or regional weather patterns and ecological factors that may increase risk of widespread

  5. Natural-color and color-infrared image mosaics of the Colorado River corridor in Arizona derived from the May 2009 airborne image collection

    Science.gov (United States)

    Davis, Philip A.

    2013-01-01

    The Grand Canyon Monitoring and Research Center (GCMRC) of the U.S. Geological Survey (USGS) periodically collects airborne image data for the Colorado River corridor within Arizona (fig. 1) to allow scientists to study the impacts of Glen Canyon Dam water release on the corridor’s natural and cultural resources. These data are collected from just above Glen Canyon Dam (in Lake Powell) down to the entrance of Lake Mead, for a total distance of 450 kilometers (km) and within a 500-meter (m) swath centered on the river’s mainstem and its seven main tributaries (fig. 1). The most recent airborne data collection in 2009 acquired image data in four wavelength bands (blue, green, red, and near infrared) at a spatial resolution of 20 centimeters (cm). The image collection used the latest model of the Leica ADS40 airborne digital sensor (the SH52), which uses a single optic for all four bands and collects and stores band radiance in 12-bits. Davis (2012) reported on the performance of the SH52 sensor and on the processing steps required to produce the nearly flawless four-band image mosaic (sectioned into map tiles) for the river corridor. The final image mosaic has a total of only 3 km of surface defects in addition to some areas of cloud shadow because of persistent inclement weather during data collection. The 2009 four-band image mosaic is perhaps the best image dataset that exists for the entire Arizona part of the Colorado River. Some analyses of these image mosaics do not require the full 12-bit dynamic range or all four bands of the calibrated image database, in which atmospheric scattering (or haze) had not been removed from the four bands. To provide scientists and the general public with image products that are more useful for visual interpretation, the 12-bit image data were converted to 8-bit natural-color and color-infrared images, which also removed atmospheric scattering within each wavelength-band image. The conversion required an evaluation of the

  6. Los usos del Río Colorado y la subsistencia de los indígenas Cucapá en el valle de Mexicali. 1852-1944

    Directory of Open Access Journals (Sweden)

    José Alfredo Gómez Estrada

    1995-01-01

    Full Text Available This article describes how, in tbe flrst three decades of tbe present century, the population of the United States and Mexico living in the Imperial Valley and the Mexicali Valley used the Colorado River to develop a modern, irrigation-based agriculture in the river' s delta zone. It established connections between events and processes related to tbe Cucapá Indians, the native inhabitants of this region.

  7. Modeled Combined Extent of All Columbia River Basalt Units (CRB_extent4xconnections)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This shapefile was created as a boundary for the Columbia River Basalt extent and a buffered version was used to clip the geomodel unit grids. As part of a U.S....

  8. Timber resource statistics for the Willow block, Susitna River Basin multiresource inventory unit, Alaska, 1978.

    Science.gov (United States)

    Theodore S. Setzer; Bert R. Mead; Gary L. Carroll

    1984-01-01

    A multiresource inventory of the Willow block, Susitna River basin inventory unit, was conducted in 1978. Statistics on forest area, timber volumes, and growth and mortality from this inventory are presented. Timberland area is estimated at 230,200 acres and net growing stock volume, mostly birch, at 231.9 million cubic feet. Net annual growth of growing stock is...

  9. Timber resource statistics for the Upper Susitna block, Susitna River basin multiresource inventory unit, Alaska, 1980.

    Science.gov (United States)

    Bert R. Mead; Theodore S. Setzer; Gary L. Carroll

    1985-01-01

    A multiresource inventory of the Upper Susitna block, Susitna River basin inventory unit, was conducted in 1980. Statistics on forest area, timber volumes, and annual growth from this inventory are presented. Timberland area is estimated at 112,130 acres, and net growing stock volume, mostly hardwood, is 84.6 million cubic feet. Net annual growth of growing stock is...

  10. Timber resource statistics for the Beluga block, Susitna River basin multiresource inventory unit, Alaska, 1980.

    Science.gov (United States)

    Gary L. Carroll; Theodore S. Setzer; Bert R. Mead

    1985-01-01

    A multiresource inventory of the Beluga block, Susitna River basin inventory unit, was conducted in 1980. Statistics on forest area, timber volumes, and growth and mortality from this inventory are presented. Timberland area is estimated at 131,740 acres and net growing stock volume, mostly hardwood, is 99.4 million cubic feet. Net annual growth of growing stock is...

  11. Timber resource statistics for the Talkeetna block, Susitna River basin multiresource inventory unit, Alaska, 1979.

    Science.gov (United States)

    Theodore S. Setzer; Gary L. Carroll; Bert R. Mead

    1984-01-01

    A multiresource inventory of the Talkeetna block, Susitna River basin inventory unit, was conducted in 1979. Statistics on forest area, timber volumes, and growth and mortality from this inventory are presented. Timberland area is estimated at 562,105 acres and net growing stock volume, mostly hardwood, at 574.7 million cubic feet. Net annual growth of growing stock is...

  12. Social-value maps for Arapaho, Roosevelt, Medicine Bow, Routt, and White River National Forests, Colorado and Wyoming

    Science.gov (United States)

    Ancona, Zachary H.; Semmens, Darius J.; Sherrouse, Benson C.

    2016-03-25

    Executive SummaryThe continued pressures of population growth on the life-sustaining, economic, and cultural ecosystem services provided by our national forests, particularly those located near rapidly growing urban areas, present ongoing challenges to forest managers. Achieving an effective assessment of these ecosystem services includes a proper accounting of the ecological, economic, and social values attributable to them. However, assessments of ecosystem goods and services notably lack information describing the spatial distribution and relative intensity of social values—the perceived, nonmarket values derived particularly from cultural ecosystem services. A geographic information system (GIS) tool developed to fill this need, Social Values for Ecosystem Services (SolVES; http://solves.cr.usgs.gov), now provides the capability to generate social-value maps at a range of spatial scales. This report presents some of the methods behind SolVES, procedures needed to apply the tool, the first formal map products resulting from its application at a regional scale, and a discussion of the management implications associated with this type of information.In this study, we use SolVES to identify the location and relative intensity of social values as derived from survey responses gathered from residents living in counties adjacent to Arapaho, Roosevelt, Medicine Bow, Routt, and White River National Forests. The results, presented as a series of social-value maps, represent the first publicly available spatial data on social-value intensity for the southern Rocky Mountain region. Our analysis identified high-value areas for social values including aesthetic, biodiversity, and life sustaining within wilderness areas. Other values, like recreation, show high-value areas both within wilderness and throughout the general forest areas, which can be attributed to people using the forests for a diverse set of recreational activities. The economic social-value type was lower

  13. Short-Term Effects of the 2008 High-Flow Experiment on Macroinvertebrates in Colorado River Below Glen Canyon Dam, Arizona

    Science.gov (United States)

    Rosi-Marshall, Emma J.; Kennedy, Theodore A.; Kincaid, Dustin W.; Cross, Wyatt F.; Kelly, Holly A.W.; Behn, Kathrine A.; White, Tyler; Hall, Robert O.; Baxter, Colden V.

    2010-01-01

    Glen Canyon Dam has dramatically altered the physical environment (especially discharge regime, water temperatures, and sediment inputs) of the Colorado River. High-flow experiments (HFE) that mimic one aspect of the natural hydrograph (floods) were implemented in 1996, 2004, and 2008. The primary goal of these experiments was to increase the size and total area of sandbar habitats that provide both camping sites for recreational users and create backwaters (areas of stagnant flow in the lee of return-current eddies) that may be important as rearing habitat for native fish. Experimental flows might also positively or negatively alter the rainbow trout (Oncorhynchus mykiss) sport fishery in the clear tailwater reach below Glen Canyon Dam, Ariz., and native fish populations in downstream reaches (for example, endangered humpback chub, Gila cypha) through changes in available food resources. We examined the short-term response of benthic macroinvertebrates to the March 2008 HFE at three sites [river mile 0 (RM 0, 15.7 miles downriver from the dam), RM 62, and RM 225] along the Colorado River downstream from Glen Canyon Dam by sampling immediately before and then 1, 7, 14, and 30 days after the HFE. We selected these sites because of their importance to management; RM 0 has a valuable trout fishery, and RM 62 is the location of the largest population of the endangered humpback chub in the Grand Canyon. In addition to the short-term collection of samples, as part of parallel investigations, we collected 3 years of monthly (quarterly for RM 62) benthic macroinvertebrate samples that included 15 months of post-HFE data for all three sites, but processing of the samples is only complete for one site (RM 0). At RM 0, the HFE caused an immediate 1.75 g AFDM/m2 (expressed as grams ash-free dry mass, or AFDM) reduction of macroinvertebrate biomass that was driven by significant reductions in the biomass of the two dominant taxa in this reach-Potamopyrgus antipodarum (New

  14. Identification and evaluation of scientific uncertainties related to fish and aquatic resources in the Colorado River, Grand Canyon - summary and interpretation of an expert-elicitation questionnaire

    Science.gov (United States)

    Kennedy, Theodore A.

    2013-01-01

    Identifying areas of scientific uncertainty is a critical step in the adaptive management process (Walters, 1986; Runge, Converse, and Lyons, 2011). To identify key areas of scientific uncertainty regarding biologic resources of importance to the Glen Canyon Dam Adaptive Management Program, the Grand Canyon Monitoring and Research Center (GCMRC) convened Knowledge Assessment Workshops in May and July 2005. One of the products of these workshops was a set of strategic science questions that highlighted key areas of scientific uncertainty. These questions were intended to frame and guide the research and monitoring activities conducted by the GCMRC in subsequent years. Questions were developed collaboratively by scientists and managers. The questions were not all of equal importance or merit—some questions were large scale and others were small scale. Nevertheless, these questions were adopted and have guided the research and monitoring efforts conducted by the GCMRC since 2005. A new round of Knowledge Assessment Workshops was convened by the GCMRC in June and October 2011 and January 2012 to determine whether the research and monitoring activities conducted since 2005 had successfully answered some of the strategic science questions. Oral presentations by scientists highlighting research findings were a centerpiece of all three of the 2011–12 workshops. Each presenter was also asked to provide an answer to the strategic science questions that were specific to the presenter’s research area. One limitation of this approach is that these answers represented the views of the handful of scientists who developed the presentations, and, as such, they did not incorporate other perspectives. Thus, the answers provided by presenters at the Knowledge Assessment Workshops may not have accurately captured the sentiments of the broader group of scientists involved in research and monitoring of the Colorado River in Glen and Grand Canyons. Yet a fundamental ingredient of

  15. Abundance Trends and Status of the Little Colorado River Population of Humpback Chub: An Update Considering Data From 1989-2008

    Science.gov (United States)

    Coggins,, Lewis G.; Walters, Carl J.

    2009-01-01

    Mark-recapture methods have been used for the past two decades to assess trends in adult abundance and recruitment of the Little Colorado River (LCR) population of humpback chub. These methods indicate that the adult population declined through the 1980s and early 1990s but has been increasing for the past decade. Recruitment appears also to have increased, particularly in the 2003-4 period. Considering a range of assumed natural mortality-rates and magnitude of ageing error, it is unlikely that there are currently less than 6,000 adults or more than 10,000 adults. Our best estimate of the current adult (age 4 years or more) population is approximately 7,650 fish. Recent humpback chub assessments using the Age-Structured Mark-Recapture model (ASMR) and reported in 2006 (Melis and others, 2006) and 2008 (Coggins, 2008a,b) have provided abundance and recruitment trend estimates that have changed progressively over time as more data are considered by the model. The general pattern of change implies a less severe decline in adult abundance during the late 1980s through early 1990s, with attendant changes in recruitment supporting this demographic pattern. We have been concerned that these changes are not indicative of the true population and may be associated with a 'retrospective' bias as additional data are included in the ASMR model. To investigate this possibility, we developed a realistic individual-based simulation model (IBM) to generate replicate artificial data sets with similar characteristics to the true humpback chub data. The artificial data have known abundance trends and we analyzed these data with ASMR. On the basis of these simulations, we believe that errors in assigning age (and therefore brood-year) to fish based on their length are likely to have caused the retrospective bias pattern seen in the assessments and to have caused both less severe trends in the adult abundance estimates and progressively more severe downward bias in estimates of adult

  16. Sizes of the Largest Possible Earthquakes in the Central and Eastern United States - Summary of a Workshop, September 8-9, 2008, Golden, Colorado

    Science.gov (United States)

    Wheeler, Russell L.

    2009-01-01

    Most probabilistic seismic-hazard assessments require an estimate of Mmax, the magnitude (M) of the largest earthquake that is thought possible within a specified area. In seismically active areas such as some plate boundaries, large earthquakes occur frequently enough that Mmax might have been observed directly during the historical period. In less active regions like most of the Central and Eastern United States and adjacent Canada, large earthquakes are much less frequent and generally Mmax must be estimated indirectly. The indirect-estimation methods are many, their results vary widely, and opinions differ as to which methods are valid. This lack of consensus about Mmax estimation increases the uncertainty of hazard assessments for planned nuclear power reactors and increases design and construction costs. Accordingly, the U.S. Geological Survey and the U.S. Nuclear Regulatory Commission held an open workshop on Mmax estimation in the Central and Eastern United States and adjacent Canada. The workshop was held on Monday and Tuesday, September 8 and 9, 2008, at the U.S. Geological Survey offices in Golden, Colorado. Thirty-five people attended. The workshop goals were to reach consensus on one or more of: (1) the relative merits of the various methods of Mmax estimation, (2) which methods are invalid, (3) which methods are promising but not yet ready for use, and (4) what research is needed to reach consensus on the values and relative importance of the individual estimation methods.

  17. Rivers as borders, uniting or dividing? The effect of topography and implications for catchment management.

    Science.gov (United States)

    Smedley, D A; Rowntree, K M

    2012-01-01

    South Africa's water resources are unequally distributed over space and time and an already stressed water resource situation will only be exacerbated by climate change if current predictions are correct. The potential for conflict over increasingly strained water resources in South Africa is thus very real. In order to deal with these complex problems, national legislation is demanding that water resource management be decentralized to the local level where active participation can take place in an integrated manner in accordance with the principles of Integrated Water Resource Management (IWRM). However, administrative and political boundaries rarely match those of catchments as, throughout South Africa, rivers have been employed extensively to delineate administrative and political boundaries at a number of spatial scales. The aim of this research is to determine if rivers act as dividing or uniting features in a socio-political landscape and whether topography will influence their role in this context. The Orange-Senqu River is used as a case study. This paper goes on to consider the implications of this for catchment management in South Africa. No study known to the authors has explored the effect of the river itself, and its topographic setting, on the drivers that foster either conflict or cooperation, and allow for participatory management. This study presents evidence that the topography of a catchment has the ability to aggravate or reduce the impact of the variables considered by water managers and thereby influence the role of a river as a dividing or uniting feature. South Africa's proposed form of decentralized water management will have to contend with the effects of different topographies on the way in which rivers are perceived and utilized.

  18. Looking beyond the shores of the United Kingdom: addenda for the application of River Habitat Survey in Southern European rivers

    Directory of Open Access Journals (Sweden)

    Joanna L. KEMP

    2002-08-01

    Full Text Available River Habitat Survey (RHS is a system which records and quantifies the physical and vegetational structure of river channels and their immediate floodplains. In the United Kingdom, where it has been applied since the 1990s, it has brought an understanding of state of rivers nationally and has proved to be a useful part of scientific investigation. It is now obvious that such a method should be applied more widely, especially in the European context, where river data is lacking for many countries and there is a need for a standard, internationally comparable method. In this paper an extension to the basic survey method is presented, with the aim of improving the detail and quality of data collected for highly dynamic, braided rivers, more common in the rest of Europe, particularly the south, than in the UK itself. The changes to the survey form included the recording of secondary flow and substrate types for each transect, in addition to the usual recording of primary types. Where more than one wetted channel was present data were collected for both the main and secondary channels. These were common in the areas studied, for instance in autumn 2000 secondary channels were found at 9 out of 11 sites in northern Italy and 4 out of 11 sites in the south. Additionally, the results showed that with the recording of both primary and secondary flow types for each transect the average number of flow types found per site was increased by between 1 - 2.2. For substrate types the average increase per site was close to 1. Certain flow types, in particular ‘chute’ and ‘no perceptible’, and substrate types, for example ‘sand’, tended to be under-represented by the basic survey method. The relevance and implications of these results are discussed with respect to the southern European situation and the point is made that the detail required from RHS depends on the original motivation for choosing to apply it. Where it is part of a detailed biological

  19. Change in the Magnitude of River Flooding in the United States, 1965-2015

    Science.gov (United States)

    This figure shows changes in the size and frequency of flooding events in rivers and streams in the United States between 1965 and 2015. Blue upward-pointing symbols show locations where floods have become larger; brown downward-pointing symbols show locations where floods have become smaller. Data were analyzed by Louise Slater and Gabriele Villarini at the University of Iowa. For more information: www.epa.gov/climatechange/science/indicators

  20. Persistent organic pollutants in fish tissue in the mid-continental great rivers of the United States

    Science.gov (United States)

    Blacksom, Karen A.; Walters, David M.; Jicha, Terri M.; Lazorchak, James M.; Angradi, Theodore R.; Bolgrien, David W.

    2010-01-01

    Great rivers of the central United States (Upper Mississippi, Missouri, and Ohio rivers) are valuable economic and cultural resources, yet until recently their ecological condition has not been well quantified. In 2004–2005, as part of the Environmental Monitoring and Assessment Program for Great River Ecosystems (EMAP-GRE), we measured legacy organochlorines (OCs) (pesticides and polychlorinated biphenyls, PCBs) and emerging compounds (polybrominated diphenyl ethers, PBDEs) in whole fish to estimate human and wildlife exposure risks from fish consumption. PCBs, PBDEs, chlordane, dieldrin and dichlo