WorldWideScience

Sample records for francisco bay california

  1. San Francisco Bay, California 1 arc-second DEM

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 1-second San Francisco Bay, California Elevation Grid provides bathymetric data in ASCII raster format of 1-second resolution in geographic coordinates. This...

  2. Factors affecting reproductive success of the California clapper rail (Rallus longirostris obsoletus) in San Francisco Bay

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — We assessed the reproductive success of the California clapper rail (Rallus longirostris obsoletus), an endangered species restricted to San Francisco Bay, and the...

  3. Bottom boundary layer in south San Francisco Bay, California

    Science.gov (United States)

    Cheng, Ralph T.; Gartner, Jeffrey W.; Smith, Richard E.

    1997-01-01

    Detailed velocity distributions within the benthic turbulent boundary layer were measured by a Broad Band Acoustic Doppler Current Profiler (BB-ADCP) in South San Francisco Bay, California. In "mode 5", the BB-ADCP was able to measure velocity in 5 cm increments. The validation of these measurements was achieved by comparing the BB-ADCP measurements with the velocities measured by a Narrow Band Acoustic Doppler Current Profiler (NB-ADCP) in close proximity. There were thirty-three (33) velocity time-series measured by the BB-ADCP beginning at 7 cm above bed and extending to 175 cm in water column for about two weeks. The velocities from locations at 7 cm and 12 cm above the bed were determined to be of lower accuracy, and they were not used in estimates of friction velocity, u.. The values of u. at 95% confidence level were determined with relative error less than 20%. The time-series of u. varied with velocity outside of the boundary layer, and responded to spring-neap tidal variations. Attempts to use acoustic backscatterance echo intensity to measure suspended sediment concentration showed prom ise, and merit consideration in future studies.

  4. Spatial and temporal trends of contaminants in eggs of wading birds from San Francisco Bay, California

    Energy Technology Data Exchange (ETDEWEB)

    Hothem, R.L.; Marois, K.C.; Wainwright, S.E. [National Biological Service, Davis, CA (United States); Roster, D.L. [Fish and Wildlife Service, Newark, CA (United States). San Francisco Bay National Wildlife Refuge; King, K.A. [Fish and Wildlife Service, Phoenix, AZ (United States). Ecological Services; Keldsen, T.J. [National Biological Service, Fort Collins, CO (United States). Midcontinent Ecological Science Center

    1995-08-01

    Between 1989 and 1991, reproduction by black-crowned night-herons (Nycticorax nycticorax) and snowy egrets (Egretta thula) was studied at sites in San Francisco Bay. Eggs were collected from these and other bay sites and from South Wilbur Flood Area, a reference site in California`s San Joaquin Valley. Eggs were analyzed for inorganic trace elements, organochlorine pesticides, and polychlorinated biphenyls (PCBs). Results were compared among sites and years and with results of previous studies. There was some evidence of impaired reproduction, but concentrations of contaminants were generally lower than threshold levels for such effects. Egg hatchability was generally good, with predation being the factor that most limited reproductive success. Mean PCB concentrations were generally higher in eggs from the south end of San Francisco Bay than from the north, but the only temporal change, an increase, was observed at Alcatraz Island. There were spatial differences for p,p{prime}-DDE in night-heron eggs in 1990, but the highest mean concentration of DDE was in night-heron eggs from South Wilbur in 1991. Temporal declines in maximum concentrations of DDE in eggs were observed in the bay, but means did not change significantly over time. At Bair Island in the southern end of the bay, mean concentrations of mercury decreased while selenium increased in night-heron eggs over time, but there were no clear bay-wide spatial or temporal trends for either element.

  5. Spatial and temporal trends of contaminants in eggs of wading birds from San Francisco Bay, California

    Science.gov (United States)

    Hothem, R.L.; Roster, D.L.; King, K.A.; Keldsen, T.J.; Marois, Katherine C.; Wainwright, S.E.

    1995-01-01

    Between 1989 and 1991, reproduction by black-crowned night-herons (Nycticorax nycticorax) and snowy egrets (Egretta thula) was studied at sites in San Francisco Bay. Eggs were collected from these and other bay sites and from South Wilbur Flood Area, a reference site in California's San Joaquin Valley. Eggs were analyzed for inorganic trace elements, organochlorine pesticides, and polychlorinated biphenyls (PCBs). Results were compared among sites and years and with results of previous studies. There was some evidence of impaired reproduction, but concentrations of contaminants were generally lower than threshold levels for such effects. Egg hatchability was generally good, with predation being the factor that most limited reproductive success. Mean PCB concentrations were generally higher in eggs from the south end of San Francisco Bay than from the north, but the only temporal change, an increase, was observed at Alcatraz Island. There were spatial differences for p,p'-DDE in night-heron eggs in 1990, but the highest mean concentration of DDE was in night-heron eggs from South Wilbur in 1991. Temporal declines in maximum concentrations of DDE in eggs were observed in the bay, but means did not change significantly over time, At Bair Island in the southern end of the bay, mean concentrations of mercury decreased while selenium increased in night-heron eggs over time, but there were no clear bay-wide spatial or temporal trends for either element.

  6. California Least Tern breeding survey south San Francisco Bay

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report documents the field work conducted by members -of the South Bay Institute for Avian Studies during 1981. The primary purpose of this study was to survey...

  7. SummerHill Homes, San Francisco Bay Area, Fremont, California

    Energy Technology Data Exchange (ETDEWEB)

    None

    2006-10-01

    Building America fact sheet on SummerHill Homes of Northern California. The Villa Savona Homes in Fremont, California were built using 15% fly ash in concrete, engineered lumber for floors, high efficiency windows with Low-emissivity (Low-E) glass, and fi

  8. Description of gravity cores from San Pablo Bay and Carquinez Strait, San Francisco Bay, California

    Science.gov (United States)

    Woodrow, Donald L.; John L. Chin,; Wong, Florence L.; Fregoso, Theresa; Jaffe, Bruce E.

    2017-06-27

    Seventy-two gravity cores were collected by the U.S. Geological Survey in 1990, 1991, and 2000 from San Pablo Bay and Carquinez Strait, California. The gravity cores collected within San Pablo Bay contain bioturbated laminated silts and sandy clays, whole and broken bivalve shells (mostly mussels), fossil tube structures, and fine-grained plant or wood fragments. Gravity cores from the channel wall of Carquinez Strait east of San Pablo Bay consist of sand and clay layers, whole and broken bivalve shells (less than in San Pablo Bay), trace fossil tubes, and minute fragments of plant material.

  9. The critical role of islands for waterbird breeding and foraging habitat in managed ponds of the South Bay Salt Pond Restoration Project, South San Francisco Bay, California

    Science.gov (United States)

    Ackerman, Joshua T.; Hartman, C. Alex; Herzog, Mark P.; Smith, Lacy M.; Moskal, Stacy M.; De La Cruz, Susan E. W.; Yee, Julie L.; Takekawa, John Y.

    2014-01-01

    The South Bay Salt Pond Restoration Project aims to restore 50–90 percent of former salt evaporation ponds into tidal marsh in South San Francisco Bay, California. However, large numbers of waterbirds use these ponds annually as nesting and foraging habitat. Islands within ponds are particularly important habitat for nesting, foraging, and roosting waterbirds. To maintain current waterbird populations, the South Bay Salt Pond Restoration Project plans to create new islands within former salt ponds in South San Francisco Bay. In a series of studies, we investigated pond and individual island attributes that are most beneficial to nesting, foraging, and roosting waterbirds.

  10. Maps of Quaternary Deposits and Liquefaction Susceptibility in the Central San Francisco Bay Region, California

    Science.gov (United States)

    Witter, Robert C.; Knudsen, Keith L.; Sowers, Janet M.; Wentworth, Carl M.; Koehler, Richard D.; Randolph, Carolyn E.; Brooks, Suzanna K.; Gans, Kathleen D.

    2006-01-01

    This report presents a map and database of Quaternary deposits and liquefaction susceptibility for the urban core of the San Francisco Bay region. It supercedes the equivalent area of U.S. Geological Survey Open-File Report 00-444 (Knudsen and others, 2000), which covers the larger 9-county San Francisco Bay region. The report consists of (1) a spatial database, (2) two small-scale colored maps (Quaternary deposits and liquefaction susceptibility), (3) a text describing the Quaternary map and liquefaction interpretation (part 3), and (4) a text introducing the report and describing the database (part 1). All parts of the report are digital; part 1 describes the database and digital files and how to obtain them by downloading across the internet. The nine counties surrounding San Francisco Bay straddle the San Andreas fault system, which exposes the region to serious earthquake hazard (Working Group on California Earthquake Probabilities, 1999). Much of the land adjacent to the Bay and the major rivers and streams is underlain by unconsolidated deposits that are particularly vulnerable to earthquake shaking and liquefaction of water-saturated granular sediment. This new map provides a consistent detailed treatment of the central part of the 9-county region in which much of the mapping of Open-File Report 00-444 was either at smaller (less detailed) scale or represented only preliminary revision of earlier work. Like Open-File Report 00-444, the current mapping uses geomorphic expression, pedogenic soils, inferred depositional environments, and geologic age to define and distinguish the map units. Further scrutiny of the factors controlling liquefaction susceptibility has led to some changes relative to Open-File Report 00-444: particularly the reclassification of San Francisco Bay mud (Qhbm) to have only MODERATE susceptibility and the rating of artificial fills according to the Quaternary map units inferred to underlie them (other than dams - adf). The two colored

  11. Final Environmental Statement : Acquisition of lands for the San Francisco Bay National Wildlife Refuge California

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Federal Government proposes to acquire approximately 23,000 acres of land in the South San Francisco Bay region, Alameda, San Mateo and Santa Clara Counties, to...

  12. Breeding Season Study of the California Clapper Rail in San Francisco Bay, 1982

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The goals of this study were to further investigate the suitability of brackish marshes in south San Francisco Bay to support breeding rails and to examine how the...

  13. A survey of molecular marker compounds in sediments of San Francisco Bay, California

    Science.gov (United States)

    Hostettler, Frances D.; Rapp, John B.; Geological Survey (U.S.) Pereira, Wilfred E.; Kvenvolden, Keith A.

    1994-01-01

    An areal survey of surficial sediments in San Francisco Bay has been conducted to evaluate the presence of extractable organic compounds. Molecular marker compounds studied include hydrocarbons (PAH's), chlorinated pesticides, and other organic compounds that provide information on sources of organic input into the Bay. Fairly uniform source profiles are seen throughout the Bay. Biomarker profiles contain mature constituents indicating anthropogenic influences and extensive sediment reworking. The dominant input signatures in San Francisco Bay sediment are those of anthropogenic PAH's from combustion and other sources, and long chain n-alkanes and n-aldehydes from terrigenous vascular plants. A comparison of the sums of the combustion PAH's and the terrigenous n-alkanes shows that an anthropogenic influence is dominant in the most urban parts of the Bay close to shore, and in mid-Bay channel areas, and a terrigenous signature is dominant nearshore in San Pablo Bay and at the southernmost station in South Bay.

  14. Climate Change and Conservation Planning in California: The San Francisco Bay Area Upland Habitat Goals Approach

    Science.gov (United States)

    Branciforte, R.; Weiss, S. B.; Schaefer, N.

    2008-12-01

    Climate change threatens California's vast and unique biodiversity. The Bay Area Upland Habitat Goals is a comprehensive regional biodiversity assessment of the 9 counties surrounding San Francisco Bay, and is designing conservation land networks that will serve to protect, manage, and restore that biodiversity. Conservation goals for vegetation, rare plants, mammals, birds, fish, amphibians, reptiles, and invertebrates are set, and those goals are met using the optimization algorithm MARXAN. Climate change issues are being considered in the assessment and network design in several ways. The high spatial variability at mesoclimatic and topoclimatic scales in California creates high local biodiversity, and provides some degree of local resiliency to macroclimatic change. Mesoclimatic variability from 800 m scale PRISM climatic norms is used to assess "mesoclimate spaces" in distinct mountain ranges, so that high mesoclimatic variability, especially local extremes that likely support range limits of species and potential climatic refugia, can be captured in the network. Quantitative measures of network resiliency to climate change include the spatial range of key temperature and precipitation variables within planning units. Topoclimatic variability provides a finer-grained spatial patterning. Downscaling to the topoclimatic scale (10-50 m scale) includes modeling solar radiation across DEMs for predicting maximum temperature differentials, and topographic position indices for modeling minimum temperature differentials. PRISM data are also used to differentiate grasslands into distinct warm and cool types. The overall conservation strategy includes local and regional connectivity so that range shifts can be accommodated.

  15. Heavy Metals Concentration Levels in Soils throughout the East San Francisco Bay Area, California

    Science.gov (United States)

    Hagan, K.; Ramirez, N.; Diaz, J.; Cuff, K.; Adarkwah, N.

    2008-12-01

    Previous studies have shown that soils near structures made of pressure treated wood created before 2003 often contain high levels of arsenic, which was widely used in the processing of such wood. One such study, conducted by student scientists affiliated with the SF ROCKS program at San Francisco State University, found high levels of arsenic in soils collected from several children's play areas in San Francisco (Negrete, et al., 2006). Due to the known health risks associated with high concentrations of arsenic, and given a general lack of data related to soils of the East San Francisco Bay Area, the current study was initiated to determine whether or not dangerously high levels of arsenic exist in soils near public schools and playgrounds located in Richmond and Oakland, California. Soil samples were collected from approximately 100 locations in and around such areas, and analyzed for arsenic and a variety of other heavy metals concentration levels using an ICP spectrometer. Preliminary results demonstrate arsenic levels that exceed the EPA's 0.4 ppm action limit in 27 of the 100 sites from which samples were collected. Also, strong correlations between arsenic and various metals in the soil were found, such as arsenic with chromium (0.7022) and nickel (0.6588). Additionally, dangerously high levels of arsenic and lead were found in soils collected along the shores of a small lake fed by Leona Creek on the campus of Mills College in the Oakland foothills, approximately 2 kilometers downstream from a former iron sulphide mine. This occurrence constitutes evidence that the owner of the mine has not complied with recent orders from a local regulatory agency to make sure that mine effluents are safe.

  16. Seismic velocity structure and seismotectonics of the eastern San Francisco Bay region, California

    Science.gov (United States)

    Hardebeck, J.L.; Michael, A.J.; Brocher, T.M.

    2007-01-01

    The Hayward Fault System is considered the most likely fault system in the San Francisco Bay Area, California, to produce a major earthquake in the next 30 years. To better understand this fault system, we use microseismicity to study its structure and kinematics. We present a new 3D seismic-velocity model for the eastern San Francisco Bay region, using microseismicity and controlled sources, which reveals a ???10% velocity contrast across the Hayward fault in the upper 10 km, with higher velocity in the Franciscan Complex to the west relative to the Great Valley Sequence to the east. This contrast is imaged more sharply in our localized model than in previous regional-scale models. Thick Cenozoic sedimentary basins, such as the Livermore basin, which may experience particularly strong shaking during an earthquake, are imaged in the model. The accurate earthquake locations and focal mechanisms obtained by using the 3D model allow us to study fault complexity and its implications for seismic hazard. The relocated hypocenters along the Hayward Fault in general are consistent with a near-vertical or steeply east-dipping fault zone. The southern Hayward fault merges smoothly with the Calaveras fault at depth, suggesting that large earthquakes may rupture across both faults. The use of the 3D velocity model reveals that most earthquakes along the Hayward fault have near-vertical strike-slip focal mechanisms, consistent with the large-scale orientation and sense of slip of the fault, with no evidence for zones of complex fracturing acting as barriers to earthquake rupture.

  17. Historical methyl mercury in San Francisco Bay

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — San Francisco Bay, California is considered a mercury-impaired watershed. Elevated concentrations of mercury are found in water and sediment as well as fish and...

  18. Dietary mercury exposure to endangered California Clapper Rails in San Francisco Bay

    Science.gov (United States)

    Casazza, Michael L.; Ricca, Mark A.; Overton, Cory T.; Takekawa, John Y.; Merritt, Angela M.; Ackerman, Joshua T.

    2015-01-01

    California Clapper Rails (Rallus longirostris obsoletus) are an endangered waterbird that forage in tidal-marsh habitats that pose risks from mercury exposure. We analyzed total mercury (Hg) in six macro-invertebrate and one fish species representing Clapper Rail diets from four tidal-marshes in San Francisco Bay, California. Mercury concentrations among individual taxa ranged from lowest at Colma Creek (mean range: 0.09–0.2 μg/g dw) to highest at Cogswell (0.2–0.7), Laumeister (0.2–0.9) and Arrowhead Marshes (0.3–1.9). These spatial patterns for Hg matched patterns reported previously in Clapper Rail blood from the same four marshes. Over 25% of eastern mudsnails (Ilyanassa obsolete) and staghorn sculpin (Leptocottus armatus) exceeded dietary Hg concentrations (ww) often associated with avian reproductive impairment. Our results indicate that Hg concentrations vary considerably among tidal-marshes and diet taxa, and Hg concentrations of prey may provide an appropriate proxy for relative exposure risk for Clapper Rails.

  19. Increasing Hydrogen Ion Activity of Water in Two Reservoirs Supplying the San Francisco Bay Area, California

    Science.gov (United States)

    McColl, J. G.

    1981-10-01

    The hydrogen ion activity (H+) of water in two Sierra Nevada reservoirs (Pardee and Hetch Hetchy) that supply the San Francisco Bay area has been increasing with time over the period 1954-1979. This conclusion is based on weekly measurements ofpH at the two reservoirs and is supported by measurements of alkalinity which decreased at Pardee over the period 1944-1979. Based on linear models, the rate of the increasing (H+) was the same at both reservoirs, and (H+) varied concomitantly from year to year, suggesting a common, general cause. Mean monthly variation in (H+) corresponded to mean monthly variation in atmospheric pollution from a nine-county area around San Francisco Bay. The most likely cause of the increasing (H+) of reservoir waters is NOx from automobile exhausts primarily from the San Francisco Bay area.

  20. Waterbird egg mercury concentrations in response to wetland restoration in south San Francisco Bay, California

    Science.gov (United States)

    Ackerman, Joshua T.; Herzog, Mark P.; Hartman, Christopher A.; Watts, Trevor C.; Barr, Jarred R.

    2014-01-01

    The conversion of 50–90 percent of 15,100 acres of former salt evaporation ponds to tidal marsh habitat in the south San Francisco Bay, California, is planned as part of the South Bay Salt Pond Restoration Project. This large-scale habitat restoration may change the bioavailability of methylmercury. The South Bay already is known to have high methylmercury concentrations, with methylmercury concentrations in several waterbirds species more than known toxicity thresholds where avian reproduction is impaired. In this 2013 study, we continued monitoring bird egg mercury concentrations in response to the restoration of the Pond A8/A7/A5 Complex to a potential tidal marsh in the future. The restoration of the Pond A8/A7/A5 Complex began in autumn 2010, and the Pond A8 Notch was opened 5 feet (one of eight gates) to muted tidal action on June 1, 2011, and then closed in the winter. In autumn 2010, internal levees between Ponds A8, A7, and A5 were breached and water depths were substantially increased by flooding the Pond A8/A7/A5 Complex in February 2011. In June 2012, 15 feet (three of eight gates) of the Pond A8 Notch was opened, and then closed in December 2012. In June 2013, 15 feet of the Pond A8 Notch again was opened, and the Pond A8/A7/A5 Complex was a relatively deep and large pond with muted tidal action in the summer. This report synthesizes waterbird data from the 2013 breeding season, and combines it with our prior study’s data from 2010 and 2011.

  1. Crustal structure of the coastal and marine San Francisco Bay region, California

    Science.gov (United States)

    Parsons, Tom

    2002-01-01

    As of the time of this writing, the San Francisco Bay region is home to about 6.8 million people, ranking fifth among population centers in the United States. Most of these people live on the coastal lands along San Francisco Bay, the Sacramento River delta, and the Pacific coast. The region straddles the tectonic boundary between the Pacific and North American Plates and is crossed by several strands of the San Andreas Fault system. These faults, which are stressed by about 4 cm of relative plate motion each year, pose an obvious seismic hazard.

  2. A review of circulation and mixing studies of San Francisco Bay, California

    Science.gov (United States)

    Smith, Lawrence H.

    1987-01-01

    A description of the major characteristics and remaining unknowns of circulation and mixing in San Francisco Bay has been constructed from a review of published studies. From a broad perspective San Francisco Bay is an ocean-river mixing zone with a seaward flow equal to the sum of the river inflows less evaporation. Understanding of circulation and mixing within the bay requires quantification of freshwater inflows and ocean-bay exchanges, characterization of source-water variations, and separation of the within-bay components of circulation and mixing processes. Description of net circulation and mixing over a few days to a few months illustrates best the interactions of major components. Quantification of tidal circulation and mixing is also necessary because net circulation and mixing contain a large tide-induced component, and because tidal variations are dominant in measurements of stage, currents, and salinity. The discharge of the Sacramento-San Joaquin Delta into Suisun Bay is approximately 90 percent of the freshwater inflow to San Francisco Bay. Annual delta discharge is characterized by a winter season of high runoff and a summer season of low runoff. For the period 1956 to 1985 the mean of monthly discharges exceeded 1,000 cubic meters per second (35,000 cubic feet per second) for the months of December through April, whereas for July through October, it was less than 400 cubic meters per second (14,000 cubic feet per second). The months of November, May, and June commonly were transition months between these seasons. Large year-to-year deviations from this annual pattern have occurred frequently. Much less is known about the ocean-bay exchange process. Net exchanges depend on net seaward flow in the bay, tidal amplitude, and longshore coastal currents, but exchanges have not yet been measured successfully. Source-water variations are ignored by limiting discussion of mixing to salinity. The bay is composed of a northern reach, which is strongly

  3. Analysis of sediment, water, and biological samples from the Bay Farm Borrow Area, San Francisco Bay, California

    Energy Technology Data Exchange (ETDEWEB)

    Thom, R.M.; Lefkovitz, L.F. (Battelle/Marine Sciences Lab., Sequim, WA (United States))

    1991-08-01

    The Bay Farm Borrow Area (BFBA) of San Francisco Bay, California, is under consideration as a dredged-material disposal site by the US Army Corps of Engineers (USACE). As part of the analysis of the site, information is required on the quality of benthic biota, sediment, and water in the BFBA. The objective of this report was to provide data on infauna communities, sediment, and water chemistry from samples collected from the BFBA. The samples were collected, and the data will be analyzed by Science Applications International (SAIC). A total of four samples for sediment chemistry, four samples for water chemistry, and 7 samples for infauna communities were analyzed by the Battelle/Marine Sciences Laboratory (MSL). Water analyses included tests for dissolved organic carbon, total suspended solids, four metals, butyltins, polychlorinated biphenyls (PCBs), chlorinated pesticides, polynuclear aromatic hydrocarbons (PAHs), four phenols, and total phenol. Sediment samples were analyzed for percent solids, total organic carbon, total oil and grease, total petroleum hydrocarbons, grain size, 10 metals, butyltins, PCBs, chlorinated pesticides, PAHs, four phenols, and total phenol. The data along with controls and spike recovery analyses, are presented in tables, and the results are discussed in the text. The quality assurance/quality control criteria were met for the analyses as were the detection limits specified by the sponsor.

  4. Mercury in birds of San Francisco Bay-Delta, California: trophic pathways, bioaccumulation, and ecotoxicological risk to avian reproduction

    Science.gov (United States)

    Ackerman, Joshua T.; Eagles-Smith, Collin A.; Heinz, Gary; De La Cruz, Susan E. W.; Takekawa, John Y.; Miles, A. Keith; Adelsbach, Terrence L.; Herzog, Mark P.; Bluso-Demers, Jill D.; Demers, Scott A.; Herring, Garth; Hoffman, David J.; Hartman, Christopher A.; Willacker, James J.; Suchanek, Thomas H.; Schwarzbach, Steven E.; Maurer, Thomas C.

    2014-01-01

    San Francisco Bay Estuary in northern California has a legacy of mercury contamination, which could reduce the health and reproductive success of waterbirds in the estuary. The goal of this study was to use an integrated field and laboratory approach to evaluate the risks of mercury exposure to birds in the estuary. We examined mercury bioaccumulation, and other contaminants of concern, in five waterbird species that depend heavily on San Francisco Bay Estuary for foraging and breeding habitat: American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), Forster’s terns (Sterna forsteri), Caspian terns (Hydroprogne caspia), and surf scoters (Melanitta perspicillata). These species have different foraging habitats and diets that represent three distinct foraging guilds within the estuary’s food web. In this report, we provide an integrated synthesis of the primary findings from this study and results are synthesized from 54 peer-reviewed publications generated to date with other unpublished results.

  5. Under the Golden Gate bridge: views of the sea floor near the entrance to San Francisco Bay, California

    Science.gov (United States)

    Dartnell, Peter; Barnard, Patrick L.; Chin, John L.; Hanes, Daniel; Kvitek, Rikk G.; Iampietro, Pat J.; Gardner, James V.

    2006-01-01

    San Francisco Bay in Northern California is one of the largest and most altered estuaries within the United States. The sea floor within the bay as well as at its entrance is constantly changing due to strong tidal currents, aggregate mining, dredge disposal, and the creation of new land using artificial fill. Understanding this dynamic sea floor is critical for addressing local environmental issues, which include defining pollution transport pathways, deciphering tectonics, and identifying benthic habitats. Mapping commercial interests such as safe ship navigation and dredge disposal is also significantly aided by such understanding. Over the past decade, the U.S. Geological Survey (USGS), the National Oceanic and Atmospheric Administration (NOAA), and California State University, Monterey Bay (CSUMB) in cooperation with the U.S. Army Corps of Engineers (USACOE) and the Center for Integrative Coastal Observation, Research and Education (CICORE) have partnered to map central San Francisco Bay and its entrance under the Golden Gate Bridge using multibeam echosounders. These sonar systems can continuously map to produce 100 percent coverage of the sea floor at meter-scale resolution and thus produce an unprecedented view of the floor of the bay. This poster shows views of the sea floor in west-central San Francisco Bay around Alcatraz and Angel Islands, underneath the Golden Gate Bridge, and through its entrance from the Pacific Ocean. The sea floor is portrayed as a shaded relief surface generated from the multibeam data color-coded for depth from light blues for the shallowest values to purples for the deepest. The land regions are portrayed by USGS digital orthophotographs (DOQs) overlaid on USGS digital elevation models (DEMs). The water depths have a 4x vertical exaggeration while the land areas have a 2x vertical exaggeration.

  6. Subsurface structure of the East Bay Plain ground-water basin: San Francisco Bay to the Hayward fault, Alameda County, California

    Science.gov (United States)

    Catchings, R.D.; Borchers, J.W.; Goldman, M.R.; Gandhok, G.; Ponce, D.A.; Steedman, C.E.

    2006-01-01

    The area of California between the San Francisco Bay, San Pablo Bay, Santa Clara Valley, and the Diablo Ranges (East Bay Hills), commonly referred to as the 'East Bay', contains the East Bay Plain and Niles Cone ground-water basins. The area has a population of 1.46 million (2003 US Census), largely distributed among several cities, including Alameda, Berkeley, Fremont, Hayward, Newark, Oakland, San Leandro, San Lorenzo, and Union City. Major known tectonic structures in the East Bay area include the Hayward Fault and the Diablo Range to the east and a relatively deep sedimentary basin known as the San Leandro Basin beneath the eastern part of the bay. Known active faults, such as the Hayward, Calaveras, and San Andreas pose significant earthquake hazards to the region, and these and related faults also affect ground-water flow in the San Francisco Bay area. Because most of the valley comprising the San Francisco Bay area is covered by Holocene alluvium or water at the surface, our knowledge of the existence and locations of such faults, their potential hazards, and their effects on ground-water flow within the alluvial basins is incomplete. To better understand the subsurface stratigraphy and structures and their effects on ground-water and earthquake hazards, the U.S. Geological Survey (USGS), in cooperation with the East Bay Municipal Utility District (EBMUD), acquired a series of high-resolution seismic reflection and refraction profiles across the East Bay Plain near San Leandro in June 2002. In this report, we present results of the seismic imaging investigations, with emphasis on ground water.

  7. Gravity cores from San Pablo Bay and Carquinez Strait, San Francisco Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data release contains information on gravity cores that were collected by the U.S. Geological Survey in the area of San Pablo Bay and Carquinez Strait,...

  8. Sea level fluctuations in central California at subtidal to decadal and longer time scales with implications for San Francisco Bay, California

    Science.gov (United States)

    Ryan, H.F.; Noble, M.A.

    2007-01-01

    Sea level elevations from near the mouth of San Francisco Bay are used to describe the low-frequency variability of forcing of the coastal ocean on the Bay at a variety of temporal scales. About 90% of subtidal fluctuations in sea level in San Francisco Bay are driven by the sea level variations in the coastal ocean that propagate into the Bay at the estuary mouth. We use the 100-year sea level record available at San Francisco to document a 1.9 mm/yr mean sea level rise, and to determine fluctuations related to El Nino-Southern Oscillation (ENSO) and other climatic events. At time scales greater than 1 year, ENSO dominates the sea level signal and can result in fluctuations in sea level of 10-15 cm. Alongshore wind stress data from central California are also analyzed to determine the impact of changes in coastal elevation at the mouth of San Francisco Bay within the synoptic wind band of 2-30 days. At least 40% of the subtidal fluctuations in sea level of the Bay are tied to the large-scale regional wind field affecting sea level variations in the coastal ocean, with little local, direct wind forcing of the Bay itself. The majority of the subtidal sea level fluctuations within the Bay that are not related to the coastal ocean sea level signal are forced by an east-west sea level gradient resulting from tidally induced variations in sea level at specific beat frequencies that are enhanced in the northern reach of the Bay. River discharge into the Bay through the Sacramento and San Joaquin River Delta also contributes to the east-west gradient, but to a lesser degree. ?? 2007 Elsevier Ltd. All rights reserved.

  9. Phosphate oxygen isotope ratios as a tracer for sources and cycling of phosphate in North San Francisco Bay, California

    Science.gov (United States)

    McLaughlin, Karen; Kendall, Carol; Silva, Steven R.; Young, Megan; Paytan, Adina

    2006-09-01

    A seasonal analysis assesing variations in the oxygen isotopic composition of dissolved inorganic phosphate (DIP) was conducted in the San Francisco Bay estuarine system, California. Isotopic fractionation of oxygen in DIP (exchange of oxygen between phosphate and environmental water) at surface water temperatures occurs only as a result of enzyme-mediated, biological reactions. Accordingly, if phospate demand is low relative to input and phosphate is not heavily cycled in the ecosystem, the oxygen isotopic composition of DIP (δ18Op) will reflect the isotopic composition of the source of phosphate to the system. Such is the case for the North San Francisco Bay, an anthropogenically impacted estuary with high surface water phosphate concentrations. Variability in the δ18Op in the bay is primarily controlled by mixing of water masses with different δ18Op signatures. The δ18Op values range from 11.4‰ at the Sacramento River to 20.1‰ at the Golden Gate. Deviations from the two-component mixing model for the North Bay reflect additional, local sources of phosphate to the estuary that vary seasonally. Most notably, deviations from the mixing model occur at the confluence of a major river into the bay during periods of high river discharge and near wastewater treatment outlets. These data suggest that δ18Op can be an effective tool for identifying P point sources and understanding phosphate dynamics in estuarine systems.

  10. Phosphate oxygen isotope ratios as a tracer for sources and cycling of phosphate in North San Francisco Bay, California

    Science.gov (United States)

    McLaughlin, K.; Kendall, C.; Silva, S.R.; Young, M.; Paytan, A.

    2006-01-01

    A seasonal analysis assesing variations in the oxygen isotopic composition of dissolved inorganic phosphate (DIP) was conducted in the San Francisco Bay estuarine system, California. Isotopic fractionation of oxygen in DIP (exchange of oxygen between phosphate and environmental water) at surface water temperatures occurs only as a result of enzyme-mediated, biological reactions. Accordingly, if phospate demand is low relative to input and phosphate is not heavily cycled in the ecosystem, the oxygen isotopic composition of DIP (?? 18Op) will reflect the isotopic composition of the source of phosphate to the system. Such is the case for the North San Francisco Bay, an anthropogenically impacted estuary with high surface water phosphate concentrations. Variability in the ?? 18Op in the bay is primarily controlled by mixing of water masses with different ??18Op signatures. The ??18Op values range from 11.4??? at the Sacramento River to 20.1??? at the Golden Gate. Deviations from the two-component mixing model for the North Bay reflect additional, local sources of phosphate to the estuary that vary seasonally. Most notably, deviations from the mixing model occur at the confluence of a major river into the bay during periods of high river discharge and near wastewater treatment outlets. These data suggest that ??18Op can be an effective tool for identifying P point sources and understanding phosphate dynamics in estuarine systems. Copyright 2006 by the American Geophysical Union.

  11. Marsh expansion at Calaveras Point Marsh, South San Francisco Bay, California

    Science.gov (United States)

    Watson, Elizabeth Burke

    2008-07-01

    Studies of shoreline progradation along low-energy vegetated shorelines have been limited, as these environments are generally experiencing erosion rather than deposition, with extreme erosion rates frequently found. This study examined yearly changes along a vegetated shoreline at Calaveras Point Marsh, South San Francisco Bay, California, using aerial photography, to determine the roles of climatic, watershed, and coastal process in driving shoreline changes. In addition, sediment accumulation was monitored on a yearly basis at 48 locations across the marsh to determine the role of geomorphic factors in promoting accumulation. Calaveras Point Marsh was found to have expanded from 49.26 ± 5.2 to 165.7 ± 4.7 ha between 1975 and 2005. Although the rate of marsh expansion was not positively correlated with yearly variability in precipitation, local streamflow, delta outflow, water level observations, population growth, or ENSO indices, marsh growth was greater during years of higher than average temperatures. Warmer temperatures may have promoted the recruitment and growth of Spartina foliosa, a C 4 grass known to be highly responsive to temperature. Other factors, such as the formation of a coastal barrier, a recent change in the location of the mouth of the Guadalupe River, and channel readjustment in response to diking are credited with driving the bulk of the marsh expansion. Sediment accumulation was found to be high closest to channels and to the shoreline, at low elevations and in recently vegetated marsh. Globally, the pace of sea level rise exerts the primary control on wetland development and persistence. However, at local geographic scales, factors such as tectonic events, modifications to natural sediment transport pathways or land use changes may overwhelm the effects of regional sea level rise, and allow for wetlands to develop, expand and persist despite rapid sea level rise.

  12. Late Holocene δ 13C and pollen records of paleosalinity from tidal marshes in the San Francisco Bay estuary, California

    Science.gov (United States)

    Malamud-Roam, Frances; Lynn Ingram, B.

    2004-09-01

    Records of stable carbon isotopes (δ 13C) are presented from cores collected from four San Francisco Bay marshes and used as a proxy for changes in estuary salinity. The δ 13C value of organic marsh sediments are a reflection of the relative proportion of C 3 vs. C 4 plants occupying the surface, and can thus be used as a proxy for vegetation change on the marsh surface. The four marshes included in this study are located along a natural salinity gradient that exists in the San Francisco Bay, and records of vegetation change at all four sites can be used to infer changes in overall estuary paleosalinity. The δ 13C values complement pollen data from the same marsh sites producing a paleoclimate record for the late Holocene period in the San Francisco Bay estuary. The data indicate that there have been periods of higher-than-average salinity in the Bay estuary (reduced fresh water inflow), including 1600-1300 cal yr B.P., 1000-800 cal yr B.P., 300-200 cal yr B.P., and ca. A.D. 1950 to the present. Periods of lower-than-average salinity (increased fresh water inflow) occurred before 2000 cal yr B.P., from 1300 to 1200 cal yr B.P. and ca. 150 cal yr B.P. to A.D. 1950. A comparison of the timing of these events with records from the California coast, watershed, and beyond the larger drainage of the Bay reveals that the paleosalinity variations reflected regional precipitation.

  13. Late Holocene sedimentary environments of south San Francisco Bay, California, illustrated in gravity cores

    Science.gov (United States)

    Woodrow, Donald L.; Fregoso, Theresa A.; Wong, Florence L.; Jaffe, Bruce E.

    2014-01-01

    Data are reported here from 51 gravity cores collected from the southern part of San Francisco Bay by the U.S. Geological Survey in 1990. The sedimentary record in the cores demonstrates a stable geographic distribution of facies and spans a few thousand years. Carbon-14 dating of the sediments suggests that sedimentation rates average about 1 mm/yr. The geometry of the bay floor and the character of the sediment deposited have remained about the same in the time spanned by the cores. However, the sedimentary record over periods of centuries or decades is likely to be much more variable. Sediments containing a few bivalve shells and bivalve or oyster coquinas are most often found west of the main channel and near the San Mateo Bridge. Elsewhere in the south bay, shells are rare except in the southernmost reaches where scattered gastropod shells are found.

  14. Monitoring and modeling conditions for regional shallow landslide initiation in the San Francisco Bay area, California

    Science.gov (United States)

    Collins, B. D.; Stock, J. D.; Godt, J. W.

    2012-12-01

    Intense winter storms in the San Francisco Bay area (SFBA) of California often trigger widespread landsliding, including debris flows that originate as shallow (initiation thresholds are available for the SFBA, antecedent soil moisture conditions also play a major role in determining the likelihood for landslide generation from a given storm. Previous research has demonstrated that antecedent triggering conditions can be obtained using pre-storm precipitation thresholds (e.g., 250-400 mm of seasonal pre-storm rainfall). However, these types of thresholds do not account for the often cyclic pattern of wetting and drying that can occur early in the winter storm season (i.e. October - December), and which may skew the applicability of precipitation-only based thresholds. To account for these cyclic and constantly evolving soil moisture conditions, we have pursued methods to measure soil moisture directly and integrate these measurements into predictive analyses. During the past three years, the USGS installed a series of four subsurface hydrology monitoring stations in shallow landslide-prone locations of the SFBA to establish a soil-moisture-based antecedent threshold. In addition to soil moisture sensors, the monitoring stations are each equipped with piezometers to record positive pore water pressure that is likely required for shallow landslide initiation and a rain gauge to compare storm intensities with existing precipitation-based thresholds. Each monitoring station is located on a natural, grassy hillslope typically composed of silty sands, underlain by sandstone, sloping at approximately 30°, and with a depth to bedrock of approximately 1 meter - conditions typical of debris flow generation in the SFBA. Our observations reveal that various locations respond differently to seasonal precipitation, with some areas (e.g., Marin County) remaining at higher levels of saturation for longer periods of time during the winter compared to other areas (e.g., the East

  15. A new seamless, high-resolution digital elevation model of the San Francisco Bay-Delta Estuary, California

    Science.gov (United States)

    Fregoso, Theresa; Wang, Rueen-Fang; Ateljevich, Eli; Jaffe, Bruce E.

    2017-06-14

    Climate change, sea-level rise, and human development have contributed to the changing geomorphology of the San Francisco Bay - Delta (Bay-Delta) Estuary system. The need to predict scenarios of change led to the development of a new seamless, high-resolution digital elevation model (DEM) of the Bay – Delta that can be used by modelers attempting to understand potential future changes to the estuary system. This report details the three phases of the creation of this DEM. The first phase took a bathymetric-only DEM created in 2005 by the U.S. Geological Survey (USGS), refined it with additional data, and identified areas that would benefit from new surveys. The second phase began a USGS collaboration with the California Department of Water Resources (DWR) that updated a 2012 DWR seamless bathymetric/topographic DEM of the Bay-Delta with input from the USGS and modifications to fit the specific needs of USGS modelers. The third phase took the work from phase 2 and expanded the coverage area in the north to include the Yolo Bypass up to the Fremont Weir, the Sacramento River up to Knights Landing, and the American River up to the Nimbus Dam, and added back in the elevations for interior islands. The constant evolution of the Bay-Delta will require continuous updates to the DEM of the Delta, and there still are areas with older data that would benefit from modern surveys. As a result, DWR plans to continue updating the DEM.

  16. Comparison of noise characteristics of GPS position time-series between the San Francisco Bay area and Southern California networks

    Science.gov (United States)

    Langbein, J.; Svarc, J.; Murray-Moraleda, J.

    2008-12-01

    The continuous GPS networks located in both the San Francisco (SF) Bay region and Southern California have been installed to measure the deformation from long-wavelength, tectonic processes. The long time- series of position changes from the sites that make up these networks allow us to estimate the spectrum of background noise. Once the background noise has been characterized, it can be used as a benchmark to monitor changes in positions and to detect whether future position changes are consistent with the known, background-noise processes. Williams et al [2004] and Langbein [2008] have previously studied the noise characteristics of the Southern California Integrated GPS Network (SCIGN). In this paper, we use the methods of Langbein [2008] to characterize the noise from the Bay Area Regional Deformation (BARD) GPS network for comparison with results from SCIGN. In particular, we examine only the sites for which there exist more than 3.8 years of observations. Compared with more than 200 sites for SCIGN that existed at the time of Langbein's [2008] study, the BARD network, localized to the SF Bay area, has only 25 sites available for analysis. In addition, where the SCIGN network consists predominately of deeply braced monuments, the BARD network has a mix of monument types, including cement piers pinned to underlying rock, casing of borehole strainmeters, and rock pins. Only recently, with the installation of the Plate Boundary Observatory (PBO), have deeply braced monuments been installed in the SF Bay area. Preliminary examination of both the long-term and short-time noise suggests that there are no major differences in noise characteristics between sites in the SF Bay area and those of SCIGN. Furthermore, there are no large, systematic differences in noise between the differing monument types used in the SF Bay area; finer resolution of any differences is limited due to the lack of time-series with long records of observations.

  17. Comparison of sediment supply to San Francisco Bay from watersheds draining the Bay Area and the Central Valley of California

    Science.gov (United States)

    McKee, L.J.; Lewicki, M.; Schoellhamer, D.H.; Ganju, N.K.

    2013-01-01

    Quantifying suspended sediment loads is important for managing the world's estuaries in the context of navigation, pollutant transport, wetland restoration, and coastal erosion. To address these needs, a comprehensive analysis was completed on sediment supply to San Francisco Bay from fluvial sources. Suspended sediment, optical backscatter, velocity data near the head of the estuary, and discharge data obtained from the output of a water balance model were used to generate continuous suspended sediment concentration records and compute loads to the Bay from the large Central Valley watershed. Sediment loads from small tributary watersheds around the Bay were determined using 235 station-years of suspended sediment data from 38 watershed locations, regression analysis, and simple modeling. Over 16 years, net annual suspended sediment load to the head of the estuary from its 154,000 km2 Central Valley watershed varied from 0.13 to 2.58 (mean = 0.89) million metric t of suspended sediment, or an average yield of 11 metric t/km2/yr. Small tributaries, totaling 8145 km2, in the nine-county Bay Area discharged between 0.081 and 4.27 (mean = 1.39) million metric t with a mean yield of 212 metric t/km2/yr. The results indicate that the hundreds of urbanized and tectonically active tributaries adjacent to the Bay, which together account for just 5% of the total watershed area draining to the Bay and provide just 7% of the annual average fluvial flow, supply 61% of the suspended sediment. The small tributary loads are more variable (53-fold between years compared to 21-fold for the inland Central Valley rivers) and dominated fluvial sediment supply to the Bay during 10 out of 16 yr. If San Francisco Bay is typical of other estuaries in active tectonic or climatically variable coastal regimes, managers responsible for water quality, dredging and reusing sediment accumulating in shipping channels, or restoring wetlands in the world's estuaries may need to more carefully

  18. Review of wastewater problems and wastewater-management planning in the San Francisco Bay region, California

    Science.gov (United States)

    Hines, Walter G.

    1973-01-01

    The San Francisco Bay region has suffered adverse environmental effects related to the discharge of municipal-, industrial-, and agricultural- wastewater and storm-water runoff. Specific pollutional properties of theses discharges are not well understood in all cases although the toxic materials and aquatic-plant nutrients (biostimulants) found in municipal and industrial waterwater are considered to be a major cause of regional water-quality problems. Other water-quality problems in the region are commonly attributed to pesticides found in agricultural wastewater and potentially pathogenic bacteria in municipal-wastewater discharges and in storm-water runoff. The geographical distribution and magnitude of wastewater discharges in the bay region, particularly those from municipalities and industries, is largely a function of population, economic growth, and urban development. As might be expected, the total volume of wastewater has increased in a trend paralleling this growth and development. More significant, perhaps, is the fact that the total volume parameters such as BOD (biochemical oxygen demand), biostimulant concentrations, and toxicity, has increased despite large expenditures on new and improved municipal- and industrial-wastewater-treatment plants. Also, pollutant loadings from other major source, such as agriculture and storm-water runoff, have increased. At the time of writing (1972), many Federal, State, regional, and local agencies are engaged in a comprehensive wastewater-management-planning effort for the entire bay region. Initial objectives of this planning effort are: (1) the consolidation and coordination of loosely integrated wastewater-management facilities and (2) the elimination of wastewater discharges to ecologically sensitive areas, such as fresh-water streams and shallow extremities of San Francisco Bay. There has been some investigation of potential long-range wastewater-management alternatives based upon disposal in deep water in the

  19. Estuarine sedimentation, sediment character, and foraminiferal distribution in central San Francisco Bay, California

    Science.gov (United States)

    Chin, John L.; Woodrow, Donald L.; McGann, Mary; Wong, Florence L.; Fregoso, Theresa; Jaffe, Bruce E.

    2010-01-01

    Central San Francisco Bay is the deepest subembayment in the San Francisco Bay estuary and hence has the largest water volume of any of the subembayments. It also has the strongest tidal currents and the coarsest sediment within the estuary. Tidal currents are strongest over the west-central part of central bay and, correspondingly, this area is dominated by sand-size sediment. Much of the area east of a line from Angel Island to Alcatraz Island is characterized by muddy sand to sandy mud, and the area to the west of this line is sandy. The sand-size sediment over west-central bay furthermore is molded by the energetic tidal currents into bedforms of varying sizes and wavelengths. Bedforms typically occur in water depths of 15-25 m. High resolution bathymetry (multibeam) from 1997 and 2008 allow for subdivision of the west-central bayfloor into four basic types based on morphologic expression: featureless, sand waves, disrupted/man-altered, and bedrock knobs. Featureless and sand-wave morphologies dominate the bayfloor of west-central bay. Disrupted bayfloor has a direct association with areas that are undergoing alteration due to human activities, such as sand-mining lease areas, dredging, and disposal of dredge spoils. Change detection analysis, comparing the 1997 and 2008 multibeam data sets, shows that significant change has occurred in west-central bay during the roughly 10 years between surveys. The surveyed area lost about 5.45 million m3 of sediment during the decade. Sand-mining lease areas within west-central bay lost 6.77 million m3 as the bayfloor deepened. Nonlease areas gained 1.32 million m3 of sediment as the bayfloor shallowed slightly outside of sand-mining lease areas. Furthermore, bedform asymmetry did not change significantly, but some bedforms did migrate some tens of meters. Gravity cores show that the area east of Angel and Alcatraz Islands is floored by clayey silts or silty sand whereas the area to the west of the islands is floored

  20. Benthic flux of nutrients and trace metals in the northern component of San Francisco Bay, California

    Science.gov (United States)

    Kuwabara, James S.; Topping, Brent R.; Parcheso, Francis; Engelstad, Anita C.; Greene, Valerie E.

    2009-01-01

    Two sets of sampling trips were coordinated in late summer 2008 (weeks of July 8 and August 6) to sample the interstitial and overlying bottom waters at 10 shallow locations (9 sites Tiburon Center for Environmental Studies, provides information to assist in developing and refining management strategies for the Bay/Delta system and supports efforts to monitor changes in food-web structure associated with regional habitat modifications directed by the California Bay-Delta Authority. On July 7, 2008, and August 5, 2008, pore-water profilers were successfully deployed at six North Bay sites per trip to measure the concentration gradient of dissolved macronutrients and trace metals near the sediment-water interface. Only two of the sites (433 and SSB009 within Honker Bay) were sampled in both series of profiler deployments. At each sampling site, profilers were deployed in triplicate, while discrete samples and dataloggers were used to collect ancillary data from both the water column and benthos to help interpret diffusive-flux measurements. Benthic flux of dissolved (0.2-micron filtered) inorganic phosphate (that is, soluble reactive phosphorus (SRP)) ranged from negligible levels (-0.003?0.005 millimole per square meter per day (mmole m-2d-1) at Site 4.1 outside Honker Bay) to 0.060?0.006 mmole m-2d-1 near the northern coast of Brown?s Island. Except for the elevated flux at Browns Island, the benthic flux of soluble reactive phosphorus (SRP) was consistently: (1) lower than previously reported for South Bay sites, (2) an order of magnitude lower than oligotrophic Coeur d?Alene Lake, (3) two orders of magnitude lower than determined for eutrophic Upper Klamath Lake, and (4) an order of magnitude or more lower than the estimated summer riverine inputs for SRP (900 to 1,300 kilograms of phosphorous per day (kg-P d-1)). In contrast to fluxes reported for the South Bay, nitrate fluxes were consistently negative (that is, drawn from the water column into the sediment

  1. Environmental Sensitivity Index (ESI) Atlas: San Francisco Bay, California maps and geographic information systems data (NODC Accession 0013224)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set comprises the Environmental Sensitivity Index (ESI) maps for the shoreline of San Francisco Bay. ESI data characterize estuarine environments and...

  2. Salt Ponds, South San Francisco Bay

    Science.gov (United States)

    2002-01-01

    higher resolution 1000 pixel-wide image The red and green colors of the salt ponds in South San Francisco Bay are brilliant visual markers for astronauts. The STS-111 crew photographed the bay south of the San Mateo bridge in June, 2002. This photograph is timely because a large number of the salt ponds (more than 16,500 acres) that are owned by Cargill, Inc. will be sold in September for wetlands restoration-a restoration project second in size only to the Florida Everglades project. Rough boundaries of the areas to be restored are outlined on the image. Over the past century, more than 80% of San Francisco Bay's wetlands have been filled and developed or diked off for salt mining. San Francisco Bay has supported salt mining since 1854. Cargill has operated most of the bay's commercial salt ponds since 1978, and had already sold thousands of acres to the State of California and the Don Edwards National Wildlife Refuge. This new transaction will increase San Francisco Bay's existing tidal wetlands by 50%. The new wetlands, to be managed by the California Department of Fish and Game and the U.S. Fish and Wildlife Service, will join the Don Edwards National Wildlife Refuge, and provide valuable habitat for birds, fish and other wildlife. The wetlands will contribute to better water quality and flood control in the bay, and open up more coastline for public enjoyment. Additional information: Cargill Salt Ponds (PDF) Turning Salt Into Environmental Gold Salt Ponds on Way to Becoming Wetlands Historic Agreement Reached to Purchase San Francisco Bay Salt Ponds Astronaut photograph STS111-376-3 was provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth

  3. Understanding Urban Watersheds through Digital Interactive Maps, San Francisco Bay Area, California

    Science.gov (United States)

    Sowers, J. M.; Ticci, M. G.; Mulvey, P.

    2014-12-01

    Dense urbanization has resulted in the "disappearance" of many local creeks in urbanized areas surrounding the San Francisco Bay. Long reaches of creeks now flow in underground pipes. Municipalities and water agencies trying to reduce non-point-source pollution are faced with a public that cannot see and therefore does not understand the interconnected nature of the drainage system or its ultimate discharge to the bay. Since 1993, we have collaborated with the Oakland Museum, the San Francisco Estuary Institute, public agencies, and municipalities to create creek and watershed maps to address the need for public understanding of watershed concepts. Fifteen paper maps are now published (www.museumca.org/creeks), which have become a standard reference for educators and anyone working on local creek-related issues. We now present digital interactive creek and watershed maps in Google Earth. Four maps are completed covering urbanized areas of Santa Clara and Alameda Counties. The maps provide a 3D visualization of the watersheds, with cartography draped over the landscape in transparent colors. Each mapped area includes both Present and Past (circa 1800s) layers which can be clicked on or off by the user. The Present layers include the modern drainage network, watershed boundaries, and reservoirs. The Past layers include the 1800s-era creek systems, tidal marshes, lagoons, and other habitats. All data are developed in ArcGIS software and converted to Google Earth format. To ensure the maps are interesting and engaging, clickable icons pop-up provide information on places to visit, restoration projects, history, plants, and animals. Maps of Santa Clara Valley are available at http://www.valleywater.org/WOW.aspx. Maps of western Alameda County will soon be available at http://acfloodcontrol.org/. Digital interactive maps provide several advantages over paper maps. They are seamless within each map area, and the user can zoom in or out, and tilt, and fly over to explore

  4. Probabilistic Methodology for Estimation of Number and Economic Loss (Cost) of Future Landslides in the San Francisco Bay Region, California

    Science.gov (United States)

    Crovelli, Robert A.; Coe, Jeffrey A.

    2008-01-01

    The Probabilistic Landslide Assessment Cost Estimation System (PLACES) presented in this report estimates the number and economic loss (cost) of landslides during a specified future time in individual areas, and then calculates the sum of those estimates. The analytic probabilistic methodology is based upon conditional probability theory and laws of expectation and variance. The probabilistic methodology is expressed in the form of a Microsoft Excel computer spreadsheet program. Using historical records, the PLACES spreadsheet is used to estimate the number of future damaging landslides and total damage, as economic loss, from future landslides caused by rainstorms in 10 counties of the San Francisco Bay region in California. Estimates are made for any future 5-year period of time. The estimated total number of future damaging landslides for the entire 10-county region during any future 5-year period of time is about 330. Santa Cruz County has the highest estimated number of damaging landslides (about 90), whereas Napa, San Francisco, and Solano Counties have the lowest estimated number of damaging landslides (5?6 each). Estimated direct costs from future damaging landslides for the entire 10-county region for any future 5-year period are about US $76 million (year 2000 dollars). San Mateo County has the highest estimated costs ($16.62 million), and Solano County has the lowest estimated costs (about $0.90 million). Estimated direct costs are also subdivided into public and private costs.

  5. Integrated geomorphic and geodynamic modeling of a potential blind thrust in the San Francisco Bay area, California

    Science.gov (United States)

    Johnson, Courtney B.; Furlong, Kevin P.; Kirby, Eric

    2009-06-01

    Geometries and slip budgets of the faults in the San Francisco Bay area imply previously unrecognized fault linkages, including examples of blind thrust structures that appear to connect segments of strike-slip faults and accommodate along-strike variations in slip rate along these structures. Displacement along linking faults may be associated with the development of topography and also may serve as earthquake sources. In Marin County, California, systematic spatial patterns in landscape topography and geomorphic indices suggest that the region north of Mt. Tamalpais is experiencing differential rock uplift. We suggest that a blind thrust underlies the elevated area, creating the observed topography and possibly resolving a slip discrepancy between the Hayward and San Andreas Fault in this region. We have developed and implemented an integrative approach that combines observations from tectonic deformation and geomorphic properties to identify a potential blind thrust beneath Marin County. Elastic displacement modeling has been tested for compatibility with the blind thrust hypothesis and to assess the sensitivity of observables to fault geometry and orientation; from this, a set of plausible blind thrust structures are defined. We use a range of empirical relationships between channel steepness index and erosion rate to estimate spatial variations in erosion rate along Bolinas Ridge. By coupling these erosion estimates with elastic displacement fault modeling, we can use the resulting topographic envelopes to constrain the rate and duration of deformation. These constraints, along with spatial bounds on the possible fault models, are used to calculate potential seismic moment and moment magnitude. With an assumed recurrence interval of ~ 100 years, such blind thrusts can produce a Mw ~ 6.3 earthquake, while a longer recurrence time (~ 1000 years) results in a maximum Mw ~ 7.0 earthquake. Although such events are not likely to be catastrophic, they are large

  6. Earthquake stress drops and inferred fault strength on the Hayward Fault, east San Francisco Bay, California

    Science.gov (United States)

    Hardebeck, J.L.; Aron, A.

    2009-01-01

    We study variations in earthquake stress drop with respect to depth, faulting regime, creeping versus locked fault behavior, and wall-rock geology. We use the P-wave displacement spectra from borehole seismic recordings of M 1.0-4.2 earthquakes in the east San Francisco Bay to estimate stress drop using a stack-and-invert empirical Green's function method. The median stress drop is 8.7 MPa, and most stress drops are in the range between 0.4 and 130 MPa. An apparent correlation between stress drop and magnitude is entirely an artifact of the limited frequency band of 4-55 Hz. There is a trend of increasing stress drop with depth, with a median stress drop of ~5 MPa for 1-7 km depth, ~10 MPa for 7-13 km depth, and ~50 MPa deeper than 13 km. We use S=P amplitude ratios measured from the borehole records to better constrain the first-motion focal mechanisms. High stress drops are observed for a deep cluster of thrust-faulting earthquakes. The correlation of stress drops with depth and faulting regime implies that stress drop is related to the applied shear stress. We compare the spatial distribution of stress drops on the Hayward fault to a model of creeping versus locked behavior of the fault and find that high stress drops are concentrated around the major locked patch near Oakland. This also suggests a connection between stress drop and applied shear stress, as the locked patch may experience higher applied shear stress as a result of the difference in cumulative slip or the presence of higher-strength material. The stress drops do not directly correlate with the strength of the proposed wall-rock geology at depth, suggesting that the relationship between fault strength and the strength of the wall rock is complex.

  7. Humboldt Bay, California Benthic Habitats 2009 Substrate

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Humboldt Bay is the largest estuary in California north of San Francisco Bay and represents a significant resource for the north coast region. Beginning in 2007 the...

  8. Humboldt Bay, California Benthic Habitats 2009 Geoform

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Humboldt Bay is the largest estuary in California north of San Francisco Bay and represents a significant resource for the north coast region. Beginning in 2007 the...

  9. Humboldt Bay, California Benthic Habitats 2009 Geodatabase

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Humboldt Bay is the largest estuary in California north of San Francisco Bay and represents a significant resource for the north coast region. Beginning in 2007 the...

  10. Humboldt Bay, California Benthic Habitats 2009 Biotic

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Humboldt Bay is the largest estuary in California north of San Francisco Bay and represents a significant resource for the north coast region. Beginning in 2007 the...

  11. Identifying nest predators of American avocets (Recurvirostra americana) and black-necked stilts (Himantopus mexicanus) in San Francisco Bay, California

    Science.gov (United States)

    Herring, Garth; Ackerman, Joshua T.; Takekawa, John Y.; Eagles-Smith, Collin A.; Eadie, John M.

    2011-01-01

    We evaluated predation on nests and methods to detect predators using a combination of infrared cameras and plasticine eggs at nests of American avocets (Recurvirostra americana) and black-necked stilts (Himantopus mexicanus) in Don Edwards San Francisco Bay National Wildlife Refuge, San Mateo and Santa Clara counties, California. Each technique indicated that predation was prevalent; 59% of monitored nests were depredated. Most identifiable predation (n = 49) was caused by mammals (71%) and rates of predation were similar on avocets and stilts. Raccoons (Procyon lotor) and striped skunks (Mephitis mephitis) each accounted for 16% of predations, whereas gray foxes (Urocyon cinereoargenteus) and avian predators each accounted for 14%. Mammalian predation was mainly nocturnal (mean time, 0051 h +/- 5 h 36 min), whereas most avian predation was in late afternoon (mean time, 1800 h +/- 1 h 26 min). Nests with cameras and plasticine eggs were 1.6 times more likely to be predated than nests where only cameras were used in monitoring. Cameras were associated with lower abandonment of nests and provided definitive identification of predators.

  12. Storm surges and climate change implications for tidal marshes: Insight from the San Francisco Bay Estuary, California, USA

    Science.gov (United States)

    Thorne, Karen M.; Buffington, Kevin J.; Swanson, Kathleen; Takekawa, John Y.

    2013-01-01

    Tidal marshes are dynamic ecosystems, which are influenced by oceanic and freshwater processes and daily changes in sea level. Projected sea-level rise and changes in storm frequency and intensity will affect tidal marshes by altering suspended sediment supply, plant communities, and the inundation duration and depth of the marsh platform. The objective of this research was to evaluate if regional weather conditions resulting in low-pressure storms changed tidal conditions locally within three tidal marshes. We hypothesized that regional storms will increase sea level heights locally, resulting in increased inundation of the tidal marsh platform and plant communities. Using site-level measurements of elevation, plant communities, and water levels, we present results from two storm events in 2010 and 2011 from the San Francisco Bay Estuary (SFBE), California, USA. The January 2010 storm had the lowest recorded sea level pressure in the last 30 years for this region. During the storm episodes, the duration of tidal marsh inundation was 1.8 and 3.1 times greater than average for that time of year, respectively. At peak storm surges, over 65% in 2010 and 93% in 2011 of the plant community was under water. We also discuss the implications of these types of storms and projected sea-level rise on the structure and function of the tidal marshes and how that will impact the hydro-geomorphic processes and marsh biotic communities.

  13. Preliminary maps of Quaternary deposits and liquefaction susceptibility, nine-county San Francisco Bay region, California: a digital database

    Science.gov (United States)

    Knudsen, Keith L.; Sowers, Janet M.; Witter, Robert C.; Wentworth, Carl M.; Helley, Edward J.; Nicholson, Robert S.; Wright, Heather M.; Brown, Katherine H.

    2000-01-01

    This report presents a preliminary map and database of Quaternary deposits and liquefaction susceptibility for the nine-county San Francisco Bay region, together with a digital compendium of ground effects associated with past earthquakes in the region. The report consists of (1) a spatial database of fivedata layers (Quaternary deposits, quadrangle index, and three ground effects layers) and two text layers (a labels and leaders layer for Quaternary deposits and for ground effects), (2) two small-scale colored maps (Quaternary deposits and liquefaction susceptibility), (3) a text describing the Quaternary map, liquefaction interpretation, and the ground effects compendium, and (4) the databse description pamphlet. The nine counties surrounding San Francisco Bay straddle the San Andreas fault system, which exposes the region to serious earthquake hazard (Working Group on California Earthquake Probabilities, 1999). Much of the land adjacent to the Bay and the major rivers and streams is underlain by unconsolidated deposits that are particularly vulnerable to earthquake shaking and liquefaction of water-saturated granular sediment. This new map provides a modern and regionally consistent treatment of Quaternary surficial deposits that builds on the pioneering mapping of Helley and Lajoie (Helley and others, 1979) and such intervening work as Atwater (1982), Helley and others (1994), and Helley and Graymer (1997a and b). Like these earlier studies, the current mapping uses geomorphic expression, pedogenic soils, and inferred depositional environments to define and distinguish the map units. In contrast to the twelve map units of Helley and Lajoie, however, this new map uses a complex stratigraphy of some forty units, which permits a more realistic portrayal of the Quaternary depositional system. The two colored maps provide a regional summary of the new mapping at a scale of 1:275,000, a scale that is sufficient to show the general distribution and relationships of

  14. Estimating suspended solids concentrations from backscatter intensity measured by acoustic Doppler current profiler in San Francisco Bay, California

    Science.gov (United States)

    Gartner, J.W.

    2004-01-01

    The estimation of mass concentration of suspended solids is one of the properties needed to understand the characteristics of sediment transport in bays and estuaries. However, useful measurements or estimates of this property are often problematic when employing the usual methods of determination from collected water samples or optical sensors. Analysis of water samples tends to undersample the highly variable character of suspended solids, and optical sensors often become useless from biological fouling in highly productive regions. Acoustic sensors, such as acoustic Doppler current profilers that are now routinely used to measure water velocity, have been shown to hold promise as a means of quantitatively estimating suspended solids from acoustic backscatter intensity, a parameter used in velocity measurement. To further evaluate application of this technique using commercially available instruments, profiles of suspended solids concentrations are estimated from acoustic backscatter intensity recorded by 1200- and 2400-kHz broadband acoustic Doppler current profilers located at two sites in San Francisco Bay, California. ADCP backscatter intensity is calibrated using optical backscatterance data from an instrument located at a depth close to the ADCP transducers. In addition to losses from spherical spreading and water absorption, calculations of acoustic transmission losses account for attenuation from suspended sediment and correction for nonspherical spreading in the near field of the acoustic transducer. Acoustic estimates of suspended solids consisting of cohesive and noncohesive sediments are found to agree within about 8-10% (of the total range of concentration) to those values estimated by a second optical backscatterance sensor located at a depth further from the ADCP transducers. The success of this approach using commercially available Doppler profilers provides promise that this technique might be appropriate and useful under certain conditions in

  15. Sediment geochemistry of Corte Madera Marsh, San Francisco Bay, California: have local inputs changed, 1830-2010?

    Science.gov (United States)

    Takesue, Renee K.; Jaffe, Bruce E.

    2013-01-01

    Large perturbations since the mid-1800s to the supply and source of sediment entering San Francisco Bay have disturbed natural processes for more than 150 years. Only recently have sediment inputs through the Sacramento-San Joaquin Delta (the Delta) decreased to what might be considered pre-disturbance levels. Declining sediment inputs to San Francisco Bay raise concern about continued tidal marsh accretion, particularly if sea level rise accelerates in the future. The aim of this study is to explore whether the relative amount of local-watershed sediment accumulating in a tidal marsh has changed as sediment supply from the Sacramento-San Joaquin Rivers has decreased. To address this question, sediment geochemical indicators, or signatures, in the fine fraction (silt and clay) of Sacramento River, San Joaquin River, San Francisco Bay, and Corte Madera Creek sediment were identified and applied in sediment recovered from Corte Madera Marsh, one of the few remaining natural marshes in San Francisco Bay. Total major, minor, trace, and rare earth element (REE) contents of fine sediment were determined by inductively coupled plasma mass and atomic emission spectroscopy. Fine sediment from potential source areas had the following geochemical signatures: Sacramento River sediment downstream of the confluence of the American River was characterized by enrichments in chromium, zirconium, and heavy REE; San Joaquin River sediment at Vernalis and Lathrop was characterized by enrichments in thorium and total REE content; Corte Madera Creek sediment had elevated nickel contents; and the composition of San Francisco Bay mud proximal to Corte Madera Marsh was intermediate between these sources. Most sediment geochemical signatures were relatively invariant for more than 150 years, suggesting that the composition of fine sediment in Corte Madera Marsh is not very sensitive to changes in the magnitude, timing, or source of sediment entering San Francisco Bay through the Delta. Nor

  16. Late Quaternary depositional history, Holocene sea-level changes, and vertical crustal movement, southern San Francisco Bay, California

    Science.gov (United States)

    Atwater, Brian F.; Hedel, Charles W.; Helley, Edward J.

    1977-01-01

    Sediments collected for bridge foundation studies at southern San Francisco Bay, Calif., record estuaries that formed during Sangamon (100,000 years ago) and post-Wisconsin (less than 10,000 years ago) high stands of sea level. The estuarine deposits of Sangamon and post-Wisconsin ages are separated by alluvial and eolian deposits and by erosional unconformities and surfaces of nondeposition, features that indicate lowered base levels and oceanward migrations of the shoreline accompanying low stands of the sea. Estuarine deposits of mid-Wisconsin age appear to be absent, suggesting that sea level was not near its present height 30,000–40,000 years ago in central California. Holocene sea-level changes are measured from the elevations and apparent 14C ages of plant remains from 13 core samples. Uncertainties of ±2 to ±4 m in the elevations of the dated sea levels represent the sum of errors in determination of (1) sample elevation relative to present sea level, (2) sample elevation relative to sea level at the time of accumulation of the dated material, and (3) postdepositional subsidence of the sample due to compaction of underlying sediments. Sea level in the vicinity of southern San Francisco Bay rose about 2 cm/yr from 9,500 to 8,000 years ago. The rate of relative sea-level rise then declined about tenfold from 8,000 to 6,000 years ago, and it has averaged 0.1–0.2 cm/yr from 6,000 years ago to the present. This submergence history indicates that the rising sea entered the Golden Gate 10,000–11,000 years ago and spread across land areas as rapidly as 30 m/yr until 8,000 years ago. Subsequent shoreline changes were more gradual because of the decrease in rate of sea-level rise. Some of the sediments under southern San Francisco Bay appear to be below the level at which they initially accumulated. The vertical crustal movement suggested by these sediments may be summarized as follows: (1) Some Quaternary(?) sediments have sustained at least 100 m of

  17. Late 20th Century benthic foraminiferal distribution in Central San Francisco Bay, California: Influence of the Trochammina hadai invasion

    Science.gov (United States)

    McGann, Mary L.

    2014-01-01

    The distribution of foraminifera in most of San Francisco Bay is well documented, but this is not the case for the subembayment known as Central Bay. To resolve this, 55 grab samples obtained in 1998 were analyzed to characterize the foraminiferal fauna in the surface sediments of the area. Thirty-five species were identified, including the invasive Japanese species Trochammina hadai that was introduced into the bay in the early 1980s. A cluster analysis of the samples from Central Bay produced three groups (biofacies) and one outlier. The Shallow Subtidal Biofacies is characterized by a marsh to shallow-subtidal agglutinated fauna, dominated by T. hadai but also including T. inflata, T. macrescens, Haplophragmoides subinvolutum, and Miliammina fusca. The Intermediate Subtidal Biofacies, the Intermediate Subtidal Outlier, and the Deep Subtidal Biofacies are dominated by calcareous taxa, most notably Ammonia tepida, Elphidium excavatum, and Elphidiella hannai. Ammonia tepida is most abundant in the warmer, intermediate depths of eastern Central Bay, abundances of E. excavatum peak in the cooler estuarine water near Alcatraz Island, and E. hannai thrives in the cold water west of Angel Island in a transitional setting between the deep subtidal estuarine and the nearshore marine environments. The recovery of oceanic species as far east as Angel Island indicate that western Central Bay is the most marine-influenced region of San Francisco Bay.

  18. Summary of California Clapper Rail Winter Populations in the San Francisco Bay, 1989 to 1993

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The federal and state endangered California clapper rail, Rallus longirostris obsoletus. is a species that, until very recently, was on the verge of extinction. This...

  19. Seismic-reflection evidence that the hayward fault extends into the lower crust of the San Francisco Bay Area, California

    Science.gov (United States)

    Parsons, T.

    1998-01-01

    This article presents deep seismic-reflection data from an experiment across San Francisco Peninsula in 1995 using large (125 to 500 kg) explosive sources. Shot gathers show a mostly nonreflective upper crust in both the Franciscan and Salinian terranes (juxtaposed across the San Andreas fault), an onset of weak lower-crustal reflectivity beginning at about 6-sec two-way travel time (TWTT) and bright southwest-dipping reflections between 11 and 13 sec TWTT. Previous studies have shown that the Moho in this area is no deeper than 25 km (~8 to 9 sec TWTT). Three-dimensional reflection travel-time modeling of the 11 to 13 sec events from the shot gathers indicates that the bright events may be explained by reflectors 15 to 20 km into the upper mantle, northeast of the San Andreas fault. However, upper mantle reflections from these depths were not observed on marine-reflection profiles collected in San Francisco Bay, nor were they reported from a refraction profile on San Francisco Peninsula. The most consistent interpretation of these events from 2D raytracing and 3D travel-time modeling is that they are out-of-plane reflections from a high-angle (dipping ~70??to the southwest) impedance contrast in the lower crust that corresponds with the surface trace of the Hayward fault. These results suggest that the Hayward fault truncates the horizontal detachment fault suggested to be active beneath San Francisco Bay.

  20. Ground-Water Quality Data in the San Francisco Bay Study Unit, 2007: Results from the California GAMA Program

    Science.gov (United States)

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

    2009-01-01

    Ground-water quality in the approximately 620-square-mile San Francisco Bay study unit (SFBAY) was investigated from April through June 2007 as part of the Priority Basin project of the Ground-Water Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin project was developed in response to the Groundwater Quality Monitoring Act of 2001, and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The study was designed to provide a spatially unbiased assessment of raw ground-water quality, as well as a statistically consistent basis for comparing water quality throughout California. Samples in SFBAY were collected from 79 wells in San Francisco, San Mateo, Santa Clara, Alameda, and Contra Costa Counties. Forty-three of the wells sampled were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study unit (grid wells). Thirty-six wells were sampled to aid in evaluation of specific water-quality issues (understanding wells). The ground-water samples were analyzed for a large number of synthetic organic constituents (volatile organic compounds [VOC], pesticides and pesticide degradates, pharmaceutical compounds, and potential wastewater-indicator compounds), constituents of special interest (perchlorate and N-nitrosodimethylamine [NDMA]), naturally occurring inorganic constituents (nutrients, major and minor ions, trace elements, chloride and bromide isotopes, and uranium and strontium isotopes), radioactive constituents, and microbial indicators. Naturally occurring isotopes (tritium, carbon-14 isotopes, and stable isotopes of hydrogen, oxygen, nitrogen, boron, and carbon), and dissolved noble gases (noble gases were analyzed in collaboration with Lawrence Livermore National Laboratory) also were measured to help identify the source and age of the sampled ground water. Quality-control samples (blank samples

  1. Geology, geochronology, and paleogeography of the southern Sonoma volcanic field and adjacent areas, northern San Francisco Bay region, California

    Science.gov (United States)

    Wagner, D.L.; Saucedo, G.J.; Clahan, K.B.; Fleck, R.J.; Langenheim, V.E.; McLaughlin, R.J.; Sarna-Wojcicki, A. M.; Allen, J.R.; Deino, A.L.

    2011-01-01

    Recent geologic mapping in the northern San Francisco Bay region (California, USA) supported by radiometric dating and tephrochronologic correlations, provides insights into the framework geology, stratigraphy, tectonic evolution, and geologic history of this part of the San Andreas transform plate boundary. There are 25 new and existing radiometric dates that define three temporally distinct volcanic packages along the north margin of San Pablo Bay, i.e., the Burdell Mountain Volcanics (11.1 Ma), the Tolay Volcanics (ca. 10-8 Ma), and the Sonoma Volcanics (ca. 8-2.5 Ma). The Burdell Mountain and the Tolay Volcanics are allochthonous, having been displaced from the Quien Sabe Volcanics and the Berkeley Hills Volcanics, respectively. Two samples from a core of the Tolay Volcanics taken from the Murphy #1 well in the Petaluma oilfield yielded ages of 8.99 ?? 0.06 and 9.13 ?? 0.06 Ma, demonstrating that volcanic rocks exposed along Tolay Creek near Sears Point previously thought to be a separate unit, the Donnell Ranch volcanics, are part of the Tolay Volcanics. Other new dates reported herein show that volcanic rocks in the Meacham Hill area and extending southwest to the Burdell Mountain fault are also part of the Tolay Volcanics. In the Sonoma volcanic field, strongly bimodal volcanic sequences are intercalated with sediments. In the Mayacmas Mountains a belt of eruptive centers youngs to the north. The youngest of these volcanic centers at Sugarloaf Ridge, which lithologically, chemically, and temporally matches the Napa Valley eruptive center, was apparently displaced 30 km to the northwest by movement along the Carneros and West Napa faults. The older parts of the Sonoma Volcanics have been displaced at least 28 km along the RodgersCreek fault since ca. 7 Ma. The Petaluma Formation also youngs to the north along the Rodgers Creek-Hayward fault and the Bennett Valley fault. The Petaluma basin formed as part of the Contra Costa basin in the Late Miocene and was

  2. High-resolution foraminiferal, isotopic, and trace element records from holocene estuarine deposits of San Francisco Bay, California

    Science.gov (United States)

    McGann, M.

    2008-01-01

    Ice Age (LIA I and LIA II) is evident from 650 to 280 cal YBP, with the return of the E. excavatum association and an extreme drop in ??18O values, all indicating increased precipitation and fresh water inflow. This was followed by generally drier conditions to the present, except for a brief wet period around 100 cal YBP, and fairly consistent water temperatures in the middle 13??C, except for a drop to 12.8??C at 200 cal YBP. Two significant faunal changes occur near the top of the core. First, there is the reappearance of the A. beccarii-E. gunteri association, suggesting that, once again, regional warming has taken place, oxygen availability has declined, and/or environmental conditions changed such that diatoms have become a scarce food source. Second, there is the first appearance of the invasive Japanese foraminifera Trochammina hadai Uchio, a species that commonly lives in highly polluted areas and is an indicator of eutrophication in its native estuaries. At the same time, freshwater inflow decreased, which may be explained by global warming during the last 100 years, or more likely due to modern water diversion for agriculture in the central valley of California. ADDITIONAL INDEX WORDS: Climate, San Francisco Bay, Holocene, foraminifers, isotopes, trace metals, Medieval Warm Period, Little Ice Age.

  3. Data from theodolite measurements of creep rates on San Francisco Bay region faults, California: 1979-2001

    Science.gov (United States)

    Galehouse, Jon S.

    2002-01-01

    My purpose is to make our creep data on San Francisco Bay region active faults available to the scientific research community. My student research assistants and I measured creep (aseismic slip) rates on these faults from 1979 until my retirement from the project in 2001. These data are further described in my final technical report as principal investigator, which summarizes results from 22 September 1979 through 28 February 2001 (Galehouse, 2001). We made over 2,600 creep measurements, about one-third in the ten years prior to the Loma Prieta earthquake (LPEQ) and two-thirds in the 11.4 years following it. The measurements are continuing to be made by members of the Geosciences Department at San Francisco State University (SFSU) under the direction of Karen Grove and John Caskey. A complete analysis of our results obtained on the Hayward fault is presented in Lienkaemper, Galehouse, and Simpson (2001). A formal report based on the entire San Francisco Bay region data set is in preparation. Data sheets for each site along the fault are available for downloading in Excel format to facilitate analysis of the data. They are also available as tab-delimited raw data. The data include all regular measurement sites, SF–1 through SF–34, and the 20 SFSU and U.S. Geological Survey (USGS) afterslip sites on the Hayward fault.

  4. GPS Instrumentation and Remote Sensing Study of Slow Moving Landslides in the Eastern San Francisco Bay Hills, California, USA

    Science.gov (United States)

    Cohen-Waeber, J.; Burgmann, R.; Sitar, N.; Ferretti, A.; Giannico, C.

    2012-12-01

    The objective of this study is to characterize slope deformation as a result of static and dynamic forces, using the most current geodetic technologies that measure active ground surface displacement. Recent advances in geodetic and remote data collection, such as with continuous GPS and Interferometric Synthetic Aperture Radar (InSAR) allow for a level of primary site characterization and eventual risk assessment due to landsliding that was previously not possible. Active landsliding across the Lawrence Berkeley National Laboratory (LBNL) site and the greater Berkeley Hills region, in the Eastern San Francisco Bay, California, has been the object of many investigations over recent decades, though the mechanisms of currently mobile slides are still poorly understood. Previous studies suggest a trend in landslide mobility is closely associated with precipitation and regional active tectonic conditions in addition to the geologic setting (Alan Kropp and Associates, 2002). InSAR time-series analysis has been shown to successfully track creeping landslides in the Berkeley Hills with millimeter scale accuracy (Hilley et al., 2004) and documents displacement primarily during periods of high precipitation (Quigley et al., 2010). However, displacement of creeping landslides due to seismic activity has yet to be measured. A first focus of this project is therefore to study the spatial and temporal distribution of active Berkeley Hills landsliding in relation to local precipitation and ground shaking events by a careful observational program. This program includes the instrumentation of individual landslides with permanent continuously streaming GPS stations (beginning 2012), and regional monitoring of slope surface deformation by InSAR time series analysis (beginning 1992). To date, continuous GPS tracking of select landslides has recorded up to 2 cm of total surface deformation driven by the onset of precipitation, with displacement response times of less than 5 days

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

    Science.gov (United States)

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

    2013-01-01

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

  6. Seismotectonic Implications Of Clustered Regional GPS Velocities In The San Francisco Bay Region, California

    Science.gov (United States)

    Graymer, R. W.; Simpson, R.

    2012-12-01

    We have used a hierarchical agglomerative clustering algorithm with Euclidean distance and centroid linkage, applied to continuous GPS observations for the Bay region available from the U.S. Geological Survey website. This analysis reveals 4 robust, spatially coherent clusters that coincide with 4 first-order structural blocks separated by 3 major fault systems: San Andreas (SA), Southern/Central Calaveras-Hayward-Rodgers Creek-Maacama (HAY), and Northern Calaveras-Concord-Green Valley-Berryessa-Bartlett Springs (NCAL). Because observations seaward of the San Gregorio (SG) fault are few in number, the cluster to the west of SA may actually contain 2 major structural blocks not adequately resolved: the Pacific plate to the west of the northern SA and a Peninsula block between the Peninsula SA and the SG fault. The average inter-block velocities are 11, 10, and 9 mm/yr across SA, HAY, and NCAL respectively. There appears to be a significant component of fault-normal compression across NCAL, whereas SA and HAY faults appear to be, on regional average, purely strike-slip. The velocities for the Sierra Nevada - Great Valley (SNGV) block to the west of NCAL are impressive in their similarity. The cluster of these velocities in a velocity plot forms a tighter grouping compared with the groupings for the other cluster blocks, suggesting a more rigid behavior for this block than the others. We note that for 4 clusters, none of the 3 cluster boundaries illuminate geologic structures other than north-northwest trending dominantly strike-slip faults, so plate motion is not accommodated by large-scale fault-parallel compression or extension in the region or by significant plastic deformation , at least over the time span of the GPS observations. Complexities of interseismic deformation of the upper crust do not allow simple application of inter-block velocities as long-term slip rates on bounding faults. However, 2D dislocation models using inter-block velocities and typical

  7. Operation of a real-time warning system for debris flows in the San Francisco bay area, California

    Science.gov (United States)

    Wilson, Raymond C.; Mark, Robert K.; Barbato, Gary; ,

    1993-01-01

    The United States Geological Survey (USGS) and the National Weather Service (NWS) have developed an operational warning system for debris flows during severe rainstorms in the San Francisco Bay region. The NWS makes quantitative forecasts of precipitation from storm systems approaching the Bay area and coordinates a regional network of radio-telemetered rain gages. The USGS has formulated thresholds for the intensity and duration of rainfall required to initiate debris flows. The first successful public warnings were issued during a severe storm sequence in February 1986. Continued operation of the warning system since 1986 has provided valuable working experience in rainfall forecasting and monitoring, refined rainfall thresholds, and streamlined procedures for issuing public warnings. Advisory statements issued since 1986 are summarized.

  8. A Breeding Season Survey of the California Clapper Rail (Rallus longirostritis obsoletus) in South San Francisco Bay, California

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The purpose of this project was to determine the densities and nesting success, and to investigate the habitat requirements of California Clapper Rails breeding in...

  9. Groundwater-quality data in the North San Francisco Bay Shallow Aquifer study unit, 2012: results from the California GAMA Program

    Science.gov (United States)

    Bennett, George L.; Fram, Miranda S.

    2014-01-01

    Groundwater quality in the 1,850-square-mile North San Francisco Bay Shallow Aquifer (NSF-SA) study unit was investigated by the U.S. Geological Survey (USGS) from April to August 2012, as part of the California State Water Resources Control Board (SWRCB) Groundwater Ambient Monitoring and Assessment (GAMA) Program’s Priority Basin Project (PBP). The GAMA-PBP was developed in response to the California Groundwater Quality Monitoring Act of 2001 and is being conducted in collaboration with the SWRCB and Lawrence Livermore National Laboratory (LLNL). The NSF-SA study unit was the first study unit to be sampled as part of the second phase of the GAMA-PBP, which focuses on the shallow aquifer system.

  10. 2010 Northern San Francisco Bay Area Lidar: Portions of Alameda, Contra Costa, Marin, Napa, San Francisco, Solano, and Sonoma Counties

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This Light Detection and Ranging (LiDAR) dataset is a survey of northern San Francisco Bay, California. The project area consists of approximately 437 square miles...

  11. 2010 Northern San Francisco Bay Area Lidar: Portions of Alameda, Contra Costa, Marin, Napa, San Francisco, Solano, and Sonoma Counties

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This Light Detection and Ranging (LiDAR) dataset is a survey of northern San Francisco Bay, California. The project area consists of approximately 437 square miles...

  12. A Global Talent Magnet: How a San Francisco/Bay Area Global Higher Education Hub Could Advance California's Comparative Advantage in Attracting International Talent and Further Build US Economic Competitiveness. Research & Occasional Paper Series: CSHE.9.11

    Science.gov (United States)

    Douglass, John; Edelstein, Richard; Hoareau, Cecile

    2011-01-01

    During the 2009-10 academic year international students generated more than $18.8 billion in net income into the US economy. California alone had nearly 100,000 international students with an economic impact of nearly $3.0 billion. In this paper, we outline a strategy for the San Francisco/Bay Area to double the number of international students…

  13. Data from theodolite measurements of creep rates on San Francisco Bay region faults, California, 1979-2012

    Science.gov (United States)

    McFarland, Forrest S.; Lienkaemper, James J.; Caskey, S. John

    2009-01-01

    Our purpose is to annually update our creep-data archive on San Francisco Bay region active faults for use by the scientific research community. Earlier data (1979-2001) were reported in Galehouse (2002) and were analyzed and described in detail in a summary report (Galehouse and Lienkaemper, 2003). A complete analysis of our earlier results obtained on the Hayward Fault was presented in Lienkaemper, Galehouse and Simpson (2001) and updated in Lienkaemper and others (2012). Lienkaemper and others (2014a) provide a new overview and analysis of fault creep along all sections of the northern San Andreas Fault system, from which they estimate by how much fault creep reduces the seismic hazard for each fault section.

  14. The San Andreas fault in the San Francisco Bay region, California: Structure and kinematics of a Young plate boundary

    Science.gov (United States)

    Jachens, R.C.; Zoback, M.L.

    1999-01-01

    Recently acquired high-resolution aeromagnetic data delineate offset and/or truncated magnetic rock bodies of the Franciscan Complex that define the location and structure of, and total offset across, the San Andreas fault in the San Francisco Bay region. Two distinctive magnetic anomalies caused by ultramafic rocks and metabasalts east of, and truncated at, the San Andreas fault have clear counterparts west of the fault that indicate a total right-lateral offset of only 22 km on the Peninsula segment, the active strand that ruptured in 1906. The location of the Peninsula segment is well defined magnetically on the northern peninsula where it goes offshore, and can be traced along strike an additional ~6 km to the northwest. Just offshore from Lake Merced, the inferred fault trace steps right (northeast) 3 km onto a nearly parallel strand that can be traced magnetically northwest more than 20 km as the linear northeast edge of a magnetic block bounded by the San Andreas fault, the Pilarcitos fault, and the San Gregorio-Hosgri fault zone. This right-stepping strand, the Golden Gate segment, joins the eastern mapped trace of the San Andreas fault at Bolinas Lagoon and projects back onshore to the southeast near Lake Merced. Inversion of detailed gravity data on the San Francisco Peninsula reveals a 3 km wide basin situated between the two strands of the San Andreas fault, floored by Franciscan basement and filled with Plio-Quaternary sedimentary deposits of the Merced and Colma formations. The basin, ~1 km deep at the coast, narrows and becomes thinner to the southeast along the fault over a distance of ~12 km. The length, width, and location of the basin between the two strands are consistent with a pull-apart basin formed behind the right step in the right-lateral strike-slip San Andreas fault system and currently moving southeast with the North American plate. Slight nonparallelism of the two strands bounding the basin (implying a small component of convergence

  15. Dissolved Oxygen in Guadalupe Slough and Pond A3W, South San Francisco Bay, California, August and September 2007

    Science.gov (United States)

    Shellenbarger, Gregory; Schoellhamer, David H.; Morgan, Tara L.; Takekawa, John Y.; Athearn, Nicole D.; Henderson, Kathleen D.

    2008-01-01

    Initial restoration of former salt evaporation ponds under the South Bay Salt Pond Restoration Project in San Francisco Bay included the changing of water-flow patterns and the monitoring of water quality of discharge waters from the ponds. Low dissolved oxygen (DO) concentrations became evident in discharge waters when the ponds first were opened in 2004. This was a concern, because of the potential for low-DO pond discharge to decrease the DO concentrations in the sloughs that receive water from the ponds. However, as of summer 2007, only limited point-measurements of DO concentrations had been made in the receiving sloughs adjacent to the discharge ponds. In this report, we describe two short studies aimed at understanding the natural variability of slough DO and the effect of pond discharge on the DO concentrations in the sloughs. Pond A3W (a discharge pond) and the adjacent Guadalupe Slough were instrumented in August and September 2007 to measure DO, temperature, conductivity, and pH. In addition, Mowry and Newark Sloughs were instrumented during the August study to document DO variability in nearby sloughs that were unaffected by pond discharge. The results showed that natural tidal variability in the slough appeared to dominate and control the slough DO concentrations. Water-quality parameters between Guadalupe Slough and Mowry and Newark Sloughs could not be directly compared because deployment locations were different distances from the bay. Pond-discharge water was identified in Guadalupe Slough using the deployed instruments, but, counter to the previous assumption, the pond discharge, at times, increased DO concentrations in the slough. The effects of altering the volume of pond discharge were overwhelmed by natural spring-neap tidal variability in the slough. This work represents a preliminary investigation by the U.S. Geological Survey of the effects of pond discharge on adjacent sloughs, and the results will be used in designing a comprehensive DO

  16. Data from Theodolite Measurements of Creep Rates on San Francisco Bay Region Faults, California: 1979-2007

    Science.gov (United States)

    McFarland, Forrest S.; Lienkaemper, James J.; Caskey, S. John; Grove, Karen

    2007-01-01

    Introduction Our purpose is to update with six additional years of data, our creep data archive on San Francisco Bay region active faults for use by the scientific research community. Earlier data (1979-2001) were reported in Galehouse (2002) and were analyzed and described in detail in a summary report (Galehouse and Lienkaemper, 2003). A complete analysis of our earlier results obtained on the Hayward fault was presented in Lienkaemper, Galehouse and Simpson (2001). Jon Galehouse of San Francisco State University (SFSU) and many student research assistants measured creep (aseismic slip) rates on these faults from 1979 until his retirement from the project in 2001. The creep measurement project, which was initiated by Galehouse, has continued through the Geosciences Department at SFSU from 2001-2006 under the direction of Co-P.I.'s Karen Grove and John Caskey (Grove and Caskey, 2005), and by Caskey since 2006. Forrest McFarland has managed most of the technical and logistical project operations as well as data processing and compilation since 2001. We plan to publish detailed analyses of these updated creep data in future publications. We maintain a project web site (http://funnel.sfsu.edu/creep/) that includes the following information: project description, project personnel, creep characteristics and measurement, map of creep measurement sites, creep measurement site information, and data plots for each measurement site. Our most current, annually updated results are therefore accessible to the scientific community and to the general public. Information about the project can currently be requested by the public by an email link (fltcreep@sfsu.edu) found on our project website.

  17. Landslides, Floods, and Marine Effects of the Storm of January 3-5, 1982, in the San Francisco Bay Region, California

    Science.gov (United States)

    Ellen, Stephen D.; Wieczorek, Gerald F.

    1988-01-01

    A catastrophic rainstorm in central California on January 3-5,1982, dropped as much as half the mean annual precipitation within a period of about 32 hours, triggering landslides and floods throughout 10 counties in the vicinity of the San Francisco Bay. More than 18,000 of the slides induced by the storm transformed into debris flows that swept down hillslopes or drainages with little warning. Debris flows damaged at least 100 homes, killed 14 residents, and carried a 15th victim into a creek. Shortly after rainfall ceased, more than 459,000 m3 of earth and rock slid from a mountainside above the community of Love Creek in Santa Cruz County, burying 10 people in their homes. Throughout the bay region, thousands of people vacated homes in hazardous areas, entire communities were isolated as roads were blocked, public water systems were destroyed, and power and telephone services were disrupted. Altogether, the storm damaged 6,300 homes, 1,500 businesses, and tens of kilometers of roads, bridges, and communication lines. Preliminary rough estimates of total storm damage, compiled for emergency purposes within 2 weeks of the storm, exceeded $280 million. Carefully documented direct costs from landslides exceeded $66 million; total costs from landslides certainly were greater and probably constituted a much larger proportion of the total storm damage than suggested by these disparate figures. Landslides accounted for 25 of the 33 deaths attributed to the storm.

  18. Stream Habitat Reach Summary - San Francisco Bay, Central Coast [ds159

    Data.gov (United States)

    California Department of Resources — The Stream Habitat - San Francisco Bay, Central and South Coasts [ds159] shapefile contains four years of in-stream salmonid habitat data at the reach level. The...

  19. Greenhouse Gas (GHG) Source Detection and Attribution in the San Francisco Bay Area of California Using a Mobile Measurement Platform

    Science.gov (United States)

    Guha, A.; Bower, J.; Martien, P. T.; Perkins, I.; Randall, S.; Stevenson, E.; Young, A.; Hilken, H.

    2016-12-01

    The Bay Area Air Quality Management District is the greater San Francisco Bay metropolitan area's chief air quality regulatory agency. Aligning itself with the Governor's Executive Order S-3-05, the Air District has set a goal to reduce the region's GHG emissions by 80% below 1990 levels by the year 2050. The Air District's 2016 Clean Air Plan will lay out the agency's vision and actions to put the region on a path forward towards achieving the 2050 goal while also reducing air pollution and related health impacts. The 2016 Plan has three overarching objectives: 1) develop a multi-pollutant emissions control strategy, (2) reduce population exposure to harmful air pollutants, especially in vulnerable communities, and (3) protect climate through a comprehensive Regional Climate Protection Strategy. To accomplish one of 2016 Plan's control measures (SL3 - Greenhouse Gas Monitoring and Measurement Network), the Air District has fabricated a mobile measurement platform i.e. a GHG research van to perform targeted CH4 emissions hotspot detection and source attribution. The van is equipped with analyzers capable of measuring CH4, CO2 and N2O in ambient plumes at fast sampling rates. The coincident measurement of source tracers like isotopic methane (13C - CH4), CO and ethane (C2H6) provide the capability to distinguish between biogenic, combustion-based and fossil-based fugitive methane sources, respectively. The GHG research van is a comprehensive mobile tool to perform tracer-based GHG source identification and apportionment. We report observation-based source-specific tracer-to-tracer emission ratios from a region-wide survey of well-known area sources like landfills, wastewater treatment facilities and dairies, and compare those with similar ratios in the Air District's GHG inventory. We also investigate plumes from potentially under-inventoried sources like anaerobic digesters, composting operations, active and plugged oil and gas wells, and a natural gas storage

  20. Phytoplankton bloom dynamics in coastal ecosystems: A review with some general lessons from sustained investigation of San Francisco Bay, California

    Science.gov (United States)

    Cloern, James E.

    1996-05-01

    Phytoplankton blooms are prominent features of biological variability in shallow coastal ecosystems such as estuaries, lagoons, bays, and tidal rivers. Long-term observation and research in San Francisco Bay illustrates some patterns of phytoplankton spatial and temporal variability and the underlying mechanisms of this variability. Blooms are events of rapid production and accumulation of phytoplankton biomass that are usually responses to changing physical forcings originating in the coastal ocean (e.g., tides), the atmosphere (wind), or on the land surface (precipitation and river runoff). These physical forcings have different timescales of variability, so algal blooms can be short-term episodic events, recurrent seasonal phenomena, or rare events associated with exceptional climatic or hydrologic conditions. The biogeochemical role of phytoplankton primary production is to transform and incorporate reactive inorganic elements into organic forms, and these transformations are rapid and lead to measurable geochemical change during blooms. Examples include the depletion of inorganic nutrients (N, P, Si), supersaturation of oxygen and removal of carbon dioxide, shifts in the isotopic composition of reactive elements (C, N), production of climatically active trace gases (methyl bromide, dimethylsulfide), changes in the chemical form and toxicity of trace metals (As, Cd, Ni, Zn), changes in the biochemical composition and reactivity of the suspended particulate matter, and synthesis of organic matter required for the reproduction and growth of heterotrophs, including bacteria, zooplankton, and benthic consumer animals. Some classes of phytoplankton play special roles in the cycling of elements or synthesis of specific organic molecules, but we have only rudimentary understanding of the forces that select for and promote blooms of these species. Mounting evidence suggests that the natural cycles of bloom variability are being altered on a global scale by human

  1. Projected evolution of California's San Francisco Bay-Delta-river system in a century of climate change.

    Directory of Open Access Journals (Sweden)

    James E Cloern

    Full Text Available BACKGROUND: Accumulating evidence shows that the planet is warming as a response to human emissions of greenhouse gases. Strategies of adaptation to climate change will require quantitative projections of how altered regional patterns of temperature, precipitation and sea level could cascade to provoke local impacts such as modified water supplies, increasing risks of coastal flooding, and growing challenges to sustainability of native species. METHODOLOGY/PRINCIPAL FINDINGS: We linked a series of models to investigate responses of California's San Francisco Estuary-Watershed (SFEW system to two contrasting scenarios of climate change. Model outputs for scenarios of fast and moderate warming are presented as 2010-2099 projections of nine indicators of changing climate, hydrology and habitat quality. Trends of these indicators measure rates of: increasing air and water temperatures, salinity and sea level; decreasing precipitation, runoff, snowmelt contribution to runoff, and suspended sediment concentrations; and increasing frequency of extreme environmental conditions such as water temperatures and sea level beyond the ranges of historical observations. CONCLUSIONS/SIGNIFICANCE: Most of these environmental indicators change substantially over the 21(st century, and many would present challenges to natural and managed systems. Adaptations to these changes will require flexible planning to cope with growing risks to humans and the challenges of meeting demands for fresh water and sustaining native biota. Programs of ecosystem rehabilitation and biodiversity conservation in coastal landscapes will be most likely to meet their objectives if they are designed from considerations that include: (1 an integrated perspective that river-estuary systems are influenced by effects of climate change operating on both watersheds and oceans; (2 varying sensitivity among environmental indicators to the uncertainty of future climates; (3 inevitability of

  2. Projected evolution of California's San Francisco bay-delta-river system in a century of climate change

    Science.gov (United States)

    Cloern, J.E.; Knowles, N.; Brown, L.R.; Cayan, D.; Dettinger, M.D.; Morgan, T.L.; Schoellhamer, D.H.; Stacey, M.T.; van der Wegen, M.; Wagner, R.W.; Jassby, A.D.

    2011-01-01

    Background: Accumulating evidence shows that the planet is warming as a response to human emissions of greenhouse gases. Strategies of adaptation to climate change will require quantitative projections of how altered regional patterns of temperature, precipitation and sea level could cascade to provoke local impacts such as modified water supplies, increasing risks of coastal flooding, and growing challenges to sustainability of native species. Methodology/Principal Findings: We linked a series of models to investigate responses of California's San Francisco Estuary-Watershed (SFEW) system to two contrasting scenarios of climate change. Model outputs for scenarios of fast and moderate warming are presented as 2010-2099 projections of nine indicators of changing climate, hydrology and habitat quality. Trends of these indicators measure rates of: increasing air and water temperatures, salinity and sea level; decreasing precipitation, runoff, snowmelt contribution to runoff, and suspended sediment concentrations; and increasing frequency of extreme environmental conditions such as water temperatures and sea level beyond the ranges of historical observations. Conclusions/Significance: Most of these environmental indicators change substantially over the 21st century, and many would present challenges to natural and managed systems. Adaptations to these changes will require flexible planning to cope with growing risks to humans and the challenges of meeting demands for fresh water and sustaining native biota. Programs of ecosystem rehabilitation and biodiversity conservation in coastal landscapes will be most likely to meet their objectives if they are designed from considerations that include: (1) an integrated perspective that river-estuary systems are influenced by effects of climate change operating on both watersheds and oceans; (2) varying sensitivity among environmental indicators to the uncertainty of future climates; (3) inevitability of biological community

  3. Projected evolution of California's San Francisco Bay-Delta-River System in a century of continuing climate change

    Science.gov (United States)

    Cloern, James E.; Knowles, Noah; Brown, Larry R.; Cayan, Daniel; Dettinger, Michael D.; Morgan, Tara L.; Schoellhamer, David H.; Stacey, Mark T.; van der Wegen, Mick; Wagner, R. Wayne; Jassby, Alan D.

    2011-01-01

    Background Accumulating evidence shows that the planet is warming as a response to human emissions of greenhouse gases. Strategies of adaptation to climate change will require quantitative projections of how altered regional patterns of temperature, precipitation and sea level could cascade to provoke local impacts such as modified water supplies, increasing risks of coastal flooding, and growing challenges to sustainability of native species. Methodology/Principal Findings We linked a series of models to investigate responses of California's San Francisco Estuary-Watershed (SFEW) system to two contrasting scenarios of climate change. Model outputs for scenarios of fast and moderate warming are presented as 2010–2099 projections of nine indicators of changing climate, hydrology and habitat quality. Trends of these indicators measure rates of: increasing air and water temperatures, salinity and sea level; decreasing precipitation, runoff, snowmelt contribution to runoff, and suspended sediment concentrations; and increasing frequency of extreme environmental conditions such as water temperatures and sea level beyond the ranges of historical observations. Conclusions/Significance Most of these environmental indicators change substantially over the 21st century, and many would present challenges to natural and managed systems. Adaptations to these changes will require flexible planning to cope with growing risks to humans and the challenges of meeting demands for fresh water and sustaining native biota. Programs of ecosystem rehabilitation and biodiversity conservation in coastal landscapes will be most likely to meet their objectives if they are designed from considerations that include: (1) an integrated perspective that river-estuary systems are influenced by effects of climate change operating on both watersheds and oceans; (2) varying sensitivity among environmental indicators to the uncertainty of future climates; (3) inevitability of biological community

  4. Sediment chronology in San Francisco Bay, California, defined by 210Pb, 234Th, 137Cs, and 239,340Pu

    Science.gov (United States)

    Fuller, C.C.; van Geen, Alexander; Baskaran, M.; Anima, R.

    1999-01-01

    Sediment chronologies based on radioisotope depth profiles were developed at two sites in the San Francisco Bay estuary to provide a framework for interpreting historical trends in organic compound and metal contaminant inputs. At Richardson Bay near the estuary mouth, sediments are highly mixed by biological and/or physical processes. Excess  penetration ranged from 2 to more than 10 cm at eight coring sites, yielding surface sediment mixing coefficients ranging from 12 to 170 cm2/year. At the site chosen for contaminant analyses, excess  activity was essentially constant over the upper 25 cm of the core with an exponential decrease below to the supported activity between 70 and 90 cm. Both  and  penetrated to 57-cm depth and have broad subsurface maxima between 33 and 41 cm. The best fit of the excess  profile to a steady state sediment accumulation and mixing model yielded an accumulation rate of 0.825 g/cm2/year (0.89 cm/year at sediment surface), surface mixing coefficient of 71 cm2/year, and 33-cm mixed zone with a half-Gaussian depth dependence parameter of 9 cm. Simulations of  and  profiles using these parameters successfully predicted the maximum depth of penetration and the depth of maximum  and  activity. Profiles of successive 1-year hypothetical contaminant pulses were generated using this parameter set to determine the age distribution of sediments at any depth horizon. Because of mixing, sediment particles with a wide range of deposition dates occur at each depth. A sediment chronology was derived from this age distribution to assign the minimum age of deposition and a date of maximum deposition to a depth horizon. The minimum age of sediments in a given horizon is used to estimate the date of first appearance of a contaminant from its maximum depth of penetration. The date of maximum deposition is used to estimate the peak year of input for a contaminant from the depth interval with the highest concentration of that contaminant

  5. Secular changes in the tidal constituents in San Francisco Bay originated by the California Gold Rush and major dam-building projects

    Science.gov (United States)

    Rodríguez, I.; Ortiz, M.

    2015-12-01

    Hourly sea-level records for the time period of 1901 to 2012 at Fort Point tidal station in San Francisco Bay are analyzed in an attempt to find the origin of the secular changes found in the tidal constituents. Complex demodulation implemented with a low pass filter window of 8760 hours was employed to extract the amplitude and phase of the principal tidal constituent M2 as a function of time. The 18.6 year nodal signal was removed by using the tide potential of the equilibrium tide. The results show significant trends up to 4 cm in amplitude as well as phase shifts of 17 minutes per century. Moreover, yearly amplitude variations of M2 show to be inversely correlated to river flow discharge. On the other hand, the results of a simplified two-layer numerical hydrodynamic model indicate that long-term tide variations are directly related to the morphological evolution of a sandbank located outside the bay surrounding its entrance, acting as a hydraulic control for the whole bay. According to historical results, the sandbank reached its shallowest depth during the California Gold Rush (1848-1884), when mining debris together with large amounts of sediment were deposited into the estuary. After the Central Valley Water Project was approved (1933), many dams were built decreasing significantly the sediment supply. With the passage of time, the gradual loss of sedimentation also diminished the sandbank, increasing its depth. This fact explains the observed secular long-term advance of the tidal phase, as well as the increasing trend of the M2 amplitude.

  6. One-Dimensional Convolutional Neural Network Land-Cover Classification of Multi-Seasonal Hyperspectral Imagery in the San Francisco Bay Area, California

    Directory of Open Access Journals (Sweden)

    Daniel Guidici

    2017-06-01

    Full Text Available In this study, a 1-D Convolutional Neural Network (CNN architecture was developed, trained and utilized to classify single (summer and three seasons (spring, summer, fall of hyperspectral imagery over the San Francisco Bay Area, California for the year 2015. For comparison, the Random Forests (RF and Support Vector Machine (SVM classifiers were trained and tested with the same data. In order to support space-based hyperspectral applications, all analyses were performed with simulated Hyperspectral Infrared Imager (HyspIRI imagery. Three-season data improved classifier overall accuracy by 2.0% (SVM, 1.9% (CNN to 3.5% (RF over single-season data. The three-season CNN provided an overall classification accuracy of 89.9%, which was comparable to overall accuracy of 89.5% for SVM. Both three-season CNN and SVM outperformed RF by over 7% overall accuracy. Analysis and visualization of the inner products for the CNN provided insight to distinctive features within the spectral-temporal domain. A method for CNN kernel tuning was presented to assess the importance of learned features. We concluded that CNN is a promising candidate for hyperspectral remote sensing applications because of the high classification accuracy and interpretability of its inner products.

  7. Handbook of Techniques and Guides for the Study of the San Francisco Bay-Delta-Estuary Complex, Part 4. Key to the Coastal Marine Fishes of California.

    Science.gov (United States)

    Alameda County School Dept., Hayward, CA.

    Project MER (Marine Ecology Research) is aimed at improving environmental education in the San Francisco Bay Area schools. As part of meeting this goal, it is hoped that students and teachers can see the results of their efforts being put to practical use. This guide is the fourth of a series which was produced to help students and teachers gather…

  8. Agricultural Chemical Concentrations and Loads in Rivers Draining the Central Valley, California, to the San Francisco Bay-Delta Estuary: Before and During an Extended Drought

    Science.gov (United States)

    Domagalski, J. L.

    2016-12-01

    Drought or near drought conditions have occurred in California since 2012. Although some parts of the State received near normal precipitation in water year 2016, other locations were still below average. Extended drought can impact aquatic organisms in a variety of ways because of decreased flows and elevated water temperature. However, lower precipitation and availability of irrigation water may limit subsequent runoff, resulting in reduced concentrations and loads of certain environmental toxicants, such as pesticides and ammonia, thereby limiting their toxic effects. In this study, funded by the U.S. Geological Survey National Water Quality Program, the occurrence of 227 pesticides and degradation products, and nutrients was assessed before and during this current drought in the two largest rivers draining to the San Francisco Bay: the Sacramento and San Joaquin Rivers. The watersheds of both rivers include substantial agricultural and urban land use. Herbicides, insecticides, fungicides, and ammonia were detected throughout the study (2010 to 2016) and models of daily concentration using the seasonal wave model (rloadest) were formulated to assess the amount of time that concentrations may have exceeded benchmark levels known to be toxic to aquatic organisms. Frequently detected pesticides included the fungicide azoxystrobin, herbicides or their degradation products such as diuron, glyphosate, and metolachlor, and insecticides such as imidacloprid. Compounds that are transported primarily by surface runoff generally showed decreasing concentrations as the drought progressed, especially in the San Joaquin River. Compounds mainly transported by groundwater, as indicated by seasonal concentration profiles, had more stable concentrations in the rivers. Mass loads to the Bay all decreased, as expected, because of the lower river discharge. When compared to aquatic-life benchmarks, modeled concentrations indicated that individual compounds were not contributing to

  9. Summary of California Clapper Rail winter populations in the San Francisco National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The California Clapper rail (Rallus lonqirostris obsoletus) is a seldom seen resident in some of the remaining tidal salt marshes in San Francisco Bay. The...

  10. Deep Borehole Instrumentation Along San Francisco Bay Bridges - 2000

    Energy Technology Data Exchange (ETDEWEB)

    Hutchings, L.; Kasameyer, P.; Turpin, C.; Long, L.; Hollfelder, J.; McEvilly, T.; Clymer, R.; Uhrhammer, R.

    2000-03-01

    This is a progress report on the Bay Bridges downhole network. Between 2 and 8 instruments have been spaced along the Dumbarton, San Mateo, Bay, and San Rafael bridges in San Francisco Bay, California. The instruments will provide multiple use data that is important to geotechnical, structural engineering, and seismological studies. The holes are between 100 and 1000 ft deep and were drilled by Caltrans. There are twenty-one sensor packages at fifteen sites. The downhole instrument package contains a three component HS-1 seismometer and three orthogonal Wilcox 731 accelerometers, and is capable of recording a micro g from local M = 1.0 earthquakes to 0.5 g strong ground motion form large Bay Area earthquakes. Preliminary results on phasing across the Bay Bridge, up and down hole wave amplification at Yerba Buena Island, and sensor orientation analysis are presented. Events recorded and located during 1999 are presented. Also, a senior thesis on the deep structure of the San Francisco Bay beneath the Bay Bridge is presented as an addendum.

  11. Deep Borehole Instrumentation Along San Francisco Bay Bridges - 2001

    Energy Technology Data Exchange (ETDEWEB)

    Hutchings, L.; Kasameyer, P.; Long, L.; McEvilly, T.; Clymer, R.; Urhhammer, R.; Baise, L.

    2001-05-01

    This is a progress report on the Bay Bridges downhole network. Between 2 and 8 instruments have been spaced along the Dumbarton, San Mateo, Bay, and San Rafael bridges in San Francisco Bay, California. The instruments will provide multiple use data that is important to geotechnical, structural engineering, and seismological studies. The holes are between 100 and 1000 ft deep and were drilled by Caltrans. There are twenty-one sensor packages at fifteen sites. The downhole instrument package contains a three component HS-1 seismometer and three orthogonal Wilcox 731 accelerometers, and is capable of recording a micro g from local M = 1.0 earthquakes to 0.5 g strong ground motion form large Bay Area earthquakes. This report list earthquakes and stations where recordings were obtained during the period February 29, 2000 to November 11, 2000. Also, preliminary results on noise analysis for up and down hole recordings at Yerba Buena Island is presented.

  12. A Water Quality Study: Heron's Head Park, San Francisco, California

    Science.gov (United States)

    Li, A.; Wu, K.; Neiss, J.

    2007-12-01

    Heron's Head Park, formerly known as Pier 98, is a 24-acre restored wetland, owned and operated by the Port of San Francisco and situated at the base of the Hunter's Point Power Plant. Heron's Head is a unique environment that is built on landfill and is now a thriving marsh maintained primarily by youth and community volunteers. Adjacent to the park stands a PG&E power plant (closed May 2006), a county waste transfer station, and a combined sewer overflow (CSO) pipe. The park is bordered by San Francisco Bay on the north, east and south sides of the park. We examined the levels of ammonia, nitrite, nitrate, phosphate and fecal coliform at nine sites around the park. Utilizing historical data from other San Francisco Bay sites and other similar estuarine settings in California, we assessed the health of the Bay waters surrounding the park. We found the levels of ammonia, nitrate, nitrite and phosphates to be within the parameters of historical San Francisco Bay data and similar to settings such as Elkhorn Slough, Tomales Bay and Tijuana Estuary. In our study we did find a potential hazard to human health. Fecal coliform concentrations in waters that border the park range from 340 MPN/100 mL - 24,000 MPN/100 mL. This level significantly exceeds Environmental Protection Agency recommendations of 300 MPN/100 mL for human contact with water.

  13. A century of landscape disturbance and urbanization of the San Francisco Bay region affects the present-day genetic diversity of the California Ridgway’s Rail (Rallus obsoletus obsoletus)

    Science.gov (United States)

    Wood, Dustin A.; Bui, Thuy-Vy D.; Overton, Cory T.; Vandergast, Amy; Casazza, Michael L.; Hull, Joshua M.; Takekawa, John Y.

    2016-01-01

    Fragmentation and loss of natural habitat have important consequences for wild populations and can negatively affect long-term viability and resilience to environmental change. Salt marsh obligate species, such as those that occupy the San Francisco Bay Estuary in western North America, occupy already impaired habitats as result of human development and modifications and are highly susceptible to increased habitat loss and fragmentation due to global climate change. We examined the genetic variation of the California Ridgway’s rail ( Rallus obsoletus obsoletus), a state and federally endangered species that occurs within the fragmented salt marsh of the San Francisco Bay Estuary. We genotyped 107 rails across 11 microsatellite loci and a single mitochondrial gene to estimate genetic diversity and population structure among seven salt marsh fragments and assessed demographic connectivity by inferring patterns of gene flow and migration rates. We found pronounced genetic structuring among four geographically separate genetic clusters across the San Francisco Bay. Gene flow analyses supported a stepping stone model of gene flow from south-to-north. However, contemporary gene flow among the regional embayments was low. Genetic diversity among occupied salt marshes and genetic clusters were not significantly different. However, we detected low effective population sizes and significantly high relatedness among individuals within salt marshes. Preserving genetic diversity and connectivity throughout the San Francisco Bay may require attention to salt marsh restoration in the Central Bay where habitat is both most limited and most fragmented. Incorporating periodic genetic sampling in to the management regime may help evaluate population trends and guide long-term management priorities.These data support the following in-press publication: Wood, D.A., Bui, T.D., Overton, C.T., Vandergast, A.G., Casazza, M.L., Hull, J.M., and Takekawa, J.Y. Conservation Genetics (2016

  14. Bathymetry--Offshore of San Francisco, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetry and shaded-relief maps of Offshore of San Francisco, California (raster data file is included in...

  15. Habitat--Offshore of San Francisco, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the habitat map of the seafloor of the Offshore of San Francisco map area, California. The vector data file is included in...

  16. Habitat--Offshore of San Francisco, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the habitat map of the seafloor of the Offshore of San Francisco map area, California. The vector data file is included in...

  17. Contours--Offshore of San Francisco, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore of San Francisco map area, California. The vector data file...

  18. Status and understanding of groundwater quality in the North San Francisco Bay Shallow Aquifer study unit, 2012; California GAMA Priority Basin Project

    Science.gov (United States)

    Bennett, George L.

    2017-07-20

    Groundwater quality in the North San Francisco Bay Shallow Aquifer study unit (NSF-SA) was investigated as part of the Priority Basin Project of the California Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study unit is in Marin, Mendocino, Napa, Solano, and Sonoma Counties and included two physiographic study areas: the Valleys and Plains area and the surrounding Highlands area. The NSF-SA focused on groundwater resources used for domestic drinking water supply, which generally correspond to shallower parts of aquifer systems than that of groundwater resources used for public drinking water supply in the same area. The assessments characterized the quality of untreated groundwater, not the quality of drinking water.This study included three components: (1) a status assessment, which characterized the status of the quality of the groundwater resources used for domestic supply for 2012; (2) an understanding assessment, which evaluated the natural and human factors potentially affecting water quality in those resources; and (3) a comparison between the groundwater resources used for domestic supply and those used for public supply.The status assessment was based on data collected from 71 sites sampled by the U.S. Geological Survey for the GAMA Priority Basin Project in 2012. To provide context, concentrations of constituents measured in groundwater were compared to U.S. Environmental Protection Agency (EPA) and California State Water Resources Control Board Division of Drinking Water regulatory and non-regulatory benchmarks for drinking-water quality. The status assessment used a grid-based method to estimate the proportion of the groundwater resources that has concentrations of water-quality constituents approaching or above benchmark concentrations. This method provides statistically unbiased results at the study-area scale and permits comparisons to other GAMA Priority Basin Project study areas.In the NSF-SA study unit as a whole, inorganic

  19. San Francisco Bay Long Term Management Strategy for Dredging

    Science.gov (United States)

    The San Francisco Bay Long Term Management Strategy (LTMS) is a cooperative effort to develop a new approach to dredging and dredged material disposal in the San Francisco Bay area. The LTMS serves as the Regional Dredging Team for the San Francisco area.

  20. Mercury concentrations in blood and feathers of prebreeding Forster's terns in relation to space use of San Francisco Bay, California, USA, habitats.

    Science.gov (United States)

    Ackerman, Joshua T; Eagles-Smith, Collin A; Takekawa, John Y; Bluso, Jill D; Adelsbach, Terrence L

    2008-04-01

    We examined mercury concentrations and space use of prebreeding Forster's terns (Sterna forsteri) in San Francisco Bay, California, USA, to assess factors influencing mercury levels in piscivorous birds. In 2005 and 2006, we collected blood and feathers from 122 Forster's terns and radio-marked and tracked 72 terns to determine locations of dietary mercury uptake. Capture site and capture date were the most important factors explaining variation in blood mercury concentrations (geometric mean +/- standard error: 1.09+/-0.89 microg/g wet wt), followed by sex and year. Accordingly, radiotelemetry data revealed that Forster's terns generally remained near their site of capture and foraged in nearby salt ponds, managed and tidal marshes, and tidal flats. In contrast, capture site and capture date were not important factors explaining variation in feather mercury concentrations, probably because feathers were grown on their wintering grounds several months prior to our sampling. Instead, sex and year were the most important factors explaining mercury concentrations in breast feathers (9.57+/-8.23 microg/g fresh wt), and sex was the most important factor for head feathers (6.94+/-7.04 microg/g fresh wt). Overall, 13 and 22% of prebreeding Forster's terns were estimated to be at high risk for deleterious effects due to mercury concentrations in blood (>3.0 microg/g wet wt) and feathers (>20.0 microg/g fresh wt), respectively. Breeding terns are likely to be even more at risk because blood mercury concentrations more than tripled during the 45-d prebreeding time period. These data illustrate the importance of space use and tissue type in interpreting mercury concentrations in birds.

  1. Food Quality and Phytoplankton Community Composition in San Francisco Bay using Imaging Spectroscopy Data from the California HyspIRI Airborne Campaign

    Science.gov (United States)

    Palacios, S. L.; Peacock, M. B.; Golini, A. N.; Cloern, J. E.; Senn, D. B.; Guild, L. S.; Kudela, R. M.

    2016-12-01

    The San Francisco Bay (SFB) is the largest estuary on the west coast of the United States. It is an important transition zone between marine, freshwater, and inland terrestrial watersheds. The SFB is an important region for the cycling of nutrients and pollutants and it supports nurseries of ecologically and commercially important fisheries, including some threatened species. Phytoplankton community structure influences food web dynamics, and the taxonomy of the phytoplankton may be more important in determining primary "food quality" than environmental factors. As such, estimating food quality from phytoplankton community composition can be a robust tool to understand trophic transfer of energy. Recent work explores phytoplankton "food quality" in SFB through the use of microscopy and phytoplankton chemotaxonomy to evaluate how changes in phytoplankton composition may have influenced the recent trophic collapse of pelagic fishes in the northern part of the SFB. The objective of this study is to determine if the approach can also be applied to imaging spectroscopy data in order to quantify phytoplankton "food quality" from space. Imaging spectroscopy data of SFB from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) was collected during the Hyperspectral Infrared (HyspIRI) Airborne Campaign in California (2013 - 2015) and used in this study. Estimates of ocean chlorophyll and phytoplankton community structure were determined using standard ocean chlorophyll algorithms and the PHYtoplankton Detection with Optics (PHYDOTax) algorithms. These were validated using in situ observations of phytoplankton composition using microscopic cell counts and phytoplankton chemotaxonomy from the US Geological Survey's ship surveys of the SFB. The findings from this study may inform the use of future high spectral resolution satellite sensors with the spatial resolution appropriate for coastal systems (e.g., HyspIRI) to assess "food quality" from space.

  2. Changes in production and respiration during a spring phytoplankton bloom in San Francisco Bay, California, USA: Implications for net ecosystem metabolism

    Science.gov (United States)

    Caffrey, J.M.; Cloern, J.E.; Grenz, C.

    1998-01-01

    We present results of an intensive sampling program designed to measure weekly changes in ecosystem respiration (oxygen consumption in the water column and sediments) around the 1996 spring bloom in South San Francisco Bay, California, USA. Measurements were made at a shallow site (2 m, where mean photic depth was 60% of the water column height) and a deep site (15 m, mean photic depth was only 20% of the water column). We also estimated phytoplankton primary production weekly at both sites to develop estimates of net oxygen flux as the sum of pelagic production (PP), pelagic respiration (PR) and benthic respiration (BR). Over the 14 wk period from February 5 to May 14, PP ranged from 2 to 210, PR from 9 to 289, and BR from 0.1 to 48 mmol O2 m-2 d-1, illustrating large variability of estuarine oxygen fluxes at the weekly time scale. Pelagic production exceeded total respiration at the shallow site, but not at the deep site, demonstrating that the shallow domains are net autotrophic but the deep domains are net heterotrophic, even during the period of the spring bloom. If we take into account the potential primary production by benthic microalgae, the estuary as a whole is net autotrophic during spring, net heterotrophic during the nonbloom seasons, and has a balanced net metabolism over a full annual period. The seasonal shift from net autotrophy to heterotrophy during the transition from spring to summer was accompanied by a large shift from dominance by pelagic respiration to dominance by benthic respiration. This suggests that changes in net ecosystem metabolism can reflect changes in the pathways of energy flow in shallow coastal ecosystems.

  3. The San Andreas Fault in the San Francisco Bay area, California: a geology fieldtrip guidebook to selected stops on public lands

    Science.gov (United States)

    Stoffer, Philip W.

    2005-01-01

    This guidebook contains a series of geology fieldtrips with selected destinations along the San Andreas Fault in part of the region that experienced surface rupture during the Great San Francisco Earthquake of 1906. Introductory materials present general information about the San Andreas Fault System, landscape features, and ecological factors associated with faults in the South Bay, Santa Cruz Mountains, the San Francisco Peninsula, and the Point Reyes National Seashore regions. Trip stops include roadside areas and recommended hikes along regional faults and to nearby geologic and landscape features that provide opportunities to make casual observations about the geologic history and landscape evolution. Destinations include the sites along the San Andreas and Calaveras faults in the San Juan Bautista and Hollister region. Stops on public land along the San Andreas Fault in the Santa Cruz Mountains in Santa Clara and Santa Cruz counties include in the Loma Prieta summit area, Forest of Nicene Marks State Park, Lexington County Park, Sanborn County Park, Castle Rock State Park, and the Mid Peninsula Open Space Preserve. Destinations on the San Francisco Peninsula and along the coast in San Mateo County include the Crystal Springs Reservoir area, Mussel Rock Park, and parts of Golden Gate National Recreation Area, with additional stops associated with the San Gregorio Fault system at Montara State Beach, the James F. Fitzgerald Preserve, and at Half Moon Bay. Field trip destinations in the Point Reyes National Seashore and vicinity provide information about geology and character of the San Andreas Fault system north of San Francisco.

  4. Polychlorinated biphenyls (PCBs) and their hydroxylated metabolites (OH-PCBs) in harbor seal () livers from San Francisco Bay, California and Gulf of Maine

    OpenAIRE

    Park, June-Soo; Kalantzi, Olga Ioanna; Kopec, Dianne; Petreas, Myrto

    2009-01-01

    Abstract Bioaccumulation of endocrine disruptors in marine mammals positioned at the top of the food chain is of toxicological concern. Stranded four pup and ten adult harbor seal (Phoca vitulina) livers were collected from San Francisco Bay and the Gulf of Maine and analyzed for polychlorinated biphenyls (PCBs) and their hydroxylated metabolites (OH-PCBs). We used GC-ECD and GC-NCI/MS to investigate the presence of 28 PCBs and 8 OH-PCB metabolites, respectively. ?28PCB concentrati...

  5. Continuous water-quality and suspended-sediment transport monitoring in the San Francisco Bay, California, water years 2011-13

    Science.gov (United States)

    Buchanan, Paul A.; Downing-Kunz, Maureen A.; Schoellhamer, David H.; Shellenbarger, Gregory; Weidich, Kurt W.

    2014-01-01

    The U.S. Geological Survey (USGS) monitors water quality and suspended-sediment transport in the San Francisco Bay. The San Francisco Bay area is home to millions of people, and the bay teems with both resident and migratory wildlife, plants, and fish. Fresh water mixes with salt water in the bay, which is subject both to riverine and marine (tides, waves, influx of salt water) influences. To understand this environment, the USGS, along with its partners, has been monitoring the bay’s waters continuously since 1988. Several water-quality variables are of particular importance to State and Federal resource managers and are monitored at key locations throughout the bay. Salinity, which indicates the relative mixing of fresh and ocean waters in the bay, is derived from specific conductance measurements. Water temperature, along with salinity, affects the density of water, which causes gravity driven circulation patterns and stratification in the water column. Turbidity is measured using light-scattering from suspended solids in water, and is used as a surrogate for suspended-sediment concentration (SSC). Suspended sediment often carries adsorbed contaminants; attenuates sunlight in the water column; deposits on tidal marsh and intertidal mudflats, which can help sustain these habitats as sea level rises; and deposits in ports and shipping channels, which can necessitate dredging. Dissolved oxygen, which is essential to a healthy ecosystem, is a fundamental indicator of water quality, and its concentration is affected by water temperature, salinity, ecosystem metabolism, tidal currents, and wind. Tidal currents in the bay reverse four times a day, and wind direction and intensity typically change on a daily cycle: consequently, salinity, water temperature, suspendedsediment concentration, and dissolvedoxygen concentration vary spatially and temporally throughout the bay, and continuous measurements are needed to observe these changes. The purpose of this fact sheet

  6. Near-field receiving water monitoring of trace metals and a benthic community near the Palo Alto Regional Water Quality Control Plant in south San Francisco Bay, California; 2015

    Science.gov (United States)

    Cain, Daniel J.; Thompson, Janet K.; Crauder, Jeffrey; Parchaso, Francis; Stewart, Robin; Turner, Matthew A.; Hornberger, Michelle I.; Luoma, Samuel N.

    2016-07-22

    Trace-metal concentrations in sediment and in the clam Macoma petalum (formerly reported as Macoma balthica), clam reproductive activity, and benthic macroinvertebrate community structure were investigated in a mudflat 1 kilometer south of the discharge of the Palo Alto Regional Water Quality Control Plant (PARWQCP) in South San Francisco Bay, California. This report includes data collected by U.S. Geological Survey (USGS) scientists for the period from January 2015 to December 2015. These data are appended to long-term datasets extending back to 1974, and serve as the basis for the City of Palo Alto’s Near-Field Receiving Water Monitoring Program, initiated in 1994.

  7. An overview of San Francisco Bay PORTS

    Science.gov (United States)

    Cheng, Ralph T.; McKinnie, David; English, Chad; Smith, Richard E.

    1998-01-01

    The Physical Oceanographic Real-Time System (PORTS) provides observations of tides, tidal currents, and meteorological conditions in real-time. The San Francisco Bay PORTS (SFPORTS) is a decision support system to facilitate safe and efficient maritime commerce. In addition to real-time observations, SFPORTS includes a nowcast numerical model forming a San Francisco Bay marine nowcast system. SFPORTS data and nowcast numerical model results are made available to users through the World Wide Web (WWW). A brief overview of SFPORTS is presented, from the data flow originated at instrument sensors to final results delivered to end users on the WWW. A user-friendly interface for SFPORTS has been designed and implemented. Appropriate field data analysis, nowcast procedures, design and generation of graphics for WWW display of field data and nowcast results are presented and discussed. Furthermore, SFPORTS is designed to support hazardous materials spill prevention and response, and to serve as resources to scientists studying the health of San Francisco Bay ecosystem. The success (or failure) of the SFPORTS to serve the intended user community is determined by the effectiveness of the user interface.

  8. Mercury-contaminated hydraulic mining debris in San Francisco Bay

    Science.gov (United States)

    Bouse, Robin M.; Fuller, Christopher C.; Luoma, Samuel N.; Hornberger, Michelle I.; Jaffe, Bruce E.; Smith, Richard E.

    2010-01-01

    The hydraulic gold-mining process used during the California Gold Rush and in many developing countries today contributes enormous amounts of sediment to rivers and streams. Commonly, accompanying this sediment are contaminants such as elemental mercury and cyanide used in the gold extraction process. We show that some of the mercurycontaminated sediment created by hydraulic gold mining in the Sierra Nevada, between 1852 and 1884, ended up over 250 kilometers (km) away in San Francisco Bay; an example of the far-reaching extent of contamination from such activities.

  9. Bair Island Restoration and Management Plan : Don Edwards San Francisco Bay National Wildlife Refuge : Bair Island Ecological Reserve

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The U.S. Fish and Wildlife Service, Don Edwards San Francisco Bay National Wildlife Refuge, and the California Department of Fish and Game are proposing adoption of...

  10. Contaminant levels in fish tissue from San Francisco Bay

    Energy Technology Data Exchange (ETDEWEB)

    Fairey, R. [California Dept. of Fish and Game, Moss Landing, CA (United States). Moss Landing Marine Labs.; Taberski, K. [San Francisco Bay Regional Water Quality Control Board, Oakland, CA (United States)

    1995-12-31

    Edible fish species were collected from thirteen locations throughout San Francisco Bay, during the spring of 1994, for determination of contaminants levels in muscle tissue. Species collected included white croaker, surfperch, leopard and brown smoothhound sharks, striped bass, white sturgeon and halibut Sixty six composite tissue samples were analyzed for the presence of PAHs, PCBs, pesticides, trace elements and dioxin/furans. The US EPA approach to assessing chemical contaminant data for fish tissue consumption was used for identifying the primary chemicals of concern. Six chemicals or chemical groups were found to exceed screening levels established using the US EPA approach. PCBs (as total Aroclors) exceeded the screening level of 3 ppb in all sixty six tissue samples, with the highest concentrations (638 ppb) found near San Francisco`s industrial areas. Mercury was elevated (> 0.14 ppm) in forty of the sixty-six samples with the highest levels (1.26 ppm) occurring in shark muscle tissues. Concentrations of the organochlorine pesticides dieldrin, total chlordanes and total DDTs exceeded screening levels in a number of samples. Dioxin/furans (as TEQs) were elevated (above 0.15 ppt) in 16 of the 19 samples analyzed. Fish with high lipid content (croaker and surfperch) in their muscle tissue generally exhibited higher contaminant levels while fish with low lipid levels (halibut and shark) exhibited lower organic contaminant levels. Tissue samples taken from North Bay stations most often exhibited high levels of chemical contamination. The California Office of Health Hazard Assessment is currently evaluating the results of this study and has issued an interim Health Advisory concerning the human consumption of fish tissue from San Francisco Bay.

  11. Microbial biogeography of San Francisco Bay sediments

    Science.gov (United States)

    Lee, J. A.; Francis, C. A.

    2014-12-01

    The largest estuary on the west coast of North America, San Francisco Bay is an ecosystem of enormous biodiversity, and also enormous human impact. The benthos has experienced dredging, occupation by invasive species, and over a century of sediment input as a result of hydraulic mining. Although the Bay's great cultural and ecological importance has inspired numerous surveys of the benthic macrofauna, to date there has been almost no investigation of the microbial communities on the Bay floor. An understanding of those microbial communities would contribute significantly to our understanding of both the biogeochemical processes (which are driven by the microbiota) and the physical processes (which contribute to microbial distributions) in the Bay. Here, we present the first broad survey of bacterial and archaeal taxa in the sediments of the San Francisco Bay. We conducted 16S rRNA community sequencing of bacteria and archaea in sediment samples taken bimonthly for one year, from five sites spanning the salinity gradient between Suisun and Central Bay, in order to capture the effect of both spatial and temporal environmental variation on microbial diversity. From the same samples we also conducted deep sequencing of a nitrogen-cycling functional gene, nirS, allowing an assessment of evolutionary diversity at a much finer taxonomic scale within an important and widespread functional group of bacteria. We paired these sequencing projects with extensive geochemical metadata as well as information about macrofaunal distribution. Our data reveal a diversity of distinct biogeographical patterns among different taxa: clades ubiquitous across sites; clades that respond to measurable environmental drivers; and clades that show geographical site-specificity. These community datasets allow us to test the hypothesis that salinity is a major driver of both overall microbial community structure and community structure of the denitrifying bacteria specifically; and to assess

  12. 77 FR 57494 - Safety Zone; Fleet Week Fireworks, San Francisco Bay, San Francisco, CA

    Science.gov (United States)

    2012-09-18

    ... SECURITY Coast Guard 33 CFR Part 165 Safety Zone; Fleet Week Fireworks, San Francisco Bay, San Francisco... will enforce the safety zone for the Fleet Week Fireworks in the Captain of the Port, San Francisco...'' W (NAD83) for the Fleet Week Fireworks in 33 CFR 165.1191, Table 1, item number 25. This safety...

  13. Arias intensity assessment of liquefaction test sites on the east side of San Francisco Bay affected by the Loma Prieta, California, earthquake of 17 October 1989

    Science.gov (United States)

    Kayen, R.E.

    1997-01-01

    Abstract. Uncompacted artificial-fill deposits on the east side of San Francisco Bay suffered severe levels of soil liquefaction during the Loma Prieta earthquake of 17 October 1989. Damaged areas included maritime-port facilities, office buildings, and shoreline transportation arteries, ranging from 65 to 85 km from the north end of the Loma Prieta rupture zone. Typical of all these sites, which represent occurrences of liquefaction-induced damage farthest from the rupture zone, are low cone penetration test and Standard Penetration Test resistances in zones of cohesionless silty and sandy hydraulic fill, and underlying soft cohesive Holocene and Pleistocene sediment that strongly amplified ground motions. Postearthquake investigations at five study sites using standard penetration tests and cone penetration tests provide a basis for evaluation of the Arias intensity-based methodology for assessment of liquefaction susceptibility. ?? 1997 Kluwer Academic Publishers.

  14. Subsurface structure and kinematics of the Calaveras-Hayward fault stepover from three-dimensional Vp and seismicity, San Francisco Bay region, California

    Science.gov (United States)

    Manaker, David M.; Michael, Andrew J.; Burgmann, Roland

    2005-01-01

    The Calaveras and Hayward faults are major components of the San Andreas fault system in the San Francisco Bay region. Dextral slip is presumed to transfer from the Calaveras fault to the Hayward fault in the Mission Hills region, an area of uplift in the contractional stepover between the two faults. Here the estimated deep slip rates drop from 15 to 6 mm/yr on the Calaveras fault, and slip begins on the Hayward fault at an estimated 9 mm/yr. A lineament of microseismicity near the Mission fault links the seismicity on the Calaveras and Hayward faults and is presumed to be related directly to this slip transfer. However, geologic and seismologic evidence suggest that the Mission fault may not be the source of the seismicity and that the Mission fault is not playing a major role in the slip transfer.

  15. Giant sand waves at the mouth of San Francisco Bay

    Science.gov (United States)

    Barnard, P.L.; Hanes, D.M.; Rubin, D.M.; Kvitek, R.G.

    2006-01-01

    A field of giant sand waves, among the largest in the world, recently was mapped in high resolution for the first time during a multibeam survey in 2004 and 2005 through the strait of the Golden Gate at the mouth of San Francisco Bay in California (Figure la). This massive bed form field covers an area of approximately four square kilometers in water depths ranging from 30 to 106 meters, featuring more than 40 distinct sand waves with crests aligned approximately perpendicular to the dominant tidally generated cross-shore currents, with wavelengths and heights that measure up to 220 meters and 10 meters, respectively. Sand wave crests can be traced continuously for up to two kilometers across the mouth of this energetic tidal inlet, where depth-averaged tidal currents through the strait below the Golden Gate Bridge exceed 2.5 meters per second during peak ebb flows. Repeated surveys demonstrated that the sand waves are active and dynamic features that move in response to tidally generated currents. The complex temporal and spatial variations in wave and tidal current interactions in this region result in an astoundingly diverse array of bed form morphologies, scales, and orientations. Bed forms of approximately half the scale of those reported in this article previously were mapped inside San Francisco Bay during a multibeam survey in 1997 [Chin et al., 1997].

  16. Applying Integrated ITS Technologies to Parking Management Systems: A Transit-Based Case Study in the San Francisco Bay Area

    OpenAIRE

    Shaheen, Susan; Rodier, Caroline J.; Eaken, Amanda M.

    2004-01-01

    California Partners for Advanced Transit and Highways has teamed with the California Department of Transportation, the Bay Area Rapid Transit (BART) District, ParkingCarmaâ„¢, and Quixote Corporation to launch a smart parking research demonstration at the Rockridge BART station in the East San Francisco Bay Area (California, USA). The results of an extensive literature review demonstrate that different smart parking applications implemented worldwide can ease traveler delays, increase transit...

  17. Don Edwards San Francisco Bay National Wildlife Refuge : Self Monitoring Program for Alviso Ponds Within South San Francisco Bay Low Salinity Salt Ponds Alameda, Santa Clara, and San Mateo Counties, California : 2004

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual report summarizes the results of the 2004 water quality sampling conducted at the Alviso Ponds in Santa Clara County, California, which are part of the...

  18. Don Edwards San Francisco Bay National Wildlife Refuge : Self Monitoring Program for Alviso Ponds Within South San Francisco Bay Low Salinity Salt Ponds Alameda, Santa Clara, and San Mateo Counties, California : 2005

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual report summarizes the results of the 2005 water quality sampling conducted at the Alviso Ponds in Santa Clara County, California, which are part of the...

  19. Don Edwards San Francisco Bay National Wildlife Refuge : Self Monitoring Program for Alviso Ponds Within South San Francisco Bay Low Salinity Salt Ponds Alameda, Santa Clara, and San Mateo Counties, California : 2006

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual report summarizes the results of the 2006 water quality sampling conducted at the Alviso Ponds in Santa Clara County, California, which are part of the...

  20. Don Edwards San Francisco Bay National Wildlife Refuge : Self Monitoring Program for Alviso Ponds Within South San Francisco Bay Low Salinity Salt Ponds Alameda, Santa Clara, and San Mateo Counties, California : 2010

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual report summarizes the results of the 2010 water quality sampling conducted at the Alviso Ponds in Santa Clara County, California, which are part of the...

  1. Don Edwards San Francisco Bay National Wildlife Refuge : Self Monitoring Program for Alviso Ponds Within South San Francisco Bay Low Salinity Salt Ponds Alameda, Santa Clara, and San Mateo Counties, California : 2007

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual report summarizes the results of the 2007 water quality sampling conducted at the Alviso Ponds in Santa Clara County, California, which are part of the...

  2. Don Edwards San Francisco Bay National Wildlife Refuge : Self Monitoring Program for Alviso Ponds Within South San Francisco Bay Low Salinity Salt Ponds Alameda, Santa Clara, and San Mateo Counties, California : 2008

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual report summarizes the results of the 2008 water quality sampling conducted at the Alviso Ponds in Santa Clara County, California, which are part of the...

  3. Don Edwards San Francisco Bay National Wildlife Refuge : Self Monitoring Program for Alviso Ponds Within South San Francisco Bay Low Salinity Salt Ponds Alameda, Santa Clara, and San Mateo Counties, California : 2009

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual report summarizes the results of the 2009 water quality sampling conducted at the Alviso Ponds in Santa Clara County, California, which are part of the...

  4. Predicted liquefaction of East Bay fills during a repeat of the 1906 San Francisco earthquake

    Science.gov (United States)

    Holzer, T.L.; Blair, J.L.; Noce, T.E.; Bennett, M.J.

    2006-01-01

    Predicted conditional probabilities of surface manifestations of liquefaction during a repeat of the 1906 San Francisco (M7.8) earthquake range from 0.54 to 0.79 in the area underlain by the sandy artificial fills along the eastern shore of San Francisco Bay near Oakland, California. Despite widespread liquefaction in 1906 of sandy fills in San Francisco, most of the East Bay fills were emplaced after 1906 without soil improvement to increase their liquefaction resistance. They have yet to be shaken strongly. Probabilities are based on the liquefaction potential index computed from 82 CPT soundings using median (50th percentile) estimates of PGA based on a ground-motion prediction equation. Shaking estimates consider both distance from the San Andreas Fault and local site conditions. The high probabilities indicate extensive and damaging liquefaction will occur in East Bay fills during the next M ??? 7.8 earthquake on the northern San Andreas Fault. ?? 2006, Earthquake Engineering Research Institute.

  5. San Francisco Bay National Wildlife Refuge Complex Annual Narrative Report 1979

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The San Francisco Bay National Wildlife Refuge Complex comprises of three refuges including the San Francisco Bay National Wildlife Refuge, the San Pablo Bay...

  6. San Francisco Bay National Wildlife Refuge Complex Annual Narrative Report 1983

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The San Francisco Bay National Wildlife Refuge Complex comprises of three refuges including the San Francisco Bay National Wildlife Refuge, the San Pablo Bay...

  7. San Francisco Bay National Wildlife Refuge Complex Annual Narrative Report 1981

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The San Francisco Bay National Wildlife Refuge Complex comprises of three refuges including the San Francisco Bay National Wildlife Refuge, the San Pablo Bay...

  8. San Francisco Bay National Wildlife Refuge Complex Annual Narrative Report 1977

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The San Francisco Bay National Wildlife Refuge Complex comprises of three refuges including the San Francisco Bay National Wildlife Refuge, the San Pablo Bay...

  9. Marine Seismic Reflection Profiles Data of San Francisco Bay Area

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Dataset consists of two-dimensional marine seismic reflection profile data from the San Francisco Bay area. These data were acquired in 1995, with the vessel Robert...

  10. Narrative Report : San Francisco Bay NWR Complex : Fiscal Year 1974

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report details the conditions and management of San Francisco Bay National Wildlife Refuge in 1974. The report begins with a general...

  11. San Francisco Bay National Wildlife Refuge Complex : Annual Narrative 1980

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report details the conditions and management of San Francisco Bay National Wildlife Refuge in 1980. The report begins with a general...

  12. Salinity and Flow Monitoring in the San Francisco Bay Delta

    Science.gov (United States)

    This report describes the utility and approximate cost of expanding the salinity water quality monitoring network along the axis of the San Francisco Estuary from Suisun Bay to Rio Vista on the Sacramento River.

  13. National Status and Trends: Bioeffects Program - San Francisco Bay Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This study was based on the sediment quality triad (SQT) approach. A stratified probabilistic sampling design was utilized to characterize the San Francisco Bay...

  14. San Francisco Bay Conservation and Development Commission : Annual Report 1972

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Congress passed, and the President signed into law, legislation establishing the San Francisco Bay National Wildlife Refuge. When the purchase of property for...

  15. Marine Seismic Reflection Profiles Data of San Francisco Bay Area

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Dataset consists of two-dimensional marine seismic reflection profile data from the San Francisco Bay area. These data were acquired in 1993, with the vessel David...

  16. Marine Seismic Reflection Profiles Data of San Francisco Bay Area

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Dataset consists of two-dimensional marine seismic reflection profile data from the San Francisco Bay area. These data were acquired in 1997, with the vessel Davidt...

  17. Hunting plan for San Francisco Bay National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This migratory waterfowl hunting plan for Don Edwards San Francisco Bay National Wildlife Refuge allows waterfowl hunting on certain areas of the Refuge. Aerial...

  18. Marine Seismic Reflection Profiles Data of San Francisco Bay Area

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Dataset consists of two-dimensional marine seismic reflection profile data from the San Francisco Bay area. These data were acquired in 1995, with the vessel Robert...

  19. Marine Seismic Reflection Profiles Data of San Francisco Bay Area

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Dataset consists of two-dimensional marine seismic reflection profile data from the San Francisco Bay area. These data were acquired in 1993, with the vessel David...

  20. Sea-Floor Images and Data from Multibeam Surveys in San Francisco Bay, Southern California, Hawaii, the Gulf of Mexico, and Lake Tahoe, California-Nevada

    Science.gov (United States)

    Dartnell, Peter; Gardiner, James V.

    1999-01-01

    Accurate base maps are a prerequisite for any geologic study, regardless of the objectives. Land-based studies commonly utilize aerial photographs, USGS 7.5-minute quadrangle maps, and satellite images as base maps. Until now, studies that involve the ocean floor have been at a disadvantage due to an almost complete lack of accurate marine base maps. Many base maps of the sea floor have been constructed over the past century but with a wide range in navigational and depth accuracies. Only in the past few years has marine surveying technology advanced far enough to produce navigational accuracy of 1 meter and depth resolutions of 50 centimeters. The Pacific Seafloor Mapping Project of the U.S. Geological Survey's, Western Coastal and Marine Geology Program, Menlo Park, California, U.S.A., in cooperation with the Ocean Mapping Group, University of New Brunswick, Fredericton, Canada, is using this new technology to systematically map the ocean floor and lakes. This type of marine surveying, called multibeam surveying, collects high-resolution bathymetric and backscatter data that can be used for various base maps, GIS coverages, and scientific visualization methods. This is an interactive CD-ROM that contains images, movies, and data of all the surveys the Pacific Seafloor Mapping Project has completed up to January 1999. The images and movies on this CD-ROM, such as shaded relief of the bathymetry, backscatter, oblique views, 3-D views, and QuickTime movies help the viewer to visualize the multibeam data. This CD-ROM also contains ARC/INFO export (.e00) files and full-resolution TIFF images of all the survey sites that can be downloaded and used in many GIS packages.

  1. 75 FR 8106 - Don Edwards San Francisco Bay National Wildlife Refuge, Alameda, Santa Clara, and San Mateo...

    Science.gov (United States)

    2010-02-23

    ... Fish and Wildlife Service Don Edwards San Francisco Bay National Wildlife Refuge, Alameda, Santa Clara... located in Alameda, Santa Clara, and San Mateo Counties of California. We provide this notice in... in Alameda, Santa Clara, and San Mateo Counties of California, consists of several non...

  2. Whole grains and risk of pancreatic cancer in a large population-based case-control study in the San Francisco Bay Area, California.

    Science.gov (United States)

    Chan, June M; Wang, Furong; Holly, Elizabeth A

    2007-11-15

    Epidemiologic data suggest that consumption of whole-grain products may be inversely associated with risk of pancreatic cancer. Grain intake was examined in a population-based case-control study of pancreatic cancer in the San Francisco Bay Area (1995-1999). A 131-item semiquantitative food frequency questionnaire was administered to 532 cases and 1,701 controls. Odds ratios and 95% confidence intervals were computed as estimates of relative risk. Persons who consumed > or =2 servings of whole grains daily had a lower risk of pancreatic cancer than persons who consumed tortillas (OR = 0.56, 95% CI: 0.35, 0.89; trend-p = 0.02). Consumption of doughnuts (> or =2 servings/week vs. or =2 servings/week vs. Dietary fiber was inversely associated with risk (for highest quartile vs. lowest, OR = 0.65, 95% CI: 0.47, 0.89; trend-p = 0.02). These data provide some support for the hypothesis that consuming more whole-grain or high-fiber foods may reduce the risk of pancreatic cancer. Refined grains were not associated with risk.

  3. Southern San Francisco Bay Colonial Nesting Bird Census 1995-1996: Don Edwards San Francisco Bay National Wildlife Refuge Lands

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes the 1995-1996 field season of the San Francisco Bay Bird Observatory (SFBBO) Colonial Waterbird Monitoring Study on the Don Edwards San...

  4. San Francisco Bay Area Baseline Trash Loading Summary Results, San Francisco Bay Area CA, 2012, US EPA Region 9

    Data.gov (United States)

    U.S. Environmental Protection Agency — The San Francisco Bay Area stormwater permit sets trash control guidelines for discharges through the storm drain system. The permit covers Alameda, Contra Costa,...

  5. Large-scale right-slip displacement on the East San Francisco Bay Region fault system, California: Implications for location of late Miocene to Pliocene Pacific plate boundary

    Science.gov (United States)

    McLaughlin, R.J.; Sliter, W.V.; Sorg, D.H.; Russell, P.C.; Sarna-Wojcicki, A. M.

    1996-01-01

    A belt of northwardly younging Neogene and Quaternary volcanic rocks and hydrothermal vein systems, together with a distinctive Cretaceous terrane of the Franciscan Complex (the Permanente terrane), exhibits about 160 to 170 km of cumulative dextral offset across faults of the East San Francisco Bay Region (ESFBR) fault system. The offset hydrothermal veins and volcanic rocks range in age from .01 Ma at the northwest end to about 17.6 Ma at the southeast end. In the fault block between the San Andreas and ESFBR fault systems, where volcanic rocks are scarce, hydrothermal vein system ages clearly indicate that the northward younging thermal overprint affected these rocks beginning about 18 Ma. The age progression of these volcanic rocks and hydrothermal vein systems is consistent with previously proposed models that relate northward propagation of the San Andreas transform to the opening of an asthenospheric window beneath the North American plate margin in the wake of subducting lithosphere. The similarity in the amount of offset of the Permanente terrane across the ESFBR fault system to that derived by restoring continuity in the northward younging age progression of volcanic rocks and hydrothermal veins suggests a model in which 80-110 km of offset are taken up 8 to 6 Ma on a fault aligned with the Bloomfield-Tolay-Franklin-Concord-Sunol-Calaveras faults. An additional 50-70 km of cumulative slip are taken up ??? 6 Ma by the Rogers Creek-Hayward and Concord-Franklin-Sunol-Calaveras faults. An alternative model in which the Permanente terrane is offset about 80 km by pre-Miocene faults does not adequately restore the distribution of 8-12 Ma volcanic rocks and hydrothermal veins to a single northwardly younging age trend. If 80-110 km of slip was taken up by the ESFBR fault system between 8 and 6 Ma, dextral slip rates were 40-55 mm/yr. Such high rates might occur if the ESFBR fault system rather than the San Andreas fault acted as the transform margin at this time

  6. The Purisima Formation and related rocks (upper Miocene - Pliocene), greater San Francisco Bay area, central California; review of literature and USGS collection now housed at the Museum of Paleontology, University of California, Berkeley

    Science.gov (United States)

    Powell, C.L.

    1998-01-01

    Sedimentary rocks more than 1.6 kilometers thick are attributed to the upper Miocene to upper Pliocene Purisima Formation in the greater San Francisco Bay area. These rocks occur as scattered, discontinuous outcrops from Point Reyes National Seashore in the north to south of Santa Cruz. Lithologic divisions of the Formation appear to be of local extent and are of limited use in correlating over this broad area. The Purisima Formation occurs in several fault-bounded terranes which demonstrate different stratigraphic histories and may be found to represent more than a single depositional basin. The precise age and stratigraphic relationship of these scattered outcrops are unresolved and until they are put into a stratigraphic and paleogeographic context the tectonic significance of the Purisima Foramtion can only be surmised. This paper will attempt to resolve some of these problems. Mollusks and echinoderms are recorded from the literature and more than 70 USGS collections that have not previously been reported. With the exception of one locality, the faunas suggest deposition in normal marine conditions at water depths of less than 50 m and with water temperatures the same or slightly cooler than exist along the present coast of central California. The single exception is a fauna from outcrops between Seal Cove and Pillar Point, where both mollusks and foraminifers suggest water depths greater than 100 m. Three molluscan faunas, the La Honda, the Pillar Point, and the Santa Cruz, are recognized based on USGS collections and published literature for the Purisima Formation. These biostratigraphically distinct faunas aid in the correlation of the scattered Purisima Formation outcrops. The lowermost La Honda fauna suggests shallow-water depths and an age of late Miocene to early Pliocene. This age is at odds with a younger age determination from an ash bed in the lower Purisima Formation along the central San Mateo County coast. The Pillar Point fauna contains only a

  7. Box Model of a Series of Salt Ponds, as Applied to the Alviso Salt Pond Complex, South San Francisco Bay, California

    Science.gov (United States)

    Lionberger, Megan A.; Schoellhamer, David H.; Shellenbarger, Gregory; Orlando, James L.; Ganju, Neil K.

    2007-01-01

    This report documents the development and application of a box model to simulate water level, salinity, and temperature of the Alviso Salt Pond Complex in South San Francisco Bay. These ponds were purchased for restoration in 2003 and currently are managed by the U.S. Fish and Wildlife Service to maintain existing wildlife habitat and prevent a build up of salt during the development of a long-term restoration plan. The model was developed for the purpose of aiding pond managers during the current interim management period to achieve these goals. A previously developed box model of a salt pond, SPOOM, which calculates daily pond volume and salinity, was reconfigured to simulate multiple connected ponds and a temperature subroutine was added. The updated model simulates rainfall, evaporation, water flowing between the ponds and the adjacent tidal slough network, and water flowing from one pond to the next by gravity and pumps. Theoretical and measured relations between discharge and corresponding differences in water level are used to simulate most flows between ponds and between ponds and sloughs. The principle of conservation of mass is used to calculate daily pond volume and salinity. The model configuration includes management actions specified in the Interim Stewardship Plan for the ponds. The temperature subroutine calculates hourly net heat transfer to or from a pond resulting in a rise or drop in pond temperature and daily average, minimum, and maximum pond temperatures are recorded. Simulated temperature was compared with hourly measured data from pond 3 of the Napa?Sonoma Salt Pond Complex and monthly measured data from pond A14 of the Alviso Salt-Pond Complex. Comparison showed good agreement of measured and simulated pond temperature on the daily and monthly time scales.

  8. Estimating juvenile Chinook salmon (Oncorhynchus tshawytscha) abundance from beach seine data collected in the Sacramento–San Joaquin Delta and San Francisco Bay, California

    Science.gov (United States)

    Perry, Russell W.; Kirsch, Joseph E.; Hendrix, A. Noble

    2016-06-17

    Resource managers rely on abundance or density metrics derived from beach seine surveys to make vital decisions that affect fish population dynamics and assemblage structure. However, abundance and density metrics may be biased by imperfect capture and lack of geographic closure during sampling. Currently, there is considerable uncertainty about the capture efficiency of juvenile Chinook salmon (Oncorhynchus tshawytscha) by beach seines. Heterogeneity in capture can occur through unrealistic assumptions of closure and from variation in the probability of capture caused by environmental conditions. We evaluated the assumptions of closure and the influence of environmental conditions on capture efficiency and abundance estimates of Chinook salmon from beach seining within the Sacramento–San Joaquin Delta and the San Francisco Bay. Beach seine capture efficiency was measured using a stratified random sampling design combined with open and closed replicate depletion sampling. A total of 56 samples were collected during the spring of 2014. To assess variability in capture probability and the absolute abundance of juvenile Chinook salmon, beach seine capture efficiency data were fitted to the paired depletion design using modified N-mixture models. These models allowed us to explicitly test the closure assumption and estimate environmental effects on the probability of capture. We determined that our updated method allowing for lack of closure between depletion samples drastically outperformed traditional data analysis that assumes closure among replicate samples. The best-fit model (lowest-valued Akaike Information Criterion model) included the probability of fish being available for capture (relaxed closure assumption), capture probability modeled as a function of water velocity and percent coverage of fine sediment, and abundance modeled as a function of sample area, temperature, and water velocity. Given that beach seining is a ubiquitous sampling technique for

  9. Simulation of climate change in San Francisco Bay Basins, California: Case studies in the Russian River Valley and Santa Cruz Mountains

    Science.gov (United States)

    Flint, Lorraine E.; Flint, Alan L.

    2012-01-01

    As a result of ongoing changes in climate, hydrologic and ecologic effects are being seen across the western United States. A regional study of how climate change affects water resources and habitats in the San Francisco Bay area relied on historical climate data and future projections of climate, which were downscaled to fine spatial scales for application to a regional water-balance model. Changes in climate, potential evapotranspiration, recharge, runoff, and climatic water deficit were modeled for the Bay Area. In addition, detailed studies in the Russian River Valley and Santa Cruz Mountains, which are on the northern and southern extremes of the Bay Area, respectively, were carried out in collaboration with local water agencies. Resource managers depend on science-based projections to inform planning exercises that result in competent adaptation to ongoing and future changes in water supply and environmental conditions. Results indicated large spatial variability in climate change and the hydrologic response across the region; although there is warming under all projections, potential change in precipitation by the end of the 21st century differed according to model. Hydrologic models predicted reduced early and late wet season runoff for the end of the century for both wetter and drier future climate projections, which could result in an extended dry season. In fact, summers are projected to be longer and drier in the future than in the past regardless of precipitation trends. While water supply could be subject to increased variability (that is, reduced reliability) due to greater variability in precipitation, water demand is likely to steadily increase because of increased evapotranspiration rates and climatic water deficit during the extended summers. Extended dry season conditions and the potential for drought, combined with unprecedented increases in precipitation, could serve as additional stressors on water quality and habitat. By focusing on the

  10. Record-high specific conductance and temperature in San Francisco Bay during water year 2014

    Science.gov (United States)

    Downing-Kunz, Maureen; Work, Paul; Shellenbarger, Gregory

    2015-11-18

    The U.S. Geological Survey (USGS) has operated a water-quality monitoring network in San Francisco Bay since the late 1980s (Buchanan and others, 2015). This network includes 19 stations in the bay; currently, 8 stations are in operation (fig. 1). All eight stations are equipped with specific conductance (which can be related to salinity) and water-temperature sensors that record measurements at 15-minute intervals. Water quality in the bay constantly changes with the ocean tides and with seasonal and interannual differences in river inflows. Our network was designed to observe and characterize some of these changes in the bay across space and over time. Our data demonstrated a high degree of variability both in specific conductance and temperature at time scales from tidal to annual and also revealed longer term changes that are likely to influence overall environmental health in the bay (San Francisco Estuary Institute, 2014). Figure 1. Locations of fixed water-quality monitoring stations in San Francisco Bay, California, for the 2014 water year (October 1, 2013 to September 30, 2014).

  11. The ecology of the soft-bottom benthos of San Francisco Bay: a community profile

    Science.gov (United States)

    Nichols, Frederic H.; Pamatmat, Mario M.

    1988-01-01

    This profile, part of a series of profiles concerning coastal habitats of the United States, is a detailed examination of the soft-bottom benthos of San Francisco Bay. A U.S. Fish and Wildlife Service and California Department of Fish and Game report (1979) entitled "Protection and Restoration of San Francisco Bay Fish and Wildlife Habitat" provides clear recognition of the importance of intertidal and subtidal soft-bottom habitats and their associated organisms to the bay's birds and fishes and to the overall functioning of the estuary. The purpose of this profile is to provide a description of the structure and functioning of the benthic community in San Francisco Bay (exclusive of its tidal marshes, which are discussed by M. Josselyn [1983] in another profile). The habitats covered in this volume include all nonvegetated soft-bottom intertidal and subtidal areas of the bay between the Golden Gate and the mouths of the Sacramento and San Joaquin Rivers to the northeast, and to the southern extremity of the bay.

  12. What is causing the phytoplankton increase in San Francisco Bay?

    Science.gov (United States)

    Cloern, J.E.; Jassby, A.D.; Schraga, T.S.; Dallas, K.L.

    2006-01-01

    The largest living component of San Francisco Bay is the phytoplankton, a suspension of microscopic cells that convert sunlight energy into new living biomass through the same process of photosynthesis used by land plants. This primary production is the ultimate source of food for clams, zooplankton, crabs, sardines, halibut, sturgeon, diving ducks, pelicans, and harbor seals. From measurements made in 1980, we estimated that phytoplankton primary production in San Francisco Bay was about 200,000 tons of organic carbon per year (Jassby et al. 1993). This is equivalent to producing the biomass of 5500 adult humpback whales, or the calories to feed 1.8 million people. These numbers may seem large, but primary production in San Francisco Bay is low compared to many other nutrient-enriched estuaries.

  13. Earthquake outlook for the San Francisco Bay region 2014–2043

    Science.gov (United States)

    Aagaard, Brad T.; Blair, James Luke; Boatwright, John; Garcia, Susan H.; Harris, Ruth A.; Michael, Andrew J.; Schwartz, David P.; DiLeo, Jeanne S.; Jacques, Kate; Donlin, Carolyn

    2016-06-13

    Using information from recent earthquakes, improved mapping of active faults, and a new model for estimating earthquake probabilities, the 2014 Working Group on California Earthquake Probabilities updated the 30-year earthquake forecast for California. They concluded that there is a 72 percent probability (or likelihood) of at least one earthquake of magnitude 6.7 or greater striking somewhere in the San Francisco Bay region before 2043. Earthquakes this large are capable of causing widespread damage; therefore, communities in the region should take simple steps to help reduce injuries, damage, and disruption, as well as accelerate recovery from these earthquakes.

  14. Folds--Offshore of San Francisco Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for folds for the geologic and geomorphic map of the Offshore of San Francisco map area, California. The vector data file is...

  15. Faults--Offshore of San Francisco Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for faults for the geologic and geomorphic map of the Offshore San Francisco map area, California. The vector data file is included...

  16. Faults--Offshore of San Francisco Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for faults for the geologic and geomorphic map of the Offshore San Francisco map area, California. The vector data file is included...

  17. Folds--Offshore of San Francisco Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for folds for the geologic and geomorphic map of the Offshore of San Francisco map area, California. The vector data file is...

  18. Backscatter C [8101]--Offshore of San Francisco, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of San Francisco map area, California. Backscatter data are provided as separate...

  19. Backscatter A [8101]--Offshore of San Francisco, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of San Francisco map area, California. Backscatter data are provided as separate...

  20. Backscatter C [8101]--Offshore of San Francisco, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of San Francisco map area, California. Backscatter data are provided as separate...

  1. Backscatter B [8101]--Offshore of San Francisco, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of San Francisco map area, California. Backscatter data are provided as separate...

  2. Backscatter A [8101]--Offshore of San Francisco, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of San Francisco map area, California. Backscatter data are provided as separate...

  3. Backscatter D [7125]--Offshore of San Francisco, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of San Francisco map area, California. Backscatter data are provided as separate...

  4. San Francisco, California Tsunami Forecast Grids for MOST Model

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The San Francisco, California Forecast Model Grids provides bathymetric data strictly for tsunami inundation modeling with the Method of Splitting Tsunami (MOST)...

  5. Backscatter B [8101]--Offshore of San Francisco, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of San Francisco map area, California. Backscatter data are provided as separate...

  6. Faults--Offshore of San Francisco Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for faults for the geologic and geomorphic map of the Offshore San Francisco map area, California. The vector data file is...

  7. Record-high specific conductance and water temperature in San Francisco Bay during water year 2015

    Science.gov (United States)

    Work, Paul; Downing-Kunz, Maureen; Livsey, Daniel

    2017-02-22

    The San Francisco estuary is commonly defined to include San Francisco Bay (bay) and the adjacent Sacramento–San Joaquin River Delta (delta). The U.S. Geological Survey (USGS) has operated a high-frequency (15-minute sampling interval) water-quality monitoring network in San Francisco Bay since the late 1980s (Buchanan and others, 2014). This network includes 19 stations at which sustained measurements have been made in the bay; currently, 8 stations are in operation (fig. 1). All eight stations are equipped with specific conductance (which can be related to salinity) and water-temperature sensors. Water quality in the bay constantly changes as ocean tides force seawater in and out of the bay, and river inflows—the most significant coming from the delta—vary on time scales ranging from those associated with storms to multiyear droughts. This monitoring network was designed to observe and characterize some of these changes in the bay across space and over time. The data demonstrate a high degree of variability in both specific conductance and temperature at time scales from tidal to annual and also reveal longer-term changes that are likely to influence overall environmental health in the bay.In water year (WY) 2015 (October 1, 2014, through September 30, 2015), as in the preceding water year (Downing-Kunz and others, 2015), the high-frequency measurements revealed record-high values of specific conductance and water temperature at several stations during a period of reduced freshwater inflow from the delta and other tributaries because of persistent, severe drought conditions in California. This report briefly summarizes observations for WY 2015 and compares them to previous years that had different levels of freshwater inflow.

  8. Ancient blue oaks reveal human impact on San Francisco Bay salinity

    Science.gov (United States)

    Stahle, David W.; Therrell, Matthew D.; Cleaveland, Malcolm K.; Cayan, Daniel R.; Dettinger, Michael D.; Knowles, Noah

    2001-01-01

    San Francisco Bay is one of the most important estuaries on the west coast of the Americas. Its water quality is controlled primarily by streamflow from the Sacramento and San Joaquin rivers. In fact, freshwater inflow from the Sacramento-San Joaquin Delta explains 86% of the salinity variability at the mouth of the San Francisco Bay estuary [Peterson et al., 1989]. The massive diversion of streamflow by the California State Water Project and the Central Valley Project, part of the largest manmade water control system on Earth [Reisner, 1988], has raised salinity in the estuary on daily, seasonal, and annual timescales [Nichols et al., 1986; Peterson et al., 1989].

  9. Broadband Ground Motion Estimates for Scenario Earthquakes in the San Francisco Bay Region

    Science.gov (United States)

    Graves, R. W.

    2006-12-01

    Using broadband (0-10 Hz) simulation procedures, we are assessing the ground motions that could be generated by different earthquake scenarios occurring on major strike-slip faults of the San Francisco Bay region. These simulations explicitly account for several important ground motion features, including rupture directivity, 3D basin response, and the depletion of high frequency ground motions that occurs for surface rupturing events. This work compliments ongoing USGS efforts to quantify the ground shaking hazards throughout the San Francisco Bay region. These efforts involve development and testing of a 3D velocity model for northern California (USGS Bay Area Velocity Model, version 05.1.0) using observations from the 1989 Loma Prieta earthquake, characterization of 1906 rupture scenarios and ground motions, and the development and analysis of rupture scenarios on other Bay Area faults. The adequacy of the simulation model has been tested using ground motion data recorded during the 1989 Loma Prieta earthquake and by comparison with the reported intensity data from the 1906 earthquake. Comparisons of the simulated broadband (0-10 Hz) ground motions with the recorded motions for the 1989 Loma Prieta earthquake demonstrate that the modeling procedure matches the observations without significant bias over a broad range of frequencies, site types, and propagation distances. The Loma Prieta rupture model is based on a wavenumber-squared refinement of the Wald et al (1991) slip distribution, with the rupture velocity set at 75 percent of the local shear wave velocity and a Kostrov-type slip function having a rise time of about 1.4 sec. Simulations of 1906 scenario ruptures indicate very strong directivity effects to the north and south of the assumed epicenter, adjacent to San Francisco. We are currently analyzing additional earthquake scenarios on the Hayward-Rodgers Creek and San Andreas faults in order to provide a more comprehensive framework for assessing

  10. Waterbird nest monitoring program in San Francisco Bay (2005-10)

    Science.gov (United States)

    Ackerman, Joshua T.; Herzog, Mark P.

    2012-01-01

    Historically, Forster's Terns (Sterna forsteri), American Avocets (Recurvirostra americana), and Black-necked Stilts (Himantopus mexicanus) were uncommon residents of San Francisco Bay, California (Grinnell and others, 1918; Grinnell and Wythe, 1927; Sibley, 1952). Presently, however, avocets and stilts are the two most abundant breeding shorebirds in San Francisco Bay (Stenzel and others, 2002; Rintoul and others, 2003). More than 4,000 avocets and 1,000 stilts, roughly 20 percent of their San Francisco Bay wintering populations, breed within the estuary, making San Francisco Bay the largest breeding area for these species on the Pacific Coast (Stenzel and others, 2002; Rintoul and others, 2003). Forster's Terns were first observed breeding in the San Francisco Bay in 1948 (110 nests); they had increased to over 4000 individuals by the 1980s (Sibley, 1952; Gill, 1977; Harvey and others, 1992; Carter and others, 1990) and were estimated at 2000-3000 for 1998-2002; (Strong and others, 2004). It is hypothesized that the relatively large size of the current waterbird breeding populations is a result of the creation of artificial salt evaporation ponds from the 1930s through the 1950s (Gill, 1977; Goals Project, 1999). Until recently, these salt ponds and associated islands used by waterbirds for nesting have been managed relatively similarly and have supported large breeding waterbird populations. Recently, the South Bay Salt Pond Restoration Project has implemented plans to convert 50-90 percent of the 15,000 acres of salt ponds in the South San Francisco Bay back to tidal marsh habitat. Therefore, there is concern that the Restoration Project, while benefiting other native species, could negatively influence local breeding populations of waterbirds that are reliant on salt pond habitats for both breeding and foraging. A primary goal of the South Bay Salt Pond Restoration Project is to maintain current breeding waterbird populations (South Bay Salt Pond Long

  11. Talus Lex: Regulatory Approaches to Reducing Mercury Concentrations in San Francisco Bay Fish.

    Science.gov (United States)

    Abu-Saba, D. E.; Flegal, D. R.; Ganguli, P. M.; Whyte, D. C.; Mumley, D. E.; Mason, D. P.

    2001-12-01

    The history of mercury in California is recorded in the sediments of San Francisco Bay. The Bay is downstream of 40 percent of the land area of California. Its watershed receives 80 percent of the rainfall in the State, because it rains more in the north. Three billion kilograms of sediments are annually flushed from the Central Valley watershed and deposited in San Francisco Bay. Because mercury preferentially binds to sediments, we calculate mercury loads to the Bay by considering how various sources affect mercury concentrations in Bay sediments. During and after the Gold Rush, over seventy thousand tons of mercury was produced in Coast Range cinnabar mines. Much of this mercury was used as quicksilver to extract gold from placer formations in the Sierra foothills, and later in the production of munitions, electronics, health care and commercial products. Today, we can see the legacy of mining sources, from both remote and local watersheds, superimposed on air deposition, the climate and geography of California, heavily managed water supply and flood control projects, wetland restoration and rehabilitation, urbanization, wastewaster discharge and water reclamation. We already regulate wastewater and urban runoff through issuance of permits and waste discharge requirements. We can regulate mercury inputs from inoperative mines by demonstrating the link between mercury-polluted sediments and violation of existing numeric water quality objectives. We can use the same approach to regulate the disposal of mercury-containing electronic devices. But to reduce mercury levels in fish, we will also have to consider controllable water quality factors that promote mercury methylation in the aquatic ecosystem. Some of these water quality factors are already subject to regulation. For example, we can show that mercury methylation in the northern reach of the Bay increases when dissolved oxygen drops below 6 mg/L; current regulations require dissolved oxygen concentrations of

  12. Community Heavy Metal Exposure, San Francisco, California

    Science.gov (United States)

    Chavez, A.; Devine, M.; Ho, T.; Zapata, I.; Bissell, M.; Neiss, J.

    2008-12-01

    Heavy metals are natural elements that generally occur in minute concentrations in the earth's crust. While some of these elements, in small quantities, are vital to life, most are harmful in larger doses. Various industrial and agricultural processes can result in dangerously high concentrations of heavy metals in our environment. Consequently, humans can be exposed to unsafe levels of these elements via the air we breathe, the water and food we consume, and the many products we use. During a two week study we collected numerous samples of sediments, water, food, and household items from around the San Francisco Bay Area that represent industrial, agricultural, and urban/residential settings. We analyzed these samples for Mercury (Hg), Lead (Pb), and Arsenic (As). Our goal was to examine the extent of our exposure to heavy metals in our daily lives. We discovered that many of the common foods and materials in our lives have become contaminated with unhealthy concentrations of these metals. Of our food samples, many exceeded the EPA's Maximum Contaminant Levels (MCL) set for each metal. Meats (fish, chicken, and beef) had higher amounts of each metal than did non-meat items. Heavy metals were also prevalent in varying concentrations in the environment. While many of our samples exceeded the EPA's Sediment Screening Level (SSL) for As, only two other samples surpassed the SSL set for Pb, and zero of our samples exceeded the SSL for Hg. Because of the serious health effects that can result from over-exposure to heavy metals, the information obtained in this study should be used to influence our future dietary and recreational habits.

  13. Deep bore hole instrumentation along San Francisco Bay Bridges

    Energy Technology Data Exchange (ETDEWEB)

    Bakun, W.; Bowman, J.; Clymer, R.; Foxall, W.; Hipley, P.; Hollfelder, J.; Hutchings, L.; Jarpe, S.; Kasameyer, P.; McEvilly, T.; Mualchin, L.; Palmer, M.

    1998-10-01

    The Bay Bridges down hole network consists of sensors in bore holes that are drilled 100 ft. into bedrock around and in the San Francisco Bay. Between 2 and 8 instruments have been spaced along the Dumbarton, San Mateo, Bay, and San Rafael bridges. The instruments will provide multiple use data that is important to geotechnical, structural engineering, and seismological studies. The holes are between 100 and 1000 ft deep and were drilled by Caltrans. There are twenty- one sensor packages at fifteen sites. Extensive financial support is being contributed by Caltrans, UCB, LBL, LLNL-LDRD, U.C. Campus/Laboratory Collaboration (CLC) program, and USGS. The down hole instrument package contains a three component HS-1 seismometer and three orthogonal Wilcox 73 1 accelerometers, and is capable of recording a micro g from local M = 1.0 earthquakes to 0.5 g strong ground motion form large Bay Area earthquakes.

  14. Microbial diversity in restored wetlands of San Francisco Bay

    Energy Technology Data Exchange (ETDEWEB)

    Theroux, Susanna [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Hartman, Wyatt [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; He, Shaomei [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Univ. of Wisconsin, Madison, WI (United States); Tringe, Susannah [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.

    2013-12-09

    Wetland ecosystems may serve as either a source or a sink for atmospheric carbon and greenhouse gases. This delicate carbon balance is influenced by the activity of belowground microbial communities that return carbon dioxide and methane to the atmosphere. Wetland restoration efforts in the San Francisco Bay-Delta region may help to reverse land subsidence and possibly increase carbon storage in soils. However, the effects of wetland restoration on microbial communities, which mediate soil metabolic activity and carbon cycling, are poorly studied. In an effort to better understand the underlying factors which shape the balance of carbon flux in wetland soils, we targeted the microbial communities in a suite of restored and historic wetlands in the San Francisco Bay-Delta region. Using DNA and RNA sequencing, coupled with greenhouse gas monitoring, we profiled the diversity and metabolic potential of the wetland soil microbial communities along biogeochemical and wetland age gradients. Our results show relationships among geochemical gradients, availability of electron acceptors, and microbial community composition. Our study provides the first genomic glimpse into microbial populations in natural and restored wetlands of the San Francisco Bay-Delta region and provides a valuable benchmark for future studies.

  15. A review of benthic faunal surveys in San Francisco Bay

    Science.gov (United States)

    Nichols, Frederic H.

    1973-01-01

    During the past 60 years, considerable effort has been expended in studies of the relations of the biotic community and physicochemical characteristics of San Francisco Bay water. In very recent years these studies have emphasized the relations between the 'state of health' of bottom-living invertebrates (the benthos) and the levels of pollutants in the bay. Benthic organisms, generally sessile, are unable to escape deleterious environmental changes, and they reflect these changes in alterations of normal species composition of assemblages and species abundance. Data that expands understanding of these relations in urbanized areas such as San Francisco Bay are critical. Because of the implications of such data in control of water quality, the U.S. Geological Survey undertook a review of the results and major conclusions of San Francisco Bay benthic surveys. The size and species composition of faunal assemblages are largely controlled by the salinity of the water, the texture of the bottom sediments, and locally by wastes discharged into the bay. Efforts to describe the structure and function of benthic communities of the bay and to quantify the effects of waste discharge on them have been hampered by inconsistent and often faulty sampling methodology and species identification. Studies made show a lack of information on the normal life processes of the organisms concerned. The diversity index (a mathematical expression of the number of kinds of organisms present at a location), commonly used to describe the 'health' of the benthic community, has been employed without regard for the need for standardizing methodology and species identifications or for understanding natural biological processes that affect such mathematical indices. There are few reliable quantitative data on the distribution of benthic organisms in San Francisco Bay with which future assessments of the 'health' of the benthic community might be compared. Methods for study of the benthos must be

  16. Seasonal cycles of zooplankton from San Francisco Bay

    Science.gov (United States)

    Ambler, Julie W.; Cloern, James E.; Hutchinson, Anne

    1985-01-01

    The two estuarine systems composing San Francisco Bay have distinct zooplankton communities and seasonal population dynamics. In the South Bay, a shallow lagoon-type estuary, the copepods Acartia spp. and Oithona davisae dominate. As in estuaries along the northeast coast of the U.S., there is a seasonal succession involving the replacement of a cold-season Acartia species (A. clausi s.l.) by a warm-season species (A. californiensis), presumably resulting from the differential production and hatching of dormant eggs. Oithona davisae is most abundant during the fall. Copepods of northern San Francisco Bay, a partially-mixed estuary of the Sacramento-San Joaquin Rivers, organize into discrete populations according to salinity distribution: Sinocalanus doerrii (a recently introduced species) at the riverine boundary, Eurytemora affinis in the oligohaline mixing zone, Acartia spp. in polyhaline waters (18–30\\%), and neritic species (e.g., Paracalanus parvus) at the seaward boundary. Sinocalanus doerrii and E. affinis are present year-round. Acartia clausi s.l.is present almost year-round in the northern reach, and A. californiensis occurs only briefly there in summer-fall. The difference in succession of Acartia species between the two regions of San Francisco Bay may reflect differences in the seasonal temperature cycle (the South Bay warms earlier), and the perennial transport of A. clausi s.l. into the northern reach from the seaward boundary by nontidal advection.

  17. Environmental extremes and biotic interactions facilitate depredation of endangered California Ridgway’s rail in a San Francisco Bay tidal marsh

    Science.gov (United States)

    Overton, Cory T.; Bobzien, Steven; Grefsrud, Marcia

    2016-01-01

    On 23 December 2015 while performing a high tide population survey for endangered Ridgway’s rails (Rallus obsoletus obsoletus; formerly known as the California clapper rail) and other rail species at Arrowhead Marsh, Martin Luther King Jr. Regional Shoreline, Oakland, California, the authors observed a series of species interactions resulting in the predation of a Ridgway’s rail by an adult female peregrine falcon (Falco peregrinus). High tide surveys are performed during the highest tides of the year when tidal marsh vegetation at Arrowhead Marsh becomes inundated, concentrating the tidal marsh obligate species into the limited area of emergent vegetation remaining as refuge cover. Annual mean tide level (elevation referenced relative to mean lower low water) at Arrowhead Marsh is 1.10 m, mean higher high water is 2.04 m (NOAA National Ocean Service 2014) and the average elevation of the marsh surface is 1.60 m (Overton et al. 2014). Tidal conditions on the day of the survey were predicted to be 2.42 m. Observed tides at the nearby Alameda Island tide gauge were 8 cm higher than predicted due to a regional low-pressure system and warmer than average sea surface temperatures (NOAA National Ocean Service 2014). The approximately 80 cm deep inundation of the marsh plain was sufficient to completely submerge tidal marsh vegetation and effectively remove 90% of refugia habitats.

  18. Shifting shoals and shattered rocks : How man has transformed the floor of west-central San Francisco Bay

    Science.gov (United States)

    Chin, John L.; Wong, Florence L.; Carlson, Paul R.

    2004-01-01

    San Francisco Bay, one of the world's finest natural harbors and a major center for maritime trade, is referred to as the 'Gateway to the Pacific Rim.' The bay is an urbanized estuary that is considered by many to be the major estuary in the United States most modified by man's activities. The population around the estuary has grown rapidly since the 1850's and now exceeds 7 million people. The San Francisco Bay area's economy ranks as one of the largest in the world, larger even than that of many countries. More than 10 million tourists are estimated to visit the bay region each year. The bay area's population and associated development have increasingly changed the estuary and its environment. San Francisco Bay and the contiguous Sacramento-San Joaquin Delta encompass roughly 1,600 square miles (4,100 km2) and are the outlet of a major watershed that drains more than 40 percent of the land area of the State of California. This watershed provides drinking water for 20 million people (two thirds of the State's population) and irrigates 4.5 million acres of farmland and ranchland. During the past several decades, much has been done to clean up the environment and waters of San Francisco Bay. Conservationist groups have even bought many areas on the margins of the bay with the intention of restoring them to a condition more like the natural marshes they once were. However, many of the major manmade changes to the bay's environment occurred so long ago that the nature of them has been forgotten. In addition, many changes continue to occur today, such as the introduction of exotic species and the loss of commercial and sport fisheries because of declining fish populations. The economy and population of the nine counties that surround the bay continue to grow and put increasing pressure on the bay, both direct and indirect. Therefore, there are mixed signals for the future health and welfare of San Francisco Bay. The San Francisco Bay estuary consists of three

  19. Anthropogenic influence on recent bathymetric change in west-central San Francisco Bay

    Science.gov (United States)

    Barnard, Patrick L.; Kvitek, Rikk G.

    2010-01-01

    Two multibeam sonar surveys of west-central San Francisco Bay, California, were conducted in 1997 and 2008. Bathymetric change analysis between the two surveys indicates a loss of 14.1 million cubic meters (-3.1 cm/yr-1) of sediment during this time period, representing an approximately three-fold acceleration of the rate that was observed from prior depth change analysis from 1947 to 1979 for all of Central Bay, using more spatially coarse National Ocean Service (NOS) soundings. The portions of the overlapping survey areas between 1997 and 2008 designated as aggregate mining lease sites lost sediment at five times the rate of the remainder of west-central San Francisco Bay. Despite covering only 28% of the analysis area, volume change within leasing areas accounted for 9.2 million cubic meters of sediment loss, while the rest of the area lost 4.9 million cubic meters of sediment. The uncertainty of this recent analysis is more tightly constrained due to more stringent controls on vertical and horizontal position via tightly coupled, inertially aided differential Global Positioning Systems (GPS) solutions for survey vessel trajectory that virtually eliminate inaccuracies from traditional tide modeling and vessel motion artifacts. Further, quantification of systematic depth measurement error can now be calculated through comparison of static surfaces (e.g., bedrock) between surveys using seafloor habitat maps based on acoustic backscatter measurements and ground-truthing with grab samples and underwater video. Sediment loss in the entire San Francisco Bay Coastal System during the last half-century,as estimated from a series of bathymetric change studies, is 240 million cubic meters, and most of this is believed to be coarse sediment (i.e., sand and gravel) from Central Bay and the San Francisco Bar, which is likely to limit the sand supply to adjacent, open-coast beaches. This hypothesis is supported by a calibrated numerical model in a related study that indicates

  20. Geology and geochemistry of volcanic centers within the eastern half of the Sonoma volcanic field, northern San Francisco Bay region, California

    Science.gov (United States)

    Sweetkind, Donald S.; Rytuba, James J.; Langenheim, V.E.; Fleck, Robert J.

    2011-01-01

    Volcanic rocks in the Sonoma volcanic field in the northern California Coast Ranges contain heterogeneous assemblages of a variety of compositionally diverse volcanic rocks. We have used field mapping, new and existing age determinations, and 343 new major and trace element analyses of whole-rock samples from lavas and tuff to define for the first time volcanic source areas for many parts of the Sonoma volcanic field. Geophysical data and models have helped to define the thickness of the volcanic pile and the location of caldera structures. Volcanic rocks of the Sonoma volcanic field show a broad range in eruptive style that is spatially variable and specific to an individual eruptive center. Major, minor, and trace-element geochemical data for intracaldera and outflow tuffs and their distal fall equivalents suggest caldera-related sources for the Pinole and Lawlor Tuffs in southern Napa Valley and for the tuff of Franz Valley in northern Napa Valley. Stratigraphic correlations based on similarity in eruptive sequence and style coupled with geochemical data allow an estimate of 30 km of right-lateral offset across the West Napa-Carneros fault zones since ~5 Ma.

  1. Diversity of Denitrifying Bacteria in the San Francisco Bay

    Science.gov (United States)

    Atluri, A.; Lee, J.; Francis, C. A.

    2012-12-01

    We compared the diversity of communities of denitrifying bacteria from the San Francisco Bay to investigate whether environmental factors affect diversity. To do this, we studied the sequence diversity of the marker gene nirK. nirK codes for the enzyme nitrite reductase which helps reduce nitrite to nitric oxide, an important step in denitrification. Sediment samples were collected spatially from five different locations and temporally during the four different seasons along a salinity gradient in the bay. After collecting samples and extracting DNA from them, we used PCR to amplify our gene of interest, created clone libraries for sequencing, and compared phylogenetic trees from the different communities. Based on several phylogenetic analyses on our tree and environments, we saw that denitrifying bacteria from the North and Central Bay form distinct spatial clusters; Central Bay communities are very similar to each other, while communities from the North Bay are more distinct from each other and from communities in the Central Bay. Bacteria from site 8.1M (Carquinez Strait) showed the most cm-scale spatial diversity, and there was the most species richness during the winter. All this suggests that diversity of communities of denitrifying bacteria may be affected by spatial and temporal environmental factors.

  2. Don Edwards San Francisco Bay National Wildlife Refuge: Annual Narrative Report: Calendar Year 2000

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Don Edwards San Francisco Bay NWR, Antioch Dunes NWR, Farallon NWR, San Pablo Bay NWR, Ellicot Slough NWR, Salinas River NWR, and...

  3. Dioxin toxin equivalents, PCBs, and PBDEs in eggs of avian wildlife of San Francisco Bay

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — San Francisco Bay (Bay) is considered an impaired waterbody under section 303 (d) of the Clean Water Act due to polychlorinated biphenyls (PCB) and 2, 3, 7,...

  4. San Francisco Bay National Wildlife Refuge: Annual Narrative Report: Calendar Year 1990

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for San Francisco Bay NWR, San Pablo Bay NWR, Antioch Dunes NWR, Farallon NWR, Ellicott Slough NWR, and Salinas River NWR outlines...

  5. San Francisco Bay National Wildlife Refuge Complex: Annual Narrative Report: Calendar Year 1989

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for San Francisco Bay NWR, San Pablo Bay NWR, Antioch Dunes NWR, Farallon NWR, Ellicott Slough NWR, and Salinas River NWR outlines...

  6. Near-field receiving water monitoring of trace metals and a benthic community near the Palo Alto Regional Water Quality Control Plant in south San Francisco Bay, California: 2014

    Science.gov (United States)

    Cain, Daniel J.; Thompson, Janet K.; Crauder, Jeff; Parcheso, Francis; Stewart, Robin; Kleckner, Amy E.; Dyke, Jessica; Hornberger, Michelle I.; Luoma, Samuel N.

    2015-01-01

    Trace-metal concentrations in sediment and in the clam Macoma petalum (formerly reported as Macoma balthica), clam reproductive activity, and benthic macroinvertebrate community structure were investigated in a mudflat 1 kilometer (km) south of the discharge of the Palo Alto Regional Water Quality Control Plant (PARWQCP) in South San Francisco Bay, Calif. This report includes the data collected by U.S. Geological Survey (USGS) scientists for the period January 2014 to December 2014. These append to long-term datasets extending back to 1974, and serve as the basis for the City of Palo Alto’s Near-Field Receiving Water Monitoring Program, initiated in 1994. 

  7. Near-field receiving water monitoring of trace metals and a benthic community near the Palo Alto Regional Water Quality Control Plant in South San Francisco Bay, California-2010

    Science.gov (United States)

    Dyke, Jessica; Parcheso, Francis; Thompson, Janet K.; Cain, Daniel J.; Luoma, Samuel N.; Hornberger, Michelle I.

    2011-01-01

    Trace-metal concentrations in sediment and in the clam Macoma petalum (formerly reported as Macoma balthica), clam reproductive activity, and benthic macroinvertebrate community structure were investigated in a mudflat 1 kilometer south of the discharge of the Palo Alto Regional Water Quality Control Plant (PARWQCP) in South San Francisco Bay, Calif. This report includes the data collected for the period January 2010 to December 2010 and extends a critical long-term biogeochemical record that dates back to 1974. These data serve as the basis for the City of Palo Alto's Near-Field Receiving Water Monitoring Program initiated in 1994.

  8. Near-Field Receiving Water Monitoring of Trace Metals and a Benthic Community Near the Palo Alto Regional Water Quality Control Plant in South San Francisco Bay, California: 2004

    Science.gov (United States)

    2005-01-01

    private contractor familiar with the taxonomy of San Francisco Bay invertebrates (Susan McCormick, Colfax, CA) (Appendix H). S. McCormick also...0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Unid. Isopoda 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.6667 1.15 0 0 0 0 Unid. Nudibranchia 0 0 0 0 0 0 0 0 0 0 0

  9. Reconstructing the natural hydrology of the San Francisco Bay-Delta watershed

    Directory of Open Access Journals (Sweden)

    P. Fox

    2015-04-01

    Full Text Available The San Francisco Estuary, composed of San Francisco Bay and the Sacramento–San Joaquin River Delta, is the largest estuary along the Pacific coast of the United States. The tributary watersheds of California's Central Valley are the principal sources of freshwater flow into the San Francisco Bay-Delta estuary. The Delta serves as one of the principal hubs of California's water system, which delivers 45% of the water used statewide to 25 million residents and 16 000 km2 of farmland. The development of California, from small-scale human settlements that co-existed with an environment rich in native vegetation to the eighth largest economy in the world was facilitated by reconfiguring the state's water resources to serve new uses: agriculture, industry, and a burgeoning population. The redistribution of water from native vegetation to other uses was accompanied by significant declines in native aquatic species that rely on the San Francisco Bay-Delta system. These declines have been attributed to a variety of causes, including reduction in the amount of freshwater reaching the San Francisco Bay-Delta watershed (Delta outflow; decreased sediment loads; increased nutrient loads; changes in nutrient stoichiometry; contaminants; introduced species; habitat degradation and loss; and shifts in the ocean–atmosphere system, among others. Among these stressors, only the volume of Delta outflow has been regulated in an effort to address the decline in aquatic species. As native species evolved under natural landscape conditions, prior to European settlement in the mid-18th century, we evaluated the impact of landscape changes on the amount of Delta outflow. We reconstructed the natural landscape and used water balances to estimate the long-term annual average Delta outflow that would have occurred under natural landscape conditions if the climate from 1922 to 2009 were to repeat. These outflows are referred to as "natural" Delta outflows and are the

  10. Carbon Sequestration in Mediterranean Tidal Wetlands: San Francisco Bay and the Ebro River Delta (Invited)

    Science.gov (United States)

    Callaway, J.; Fennessy, S.; Ibanez, C.

    2013-12-01

    Tidal wetlands accumulate soil carbon at relatively rapid rates, in large part because they build soil to counteract increases in sea-level rise. Because of the rapid rates of carbon sequestration, there is growing interest in evaluating carbon dynamics in tidal wetlands around the world; however, few measurements have been completed for mediterranean-type tidal wetlands, which tend to have relatively high levels of soil salinity, likely affecting both plant productivity and decomposition rates. We measured sediment accretion and carbon sequestration rates at tidal wetlands in two mediterranean regions: the San Francisco Bay Estuary (California, USA) and the Ebro River Delta (Catalonia, Spain). Sampling sites within each region represented a range of conditions in terms of soil salinity and plant communities, and these sites serve as potential analogs for long-term carbon sequestration in restored wetlands, which could receive credits under emerging policies for carbon management. Within San Francisco Bay, we collected six sediment cores per site at four salt marshes and two brackish tidal wetlands (two transects with three stations per transect at each site) in order to identify spatial variation both within and among wetlands in the Estuary. At the Ebro Delta, individual sediment cores were collected across 14 tidal wetland sites, including salt and brackish marshes from impounded areas, river mouths, coastal lagoon, and open bay settings. Cores were collected to 50 cm, and cores were dated using 137Cs and 210Pb. Most sites within San Francisco accreted 0.3-0.5 cm/yr, with slightly higher rates of accretion at low marsh stations; accretions rates based on 137Cs were slightly higher than those based on 210Pb, likely because of the shorter time frame covered by 137Cs dating. Accretion rates from the Ebro Delta sites were similar although more variable, with rates based on 137Cs ranging from 0.1 to 0.9 cm/yr and reflecting the wide range of conditions and management

  11. Stable lead isotopic analyses of historic and contemporary lead contamination of San Francisco Bay estuary

    Science.gov (United States)

    Ritson, P.I.; Bouse, R.M.; Flegal, A.R.; Luoma, S.N.

    1999-01-01

    Variations in stable lead isotopic composition (240Pb, 206Pb, 207Pb, 208Pb) in three sediment cores from the San Francisco Bay estuary document temporal changes in sources of lead during the past two centuries. Sediment, with lead from natural geologic sources, and relatively homogeneous lead isotopic compositions are overlain by sediments whose isotopic compositions indicate change in the sources of lead associated with anthropogenic modification of the estuary. The first perturbations of lead isotopic composition in the cores occur in the late 1800s concordant with the beginning of industrialization around the estuary. Large isotopic shifts, toward lower 206Pb/207Pb, occur after the turn of the century in both Richardson and San Pablo Bays. A similar relationship among lead isotopic compositions and lead concentrations in both Bays suggest contamination from the same source (a lead smelter). The uppermost sediments (post 1980) of all cores also have a relatively homogenous lead isotopic composition distinct from pre-anthropogenic and recent aerosol signatures. Lead isotopic compositions of leachates from fourteen surface sediments and five marsh samples from the estuary were also analyzed. These analyses suggest that the lead isotopic signature identified in the upper horizons of the cores is spatially homogeneous among recently deposited sediments throughout the estuary. Current aerosol lead isotopic compositions [Smith, D.R., Niemeyer, S., Flegal, A.R., 1992. Lead sources to California sea otters: industrial inputs circumvent natural lead biodepletion mechanisms. Environmental Research 57, 163-175] are distinct from the isotopic compositions of the surface sediments, suggesting that the major source of lead is cycling of historically contaminated sediments back through the water column. Both the upper core sediments and surface sediments apparently derive their lead predominantly from sources internal to the estuary. These results support the idea that

  12. Status and understanding of groundwater quality in the North San Francisco Bay groundwater basins, 2004

    Science.gov (United States)

    Kulongoski, Justin T.; Belitz, Kenneth; Landon, Matthew K.; Farrar, Christopher

    2010-01-01

    Groundwater quality in the approximately 1,000-square-mile (2,590-square-kilometer) North San Francisco Bay study unit was investigated as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study unit is located in northern California in Marin, Napa, and Sonoma Counties. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory. The GAMA North San Francisco Bay study was designed to provide a spatially unbiased assessment of untreated groundwater quality in the primary aquifer systems. The assessment is based on water-quality and ancillary data collected by the USGS from 89 wells in 2004 and water-quality data from the California Department of Public Health (CDPH) database. The primary aquifer systems (hereinafter referred to as primary aquifers) were defined by the depth interval of the wells listed in the CDPH database for the North San Francisco Bay study unit. The quality of groundwater in shallower or deeper water-bearing zones may differ from that in the primary aquifers; shallower groundwater may be more vulnerable to surficial contamination. The first component of this study, the status of the current quality of the groundwater resource, was assessed by using data from samples analyzed for volatile organic compounds (VOC), pesticides, and naturally occurring inorganic constituents, such as major ions and trace elements. This status assessment is intended to characterize the quality of groundwater resources within the primary aquifers of the North San Francisco Bay study unit, not the treated drinking water delivered to consumers by water purveyors. Relative-concentrations (sample concentration divided by the health- or aesthetic-based benchmark concentration) were used for evaluating groundwater quality for those constituents that have Federal and (or

  13. Organochlorine and PBDE concentrations in relation to cytochrome P450 activity in livers of Forster’s Terns (Sterna forsteri) and Caspian Terns (Hydroprogne caspia), in San Francisco Bay, California

    Science.gov (United States)

    Herring, Garth; Ackerman, Joshua T.; Eagles-Smith, Collin A.; Adelsbach, Terrence L.; Melancon, Mark J.; Stebbins, Katie R.; Hoffman, David J.

    2010-01-01

    We measured halogenated organic contaminants (HOCs) [polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and dichloro-diphenyl-trichloroethane (DDT)] and P450 [e.g., ethoxyresorufin-O-dealkylase (EROD)] stress in livers from Caspian tern (Hydroprogne caspia) adults and Forster’s tern (Sterna forsteri) adults and chicks in San Francisco Bay (SFB). Penta BDEs and tetra PBDEs composed 46–66% of ∑PBDE in terns. PCB homologues di, tri, penta, hexa, and hepta composed 93–95% of ∑PCBs and p′p-DDE composed 82–98% of all ∑DDTs. We found similar concentrations of ∑PBDEs [mean micrograms per gram wet weight (ww) ± standard error = 0.4 ± 0.1], ∑PCBs (5.9 ± 1.6), and ∑DDTs (0.6 ± 0.1) among species, sexes, and regions. However, concentrations were higher in Forster’s tern adults than chicks (∑PBDEs = 0.4 ± 0.1 and 0.1 ± 0.1; ∑PCBs = 7.08 ± 2.4 and 2.4 ± 1.4; ∑DDTs = 0.5 ± 0.1 and 0.1 ± 0.1; respectively), and there was a nonsignificant trend of elevated ∑PBDEs and ∑PCBs for adult Forster’s terns in the Central South Bay and Lower South Bay portions of SFB. Combined Forster’s tern and Caspian tern ∑DDTs bioaccumulated similarly to selenium, but not mercury, and there was a nonsignificant but positive trend for ∑PBDEs and ∑PCBs bioaccumulation with mercury. P450 protein activity was higher in adult Forster’s terns than Caspian terns, higher in Central South Bay than in Lower South Bay, and higher in adult Forster’s terns than in chicks.

  14. 75 FR 67620 - Temporary Security Zones; San Francisco Bay, Delta Ports, Monterey Bay and Humboldt Bay, CA

    Science.gov (United States)

    2010-11-03

    ... cruise ship, tanker or HIV that is underway, anchored, or moored within the San Francisco Bay and Delta..., within 500 yards ahead, astern and extending 500 yards along either side of any cruise ship, tanker or..., astern and extending 500 yards along either side of any cruise ship, tanker or HIV that is...

  15. Building a Habitat Conversion Model for San Francisco Bay Wetlands: A Multi-species Approach for Integrating GIS and Field Data

    Science.gov (United States)

    Diana Stralberg; Nils Warnock; Nadav Nur; Hildie Spautz; Gary W. Page

    2005-01-01

    More than 80 percent of San Francisco Bay's original tidal wetlands have been altered or displaced, reducing available habitat for a range of tidal marsh-dependent species, including the Federally listed California Clapper Rail (Rallus longirostris obsoletus) and three endemic Song Sparrow (Melospiza melodia) subspecies. In...

  16. Predictors of mercury spatial patterns in San Francisco Bay forage fish.

    Science.gov (United States)

    Greenfield, Ben K; Slotton, Darell G; Harrold, Katherine H

    2013-12-01

    Pollution reduction efforts should be targeted toward those sources that result in the highest bioaccumulation. For mercury (Hg) in estuaries and other complex water bodies, carefully designed biosentinel monitoring programs can help identify predictors of bioaccumulation and inform management priorities for source reduction. This study employed a probabilistic forage fish Hg survey with hypothesis testing in San Francisco Bay (California, USA). The goal was to determine what pollution sources, regions, and landscape features were associated with elevated Hg bioaccumulation. Across 99 sites, whole-body Hg concentrations in Mississippi silversides (Menidia audens) and topsmelt (Atherinops affinis) followed a broad spatial gradient, declining with distance from the Guadalupe River (Pearson's r = -0.69 and -0.42, respectively), which drains historic mining areas. Site landscape attributes and local Hg sources had subtle effects, which differed between fish species. Topsmelt Hg increased in embayment sites (i.e., enclosed sites including channels, creek mouths, marinas, and coves) and sites with historic Hg-contaminated sediment, suggesting an influence of legacy industrial and mining contamination. In 2008, Mississippi silverside Hg was reduced at sites draining wastewater-treatment plants. Fish Hg was not related to abundance of surrounding wetland cover but was elevated in some watersheds draining from historic Hg-mining operations. Results indicated both regional and site-specific influences for Hg bioaccumulation in San Francisco Bay, including legacy contamination and proximity to treated wastewater discharge. © 2013 SETAC.

  17. Rocks and geology in the San Francisco Bay region

    Science.gov (United States)

    Stoffer, Philip W.

    2002-01-01

    The landscape of the San Francisco Bay region is host to a greater variety of rocks than most other regions in the United States. This introductory guide provides illustrated descriptions of 46 common and important varieties of igneous, sedimentary, and metamorphic rock found in the region. Rock types are described in context of their identification qualities, how they form, and where they occur in the region. The guide also provides discussion about of regional geology, plate tectonics, the rock cycle, the significance of the selected rock types in relation to both earth history and the impact of mineral resources on the development in the region. Maps and text also provide information where rocks, fossils, and geologic features can be visited on public lands or in association with public displays in regional museums, park visitor centers, and other public facilities.

  18. San Francisco Bay Area Fault Observations Displayed in Google Earth

    Science.gov (United States)

    Lackey, H.; Hernandez, M.; Nayak, P.; Zapata, I.; Schumaker, D.

    2006-12-01

    According to the United States Geological Survey (USGS), the San Francisco Bay Area has a 62% probability of experiencing a major earthquake in the next 30 years. The Hayward fault and the San Andreas fault are the two main faults in the Bay Area that are capable of producing earthquakes of magnitude 6.7 or larger - a size that could profoundly affect many of the 7 million people who live in the Bay Area. The Hayward fault has a 27% probability of producing a major earthquake in next 30 years, and the San Andreas fault has a 21% probability. Our research group, which is part of the SF-ROCKS high school outreach program, studied the Hayward and San Andreas faults. The goal of our project was to observe these faults at various locations, measure the effects of creep, and to present the data in Google Earth, a freeware tool for the public to easily view and interact with these and other seismic-hazard data. We examined the Hayward and San Andreas faults (as mapped by USGS scientists) in Google Earth to identify various sites where we could possibly find evidence of fault creep. We next visited these sites in the field where we mapped the location using a hand- held Global Positioning System, identified and photographed fault evidence, and measured offset features with a ruler or tape measure. Fault evidence included en echelon shears in pavement, warped buildings, and offset features such as sidewalks. Fault creep offset measurements range from 1.5 19 cm. We also identified possible evidence of fault creep along the San Andreas fault in South San Francisco where it had not been previously described. In Google Earth, we plotted our field sites, linked photographs showing evidence of faulting, and included detailed captions to explain the photographs. We will design a webpage containing the data in a Keyhole Markup Language (KML) file format for display in Google Earth. Any interested person needs only to download the free version of Google Earth software and visit our

  19. Contours--Drakes Bay and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Drakes Bay and Vicinity map area, California. The vector data file is...

  20. Habitat--Drakes Bay and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the habitat map of the seafloor of the Drakes Bay and Vicinity map area, California. The vector data file is included in...

  1. Bathymetry--Drakes Bay and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetry and shaded-relief maps of Drakes Bay and Vicinity, California (raster data file is included in...

  2. Bathymetry--Offshore Half Moon Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetry and shaded-relief maps of the Offshore Half Moon Bay, California (raster data file is included in...

  3. Synthesis of long-term nickel monitoring in San Francisco Bay.

    Science.gov (United States)

    Yee, Don; Grieb, Thomas; Mills, William; Sedlak, Margaret

    2007-09-01

    The Regional Monitoring Program for Water Quality in the San Francisco Bay (RMP) has conducted annual monitoring of the San Francisco Estuary (estuary) since 1993. The RMP primarily monitors water, sediment, and bivalves, although short-term pilot and special studies on select topics are also conducted. The purpose of this article is to synthesize over 10 years of RMP nickel data and to illustrate how comprehensive monitoring data contribute to an understanding of contaminant fate. Nickel concentrations observed in water (43.7-233.7 nM) are largely a function of the geology of the watershed surrounding the estuary and inputs from wastewater treatment plants and urban runoff. The geologic formations supplying sediment to the estuary contain high concentrations of nickel (e.g., 1000-3300 microg/g). Much of the research to date on nickel speciation suggests that nickel complexes from wastewater treatment plants are not readily available for biological uptake [Bedsworth, W.W., Sedlak, D.L., 1999. Sources and environmental fate of strongly complexed nickel in estuarine waters: the role of ethylenediaminetetraacetate. Environ. Sci. Technol. 33, 926-931, Sedlak, D.L., Phinney, J.T., Bedsworth, W.W., 1997. Strongly complexed Cu and Ni in wastewater effluents and surface runoff. Environ. Sci. Technol. 31(10), 3010-3016, Donat, J.R., Lao, K.A., Bruland, K.W., 1994. Speciation of dissolved copper and nickel in South San Francisco Bay: a multi-method approach. Anal. Chim. Acta. 284, 547-571]. In addition, concentrations of nickel measured in biota by the RMP (0.905-113.0 microg/g dry weight in bivalve tissues) are well below recommended maximum tissue residue levels (220 microg/g wet weight, California state guidelines). Based on this information, regulators have reconsidered the water quality objectives developed for nickel.

  4. Microbial diversity and carbon cycling in San Francisco Bay wetlands

    Energy Technology Data Exchange (ETDEWEB)

    Theroux, Susanna [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Hartman, Wyatt [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; He, Shaomei [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Univ. of Wisconsin, Madison, WI (United States); Tringe, Susannah [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.

    2014-03-21

    Wetland restoration efforts in San Francisco Bay aim to rebuild habitat for endangered species and provide an effective carbon storage solution, reversing land subsidence caused by a century of industrial and agricultural development. However, the benefits of carbon sequestration may be negated by increased methane production in newly constructed wetlands, making these wetlands net greenhouse gas (GHG) sources to the atmosphere. We investigated the effects of wetland restoration on below-ground microbial communities responsible for GHG cycling in a suite of historic and restored wetlands in SF Bay. Using DNA and RNA sequencing, coupled with real-time GHG monitoring, we profiled the diversity and metabolic potential of wetland soil microbial communities. The wetland soils harbor diverse communities of bacteria and archaea whose membership varies with sampling location, proximity to plant roots and sampling depth. Our results also highlight the dramatic differences in GHG production between historic and restored wetlands and allow us to link microbial community composition and GHG cycling with key environmental variables including salinity, soil carbon and plant species.

  5. San Francisco Bay ecotone vegetation restoration & management : 2009-10 grant report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a report on vegetation restoration and management at Don Edwards San Francisco Bay National Wildlife Refuge. Restoring vegetation adjacent to the tidal...

  6. Annual Narrative Report : San Francisco Bay National Wildlife Refuge Complex : 1984

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report details the conditions and management of San Francisco Bay National Wildlife Refuge in 1984. The report begins with highlights from the...

  7. The Trail Inventory of Don Edwards San Francisco Bay NWR [Cycle 2

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The purpose of this report is to create a baseline inventory of all non-motorized trails on Don Edwards San Francisco Bay National Wildlife Refuge. Trails in this...

  8. San Francisco Bay ecotone vegetation restoration & management : 2008-09 grant report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a report on vegetation restoration and management at Don Edwards San Francisco Bay National Wildlife Refuge. Vegetation management is often straightforward:...

  9. San Francisco Bay Area Baseline Trash Loading Summary Results for all counties

    Data.gov (United States)

    U.S. Environmental Protection Agency — The San Francisco Bay Area stormwater permit sets trash control guidelines for discharges through the storm drain system. The permit covers Alameda, Contra Costa,...

  10. San Francisco Bay National Wildlife Refuge Complex : Annual Narrative Report : Calendar Year 1976

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report details the conditions and management of San Francisco Bay National Wildlife Refuge in 1976. The report begins with a general...

  11. San Francisco Bay NWR Complex : Annual Narrative Report : Calendar Year 1978

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report details the conditions and management of San Francisco Bay National Wildlife Refuge in 1978. The report begins with a general...

  12. Botulism protocols for the Don Edwards San Francisco Bay National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This plan gives a basic description of what avian botulism is and the locations on the Don Edwards San Francisco Bay National Wildlife Refuge where botulism...

  13. Public use at Don Edwards San Francisco Bay National Wildlife Refuge : Annual narrative 1997

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document contains the public use sections of the 1997 Annual Narrative Report for Don Edwards San Francisco Bay National Wildlife Refuge. Public use activities...

  14. Beneficial Uses of Dredged Material Case Study: San Francisco Bay Region

    Science.gov (United States)

    A major interagency, regional planning effort led to the development of the Long-Term Management Strategy and other planning programs in the San Francisco Bay area. These programs incorporate beneficial uses of dredged material into local projects.

  15. Narrative report: San Francisco Bay National Wildlife Refuge Complex: Fiscal year 1975

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for San Francisco Bay National Wildlife Refuge Complex outlines Refuge accomplishments during the 1975 fiscal year. Wildlife- including...

  16. Public use at San Francisco Bay National Wildlife Refuge : Annual Narrative 1993

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document contains the public use sections of the 1993 Annual Narrative Report for Don Edwards San Francisco Bay National Wildlife Refuge. Public use activities...

  17. Public use at Don Edwards San Francisco Bay National Wildlife Refuge : Annual narrative 1995

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document contains the public use sections of the 1995 Annual Narrative Report for Don Edwards San Francisco Bay National Wildlife Refuge. Public use activities...

  18. Public use at San Francisco Bay National Wildlife Refuge : Annual Narrative 1994

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document contains the public use sections of the 1994 Annual Narrative Report for Don Edwards San Francisco Bay National Wildlife Refuge. Public use activities...

  19. San Francisco Bay National Wildlife Refuge Complex : Annual Narrative Report : 1988

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report details the conditions and management of San Francisco Bay National Wildlife Refuge in 1988. The report begins with highlights from the...

  20. San Francisco Bay National Wildlife Refuge Complex : Annual Narrative Report : 1982

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report details the conditions and management of San Francisco Bay National Wildlife Refuge in 1982. The report begins with highlights from the...

  1. San Francisco Bay National Wildlife Refuge Complex : Annual Narrative Report : 1990

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report details the conditions and management of San Francisco Bay National Wildlife Refuge in 1990. The report begins with highlights from the...

  2. San Francisco Bay National Wildlife Refuge Complex : Annual Narrative Report : 1986

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report details the conditions and management of San Francisco Bay National Wildlife Refuge in 1986. The report begins with highlights from the...

  3. Don Edwards San Francisco Bay National Wildlife Refuge : Refuge Master Plan : 1974

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The San Francisco Bay National Wildlife Refuge Master Plan guides the longrange development of the Refuge by identifying and integrating appropriate habitats,...

  4. Physical and chemical properties of San Francisco Bay waters, 1969-1976 (NODC Accession 8400194)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — One magnetic tape containing the physical and chemical properties of San Francisco Bay waters was forwarded to NODC by Mr. Richard Smith of the U.S Geological Survey...

  5. Public use at Don Edwards San Francisco Bay National Wildlife Refuge : Annual narrative 1996

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document contains the public use sections of the 1996 Annual Narrative Report for Don Edwards San Francisco Bay National Wildlife Refuge. Public use activities...

  6. San Francisco Bay National Wildlife Refuge : Annual Narrative 1991 : Public use sections

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document contains the public use sections of the 1991 Annual Narrative Report for Don Edwards San Francisco Bay National Wildlife Refuge. Public use activities...

  7. Sources of mercury to San Francisco Bay surface sediment as revealed by mercury stable isotopes

    Science.gov (United States)

    Gehrke, Gretchen E.; Blum, Joel D.; Marvin-DePasquale, Mark

    2011-01-01

    Mercury (Hg) concentrations and isotopic compositions were examined in shallow-water surface sediment (0–2 cm) from San Francisco (SF) Bay to determine the extent to which historic Hg mining contributes to current Hg contamination in SF Bay, and to assess the use of Hg isotopes to trace sources of contamination in estuaries. Inter-tidal and wetland sediment had total Hg (HgT) concentrations ranging from 161 to 1529 ng/g with no simple gradients of spatial variation. In contrast, inter-tidal and wetland sediment displayed a geographic gradient of δ202Hg values, ranging from -0.30% in the southern-most part of SF Bay (draining the New Almaden Hg District) to -0.99% in the northern-most part of SF Bay near the Sacramento–San Joaquin River Delta. Similar to SF Bay inter-tidal sediment, surface sediment from the Alviso Slough channel draining into South SF Bay had a δ202Hg value of -0.29%, while surface sediment from the Cosumnes River and Sacramento–San Joaquin River Delta draining into north SF Bay had lower average δ202Hg values of -0.90% and -0.75%, respectively. This isotopic trend suggests that Hg-contaminated sediment from the New Almaden Hg District mixes with Hg-contaminated sediment from a low δ202Hg source north of SF Bay. Tailings and thermally decomposed ore (calcine) from the New Idria Hg mine in the California Coast Range had average δ202Hg values of -0.37 and +0.03%, respectively, showing that Hg calcination fractionates Hg isotopes resulting in Hg contamination from Hg(II) mine waste products with higher δ202Hg values than metallic Hg(0) produced from Hg mines. Thus, there is evidence for at least two distinct isotopic signals for Hg contamination in SF Bay: Hg associated with calcine waste materials at Hg mines in the Coast Range, such as New Almaden and New Idria; and Hg(0) produced from these mines and used in placer gold mines and/or in other industrial processes in the Sierra Nevada region and SF Bay area.

  8. Sources of mercury to San Francisco Bay surface sediment as revealed by mercury stable isotopes

    Science.gov (United States)

    Gehrke, Gretchen E.; Blum, Joel D.; Marvin-DiPasquale, Mark

    2011-02-01

    Mercury (Hg) concentrations and isotopic compositions were examined in shallow-water surface sediment (0-2 cm) from San Francisco (SF) Bay to determine the extent to which historic Hg mining contributes to current Hg contamination in SF Bay, and to assess the use of Hg isotopes to trace sources of contamination in estuaries. Inter-tidal and wetland sediment had total Hg (Hg T) concentrations ranging from 161 to 1529 ng/g with no simple gradients of spatial variation. In contrast, inter-tidal and wetland sediment displayed a geographic gradient of δ 202Hg values, ranging from -0.30‰ in the southern-most part of SF Bay (draining the New Almaden Hg District) to -0.99‰ in the northern-most part of SF Bay near the Sacramento-San Joaquin River Delta. Similar to SF Bay inter-tidal sediment, surface sediment from the Alviso Slough channel draining into South SF Bay had a δ 202Hg value of -0.29‰, while surface sediment from the Cosumnes River and Sacramento-San Joaquin River Delta draining into north SF Bay had lower average δ 202Hg values of -0.90‰ and -0.75‰, respectively. This isotopic trend suggests that Hg-contaminated sediment from the New Almaden Hg District mixes with Hg-contaminated sediment from a low δ 202Hg source north of SF Bay. Tailings and thermally decomposed ore (calcine) from the New Idria Hg mine in the California Coast Range had average δ 202Hg values of -0.37 and +0.03‰, respectively, showing that Hg calcination fractionates Hg isotopes resulting in Hg contamination from Hg(II) mine waste products with higher δ 202Hg values than metallic Hg(0) produced from Hg mines. Thus, there is evidence for at least two distinct isotopic signals for Hg contamination in SF Bay: Hg associated with calcine waste materials at Hg mines in the Coast Range, such as New Almaden and New Idria; and Hg(0) produced from these mines and used in placer gold mines and/or in other industrial processes in the Sierra Nevada region and SF Bay area.

  9. Tap water isotopes reveal the San Francisco Bay Area's plumbing and responses to a major drought

    Science.gov (United States)

    Tipple, B. J.; Jameel, M. Y.; Chau, T. H.; Mancuso, C. J.; Bowen, G. J.; Dufour, A.; Chesson, L. A.; Ehleringer, J. R.

    2016-12-01

    Water availability and sustainability in the Western United States is a major flashpoint among expanding communities, growing industries, and productive agricultural lands. This issue came to a head in 2015 in the State of California, when the State mandated a 25% reduction in urban water use following a multi-year drought that significantly depleted water resources. The demands for and challenges in supplying water are only expected to intensify as climate perturbations, such as the 2012-2015 California Drought, become more common. As a consequence, there is an increased need to understand linkages between population centers, water transport and usage, and the impacts of climate change on water resources and infrastructure. To better understand these relationships within a megalopolis in the Western United States, we collected and analyzed 723 tap waters from the San Francisco Bay Area during seven collection campaigns across 21 months during 2013-2015. San Francisco Bay Area was selected as it has well-known water management strategies and its water resources were dramatically affected by the 2012-2105 drought. Consistent with known water management strategies and previous reports of tap water isotope values, we found large spatiotemporal variations in the δ2H and δ18O values of tap waters, indicative of complex water transport systems and municipality-scale management decisions. We observed δ2H and δ18O values of tap water consistent with waters originating from snowmelt from the Sierra Nevada Mountains, local precipitation, ground water, and partially evaporated reservoir sources. A cluster analysis of measured tap water data grouped waters from 43 static sampling sites that were associated with specific water utility providers within the San Francisco Bay Area and known management practices. Water management responses to the drought, such as source switching, bringing in new sources, and conservation, could be observed within the isotope data from each of

  10. Lithostratigraphic, borehole-geophysical, hydrogeologic, and hydrochemical data from the East Bay Plain, Alameda County, California

    Science.gov (United States)

    Sneed, Michelle; Orlando, Patricia v.P.; Borchers, James W.; Everett, Rhett; Solt, Michael; McGann, Mary; Lowers, Heather; Mahan, Shannon

    2015-01-01

    The U.S. Geological Survey, in cooperation with the East Bay Municipal Utility District, carried out an investigation of aquifer-system deformation associated with groundwater-level changes at the Bayside Groundwater Project near the modern San Francisco Bay shore in San Lorenzo, California. As a part of the Bayside Groundwater Project, East Bay Municipal Utility District proposed an aquifer storage and recovery program for 1 million gallons of water per day. The potential for aquifer-system compaction and expansion, and related subsidence, uplift, or both, resulting from aquifer storage and recovery activities were investigated and monitored in the Bayside Groundwater Project. In addition, baseline analysis of groundwater and substrata properties were performed to assess the potential effect of such activities. Chemical and physical data, obtained from the subsurface at four sites on the east side of San Francisco Bay in the San Lorenzo and San Leandro areas of the East Bay Plain, Alameda County, California, were collected during the study. The results of the study were provided to the East Bay Municipal Utility District and other agencies to evaluate the chemical and mechanical responses of aquifers underlying the East Bay Plain to the future injection and recovery of imported water from the Sierra Nevada of California.

  11. Wave attenuation in the shallows of San Francisco Bay

    Science.gov (United States)

    Lacy, Jessica R.; MacVean, Lissa J.

    2016-01-01

    Waves propagating over broad, gently-sloped shallows decrease in height due to frictional dissipation at the bed. We quantified wave-height evolution across 7 km of mudflat in San Pablo Bay (northern San Francisco Bay), an environment where tidal mixing prevents the formation of fluid mud. Wave height was measured along a cross shore transect (elevation range−2mto+0.45mMLLW) in winter 2011 and summer 2012. Wave height decreased more than 50% across the transect. The exponential decay coefficient λ was inversely related to depth squared (λ=6×10−4h−2). The physical roughness length scale kb, estimated from near-bed turbulence measurements, was 3.5×10−3 m in winter and 1.1×10−2 m in summer. Estimated wave friction factor fw determined from wave-height data suggests that bottom friction dominates dissipation at high Rew but not at low Rew. Predictions of near-shore wave height based on offshore wave height and a rough formulation for fw were quite accurate, with errors about half as great as those based on the smooth formulation for fw. Researchers often assume that the wave boundary layer is smooth for settings with fine-grained sediments. At this site, use of a smooth fw results in an underestimate of wave shear stress by a factor of 2 for typical waves and as much as 5 for more energetic waves. It also inadequately captures the effectiveness of the mudflats in protecting the shoreline through wave attenuation.

  12. Spring climate and salinity in the San Francisco Bay Estuary

    Science.gov (United States)

    Cayan, Daniel R.; Peterson, David H.

    1993-01-01

    Salinity in the San Francisco Bay Estuary almost always experiences its yearly maximum during late summer, but climate variability produces marked interannual variations. The atmospheric circulation pattern impacts the estuary primarily through variations of runoff from rainfall and snowmelt from the Sierra Nevada and, secondarily, through variations in the near-surface salinity in the coastal ocean. While winter precipitation is the primary influence upon salinity in the estuary, spring climate variations also contribute importantly to salinity fluctuations. Spring atmospheric circulation influences both the magnitude and the timing of freshwater flows, through anomalies of precipitation and temperature. To help discriminate between the effects of these two influences, the record is divided into subsets according to whether spring conditions in the region are cool and wet, warm and wet, cool and dry, or warm and dry. Warm springs promote early snowmelt-driven flows, and cool springs result in delayed flows. In addition to effects of winter and spring climate variability operating on the watershed, there are more subtle effects that are transmitted into the estuary from the coastal ocean. These influences are most pronounced in cool and dry springs with high surface salinity (SS) in the coastal ocean versus cool and wet springs with low SS in the coastal ocean. A transect of SS records at stations from the mouth to the head of the bay suggests that the coastal ocean anomaly signal is attenuated from the mouth to the interior of the estuary. In contrast, a delayed, postsummer signal caused by winter and spring runoff variations from the upstream watershed are most pronounced at the head of the estuary and attenuate toward the mouth.

  13. SF Bayweb 2009: Planting the Seeds of an Observing System in the San Francisco Bay

    Science.gov (United States)

    2010-06-01

    UC Berkeley Berkeley, CA 94720 Toby Garfield SFSU Romberg Tiburon Center Tiburon, CA 94920 John Largier UC Davis / Bodega Marine Laboratory... Bodega Bay, Ca 94923 Abstract - A pilot project was recently completed in the San Francisco Bay from May 1-10, 2009, to test the use of advanced

  14. Handbook of Techniques and Guides for the Study of the San Francisco Bay-Delta-Estuary Complex, Part 6. Key to the Common Fishes of San Francisco Bay.

    Science.gov (United States)

    Sikora, Bob

    Project MER (Marine Ecology Research) is aimed at improving environmental education in the San Francisco Bay Area schools. As part of meeting this goal, it is hoped that students and teachers can see the results of their efforts being put to practical use. This guide is the sixth of a series produced to help students and teachers gather data…

  15. Near-field receiving water monitoring of trace metals and a benthic community near the Palo Alto Regional Water Quality Control Plant in South San Francisco Bay, California: 2013

    Science.gov (United States)

    Dyke, Jessica; Cain, Daniel J.; Thompson, Janet K.; Kleckner, Amy E.; Parcheso, Francis; Hornberger, Michelle I.; Luoma, Samuel N.

    2014-01-01

    Trace-metal concentrations in sediment and in the clam Macoma petalum (formerly reported as Macoma balthica), clam reproductive activity, and benthic macroinvertebrate community structure were investigated in a mudflat 1 kilometer south of the discharge of the Palo Alto Regional Water Quality Control Plant (PARWQCP) in South San Francisco Bay, Calif. This report includes the data collected by U.S. Geological Survey (USGS) scientists for the period January 2013 to December 2013. These data serve as the basis for the City of Palo Alto’s Near-Field Receiving Water Monitoring Program, initiated in 1994. Following significant reductions in the late 1980s, silver (Ag) and copper (Cu) concentrations in sediment and M. petalum appear to have stabilized. Data for other metals, including chromium (Cr), mercury (Hg), nickel (Ni), selenium (Se), and zinc (Zn), have been collected since 1994. Over this period, concentrations of these elements have remained relatively constant, aside from seasonal variation that is common to all elements. In 2013, concentrations of Ag and Cu in M. petalum varied seasonally in response to a combination of site-specific metal exposures and annual growth and reproduction, as reported previously. Seasonal patterns for other elements, including Cr, Ni, Zn, Hg, and Se, were generally similar in timing and magnitude as those for Ag and Cu. In M. petalum, all observed elements showed annual maxima in January–February and minima in April, except for Zn, which was lowest in December. In sediments, annual maxima also occurred in January–February, and minima were measured in June and September. In 2013, metal concentrations in both sediments and clam tissue were among the lowest concentrations on record. This record suggests that regional-scale factors now largely control sedimentary and bioavailable concentrations of Ag and Cu, as well as other elements of regulatory interest, at the Palo Alto site. Analyses of the benthic community structure of a

  16. Near-field receiving water monitoring of trace metals and a benthic community near the Palo Alto Regional Water Quality Control Plant in south San Francisco Bay, California, 2012

    Science.gov (United States)

    Dyke, Jessica; Thompson, Janet K.; Cain, Daniel J.; Kleckner, Amy E.; Parcheso, Francis; Luoma, Samuel N.; Hornberger, Michelle I.

    2013-01-01

    Trace-metal concentrations in sediment and in the clam Macoma petalum (formerly reported as Macoma balthica), clam reproductive activity, and benthic macroinvertebrate community structure were investigated in a mudflat 1 kilometer south of the discharge of the Palo Alto Regional Water Quality Control Plant (PARWQCP) in South San Francisco Bay, Calif. This report includes the data collected by U.S. Geological Survey (USGS) scientists for the period January to December 2012. These data serve as the basis for the City of Palo Alto’s Near-Field Receiving Water Monitoring Program, initiated in 1994. Following significant reductions in the late 1980s, silver (Ag) and copper (Cu) concentrations in sediment and in M. petalum appear to have stabilized. Data for other metals, including chromium (Cr), mercury (Hg), nickel (Ni), selenium (Se), and zinc (Zn), have been collected since 1994. Over this period, concentrations of these elements have remained relatively constant, aside from seasonal variation that is common to all elements. In 2012, concentrations of Ag and Cu in M. petalum varied seasonally in response to a combination of site-specific metal exposures and annual growth and reproduction, as reported for previous time periods. Seasonal patterns for other elements, including Cr, Ni, Zn, Hg, and Se were generally similar in timing and magnitude as those for Ag and Cu. In 2012, metal concentrations in both sediments and clam tissue were among the lowest concentrations on record. This record suggests that regional-scale factors now largely control sedimentary and bioavailable concentrations of Ag and Cu, as well as other elements of regulatory interest, at the Palo Alto site. Analyses of the benthic community structure of a mudflat in South San Francisco Bay over a 39-year period show that changes in the community have occurred concurrent with reduced concentrations of metals in the sediment and in the tissues of the biosentinel clam, M. petalum, from the same area

  17. Near-field receiving water monitoring of trace metals and a benthic community near the Palo Alto Regional Water Quality Control Plant in south San Francisco Bay, California; 2009

    Science.gov (United States)

    Dyke, Jessica; Parchaso, Janet K.; Thompson, Janet K.; Cain, Daniel J.; Luoma, Samuel N.; Hornberger, Michelle I.

    2010-01-01

    Results reported herein include trace element concentrations in sediment and in the clam Macoma petalum (formerly reported as Macoma balthica (Cohen and Carlton, 1995)), clam reproductive activity, and benthic macroinvertebrate community structure for a mudflat one kilometer south of the discharge of the Palo Alto Regional Water Quality Control Plant (PARWQCP) in South San Francisco Bay. This report includes data collected for the period January 2009 to December 2009 and extends a critical long-term biogeochemical record dating back to 1974. These data serve as the basis for the City of Palo Alto's Near-Field Receiving Water Monitoring Program, initiated in 1994. In 2009, metal concentrations in both sediments and clam tissue were among the lowest concentrations on record and consistent with results observed since 1991. Following significant reductions in the late 1980s, silver (Ag) and copper (Cu) concentrations appeared to have stabilized. Annual mean concentrations have fluctuated modestly (2-4 fold) in a nondirectional manner. Data for other metals, including chromium, mercury, nickel, selenium, vanadium, and zinc, have been collected since 1994. Over this period, concentrations of these elements, which more likely reflect regional inputs and systemwide processes, have remained relatively constant, aside from typical seasonal variation that is common to all elements. Within years, the winter months (January-March) generally exhibit maximum concentrations, with a decline to annual minima in spring through fall. Mercury (Hg) in sediments and M. petalum were comparable to concentrations observed in 2008 and were generally consistent with data from previous years. Selenium (Se) concentrations in sediment varied among years and showed no sustained temporal trend. In 2009, sedimentary Se concentrations declined from the record high concentrations observed in 2008 to concentrations that were among the lowest on record. Selenium in M. petalum was unchanged from 2008

  18. California State Waters Map Series: offshore of San Francisco, California

    Science.gov (United States)

    Cochrane, Guy R.; Johnson, Samuel Y.; Dartnell, Peter; Greene, H. Gary; Erdey, Mercedes D.; Golden, Nadine E.; Hartwell, Stephen R.; Endris, Charles A.; Manson, Michael W.; Sliter, Ray W.; Kvitek, Rikk G.; Watt, Janet Tilden; Ross, Stephanie L.; Bruns, Terry R.; Cochrane, Guy R.; Cochran, Susan A.

    2015-01-01

    In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology.

  19. Benthic flux of dissolved nickel into the water column of south San Francisco Bay

    Science.gov (United States)

    Topping, B.R.; Kuwabara, J.S.; Parcheso, Francis; Hager, S.W.; Arnsberg, A.J.; Murphy, Fred

    2001-01-01

    Field and laboratory studies were conducted between April, 1998 and May, 1999 to provide the first direct measurements of the benthic flux of dissolved (0.2-micron filtered) nickel between the bottom sediment and water column at three sites in the southern component of San Francisco Bay (South Bay), California. Dissolved nickel and predominant ligands (represented by dissolved organic carbon, and sulfides) were the solutes of primary interest, although a variety of ancillary measurements were also performed to provide a framework for interpretation. Results described herein integrate information needs identified by the State Water Resources Control Board and local stakeholders with fundamental research associated with the U.S. Geological Survey Toxic Substances Hydrology Program. Dissolved-Ni concentrations in the bottom water over the three sampling dates ranged from 34 to 43 nanomoles per liter. Dissolved-macronutrient concentrations in the bottom water were consistently higher (frequently by orders of magnitude) than surface-water determinations reported for similar times and locations (Regional Monitoring Program, 2001). This is consistent with measured positive benthic fluxes for the macronutrients. Benthic-flux estimates for dissolved nickel from core-incubations, when areally averaged over the South Bay, were significant (that is, of equivalent or greater order of magnitude) relative to previously reported freshwater point and non-point sources. This observation is consistent with previous determinations for other metals, and with the potential remobilization of sediment-associated metals that have been ubiquitously distributed in the South Bay. Similar to dissolved-nickel results, benthic flux of macronutrients was also consistently significant relative to surface-water inputs. These results add to a growing body of knowledge that strongly suggests a need to consider contaminant transport across the sediment-water interface when establishing future

  20. Concentrations and time trends of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in aquatic bird eggs from San Francisco Bay, CA 2000-2003

    Science.gov (United States)

    She, J.; Holden, A.; Adelsbach, T.L.; Tanner, M.; Schwarzbach, S.E.; Yee, J.L.; Hooper, K.

    2008-01-01

    Concentrations of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in 169 avian eggs. We analyzed randomly collected eggs of two species of piscivorous birds: Caspian tern (Sterna caspia) (n = 78) and Forster's tern (Sterna forsteri) (n = 76). We also analyzed fail-to-hatch eggs from two species protected under the Federal Endangered Species Act of 1973, that breed in the San Francisco Bay region: the piscivorous California Least tern (Sterna antillarum brownii) (n = 11) and the omnivorous California Clapper rail (Rallus longirostris obsoletus) (n = 4). San Francisco Bay eggs were collected annually for four years (2000-2003), and additional 20 eggs were collected and analyzed from Gray's Harbor, Washington in 2001. Geometric mean PBDE concentrations did not significantly differ in the three tern species, but concentrations in eggs from the fail to hatch California Clapper rail eggs were significantly lower than those found in the randomly collected tern eggs. Median concentrations of ???PBDEs in Caspian tern eggs for 2000-2003 were 2410, 4730, 3720 and 2880 ng/g lipid weight (lw), respectively, in Forster's terns 1820, 4380, 5460 and 3600 ng/g lw, respectively, and in California Least terns for 2001 and 2002 were 5060 and 5170 ng/g lw, respectively. In contrast, median ???PBDEs concentration in California Clapper rail eggs for 2001 was 379 ng/g lw. Five PBDEs were the major congeners found and decreased in the order BDE-47, -99, -100, -153, and -154. BDE-32, -28, -71, -66, -85, -183 were less prevalent, minor congeners, as was BDE-209, which was measured in a subset of samples. PBDE concentrations in bird eggs from San Francisco Bay were site related. There was no significant difference in PBDE concentrations in Caspian tern eggs from San Francisco Bay and Gray's Harbor, WA. Average PBDE concentrations in eggs did not significantly increase over the period 2000-2003. ?? 2008 Elsevier Ltd. All rights reserved.

  1. Three-dimensional seismic velocity structure of the San Francisco Bay area

    Science.gov (United States)

    Hole, J. A.; Brocher, T. M.; Klemperer, S. L.; Parsons, T.; Benz, H. M.; Furlong, K. P.

    2000-06-01

    Seismic travel times from the northern California earthquake catalogue and from the 1991 Bay Area Seismic Imaging Experiment (BASIX) refraction survey were used to obtain a three-dimensional model of the seismic velocity structure of the San Francisco Bay area. Nonlinear tomography was used to simultaneously invert for both velocity and hypocenters. The new hypocenter inversion algorithm uses finite difference travel times and is an extension of an existing velocity tomography algorithm. Numerous inversions were performed with different parameters to test the reliability of the resulting velocity model. Most hypocenters were relocated 12 km under the Sacramento River Delta, 6 km beneath Livermore Valley, 5 km beneath the Santa Clara Valley, and 4 km beneath eastern San Pablo Bay. The Great Valley Sequence east of San Francisco Bay is 4-6 km thick. A relatively high velocity body exists in the upper 10 km beneath the Sonoma volcanic field, but no evidence for a large intrusion or magma chamber exists in the crust under The Geysers or the Clear Lake volcanic center. Lateral velocity contrasts indicate that the major strike-slip faults extend sub vertically beneath their surface locations through most of the crust. Strong lateral velocity contrasts of 0.3-0.6 km/s are observed across the San Andreas Fault in the middle crust and across the Hayward, Rogers Creek, Calaveras, and Greenville Faults at shallow depth. Weaker velocity contrasts (0.1-0.3 km/s) exist across the San Andreas, Hayward, and Rogers Creek Faults at all other depths. Low spatial resolution evidence in the lower crust suggests that the top of high-velocity mafic rocks gets deeper from west to east and may be offset under the major faults. The data suggest that the major strike-slip faults extend sub vertically through the middle and perhaps the lower crust and juxtapose differing lithology due to accumulated strike-slip motion. The extent and physical properties of the major geologic units as

  2. A Creek to Bay Biological Assessment in Oakland, California

    Science.gov (United States)

    Ahumada, E.; Ramirez, N.; Lopez, A.; Avila, M.; Ramirez, J.; Arroyo, D.; Bracho, H.; Casanova, A.; Pierson, E.

    2011-12-01

    In 2007, the Surface Water Ambient Monitoring Program (SWAMP) assessed the impact of trash on water quality in the Peralta Creek which is located in the Fruitvale district of Oakland, CA. This 2011 follow-up study will take further steps in evaluating the physical and biological impacts of pollution and human development on Peralta Creek and in the San Leandro Bay, where the Creek empties into the larger San Francisco Bay estuary. This study will utilize two forms of biological assessment in order to determine the level of water quality and ecosystem health of Peralta Creek and San Leandro Bay in Oakland, California. A Rapid Bioassesment Protocal (RBP) will be used as the method of biological assessment for Peralta Creek. RBP uses a biotic index of benthic macroinvertebrates to provide a measure of a water body's health. Larval trematodes found in two mud snails (Ilynassa obsoleta and Cerithidea californica) will be used to evaluate the health of the San Leandro Bay. Due to the complex life cycle of trematodes, the measure of trematode diversity and richness in host species serves as an indicator of estuarine health (Huspeni 2005). We have completed the assessment of one section of Peralta Creek, located at 2465 34th Avenue, Oakland, CA 94601. Abundance results indicate a moderately healthy creek because there were high levels of pollution tolerant benthic macroinvertebrates. The tolerant group of benthic macroinvertebrates includes such organisms as flatworms, leeches, and scuds. This is possibly due to this section of the creek being pumped up to the surface from culverts impacting the macroinvertebrate's life cycle. Another contributing factor to creek health is the amount of organic debris found in the creek, which inhibits the flow and oxygenation of the water, allowing for more pollution tolerant aquatic insects to persist. Further investigation is being conducted to fully assess the Peralta Creek watershed; from the preliminary results one can surmise that

  3. 77 FR 59749 - Special Local Regulations for Marine Events; San Francisco Bay Navy Fleet Week Parade of Ships...

    Science.gov (United States)

    2012-10-01

    ... Fleet Week Parade of Ships and Blue Angels Demonstration, San Francisco Bay, CA AGENCY: Coast Guard, DHS... sponsored Fleet Week Parade of Navy Ships, Blue Angels Flight Demonstrations, Ship Tours, and America's Cup... special local regulation for the annual San Francisco Bay Navy Fleet Week Parade of Ships and Blue...

  4. Time scales of change in the San Francisco Bay benthos

    Science.gov (United States)

    Nichols, F.H.; Thompson, J.K.

    1985-01-01

    Results from multi-year investigations in the San Francisco Bay estuary show that large abundance fluctuations within benthic macroinvertebrate populations reflect both (1) within-year periodicity of reproduction, recruitment, and mortality that is not necessarily coincident with seasonal changes of the environment (e.g., the annual temperature cycle), and (2) aperiodic density changes (often larger than within-year fluctuations) following random perturbations of the environment. Density peaks of the small, short-lived estuarine invertebrates that comprise the vast majority of individuals in the bay's relatively homogeneous benthic community normally occur between spring and autumn depending on the species, in large part a reflection of reproductive periodicity. However, because mild winters permit reproductive activity in some of the common species throughout much of the year, other factors are important to within-year density fluctuations in the community. Seasonally predictable changes in freshwater inflow, wind and tidal mixing, microalgal biomass, and sediment erosion/deposition patterns all contribute to observed seasonal changes in abundance. For example, the commonly observed decline in abundance during winter reflects both short-lived species that die after reproducing and the stress of winter conditions (e.g., inundation by less saline, sediment-laden water and the decline in both planktonic and benthic algal biomass - a direct source of food for the shallow-water benthos). On the other hand, data from several studies suggest that observed 'recruitment' and 'mortality' may in fact be the migration of juveniles and adults to and from study sites. For example, the common amphipod Ampelisca abdita apparently moves from shallow to deep water, or from up-estuary to down-estuary locations, coincident with periods of high river runoff in winter. Growth of individuals within the few studied species populations is also highly seasonal, and appears to be coincident

  5. Climate variability in an estuary: Effects of riverflow on San Francisco Bay

    Science.gov (United States)

    Peterson, David H.; Cayan, Daniel R.; Festa, John F.; Nichols, Frederic H.; Walters, Roy A.; Slack, James V.; Hager, Stephen E.; Schemel, Laurence E.; Peterson, David H.

    1989-01-01

    A simple conceptual model of estuarine variability in the context of climate forcing has been formulated using up to 65 years of estimated mean-monthly delta flow, the cumulative freshwater flow to San Francisco Bay from the Sacramento-San Joaquin River, and salinity observations near the mouth, head, mid-estuary, and coastal ocean. Variations in delta flow, the principal source of variability in the bay, originate from anomalous changes in northern and central California streamflow, much of which is linked to anomalous winter sea level pressure (“CPA”) in the eastern Pacific. In years when CPA is strongly negative, precipitation in the watershed is heavy, delta flow is high, and the bay's salinity is low; similarly, when CPA is strongly positive, precipitation is light, delta flow is low, and the bay's salinity is high. Thus the pattern of temporal variability in atmospheric pressure anomalies is reflected in the streamflow, then in delta flow, then in estuarine variability. Estuarine salinity can be characterized by river to ocean patterns in annual cycles of salinity in relation to delta flow. Salinity (total dissolved solids) data from the relatively pristine mountain streams of the Sierra Nevada show that for a given flow, one observes higher salinities during the rise in winter flow than on the decline. Salinity at locations throughout San Francisco Bay estuary are also higher during the rise in winter flow than the decline (because it takes a finite time for salinity to fully respond to changes in freshwater flow). In the coastal ocean, however, the annual pattern of sea surface salinity is reversed: lower salinities during the rise in winter flow than on the decline due to effects associated with spring upwelling. Delta flow in spring masks these effects of coastal upwelling on estuarine salinity, including near the mouth of the estuary and, in fact, explains in a statistical sense 86 percent of the variance in salinity at the mouth of the estuary. Some

  6. Reducing methylmercury accumulation in the food webs of San Francisco Bay and its local watersheds

    Energy Technology Data Exchange (ETDEWEB)

    Davis, J.A., E-mail: jay@sfei.org [San Francisco Estuary Institute, 4911 Central Avenue, Richmond, CA 94804 (United States); Looker, R.E. [San Francisco Bay Regional Water Quality Control Board, 1515 Clay Street, Suite 1400, Oakland, CA 94612 (United States); Yee, D. [San Francisco Estuary Institute, 4911 Central Avenue, Richmond, CA 94804 (United States); Marvin-Di Pasquale, M. [U.S. Geological Survey, Water Resources Division/MS 480, 345 Middlefield Road, Menlo Park, CA 94025 (United States); Grenier, J.L. [San Francisco Estuary Institute, 4911 Central Avenue, Richmond, CA 94804 (United States); Austin, C.M. [San Francisco Bay Regional Water Quality Control Board, 1515 Clay Street, Suite 1400, Oakland, CA 94612 (United States); McKee, L.J.; Greenfield, B.K. [San Francisco Estuary Institute, 4911 Central Avenue, Richmond, CA 94804 (United States); Brodberg, R. [California Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, 1001 I Street, Sacramento, CA 95812 (United States); Blum, J.D. [Department of Geological Sciences, University of Michigan, 1100 North University Avenue, Ann Arbor, MI 48109 (United States)

    2012-11-15

    San Francisco Bay (California, USA) and its local watersheds present an interesting case study in estuarine mercury (Hg) contamination. This review focuses on the most promising avenues for attempting to reduce methylmercury (MeHg) contamination in Bay Area aquatic food webs and identifying the scientific information that is most urgently needed to support these efforts. Concern for human exposure to MeHg in the region has led to advisories for consumption of sport fish. Striped bass from the Bay have the highest average Hg concentration measured for this species in USA estuaries, and this degree of contamination has been constant for the past 40 years. Similarly, largemouth bass in some Bay Area reservoirs have some of the highest Hg concentrations observed in the entire US. Bay Area wildlife, particularly birds, face potential impacts to reproduction based on Hg concentrations in the tissues of several Bay species. Source control of Hg is one of the primary possible approaches for reducing MeHg accumulation in Bay Area aquatic food webs. Recent findings (particularly Hg isotope measurements) indicate that the decades-long residence time of particle-associated Hg in the Bay is sufficient to allow significant conversion of even the insoluble forms of Hg into MeHg. Past inputs have been thoroughly mixed throughout this shallow and dynamic estuary. The large pool of Hg already present in the ecosystem dominates the fraction converted to MeHg and accumulating in the food web. Consequently, decreasing external Hg inputs can be expected to reduce MeHg in the food web, but it will likely take many decades to centuries before those reductions are achieved. Extensive efforts to reduce loads from the largest Hg mining source (the historic New Almaden mining district) are underway. Hg is spread widely across the urban landscape, but there are a number of key sources, source areas, and pathways that provide opportunities to capture larger quantities of Hg and reduce loads

  7. Spatial and temporal variations in silver contamination and toxicity in San Francisco Bay.

    Science.gov (United States)

    Flegal, A R; Brown, C L; Squire, S; Ross, J R M; Scelfo, G M; Hibdon, S

    2007-09-01

    Although San Francisco Bay has a "Golden Gate", it may be argued that it is the "Silver Estuary". For at one time the Bay was reported to have the highest levels of silver in its sediments and biota, along with the only accurately measured values of silver in solution, of any estuarine system. Since then others have argued that silver contamination is higher elsewhere (e.g., New York Bight, Florida Bay, Galveston Bay) in a peculiar form of pollution machismo, while silver contamination has measurably declined in sediments, biota, and surface waters of the Bay over the past two to three decades. Documentation of those systemic temporal declines has been possible because of long-term, ongoing monitoring programs, using rigorous trace metal clean sampling and analytical techniques, of the United States Geological Survey and San Francisco Bay Regional Monitoring Program that are summarized in this report. However, recent toxicity studies with macro-invertebrates in the Bay have indicated that silver may still be adversely affecting the health of the estuarine system, and other studies have indicated that silver concentrations in the Bay may be increasing due to new industrial inputs and/or the diagenetic remobilization of silver from historically contaminated sediments being re-exposed to overlying surface waters and benthos. Consequently, the Bay may not be ready to relinquish its title as the "Silver Estuary".

  8. Spatial and temporal variations in silver contamination and toxicity in San Francisco Bay

    Science.gov (United States)

    Flegal, A.R.; Brown, C.L.; Squire, S.; Ross, J.R.M.; Scelfo, G.M.; Hibdon, S.

    2007-01-01

    Although San Francisco Bay has a "Golden Gate", it may be argued that it is the "Silver Estuary". For at one time the Bay was reported to have the highest levels of silver in its sediments and biota, along with the only accurately measured values of silver in solution, of any estuarine system. Since then others have argued that silver contamination is higher elsewhere (e.g., New York Bight, Florida Bay, Galveston Bay) in a peculiar form of pollution machismo, while silver contamination has measurably declined in sediments, biota, and surface waters of the Bay over the past two to three decades. Documentation of those systemic temporal declines has been possible because of long-term, ongoing monitoring programs, using rigorous trace metal clean sampling and analytical techniques, of the United States Geological Survey and San Francisco Bay Regional Monitoring Program that are summarized in this report. However, recent toxicity studies with macro-invertebrates in the Bay have indicated that silver may still be adversely affecting the health of the estuarine system, and other studies have indicated that silver concentrations in the Bay may be increasing due to new industrial inputs and/or the diagenetic remobilization of silver from historically contaminated sediments being re-exposed to overlying surface waters and benthos. Consequently, the Bay may not be ready to relinquish its title as the "Silver Estuary". ?? 2007 Elsevier Inc. All rights reserved.

  9. External impacts of an intraurban air transportation system in the San Francisco Bay area

    Science.gov (United States)

    Lu, J. Y.; Gebman, J. R.; Kirkwood, T. F.; Mcclure, P. T.; Stucker, J. P.

    1972-01-01

    The effects are studied of an intraurban V/STOL commuter system on the economic, social, and physical environment of the San Francisco Bay Area. The Bay Area was chosen mainly for a case study; the real intent of the analysis is to develop methods by which the effects of such a system could be evaluated for any community. Aspects of the community life affected include: income and employment, benefits and costs, noise, air pollution, and road congestion.

  10. Geology and geomorphology--Offshore of San Francisco Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the geologic and geomorphic map of the Offshore of San Francisco map area, California. The polygon shapefile is included in...

  11. Geology and geomorphology--Offshore of San Francisco Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the geologic and geomorphic map of the Offshore of San Francisco map area, California. The polygon shapefile is included in...

  12. Survival of postfledging Forster's terns in relation to mercury exposure in San Francisco Bay

    Science.gov (United States)

    Ackerman, J.T.; Eagles-Smith, C. A.; Takekawa, J.Y.; Iverson, S.A.

    2008-01-01

    We examined factors influencing mercury concentrations in 90 fledgling Forster's terns (Sterna forsteri) and evaluated whether mercury influenced postfledging survival in San Francisco Bay, California. Mercury concentrations (??SE) in chicks 21-29 days old (just before fledging) were 0.33 ?? 0.01 ??g g-1 ww for blood and 6.44 ?? 0.28 ??g g -1 fw for breast feathers. Colony site had an overriding influence on fledgling contamination, however hatching date and age also affected blood, but not feather, mercury concentrations. Blood mercury concentrations decreased by 28% during the 50-day hatching period and increased with chick age by 30% during the last week prior to fledging. Using radio-telemetry, we calculated that cumulative survival during the 35-day postfledging time period was 0.81 ?? 0.09 (SE). Postfledging survival rates increased with size-adjusted mass, and cumulative survival probability was 61% lower for terns with the lowest, compared to the highest, observed masses. Conversely, survival was not influenced by blood mercury concentration, time since fledging, sex, or hatch date. Mercury concentrations in breast feathers of fledglings found dead at nesting colonies also were no different than those in live chicks. Our results indicate that colony site, hatching date, and age influenced mercury concentrations in fledgling Forster's terns, but that mercury did not influence postfledging survival. ?? 2008 Springer Science+Business Media, LLC.

  13. Acquired Color Vision Defects and Hexane Exposure: A Study of San Francisco Bay Area Automotive Mechanics.

    Science.gov (United States)

    Beckman, Stella; Eisen, Ellen A; Bates, Michael N; Liu, Sa; Haegerstrom-Portnoy, Gunilla; Hammond, S Katharine

    2016-06-01

    Occupational exposure to solvents, including n-hexane, has been associated with acquired color vision defects. Blue-yellow defects are most common and may be due to neurotoxicity or retinal damage. Acetone may potentiate the neurotoxicity of n-hexane. We present results on nonhexane solvent and hexane exposure and color vision from a cross-sectional study of 835 automotive repair workers in the San Francisco Bay Area, California (2007-2013). Cumulative exposure was estimated from self-reported work history, and color vision was assessed using the Lanthony desaturated D-15 panel test. Log-binomial regression was used to estimate prevalence ratios for color vision defects. Acquired color vision defects were present in 29% of participants, of which 70% were blue-yellow. Elevated prevalence ratios were found for nonhexane solvent exposure, with a maximum of 1.31 (95% confidence interval (CI): 0.86, 2.00) for blue-yellow. Among participants aged ≤50 years, the prevalence ratio for blue-yellow defects was 2.17 (95% CI: 1.03, 4.56) in the highest quartile of nonhexane solvent exposure and 1.62 (95% CI: 0.97, 2.72) in the highest category of exposure to hexane with acetone coexposure. Cumulative exposures to hexane and nonhexane solvents in the highest exposure categories were associated with elevated prevalence ratios for color vision defects in younger participants.

  14. Delineating incised stream sediment sources within a San Francisco Bay tributary basin

    Science.gov (United States)

    Bigelow, Paul; Benda, Lee; Pearce, Sarah

    2016-07-01

    Erosion and sedimentation pose ubiquitous problems for land and watershed managers, requiring delineation of sediment sources and sinks across landscapes. However, the technical complexity of many spatially explicit erosion models precludes their use by practitioners. To address this critical gap, we demonstrate a contemporary use of applied geomorphometry through a straightforward GIS analysis of sediment sources in the San Francisco Bay Area in California, USA, designed to support erosion reduction strategies. Using 2 m lidar digital elevation models, we delineated the entire river network in the Arroyo Mocho watershed (573 km2) at the scale of ˜ 30 m segments and identified incised landforms using a combination of hillslope gradient and planform curvature. Chronic erosion to the channel network was estimated based on these topographic attributes and the size of vegetation, and calibrated to sediment gage data, providing a spatially explicit estimate of sediment yield from incised channels across the basin. Rates of erosion were summarized downstream through the channel network, revealing patterns of sediment supply at the reach scale. Erosion and sediment supply were also aggregated to subbasins, allowing comparative analyses at the scale of tributaries. The erosion patterns delineated using this approach provide land use planners with a robust framework to design erosion reduction strategies. More broadly, the study demonstrates a modern analysis of important geomorphic processes affected by land use that is easily applied by agencies to solve common problems in watersheds, improving the integration between science and environmental management.

  15. CONSTANCY OF THE RELATION BETWEEN FLOC SIZE AND DENSITY IN SAN FRANCISCO BAY

    Science.gov (United States)

    Ganju, N.K., D.H. Schoellhamer, M.C. Murrell, J.W. Gartner and S.A. Wright. In press. Constancy of the Relation Between Floc Size and Density in San Francisco Bay. In: INTERCOH 2003: Proceedings of the 7th International Conference on Nearshore and Estuarine Cohesive Sediment Tran...

  16. EPA Administrator and San Francisco Bay Area government agencies celebrate nations largest solar energy partnership

    Science.gov (United States)

    SAN FRANCISCO - Today, U.S. EPA Administrator Gina McCarthy joined Bay Area agencies to celebrate the Regional Renewable Energy Procurement Project (R-REP), the nation's largest solar energy government collaboration and the launch of the Federal Agg

  17. Sediment Deposition, Erosion, and Bathymetric Change in Central San Francisco Bay: 1855-1979

    Science.gov (United States)

    Fregoso, Theresa A.; Foxgrover, Amy C.; Jaffe, Bruce E.

    2008-01-01

    Central San Francisco Bay is the hub of a dynamic estuarine system connecting the San Joaquin and Sacramento River Deltas, Suisun Bay, and San Pablo Bay to the Pacific Ocean and South San Francisco Bay. To understand the role that Central San Francisco Bay plays in sediment transport throughout the system, it is necessary to first determine historical changes in patterns of sediment deposition and erosion from both natural and anthropogenic forces. The first extensive hydrographic survey of Central San Francisco Bay was conducted in 1853 by the National Ocean Service (NOS) (formerly the United States Coast and Geodetic Survey (USCGS)). From 1894 to 1979, four additional surveys, composed of a total of approximately 700,000 bathymetric soundings, were collected within Central San Francisco Bay. Converting these soundings into accurate bathymetric models involved many steps. The soundings were either hand digitized directly from the original USCGS and NOS hydrographic sheets (H-sheets) or obtained digitally from the National Geophysical Data Center's (NGDC) Geophysical Data System (GEODAS) (National Geophysical Data Center, 1996). Soundings were supplemented with contours that were either taken directly from the H-sheets or added in by hand. Shorelines and marsh areas were obtained from topographic sheets. The digitized soundings, depth contours, shorelines, and marsh areas were entered into a geographic information system (GIS) and georeferenced to a common horizontal datum. Using surface modeling software, bathymetric grids with a horizontal resolution of 25 m were developed for each of the five hydrographic surveys. Before analyses of sediment deposition and erosion were conducted, interpolation bias was removed and all of the grids were converted to a common vertical datum. These bathymetric grids were then used to develop bathymetric change maps for subsequent survey periods and to determine long-term changes in deposition and erosion by calculating volumes and

  18. Earthquake probabilities in the San Francisco Bay Region: 2000 to 2030 - a summary of findings

    Science.gov (United States)

    ,

    1999-01-01

    The San Francisco Bay region sits astride a dangerous “earthquake machine,” the tectonic boundary between the Pacific and North American Plates. The region has experienced major and destructive earthquakes in 1838, 1868, 1906, and 1989, and future large earthquakes are a certainty. The ability to prepare for large earthquakes is critical to saving lives and reducing damage to property and infrastructure. An increased understanding of the timing, size, location, and effects of these likely earthquakes is a necessary component in any effective program of preparedness. This study reports on the probabilities of occurrence of major earthquakes in the San Francisco Bay region (SFBR) for the three decades 2000 to 2030. The SFBR extends from Healdsberg on the northwest to Salinas on the southeast and encloses the entire metropolitan area, including its most rapidly expanding urban and suburban areas. In this study a “major” earthquake is defined as one with M≥6.7 (where M is moment magnitude). As experience from the Northridge, California (M6.7, 1994) and Kobe, Japan (M6.9, 1995) earthquakes has shown us, earthquakes of this size can have a disastrous impact on the social and economic fabric of densely urbanized areas. To reevaluate the probability of large earthquakes striking the SFBR, the U.S. Geological Survey solicited data, interpretations, and analyses from dozens of scientists representing a wide crosssection of the Earth-science community (Appendix A). The primary approach of this new Working Group (WG99) was to develop a comprehensive, regional model for the long-term occurrence of earthquakes, founded on geologic and geophysical observations and constrained by plate tectonics. The model considers a broad range of observations and their possible interpretations. Using this model, we estimate the rates of occurrence of earthquakes and 30-year earthquake probabilities. Our study considers a range of magnitudes for earthquakes on the major faults in the

  19. Late Quaternary relative sea level in Southern California and Monterey Bay

    Science.gov (United States)

    Reynolds, Laura C.; Simms, Alexander R.

    2015-10-01

    Few records of late Quaternary relative sea level (RSL) are available for the Pacific coast of North America south of San Francisco Bay, a region where RSL data would be particularly useful for constraining vertical rates of tectonic motion. This paper provides the first regional, uplift-corrected late Quaternary RSL history for southern California derived from a compilation of 132 previously published and unpublished radiocarbon ages from nearshore, estuarine, and freshwater deposits in sediment cores from coastal southern California. We also provide a local, uplift-corrected RSL history for Monterey Bay, central California, generated from 48 radiocarbon ages from Elkhorn Slough and surrounding environments. Our resulting compilations show rapid sea-level rise from 15 ka which begins to decelerate to present mean sea level (PMSL) between 6 and 8 ka. Late Holocene (Bay in central California. Both rates of late Holocene RSL rise calculated are lower than recent RSL rates from southern California (˜1.61 ± 0.34 to 2.4 ± 1.04 mm a-1) and Monterey Bay (1.49 ± 0.95 mm a-1), derived from uplift-corrected, 20th century tide gauge data. This new RSL data fills geographical gaps in relative sea-level histories, as well as provides important datums for local tectonic processes.

  20. Humboldt Bay Benthic Habitats 2009 Aquatic Setting

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Humboldt Bay is the largest estuary in California north of San Francisco Bay and represents a significant resource for the north coast region. Beginning in 2007 the...

  1. 78 FR 57482 - Safety Zone; America's Cup Aerobatic Box, San Francisco Bay, San Francisco, CA

    Science.gov (United States)

    2013-09-19

    ... government and the States, or on the distribution of power and responsibilities among the various levels of... Sector San Francisco; telephone (415) 399-3585 or email at D11-PF-MarineEvents@uscg.mil . If you have... ``America's Cup World Series'' regattas in 2012 and the ``Louis Vuitton Cup,'' ``Red Bull Youth America's...

  2. Potential Inundation due to Rising Sea Levels in the San Francisco Bay Region

    Science.gov (United States)

    Knowles, Noah

    2009-01-01

    An increase in the rate of sea level rise is one of the primary impacts of projected global climate change. To assess potential inundation associated with a continued acceleration of sea level rise, the highest resolution elevation data available were assembled from various sources and mosaicked to cover the land surfaces of the San Francisco Bay region. Next, to quantify high water levels throughout the bay, a hydrodynamic model of the San Francisco Estuary was driven by a projection of hourly water levels at the Presidio. This projection was based on a combination of climate model outputs and empirical models and incorporates astronomical, storm surge, El Niño, and long-term sea level rise influences. Based on the resulting data, maps of areas vulnerable to inundation were produced, corresponding to specific amounts of sea level rise and recurrence intervals. These maps portray areas where inundation will likely be an increasing concern. In the North Bay, wetland survival and developed fill areas are at risk. In Central and South bays, a key feature is the bay-ward periphery of developed areas that would be newly vulnerable to inundation. Nearly all municipalities adjacent to South Bay face this risk to some degree. For the Bay as a whole, as early as 2050 under this scenario, the one-year peak event nearly equals the 100-year peak event in 2000. Maps of vulnerable areas are presented and some implications discussed.

  3. Developing a spatially-explicit climate adaptation framework for estuarine ecosystems of the San Francisco Bay: climate adaptation for decision support

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report provides recommended resource allocations for conserving four subregions of SanFrancisco (SF) Bay, including North Bay, Suisun, Central Bay and South...

  4. USGS measurements of water quality in San Francisco Bay (CA), 1969-2015

    Science.gov (United States)

    Cloern, James E.; Schraga, Tara

    2016-01-01

    The U.S. Geological Survey maintains a program of water-quality studies in San Francisco Bay (CA) that began in 1969. This Data Release makes available all measurements made from 1969 through 2015. Water-quality constituents include salinity, temperature, light attenuation coefficient, and concentrations of chlorophyll-a, dissolved oxygen, suspended particulate matter, nitrate, nitrite, ammonium, silicate and phosphate. Water samples are collected at 37 fixed sampling locations along a 145-km transect from lower South San Francisco Bayo to the lower Sacramento River. A map of sampling locations is available on the project website at: https://sfbay.wr.usgs.gov/access/wqdata/overview/wherewhen/stnmap.html.

  5. Creating Safe Growth Strategies for the San Francisco Bay Area

    Science.gov (United States)

    Report from a technical assistance project with the Association of Bay Area Governments to develop strategies to ensure that growth in the region is resilient to hazards such as earthquakes and sea level rise, but also affordable and transit accessible.

  6. Copper, iron and the organic ligands that bind them - updates from San Francisco Bay and beyond

    Science.gov (United States)

    Buck, K. N.; Bundy, R.; Biller, D.; Bruland, K. W.; Barbeau, K.

    2015-12-01

    Building on more than 30 years of measurements in San Francisco Bay by Russ Flegal and others, the concentrations of dissolved manganese, iron, cobalt, nickel, copper, zinc, cadmium and lead were determined from a suite of water quality monitoring program stations in North, Central and South Bay using inductively coupled plasma- mass spectrometry following preconcentration on a Nobias-chelate PA1 resin. Given the importance of organic ligands in governing iron solubility and copper bioavailability in natural waters, the organic complexation of dissolved iron and copper in these samples was determined from multiple analytical windows applied to competitive ligand exchange- adsorptive cathodic stripping voltammetry. This study constitutes the first dataset of iron speciation in San Francisco Bay and expands upon prior work evaluating the potential for copper toxicity in this urbanized estuary. Recent advances in voltammetric techniques emerging from a Scientific Committee on Oceanic Research (SCOR) working group on metal-binding ligands in the marine environment, and insights gained from high-resolution ligand measurements from the U.S. GEOTRACES program, highlight how metal-binding ligands in San Francisco Bay compare with those of the coastal and open ocean.

  7. Upland habitat weed management plan for the Don Edwards San Francisco Bay National Wildlife Refuge Environmental Education Center

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The purpose of this plan is to outline the current status of invasive weeds at the Don Edwards San Francisco Bay NWR Environmental Education Center and to provide a...

  8. The relationship between the fluctuations of bird populations and the salinities of ponds in South San Francisco Bay

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes a bi-monthly census of salinities and bird numbers taken in the salt evaporation ponds on the San Francisco Bay National Wildlife Refuge. A...

  9. National Wildlife Refuge Visitor Survey 2012: Individual refuge results for Don Edwards San Francisco Bay National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes the National Wildlife Refuge Visitor Survey for Don Edwards San Francisco Bay National Wildlife Refuge and is part of the USGS Data Series...

  10. Environmental Sensitivity Index (ESI) Atlas: San Francisco Bay - 1998, maps and geographic information systems data (NODC Accession 0036884)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set comprises the Environmental Sensitivity Index (ESI) maps for the shoreline of San Francisco Bay. ESI data characterize estuarine environments and...

  11. Long-Term Earthquake Forecasts in the San Francisco Bay Area: A Contrarian Perspective

    Science.gov (United States)

    Lindh, A. G.

    2003-12-01

    In historic time the San Francisco Bay Area (SFBA) has been the site of four large earthquakes, including the M7.8 1906 San Francisco earthquake, and most recently, the M6.9 1989 Loma Prieta earthquake. Of the eight major fault segments considered here, two have not experienced large earthquakes in about 200 years, and the SF Peninsula segment of the 1906 rupture on the San Andreas appears from my calculations to be close to fully reloaded as well. I have used simple geophysical and statistical models (elastic rebound model and Weibull distribution) to estimate the probability of large earthquakes (M7 or larger) in the SFBA in the coming decades. I have used seismicity, geology, and geodesy to estimate segment boundaries, recurrence intervals, and the associated uncertainties. The results indicate that the SFBA has an approximately 80% chance of a large earthquake in the next 30 years, with four segments dominating the 30 yr probabilities; San Francisco Peninsula (32%), Southern Hayward (39%), Northern Hayward (28%) and Rodgers Cr (30%). Because of the proximity of these four segments to the urban portions of San Francisco and Oakland, the probability of these most vulnerable areas experiencing strong ground motion (an M7 within 25 km or less) one or more times within the next 30 years is about 70%. Because of the breadth and quality of our understanding of the earthquake machine in the SFBA, these probabilities depend in large part on the intrinsic variance in the earthquake recurrence process itself -- most conveniently expressed as the ratio of the standard deviation to the mean recurrence time, or intrinsic coefficient of variation (CVI). I have applied a new approach to estimating CVI, using the time since the last characteristic event (the "open-interval") on well characterized segments. Combined with an estimate of the mean recurrence time on each segment, an estimate of the likelihood of each open interval can be computed, and a simple maximum likelihood

  12. Temporal and spatial distributions of sediment mercury at salt pond wetland restoration sites, San Francisco Bay, CA, USA

    Science.gov (United States)

    Miles, A.K.; Ricca, M.A.

    2010-01-01

    Decommissioned agricultural salt ponds within south San Francisco Bay, California, are in the process of being converted to habitat for the benefit of wildlife as well as water management needs and recreation. Little is known of baseline levels of contaminants in these ponds, particularly mercury (Hg), which has a well established legacy in the Bay. In this study we described spatial and short-term temporal variations in sediment Hg species concentrations within and among the Alviso and Eden Landing salt ponds in the southern region of San Francisco Bay. We determined total Hg (Hgt) and methylmercury (MeHg) in the top 5 cm of sediment of most ponds in order to establish baseline conditions prior to restoration, sediment Hgt concentrations in a subset of these ponds after commencement of restoration, and variation in MeHg concentrations relative to sediment Hgt, pH, and total Fe concentrations and water depth and salinity in the subset of Alviso ponds. Inter-pond differences were greatest within the Alviso pond complex, where sediment Hgt concentrations averaged (arithmetic mean) 0.74 ??g/g pre and 1.03 ??g/g post-restoration activity compared to 0.11 ??g/g pre and post at Eden Landing ponds. Sediment Hgt levels at Alviso were fairly stable temporally and spatially, whereas MeHg levels were variable relative to restoration activities across time and space. Mean (arithmetic) sediment MeHg concentrations increased (2.58 to 3.03 ng/g) in Alviso and decreased (2.20 to 1.03 ng/g) in Eden Landing restoration ponds during the study. Differences in MeHg levels were related to water depth and pH, but these relationships were not consistent between years or among ponds and were viewed with caution. Factors affecting MeHg levels in these ponds (and in general) are highly complex and require in-depth study to understand.

  13. Probabilistic estimation of numbers and costs of future landslides in the San Francisco Bay region

    Science.gov (United States)

    Crovelli, R.A.; Coe, J.A.

    2009-01-01

    We used historical records of damaging landslides triggered by rainstorms and a newly developed Probabilistic Landslide Assessment Cost Estimation System (PLACES) to estimate the numbers and direct costs of future landslides in the 10-county San Francisco Bay region. Historical records of damaging landslides in the region are incomplete. Therefore, our estimates of numbers and costs of future landslides are minimal estimates. The estimated mean annual number of future damaging landslides for the entire 10-county region is about 65. Santa Cruz County has the highest estimated mean annual number of damaging future landslides (about 18), whereas Napa, San Francisco, and Solano Counties have the lowest estimated mean numbers of damaging landslides (about 1 each). The estimated mean annual cost of future landslides in the entire region is about US $14.80 million (year 2000 $). The estimated mean annual cost is highest for San Mateo County ($3.24 million) and lowest for Solano County ($0.18 million). The annual per capita cost for the entire region will be about $2.10. Santa Cruz County will have the highest annual per capita cost at $8.45, whereas San Francisco County will have the lowest per capita cost at $0.31. Normalising costs by dividing by the percentage of land area with slopes equal to or greater than 17% indicates that San Francisco County will have the highest cost per square km ($7,101), whereas Santa Clara County will have the lowest cost per square km ($229). These results indicate that the San Francisco Bay region has one of the highest levels of landslide risk in the United States. Compared with landslide cost estimates from the rest of the world, the risk level in the Bay region seems high, but not exceptionally high.

  14. Long-period building response to earthquakes in the San Francisco Bay Area

    Science.gov (United States)

    Olsen, A.H.; Aagaard, B.T.; Heaton, T.H.

    2008-01-01

    This article reports a study of modeled, long-period building responses to ground-motion simulations of earthquakes in the San Francisco Bay Area. The earthquakes include the 1989 magnitude 6.9 Loma Prieta earthquake, a magnitude 7.8 simulation of the 1906 San Francisco earthquake, and two hypothetical magnitude 7.8 northern San Andreas fault earthquakes with hypocenters north and south of San Francisco. We use the simulated ground motions to excite nonlinear models of 20-story, steel, welded moment-resisting frame (MRF) buildings. We consider MRF buildings designed with two different strengths and modeled with either ductile or brittle welds. Using peak interstory drift ratio (IDR) as a performance measure, the stiffer, higher strength building models outperform the equivalent more flexible, lower strength designs. The hypothetical magnitude 7.8 earthquake with hypocenter north of San Francisco produces the most severe ground motions. In this simulation, the responses of the more flexible, lower strength building model with brittle welds exceed an IDR of 2.5% (that is, threaten life safety) on 54% of the urban area, compared to 4.6% of the urban area for the stiffer, higher strength building with ductile welds. We also use the simulated ground motions to predict the maximum isolator displacement of base-isolated buildings with linear, single-degree-of-freedom (SDOF) models. For two existing 3-sec isolator systems near San Francisco, the design maximum displacement is 0.5 m, and our simulations predict isolator displacements for this type of system in excess of 0.5 m in many urban areas. This article demonstrates that a large, 1906-like earthquake could cause significant damage to long-period buildings in the San Francisco Bay Area.

  15. Integrating Fluvial and Oceanic Drivers in Operational Flooding Forecasts for San Francisco Bay

    Science.gov (United States)

    Herdman, Liv; Erikson, Li; Barnard, Patrick; Kim, Jungho; Cifelli, Rob; Johnson, Lynn

    2016-04-01

    The nine counties that make up the San Francisco Bay area are home to 7.5 million people and these communties are susceptible to flooding along the bay shoreline and inland creeks that drain to the bay. A forecast model that integrates fluvial and oceanic drivers is necessary for predicting flooding in this complex urban environment. The U.S. Geological Survey ( USGS) and National Weather Service (NWS) are developing a state-of-the-art flooding forecast model for the San Francisco Bay area that will predict watershed and ocean-based flooding up to 72 hours in advance of an approaching storm. The model framework for flood forecasts is based on the USGS-developed Coastal Storm Modeling System (CoSMoS) that was applied to San Francisco Bay under the Our Coast Our Future project. For this application, we utilize Delft3D-FM, a hydrodynamic model based on a flexible mesh grid, to calculate water levels that account for tidal forcing, seasonal water level anomalies, surge and in-Bay generated wind waves from the wind and pressure fields of a NWS forecast model, and tributary discharges from the Research Distributed Hydrologic Model (RDHM), developed by the NWS Office of Hydrologic Development. The flooding extent is determined by overlaying the resulting water levels onto a recently completed 2-m digital elevation model of the study area which best resolves the extensive levee and tidal marsh systems in the region. Here we present initial pilot results of hindcast winter storms in January 2010 and December 2012, where the flooding is driven by oceanic and fluvial factors respectively. We also demonstrate the feasibility of predicting flooding on an operational time scale that incorporates both atmospheric and hydrologic forcings.

  16. Hydraulic modeling and scour analysis for the San Francisco - Oakland Bay Bridge

    Science.gov (United States)

    Shelden, J.G.; Smith, E.D.; Sheppard, D.M.; Odeh, M.

    2004-01-01

    A study was conducted to determine potential maximum scour depths for the foundations of the replacement east span of the San Francisco-Oakland Bay Bridge, as part of the ongoing structural design. This effort presented unique challenges as strong tidal currents, large depths, and cohesive bottom sediments characterize the site. The authors met these challenges with a multi-faceted approach to the problem. First, design current velocities were determined using a two-dimensional hydrodynamic model of San Francisco Bay in conjunction with ADCP hydrographic surveys. Analytical scour calculations were performed and live-bed flume tests of the proposed foundations were also conducted. Finally, two separate methodologies were used to interpret the physical model tests in order to calculate potential scour depths around the foundations. Copyright ASCE 2004.

  17. Aquatic macroinvertebrate communities of natural and ditched potholes in a San Francisco Bay salt marsh

    Science.gov (United States)

    Barnby, Mark A.; Collins, Joshua N.; Resh, Vincent H.

    1985-03-01

    Differences in macroinvertebrate community structure and composition were examined from April 1980 to March 1981 in three potholes that had been ditched for mosquito control and three natural (i.e. unditched) potholes, which are located in a San Francisco Bay, California, U.S.A. salt marsh. Measurements of incipient tidal flooding into potholes (i.e. pothole inundation threshold) indicated that these sites comprise a gradient of tidal influences. Exponential decreases in the frequency and duration of tidal inundation corresponded to linear increases in inundation threshold. Since ditched study sites had low thresholds they tended to be more uniformly and regularly influenced by tides, were less saline, had less variable temperature regimens, and supported less filamentous algae than natural potholes. Habitat conditions were generally more similar among ditched than unditched potholes, but environmental conditions were most severe at natural sites near the upper limit of the inundation threshold gradient, where some potholes desiccate during the dry season each year. Differences in macroinvertebrate communities corresponded to differences in habitat conditions. Species richness and diversity (Simpson's Index) were generally highest near the middle of the inundation threshold gradient, which is a pattern predicted by the Intermediate Disturbance Hypothesis. Analysis of faunal composition using discriminant functions indicated more similarity among potholes located at the lowest positions of the inundation gradient than among potholes with intermediate thresholds. Since ditching lowers the inundation thresholds of potholes, it reduces species richness and diversity, while increasing faunal similarity. As a result, extensive ditching to control salt marsh mosquitoes can reduce the overall complexity of lentic macroinvertebrate communities.

  18. Waveform tomography of crustal structure in the south San Francisco Bay region

    Science.gov (United States)

    Pollitz, F.F.; Fletcher, J.P.

    2005-01-01

    We utilize a scattering-based seismic tomography technique to constrain crustal tructure around the southern San Francisco Bay region (SFBR). This technique is based on coupled traveling wave scattering theory, which has usually been applied to the interpretation of surface waves in large regional-scale studies. Using fully three-dimensional kernels, this technique is here applied to observed P, S, and surface waves of intermediate period (3-4 s dominant period) observed following eight selected regional events. We use a total of 73 seismograms recorded by a U.S. Geological Survey short-period seismic array in the western Santa Clara Valley, the Berkeley Digital Seismic Network, and the Northern California Seismic Network. Modifications of observed waveforms due to scattering from crustal structure include (positive or negative) amplification, delay, and generation of coda waves. The derived crustal structure explains many of the observed signals which cannot be explained with a simple layered structure. There is sufficient sensitivity to both deep and shallow crustal structure that even with the few sources employed in the present study, we obtain shallow velocity structure which is reasonably consistent with previous P wave tomography results. We find a depth-dependent lateral velocity contrast across the San Andreas fault (SAF), with higher velocities southwest of the SAF in the shallow crust and higher velocities northeast of the SAF in the midcrust. The method does not have the resolution to identify very slow sediment velocities in the upper approximately 3 km since the tomographic models are smooth at a vertical scale of about 5 km. Copyright 2005 by the American Geophysical Union.

  19. Broadband Waveform Modeling to Evaluate the USGS Seismic Velocity Model for the San Francisco Bay Area

    Science.gov (United States)

    Rodgers, A.; Petersson, A.; Nilsson, S.; Sjogreen, B.; McCandless, K.

    2006-12-01

    As part of the 1906 San Francisco earthquake centenary, the USGS developed a three-dimensional seismic velocity and attenuation model for Northern California based on detailed geologic and geophysical constraints. The model was used to predict ground motions for the 1906 rupture. In this study we evaluate the model to assess its ability to accurately predict ground motions from moderate earthquakes recorded on broadband stations. Satisfactory prediction of ground motions from these events will provide hope for accurate modeling of future scenario earthquakes. Simulations were performed on large parallel computer(s) with a new elastic finite difference code developed at LLNL. We simulated broadband ground motions (0-0.25 Hz) for several moderate (magnitude 3.5-5.0) earthquakes in the region observed at Berkeley Digital Seismic Network (BDSN) broadband stations. These events are well located and can be modeled with simple point moment tensor sources (taken from the Berkeley Seismological Laboratory catalog), helping to isolate the effects of structure on the waveforms. These data sample the region's diverse tectonic structures, such as the bay muds, sedimentary basins and hard rock complexes. Preliminary results indicate that the simulations reproduce many important features in the data. For example, observed long duration surface waves are often predicted for complex paths (traveling across contrasting structures) and through sedimentary basins. Excellent waveform fits were frequently obtained for long-period comparisons (0.02-0.1) and good fits were often obtained for shorter periods. We will attempt higher frequency simulations to test the ability of the model to match the high frequency response. Finally, we performed large scenario earthquake simulations for the Hayward Fault. These simulations predict large amplifications across the Santa Clara and San Ramon/Livermore Valley sedimentary basins and with the Sacramento/San Joaquin River Delta.

  20. Observations of fallout from the Fukushima reactor accident in San Francisco Bay area rainwater.

    Directory of Open Access Journals (Sweden)

    Eric B Norman

    Full Text Available We have observed fallout from the recent Fukushima Dai-ichi reactor accident in samples of rainwater collected in the San Francisco Bay area. Gamma ray spectra measured from these samples show clear evidence of fission products--(131,132I, (132Te, and (134,137Cs. The activity levels we have measured for these isotopes are very low and pose no health risk to the public.

  1. The Long Road From Babylon To Brentwood: Crisis and Restructuring in the San Francisco Bay Area

    OpenAIRE

    2012-01-01

    AbstractThis dissertation integrates policy analysis, archival research, ethnographic field work, GIS mapping and statistical analysis to build a broad geo-historical understanding of the role of planning, policy, capital and race in the production of the foreclosure crisis in the San Francisco Bay Area. It begins from the premise that an explanation of the foreclosure crisis that focuses solely on either finance capital or the action of homeowners misses the critical importance of history, g...

  2. Observations of Fallout from the Fukushima Reactor Accident in San Francisco Bay Area Rainwater

    CERN Document Server

    Norman, Eric B; Chodash, Perry A

    2011-01-01

    We have observed fallout from the recent Fukushima Dai-ichi reactor accident in samples of rainwater collected in the San Francisco Bay area. Gamma ray spectra measured from these samples show clear evidence of fission products - 131,132I, 132Te, and 134,137Cs. The activity levels we have measured for these isotopes are very low and pose no health risk to the public.

  3. Sediment transport in the San Francisco Bay Coastal System: an overview

    Science.gov (United States)

    Barnard, Patrick L.; Schoellhamer, David H.; Jaffe, Bruce E.; McKee, Lester J.; Barnard, P.L.; Jaffee, B.E.; Schoellhamer, D.H.

    2013-01-01

    The papers in this special issue feature state-of-the-art approaches to understanding the physical processes related to sediment transport and geomorphology of complex coastal–estuarine systems. Here we focus on the San Francisco Bay Coastal System, extending from the lower San Joaquin–Sacramento Delta, through the Bay, and along the adjacent outer Pacific Coast. San Francisco Bay is an urbanized estuary that is impacted by numerous anthropogenic activities common to many large estuaries, including a mining legacy, channel dredging, aggregate mining, reservoirs, freshwater diversion, watershed modifications, urban run-off, ship traffic, exotic species introductions, land reclamation, and wetland restoration. The Golden Gate strait is the sole inlet connecting the Bay to the Pacific Ocean, and serves as the conduit for a tidal flow of ~ 8 × 109 m3/day, in addition to the transport of mud, sand, biogenic material, nutrients, and pollutants. Despite this physical, biological and chemical connection, resource management and prior research have often treated the Delta, Bay and adjacent ocean as separate entities, compartmentalized by artificial geographic or political boundaries. The body of work herein presents a comprehensive analysis of system-wide behavior, extending a rich heritage of sediment transport research that dates back to the groundbreaking hydraulic mining-impact research of G.K. Gilbert in the early 20th century.

  4. 77 FR 50921 - Safety Zone: Bay Bridge Load Transfer Safety Zone, San Francisco Bay, San Francisco, CA

    Science.gov (United States)

    2012-08-23

    ... Department of Homeland Security FR Federal Register NPRM Notice of Proposed Rulemaking A. Regulatory History... and Interference with Constitutionally Protected Property Rights. 9. Civil Justice Reform This rule... Yerba Buena Island, California as depicted in National Oceanic and Atmospheric Administration...

  5. Broad-spectrum monitoring strategies for predicting occult precipitation contribution to water balance in a coastal watershed in California: Ground-truthing, areal monitoring and isotopic analysis of fog in the San Francisco Bay region

    Science.gov (United States)

    Koohafkan, M.; Thompson, S. E.; Leonardson, R.; Dufour, A.

    2013-12-01

    We showcase a fog monitoring study designed to quantitatively estimate the contribution of summer fog events to the water balance of a coastal watershed managed by the San Francisco Public Utilities Commission. Two decades of research now clearly show that fog and occult precipitation can be major contributors to the water balance of watersheds worldwide. Monitoring, understanding and predicting occult precipitation is therefore as hydrologically compelling as forecasting precipitation or evaporation, particularly in the face of climate variability. We combine ground-based monitoring and collection strategies with remote sensing technologies, time-lapse imagery, and isotope analysis to trace the ';signature' of fog in physical and ecological processes. Spatial coverage and duration of fog events in the watershed is monitored using time-lapse cameras and leaf wetness sensors strategically positioned to provide estimates of the fog bank extent and cloud base elevation, and this fine-scale data is used to estimate transpiration suppression by fog and is examined in the context of regional climate through the use of satellite imagery. Soil moisture sensors, throughfall collectors and advective fog collectors deployed throughout the watershed provide quantitative estimates of fog drip contribution to soil moisture and plants. Fog incidence records and streamflow monitoring provide daily estimates of fog contribution to streamflow. Isotope analysis of soil water, fog drip, stream water and vegetation samples are used to probe for evidence of direct root and leaf uptake of fog drip by plants. Using this diversity of fog monitoring methods, we develop an empirical framework for the inclusion of fog processes in water balance models.

  6. Suspended sediment and sediment-associated contaminants in San Francisco Bay

    Science.gov (United States)

    Schoellhamer, D.H.; Mumley, T.E.; Leatherbarrow, J.E.

    2007-01-01

    Water-quality managers desire information on the temporal and spatial variability of contaminant concentrations and the magnitudes of watershed and bed-sediment loads in San Francisco Bay. To help provide this information, the Regional Monitoring Program for Trace Substances in the San Francisco Estuary (RMP) takes advantage of the association of many contaminants with sediment particles by continuously measuring suspended-sediment concentration (SSC), which is an accurate, less costly, and more easily measured surrogate for several trace metals and organic contaminants. Continuous time series of SSC are collected at several sites in the Bay. Although semidiurnal and diurnal tidal fluctuations are present, most of the variability of SSC occurs at fortnightly, monthly, and semiannual tidal time scales. A seasonal cycle of sediment inflow, wind-wave resuspension, and winnowing of fine sediment also is observed. SSC and, thus, sediment-associated contaminants tend to be greater in shallower water, at the landward ends of the Bay, and in several localized estuarine turbidity maxima. Although understanding of sediment transport has improved in the first 10 years of the RMP, determining a simple mass budget of sediment or associated contaminants is confounded by uncertainties regarding sediment flux at boundaries, change in bed-sediment storage, and appropriate modeling techniques. Nevertheless, management of sediment-associated contaminants has improved greatly. Better understanding of sediment and sediment-associated contaminants in the Bay is of great interest to evaluate the value of control actions taken and the need for additional controls. ?? 2007 Elsevier Inc. All rights reserved.

  7. Comparison of sediment supply to San Francisco Bay from Coastal and Sierra Nevada watersheds

    Science.gov (United States)

    McKee, L. J.

    2012-12-01

    Quantifying suspended sediment loads is of paramount importance for managing the world's estuaries. To address this information need, a comprehensive analysis was completed for the San Francisco Bay system by combining a number of formerly disparate data sets. Suspended sediment and optical backscatter measurements near the head of the estuary were used to generate a continuous suspended sediment concentration record. In addition, periodic measurements of velocity and suspended sediment variation in the cross-section were used to validate the use of point samples collected on the edge of the channel for generating loads. Suspended sediment loads were determined by combining daily averaged suspended sediment concentrations with daily flow estimates adjusting for dispersive loads. Sediment loads from 482 small drainages around the Bay were determined using 235 station years of suspended sediment data covering 38 watershed locations, regression analysis, and simple modeling. Over 16 years, net annual load to the head of the estuary from its 154000 km2 watershed varied from 0.13-2.58 (mean = 0.89) million metric t, or 5.8 t/km2/yr. Small drainages in the nine-county Bay Area discharged between 0.089 and 4.35 (mean = 1.43) million metric t with an average yield of 175 metric t/km2/yr. Our results indicate that external loads to the Bay are dominated by the many hundreds of urbanized and tectonically active tributaries that drain just 8145 km2 adjacent to the Bay and that during only 5 years did sediment loads from the Central Valley likely exceed loads from the sum of the local smaller drainages. If San Francisco Bay is typical of other estuaries in active tectonic or climatically variable coastal regimes, managers responsible for water quality, sediment accumulating in shipping channels, or restoring wetlands in the world's estuaries may need to more carefully account for proximal small urban drainages that may dominate allochthonous sediment supply.

  8. Coupling Fluvial and Oceanic Drivers in Flooding Forecasts for San Francisco Bay

    Science.gov (United States)

    Herdman, L.; Kim, J.; Cifelli, R.; Barnard, P.; Erikson, L. H.; Johnson, L. E.; Chandrasekar, V.

    2016-12-01

    San Francisco Bay is a highly urbanized estuary and the surrounding communities are susceptible to flooding along the bay shoreline and inland rivers and creeks that drain to the Bay. A forecast model that integrates fluvial and oceanic drivers is necessary for predicting flooding in this complex urban environment. This study introduces the state-of-the-art coupling of the USGS Coastal Storm Modeling System (CoSMoS) with the NWS Research Distributed Hydrologic Model (RDHM) for San Francisco Bay. For this application, we utilize Delft3D-FM, a hydrodynamic model based on a flexible mesh grid, to calculate water levels that account for tidal forcing, seasonal water level anomalies, surge and in-Bay generated wind waves from the wind and pressure fields of a NWS forecast model. The tributary discharges from RDHM are dynamic, meteorologically driven allowing for operational use of CoSMoS which has previously relied on statistical estimates of river discharge. The flooding extent is determined by overlaying the resulting maximum water levels onto a recently updated 2-m digital elevation model of the study area which best resolves the extensive levee and tidal marsh systems in the region. The results we present here are focused on the interaction of the Bay and the Napa River watershed. This study demonstrates the interoperability of the CoSMoS and RDHM prediction models. We also use this pilot region to examine storm flooding impacts in a series of storm scenarios that simulate 5-100yr return period events in terms of either coastal or fluvial events. These scenarios demonstrate the wide range of possible flooding outcomes considering rainfall recurrence intervals, soil moisture conditions, storm surge, wind speed, and tides (spring and neap). With a simulated set of over 25 storm scenarios we show how the extent, level, and duration of flooding is dependent on these atmospheric and hydrologic parameters and we also determine a range of likely flood events.

  9. Geology of the Monterey Bay region, California

    Science.gov (United States)

    Greene, H. Gary

    1977-01-01

    Geophysical data and sea floor samples collected from the continental shelf and slope between Ano Nuevo Point and Point Sur, California indicate that the Monterey Bay region has had a complex late Cenozoic tectonic history. Uplift and depression have produced a succession of regressive and transgressive sedimentary units, while contemporaneous right-slip along faults of the San Andreas system have offset major structural and lithologic elements. This deformation produced three regional and several local unconformities within upper Tertiary rocks and initiated development of a canyon system that today includes the Monterey, Ascension, Carmel, and other large submarine canyons. The Tertiary stratigraphy of the offshore Monterey Bay area is divided into two provinces by a major structural boundary, the north-trending Palo Colorado-San Gregorio fault zone. East of this zone in the offshore are four seismically distinct sequences that can be correlated with major sequences onshore. These sequences comprise (1) pre-Tertiary basement, and (2) middle Miocene, (3) upper Miocene to Pliocene, and (4) upper Pliocene to Holocene sedimentary intervals. Each of the latter three sequences is bounded by unconformities, as is its counterpart on land. Only Neogene sedimentary rocks are present offshore; Paleogene units, if originally present, have been removed completely by pre-middle Miocene erosion. An extensive erosional surface was cut during Zemorrian time into the late Mesozoic granitic basement rocks. Incised into this surface are the ancestral Monterey Canyon and an unnamed canyon. Marine sedimentary rocks of upper Miocene and Pliocene age overlie this unconformably and fill the unnamed canyon. Similar rocks also may have once filled Monterey Canyon. Near shore these strata are covered by terrestrial alluvial and eolian deposits, deltaic deposits, marine canyon fill, landslide and slump deposits, and unconsolidated sediments that range in age from upper Pliocene to Holocene

  10. Forecasting Selenium Discharges to the San Francisco Bay-Delta Estuary: Ecological Effects of A Proposed San Luis Drain Extension

    Science.gov (United States)

    Presser, Theresa S.; Luoma, Samuel N.

    2006-01-01

    Selenium discharges to the San Francisco Bay-Delta Estuary (Bay-Delta) could change significantly if federal and state agencies (1) approve an extension of the San Luis Drain to convey agricultural drainage from the western San Joaquin Valley to the North Bay (Suisun Bay, Carquinez Strait, and San Pablo Bay); (2) allow changes in flow patterns of the lower San Joaquin River and Bay-Delta while using an existing portion of the San Luis Drain to convey agricultural drainage to a tributary of the San Joaquin River; or (3) revise selenium criteria for the protection of aquatic life or issue criteria for the protection of wildlife. Understanding the biotransfer of selenium is essential to evaluating effects of selenium on Bay-Delta ecosystems. Confusion about selenium threats to fish and wildlife stem from (1) monitoring programs that do not address specific protocols necessary for an element that bioaccumulates; and (2) failure to consider the full complexity of the processes that result in selenium toxicity. Past studies show that predators are more at risk from selenium contamination than their prey, making it difficult to use traditional methods to predict risk from environmental concentrations alone. This report presents an approach to conceptualize and model the fate and effects of selenium under various load scenarios from the San Joaquin Valley. For each potential load, progressive forecasts show resulting (1) water-column concentration; (2) speciation; (3) transformation to particulate form; (4) particulate concentration; (5) bioaccumulation by invertebrates; (6) trophic transfer to predators; and (7) effects on those predators. Enough is known to establish a first-order understanding of relevant conditions, biological response, and ecological risks should selenium be discharged directly into the North Bay through a conveyance such as a proposed extension of the San Luis Drain. The approach presented here, the Bay-Delta selenium model, determines the mass, fate

  11. San Francisco Bay-Delta bathymetric/topographic digital elevation model (DEM)

    Science.gov (United States)

    Fregoso, Theresa; Wang, Rueen-Fang; Ateljevich, Eli; Jaffe, Bruce E.

    2017-01-01

    bathymetry data collected by the COE and USGS scientists, expanding the DEM to include the northernmost areas of the Sacramento-San Joaquin Delta, and by making use of a two-meter seamless bathymetric/topographic DEM from the USGS EROS Data Center (2013) of the San Francisco Bay region.The resulting 10-meter USGS DEM encompasses the entirety of Suisun Bay, beginning with the Carquinez Strait in the west, east to California Interstate 5, north following the path of the Yolo Bypass and the Sacramento River up to Knights Landing, and the American River northeast to the Nimbus Dam, and south to areas around Tracy. The DEM incorporates the newest available bathymetry data at the time of release, as well as including, at minimum, a 100-meter band of available topography data adjacent to most shorelines. No data areas within the DEM are areas where no elevation data exists, either due to a gap in the land/water interface, or because lidar was collected over standing water that was then cut out of the DEM.Environmental Systems Research Institute, Inc., 2015, Topo to Raster:  http://desktop.arcgis.com/en/desktop/latest/tools/3d-analyst-toolbox/topo-to-raster.htmFoxgrover, A., Smith, R.E., and Jaffe, B.E., 2005, Suisun Bay and Delta Bathymetry: http://sfbay.wr.usgs.gov/sediment/delta/index.htmlUSGS EROS Data Center, 2013, 2 m Coastal National Elevation Dataset: http://topotools.cr.usgs.gov/topobathy_viewer/Wang, R-F., and Ateljevich, E., 2012, A continuous surface elevation map for modeling, chapter 6 in California Department of Water Resources, Methodology for flow and salinity estimates in the Sacramento-San Joaquin Delta and Suisun Marsh, 33rd Annual Progress Report to the StateWater Resources Control Board:  California Department of Water Resources, Bay-Delta Office, Delta Modeling Section, http://baydeltaoffice.water.ca.gov/modeling/deltamodeling/AR2012/Chapter%206_2012_Web.pdf

  12. Quaternary geology of Alameda County, and parts of Contra Costa, Santa Clara, San Mateo, San Francisco, Stanislaus, and San Joaquin counties, California: a digital database

    Science.gov (United States)

    Helley, E.J.; Graymer, R.W.

    1997-01-01

    Alameda County is located at the northern end of the Diablo Range of Central California. It is bounded on the north by the south flank of Mount Diablo, one of the highest peaks in the Bay Area, reaching an elevation of 1173 meters (3,849 ft). San Francisco Bay forms the western boundary, the San Joaquin Valley borders it on the east and an arbitrary line from the Bay into the Diablo Range forms the southern boundary. Alameda is one of the nine Bay Area counties tributary to San Francisco Bay. Most of the country is mountainous with steep rugged topography. Alameda County is covered by twenty-eight 7.5' topographic Quadrangles which are shown on the index map. The Quaternary deposits in Alameda County comprise three distinct depositional environments. One, forming a transgressive sequence of alluvial fan and fan-delta facies, is mapped in the western one-third of the county. The second, forming only alluvial fan facies, is mapped in the Livermore Valley and San Joaquin Valley in the eastern part of the county. The third, forming a combination of Eolian dune and estuarine facies, is restricted to the Alameda Island area in the northwestern corner of the county.

  13. Health cobenefits and transportation-related reductions in greenhouse gas emissions in the San Francisco Bay area.

    Science.gov (United States)

    Maizlish, Neil; Woodcock, James; Co, Sean; Ostro, Bart; Fanai, Amir; Fairley, David

    2013-04-01

    We quantified health benefits of transportation strategies to reduce greenhouse gas emissions (GHGE). Statistics on travel patterns and injuries, physical activity, fine particulate matter, and GHGE in the San Francisco Bay Area, California, were input to a model that calculated the health impacts of walking and bicycling short distances usually traveled by car or driving low-emission automobiles. We measured the change in disease burden in disability-adjusted life years (DALYs) based on dose-response relationships and the distributions of physical activity, particulate matter, and traffic injuries. Increasing median daily walking and bicycling from 4 to 22 minutes reduced the burden of cardiovascular disease and diabetes by 14% (32,466 DALYs), increased the traffic injury burden by 39% (5907 DALYS), and decreased GHGE by 14%. Low-carbon driving reduced GHGE by 33.5% and cardiorespiratory disease burden by less than 1%. Increased physical activity associated with active transport could generate a large net improvement in population health. Measures would be needed to minimize pedestrian and bicyclist injuries. Together, active transport and low-carbon driving could achieve GHGE reductions sufficient for California to meet legislative mandates.

  14. Faults--Drakes Bay and Vicinity Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data of faults for the geologic and geomorphologic map of the Drakes Bay and Vicinity map area, California. The vector data file is...

  15. Folds--Drakes Bay and Vicinity Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data of folds for the geologic and geomorphologic map of the Drakes Bay and Vicinity map area, California. The vector data file is...

  16. Transgressive Contours--Salt Point to Drakes Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the transgressive contours for the Salt Point to Drakes Bay, California, region. The vector file is included in...

  17. Isopachs--Pigeon Point to South Monterey Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the isopachs for the Pigeon Point to South Monterey Bay, California, region. The vector data file is included in...

  18. Faults--Offshore of Half Moon Bay Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for faults for the geologic and geomorphic map of the Offshore of Half Moon Bay map area, California. The vector data file is...

  19. Folds--Offshore of Half Moon Bay Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for folds for the geologic and geomorphic map of the Offshore of Half Moon Bay map area, California. The vector data file is...

  20. Transgressive Contours--Pigeon Point to South Monterey Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the transgressive contours for the Pigeon Point to South Monterey Bay, California, region. The vector file is included in...

  1. Seafloor character--Offshore of Half Moon Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents the seafloor-character map of the Offshore of Half Moon Bay map area, California. The raster data file is included in...

  2. Faults--Offshore of Half Moon Bay Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for faults for the geologic and geomorphic map of the Offshore of Half Moon Bay map area, California. The vector data file is...

  3. Sediment Thickness--Pigeon Point to South Monterey Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the sediment-thickness map of the Pigeon Point to South Monterey Bay, California, region. The raster data file is included in...

  4. Backscatter A [8101]--Drakes Bay and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Drakes bay and Vicinity map area, California. Backscatter data are provided as separate grids...

  5. Backscatter A [8101]--Offshore Half Moon Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Half Moon Bay map area, California. Backscatter data are provided as two...

  6. Folds--Drakes Bay and Vicinity Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data of folds for the geologic and geomorphologic map of the Drakes Bay and Vicinity map area, California. The vector data file is...

  7. Faults--Drakes Bay and Vicinity Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data of faults for the geologic and geomorphologic map of the Drakes Bay and Vicinity map area, California. The vector data file is...

  8. Backscatter B [Swath]--Drakes Bay and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Drakes bay and Vicinity map area, California. Backscatter data are provided as separate grids...

  9. Habitat--Offshore of Half Moon Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the habitat map of the seafloor of the Offshore of Half Moon Bay map area, California. The polygon shapefile is included in...

  10. Isopachs--Pigeon Point to South Monterey Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the isopachs for the Pigeon Point to South Monterey Bay, California, region. The vector data file is included in...

  11. Transgressive Contours--Pigeon Point to South Monterey Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the transgressive contours for the Pigeon Point to South Monterey Bay, California, region. The vector file is included in...

  12. Sediment Thickness--Pigeon Point to South Monterey Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the sediment-thickness map of the Pigeon Point to South Monterey Bay, California, region. The raster data file is included in...

  13. Seafloor character--Offshore of Half Moon Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents the seafloor-character map of the Offshore of Half Moon Bay map area, California. The raster data file is included in...

  14. Depth to Transition--Salt Point to Drakes Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the depth-to-transition map of the Salt Point to Drakes Bay, California, region. The raster data file is included in...

  15. Backscatter C [7125]--Drakes Bay and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Drakes bay and Vicinity map area, California. Backscatter data are provided as separate grids...

  16. Folds--Offshore of Half Moon Bay Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for folds for the geologic and geomorphic map of the Offshore of Half Moon Bay map area, California. The vector data file is...

  17. Isopachs--Salt Point to Drakes Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the sediment-thickness map of the Salt Point to Drakes Bay, California, region. The raster data file is included in...

  18. Habitat--Offshore of Half Moon Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the habitat map of the seafloor of the Offshore of Half Moon Bay map area, California. The polygon shapefile is included in...

  19. Backscatter B [7125]--Offshore Half Moon Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Half Moon Bay map area, California. Backscatter data are provided as two...

  20. Backscatter A [8101]--Drakes Bay and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Drakes bay and Vicinity map area, California. Backscatter data are provided as separate grids...

  1. Backscatter C [7125]--Drakes Bay and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Drakes bay and Vicinity map area, California. Backscatter data are provided as separate grids...

  2. Input, flux, and persistence of six select pesticides in San Francisco Bay

    Science.gov (United States)

    Kuivila, K.M.; Jennings, B.E.

    2007-01-01

    Temporal patterns of pesticide inputs to San Francisco Bay were identified and correlated with timing of application and transport mechanism. Fluxes were calculated from measured concentrations and estimated flow. Persistence of the pesticides under typical riverine or estuarine conditions were estimated from laboratory experiments. Simazine was detected most frequently and had the highest flux into the Bay, which could be explained by its continuous use and long half-life. In comparison, diazinon was detected at lower concentrations and had a lower flux which corresponded to its lower use and shorter half-life. The order-of-magnitude lower fluxes of carbofuran and methidathion corresponded to their lower use and expected hydrolysis. Molinate was detected at the highest concentration but its flux was lower than expected, considering its very high use and persistence in the laboratory experiments. Additional loss of molinate is likely to occur from volatilization and photodegradation on the rice fields. Although thiobencarb had the second highest use, it had the lowest flux of the six pesticides, which can be attributed to its loss via hydrolysis, photodegradation, volatilization, and sorption to sediments. Fluxes into San Francisco Bay were equal to or greater than those reported for other estuaries, except for the Gulf of Mexico. ?? 2007 Taylor & Francis.

  3. Deep Borehole Instrumentation Along San Francisco Bay Bridges: 1996 - 2003 and Strong Ground Motion Systhesis Along the San Francisco/Oakland Bay Bridge

    Energy Technology Data Exchange (ETDEWEB)

    Hutchings, L; Foxall, W; Kasameyer, P; larsen, S; Hayek, C; Tyler-Turpin, C; Aquilino, J; Long, L

    2005-04-22

    As a result of collaboration between the Berkeley Seismographic Station, Lawrence Livermore National Laboratory, and Caltrans, instrument packages have been placed in bedrock in six boreholes and two surface sites along the San Francisco/Oakland Bay Bridge. Since 1996 over 200 local earthquakes have been recorded. Prior to this study few seismic recording instruments existed in bed-rock in San Francisco Bay. We utilized the data to perform analysis of ground motion variability, wave passage, site response, and up-and down-hole wave propagation along the Bay Bridge. We also synthesized strong ground motion at nine locations along the Bay Bridge. Key to these studies is LLNL's effort to exploit the information available in weak ground motions (generally from earthquakes < M=4.0) to enhance predictions of seismic hazards. We found that Yerba Island has no apparent site response at the surface relative to a borehole site. The horizontal to vertical spectral ratio method best revealed no site response, while the complex signal spectral ratio method had the lowest variance for spectral ratios and best predicted surface recordings when the borehole recording was used as input. Both methods identified resonances at about the same frequencies. Regional attenuation results in a significant loss of high frequencies in both surface and borehole recordings. Records are band limited at near 3 Hz. Therefore a traditional rock outcrop site response, flat to high frequency in displacement, is not available. We applied a methodology to predict and synthesize strong ground motion along the San Francisco/Oakland Bay Bridge from a M=7.25 earthquake along the Hayward fault, about12 km distant. We synthesized for three-components and broad-band (0.0-25.0 Hz) ground motion accelerations, velocities, and displacements. We examined two different possible rupture scenarios, a ''mean'' and ''one standard deviation'' model. We combined the high

  4. California State Waters Map Series: offshore of Half Moon Bay, California

    Science.gov (United States)

    Cochrane, Guy R.; Dartnell, Peter; Greene, H. Gary; Johnson, Samuel Y.; Golden, Nadine E.; Hartwell, Stephen R.; Dieter, Bryan E.; Manson, Michael W.; Sliter, Ray W.; Ross, Stephanie L.; Watt, Janet T.; Endris, Charles A.; Kvitek, Rikk G.; Phillips, Eleyne L.; Erdey, Mercedes D.; Chin, John L.; Bretz, Carrie K.

    2014-01-01

    In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Offshore of Half Moon Bay map area is located in northern California, on the Pacific coast of the San Francisco Peninsula about 40 kilometers south of the Golden Gate. The city of Half Moon Bay, which is situated on the east side of the Half Moon Bay embayment, is the nearest significant onshore cultural center in the map area, with a population of about 11,000. The Pillar Point Harbor at the north edge of Half Moon Bay offers a protected landing for boats and provides other marine infrastructure. The map area lies offshore of the Santa Cruz Mountains, part of the northwest-trending Coast Ranges that run roughly parallel to the San Andreas Fault Zone. The Santa Cruz Mountains lie between the San Andreas Fault Zone and the San Gregorio Fault system. The flat coastal area, which is the most recent of numerous marine terraces, was formed by wave erosion about 105 thousand years ago. The higher elevation of this same terrace west of the Half Moon Bay Airport is caused by uplift on the Seal Cove Fault, a splay of the San Gregorio Fault Zone. Although originally incised into the rising terrain horizontally, the ancient terrace surface has been gently folded into a northwest-plunging syncline by

  5. Insights into microbial communities involved in mercury methylation in the San Francisco Bay estuary

    Science.gov (United States)

    Machak, C.; Francis, C. A.

    2013-12-01

    San Francisco Bay (SFB) estuary is the largest estuary on the western coast of the United States, draining a watershed covering more than one third of the state of California. Mercury (Hg) contamination in SFB, as a result of gold and mercury mining in the Coast Range and Sierra Nevada region, has been observed for at least 150 years. Additional sources of Hg contamination to SFB come from active oil refineries, manufacturing, and wastewater treatment plants in the area. Concentrations of methylmercury in the sediment at the time of sample collection for the present study ranged from 0.011-3.88 μg/kg (dry weight). At some sites, the concentration exceeds wetland toxicity limits, posing a threat to the health of the ecosystem and potentially endangering humans that use the estuary for food and recreation. This study attempts to understand the factors that control the transformation of Hg to methylmercury by microorganisms in aquatic sediments, where the majority of Hg methylation is known to occur. Under anoxic conditions, some sulfate- and iron-reducing bacteria have the capacity to transform Hg into methylmercury. To better understand the microbial communities involved in Hg methylation, an extensive library of 16S rRNA sequences was generated (via Illumina sequencing) from sediment samples at 20 sites throughout the SFB estuary. In addition to genomic data, we have access to a massive database of geochemical measurements made by the SFB Regional Monitoring Program at the sampling locations. These measurements show that our sediment samples have varying methylmercury concentrations and span gradients in porewater sulfate and Fe(III), which are the two known alternative electron acceptors for mercury-methylating anaerobic bacteria. The sampling sites also span gradients in other geochemical factors known to influence microbial community composition (and potentially Hg mercury methylation), such as available organic carbon, pH, and salinity. We will present the

  6. Modeling the Joint Labor-Commute Engagement Decisions of San Francisco Bay Area Residents

    OpenAIRE

    Ory, David T; Mokhtarian, Patricia L

    2005-01-01

    Using socio-demographic, personality, and attitudinal data from 1,680 residents of the San Francisco Bay Area, we develop and estimate binary, multinomial, and nested logit models of the choice to work or not, whether or not to work at home, and whether to commute all of the time or some of the time (either by only working part time, or by working a compressed work week, or by telecommuting some of the time). To our knowledge, these are the first models of all these choices simultaneously. Th...

  7. 77 FR 14349 - Availability of Report: California Eelgrass Mitigation Policy

    Science.gov (United States)

    2012-03-09

    ... potentially increasing degradation and loss from climate change, highlights the need to protect, maintain, and... entrance), San Francisco Bay, and northern California (San Francisco Bay to the California/Oregon border... manipulation of the environment has permanently altered site suitability for eelgrass or a change in...

  8. Past leaded gasoline emissions as a nonpoint source tracer in riparian systems: A study of river inputs to San Francisco Bay

    Science.gov (United States)

    Dunlap, C.E.; Bouse, R.; Flegal, A.R.

    2000-01-01

    Variations in the isotopic composition of lead in 1995-1998 river waters flowing into San Francisco Bay trace the washout of lead deposited in the drainage basin from leaded gasoline combustion. At the confluence of the Sacramento and San Joaquin rivers where they enter the Bay, the isotopic compositions of lead in the waters define a linear trend away from the measured historical compositions of leaded gas in California. The river waters are shifted away from leaded gasoline values and toward an isotopic composition similar to Sierra Nevadan inputs which became the predominant source of sedimentation in San Francisco Bay following the onset of hydraulic gold mining in 1853. Using lead isotopic compositions of hydraulic mine sediments and average leaded gasoline as mixing end members, we calculate that more than 50% of the lead in the present river water originated from leaded gasoline combustion. The strong adsorption of lead (log K(d) > 7.4) to particulates appears to limit the flushing of gasoline lead from the drainage basin, and the removal of that lead from the system may have reached an asymptotic limit. Consequently, gasoline lead isotopes should prove to be a useful nonpoint source tracer of the environmental distribution of particle- reactive anthropogenic metals in freshwater systems.

  9. Health, Traffic, and Environmental Justice: Collaborative Research and Community Action in San Francisco, California

    Science.gov (United States)

    Sciammas, Charlie; Seto, Edmund; Bhatia, Rajiv; Rivard, Tom

    2009-01-01

    Health impacts on neighborhood residents from transportation systems can be an environmental justice issue. To assess the effects of transportation planning decisions, including the construction of an intraurban freeway, on residents of the Excelsior neighborhood in southeast San Francisco, PODER (People Organizing to Demand Environmental and Economic Rights), a local grassroots environmental justice organization; the San Francisco Department of Public Health; and the University of California, Berkeley, collaborated on participatory research. We used our findings regarding traffic-related exposures and health hazards in the area to facilitate community education and action to address transportation-related health burdens on neighborhood residents. PMID:19890147

  10. Ionic strength and DOC determinations from various freshwater sources to the San Francisco Bay

    Science.gov (United States)

    Hunter, Y.R.; Kuwabara, J.S.

    1994-01-01

    An exact estimation of dissolved organic carbon (DOC) within the salinity gradient of zinc and copper metals is significant in understanding the limit to which DOC could influence metal speciation. A low-temperature persulfate/oxygen/ultraviolet wet oxidation procedure was utilized for analyzing DOC samples adapted for ionic strength from major freshwater sources of the northern and southern regions of San Francisco Bay. The ionic strength of samples was modified with a chemically defined seawater medium up to 0.7M. Based on the results, a minimum effect of ionic strength on oxidation proficiency for DOC sources to the Bay over an ionic strength gradient of 0.0 to 0.7 M was observed. There was no major impacts of ionic strength on two Suwanee River fulvic acids. In general, the noted effects associated with ionic strength were smaller than the variances seen in the aquatic environment between high- and low-temperature methods.

  11. Geology and geomorphology--Drakes Bay and Vicinity Bay Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the geologic and geomorphic map of the Drakes Bay and Vicinity map area, California. The polygon shapefile is included in...

  12. Geology and geomorphology--Drakes Bay and Vicinity Bay Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the geologic and geomorphic map of the Drakes Bay and Vicinity map area, California. The polygon shapefile is included in...

  13. Wastewater effluent dispersal in Southern California Bays

    KAUST Repository

    Uchiyama, Yusuke

    2014-03-01

    The dispersal and dilution of urban wastewater effluents from offshore, subsurface outfalls is simulated with a comprehensive circulation model with downscaling in nested grid configurations for San Pedro and Santa Monica Bays in Southern California during Fall of 2006. The circulation is comprised of mean persistent currents, mesoscale and submesoscale eddies, and tides. Effluent volume inflow rates at Huntington Beach and Hyperion are specified, and both their present outfall locations and alternative nearshore diversion sites are assessed. The effluent tracer concentration fields are highly intermittent mainly due to eddy currents, and their probability distribution functions have long tails of high concentration. The dilution rate is controlled by submesoscale stirring and straining in tracer filaments. The dominant dispersal pattern is alongshore in both directions, approximately along isobaths, over distances of more than 10. km before dilution takes over. The current outfall locations mostly keep the effluent below the surface and away from the shore, as intended, but the nearshore diversions do not. © 2014 Elsevier Ltd.

  14. Marine magnetic survey and onshore gravity and magnetic survey, San Pablo Bay, northern California

    Science.gov (United States)

    Ponce, David A.; Denton, Kevin M.; Watt, Janet T.

    2016-09-12

    IntroductionFrom November 2011 to August 2015, the U.S. Geological Survey (USGS) collected more than 1,000 line-kilometers (length of lines surveyed in kilometers) of marine magnetic data on San Pablo Bay, 98 onshore gravity stations, and over 27 line-kilometers of ground magnetic data in northern California. Combined magnetic and gravity investigations were undertaken to study subsurface geologic structures as an aid in understanding the geologic framework and earthquake hazard potential in the San Francisco Bay Area. Furthermore, marine magnetic data illuminate local subsurface geologic features in the shallow crust beneath San Pablo Bay where geologic exposure is absent.Magnetic and gravity methods, which reflect contrasting physical properties of the subsurface, are ideal for studying San Pablo Bay. Exposed rock units surrounding San Pablo Bay consist mainly of Jurassic Coast Range ophiolite, Great Valley sequence, Franciscan Complex rocks, Miocene sedimentary rocks, and unconsolidated alluvium (Graymer and others, 2006). The contrasting magnetic and density properties of these rocks enable us to map their subsurface extent.

  15. San Francisco Bay, California Coastal Digital Elevation Model

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA's National Geophysical Data Center (NGDC) is building high-resolution digital elevation models (DEMs) for select U.S. coastal regions. These integrated...

  16. Shallow benthic habitats of San Francisco Bay, California CMECS Geodatabase

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has been developed for the National Oceanic and Atmospheric Administration's (NOAA) Office for Coastal Management (OCM) as a collaborative and...

  17. Biological communities in San Francisco Bay track large-scale climate forcing over the North Pacific

    Science.gov (United States)

    Cloern, James E.; Hieb, Kathryn A.; Jacobson, Teresa; Sansó, Bruno; Di Lorenzo, Emanuele; Stacey, Mark T.; Largier, John L.; Meiring, Wendy; Peterson, William T.; Powell, Thomas M.; Winder, Monika; Jassby, Alan D.

    2010-11-01

    Long-term observations show that fish and plankton populations in the ocean fluctuate in synchrony with large-scale climate patterns, but similar evidence is lacking for estuaries because of shorter observational records. Marine fish and invertebrates have been sampled in San Francisco Bay since 1980 and exhibit large, unexplained population changes including record-high abundances of common species after 1999. Our analysis shows that populations of demersal fish, crabs and shrimp covary with the Pacific Decadal Oscillation (PDO) and North Pacific Gyre Oscillation (NPGO), both of which reversed signs in 1999. A time series model forced by the atmospheric driver of NPGO accounts for two-thirds of the variability in the first principal component of species abundances, and generalized linear models forced by PDO and NPGO account for most of the annual variability of individual species. We infer that synchronous shifts in climate patterns and community variability in San Francisco Bay are related to changes in oceanic wind forcing that modify coastal currents, upwelling intensity, surface temperature, and their influence on recruitment of marine species that utilize estuaries as nursery habitat. Ecological forecasts of estuarine responses to climate change must therefore consider how altered patterns of atmospheric forcing across ocean basins influence coastal oceanography as well as watershed hydrology.

  18. Empirical model of Skeletonema costatum photosynthetic rate, with applications in the San Francisco Bay estuary

    Science.gov (United States)

    Cloern, J.E.

    1978-01-01

    An empirical model of Skeletonema costatum photosynthetic rate is developed and fit to measurements of photosynthesis selected from the literature. Because the model acknowledges existence of: 1) a light-temperature interaction (by allowing optimum irradiance to vary with temperature), 2) light inhibition, 3) temperature inhibition, and 4) a salinity effect, it accurately estimates photosynthetic rates measured over a wide range of temperature, light intensity, and salinity. Integration of predicted instantaneous rate of photosynthesis with time and depth yields daily net carbon assimilation (pg C cell-1 day-1) in a mixed layer of specified depth, when salinity, temperature, daily irradiance and extinction coefficient are known. The assumption of constant carbon quota (pg C cell-1) allows for prediction of mean specific growth rate (day-1), which can be used in numerical models of Skeletonema costatum population dynamics. Application of the model to northern San Francisco Bay clearly demonstrates the limitation of growth by low light availability, and suggests that large population densities of S. costatum observed during summer months are not the result of active growth in the central deep channels (where growth rates are consistently predicted to be negative). But predicted growth rates in the lateral shallows are positive during summer and fall, thus offering a testable hypothesis that shoals are the only sites of active population growth by S. costatum (and perhaps other neritic diatoms) in the northern reach of San Francisco Bay. ?? 1978.

  19. Final report for sea-level rise response modeling for San Francisco Bay estuary tidal marshes

    Science.gov (United States)

    Takekawa, John Y.; Thorne, Karen M.; Buffington, Kevin J.; Spragens, Kyle A.; Swanson, Kathleen M.; Drexler, Judith Z.; Schoellhamer, David H.; Overton, Cory T.; Casazza, Michael L.

    2013-01-01

    The International Panel on Climate Change has identified coastal ecosystems as areas that will be disproportionally affected by climate change. Current sea-level rise projections range widely with 0.57 to 1.9 meters increase in mea sea level by 2100. The expected accelerated rate of sea-level rise through the 21st century will put many coastal ecosystems at risk, especially those in topographically low-gradient areas. We assessed marsh accretion and plant community state changes through 2100 at 12 tidal salt marshes around San Francisco Bay estuary with a sea-level rise response model. Detailed ground elevation, vegetation, and water level data were collected at all sites between 2008 and 2011 and used as model inputs. Sediment cores (taken by Callaway and others, 2012) at four sites around San Francisco Bay estuary were used to estimate accretion rates. A modification of the Callaway and others (1996) model, the Wetland Accretion Rate Model for Ecosystem Resilience (WARMER), was utilized to run sea-level rise response models for all sites. With a mean sea level rise of 1.24 m by 2100, WARMER projected that the vast majority, 95.8 percent (1,942 hectares), of marsh area in our study will lose marsh plant communities by 2100 and to transition to a relative elevation range consistent with mudflat habitat. Three marshes were projected to maintain marsh vegetation to 2100, but they only composed 4.2 percent (85 hectares) of the total marsh area surveyed.

  20. In-situ measurements of seismic velocities in the San Francisco Bay region...part II

    Science.gov (United States)

    Gibbs, James F.; Fumal, Thomas E.; Borcherdt, Roger D.

    1976-01-01

    Seismic wave velocities (compressional and shear) are important parameters for determining the seismic response characteristics of various geologic units when subjected to strong earthquake ground shaking. Seismic velocities of various units often show a strong correlation with the amounts of damage following large earthquakes and have been used as a basis for certain types of seismic zonation studies. Currently a program is in progress to measure seismic velocities in the San Francisco Bay region at an estimated 150 sites. At each site seismic travel times are measured in drill holes, normally at 2.5-m intervals to a depth of 30 m. Geologic logs are determined from drill hole cuttings, undisturbed samples, and penetrometer samples. The data provide a detailed comparison of geologic and seismic characteristics and provide parameters for estimating strong earthquake ground motions quantitatively at each of the site. A major emphasis of this program is to obtain a detailed comparison of geologic and seismic data on a regional scale for use in seismic zonation. The broad data base available in the San Francisco Bay region suggests using the area as a pilot area for the development of general techniques applicable to other areas.

  1. Heavy mineral analysis for assessing the provenance of sandy sediment in the San Francisco Bay Coastal System

    Science.gov (United States)

    Wong, F. L.; Woodrow, D. L.; McGann, M. L.

    2012-12-01

    Heavy minerals have been used to trace the sources and transportation of sandy sediment in San Francisco Bay and nearby coastal areas since the 1960s. We have the opportunity to sample similar environments and revisit the heavy mineral populations under the current San Francisco Coastal System study of the provenance of beach sand. Most of the sandy sediment in San Francisco Bay can be traced to distant sources including the Sierra Nevada batholith and associated terranes with local contributions from the Franciscan Complex. Heavy minerals from Sierran sources include ordinary hornblende, metamorphic amphiboles, and hypersthene while those from the Franciscan Complex include other types of pyroxene, epidote, basaltic hornblende, and glaucophane... Tertiary strata and volcanics in the surrounding hills and displaced Sierran rocks found on the continental shelf west of the San Andreas Fault Zone introduce similar minerals, but perhaps in a lesser volume to be identified as major contributors... The primary result of cluster analysis of heavy minerals separated from sand-sized sediment taken within San Francisco Bay, the adjacent continental shelf, local beaches, cliffs outside the Golden Gate, and upstream drainages indicate a widespread occurrence of sediment traceable to the Sierra Nevada. A second cluster of samples identifies samples of mixed Sierran and Franciscan lineage within the strait of the Golden Gate, on the San Francisco bar, and on coastal beaches. Sediment samples with predominantly Franciscan mineral content appear on beaches around Point Reyes, possibly transported from the Russian River. The heavy mineral composition supports transport from the east, through San Francisco Bay and out the Golden Gate to the San Francisco bar and southward.

  2. Sub-tidal benthic habitats of central San Francisco Bay and offshore Golden Gate area: a review

    Science.gov (United States)

    Greene, H. Gary; Endris, Charles; Vallier, Tracy; Golden, Nadine E.; Cross, Jeffery; Ryan, Holly F.; Dieter, Bryan; Niven, Eric; Barnard, P.L.; Jaffee, B.E.; Schoellhamer, D.H.

    2013-01-01

    Deep-water potential estuarine and marine benthic habitat types were defined from a variety of new and interpreted data sets in central San Francisco Bay and offshore Golden Gate area including multibeam echosounder (MBES), side-scan sonar and bottom grab samples. Potential estuarine benthic habitats identified for the first time range from hard bedrock outcrops on island and mainland flanks and some Bay floor

  3. The Performance of Nearshore Dredge Disposal at Ocean Beach, San Francisco, California, 2005-2007

    Science.gov (United States)

    Barnard, Patrick L.; Erikson, Li H.; Hansen, Jeff E.; Elias, Edwin

    2009-01-01

    Ocean Beach, California, contains an erosion hot spot in the shadow of the San Francisco ebb tidal delta that threatens valuable public infrastructure as well as the safe recreational use of the beach. In an effort to reduce the erosion at this location a new plan for the management of sediment dredged annually from the main shipping channel at the mouth of San Francisco Bay was implemented in May 2005 by the United States Army Corps of Engineers, San Francisco District (USACE). The USACE designated a temporary nearshore dredge disposal site for the annual disposal of about 230,000 m3 (300,000 yd3) of sand about 750 m offshore and slightly south of the erosion hot spot, in depths between approximately 9 and 14 m. The site has now been used three times for a total sediment disposal of about 690,000 m3 (about 900,000 yds3). The disposal site was chosen because it is in a location where strong tidal currents and open-ocean waves can potentially feed sediment toward the littoral zone in the reach of the beach that is experiencing critical erosion, as well as prevent further scour on an exposed outfall pipe. The onshore migration of sediment from the target disposal location might feed the primary longshore bar or the nearshore zone, and provide a buffer to erosion that peaks during winter months when large waves impact the region. The United States Geological Survey (USGS) has been monitoring and modeling the bathymetric evolution of the test dredge disposal site and the adjacent coastal region since inception in May 2005. This paper reports on the first 2.5 years of this monitoring program effort (May 2005 to December 2007) and assesses the short-term coastal response. Here are the key findings of this report: *Approximately half of the sediment that has been placed in the nearshore dredge-disposal site during the 2.5 years of this study remains within the dredge focus area. *In the winter of 2006-7, large waves transported the dredge-mound material onshore. *High

  4. Liminalidad social y negociación cultural: inmigrantes yucatecos en San Francisco, California

    Directory of Open Access Journals (Sweden)

    Inés Cornejo-Portugal

    2012-01-01

    Full Text Available Mediante los conceptos de liminalidad social y negociación cultural analizamos tres estudios de caso de yucatecos migrantes en San Francisco, California. Los migrantes estudiados dan cuenta de las diversas formas como utilizan los recursos sociales a los cuales tienen acceso (familiares, de creencia, de amistad y vecinales y que les permiten encontrar un equilibrio emocional relativo, frente a la tensión cultural de la sociedad destino.

  5. Near-surface wind fields for San Francisco Bay--historical and 21st century projected time series

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — To support Coastal Storm Modeling System (CoSMoS) in the San Francisco Bay (v2.1), time series of historical and 21st-century near-surface wind fields (eastward and...

  6. 33 CFR 100.1105 - San Francisco Bay Navy Fleetweek Parade of Ships and Blue Angels Demonstration.

    Science.gov (United States)

    2010-07-01

    ... Parade of Ships and Blue Angels Demonstration. 100.1105 Section 100.1105 Navigation and Navigable Waters... WATERS § 100.1105 San Francisco Bay Navy Fleetweek Parade of Ships and Blue Angels Demonstration. (a... Navy Ships and Navy Blue Angels and other airshow activities held annually in early October,...

  7. Chronic sublethal effects of San Francisco Bay sediments on nereis (neanthes) arenaceodentata; bioaccumulation from bedded sediments. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Moore, D.; Dillon, T.M.

    1993-09-01

    In previous studies with San Francisco Bay sediments, minimal chronic sublethal effects were detected (Miscellaneous Paper D-93-1 and another Miscellaneous Paper in preparation by Moore and Dillon). To ensure that the lack of effects was not due to a lack of contaminant uptake, a bioaccumulation experiment was conducted. Bioaccumulation from bedded sediments was evaluated following a 9-week exposure with the marine polychaete worm Nereis (Neanthes) arenaceodentata. Two sediments were evaluated, a contaminated San Francisco Bay test sediment and a clean control sediment from Sequim, WA. Animals were exposed as early juveniles through adulthood. Tissues were analyzed for metals, polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and pesticides. Worms exposed to the contaminated San Francisco Bay sediment had significantly higher tissue residues of silver (0.30 mg/kg dry weight) and tributyltin (0.298 mg/kg dry weight). Conversely, tissue residues of control animals were significantly higher in cadmium (0.67 mg/kg dry weight) and lead (1.89 mg/kg dry weight). Small Amounts (0.02 mg/kg dry weight) of aldrin and dieldrin were measured in worms exposed to the contaminated sediment, while dieldrin and 8-BHC were found in Bioaccumulation, Neanthes, Chronic sublethal, San Francisco Bay, Dredged, Material, Sediment.

  8. Francisco Drake toma posesión de la California Española

    Directory of Open Access Journals (Sweden)

    Juan Friede

    1981-01-01

    Full Text Available Entre los documentos de la Universidad de California, en Berkeley, se encuentra una placa de bronce que evoca el nombre del navegante que jugó un papel descollante en la historia de toda la America. Se trata del acta de la "toma de posesión" que el 17 de junio de 1579 hiciera de California en la costa del Pacífico, el famoso -y notorio- corsario Francisco Drake, conocido en la historia de la colonia por su ataque a Cartagena.

  9. Smart Parking Linked to Transit: Lessons Learned from the San Francisco Bay Area Field Test

    OpenAIRE

    Shaheen, Susan; Kemmerer, Charlene

    2007-01-01

    Rising demand for parking at suburban transit stations, such as the Bay Area Rapid Transit (BART) District in California, necessitates strategies to manage traveler demand. To better manage parking supply, researchers implemented a smart parking field test at the Rockridge BART station from 2004 to 2006 to evaluate the effects of smart parking technologies (changeable message signs (CMSs), Internet reservations and billing, mobile phone and personal digital assistant communications, and a wir...

  10. Avian communities in baylands and artificial salt evaporation ponds of the San Francisco Bay estuary

    Science.gov (United States)

    Takekawa, J.Y.; Lu, C.T.; Pratt, R.T.

    2001-01-01

    San Francisco Bay wetlands, seasonal and tidal marshes between the historic low and high tide lines, are now highly fragmented because of development during the past 150 years. Artificial salt pond systems in the Bay are hypersaline and typically support simple assemblages of algae and invertebrates. In order to establish the value of salt ponds for migratory waterbirds, we used datasets to conduct a meta-analysis of avian communities in the baylands and salt ponds of San Pablo Bay. Fifty-three species of waterbirds in the salt ponds represented six foraging guilds: surface feeders, shallow probers, deep probers, dabblers, diving benthivores and piscivores. The total number of species and the Shannon-Weiner diversity index was higher in baylands than in salt ponds during all four seasons. However, overall bird density (number/ha) was higher in salt ponds compared with baylands in the winter and spring, primarily because of large concentrations of benthivores. Cessation of salt production in 1993 and subsequent reduction in water depth resulted in a decline of some diving duck populations that used the salt ponds.

  11. Bedrock knobs, San Francisco Bay: Do navigation hazards outweigh other environment problems?

    Science.gov (United States)

    Carlson, P.R.; Chin, J.L.; Wong, F.L.

    2000-01-01

    Three bedrock knobs (Arch, Harding, and Shag rocks) rise above the unconsolidated sediment of central San Francisco Bay to a water depth of less than -12 m (cities of the Bay estuary. Acoustic profiling data show that bedrock extends at a gentle to moderate slope away from the knobs. These data also show that two of the knobs, Harding and Shag, may be part of a bedrock ridge that extends to Alcatraz Island and perhaps southeast to Blossom Rock. The tops of these rocks should be lowered to a depth of -17 m (-55.8 ft), with a total volume of as much as 245,000 m3 (320,460 yd3), at an estimated cost of nearly 27 million dollars, to eliminate the possibility that a tanker would strike one and rupture. A resulting large oil spill would likely cost many times more than the 10 million dollars needed to clean up a small 1996 spill. If the rocks were removed, local habitat for striped bass and other game fish would be altered, with potential negative impact on sport fishing. Currently, public officials are studying the benefits to the Bay environment of lowering the rock knobs.

  12. Space Geodetic Imaging of Earthquake Potential in the San Francisco Bay Area

    Science.gov (United States)

    Bürgmann, R.; Funning, G. J.; Ferretti, A.; Novali, F.

    2008-12-01

    Active crustal deformation in the San Francisco Bay Area includes contributions from elastic strain buildup across major faults and aseismic fault creep relieving a small portion of the plate tectonic fault slip budget. Increasingly precise and dense measurements of surface motions using GPS and InSAR satellite data provide valuable information on the distribution and rates of surface deformation. In the Eastern Bay Area, the Hayward, Calaveras and Concord faults are known to be source areas of moderate to large earthquakes, but also exhibit significant aseismic fault creep. Modeling of space geodetic data collected along the Hayward fault over > 10-year period allows for the determination of the distribution of currently locked asperities and creeping portions of the fault zone. Inversions of these data reveal a locked zone at depth which has built up a slip deficit since the 1868 Hayward fault rupture that is large enough to produce a M > 6.7 earthquake. The inferred slip rates along the creeping portions of the Hayward fault are significantly less than the long-term slip rate, and thus a substantial slip deficit is accumulating there as well. However, it is possible that the creeping portions of the East Bay faults will catch up most of their slip deficit by accelerated postseismic creep following large ruptures of the currently locked asperities. The kinematic locking models help inform dynamic rupture scenarios and ground motion simulations of major earthquakes along the Hayward fault (Aagaard et al., 2008 Fall AGU).

  13. Results of bulk sediment analysis and bioassay testing on selected sediments from Oakland Inner Harbor and Alcatraz disposal site, San Francisco, California

    Energy Technology Data Exchange (ETDEWEB)

    Word, J Q; Ward, J A; Woodruff, D L

    1990-09-01

    The Battelle/Marine Sciences Laboratory (MSL) was contracted by the US Army Corps of Engineers, San Francisco District, to perform bulk sediment analysis and oyster larvae bioassays (elutriate) on sediments from Inner Oakland Harbor, California. Analysis of sediment characteristics by MSL indicated elevated priority pollutants, PAHs, pesticides, metals, organotins, and oil and grease concentrations, when compared to Alcatraz Island Dredged Material Disposal Site sediment concentrations. Larvae of the Pacific oyster, Crassostrea gigas, were exposed to seawater collected from the Alcatraz Island Site water, and a series of controls using water and sediments collected from Sequim Bay, Washington. Exposure of larvae to the Alcatraz seawater and the 50% and 100% elutriate concentrations from each Oakland sediment resulted in low survival and a high proportion of abnormal larvae compared to Sequim Bay control exposures. MSL identified that field sample collection, preservation, and storage protocols used by Port of Oakland contractors were inconsistent with standard accepted practices. 23 refs., 10 figs., 40 tabs.

  14. Estimating methane emissions from biological and fossil-fuel sources in the San Francisco Bay Area

    Science.gov (United States)

    Jeong, Seongeun; Cui, Xinguang; Blake, Donald R.; Miller, Ben; Montzka, Stephen A.; Andrews, Arlyn; Guha, Abhinav; Martien, Philip; Bambha, Ray P.; LaFranchi, Brian; Michelsen, Hope A.; Clements, Craig B.; Glaize, Pierre; Fischer, Marc L.

    2017-01-01

    We present the first sector-specific analysis of methane (CH4) emissions from the San Francisco Bay Area (SFBA) using CH4 and volatile organic compound (VOC) measurements from six sites during September - December 2015. We apply a hierarchical Bayesian inversion to separate the biological from fossil-fuel (natural gas and petroleum) sources using the measurements of CH4 and selected VOCs, a source-specific 1 km CH4 emission model, and an atmospheric transport model. We estimate that SFBA CH4 emissions are 166-289 Gg CH4/yr (at 95% confidence), 1.3-2.3 times higher than a recent inventory with much of the underestimation from landfill. Including the VOCs, 82 ± 27% of total posterior median CH4 emissions are biological and 17 ± 3% fossil fuel, where landfill and natural gas dominate the biological and fossil-fuel CH4 of prior emissions, respectively.

  15. Assessing vulnerable and expanding vegetation stands and species in the San Francisco Bay Area for conservation management under climate change

    Science.gov (United States)

    Morueta-Holme, N.; Heller, N. E.; McLaughlin, B.; Weiss, S. B.; Ackerly, D.

    2015-12-01

    The distribution of suitable climatic areas for species and vegetation types is expected to shift due to ongoing climate change. While the pace at which current distributions will shift is hard to quantify, predictions of where climatically suitable areas will be in the future can allow us to map 1) areas currently occupied by a species or vegetation type unlikely to persist through the end of this century (vulnerable stands), 2) areas likely to do better in the future and serve as nuclei for population expansion (expanding stands), and 3) areas likely to act as climate refugia (persisting stands). We quantified the vulnerability of 27 individual plant species and 27 vegetation types in the San Francisco Bay Area as well as the conservation importance, vulnerability, and resilience of selected management sites for climate change resilient conservation. To this end, we developed California-wide models of species and vegetation distributions using climate data from the 2014 California Basin Characterization Model at a 270 m resolution, projected to 18 different end-of century climate change scenarios. Combining these distribution models with high resolution maps of current vegetation, we were able to map projected vulnerable, expanding, and persisting stands within the Bay Area. We show that vegetation and species are expected to shift considerably within the study region over the next decades; although we also identify refugia potentially able to offset some of the negative impacts of climate change. We discuss the implications for managers that wish to incorporate climate change in conservation decisions, in particular related to choosing species for restoration, identifying areas to collect seeds for restoration, and preparing for expected major vegetation changes. Our evaluation of individual management sites highlights the need for stronger coordination of efforts across sites to prioritize monitoring and protection of species whose ranges are contracting

  16. Drivers of change in estuarine-coastal ecosystems: Discoveries from four decades of study in San Francisco Bay

    Science.gov (United States)

    Cloern, J.E.; Jassby, A.D.

    2012-01-01

    Poised at the interface of rivers, ocean, atmosphere and dense human settlement, estuaries are driven by a large array of natural and anthropogenic forces. San Francisco Bay exemplifies the fast-paced change occurring in many of the world's estuaries, bays and inland seas in response to these diverse forces. We use observations from this particularly well-studied estuary to illustrate responses to six drivers that are common agents of change where land and sea meet: water consumption and diversion; human modification of sediment supply; introduction of non-native species; sewage input; environmental policy; and climate shifts. In San Francisco Bay, responses to these drivers include, respectively, shifts in the timing and extent of freshwater inflow and salinity intrusion; decreasing turbidity; restructuring of plankton communities; nutrient enrichment; elimination of hypoxia and reduced metal contamination of biota; and food web changes that decrease resistance of the estuary to nutrient pollution. Detection of these changes and discovery of their causes through environmental monitoring have been essential for establishing and measuring outcomes of environmental policies that aim to maintain high water quality and sustain services provided by estuarine-coastal ecosystems. The wide range of variability time scales and the multiplicity of interacting drivers place heavy demands on estuarine monitoring programs. But the San Francisco Bay case study illustrates why the imperative for monitoring has never been greater.

  17. Drivers of change in estuarine-coastal ecosystems: Discoveries from four decades of study in San Francisco Bay

    Science.gov (United States)

    Cloern, James E.; Jassby, Alan D.

    2012-12-01

    Poised at the interface of rivers, ocean, atmosphere and dense human settlement, estuaries are driven by a large array of natural and anthropogenic forces. San Francisco Bay exemplifies the fast-paced change occurring in many of the world's estuaries, bays, and inland seas in response to these diverse forces. We use observations from this particularly well-studied estuary to illustrate responses to six drivers that are common agents of change where land and sea meet: water consumption and diversion, human modification of sediment supply, introduction of nonnative species, sewage input, environmental policy, and climate shifts. In San Francisco Bay, responses to these drivers include, respectively, shifts in the timing and extent of freshwater inflow and salinity intrusion, decreasing turbidity, restructuring of plankton communities, nutrient enrichment, elimination of hypoxia and reduced metal contamination of biota, and food web changes that decrease resistance of the estuary to nutrient pollution. Detection of these changes and discovery of their causes through environmental monitoring have been essential for establishing and measuring outcomes of environmental policies that aim to maintain high water quality and sustain services provided by estuarine-coastal ecosystems. The many time scales of variability and the multiplicity of interacting drivers place heavy demands on estuarine monitoring programs, but the San Francisco Bay case study illustrates why the imperative for monitoring has never been greater.

  18. Microbial Mercury Cycling in San Francisco Bay Sediments: From Regions to the Rhizosphere

    Science.gov (United States)

    Evans, V. A.; Mann, A.; Romeis, J.; Marvin-Dipasquale, M. C.; Agee, J. L.; Kieu, L. H.; Harms, H. A.

    2004-05-01

    The San Francisco Bay (SFB) estuary is hydrodynamically diverse ecosystem with extensive mercury contamination associated with historic gold and mercury mining wastes, and in a region with an unprecedented number of wetland restoration projects planned or ongoing. Wetlands are known to be active areas for the microbial transformation of Hg(II) to methylmercury (MeHg), which bioaccumulates in the food web. A better understanding of this microbial process, in these restored wetlands and other sub-habitats, is critical if Hg contamination is to be successfully managed in this system. An examination of MeHg production and degradation in sediments has been conducted at multiple spatial scales throughout the SFB estuary and its tributaries over the past four years. At the regional scale, we will present data from the brackish Bay, the delta, and rivers and reservoirs in tributary watersheds. Within the freshwater delta and river regions, a new project is focusing on emergent marsh, non-vegetated open water, and submerged-macrophyte zones. At the smallest scale, we consider microbial Hg cycling in the root zone (rhizosphere) of dominant wetland plants and propose a conceptual model of the key biogoechemical reactions that may make this transitional zone one of the most important with respect to Hg(II)-methylation.

  19. Amendment to refuge hunting plan for waterfowl on 5,500 acres of former commercial salt ponds : Don Edwards San Francisco Bay NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This amendment to the 1982 Don Edwards San Francisco Bay NWR waterfowl hunting plan was written to address 5,500 acres of salt pond recently acquisitioned by the...

  20. Wed. May 13, Hayward, Calif. -- EPA Administrator McCarthy joins San Francisco Bay Area agencies to celebrate nations largest solar energy partnership

    Science.gov (United States)

    SAN FRANCISCO - On Wednesday, May 13, U.S. EPA Administrator Gina McCarthy will join Bay Area agencies to celebrate the nation's largest local government collaborative for solar power and launch the nation's first federal solar partnership. Administ

  1. Establishing baseline conditions to inform adaptive management of South San Francisco Bay salt ponds: A comparison of waterbird abundance from the 1980s to the 2000s

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The 30,000 acres of wetlands within the Don Edwards San Francisco Bay National Wildlife Refuge (Refuge) provide critical habitat for over one million waterbirds...

  2. Transportation impacts to wildlife on state route 37 in northern San Pablo Bay, California

    Science.gov (United States)

    Winton, Bryan R.; Takekawa, John Y.

    2002-01-01

    State Route 37 bisects conservation lands managed by San Pablo Bay National Wildlife Refuge (U.S. Fish & Wildlife Service) and Napa-Sonoma Marshes Wildlife Area (California Department of Fish and Game) in Solano and Sonoma Counties. The 2-lane highway connects Interstates 101 and 80 in northern San Francisco Bay and experiences ~26,000 vehicles per day. Road-killed wildlife between Napa River and Tolay Creek bridges (14.7 km) were counted in 2000 to ascertain species composition, relative abundance, and relative occurence (animal fatality interval). The primary objectives of the study were to determine if endangered salt marsh harvest mice (Reithrodontomys raviventris), California clapper rails (Rallus longirostris), or other species of concern were represented, and to collect baseline data on transportation impacts to wildlife in the area. During 51 surveys, 291 dead birds (54.6%) and mammals (45.4%) were observed. Endangered species were not positively identified dead on the highway. In total, 28 bird, 10 mammal and 1 reptile species were positively identified along this section of highway that traverses tidal marsh and diked baylands (i.e., salt ponds, seasonal wetlands, and oat-hay agriculture fields). The mean animal fatality interval for both lanes was one road-kill every 2.1km (2.1 km SD).

  3. 2010 bathymetric survey and digital elevation model of Corte Madera Bay, California

    Science.gov (United States)

    Foxgrover, Amy C.; Finlayson, David P.; Jaffe, Bruce E.; Takekawa, John Y.; Thorne, Karen M.; Spragens, Kyle A.

    2011-01-01

    A high-resolution bathymetric survey of Corte Madera Bay, California, was collected in early 2010 in support of a collaborative research project initiated by the San Francisco Bay Conservation and Development Commission and funded by the U.S. Environmental Protection Agency. The primary objective of the Innovative Wetland Adaptation in the Lower Corte Madera Creek Watershed Project is to develop shoreline adaptation strategies to future sea-level rise based upon sound science. Fundamental to this research was the development of an of an up-to-date, high-resolution digital elevation model (DEM) extending from the subtidal environment through the surrounding intertidal marsh. We provide bathymetric data collected by the U.S. Geological Survey and have merged the bathymetry with a 1-m resolution aerial lidar data set that was collected by the National Oceanic and Atmospheric Administration during the same time period to create a seamless, high-resolution DEM of Corte Madera Bay and the surrounding topography. The bathymetric and DEM surfaces are provided at both 1 m and 10 m resolutions formatted as both X, Y, Z text files and ESRI Arc ASCII files, which are accompanied by Federal Geographic Data Committee compliant metadata.

  4. Mercury Isotopic Composition of Young-of-Year Fish in San Francisco Bay

    Science.gov (United States)

    Gehrke, G. E.; Blum, J. D.; Slotton, D. G.; Greenfield, B. K.

    2009-12-01

    Variations in the stable isotopic composition of mercury (Hg) can provide information about sources and biogeochemical transformations of Hg in the environment. Mass-dependent fractionation of Hg isotopes, reported as δ202Hg relative to NIST 3133, has been observed during multiple processes including volatilization, diffusion, reduction and de-methylation. Large mass-independent fractionation of Hg (>0.2‰) reported as Δ199Hg, has been observed only during photochemical reduction of Hg and MeHg. In this study we analyzed the Hg isotopic composition of sediments and young (South and Lower South Bay (+0.10 to +0.60‰), San Pablo Bay (-0.25 to -0.03‰), and Suisun Bay (+0.13 to +0.42‰). Fish δ202Hg values roughly correlate with sediment δ202Hg values from the same sites. We suggest that each of the Guadalupe, Petaluma, and Sacaramento-San Joaquin river systems supply a distinct source of Hg to San Francisco Bay, likely associated with contaminated sediment. Mississippi silverside have Δ199Hg values ranging +0.46 to +1.55‰. Unlike the δ202Hg values, fish Δ199Hg values do not vary in a regular pattern throughout the Bay. Rather, fish from approximately one-third of sites analyzed exhibit relatively elevated Δ199Hg (> 0.8‰), possibly associated with high water clarity. In all fish analyzed, the ratio of Δ199Hg to Δ201Hg values have a narrow range of 1.19 to 1.40 (avg = 1.26 ± 0.06). These ratios in fish are consistent with laboratory studies of photochemical MeHg degradation, which yielded Δ199Hg: Δ201Hg ratios of ~1.3 (Bergquist and Blum, 2007). We suggest that Δ199Hg in fish varies with the extent of photochemical MeHg degradation prior to food web uptake. Bergquist, B. A. and Blum, J. D., 2007. Mass-dependent and -independent fractionation of Hg isotopes by photoreduction in aquatic systems. Science 318, 417-420.

  5. The role of habitat-selection in restricting invasive blue mussel advancement to protect native populations in San Francisco Bay

    Science.gov (United States)

    Mittal, N.; Saarman, N. P.; Pogson, G.

    2013-12-01

    Introduced species contribute to decline of biodiversity and ecosystem services. Introduced species threaten native species by increasing competition for space and resources, changing their habitat, and disrupting species interactions. Protecting native species is crucial to preserving ecosystem services (i.e. medicinal, agricultural, ecological, and cultural benefits) for future generations. In marine communities, the number of invasive species is dramatically increasing every year, further magnifying the negative impact on native species. This research determines if habitat-specific selection can protect native species from their invasive relatives, and could allow targeted habitat restoration for native species to maintain high levels of biodiversity. Blue mussels provide an ideal system for studying the impact of an invasive species (Mytilus galloprovincialis) on native mussels (M. trossulus), because M. galloprovincialis is marked as one of the world's 100 worst invasive species. Hybridization between M. galloprovincialis and M. trossulus occurs wherever their distributions overlap (i.e. Japan, Puget Sound, and central California). In central California, hybrids form in a broad variety of habitats ever since M. galloprovincialis was introduced about 100 years ago. The current level of threat posed to native mussels in central California is unknown. When population growth rate of an invasive species is higher than the native within a hybrid zone, the invader's genes become more prominent in the hybrids than the native species' genes. This uneven mix of genes and decrease of pure native mussels threatens to drive M. trossulus to extinction. Therefore, it is important to research which environment fosters highest success of pure native species. We conducted a field experiment in San Francisco Bay where mussels were reared in different habitats. We then collected samples and extracted DNA from each treatment, and genotyped them by a next-generation sequencing

  6. Sand sources and transport pathways for the San Francisco Bay coastal system, based on X-ray diffraction mineralogy

    Science.gov (United States)

    Hein, James R.; Mizell, Kira; Barnard, Patrick L.; Barnard, P.L.; Jaffee, B.E.; Schoellhamer, D.H.

    2013-01-01

    The mineralogical compositions of 119 samples collected from throughout the San Francisco Bay coastal system, including bayfloor and seafloor, area beaches, cliff outcrops, and major drainages, were determined using X-ray diffraction (XRD). Comparison of the mineral concentrations and application of statistical cluster analysis of XRD spectra allowed for the determination of provenances and transport pathways. The use of XRD mineral identifications provides semi-quantitative compositions needed for comparisons of beach and offshore sands with potential cliff and river sources, but the innovative cluster analysis of XRD diffraction spectra provides a unique visualization of how groups of samples within the San Francisco Bay coastal system are related so that sand-sized sediment transport pathways can be inferred. The main vector for sediment transport as defined by the XRD analysis is from San Francisco Bay to the outer coast, where the sand then accumulates on the ebb tidal delta and also moves alongshore. This mineralogical link defines a critical pathway because large volumes of sediment have been removed from the Bay over the last century via channel dredging, aggregate mining, and borrow pit mining, with comparable volumes of erosion from the ebb tidal delta over the same period, in addition to high rates of shoreline retreat along the adjacent, open-coast beaches. Therefore, while previously only a temporal relationship was established, the transport pathway defined by mineralogical and geochemical tracers support the link between anthropogenic activities in the Bay and widespread erosion outside the Bay. The XRD results also establish the regional and local importance of sediment derived from cliff erosion, as well as both proximal and distal fluvial sources. This research is an important contribution to a broader provenance study aimed at identifying the driving forces for widespread geomorphic change in a heavily urbanized coastal-estuarine system.

  7. Monitoring the Northern San Francisco Bay Water Quality with Landsat-8. Nicholas B. Tufillaroa , and Curtiss O. Davisa. aOregon State University, Corvallis, OR, 97331, USA, nbt@coas.oregonstate.edu

    Science.gov (United States)

    Davis, C. O.; Tufillaro, N.

    2016-02-01

    Landsat-8's high spatial resolution ( 30 nm nominal), improved signal-to-noise (12bit digitizer) and expanded band set open up new applications for coastal and in-land waters. We use a recent ocean color processor for Landsat-8 created by Vanhellemont and Ruddick (RSE, 2015)to examine changes in the Northern San Francisco Bay, in particular looking for possiblechanges due to the on-going California drought. For instance, a temporary drought barrier to prevent salt water intrusion was placed during May of 2015 at West False River in the Sacramento-San Joaquin Delta. Using the new Landsat-8 ocean color products, we illustrate how to monitor changes in macro algae and plants (Sago pondweed (native), Curly pondweed (non-native)) in regions directly effected,such as the Franks Track region. Product maps using panchromatic enhancement ( 15 m resolution) andscene based atmospheric correction allow a detailed synoptic look every 16 days during theSpring, Summer, and Fall of 2015. This work is part of a larger NASA funded project aimed atimproving the modeling and predictive capabilities of the biogeochemical state for the San Francisco Bay(Davis, PI: Impacts of Population Growth on the San Francisco Bay and Delta Ecosystem, 2014-2017).

  8. California State Waters Map Series: Drakes Bay and vicinity, California

    Science.gov (United States)

    Watt, Janet T.; Dartnell, Peter; Golden, Nadine E.; Greene, H. Gary; Erdey, Mercedes D.; Cochrane, Guy R.; Johnson, Samuel Y.; Hartwell, Stephen R.; Kvitek, Rikk G.; Manson, Michael W.; Endris, Charles A.; Dieter, Bryan E.; Sliter, Ray W.; Krigsman, Lisa M.; Lowe, Erik N.; Chinn, John L.; Watt, Janet T.; Cochran, Susan A.

    2015-01-01

    In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology.

  9. Evaluation of strength degradation in seismic loading of Holocene bay mud from Marin County, California

    Science.gov (United States)

    Rau, Gretchen Anne

    Cyclic simple shear tests performed on Holocene bay mud at the University of California at Berkeley following the 1989 Loma Prieta earthquake, suggested that the response of silty clay to cyclic loading might be more severe than earlier research had indicated. A program of laboratory testing was therefore carried out to investigate the potential strength degradation of Holocene bay mud subjected to a range of conditions representative of those expected in a major earthquake. The results show that the volumetric cyclic threshold shear strain is between 0.02% and 0.04%. The reduction of shear modulus with increasing strain amplitude is generally consistent with data presented in an earlier study on Holocene bay mud from another location. The damping ratios for the first cycle of loading are consistent with the limits suggested for cohesive soils from earlier studies. The shear stress in the first cycle of loading exhibits approximately a 13--16% increase per order of magnitude increase in strain rate, which is on the higher end of the range of values presented in studies on other cohesive soils. The post-cyclic monotonic strengths are within +/-10% of the monotonic strengths of specimens that had not undergone cyclic loading. There were no clear effects of varying the strain amplitude, frequency of loading, or strain rate, but dissipation of pore pressures between the' end of cyclic loading and the beginning of monotonic shear increases the strength by an average of 8%. One-dimensional site response analysis was performed to estimate the amplitude and number of cycles of shear strain in moderate to large earthquakes, and it showed that up to five cycles or more of shear strain amplitudes exceeding I% could be expected. Therefore, the strength degradation that was observed in the cyclic testing is within the range of interest for geotechnical earthquake engineering. A comparison between the cyclic response of the specimens from Hamilton Air Force Base and specimens

  10. Deployment of the National Transparent Optical Network around the San Francisco Bay Area

    Energy Technology Data Exchange (ETDEWEB)

    McCammon, K.; Haigh, R.; Armstrong, G. [and others

    1996-06-01

    We report on the deployment and initial operation of the National Transparent Optical Network, an experimental WDM network testbed around the San Francisco Bay Area, during the Optical Fiber Conference (OFC`96) held in San Jose, CA. The deployment aspects of the physical plant, optical and SONET layers are examined along with a discussion of broadband applications which utilized the network during the OFC`96 demonstration. The network features dense WDM technology, transparent optical routing technology using acousto- optic tunable filter based switches, and network modules with add/drop, multicast, and wavelength translation capabilities. The physical layer consisted of over 300 km of Sprint and Pacific Bell conventional single mode fiber which was amplified with I I optical amplifiers deployed in pre-amp, post-amp, and line amp configurations. An out-of-band control network provided datacom channels from remote equipment sites to the SONET network manager deployed at the San Jose Convention Center for the conference. Data transport over five wavelengths was achieved in the 1550 nm window using a variety of signal formats including analog and digital signal transmission on different wavelengths on the same fiber. The network operated throughout the week of OFC`96 and is still in operation today.

  11. Estimation of historic flows and sediment loads to San Francisco Bay,1849–2011

    Science.gov (United States)

    Moftakhari, H.R.; Jay, D.A.; Talke, S.A.; Schoellhamer, David H.

    2016-01-01

    River flow and sediment transport in estuaries influence morphological development over decadal and century time scales, but hydrological and sedimentological records are typically too short to adequately characterize long-term trends. In this study, we recover archival records and apply a rating curve approach to develop the first instrumental estimates of daily delta inflow and sediment loads to San Francisco Bay (1849–1929). The total sediment load is constrained using sedimentation/erosion estimated from bathymetric survey data to produce continuous daily sediment transport estimates from 1849 to 1955, the time period prior to sediment load measurements. We estimate that ∼55% (45–75%) of the ∼1500 ± 400 million tons (Mt) of sediment delivered to the estuary between 1849 and 2011 was the result of anthropogenic alteration in the watershed that increased sediment supply. Also, the seasonal timing of sediment flux events has shifted because significant spring-melt floods have decreased, causing estimated springtime transport (April 1st to June 30th) to decrease from ∼25% to ∼15% of the annual total. By contrast, wintertime sediment loads (December 1st to March 31st) have increased from ∼70% to ∼80%. A ∼35% reduction of annual flow since the 19th century along with decreased sediment supply has resulted in a ∼50% reduction in annual sediment delivery. The methods developed in this study can be applied to other systems for which unanalyzed historic data exist.

  12. Dynamic Response of the Suspension Spans of the San Francisco-Oakland Bay Bridge

    Energy Technology Data Exchange (ETDEWEB)

    McCallen, D; Astaneh-Asl, A; Larsen, S; Hutchings, L

    2005-11-03

    The dynamic response of the suspension spans of the San Francisco-Oakland Bay Bridge (SFOBB) have been numerically modeled in a case-study to investigate the effects of long-period, near-field ground motions on flexible suspension bridges. The structural simulation model used in the study was developed as a special purpose computer program tailored to efficiently simulate the nonlinear response of cable supported bridges. The simulation model includes a number of special element technologies and solution algorithms that enable efficient nonlinear analysis of suspension bridges. The ground motions used in the study were site specific synthetic records for a Mw=7.25 earthquake along the Hayward fault at 12-15 km distant, and actual measured near-field records from the Izmit Turkey (1999) and Chi-Chi Taiwan (1999) earthquakes. These records include near- and far-field broad-band motions for three components. The results of the numerical simulations indicate that low frequency waveforms associated with near-field motions can place a significant demand on the structural systems of suspension bridges, and must be accounted for in suspension bridge analysis and design.

  13. Grazer Functional Roles, Induced Defenses, and Indirect Interactions: Implications for Eelgrass Restoration in San Francisco Bay

    Directory of Open Access Journals (Sweden)

    Jeffrey T. Lewis

    2014-11-01

    Full Text Available Understanding the individual and interactive roles of consumer species is more than academic when the host plant is a subject of intense conservation interest. In a mesocosm experiment, we compared effects of common invertebrate grazers in San Francisco Bay seagrass (Zostera marina, eelgrass beds, finding that some species (a native opisthobranch, Phyllaplysia taylori; a native isopod, Idotea resecata; and an introduced gastropod, Ilyanassa obsoleta enhanced eelgrass growth through removal of epiphytic algae, as is often predicted for small invertebrate grazers on seagrasses, while one (an introduced caprellid amphipod, Caprella cf. drepanochir had neutral effects. In contrast, the putatively-introduced gammaridean amphipod, Ampithoe valida, had strong negative effects on eelgrass (in addition to epiphytes through consumption, as we had previously observed in the field during restoration programs. We tested whether other common grazer species could influence the effects of the eelgrass-grazing Ampithoe, and found that Idotea induced production of phenolic compounds and limited eelgrass damage by Ampithoe, without affecting Ampithoe abundance. These results have implications for restoration strategies, and contribute to a growing awareness of the importance of trait-mediated indirect grazer interactions through grazer-induced changes in plant traits, providing the first example in a seagrass system.

  14. A Viscoelastic earthquake simulator with application to the San Francisco Bay region

    Science.gov (United States)

    Pollitz, F.F.

    2009-01-01

    Earthquake simulation on synthetic fault networks carries great potential for characterizing the statistical patterns of earthquake occurrence. I present an earthquake simulator based on elastic dislocation theory. It accounts for the effects of interseismic tectonic loading, static stress steps at the time of earthquakes, and postearthquake stress readjustment through viscoelastic relaxation of the lower crust and mantle. Earthquake rupture initiation and termination are determined with a Coulomb failure stress criterion and the static cascade model. The simulator is applied to interacting multifault systems: one, a synthetic two-fault network, and the other, a fault network representative of the San Francisco Bay region. The faults are discretized both along strike and along dip and can accommodate both strike slip and dip slip. Stress and seismicity functions are evaluated over 30,000 yr trial time periods, resulting in a detailed statistical characterization of the fault systems. Seismicity functions such as the coefficient of variation and a- and b-values exhibit systematic patterns with respect to simple model parameters. This suggests that reliable estimation of the controlling parameters of an earthquake simulator is a prerequisite to the interpretation of its output in terms of seismic hazard.

  15. Downscaling future climate projections to the watershed scale: a north San Francisco Bay estuary case study

    Science.gov (United States)

    Micheli, Elisabeth; Flint, Lorraine; Flint, Alan; Weiss, Stuart; Kennedy, Morgan

    2012-01-01

    We modeled the hydrology of basins draining into the northern portion of the San Francisco Bay Estuary (North San Pablo Bay) using a regional water balance model (Basin Characterization Model; BCM) to estimate potential effects of climate change at the watershed scale. The BCM calculates water balance components, including runoff, recharge, evapotranspiration, soil moisture, and stream flow, based on climate, topography, soils and underlying geology, and the solar-driven energy balance. We downscaled historical and projected precipitation and air temperature values derived from weather stations and global General Circulation Models (GCMs) to a spatial scale of 270 m. We then used the BCM to estimate hydrologic response to climate change for four scenarios spanning this century (2000–2100). Historical climate patterns show that Marin’s coastal regions are typically on the order of 2 °C cooler and receive five percent more precipitation compared to the inland valleys of Sonoma and Napa because of marine influences and local topography. By the last 30 years of this century, North Bay scenarios project average minimum temperatures to increase by 1.0 °C to 3.1 °C and average maximum temperatures to increase by 2.1 °C to 3.4 °C (in comparison to conditions experienced over the last 30 years, 1981–2010). Precipitation projections for the 21st century vary between GCMs (ranging from 2 to 15% wetter than the 20th-century average). Temperature forcing increases the variability of modeled runoff, recharge, and stream discharge, and shifts hydrologic cycle timing. For both high- and low-rainfall scenarios, by the close of this century warming is projected to amplify late-season climatic water deficit (a measure of drought stress on soils) by 8% to 21%. Hydrologic variability within a single river basin demonstrated at the scale of subwatersheds may prove an important consideration for water managers in the face of climate change. Our results suggest that in arid

  16. Forecasting selenium discharges to the San Francisco Bay-Delta Estuary: ecological effects of a proposed San Luis drain extension

    Science.gov (United States)

    Luoma, Samuel N.; Presser, Theresa S.

    2000-01-01

    During the next few years, federal and state agencies may be required to evaluate proposals and discharge permits that could significantly change selenium (Se) inputs to the San Francisco Bay-Delta Estuary (Bay-Delta), particularly in the North Bay (i.e., Suisun Bay and San Pablo Bay). These decisions may include discharge requirements for an extension of the San Luis Drain (SLD) to the estuary to convey subsurface agricultural drainage from the western San Joaquin Valley (SJV), a renewal of an agreement to allow the existing portion of the SLD to convey subsurface agricultural drainage to a tributary of the San Joaquin River (SJR) (coincident with changes in flow patterns of the lower SJR), and refinements to promulgated Se criteria for the protection of aquatic life for the estuary. Understanding the biotransfer of Se is essential to evaluating the fate and impact of proposed changes in Se discharges to the Bay-Delta. However, past monitoring programs have not addressed the specific protocols necessary for an element that bioaccumulates. Confusion about Se threats in the past have stemmed from failure to consider the full complexity of the processes that result in Se toxicity. Past studies show that predators are more at risk from Se contamination than their prey, making it difficult to use traditional methods to predict risk from environmental concentrations alone. In this report, we employ a novel procedure to model the fate of Se under different, potentially realistic load scenarios from the SJV. For each potential load, we progressively forecast the resulting environmental concentrations, speciation, transformation to particulate form, bioaccumulation by invertebrates, trophic transfer to predators, and effects in those predators. Enough is known to establish a first order understanding of effects should Se be discharged directly into the North Bay via a conveyance such as the SLD. Our approach uses 1) existing knowledge concerning the biogeochemical

  17. 78 FR 2952 - Foreign-Trade Zone 3-San Francisco, California; Application for Expansion and Expansion of...

    Science.gov (United States)

    2013-01-15

    ... on January 9, 2013. FTZ 3 was approved by the Board on March 10, 1948 (Board Order 12, 13 FR 1459, 3/19/48) and the zone was reorganized under the ASF on October 7, 2010 (Board Order 1718, 75 FR 64708... Foreign-Trade Zones Board Foreign-Trade Zone 3--San Francisco, California; Application for Expansion...

  18. A physical model for strain accumulation in the San Francisco Bay Region

    Science.gov (United States)

    Pollitz, F.F.; Nyst, M.

    2005-01-01

    Strain accumulation in tectonically active regions is generally a superposition of the effects of background tectonic loading, steady-state dislocation processes, such as creep, and transient deformation. In the San Francisco Bay region (SFBR), the most uncertain of these processes is transient deformation, which arises primarily in association with large earthquakes. As such, it depends upon the history of faulting and the rheology of the crust and mantle, which together determine the pattern of longer term (decade-scale) post-seismic response to earthquakes. We utilize a set of 102 GPS velocity vectors in the SFBR in order to characterize the strain rate field and construct a physical model of its present deformation. We first perform an inversion for the continuous velocity gradient field from the discrete GPS velocity field, from which both tensor strain rate and rotation rate may be extracted. The present strain rate pattern is well described as a nearly uniform shear strain rate oriented approximately N34??W (140 nanostrain yr-1) plus a N56??E uniaxial compression rate averaging 20 nanostrain yr-1 across the shear zone. We fit the velocity and strain rate fields to a model of time-dependent deformation within a 135-kin-wide, arcuate shear zone bounded by strong Pacific Plate and Sierra Nevada block lithosphere to the SW and NE, respectively. Driving forces are purely lateral, consisting of shear zone deformation imposed by the relative motions between the thick Pacific Plate and Sierra Nevada block lithospheres. Assuming a depth-dependent viscoelastic structure within the shear zone, we account for the effects of steady creep on faults and viscoelastic relaxation following the 1906 San Francisco and 1989 Loma Prieta earthquakes, subject to constant velocity boundary conditions on the edges of the shear zone. Fault creep is realized by evaluating dislocations on the creeping portions of faults in the fluid limit of the viscoelastic model. A priori plate

  19. A Proposed Physical Model of Strain Accumulation in the San Francisco Bay Region

    Science.gov (United States)

    Pollitz, F. F.; Nyst, M. C.

    2002-12-01

    Strain accumulation in tectonically active regions is dependent on several factors, including background tectonic loading, steady-state dislocation processes such as creep, and transient deformation. In the San Francisco Bay (SFB) region, the most uncertain of these processes is transient deformation, which arises primarily in association with large historic earthquakes. As such it depends upon the history of faulting and the rheology of the crust and mantle, which together determine the pattern of longer-term (decade-scale) postseismic response to earthquakes. We utilize a set of 99 GPS velocity vectors in the SFB region in order to characterize the strain field and construct a physical model of its present deformation. We first perform an inversion for the continuous velocity gradient field from the discrete GPS velocity field, from which both tensor strain and rotation may be extracted. We then fit this strain field to a model of time-dependent deformation within a 135 km-wide, arcuate shear zone bounded by strong Pacific plate and Sierra Nevada block lithosphere to the SW and NE, respectively. Driving forces are purely lateral, consisting of shear zone deformation imposed by the relative motions between the thick Pacific plate and Sierra Nevada block lithospheres. Assuming depth-dependent viscoelastic structure within the shear zone, we account for the effects of steady creep on faults and viscoelastic relaxation following the 1906 San Francisco and 1989 Loma Prieta earthquakes, subject to constant velocity boundary conditions on the edges of the shear zone: 38 mm/yr fault-parallel motion and variable fault-perpendicular motion. Fault creep is realized by evaluating dislocations on the creeping portions of faults in the fluid limit of the viscoelastic model. The present strain pattern is well-described as a nearly uniform shear strain oriented approximately N35° W (140 nanostrain/yr) plus a more heterogeneous N55° E uniaxial compression averaging 20

  20. A physical model for strain accumulation in the San Francisco Bay Region

    Science.gov (United States)

    Pollitz, Fred F.; Nyst, Marleen

    2005-01-01

    Strain accumulation in tectonically active regions is generally a superposition of the effects of background tectonic loading, steady-state dislocation processes, such as creep, and transient deformation. In the San Francisco Bay region (SFBR), the most uncertain of these processes is transient deformation, which arises primarily in association with large earthquakes. As such, it depends upon the history of faulting and the rheology of the crust and mantle, which together determine the pattern of longer term (decade-scale) post-seismic response to earthquakes. We utilize a set of 102 GPS velocity vectors in the SFBR in order to characterize the strain rate field and construct a physical model of its present deformation. We first perform an inversion for the continuous velocity gradient field from the discrete GPS velocity field, from which both tensor strain rate and rotation rate may be extracted. The present strain rate pattern is well described as a nearly uniform shear strain rate oriented approximately N34°W (140 nanostrain yr-1) plus a N56°E uniaxial compression rate averaging 20 nanostrain yr-1 across the shear zone. We fit the velocity and strain rate fields to a model of time-dependent deformation within a 135-km-wide, arcuate shear zone bounded by strong Pacific Plate and Sierra Nevada block lithosphere to the SW and NE, respectively. Driving forces are purely lateral, consisting of shear zone deformation imposed by the relative motions between the thick Pacific Plate and Sierra Nevada block lithospheres. Assuming a depth-dependent viscoelastic structure within the shear zone, we account for the effects of steady creep on faults and viscoelastic relaxation following the 1906 San Francisco and 1989 Loma Prieta earthquakes, subject to constant velocity boundary conditions on the edges of the shear zone. Fault creep is realized by evaluating dislocations on the creeping portions of faults in the fluid limit of the viscoelastic model. A priori plate

  1. Slicing up the San Francisco Bay Area: Block kinematics and fault slip rates from GPS-derived surface velocities

    Science.gov (United States)

    D'Alessio, M. A.; Johanson, I. A.; Bürgmann, R.; Schmidt, D. A.; Murray, M. H.

    2005-06-01

    Observations of surface deformation allow us to determine the kinematics of faults in the San Francisco Bay Area. We present the Bay Area velocity unification (B?V?, "bay view"), a compilation of over 200 horizontal surface velocities computed from campaign-style and continuous Global Positioning System (GPS) observations from 1993 to 2003. We interpret this interseismic velocity field using a three-dimensional block model to determine the relative contributions of block motion, elastic strain accumulation, and shallow aseismic creep. The total relative motion between the Pacific plate and the rigid Sierra Nevada/Great Valley (SNGV) microplate is 37.9 ± 0.6 mm yr-1 directed toward N30.4°W ± 0.8° at San Francisco (±2σ). Fault slip rates from our preferred model are typically within the error bounds of geologic estimates but provide a better fit to geodetic data (notable right-lateral slip rates in mm yr-1: San Gregorio fault, 2.4 ± 1.0; West Napa fault, 4.0 ± 3.0; zone of faulting along the eastern margin of the Coast Range, 5.4 ± 1.0; and Mount Diablo thrust, 3.9 ± 1.0 of reverse slip and 4.0 ± 0.2 of right-lateral strike slip). Slip on the northern Calaveras is partitioned between both the West Napa and Concord/Green Valley fault systems. The total convergence across the Bay Area is negligible. Poles of rotation for Bay Area blocks progress systematically from the North America-Pacific to North America-SNGV poles. The resulting present-day relative motion cannot explain the strike of most Bay Area faults, but fault strike does loosely correlate with inferred plate motions at the time each fault initiated.

  2. Map showing locations of damaging landslides in San Francisco City and County, California, resulting from 1997-98 El Nino rainstorms

    Science.gov (United States)

    Hillhouse, John W.; Godt, Jonathan W.

    1999-01-01

    Heavy rainfall associated with a strong El Nino caused over $150 million in landslide damage in the 10-county San Francisco Bay region during the winter and spring of 1998. A team of USGS scientists collected information on landslide locations and damage costs. About $4 million in damages were assessed in San Francisco City and County.

  3. Vertical tectonic deformation associated with the San Andreas fault zone offshore of San Francisco, California

    Science.gov (United States)

    Ryan, H. F.; Parsons, T.; Sliter, R. W.

    2008-10-01

    A new fault map of the shelf offshore of San Francisco, California shows that faulting occurs as a distributed shear zone that involves many fault strands with the principal displacement taken up by the San Andreas fault and the eastern strand of the San Gregorio fault zone. Structures associated with the offshore faulting show compressive deformation near where the San Andreas fault goes offshore, but deformation becomes extensional several km to the north off of the Golden Gate. Our new fault map serves as the basis for a 3-D finite element model that shows that the block between the San Andreas and San Gregorio fault zone is subsiding at a long-term rate of about 0.2-0.3 mm/yr, with the maximum subsidence occurring northwest of the Golden Gate in the area of a mapped transtensional basin. Although the long-term rates of vertical displacement primarily show subsidence, the model of coseismic deformation associated with the 1906 San Francisco earthquake indicates that uplift on the order of 10-15 cm occurred in the block northeast of the San Andreas fault. Since 1906, 5-6 cm of regional subsidence has occurred in that block. One implication of our model is that the transfer of slip from the San Andreas fault to a fault 5 km to the east, the Golden Gate fault, is not required for the area offshore of San Francisco to be in extension. This has implications for both the deposition of thick Pliocene-Pleistocene sediments (the Merced Formation) observed east of the San Andreas fault, and the age of the Peninsula segment of the San Andreas fault.

  4. Crustal structure from San Francisco, California, to Eureka, Nevada, from seismic-refraction measurements

    Science.gov (United States)

    Eaton, Jerry P.

    1963-01-01

    Seismic-refraction measurements from chemical explosions near San Francisco, California, and Fallon and Eureka, Nevada, were made along a line extending nearly 700 km inland from San Francisco across the Coast Ranges, Great Valley, Sierra Nevada, and Basin and Range Province. The velocity of Pg in the Basin and Range Province was found to be 6.0 km/sec. Between Fallon and Eureka the velocity of Pn is 7.8 km/sec, and just east of the Sierra Nevada it is about 7.9 km/sec. Two prominent phases closely following the first arrival between 50 and 250 km from the source in the Basin and Range Province were interpreted as reflections from an intermediate layer and from the Mohorovicic discontinuity. The velocity of P in the possible intermediate layer, deduced from the reflected phases be cause the refracted wave expected from this layer is nowhere a first arrival, seems to be 6.6 km/sec at the top of the layer and probably increases with depth.

  5. Preliminary Results from Real-Time GPS Monitoring in the San Francisco Bay Area

    Science.gov (United States)

    Langbein, J. O.; Guillemot, C.

    2013-12-01

    A web-based monitoring system has been implemented to display displacement estimates in real-time for various combinations of USGS, Plate Boundary Observatory (PBO) and Bay Area Regional Deformation (BARD) network stations in the San Francisco Bay area. Tools and utilities developed in-house are used to visually analyze the quality of estimated positions and gain a better understanding of the challenges involved in integrating displacement data into earthquake early warning (EEW) algorithms. Comparisons of results between differential and precise position estimates obtained from a variety of software packages have led to a closer examination of the epoch-per-epoch latencies, or delays with which those estimates are generated. For example, although position estimates from precise point positioning, with ambiguity resolution, (PPP-AR) computed in real-time are reasonably stable over short-time scales, latencies of 50 seconds or more currently preclude their useful incorporation into EEW algorithms. On the other hand, the latencies for differential position range between less than a second to 10 seconds. The large latencies for PPP-AR are partly due to the fact that displacement estimates obtained from GPS cannot yet be generated at the source but must rely on centralized processing that incorporates instantaneous clock corrections which, in turn must be obtained from external agencies. The latencies, however, are not as critical for the study of post-seismic deformation that occurs minutes to hours following an earthquake. Computation of the power spectra of time series provides a quantitative means to compare the precision of estimated positions that are obtained from various software that process the data in real-time. To first order, the current set of processing algorithms, including those using differential position and PPP-AR, provides nearly equal performance in terms of temporal correlations which is represented by their power spectra. At the shortest periods

  6. Slip rates on San Francisco Bay area faults from anelastic deformation of the continental lithosphere

    Science.gov (United States)

    Geist, Eric L.; Andrews, D. J.

    2000-11-01

    Long-term slip rates on major faults in the San Francisco Bay area are predicted by modeling the anelastic deformation of the continental lithosphere in response to regional relative plate motion. The model developed by Bird and Kong [1994] is used to simulate lithospheric deformation according to a Coulomb frictional rheology of the upper crust and a dislocation creep rheology at depth. The focus of this study is the long-term motion of faults in a region extending from the creeping section of the San Andreas fault to the south up to the latitude of Cape Mendocino to the north. Boundary conditions are specified by the relative motion between the Pacific plate and the Sierra Nevada-Great Valley microplate [Argus and Gordon, 2000]. Rheologic-frictional parameters are specified as independent variables, and prediction errors are calculated with respect to geologic estimates of slip rates and maximum compressive stress directions. The model that best explains the region-wide observations is one in which the coefficient of friction on all of the major faults is less than 0.15, with the coefficient of friction for the San Andreas fault being approximately 0.09, consistent with previous inferences of San Andreas fault friction. Prediction error increases with lower fault friction on the San Andreas, indicating a lower bound of μSAF > 0.08. Discrepancies with respect to previous slip rate estimates include a higher than expected slip rate along the peninsula segment of the San Andreas fault and a slightly lower than expected slip rate along the San Gregorio fault.

  7. Geodetic estimates of fault slip rates in the San Francisco Bay area

    Science.gov (United States)

    Savage, J. C.; Svarc, J. L.; Prescott, W. H.

    1999-03-01

    Bourne et al. [1998] have suggested that the interseismic velocity profile at the surface across a transform plate boundary is a replica of the secular velocity profile at depth in the plastosphere. On the other hand, in the viscoelastic coupling model the shape of the interseismic surface velocity profile is a consequence of plastosphere relaxation following the previous rupture of the faults that make up the plate boundary and is not directly related to the secular flow in the plastosphere. The two models appear to be incompatible. If the plate boundary is composed of several subparallel faults and the interseismic surface velocity profile across the boundary known, each model predicts the secular slip rates on the faults which make up the boundary. As suggested by Bourne et al., the models can then be tested by comparing the predicted secular slip rates to those estimated from long-term offsets inferred from geology. Here we apply that test to the secular slip rates predicted for the principal faults (San Andreas, San Gregorio, Hayward, Calaveras, Rodgers Creek, Green Valley and Greenville faults) in the San Andreas fault system in the San Francisco Bay area. The estimates from the two models generally agree with one another and to a lesser extent with the geologic estimate. Because the viscoelastic coupling model has been equally successful in estimating secular slip rates on the various fault strands at a diffuse plate boundary, the success of the model of Bourne et at. [1998] in doing the same thing should not be taken as proof that the interseismic velocity profile across the plate boundary at the surface is a replica of the velocity profile at depth in the plastosphere.

  8. Linkage of bioaccumulation and biological effects to changes in pollutant loads in south San Francisco Bay

    Science.gov (United States)

    Hornberger, M.I.; Luoma, S.N.; Cain, D.J.; Parchaso, F.; Brown, C.L.; Bouse, R.M.; Wellise, C.; Thompson, J.K.

    2000-01-01

    The developed world has invested billions of dollars in waste treatment since the 1970s; however, changes in ecological or biological responses are rarely associated with reductions in metal pollutants. Here we present a novel, 23-yr time series of environmental change from a San Francisco Bay mudflat located 1 km from the discharge of a suburban domestic sewage treatment plant. Samples of surface sediment, the bioindicator Macoma balthica, and metals loading data were used to establish links between discharge, bioaccumulation, and effects. Mean annual Ag concentrations in M. balthica were 106 ??g/g in 1978 and 3.67 ??g/g in 1998. Concentrations of Cu declined from 287 ??g/g in 1980 to a minimum of 24 ??g/g in 1991. Declining Cu bioaccumulation was strongly correlated with decreasing Cu loads from the plant between 1977 and 1998. Relationships with bioaccumulation and total annual precipitation suggested that inputs from nonpoint sources were most important in controlling Zn bioavailability during the same period. Ecoepidemiological criteria were used to associate failed gamete production in M. balthica to a metals-enriched environment. Reproduction persistently failed between the mid-1970s and mid-1980s; it recovered after metal contamination declined. Other potential environmental causes such as food availability, sediment chemistry, or seasonal salinity fluctuations were not related to the timing of the change in reproductive capability. The results establish an associative link, suggesting that it is important to further investigate the chemical interference of Cu and/or Ag with invertebrate reproduction at relatively moderate levels of environmental contamination.

  9. Probabilistic seismic hazard in the San Francisco Bay area based on seismicity simulation

    Science.gov (United States)

    Pollitz, F. F.

    2008-12-01

    Understanding how fault systems evolve in time under a relevant set of governing physical laws is a needed critical step towards reliable earthquake forecasting. We can address issues relevant to probabilistic seismic hazard analysis (e.g. recurrence time, coefficient of variation, probability of multi-segment rupture) with numerical simulations of seismicity. A seismicity simulator essentially provides a means of tracking the increasing tectonic stress as it loads the faults and determines how stress is redistributed among the network faults as the result of an earthquake. I implement a seismicity simulator that includes the effects of: (1) tectonic loading of a plate boundary zone; (2) static stress transfer; (3) viscoelasticity of the ductile lower crust and mantle; (4) length- and depth-dependent fault slip. I apply it to a network of multiple interacting faults in the San Francisco Bay area. Earthquake initiation, propagation, and termination are governed by a cascade model using a Coulomb failure function. 30000 years of simulated seismicity yield probability density functions of inter-event times on all major faults at practically a continuum of magnitude thresholds. At a threshold of M6.5, reasonable combinations of controlling parameters yield mean inter-event times of ~ 140 years for the southern Hayward and Rodgers Creek faults and ~ 250 years for the northern Hayward and northern Calaveras faults. To help interpret simulation results I explore systematic covariations among mean characteristic magnitude, coefficient of variation (typical values are 0.4 to 0.6), degree of dynamic overshoot, and mantle viscosity.

  10. Stress-based aftershock forecasts made within 24h post mainshock: Expected north San Francisco Bay area seismicity changes after the 2014M=6.0 West Napa earthquake

    Science.gov (United States)

    Parsons, Thomas E.; Segou, Margaret; Sevilgen, Volkan; Milner, Kevin; Field, Ned; Toda, Shinji; Stein, Ross S.

    2014-01-01

    We calculate stress changes resulting from the M= 6.0 West Napa earthquake on north San Francisco Bay area faults. The earthquake ruptured within a series of long faults that pose significant hazard to the Bay area, and we are thus concerned with potential increases in the probability of a large earthquake through stress transfer. We conduct this exercise as a prospective test because the skill of stress-based aftershock forecasting methodology is inconclusive. We apply three methods: (1) generalized mapping of regional Coulomb stress change, (2) stress changes resolved on Uniform California Earthquake Rupture Forecast faults, and (3) a mapped rate/state aftershock forecast. All calculations were completed within 24 h after the main shock and were made without benefit of known aftershocks, which will be used to evaluative the prospective forecast. All methods suggest that we should expect heightened seismicity on parts of the southern Rodgers Creek, northern Hayward, and Green Valley faults.

  11. Stress-based aftershock forecasts made within 24 h postmain shock: Expected north San Francisco Bay area seismicity changes after the 2014 M = 6.0 West Napa earthquake

    Science.gov (United States)

    Parsons, Tom; Segou, Margaret; Sevilgen, Volkan; Milner, Kevin; Field, Edward; Toda, Shinji; Stein, Ross S.

    2014-12-01

    We calculate stress changes resulting from the M = 6.0 West Napa earthquake on north San Francisco Bay area faults. The earthquake ruptured within a series of long faults that pose significant hazard to the Bay area, and we are thus concerned with potential increases in the probability of a large earthquake through stress transfer. We conduct this exercise as a prospective test because the skill of stress-based aftershock forecasting methodology is inconclusive. We apply three methods: (1) generalized mapping of regional Coulomb stress change, (2) stress changes resolved on Uniform California Earthquake Rupture Forecast faults, and (3) a mapped rate/state aftershock forecast. All calculations were completed within 24 h after the main shock and were made without benefit of known aftershocks, which will be used to evaluative the prospective forecast. All methods suggest that we should expect heightened seismicity on parts of the southern Rodgers Creek, northern Hayward, and Green Valley faults.

  12. Drought and ice plant invasion in Bodega Bay, California

    Science.gov (United States)

    Weill, A.

    2014-12-01

    Ice plant (Carpobrotus edulis) is a succulent native to South Africa that is widespread in coastal California. Ice plant invasion is facilitated by the plant's ability to compete for water. More frequent drought due to climate change could enhance the invasive potential of ice plant due to its succulent properties and potential to access and compete for water under drought conditions. However, ice plant spread may be slowed due to water stress under drought despite a potential competitive advantage. We test the alternative hypotheses that invasive potential increases or decreases during times of drought by analyzing ice plant spread during past droughts at Bodega Bay, California using analysis of aerial photographs taken over the last two decades. The results of this analysis may reveal how ice plant may behave in future drought years and provide useful information for invasive species management.

  13. California bay laurel susceptibility to Phythophthora ramorum depends upon season, leaf age, and fungal load

    Science.gov (United States)

    Steve Johnston; Nathan Rank; Michael Cohen; Ross Meentemeyer

    2010-01-01

    Phytophthora ramorum can produce spores on dozens of native California plant species, but the most important vector for infection of oak (Quercus) is California bay laurel (Umbellularia californica). Presence of bay laurel is associated with increased infection of oaks and it is the most common tree...

  14. Novel Technique for Assessing Ammonium Utilization by Phytoplankton in the San Francisco Bay-Delta Estuary

    Science.gov (United States)

    Schmidt, C. M.; Kendall, C.; Young, M. B.; Kraus, T. E. C.; Silva, S. R.; Richter, M. T.

    2015-12-01

    High concentrations of NH4+ in the San Francisco Bay-Delta Estuary (SFE) have been shown to inhibit the growth of phytoplankton, which are an important food source to zooplankton at the base of the pelagic food web. Here we present results from a study which used a stable isotope mixing model to quantify the proportion of nitrogen assimilated as NH4+ by phytoplankton in situ in a portion of the Sacramento River where NH4+ concentration is elevated downstream of the Sacramento Regional Wastewater Treatment Plant (SRWTP). To determine the δ15N value of phytoplankton, a novel method was developed to isolate phytoplankton from bulk particulate organic matter using flow cytometry prior to isotopic analysis. Modifications were made to an elemental analyzer to allow measurement of the δ15N values of samples containing as little as 0.5 µg N with an analytical precision of 0.2‰ (determined from replicate analysis of standards). During fall and spring field campaigns, two parcels of Sacramento River water (one with wastewater effluent and one without) were tracked and sampled in a Lagrangian sampling scheme over ~80 hours of travel downstream of the SRWTP. Water samples were analyzed for nutrient and chlorophyll concentrations as well δ15N-NO3 and δ15N-NH4+. In addition, approximately ten million phytoplankton cells were sorted from each sample for analysis of δ15N-phytoplankton. In parcels of Sacramento River water without wastewater effluent, NH4+ concentrations remained low and trends in δ15N-phytoplankton followed trends in δ15N-NO3-. In contrast, in the parcels containing SRWTP effluent phytoplankton uptake of N as NH4+ gradually increased from 15% immediately downstream of the SRWTP to as high as 90% after 80 hours of downstream transit. Previous mesocosm incubation experiments have demonstrated depressed growth rates and a rapid switch from NO3- to NH4+ uptake downstream of the SRWTP, suggesting that the apparent gradual increase in the proportion of N

  15. [Don Edwards San Francisco Bay National Wildlife Refuge: Final Comprehensive Conservation Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Comprehensive Conservation Plan (CCP) executive summary was written to guide management on Don Edwards San Francisco National Wildlife Refuge for the next 15...

  16. Food insecurity, chronic illness, and gentrification in the San Francisco Bay Area: An example of structural violence in United States public policy.

    Science.gov (United States)

    Whittle, Henry J; Palar, Kartika; Hufstedler, Lee Lemus; Seligman, Hilary K; Frongillo, Edward A; Weiser, Sheri D

    2015-10-01

    Food insecurity continues to be a major challenge in the United States, affecting 49 million individuals. Quantitative studies show that food insecurity has serious negative health impacts among individuals suffering from chronic illnesses, including people living with HIV/AIDS (PLHIV). Formulating effective interventions and policies to combat these health effects requires an in-depth understanding of the lived experience and structural drivers of food insecurity. Few studies, however, have elucidated these phenomena among people living with chronic illnesses in resource-rich settings, including in the United States. Here we sought to explore the experiences and structural determinants of food insecurity among a group of low-income PLHIV in the San Francisco Bay Area. Thirty-four semi-structured in-depth interviews were conducted with low-income PLHIV receiving food assistance from a local non-profit in San Francisco and Alameda County, California, between April and June 2014. Interview transcripts were coded and analysed according to content analysis methods following an inductive-deductive approach. The lived experience of food insecurity among participants included periods of insufficient quantity of food and resultant hunger, as well as long-term struggles with quality of food that led to concerns about the poor health effects of a cheap diet. Participants also reported procuring food using personally and socially unacceptable strategies, including long-term dependence on friends, family, and charity; stealing food; exchanging sex for food; and selling controlled substances. Food insecurity often arose from the need to pay high rents exacerbated by gentrification while receiving limited disability income--​a situation resulting in large part from the convergence of long-standing urban policies amenable to gentrification and an outdated disability policy that constrains financial viability. The experiences of food insecurity described by participants in this

  17. Interseismic interactions in geometrically complex fault systems: Implications for San Francisco Bay Area fault creep and tectonics

    Science.gov (United States)

    Evans, E. L.; Meade, B. J.; Loveless, J. P.

    2010-12-01

    Fault systems at active plate boundaries accommodate the differential motion of tectonic plates through slip on anastomosing faults within the seismogenic upper crust. The partitioning of slip across fault systems can be inferred from models of space-based geodetic measurements to estimate both fault slip rates and interseismic fault creep. Covariance between slip rate estimates on sub-parallel faults may be significant but can be reduced with the addition of the fundamental constraint that total slip across a fault system must sum to the differential plate motion rate. The importance of ensuring such kinematic consistency becomes increasingly important in strike-slip fault systems such as in the San Francisco Bay Area, where slip is localized across 4-8 sub-parallel faults with San Francisco Bay Area constrained by both GPS and InSAR observations and find that this effect may lead to a substantial revision of interseismic creep estimates on the Hayward fault by as much as 6 mm/yr at depth.

  18. Health-hazard evaluation report HETA 86-236-1725, San Francisco Opera Costume Shop, San Francisco, California

    Energy Technology Data Exchange (ETDEWEB)

    Belanger, P.L.; Okawa, M.T.

    1986-09-01

    An employee representative of the San Francisco Opera Costume Shop requested an investigation of possible exposure to chemical substances by crafts persons and textile artists. No overexposure to chemicals was found during cloth stripping and dying operations, boot deglazing, hat lacquering, fabric painting or casting operations. During boot spray painting, two personal air samples contained methylene chloride at 11.9 and 25 parts per million; both above the NIOSH recommended criteria for methylene-chloride exposure.

  19. Anthropogenic currents and shoreline water quality in Avalon Bay, California.

    Science.gov (United States)

    Ho, Lin C; Litton, Rachel M; Grant, Stanley B

    2011-03-15

    Shoreline concentrations of fecal indicator bacteria (FIB) and fecal indicator viruses (FIV) in Avalon Bay (Catalina Island, California) display a marked diurnal pattern (higher at night and lower during the day) previously attributed to the tidal flux of sewage-contaminated groundwater and the tidal washing of contaminated sediments, coupled with light and dark die-off of FIB and FIV (Boehm, et al., Environ. Sci. Technol. 2009, 43, 8046-8052). In this paper we document the existence of strong (peak velocities between 20 to 40 cm/s) transient currents in the nearshore waters of Avalon Bay that occur between 07:00 and 20:00 each day. These currents, which have a significant onshore component, are generated by anthropogenic activities in the Bay, including prop wash from local boat traffic and the docking practices of large passenger ferries. A budget analysis carried out on simultaneous measurements of FIB at two cross-shore locations indicates that anthropogenic currents contribute to the diurnal cycling of FIB concentrations along the shoreline, by transporting relatively unpolluted water from offshore toward the beach. The data and analysis presented in this paper support the idea that anthropogenic currents represent a significant, and previously overlooked, source of variability in shoreline water quality.

  20. Outdoor Air Pollution (PM2.5) and Ill-Health Attributable to Residential Wood Combustion in the San Francisco Bay Area

    Science.gov (United States)

    Chafe, Z.; Fairley, D.; Smith, K. R.

    2015-12-01

    Residential wood combustion is recognized as a major source of fine particulate (PM2.5) air pollution in the San Francisco Bay Area, especially during the winter heating season. Both indoor and outdoor exposure to air pollution from residential wood combustion negatively impact human health, causing premature deaths and ill-health. Previous research has described the regional impact of wood smoke on air quality. Here, we estimate by county the proportion of ambient (outdoor) PM2.5 air pollution attributable to residential wood combustion in the San Francisco Bay Area. We also explore the implications of residential wood burning emissions for human health in the San Francisco Bay Area, reporting the burden of disease associated with this emission source by county. We also describe differences between counties in wood burning behavior, air pollution levels, and human health effects. The results of this research have relevance for air quality regulation and source abatement prioritization in the San Francisco Bay Area and beyond.

  1. Modeling Magnetic Fields from a DC Power Cable Buried Beneath San Francisco Bay Based on Empirical Measurements.

    Directory of Open Access Journals (Sweden)

    Robert Kavet

    Full Text Available The Trans Bay Cable (TBC is a ±200-kilovolt (kV, 400 MW 85-km long High Voltage Direct Current (DC buried transmission line linking Pittsburg, CA with San Francisco, CA (SF beneath the San Francisco Estuary. The TBC runs parallel to the migratory route of various marine species, including green sturgeon, Chinook salmon, and steelhead trout. In July and August 2014, an extensive series of magnetic field measurements were taken using a pair of submerged Geometrics magnetometers towed behind a survey vessel in four locations in the San Francisco estuary along profiles that cross the cable's path; these included the San Francisco-Oakland Bay Bridge (BB, the Richmond-San Rafael Bridge (RSR, the Benicia-Martinez Bridge (Ben and an area in San Pablo Bay (SP in which a bridge is not present. In this paper, we apply basic formulas that ideally describe the magnetic field from a DC cable summed vectorially with the background geomagnetic field (in the absence of other sources that would perturb the ambient field to derive characteristics of the cable that are otherwise not immediately observable. Magnetic field profiles from measurements taken along 170 survey lines were inspected visually for evidence of a distinct pattern representing the presence of the cable. Many profiles were dominated by field distortions unrelated to the cable caused by bridge structures or other submerged objects, and the cable's contribution to the field was not detectable. BB, with 40 of the survey lines, did not yield usable data for these reasons. The unrelated anomalies could be up to 100 times greater than those from the cable. In total, discernible magnetic field profiles measured from 76 survey lines were regressed against the equations, representing eight days of measurement. The modeled field anomalies due to the cable (the difference between the maximum and minimum field along the survey line at the cable crossing were virtually identical to the measured values. The

  2. Modeling Magnetic Fields from a DC Power Cable Buried Beneath San Francisco Bay Based on Empirical Measurements.

    Science.gov (United States)

    Kavet, Robert; Wyman, Megan T; Klimley, A Peter

    2016-01-01

    The Trans Bay Cable (TBC) is a ±200-kilovolt (kV), 400 MW 85-km long High Voltage Direct Current (DC) buried transmission line linking Pittsburg, CA with San Francisco, CA (SF) beneath the San Francisco Estuary. The TBC runs parallel to the migratory route of various marine species, including green sturgeon, Chinook salmon, and steelhead trout. In July and August 2014, an extensive series of magnetic field measurements were taken using a pair of submerged Geometrics magnetometers towed behind a survey vessel in four locations in the San Francisco estuary along profiles that cross the cable's path; these included the San Francisco-Oakland Bay Bridge (BB), the Richmond-San Rafael Bridge (RSR), the Benicia-Martinez Bridge (Ben) and an area in San Pablo Bay (SP) in which a bridge is not present. In this paper, we apply basic formulas that ideally describe the magnetic field from a DC cable summed vectorially with the background geomagnetic field (in the absence of other sources that would perturb the ambient field) to derive characteristics of the cable that are otherwise not immediately observable. Magnetic field profiles from measurements taken along 170 survey lines were inspected visually for evidence of a distinct pattern representing the presence of the cable. Many profiles were dominated by field distortions unrelated to the cable caused by bridge structures or other submerged objects, and the cable's contribution to the field was not detectable. BB, with 40 of the survey lines, did not yield usable data for these reasons. The unrelated anomalies could be up to 100 times greater than those from the cable. In total, discernible magnetic field profiles measured from 76 survey lines were regressed against the equations, representing eight days of measurement. The modeled field anomalies due to the cable (the difference between the maximum and minimum field along the survey line at the cable crossing) were virtually identical to the measured values. The modeling

  3. Changes in causes of death among persons with AIDS: San Francisco, California, 1996-2011.

    Science.gov (United States)

    Schwarcz, Sandra K; Vu, Annie; Hsu, Ling Chin; Hessol, Nancy A

    2014-10-01

    The increased life expectancy among HIV-infected persons treated with combination antiretroviral therapy (ART), risk behaviors, and co-morbidities associated with ART place HIV-infected persons at risk for non-HIV-related causes of death. We used the San Francisco HIV/AIDS registry to identify deaths that occurred from January 1996 through December 2011. Temporal trends in AIDS- and non-AIDS-related mortality rates, the proportion of underlying and contributory causes of death, and the ratio of observed deaths in the study population to expected number of deaths among California men aged 20-79 (standardized mortality ratio [SMR]) of underlying causes of death were examined. A total of 5338 deaths were identified. The annual AIDS-related death rate (per 100 deaths) declined from 10.8 in 1996 to 0.9 in 2011 (p<0.0001), while the annual death rate from non-AIDS-related causes declined from 2.1 in 1996 to 0.9 in 2011 (p<0.0001). The proportion of deaths due to all types of heart disease combined, all non-AIDS cancers combined, mental disorders resulting from substance abuse, drug overdose, suicide and chronic obstructive pulmonary disease increased significantly over time. The SMRs for liver diseased decreased significantly over time but remained elevated. Our data highlight the importance of age-related causes of death as well as deaths from causes that are, at least in part, preventable.

  4. Selenium tissue burden compartmentalization in resident white sturgeon (Acipenser transmontanus) of the San Francisco Bay Delta estuary.

    Science.gov (United States)

    Linares-Casenave, Javier; Linville, R; Van Eenennaam, J P; Muguet, J B; Doroshov, S I

    2015-01-01

    High selenium (Se) loads in the San Francisco Bay Delta are bioaccumulated and biomagnified in food webs and can impair the reproduction of resident oviparous animals such as white sturgeon. The objective of the present study was to determine the Se tissue burden in San Francisco Bay Delta-resident white sturgeon to assess Se bioaccumulation in different organs, including ovaries and liver where egg yolk precursor proteins are synthesized. The authors obtained 54 San Francisco Bay Delta-resident white sturgeon including 26 female and 28 male subadults with immature gonads, 8 females with vitellogenic eggs, and 13 males with maturing gonads. Length, weight, age, reproductive stage of development, and kidney, liver, gonad, and muscle Se concentrations were determined in all fish. Concentrations of Se in muscle, gonads, and liver significantly increased with fish size, whereas kidney Se was not correlated to body size and was at the highest level compared with other organs. There was no difference between the sexes (p > 0.05) in Se concentrations in kidney (12.83 ± 0.51 µg · g(-1) dry wt), liver (11.85 ± 1.04 µg · g(-1) dry wt), and muscle (7.09 ± 0.52 µg · g(-1) dry wt; mean ± standard error, n = 47); but Se concentration was higher in the ovary than in testis (p = 0.04). Females with vitellogenic eggs had higher Se concentrations in the ovaries (20.77 ± 4.11 µg · g(-1) dry wt vs 5.22 ± 2.50 µg · g(-1) dry wt), liver (21.84 ± 2.07 µg · g(-1) dry wt vs 8.03 ± 1.03 µg · g(-1) dry wt), and muscle (10.18 ± 1.93 µg · g(-1) dry wt vs 5.48 ± 0.64 µg · g(-1) dry wt) compared with less advanced, previtellogenic females (p white sturgeon were comparable with levels previously shown to cause reproductive toxicity in dietary Se experiments with captive white sturgeon.

  5. Hazard-evaluation and technical-assistance report HETA 90-122-l2073, technical assistance to San Francisco General Hospital and Medical Center, San Francisco, California

    Energy Technology Data Exchange (ETDEWEB)

    Moss, C.E.; Seitz, T.

    1990-10-01

    In response to a request from the Director of the Environmental Health and Safety Department of the San Francisco General Hospital and Medical Center, located in San Francisco, California, an evaluation was undertaken of possible hazardous working conditions at that site. Concern existed about exposures to hazards while operating the germicidal lamp at the facility. Germicidal lamps were used to disinfect the air in tuberculosis and aerosolized pentamidine clinics. The workers wore no protective eye wear. All rooms used a 30 watt germicidal lamp. Lower wattage bulbs in the smaller rooms would have reduced occupational ultraviolet (UV) exposure. Reflectance levels of UV radiation were quite high and varied. Worker exposure to germicidal lamp UV levels was dependent on many factors, some of the most important ones being the position of the bulb in the room, age of the bulb, obstruction of the UV radiation by objects near the bulb, and the height of the worker. While there are no consensus guidelines available on ventilation systems designed for areas where germicidal lamps are used, the provision of good room air distribution and mixing is recommended to prevent stagnant air conditions or short circuiting of supply air within the room. Bulb changers need to be aware of the need for protective clothing and gloves for protection from both the UV radiation levels as well as possible glass breakage.

  6. Breeding density, nesting habitat, and predators of the California Clapper Rail

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — We studied the breeding density and nesting activities of the California clapper rail (Rallus longirostris obsoletus) in south San Francisco Bay between April and...

  7. Monitoring the San Francisco Bay Area Freeway Network Using Probe Vehicles and Random Access Radio Channel

    NARCIS (Netherlands)

    Linnartz, J.P.M.G.; Westerman, M.; Hamerslag, R.

    1994-01-01

    This work was performed as part of the California PATH Program of the University of California, in cooperation with the State of California Business, Transportation, and Housing Agency, Department of Transportation; and the United States Department of Transportation, Federal Highway Administration.

  8. Examination Of The Influence Of Service Quality On Membership Renewal In Fitness Centers In San Francisco Bay Area

    Directory of Open Access Journals (Sweden)

    Pei Chih Wei

    2010-12-01

    Full Text Available Corporations have to learn how to satisfy their customers’ various demands as the era of interactivity with customers has emerged (Pepper & Rogers, 1999. For fitness center, customers’ demands are increasing and diversified. Therefore, service quality is an index of quality assessment from customers for service-producing industries. Furthermore, the concept of corporate expansion and customer relationship has become the foundation of service-providers for higher profitability through customers’ renewal of membership. The main purpose of this study is to evaluate the impact of service quality on the renewal willingness of fitness center membership. Customers from four fitness centers in the San Francisco Bay Area, USA, were randomly selected for this survey. A total of 50 subjects participated in this survey. The data was analyzed by multiple regression and stepwise regression. The result indicated that the service quality has positive influence on the renewal willingness of membership.

  9. Water quality measurements in San Francisco Bay by the U.S. Geological Survey, 1969-2015.

    Science.gov (United States)

    Schraga, Tara S; Cloern, James E

    2017-08-08

    The U.S. Geological Survey (USGS) maintains a place-based research program in San Francisco Bay (USA) that began in 1969 and continues, providing one of the longest records of water-quality measurements in a North American estuary. Constituents include salinity, temperature, light extinction coefficient, and concentrations of chlorophyll-a, dissolved oxygen, suspended particulate matter, nitrate, nitrite, ammonium, silicate, and phosphate. We describe the sampling program, analytical methods, structure of the data record, and how to access all measurements made from 1969 through 2015. We provide a summary of how these data have been used by USGS and other researchers to deepen understanding of how estuaries are structured and function differently from the river and ocean ecosystems they bridge.

  10. Water quality measurements in San Francisco Bay by the U.S. Geological Survey, 1969–2015

    Science.gov (United States)

    Schraga, Tara; Cloern, James E.

    2017-01-01

    The U.S. Geological Survey (USGS) maintains a place-based research program in San Francisco Bay (USA) that began in 1969 and continues, providing one of the longest records of water-quality measurements in a North American estuary. Constituents include salinity, temperature, light extinction coefficient, and concentrations of chlorophyll-a, dissolved oxygen, suspended particulate matter, nitrate, nitrite, ammonium, silicate, and phosphate. We describe the sampling program, analytical methods, structure of the data record, and how to access all measurements made from 1969 through 2015. We provide a summary of how these data have been used by USGS and other researchers to deepen understanding of how estuaries are structured and function differently from the river and ocean ecosystems they bridge.

  11. Highest PBDE levels (max 63 ppm) yet found in biota measured in seabird eggs from San Francisco Bay

    Energy Technology Data Exchange (ETDEWEB)

    She, J.; Holden, A.; Tanner, M.; Sharp, M.; Hooper, K. [Department of Toxic Substances Control, Berkeley, CA (United States). Hazardous Materials Lab.; Adelsbach, T. [Environmental Contaminants Division, Sacramento Fish and Wildlife Office, US Fish and Wildlife Service, Sacramento, CA (United States)

    2004-09-15

    High levels of polybrominated diphenylethers (PBDEs) have been found in humans and wildlife from the San Francisco Bay Area, with levels in women among the highest in the world, and levels in piscivorous seabird eggs at the ppm level. Seabirds are useful for monitoring and assessing ecosystem health at various times and places because they occupy a high trophic level in the marine food web, are long-lived, and are generally localized near their breeding and non-breeding sites. In collaboration with the US Fish and Wildlife Services (USFWS), we are carrying out a three-year investigation of dioxin, PCB and PBDE levels in eggs from fish-eating seabirds. Year 1 (2002) PBDE measurements from 73 bird eggs were reported at Dioxin2003. Year 2 (2003) PBDE measurements from 45 samples are presented in this report. The highest PBDE level measured in eggs was 63 ppm, lipid, which is the highest PBDE level, yet reported in biota.

  12. User's guide to the LIRAQ model: an air pollution model for the San Francisco Bay Area

    Energy Technology Data Exchange (ETDEWEB)

    MacCracken, M.C.

    1975-12-19

    The Livermore Regional Air Quality (LIRAQ) model comprises a set of computer programs that have been integrated into an easily used tool for the air quality planner. To assemble and modify the necessary data files and to direct model execution, a problem formulation program has been developed that makes possible the setup of a wide variety of studies involving perturbation of the emission inventory, changes to the initial and boundary conditions, and different choices of grid size and problem domain. In addition to describing the types of air quality problems for which the LIRAQ model may be used, this User's Guide provides detailed information on how to set up and conduct model simulations. Also included are descriptions of the formats of input data files so that the LIRAQ model may be applied to regions other than the San Francisco Bay Area.

  13. Views of the Sea Floor in Northern Monterey Bay, California

    Science.gov (United States)

    Storlazzi, Curt D.; Golden, Nadine E.; Finlayson, David P.

    2008-01-01

    A sonar survey that produced unprecedented high-resolution images of the sea floor in northern Monterey Bay was conducted in 2005 and 2006. The survey, performed over 14 days by the U.S. Geological Survey (USGS), consisted of 172 tracklines and over 300 million soundings and covered an area of 12.2 km2 (4.7 mi2). The goals of this survey were to collect high-resolution bathymetry (depth to the sea floor) and acoustic backscatter data (amount of sound energy bounced back from the sea floor, which provides information on sea-floor hardness and texture) from the inner continental shelf. These data will provide a baseline for future change analyses, geologic mapping, sediment- and contaminant-transport studies, benthic-habitat delineation, and numerical modeling efforts. The survey shows that the inner shelf in this area is extremely varied in nature, encompassing flat sandy areas, faults, boulder fields, and complex bedrock ridges that support rich marine ecosystems. Furthermore, many of these complex bedrock ridges form the ?reefs? that result in a number of California?s classic surf breaks.

  14. Wastewater and Saltwater: Studying the Biogeochemistry and Microbial Activity Associated with Wastewater Inputs to San Francisco Bay

    Science.gov (United States)

    Challenor, T.; Menendez, A. D.; Damashek, J.; Francis, C. A.; Casciotti, K. L.

    2014-12-01

    Nitrification is the process of converting ammonium (NH­­4+) into nitrate (NO3-), and is a crucial step in removing nitrogen (N) from aquatic ecosystems. This process is governed by ammonia-oxidizing bacteria (AOB) and archaea (AOA) that utilize the ammonia monooxygenase gene (amoA). Studying the rates of nitrification and the abundances of ammonia-oxidizing microorganisms in south San Francisco Bay's Artesian Slough, which receives treated effluent from the massive San Jose-Santa Clara Regional Wastewater Facility, are important for understanding the cycling of nutrients in this small but complex estuary. Wastewater inputs can have negative environmental impacts, such as the release of nitrous oxide, a byproduct of nitrification and a powerful greenhouse gas. Nutrient inputs can also increase productivity and sometimes lead to oxygen depletion. Assessing the relative abundance and diversity of AOA and AOB, along with measuring nitrification rates gives vital information about the biology and biogeochemistry of this important N-cycling process. To calculate nitrification rates, water samples were spiked with 15N-labeled ammonium and incubated in triplicate for 24 hours. Four time-points were extracted across the incubation and the "denitrifier" method was used to measure the isotopic ratio of nitrate in the samples over time. In order to determine relative ratios of AOB to AOA, DNA was extracted from water samples and used in clade-specific amoA PCR assays. Nitrification rates were detectable in all locations sampled and were higher than in other regions of the bay, as were concentrations of nitrate and ammonium. Rates were highest in the regions of Artesian Slough most directly affected by wastewater effluent. AOB vastly outnumbered AOA, which is consistent with other studies showing that AOB prefer high nutrient environments. AOB diversity includes clades of Nitrosospira and Nitrosomonas prevalent in estuarine settings. Many of the sequenced genes are related

  15. From Sediment to Top Predators: Broad Exposure of Polyhalogenated Carbazoles in San Francisco Bay (U.S.A.).

    Science.gov (United States)

    Wu, Yan; Tan, Hongli; Sutton, Rebecca; Chen, Da

    2017-02-21

    The present study provides the first comprehensive investigation of polyhalogenated carbazoles (PHCZs) contamination in an aquatic ecosystem. PHCZs have been found in soil and aquatic sediment from several different regions, but knowledge of their bioaccumulation and trophodynamics is extremely scarce. This work investigated a suite of 11 PHCZ congeners in San Francisco Bay (United States) sediment and organisms, including bivalves (n = 6 composites), sport fish (n = 12 composites), harbor seal blubber (n = 18), and bird eggs (n = 8 composites). The most detectable congeners included 3,6-dichlorocarbazole (36-CCZ), 3,6-dibromocarbazole (36-BCZ), 1,3,6-tribromocarbazole (136-BCZ), 1,3,6,8-tetrabromocarbazole (1368-BCZ), and 1,8-dibromo-3,6-dichlorocarbazole (18-B-36-CCZ). The median concentrations of ΣPHCZs were 9.3 ng/g dry weight in sediment and ranged from 33.7 to 164 ng/g lipid weight in various species. Biomagnification was observed from fish to harbor seal and was mainly driven by chlorinated carbazoles, particularly 36-CCZ. Congener compositions of PHCZs differed among species, suggesting that individual congeners may be subject to different bioaccumulation or metabolism in species occupying various trophic levels in the studied aquatic system. Toxic equivalent (TEQ) values of PHCZs were determined on the basis of their relative effect potencies (REP) compared to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The median TEQ was 1.2 pg TEQ/g dry weight in sediment and 4.8-19.5 pg TEQ/g lipid weight in biological tissues. Our study demonstrated the broad exposure of PHCZs in San Francisco Bay and their characteristics of bioaccumulation and biomagnification along with dioxin-like effects. These findings raise the need for additional research to better elucidate their sources, environmental behavior, and fate in global environments.

  16. Geology and geomorphology--Offshore of Half Moon Bay Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the geologic and geomorphic map of the Offshore of Half Moon Bay map area, California. The vector data file is included in...

  17. Geology and geomorphology--Offshore of Half Moon Bay Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the geologic and geomorphic map of the Offshore of Half Moon Bay map area, California. The vector data file is included in...

  18. Confirmatory sediment analyses and solid and suspended particulate phase bioassays on sediment from Oakland Inner Harbor, San Francisco, California

    Energy Technology Data Exchange (ETDEWEB)

    Word, J.Q.; Ward, J.A.; Apts, C.W.; Woodruff, D.L.; Barrows, M.E.; Cullinan, V.I.; Hyland, J.L.; Campbell, J.F.

    1988-12-01

    The US Army Corps of Engineers (USACE), San Francisco District, was authorized by the US Congress to deepen the navigation channels of Inner and Outer Oakland Harbor, California. During review of the environmental impact statement required for this dredging and disposal project, a panel of national experts approved the open-water disposal of dredged sediment from selected areas within the Inner Harbor, subject to results of confirmatory solid phase bioassays. The San Francisco District of the Corps requested the Battle/Marine Sciences Laboratory (MSL) to conduct these confirmatory studies. The studies provided technical data for an evaluation of the potential environmental impact of this project. Within extremely narrow time constraints, these studies provided chemical and biological information required by ocean dumping regulations to determine suitability of the Oakland Inner Harbor and turning basin sediment for ocean disposal. 23 refs., 18 figs., 45 tabs.

  19. Riding the storm--landslide danger in the San Francisco Bay Area

    Science.gov (United States)

    Adams, Karen

    2007-01-01

    Movie Synopsis: --A catastrophic 1982 rainstorm triggered 18,000 landslides in the Bay Area, claiming 25 lives and causing $66 million in property damage. --The combination of steep slopes, weak rocks, and intense winter storms make Bay Area uplands an ideal setting for landslides. --Landslides include both swift, potentially deadly debris flows and slower, but destructive deepseated slides. --Learn what USGS scientists have discovered about landslide dynamics and which slopes are most susceptible to sliding. --Hear the devastating stories of Bay Area residents affected by landslides and learn to recognize the danger signs.

  20. Women of California.

    Science.gov (United States)

    Gray, Harry

    This publication points out the achievements of women who contributed to the development and history of California from the 16th century, when the Spanish Conquistadores moved westward into the San Francisco Bay area, to the gold rush of 1848, and during the following period when women helped stabilize society on the rugged frontier. Women not…

  1. Holocene paleoclimate records from a large California estuarine system and its watershed region: linking watershed climate and bay conditions

    Science.gov (United States)

    Malamud-Roam, Frances P.; Lynn Ingram, B.; Hughes, Malcolm; Florsheim, Joan L.

    2006-07-01

    The San Francisco Bay-Delta system includes a watershed that covers a large area of California and provides water to two-thirds of the State's population. Climate over the estuary and its watershed in the dry summer months is controlled by the subtropical high which dominates and deflects storms from California. The subtropical high weakens and migrates south as the Aleutian Low strengthens, bringing wet winter storms to the region. Paleoclimatic records from the Bay and its greater watershed, spanning the Holocene, are reviewed here in order to better understand natural variations of precipitation and runoff and the linkages between those variations and the salinity and ecosystems of the estuary. To better understand regional-scale climate patterns, paleoclimate records from coastal California and the Great Basin are also considered. Large fluctuations in climate have occurred during the period of interest, and there is generally good agreement between the paleoclimate records from different regions. Early Holocene climate throughout California was marked by rising temperatures and reduced moisture as seen in fire records from the watershed. This warmth and aridity peaked about 5000-7000 years ago and was followed by a cooling trend, with variable moisture conditions. The Estuary formed relatively rapidly in response to a high rate of sea level rise that dominated the Holocene until about 6000 years ago, and the subsequent reduced rate of inundation allowed vast tidal marshes to form along the edges of the estuary, which have since been recording changes in environmental conditions. The impacts of changing regional climate patterns are experienced in the San Francisco Bay-Delta system, as altered fresh water flows result in altered estuary salinity. For example, approximately 3800 cal yr B.P., records from throughout the state indicate a cool, moist period, and Bay salinity was reduced; this period was followed by a general drying trend throughout California over

  2. Integrating terrestrial LiDAR and stereo photogrammetry to map the Tolay lakebed in northern San Francisco Bay

    Science.gov (United States)

    Woo, Isa; Storesund,; Takekawa, John Y.; Gardiner, Rachel J.; Ehret,

    2009-01-01

    The Tolay Creek Watershed drains approximately 3,520 ha along the northern edge of San Francisco Bay. Surrounded by a mosaic of open space conservation easements and public wildlife areas, it is one of the only watersheds in this urbanized estuary that is protected from its headwaters to the bay. Tolay Lake is a seasonal, spring-fed lake found in the upper watershed that historically extended over 120 ha. Although the lakebed was farmed since the early 1860s, the majority of the lakebed was recently acquired by the Sonoma County Regional Parks Department to restore its natural habitat values. As part of the restoration planning process, we produced a digital elevation model (DEM) of the historic extent of Tolay Lake by integrating terrestrial LiDAR (light detection and ranging) and stereo photogrammetry datasets, and real-time kinematic (RTK) global positioning system (GPS) surveys. We integrated the data, generated a DEM of the lakebed and upland areas, and analyzed errors. The accuracy of the composite DEM was verified using spot elevations obtained from the RTK GPS. Thus, we found that by combining photogrammetry, terrestrial LiDAR, and RTK GPS, we created an accurate baseline elevation map to use in watershed restoration planning and design.

  3. University of California San Francisco (UCSF-1): Chemical-Genetic Interaction Mapping Strategy | Office of Cancer Genomics

    Science.gov (United States)

    The CTD2 Center at University of California San Francisco (UCSF-1) developed a chemical-genetic interaction mapping strategy to uncover the impact of cancer gene expression on responses to a panel of emerging therapeutics. To study the impact of aberrant gene activity in isolation, they developed an isogenic model of triple-negative breast cancer (TNBC) using the hormone receptor negative MCF10A non-tumorigenic cell line derived from healthy breast tissue which is diploid and largely devoid of somatic alterations.

  4. Calibration and evaluation of five indicators of benthic community condition in two California bay and estuary habitats.

    Science.gov (United States)

    Ranasinghe, J Ananda; Weisberg, Stephen B; Smith, Robert W; Montagne, David E; Thompson, Bruce; Oakden, James M; Huff, David D; Cadien, Donald B; Velarde, Ronald G; Ritter, Kerry J

    2009-01-01

    Many types of indices have been developed to assess benthic invertebrate community condition, but there have been few studies evaluating the relative performance of different index approaches. Here we calibrate and compare the performance of five indices: the Benthic Response Index (BRI), Benthic Quality Index (BQI), Relative Benthic Index (RBI), River Invertebrate Prediction and Classification System (RIVPACS), and the Index of Biotic Integrity (IBI). We also examine whether index performance improves when the different indices, which rely on measurement of different properties, are used in combination. The five indices were calibrated for two geographies using 238 samples from southern California marine bays and 125 samples from polyhaline San Francisco Bay. Index performance was evaluated by comparing index assessments of 35 sites to the best professional judgment of nine benthic experts. None of the individual indices performed as well as the average expert in ranking sample condition or evaluating whether benthic assemblages exhibited evidence of disturbance. However, several index combinations outperformed the average expert. When results from both habitats were combined, two four-index combinations and a three-index combination performed best. However, performance differences among several combinations were small enough that factors such as logistics can also become a consideration in index selection.

  5. Impacts of representing sea-level rise uncertainty on future flood risks: An example from San Francisco Bay.

    Science.gov (United States)

    Ruckert, Kelsey L; Oddo, Perry C; Keller, Klaus

    2017-01-01

    Rising sea levels increase the probability of future coastal flooding. Many decision-makers use risk analyses to inform the design of sea-level rise (SLR) adaptation strategies. These analyses are often silent on potentially relevant uncertainties. For example, some previous risk analyses use the expected, best, or large quantile (i.e., 90%) estimate of future SLR. Here, we use a case study to quantify and illustrate how neglecting SLR uncertainties can bias risk projections. Specifically, we focus on the future 100-yr (1% annual exceedance probability) coastal flood height (storm surge including SLR) in the year 2100 in the San Francisco Bay area. We find that accounting for uncertainty in future SLR increases the return level (the height associated with a probability of occurrence) by half a meter from roughly 2.2 to 2.7 m, compared to using the mean sea-level projection. Accounting for this uncertainty also changes the shape of the relationship between the return period (the inverse probability that an event of interest will occur) and the return level. For instance, incorporating uncertainties shortens the return period associated with the 2.2 m return level from a 100-yr to roughly a 7-yr return period (∼15% probability). Additionally, accounting for this uncertainty doubles the area at risk of flooding (the area to be flooded under a certain height; e.g., the 100-yr flood height) in San Francisco. These results indicate that the method of accounting for future SLR can have considerable impacts on the design of flood risk management strategies.

  6. Impacts of representing sea-level rise uncertainty on future flood risks: An example from San Francisco Bay

    Science.gov (United States)

    Oddo, Perry C.; Keller, Klaus

    2017-01-01

    Rising sea levels increase the probability of future coastal flooding. Many decision-makers use risk analyses to inform the design of sea-level rise (SLR) adaptation strategies. These analyses are often silent on potentially relevant uncertainties. For example, some previous risk analyses use the expected, best, or large quantile (i.e., 90%) estimate of future SLR. Here, we use a case study to quantify and illustrate how neglecting SLR uncertainties can bias risk projections. Specifically, we focus on the future 100-yr (1% annual exceedance probability) coastal flood height (storm surge including SLR) in the year 2100 in the San Francisco Bay area. We find that accounting for uncertainty in future SLR increases the return level (the height associated with a probability of occurrence) by half a meter from roughly 2.2 to 2.7 m, compared to using the mean sea-level projection. Accounting for this uncertainty also changes the shape of the relationship between the return period (the inverse probability that an event of interest will occur) and the return level. For instance, incorporating uncertainties shortens the return period associated with the 2.2 m return level from a 100-yr to roughly a 7-yr return period (∼15% probability). Additionally, accounting for this uncertainty doubles the area at risk of flooding (the area to be flooded under a certain height; e.g., the 100-yr flood height) in San Francisco. These results indicate that the method of accounting for future SLR can have considerable impacts on the design of flood risk management strategies. PMID:28350884

  7. Inter-station correlations of ozone concentrations in the San Francisco Bay area

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, C

    1979-05-01

    This project was undertaken primarily to show how one might use SPSS (Statistical Package for the Social Sciences) to analyze air pollution data. As an example, an examination was made of the ozone concentration correlation coefficients between the 25 BAAPCD's (Bay Area Air Pollution Control Districts) for the months of July, August and September 1978.

  8. Polycyclic aromatic hydrocarbon body residues and lysosomal membrane destabilization in mussels exposed to the Dubai Star bunker fuel oil (intermediate fuel oil 380) spill in San Francisco Bay.

    Science.gov (United States)

    Hwang, Hyun-Min; Stanton, Beckye; McBride, Toby; Anderson, Michael J

    2014-05-01

    Following the spill of bunker fuel oil (intermediate fuel oil 380, approximately 1500-3000 L) into San Francisco Bay in October 2009, polycyclic aromatic hydrocarbon (PAH) concentrations in mussels from moderately oiled areas increased up to 87 554 ng/g (dry wt) and, 3 mo later, decreased to concentrations found in mussels collected prior to oiling, with a biological half-life of approximately 16 d. Lysosomal membrane destabilization increased in mussels with higher PAH body burdens.

  9. Distribution of mercury in surficial sediments from Todos Santos Bay, Baja California, México.

    Science.gov (United States)

    Gutiérrez-Galindo, E A; Casas-Beltrán, D A; Muñoz-Barbosa, A; Daesslé, L W; Segovia-Zavala, J A; Macías-Zamora, J V; Orozco-Borbón, M V

    2008-02-01

    During 2004 the spatial distribution of total Hg in sediments from Todos Santos Bay, Baja California, México was studied to evaluate the degree of environmental impact in this bay. The results showed low concentrations and no Hg enrichment at any site. These findings suggest natural levels of Hg in the water of Todos Santos Bay. The regional distribution of Hg/Fe shows lower values in the East and higher in the West of the bay. No significant correlations (p<0.05) were found between Hg and organic matter or particle size, suggesting that the distribution of Hg is not controlled by these variables.

  10. Integration of bed characteristics, geochemical tracers, current measurements, and numerical modeling for assessing the provenance of beach sand in the San Francisco Bay Coastal System

    Science.gov (United States)

    Barnard, Patrick L.; Foxgrover, Amy C.; Elias, Edwin P.L.; Erikson, Li H.; Hein, James R.; McGann, Mary; Mizell, Kira; Rosenbauer, Robert J.; Swarzenski, Peter W.; Takesue, Renee K.; Wong, Florence L.; Woodrow, Donald L.; Barnard, P.L.; Jaffee, B.E.; Schoellhamer, D.H.

    2013-01-01

    Over 150 million m3 of sand-sized sediment has disappeared from the central region of the San Francisco Bay Coastal System during the last half century. This enormous loss may reflect numerous anthropogenic influences, such as watershed damming, bay-fill development, aggregate mining, and dredging. The reduction in Bay sediment also appears to be linked to a reduction in sediment supply and recent widespread erosion of adjacent beaches, wetlands, and submarine environments. A unique, multi-faceted provenance study was performed to definitively establish the primary sources, sinks, and transport pathways of beach-sized sand in the region, thereby identifying the activities and processes that directly limit supply to the outer coast. This integrative program is based on comprehensive surficial sediment sampling of the San Francisco Bay Coastal System, including the seabed, Bay floor, area beaches, adjacent rock units, and major drainages. Analyses of sample morphometrics and biological composition (e.g., Foraminifera) were then integrated with a suite of tracers including 87Sr/86Sr and 143Nd/144Nd isotopes, rare earth elements, semi-quantitative X-ray diffraction mineralogy, and heavy minerals, and with process-based numerical modeling, in situ current measurements, and bedform asymmetry to robustly determine the provenance of beach-sized sand in the region.

  11. Rainfall Estimation and Performance Characterization Using an X-band Dual-Polarization Radar in the San Francisco Bay Area

    Science.gov (United States)

    Cifelli, R.; Chen, H.; Chandra, C. V.

    2016-12-01

    The San Francisco Bay area is home to over 5 million people. In February 2016, the area also hosted the NFL Super bowl, bringing additional people and focusing national attention to the region. Based on the El Nino forecast, public officials expressed concern for heavy rainfall and flooding with the potential for threats to public safety, costly flood damage to infrastructure, negative impacts to water quality (e.g., combined sewer overflows) and major disruptions in transportation. Mitigation of the negative impacts listed above requires accurate precipitation monitoring (quantitative precipitation estimation-QPE) and prediction (including radar nowcasting). The proximity to terrain and maritime conditions as well as the siting of existing NEXRAD radars are all challenges in providing accurate, short-term near surface rainfall estimates in the Bay area urban region. As part of a collaborative effort between the National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory, Colorado State University (CSU), and Santa Clara Valley Water District (SCVWD), an X-band dual-polarization radar was deployed in Santa Clara Valley in February of 2016 to provide support for the National Weather Service during the Super Bowl and NOAA's El Nino Rapid Response field campaign. This high-resolution radar was deployed on the roof of one of the buildings at the Penitencia Water Treatment Plant. The main goal was to provide detailed precipitation information for use in weather forecasting and assists the water district in their ability to predict rainfall and streamflow with real-time rainfall data over Santa Clara County especially during a potentially large El Nino year. The following figure shows the radar's coverage map, as well as sample reflectivity observations on March 06, 2016, at 00:04UTC. This paper presents results from a pilot study from February, 2016 to May, 2016 demonstrating the use of X-band weather radar for quantitative precipitation

  12. 40 CFR 81.21 - San Francisco Bay Area Intrastate Air Quality Control Region.

    Science.gov (United States)

    2010-07-01

    ... Counties, California; thence running northerly along the easterly boundary line of said Rancho Estero... easterly to its intersection with the easterly line of Graton Road; thence running along the easterly and southerly line of Graton Road, northerly and easterly to its intersection with the easterly line of...

  13. Interim Use Limitations for Eleven Threatened or Endangered Species in the San Francisco Bay Area

    Science.gov (United States)

    Interim use limitations may apply to pesticide products containing any of 75 active ingredients, in 8 listed counties. The limitations are in a Stipulated Injunction entered by the U.S. District Court for the Northern District of California in 2010.

  14. Ecosystem variability along the estuarine salinity gradient: Examples from long-term study of San Francisco Bay

    Science.gov (United States)

    Cloern, James E.; Jassby, Alan D.; Schraga, Tara; Kress, Erica S.; Martin, Charles A.

    2017-01-01

    The salinity gradient of estuaries plays a unique and fundamental role in structuring spatial patterns of physical properties, biota, and biogeochemical processes. We use variability along the salinity gradient of San Francisco Bay to illustrate some lessons about the diversity of spatial structures in estuaries and their variability over time. Spatial patterns of dissolved constituents (e.g., silicate) can be linear or nonlinear, depending on the relative importance of river-ocean mixing and internal sinks (diatom uptake). Particles have different spatial patterns because they accumulate in estuarine turbidity maxima formed by the combination of sinking and estuarine circulation. Some constituents have weak or no mean spatial structure along the salinity gradient, reflecting spatially distributed sources along the estuary (nitrate) or atmospheric exchanges that buffer spatial variability of ecosystem metabolism (dissolved oxygen). The density difference between freshwater and seawater establishes stratification in estuaries stronger than the thermal stratification of lakes and oceans. Stratification is strongest around the center of the salinity gradient and when river discharge is high. Spatial distributions of motile organisms are shaped by species-specific adaptations to different salinity ranges (shrimp) and by behavioral responses to environmental variability (northern anchovy). Estuarine spatial patterns change over time scales of events (intrusions of upwelled ocean water), seasons (river inflow), years (annual weather anomalies), and between eras separated by ecosystem disturbances (a species introduction). Each of these lessons is a piece in the puzzle of how estuarine ecosystems are structured and how they differ from the river and ocean ecosystems they bridge.

  15. The Conservation Contributions of Conservation Easements: Analysis of the San Francisco Bay Area Protected Lands Spatial Database

    Directory of Open Access Journals (Sweden)

    Adena R. Rissman

    2008-06-01

    Full Text Available Conservation easements have emerged as an important tool for land trusts and government agencies aiming to conserve private land in the United States. Despite the increase in public investment in conservation easement acquisitions, little is known about their conservation outcomes, particularly at a landscape scale. The nine-county San Francisco Bay Area exemplifies a complex conservation context: 190 organizations hold 24% of the land base in some type of protection status. Using a detailed protected lands database, we compared the contributions of conservation easements and fee-simple protected areas to ecological, agricultural, and public recreation benefits. We found that conservation easements were more likely to conserve grasslands, oak woodlands, and agricultural land, whereas fee-simple properties were more likely to conserve chaparral and scrub, redwoods, and urban areas. Conservation easements contributed to open space connectivity but were unlikely to be integrated into local land-use plans or provide public recreation. In particular, properties held by land trusts were less likely to allow for public recreation than were public lands. Conservation easements held by land trusts and special districts complemented fee-simple lands and provided greater conservation of some ecological communities and agricultural lands than fee-simple properties. Spatial databases of protected areas that include conservation easements are necessary for conservation planning and assessment.

  16. Obesity and survival in population-based patients with pancreatic cancer in the San Francisco Bay Area.

    Science.gov (United States)

    Gong, Zhihong; Holly, Elizabeth A; Bracci, Paige M

    2012-12-01

    Obesity has been consistently associated with increased risk of pancreatic cancer incidence and mortality. However, studies of obesity and overall survival in patients with pancreatic cancer are notably lacking, especially in population-based studies. Active and passive follow-up were used to determine vital status and survival for 510 pancreatic cancer patients diagnosed from 1995 to 1999 in a large population-based case-control study in the San Francisco Bay Area. Survival rates were computed using Kaplan-Meier methods. Hazard ratios (HR) and 95 % confidence intervals (CI) were estimated in multivariable Cox proportional hazards models as measures of the association between pre-diagnostic obesity and pancreatic cancer survival. An elevated hazard ratio of 1.3 (95 % CI, 0.91-1.81) was observed for obese [body mass index (BMI) ≥ 30] compared with normal range BMI (obese compared with normal BMI patients [localized disease at diagnosis (HR, 3.1), surgical resection (HR, 1.6), ever smokers (HR, 1.6), diabetics (HR, 3.3)]. Poor survival was observed among men, older patients, more recent and current smokers, whereas improved survival was observed for Asian/Pacific Islanders. Our results in general provide limited support for an association between pre-diagnostic obesity and decreased survival in patients with pancreatic cancer. Patterns of reduced survival associated with obesity in some patient subgroups could be due to chance and require assessment in larger pooled studies.

  17. Landscape scale vegetation-type conversion and fire hazard in the San Francisco bay area open spaces

    Science.gov (United States)

    Russell, W.H.; McBride, J.R.

    2003-01-01

    Successional pressures resulting from fire suppression and reduced grazing have resulted in vegetation-type conversion in the open spaces surrounding the urbanized areas of the San Francisco bay area. Coverage of various vegetation types were sampled on seven sites using a chronosequence of remote images in order to measure change over time. Results suggest a significant conversion of grassland to shrubland dominated by Baccharis pilularison five of the seven sites sampled. An increase in Pseudotsuga menziesii coverage was also measured on the sites where it was present. Increases fuel and fire hazard were determined through field sampling and use of the FARSITE fire area simulator. A significant increase in biomass resulting from succession of grass-dominated to shrub-dominated communities was evident. In addition, results from the FARSITE simulations indicated significantly higher fire-line intensity, and flame length associated with shrublands over all other vegetation types sampled. These results indicate that the replacement of grass dominated with shrub-dominated landscapes has increased the probability of high intensity fires. ?? 2003 Elsevier Science B.V. All rights reserved.

  18. Geochemical fine-sediment tracers in San Francisco Bay and its outer coast: the role of local watersheds

    Science.gov (United States)

    Takesue, R. K.; Barnard, P. L.

    2012-12-01

    Sediment enters San Francisco Bay (SFB) through the Sacramento-San Joaquin River Delta, the Golden Gate, and local watersheds. Inputs from local watersheds have become increasingly important since the 1940s when large-scale impoundments began upstream of the Delta. The goals of this study are to determine whether fine sediment from local watersheds have distinct geochemical signatures, and if these can be used to determine whether locally-derived sediment accumulates in SFB. Retention of fine sediment is essential if accretion of shallow and intertidal habitats is to keep pace with sea level rise. Total contents of chromium (Cr), lanthanum (La), thorium (Th), zirconium (Zr), rare earth elements (REE), and twenty five other elements were determined by ICP-MS in the fine or "mud" fraction (<63 μm) of river, tributary, bay, and outer coast bed sediment. SFB and outer coast sediment was collected in January 2012 after a 5-day storm. River and tributary sediment was collected between 2010-2012. REE contents were normalized to a shale composite (NASC). In comparison to granitic material from the Sierra Nevada, local watersheds contain ultramafic Franciscan rocks in the Coast Range, volcanic deposits near Napa and Sonoma, and ancient marine sedimentary rocks. Fine sediment from the Sacramento River was enriched in heavy REE (HREENASC) and Cr, while that from the San Joaquin River was enriched in light REE (LREENASC) and Th. Petaluma River and Sonoma Creek fine sediments were distinguished by middle REE (MREENASC) enrichments and low Cr contents consistent with felsic volcanic rocks. In contrast, fine sediments in Napa River and Wildcat Creek had relatively flat REENASC patterns and intermediate to high Cr contents that suggest a Franciscan influence. The same was true for fine sediment in Marin creeks (Arroyo del Presidio and Corte Madera) and two South Bay tributaries (Guadelupe River and San Francisquito Creek). San Francisquito Creek fine sediment was uniquely

  19. Proceedings of the Second Life Education Workshop, Part of the Second Life Community Convention (1st, San Francisco, California, August 18-20, 2006)

    Science.gov (United States)

    Livingstone, Daniel, Ed.; Kemp, Jeremy, Ed.

    2006-01-01

    This document is a compilation of 14 papers from presentations and posters of the Second Life Education Workshop at the Second Life Community Convention, presented at the Fort Mason Centre in San Francisco, California in August 2006. Following a foreword (John Bransford and Drue Gawel); preface (John Lester); and word from the chairs (Daniel…

  20. California State Waters Map Series--Offshore of San Francisco Web Services

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of...

  1. California State Waters Map Series--Offshore of San Francisco Web Services

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of...

  2. Novel analyses of long-term data provide a scientific basis for chlorophyll-a thresholds in San Francisco Bay

    Science.gov (United States)

    Sutula, Martha; Kudela, Raphael; Hagy, James D.; Harding, Lawrence W.; Senn, David; Cloern, James E.; Bricker, Suzanne B.; Beck, Marcus W.; Berg, Gry Mine

    2017-01-01

    San Francisco Bay (SFB), USA, is highly enriched in nitrogen and phosphorus, but has been resistant to the classic symptoms of eutrophication associated with over-production of phytoplankton. Observations in recent years suggest that this resistance may be weakening, shown by: significant increases of chlorophyll-a (chl-a) and decreases of dissolved oxygen (DO), common occurrences of phytoplankton taxa that can form Harmful Algal Blooms (HAB), and algal toxins in water and mussels reaching levels of concern. As a result, managers now ask: what levels of chl-a in SFB constitute tipping points of phytoplankton biomass beyond which water quality will become degraded, requiring significant nutrient reductions to avoid impairments? We analyzed data for DO, phytoplankton species composition, chl-a, and algal toxins to derive quantitative relationships between three indicators (HAB abundance, toxin concentrations, DO) and chl-a. Quantile regressions relating HAB abundance and DO to chl-a were significant, indicating SFB is at increased risk of adverse HAB and low DO levels if chl-a continues to increase. Conditional probability analysis (CPA) showed chl-a of 13 mg m−3 as a “protective” threshold below which probabilities for exceeding alert levels for HAB abundance and toxins were reduced. This threshold was similar to chl-a of 13–16 mg m−3 that would meet a SFB-wide 80% saturation Water Quality Criterion (WQC) for DO. Higher “at risk” chl-a thresholds from 25 to 40 mg m−3 corresponded to 0.5 probability of exceeding alert levels for HAB abundance, and for DO below a WQC of 5.0 mg L−1 designated for lower South Bay (LSB) and South Bay (SB). We submit these thresholds as a basis to assess eutrophication status of SFB and to inform nutrient management actions. This approach is transferrable to other estuaries to derive chl-a thresholds protective against eutrophication.

  3. Bilingual Experience in the Hungarian and German Immigrant Communities of the San Francisco Bay Area

    Directory of Open Access Journals (Sweden)

    Gergely Tóth

    2012-01-01

    Full Text Available Studies on the interaction of languages are gaining importance in today’s world, characterized by accelerated migration and increasing cultural exchange. Unlike most research in this field, which concentrate on one embedded language against a matrix language, this fieldwork-based study examines the linguistic life in two immigrant populations, Hungarian and German, against the background of English. The primary focus of this article is the description of the bilingual and bicultural experience of the two groups. The discussion of language and identity will take a central place in the paper, and diglossia, bilingualism, loyalty, and language as social behavior will also be touched upon (section 4. This is complemented by a socio-historical portrayal of these speech communities of San Francisco, set forth in the preceding section 3. Section 5 provides an outline of the informant sets, spanning three generations in each linguistic cohort, and illustrates the subjects’ attitude towards maintenance. The final, sixth section offers qualitative and quantitative comparative statements about the results of linguistic interference and the ongoing attrition process, thus contributing to our understanding of contact linguistic mechanisms, and shedding light on specific grammatical and lexical features that are most prone to attritional forces.

  4. California State Waters Map Series--Drakes Bay Web Services

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of...

  5. California State Waters Map Series--Drakes Bay Web Services

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of...

  6. 33 CFR 165.T11-304 - Safety zone; Sea World Summer Nights Fireworks; Mission Bay, San Diego, California.

    Science.gov (United States)

    2010-07-01

    ... Nights Fireworks; Mission Bay, San Diego, California. 165.T11-304 Section 165.T11-304 Navigation and...; Mission Bay, San Diego, California. (a) Location. The limits of the safety zone will include a 600 foot... prohibited unless authorized by the Captain of the Port of San Diego or his designated on-scene...

  7. Discriminatory Employment of Asian Americans; Private Industry in the San Francisco-Oakland SMSA.

    Science.gov (United States)

    Cabezas, Amado Y.; Yee, Harold T.

    The study reported on in this document investigates discriminatory employment victimizing Asian Americans in the private sector in the San Francisco, California, Bay Area. The analytical framework utilized is described in detail. Findings are presented in both statistical and discussion form, and are broken down by industry. Disparities in…

  8. Project EXCEL: San Francisco Hilton and Towers, Stewarding Department. English Communication, Module 1.

    Science.gov (United States)

    Career Resources Development Center, Inc., San Francisco, CA.

    Project EXCEL is a federally-funded workplace literacy program involving hotel enterprises in the San Francisco (California) Bay area. Its focus is on identification and instruction of literacy skills essential to job success for limited-English-proficient (LEP) workers. Training is intended to enable employees to understand written work orders,…

  9. Association of mercury and selenium with altered glutathione metabolism and oxidative stress in diving ducks from the San Francisco Bay region

    Science.gov (United States)

    Hoffman, D.J.; Ohlendorf, H.M.; Marn, C.M.; Pendleton, G.W.

    1998-01-01

    Adult male greater scaup (Aythya marila) (GS), surf scoters (Melanitta perspicillata)(SS), and ruddy ducks (Oxyura jamaicensis) (RD) were collected from Suisun Bay and coastal Tomales Bay in the greater San Francisco Bay area to assess exposure to inorganic contaminants. Hepatic selenium (Se) concentrations were highest in GS (geometric mean = 67 ppm, dw) and SS (119 ppm) in Suisun Bay, whereas hepatic mercury (Hg) was highest (19 ppm) in GS and SS from Tomales Bay. Hepatic Se and Hg were lower in RD and did not differ between locations. Hepatic supernatants were assayed for enzymes related to glutathione metabolism and antioxidant activity including: glucose-6-phosphate dehydrogenase (G-6-PDH), glutathione peroxidase (GSH-peroxidase), glutathione reductase (GSSG-reductase), and glutathione-S-transferase (GSH-transferase). GSH-peroxidase activity was higher in SS and RD, and G-6-PDH higher in GS and SS from Suisun Bay than Tomales Bay. GSSG-reductase was higher in SS from Suisun Bay. The ratio of oxidized glutathione (GSSG) to reduced glutathione (GSH) was greater in all species from Tomales Bay. The following significant relationships were found in one or more species with increasing hepatic Hg concentration: lower body, liver and heart weights; decreased hepatic GSH concentration, G-6-PDH and GSH-peroxidase activities; increased ratio of GSSG to GSH, and increased GSSG-reductase activity. With increasing hepatic Se concentration, GSH-peroxidase increased but GSH decreased. It is concluded that measurement of associated enzymes in conjunction with thiol status may be a useful bioindicator to discriminate between Hg and Se effects. Concentrations of mercury and selenium and variable affected have been associated with adverse effects on reproduction and neurological function in experimental studies with mallards.

  10. The kinematics of faults in the San Francisco Bay area inferred from geodetic and seismic data

    Science.gov (United States)

    Schmidt, David Andrew

    2002-01-01

    The work presented in this dissertation focuses on the kinematics and mechanics of the Hayward fault, the Loma Prieta earthquake rupture, and the Silver Creek fault. To better understand their behavior and geometry, geodetic and seismic data are used in conjunction with elastic models of the crust. Along the northern and central segments of the Hayward fault, a steady interseismic deformation rate is observed. Variations in this rate along strike suggest a variable slip-rate distribution at depth indicative of locked and creeping patches. A locked patch that correlates with the presumed source region of the 1868 earthquake on the Hayward fault implies that elastic strain is accumulating at this location. The southern Hayward fault exhibits complex time-dependent slip. Interferometric Synthetic Aperture Radar (InSAR) is employed to visualize the crustal deformation signal by utilizing over 100 interferograms. Results suggest that the observed surface deformation is best explained by a combination of transient fault slip and land subsidence. This is in contrast to the Silver Creek fault in the Santa Clara Valley where all of the deformation is attributed to differential aquifer compaction and expansion across the fault. Regional faults interact through the redistribution of stress in the crust and upper mantle. The effect of this change in stress on the creeping portion of the Hayward fault following the 1906 San Francisco earthquake is explored using a rate-and-state friction model. The predicted surface creep response, driven by the postseismic relaxation of the mantle following the 1906 event, is used to constrain the rheology of the lower crust. Rheologies that include a horizontal shear zone underpredict the surface creep response observed from offset cultural features. Inversions for the coseismic slip distribution of the 1989 Loma Prieta earthquake are performed to evaluate the sensitivity of the inversion to the prescribed fault geometry. Models the

  11. Application of microtremor array measurements to delineate S-wave velocity structures in San Francisco Bay Area

    Science.gov (United States)

    Hayashi, K.; Underwood, D.

    2012-12-01

    Microtremor array measurements and three-component microtremor measurements have been performed at four sites in the South Bay of the San Francisco Bay Area (Figure 1). Two seismographs with three-component accelerometers were used for data acquisition. At each site, one seismograph was fixed in one place and data was acquired at that location for the entire survey. Data was acquired by a second seismograph at larger separations ranging from 5 to 4125m from the fixed seismograph. Data acquisition was repeated at each new separation. In each measurement, 10 to 60 minutes of ambient noise was recorded. As the separations of seismographs increased, the record length of ambient noise was increased. The sampling interval used was 10msec. Entire measurements at one site took several hours. Data acquisition was performed in the day-time and the seismographs were placed in relatively quiet places such as in parks or residential areas. A spatial autocorrelation was used for calculating phase velocity and clear dispersion curves were obtained in frequency range from 0.2 to 10 Hz. A joint inversion was applied to the observed dispersion curves, and H/V spectra, and S-wave velocity models were analyzed for four sites. In the inversion, phase velocities of the dispersion curves and the absolute value and peak frequencies of the H/V spectra were used as observation data. The unknown parameters were layer thickness and S-wave velocity. A Genetic Algorithm was used for optimization. Theoretical H/V spectra and phase velocities are generated by calculating the weighted average of the fundamental mode and higher modes (up to the 5th mode) based on medium response. Figure 2 shows comparison of S-wave velocity models obtained by the inversion. We can see that a low velocity layer with S-wave velocity lower than 400m/s exists between depths of 50 to 100m at all sites. Intermediate bedrock with S-wave velocity higher than 1000m/s exists between depths of 500 to 1000m. Deepest bedrock

  12. Mudflat morphodynamics and the impact of sea level rise in South San Francisco Bay

    Science.gov (United States)

    Van der Wegen, Mick; Jaffe, Bruce E.; Foxgrover, Amy; Roelvink, Dano

    2017-01-01

    Estuarine tidal mudflats form unique habitats and maintain valuable ecosystems. Historic measurements of a mudflat in San Fancsico Bay over the past 150 years suggest the development of a rather stable mudflat profile. This raises questions on its origin and governing processes as well as on the mudflats’ fate under scenarios of sea level rise and decreasing sediment supply. We developed a 1D morphodynamic profile model (Delft3D) that is able to reproduce the 2011 measured mudflat profile. The main, schematised, forcings of the model are a constant tidal cycle and constant wave action. The model shows that wave action suspends sediment that is transported landward during flood. A depositional front moves landward until landward bed levels are high enough to carry an equal amount of sediment back during ebb. This implies that, similar to observations, the critical shear stress for erosion is regularly exceeded during the tidal cycle and that modelled equilibrium conditions include high suspended sediment concentrations at the mudflat. Shear stresses are highest during low water, while shear stresses are lower than critical (and highest at the landward end) along the mudflat during high water. Scenarios of sea level rise and decreasing sediment supply drown the mudflat. In addition, the mudflat becomes more prone to channel incision because landward accumulation is hampered. This research suggests that sea level rise is a serious threat to the presence of many estuarine intertidal mudflats, adjacent salt marshes and their associated ecological values.

  13. How can climate change and engineered water conveyance affect sediment dynamics in the San Francisco Bay-Delta system?

    Science.gov (United States)

    Achete, Fernanda; Van der Wegen, Mick; Roelvink, Jan Adriaan; Jaffe, Bruce E.

    2017-01-01

    Suspended sediment concentration is an important estuarine health indicator. Estuarine ecosystems rely on the maintenance of habitat conditions, which are changing due to direct human impact and climate change. This study aims to evaluate the impact of climate change relative to engineering measures on estuarine fine sediment dynamics and sediment budgets. We use the highly engineered San Francisco Bay-Delta system as a case study. We apply a process-based modeling approach (Delft3D-FM) to assess the changes in hydrodynamics and sediment dynamics resulting from climate change and engineering scenarios. The scenarios consider a direct human impact (shift in water pumping location), climate change (sea level rise and suspended sediment concentration decrease), and abrupt disasters (island flooding, possibly as the results of an earthquake). Levee failure has the largest impact on the hydrodynamics of the system. Reduction in sediment input from the watershed has the greatest impact on turbidity levels, which are key to primary production and define habitat conditions for endemic species. Sea level rise leads to more sediment suspension and a net sediment export if little room for accommodation is left in the system due to continuous engineering works. Mitigation measures like levee reinforcement are effective for addressing direct human impacts, but less effective for a persistent, widespread, and increasing threat like sea level rise. Progressive adaptive mitigation measures to the changes in sediment and flow dynamics resulting from sea level rise may be a more effective strategy. Our approach shows that a validated process-based model is a useful tool to address long-term (decades to centuries) changes in sediment dynamics in highly engineered estuarine systems. In addition, our modeling approach provides a useful basis for long-term, process-based studies addressing ecosystem dynamics and health.

  14. Trajectory of early tidal marsh restoration: elevation, sedimentation and colonization of breached salt ponds in the northern San Francisco Bay

    Science.gov (United States)

    Brand, L. Arriana; Smith, Lacy M.; Takekawa, John Y.; Athearn, Nicole D.; Taylor, Karen; Shellenbarger, Gregory; Schoellhamer, David H.; Spenst, Renee

    2012-01-01

    Tidal marsh restoration projects that cover large areas are critical for maintaining target species, yet few large sites have been studied and their restoration trajectories remain uncertain. A tidal marsh restoration project in the northern San Francisco Bay consisting of three breached salt ponds (≥300 ha each; 1175 ha total) is one of the largest on the west coast of North America. These diked sites were subsided and required extensive sedimentation for vegetation colonization, yet it was unclear whether they would accrete sediment and vegetate within a reasonable timeframe. We conducted bathymetric surveys to map substrate elevations using digital elevation models and surveyed colonizing Pacific cordgrass (Spartina foliosa). The average elevation of Pond 3 was 0.96 ± 0.19 m (mean ± SD; meters NAVD88) in 2005. In 2008–2009, average pond elevations were 1.05 ± 0.25 m in Pond 3, 0.81 ± 0.26 m in Pond 4, and 0.84 ± 0.24 m in Pond 5 (means ± SD; meters NAVD88). The largest site (Pond 3; 508 ha) accreted 9.5 ± 0.2 cm (mean ± SD) over 4 years, but accretion varied spatially and ranged from sediment loss in borrow ditches and adjacent to an unplanned, early breach to sediment gains up to 33 cm in more sheltered regions. The mean elevation of colonizing S. foliosa varied by pond (F = 71.20, df = 84, P S. foliosa. Our results suggest that sedimentation to elevations that enable vegetation colonization is feasible in large sites with sufficient sediment loads although may occur more slowly compared with smaller sites.

  15. Gas exchange rates across the sediment-water and air-water interfaces in south San Francisco Bay

    Science.gov (United States)

    Hartman, Blayne; Hammond, Douglas E.

    1984-01-01

    Radon 222 concentrations in the water and sedimentary columns and radon exchange rates across the sediment-water and air-water interfaces have been measured in a section of south San Francisco Bay. Two independent methods have been used to determine sediment-water exchange rates, and the annual averages of these methods agree within the uncertainty of the determinations, about 20%. The annual average of benthic fluxes from shoal areas is nearly a factor of 2 greater than fluxes from the channel areas. Fluxes from the shoal and channel areas exceed those expected from simple molecular diffusion by factors of 4 and 2, respectively, apparently due to macrofaunal irrigation. Values of the gas transfer coefficient for radon exchange across the air-water interface were determined by constructing a radon mass balance for the water column and by direct measurement using floating chambers. The chamber method appears to yield results which are too high. Transfer coefficients computed using the mass balance method range from 0.4 m/day to 1.8 m/day, with a 6-year average of 1.0 m/day. Gas exchange is linearly dependent upon wind speed over a wind speed range of 3.2–6.4 m/s, but shows no dependence upon current velocity. Gas transfer coefficients predicted from an empirical relationship between gas exchange rates and wind speed observed in lakes and the oceans are within 30% of the coefficients determined from the radon mass balance and are considerably more accurate than coefficients predicted from theoretical gas exchange models.

  16. Inferences drawn from two decades of alinement array measurements of creep on faults in the San Francisco Bay Region

    Science.gov (United States)

    Galehouse, J.S.; Lienkaemper, J.J.

    2003-01-01

    We summarize over 20 years of monitoring surface creep on faults of the San Andreas system in the San Francisco Bay region using alinement arrays. The San Andreas fault is fully locked at five sites northwest from San Juan Bautista, the southern end of the 1906 earthquake rupture, that is, no creep (San Gregorio, Rodgers Creek, and West Napa faults show no creep. The measured creep rate on the Calaveras-Paicines fault from Hollister southward is either 6 or ??? 10 mm/yr, depending on whether the arrays cross all of the creeping traces. Northward of Hollister, the central Calaveras creep rate reaches 14 ?? 2 mm/yr but drops to ??? 2 mm/yr near Calaveras Reservoir, where slip transfers to the southern Hayward fault at a maximum creep rate of 9 mm/yr at its south end. However, the Hayward fault averages only 4.6 mm/yr over most of its length. The Northern Calaveras fault, now creeping at 3-4 mm/yr, steps right to the Concord fault, which has a similar rate, 2.5-3.5 mm/yr, which is slightly slower than the 4.4 mm/yr rate on its northward continuation, the Green Valley fault. The Maacama fault creeps at 4.4 mm/yr near Ukiah and 6.5 mm/yr in Willits. The central and southern segments of the Calaveras fault are predominantly creeping, whereas the Hayward, Northern Calaveras, and Maacama faults are partly locked and, along with the Rodgers Creek and San Andreas, have high potential for major earthquakes.

  17. A Study of the San Andreas Slip Rate on the San Francisco Peninsula, California

    Science.gov (United States)

    Feigelson, L. M.; Prentice, C.; Grove, K.; Caskey, J.; Ritz, J. F.; Leslie, S.

    2008-12-01

    The most recent large earthquake on the San Andreas Fault (SAF) along the San Francisco Peninsula was the great San Francisco earthquake of April 18, 1906, when a Mw= 7.8 event ruptured 435-470 km of the northern SAF. The slip rate for this segment of the SAF is incompletely known but is important for clarifying seismic hazard in this highly urbanized region. A previous study south of our site has found an average slip rate of 17±4 mm/yr for the late Holocene on the San Francisco Peninsula segment of the SAF. North of the Golden Gate, the SAF joins the San Gregorio Fault with an estimated slip rate of 6 mm/yr. A trench study north of where the two faults join has produced an average late Holocene slip rate of 24±3 mm/yr. To refine slip-rate estimates for the peninsula segment of the SAF, we excavated a trench across the fault where we located an abandoned channel between the San Andreas and Lower Crystal Springs reservoirs. This abandoned channel marks the time when a new channel cut across the SAF; the new channel has since been offset in a right-lateral sense about 20 m. The measured amount of offset and the age of the youngest fluvial sediments in the abandoned channel will yield a slip rate for the San Francisco Peninsula segment of the SAF. We excavated a trench across the abandoned channel and logged the exposed sediments. Our investigation revealed channel-fill alluvium incised and filled by probable debris flow sediments, and a wide fault zone in bedrock, west of the channel deposits. The most prominent fault is probably the strand that moved in 1906. We completed a total-station survey to more precisely measure the offset stream, and to confirm that the fault exposed in the trench aligns with a fence that is known to have been offset 2.8m during the 1906 earthquake. We interpret the debris flow sediments to represent the last phase of deposition prior to abandonment of the old channel. We collected samples for radiocarbon dating, optically stimulated

  18. Depth to Transition--Pigeon Point to South Monterey Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the depth-to-transition map of the Pigeon Point to South Monterey Bay, California, region. The raster data file is included in...

  19. Depth to Transition--Pigeon Point to South Monterey Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the depth-to-transition map of the Pigeon Point to South Monterey Bay, California, region. The raster data file is included in...

  20. Don’t Work, Work at Home, or Commute? Discrete Choice Models of the Decision for San Francisco Bay Area Residents

    OpenAIRE

    Ory, D T; Mokhtarian, Patricia L

    2005-01-01

    Using socio-demographic, personality, and attitudinal data from 1,680 residents of the San Francisco Bay Area, we develop and estimate binary, multinomial, and nested logit models of the choice to work or not, whether or not to work at home, and whether to commute all of the time or some of the time (either by only working part time, or by working a compressed work week, or by telecommuting some of the time). To our knowledge, these are the first models of all these choices simultaneously. Th...

  1. Nitrogen deposition and sensitive ecosystems: a case study from the San Francisco Bay Area

    Science.gov (United States)

    Weiss, S. B.

    2001-12-01

    Nitrogen deposition from urban smog can greatly affect local ecosystems. This paper examines a complex situation in the Santa Clara Valley, CA where N-deposition from existing, new, and proposed developments threatens an ecosystem supporting numerous rare, threatened, and endangered species. Grasslands on nutrient-poor serpentinitic soils are being invaded by nutrient-demanding introduced annual grasses, driven by dry N-deposition of about 10 kg ha-1 yr-1. These grass invasions threaten the native biodiversity of the serpentinitic grasslands, including the federally-protected Bay checkerspot butterfly. Additional NOx and NH3 sources planned for the region include a 600 MW natural gas fired power plant, industrial parks that may eventually draw 20,000 to 50,000 additional cars per day, 25,000 housing units, and associated highway improvements. Ongoing mitigation proposals include purchase and long-term management of hundreds of hectares of habitat. The situation is a model for understanding N-deposition from a scientific and policy viewpoint. Fundamental biogeochemical questions include: 1) What are the relative contributions of NOx and NH3 to increased N-deposition? NH3 slip from power plant NOx scrubbers can release more reactive nitrogen than is removed as NOx, and modern automobiles release NH3 in addition to NOx. 2) How are N-emissions transported, chemically modified, and deposited on the local ecosystems, and are these processes adequately captured in regulatory models? How do point sources differ from line sources such as a heavily traveled freeway? 3) What are the effects of chronic N-deposition on the ecosystem, and is there a critical load or a steady cumulative effect? 4) What are the effects of management such as fire, grazing, mowing on N-cycling and plant composition? Policy issues include: 1) What are the incremental impacts of individual projects relative to high background deposition, 2) What margin of safety should be built into modeling and

  2. Process-based, morphodynamic hindcast of decadal deposition patterns in San Pablo Bay, California, 1856-1887

    Science.gov (United States)

    van der Wegen, M.; Jaffe, B.E.; Roelvink, J.A.

    2011-01-01

    This study investigates the possibility of hindcasting-observed decadal-scale morphologic change in San Pablo Bay, a subembayment of the San Francisco Estuary, California, USA, by means of a 3-D numerical model (Delft3D). The hindcast period, 1856-1887, is characterized by upstream hydraulic mining that resulted in a high sediment input to the estuary. The model includes wind waves, salt water and fresh water interactions, and graded sediment transport, among others. Simplified initial conditions and hydrodynamic forcing were necessary because detailed historic descriptions were lacking. Model results show significant skill. The river discharge and sediment concentration have a strong positive influence on deposition volumes. Waves decrease deposition rates and have, together with tidal movement, the greatest effect on sediment distribution within San Pablo Bay. The applied process-based (or reductionist) modeling approach is valuable once reasonable values for model parameters and hydrodynamic forcing are obtained. Sensitivity analysis reveals the dominant forcing of the system and suggests that the model planform plays a dominant role in the morphodynamic development. A detailed physical explanation of the model outcomes is difficult because of the high nonlinearity of the processes. Process formulation refinement, a more detailed description of the forcing, or further model parameter variations may lead to an enhanced model performance, albeit to a limited extent. The approach potentially provides a sound basis for prediction of future developments. Parallel use of highly schematized box models and a process-based approach as described in the present work is probably the most valuable method to assess decadal morphodynamic development. Copyright ?? 2011 by the American Geophysical Union.

  3. Contours--Offshore of Half Moon Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore of Half Moon map area, California. The vector data file is...

  4. Community characteristics associated with HIV risk among injection drug users in the San Francisco Bay Area: a multilevel analysis.

    Science.gov (United States)

    Bluthenthal, Ricky N; Do, D Phuong; Finch, Brian; Martinez, Alexis; Edlin, Brian R; Kral, Alex H

    2007-09-01

    Community characteristics have been associated with racial and ethnic health disparities for a wide range of ailments and conditions. Previous research has found that rates of AIDS cases among injection drug users (IDUs) vary by community characteristics. However, few studies have examined whether community characteristics are associated with HIV risk behaviors among IDUs. To address this gap in the literature, we examined the associations between census-tract-level community characteristics and injection-related and sex-related HIV risk behaviors among IDUs in the San Francisco Bay Area. Individual HIV risk behaviors were collected from 4,956 IDUs between 1998 and 2002. Using 2000 US census data, we constructed four census-level community measures: percent African American, percent male unemployment, percent of households that receive public assistance, and median household income. All community variables were measured continuously. Multilevel modeling was used to determine if community characteristics were associated with recent (in the last 6 months) receptive and distributive syringe sharing, multiple sex partners, and unprotected sex risk while controlling for potential individual-level confounders. In bivariate analysis, most of the census-tract-level community characteristics were significantly associated with injection-related HIV risk, while no community characteristics were associated with sex-related risk. However, results from multivariate multilevel models indicate that only percent African American in a census tract was associated with receptive [adjusted odds ratio (AOR) = 0.93; 95% confidence interval (CI) = 0.89, 0.99] and distributive syringe sharing (AOR = 0.94; 95% CI = 0.92, 0.99), net of individual-level characteristics. Accounting for individual-level factors in the multivariate model in the sex-related risk models revealed a significant inverse relationship between percent African American and propensity to engage in unprotected sex (AOR = 0

  5. Influence of anthropogenic alterations on geomorphic response to climate variations and change in San Francisco Bay-Delta and watershed

    Science.gov (United States)

    Florsheim, J.L.; Dettinger, M.D.

    2004-01-01

    Global warming and attendant sea-level rise may soon impact geomorphic processes in the Sacramento-San Joaquin River and San Francisco Bay Delta systems. During the past two centuries, dramatic anthropogenic changes in sediment supply and pervasive structural controls on rivers and floodplains have altered geomorphic responses to floods throughout a zone that extends upstream from tidally influenced areas to dams that regulate flow. Current geomorphic responses to floods differ from natural responses due to historical actions that concentrated the pre-disturbance multiple-channel and flood-basin system into single channels isolated by levees from increasingly developed floodplains and flood bypass channels, altered flow and sediment regimes, and caused subsidence of leveed Delta Islands. A review of historic and current geomorphic responses to floods illustrates the dominance of structural controls on geomorphic changes in the lowland part of the Sacramento-San Joaquin system. Current climate-change projections for CA suggest that the total volume of snowmelt runoff that may be shifted from spring and added to winter flows is roughly 5 maf/yr, similar to the volume currently available for flood storage in Sierra Nevadan reservoirs. Changes in timing of reservoir releases to accommodate these changes could add to either the magnitude or duration of winter flood peaks, each causing different geomorphic responses. Increased wintertime flows that accompany already large floods could increase overbank flood extent, erosion, and sedimentation, or alternatively increase the depth and strength of confined flows and increase the risk of levee failures. Runoff released from reservoirs as a relatively constant addition to winter baseflow would increase the duration of bankfull or possibly "levee-full" flows. This scenario could lead to bank and levee failure through increased saturation and seepage erosion. Projected sea level rise of 1-2 m would compound vulnerability of

  6. 75 FR 39166 - Safety Zone; San Francisco Giants Baseball Game Promotion, San Francisco, CA

    Science.gov (United States)

    2010-07-08

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; San Francisco Giants Baseball Game... Bay off San Francisco, CA in support of the San Francisco Giants Baseball Game Promotion. This safety... Giants will sponsor the San Francisco Giants Baseball Game Promotion on July 16, 2010, on the...

  7. U.S. EPA honors San Francisco Bay Area firm Hybrid Coating Technologies with Green Chemistry Award

    Science.gov (United States)

    SAN FRANCISCO - Today the U.S. Environmental Protection Agency recognized Hybrid Coating Technologies of Daly City, Calif. with a Presidential Green Chemistry Award for developing a safer, plant-based polyurethane for use on floors, furniture and in

  8. Chronic sublethal effects of San Francisco Bay sediments on nereis (neanthes) arenaceodentata; effect of food ration on sediment toxicity. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Moore, D.W.; Dillon, T.M.

    1993-09-01

    This report is designed to address concerns regarding the effect of food ration on toxicity during chronic sublethal sediment bioassays. To this end, a contaminated San Francisco Bay sediment and a clean control sediment were evaluated in a chronic sublethal test under a series of different food rations, with the marine polychaete worm Nereis (Neanthes) arenaceodentata. Animals were exposed from early juvenile stage through the onset of gametogenesis. Treatments were 2.OX, 1.OX, 0.5X, and 0.25X where X is the recommended food ration for laboratory cultures. Test end points were survival, growth, and reproduction. The contaminated sediment was a composite of several cores taken to project depth (38 ft (11.6 m) below mean low water mark) from an area in Oakland Inner Harbor known to be contaminated with polycyclic aromatic hydrocarbons and metals. Comparisons were made with a clean control sediment. The control sediment is used in the laboratory cultures of N. arenaceodentata and was collected from Sequim, WA. Mean percent survival of Neanthes was high (>90 percent) in both the contaminated and control sediment across all food ration treatments. Individual wet weights were significantly reduced with decreasing food ration in both contaminated and control sediments. Significant differences in wet weight between sediment types were observed at the 1.OX, 0.5X, and 0.25X rations. Reproduction (fecundity and emergent juvenile (EJ) production) was also Chronic sublethal, Neanthes, Dredged material, San Francisco Bay, Food ration, Sediment.

  9. Seismic velocities and geologic logs from boreholes at three downhole arrays in San Francisco, California

    Science.gov (United States)

    Gibbs, James F.; Fumal, Thomas E.; Borcherdt, Roger D.; Warrick, Richard E.; Liu, Hsi-Ping; Westerlund, Robert E.

    1994-01-01

    The Loma Prieta earthquake of October 17, 1989 (1704 PST), has reinforced observations made by Wood and others (1908) after the 1906 San Francisco earthquake, that poor ground conditions (soft soil) increase the likelihood of shaking damage to structures. Since 1908 many studies (for example Borcherdt, 1970, Borcherdt and Gibbs, 1976, Borcherdt and Glassmoyer, 1992) have shown that soft soils amplify seismic waves at frequencies that can be damaging to structures. Damage in the City of San Francisco from the Loma Prieta earthquake was concentrated in the Marina District, the Embarcadero, and the China Basin areas. Each of these areas, to some degree, is underlain by soft soil deposits. These concentrations of damage raise important questions regarding the amplification effects of such deposits at damaging levels of motion. Unfortunately, no strong-motion recordings were obtained in these areas during the Loma Prieta earthquake and only a limited number (< 10) have been obtained on other soft soil sites in the United States. Consequently, important questions exist regarding the response of such deposits during damaging earthquakes, especially questions regarding the nonlinear soil response. Towards developing a data set to address these important questions, borehole strong-motion arrays have been installed at three locations. These arrays consist of groups of wide-dynamic-range pore-pressure transducers and three-component accelerometers, the outputs of which are recorded digitally. The arrays are designed to provide an integrated set of data on ground shaking, liquifaction-induced ground failure, and structural response. This report describes the detailed geologic, seismic, and material-property determinations derived at each of these sites.

  10. "As Good As It Gets": Undocumented Latino Day Laborers Negotiating Discrimination in San Francisco and Berkeley, California, USA.

    Science.gov (United States)

    Quesada, James; Arreola, Sonya; Kral, Alex; Khoury, Sahar; Organista, Kurt C; Worby, Paula

    2014-04-01

    Undocumented Latino day laborers in the United States are vulnerable to being arrested and expelled at any time. This social fact shapes their everyday lives in terms of actions taken and strategies deployed to mitigate being confronted, profiled, and possibly incarcerated and deported. While perceptions of threat and bouts of discrimination are routine among undocumented Latino day laborers, their specific nature vary according to multiple social factors and structural forces that differ significantly from locale to locale. The experience of discrimination is often tacitly negotiated through perceptions, decisions, and actions toward avoiding or moderating its ill effects. This essay examines urban undocumented Latino day laborers over a variety of sites in the greater San Francisco Bay Area, which, compared to many metropolitan areas in the U.S. is "as good as it gets" in terms of being socially tolerated and relatively safe from persecution. Nonetheless, tacit negotiations are necessary to withstand or overcome challenges presented by idiosyncratic and ever changing global, national/state, and local dynamics of discrimination. [undocumented Latino laborers, social exclusion, discrimination, tacit negotiation].

  11. Data from Theodolite Measurements of Creep Rates on San Francisco Bay Region Faults, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The data comprise an archive of repeated surveyed measurements to monitor surface fault creep (a form of gradual tectonic movement) occurring along active faults in...

  12. 2010 U.S. Geological Survey (USGS) Topographic LiDAR: San Francisco Bay, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The primary purpose of this project was to develop a consistent and accurate surface elevation dataset derived from high-accuracy Light Detection and Ranging (LiDAR)...

  13. Hybridization between invasive Spartina Densiflora (Poaceae) and native S. Foliosa in San Francisco Bay, California, USA

    Science.gov (United States)

    Rapid evolution in contemporary time can result when related species, brought together through human-aided introduction, hybridize. The evolutionary consequences of post introduction hybridization range from allopolyploid speciation to extinction of species through genetic amalg...

  14. Three-Dimensional Geologic Map of the Hayward Fault Zone, San Francisco Bay Region, California

    Science.gov (United States)

    Phelps, G.A.; Graymer, R.W.; Jachens, R.C.; Ponce, D.A.; Simpson, R.W.; Wentworth, C.M.

    2008-01-01

    A three-dimensional (3D) geologic map of the Hayward Fault zone was created by integrating the results from geologic mapping, potential field geophysics, and seismology investigations. The map volume is 100 km long, 20 km wide, and extends to a depth of 12 km below sea level. The map volume is oriented northwest and is approximately bisected by the Hayward Fault. The complex geologic structure of the region makes it difficult to trace many geologic units into the subsurface. Therefore, the map units are generalized from 1:24,000-scale geologic maps. Descriptions of geologic units and structures are offered, along with a discussion of the methods used to map them and incorporate them into the 3D geologic map. The map spatial database and associated viewing software are provided. Elements of the map, such as individual fault surfaces, are also provided in a non-proprietary format so that the user can access the map via open-source software. The sheet accompanying this manuscript shows views taken from the 3D geologic map for the user to access. The 3D geologic map is designed as a multi-purpose resource for further geologic investigations and process modeling.

  15. 2013 NOAA Ortho-rectified Color Mean High Water Mosaic of North San Francisco Bay, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  16. Shallow benthic habitats of San Francisco Bay, California CMECS substrate component

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has been developed for the National Oceanic and Atmospheric Administration's (NOAA) Office for Coastal Management (OCM) as a collaborative and...

  17. Shallow benthic habitats of San Francisco Bay, California CMECS biotic component

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has been developed for the National Oceanic and Atmospheric Administration's (NOAA) Office for Coastal Management (OCM) as a collaborative and...

  18. 2010 U.S. Geological Survey (USGS) Topographic LiDAR: San Francisco Bay, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The primary purpose of this project was to develop a consistent and accurate surface elevation dataset derived from high-accuracy Light Detection and Ranging...

  19. Fisherman’s Wharf Area, San Francisco Bay, California Design for Wave Protection.

    Science.gov (United States)

    1985-10-01

    T C) 0 00 0- 00 000 j Zcc;CC 6cC cooc 0) a\\ L3- Cr) c a) 00 A 0.- om LO 00 0 - 3 oc . OLA 0,00 ’.0a 0.a Cflh 𔃺 -0 ’h 𔃺𔃺 0 ’O’’-a .; C ’s0 𔃺h C...0OC0C >- 4 ) N m N A11 C~~A (’n ’ N ’~ r𔃻𔃻 Nm m mnNN y n*C ; C Al’ (V(Y C m mmor N r) 41 V) 03 cW q :1 - o\\0 o3-10 0)) Wv Zy (Y) C)i ~ 0 bOLA

  20. H10727: NOS Hydrographic Survey , San Francisco Bay, California, 1996-12-16

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  1. Shallow benthic habitats of San Francisco Bay, California CMECS geoform component

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has been developed for the National Oceanic and Atmospheric Administration's (NOAA) Office for Coastal Management (OCM) as a collaborative and...

  2. Fecal indicator bacteria and Salmonella in ponds managed as bird habitat, San Francisco Bay, California, USA

    Science.gov (United States)

    Shellenbarger, G.G.; Athearn, N.D.; Takekawa, J.Y.; Boehm, A.B.

    2008-01-01

    Throughout the world, coastal resource managers are encouraging the restoration of previously modified coastal habitats back into wetlands and managed ponds for their ecosystem value. Because many coastal wetlands are adjacent to urban centers and waters used for human recreation, it is important to understand how wildlife can affect water quality. We measured fecal indicator bacteria (FIB) concentrations, presence/absence of Salmonella, bird abundance, and physico-chemical parameters in two coastal, managed ponds and adjacent sloughs for 4 weeks during the summer and winter in 2006. We characterized the microbial water quality in these waters relative to state water-quality standards and examined the relationship between FIB, bird abundance, and physico-chemical parameters. A box model approach was utilized to determine the net source or sink of FIB in the ponds during the study periods. FIB concentrations often exceeded state standards, particularly in the summer, and microbial water quality in the sloughs was generally lower than in ponds during both seasons. Specifically, the inflow of water from the sloughs to the ponds during the summer, more so than waterfowl use, appeared to increase the FIB concentrations in the ponds. The box model results suggested that the ponds served as net wetland sources and sinks for FIB, and high bird abundances in the winter likely contributed to net winter source terms for two of the three FIB in both ponds. Eight serovars of the human pathogen Salmonella were isolated from slough and pond waters, although the source of the pathogen to these wetlands was not identified. Thus, it appeared that factors other than bird abundance were most important in modulating FIB concentrations in these ponds.

  3. 2013 NOAA Ortho-rectified Color Mean High Water Mosaic of South San Francisco Bay California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  4. Interferometric Sidescan Bathymetry, Sediment and Foraminiferal Analyses; a New Look at Tomales Bay, California

    Science.gov (United States)

    Anima, Roberto J.; Chin, John L.; Finlayson, David P.; McGann, Mary; Wong, Florence L.

    2008-01-01

    The United States Geological Survey (USGS) in collaboration with Point Reyes National Sea Shore (PRNS), and the Tomales Bay Watershed Council [http://www.tomalesbaywatershed.org/] has completed a detailed bathymetric survey, and sediment and foraminiferal analyses of the floor of Tomales Bay, California. The study goals are to detail the submarine morphology, the sediment distribution, sedimentary features, and distribution of foraminifera to provide a framework for future studies. The USGS collected swath bathymetric data with a SEA SWATHplus interferometric sidescan sonar system (2004, 2005) and an echo sounder system (2006). The data were processed into continuous mosaic images that show bathymetric detail of the bay floor with 0.2-m vertical and 4.0-m horizontal resolution. Acoustic backscatter data from the 2004 and 2005 surveys were processed into 2-m resolution grids. In addition, 27 sediment samples were collected from various parts of the bay for grain size analyses and a comprehensive study of the distribution of foraminifera in Tomales Bay. The foraminiferal analysis determined that the invasive foraminifera Trochammina hadai from Japan was present in Tomales Bay. The project was conducted in response to a request from the National Park Service, and the Tomales Bay Watershed Council who voiced a need to look at the environmental impacts of human input to the surrounding watersheds that ultimately flow into the bay. The mapping, sediment, and foraminiferal data establish a baseline survey for future comparisons of possible geologic and anthropogenic changes that might occur due to changes in land use or development in the surrounding watershed. These data may also aid in determining the possible pathways of pollutants entering the bay from the surrounding watersheds.

  5. Three-dimensional crustal structure influences on wave propagation and generation of strong ground motion in the greater San Francisco Bay region

    Science.gov (United States)

    Stidham, Christiane Wilson

    Recent development of three-dimensional finite-difference codes allows simulation of earthquakes using realistic three-dimensional earth models. These and other developments have shifted emphasis in seismology from earthquake prediction to estimation of location and magnitude of damage in future earthquakes. The accurate calculation of ground motions for future large earthquakes depends upon detailed knowledge of three-dimensional (3D) geologic structure and the earthquake source process, as well as sufficient computational resources. Knowledge of subsurface geologic structure in the San Francisco Bay Area is quite good relative to many areas, and this knowledge has been incorporated into a 3D velocity model of the Bay Area. With access to a 3D finite-difference code (E3D) developed by Shawn Larsen at Lawrence Livermore National Laboratory and use of super-computing resources at Livermore, we are able to complete calculations for simulations of a number of San Francisco Bay Area earthquakes. These include a small 1993 Rodgers Creek event recorded at Berkeley Seismological Laboratory, the 1989 Loma Prieta event recorded on the U.S. Geological Survey and Calif. Div. of Mines and Geology network of strong motion stations, and a number of small South Bay events (including the 8/12/98 San Juan Bautista EQ) recorded on a temporary USGS/UCB/PASSCAL Santa Clara array. In each of these cases, comparison of synthetic results (synthetic seismograms and plots of maximum horizontal ground velocity) from E3D to recorded data from the event gives an excellent opportunity to both judge the usefulness and the constraints necessary in using finite-difference modeling and the validity of the velocity model as it is now constructed. Results show that 3D finite-difference modeling produces waveforms that are often quite comparable to recorded data, and that fit the data considerably better than synthetics waveforms derived with a 1D velocity model. It is also possible to explore the

  6. Application of an unstructured 3D finite volume numerical model to flows and salinity dynamics in the San Francisco Bay-Delta

    Science.gov (United States)

    Martyr-Koller, R.C.; Kernkamp, H.W.J.; Van Dam, Anne A.; Mick van der Wegen,; Lucas, Lisa; Knowles, N.; Jaffe, B.; Fregoso, T.A.

    2017-01-01

    A linked modeling approach has been undertaken to understand the impacts of climate and infrastructure on aquatic ecology and water quality in the San Francisco Bay-Delta region. The Delft3D Flexible Mesh modeling suite is used in this effort for its 3D hydrodynamics, salinity, temperature and sediment dynamics, phytoplankton and water-quality coupling infrastructure, and linkage to a habitat suitability model. The hydrodynamic model component of the suite is D-Flow FM, a new 3D unstructured finite-volume model based on the Delft3D model. In this paper, D-Flow FM is applied to the San Francisco Bay-Delta to investigate tidal, seasonal and annual dynamics of water levels, river flows and salinity under historical environmental and infrastructural conditions. The model is driven by historical winds, tides, ocean salinity, and river flows, and includes federal, state, and local freshwater withdrawals, and regional gate and barrier operations. The model is calibrated over a 9-month period, and subsequently validated for water levels, flows, and 3D salinity dynamics over a 2 year period.Model performance was quantified using several model assessment metrics and visualized through target diagrams. These metrics indicate that the model accurately estimated water levels, flows, and salinity over wide-ranging tidal and fluvial conditions, and the model can be used to investigate detailed circulation and salinity patterns throughout the Bay-Delta. The hydrodynamics produced through this effort will be used to drive affiliated sediment, phytoplankton, and contaminant hindcast efforts and habitat suitability assessments for fish and bivalves. The modeling framework applied here will serve as a baseline to ultimately shed light on potential ecosystem change over the current century.

  7. Does Wind Discourage Sustainable Transportation Mode Choice? Findings from San Francisco, California, USA

    Directory of Open Access Journals (Sweden)

    Hyungkyoo Kim

    2016-03-01

    Full Text Available This paper explores whether and to what extent wind discourages sustainable transportation mode choice, which includes riding public transportation, bicycling, and walking. A six month-long field study was carried out at four locations in San Francisco, a city that has been promoting sustainable transportation mode choice but that experiences high wind levels. It involved surveying pedestrians and on-site recording of microclimate data using various instruments. The survey adopted a mixed-method approach to collect both quantitative and qualitative data. Statistical analyses using Kruskal Wallis tests and ordinal logistic regression models identified the significant effect of wind speed on San Francisco’s residents in estimating their discouragement for waiting at transit stop without shelter, bicycling, and walking. Qualitative data revealed a deeper understanding of how wind influences their sustainable transportation mode choice. This research argues for the need to adopt climate-based efforts in urban planning and policy and sheds light on the climate resilience of cities

  8. Structure and mechanics of the San Andreas-San Gregorio fault junction, San Francisco, California

    Science.gov (United States)

    Parsons, Tom; Bruns, Terry R.; Sliter, Ray

    2005-01-01

    The right-lateral San Gregorio and San Andreas faults meet west of the Golden Gate near San Francisco. Coincident seismic reflection and refraction profiling across the San Gregorio and San Andreas faults south of their junction shows the crust between them to have formed shallow extensional basins that are dissected by parallel strike-slip faults. We employ a regional finite element model to investigate the long-term consequences of the fault geometry. Over the course of 2-3 m.y. of slip on the San Andreas-San Gregorio fault system, elongated extensional basins are predicted to form between the two faults. An additional consequence of the fault geometry is that the San Andreas fault is expected to have migrated eastward relative to the San Gregorio fault. We thus propose a model of eastward stepping right-lateral fault formation to explain the observed multiple fault strands and depositional basins. The current manifestation of this process might be the observed transfer of slip from the San Andreas fault east to the Golden Gate fault.

  9. Tidal Marsh Vegetation of China Camp, San Pablo Bay, California

    OpenAIRE

    Baye, Peter R.

    2012-01-01

    China Camp (Marin County, California) preserves extensive relict stands of salt marsh vegetation developed on a prehistoric salt marsh platform with a complex sinuous tidal creek network. The low salt marsh along tidal creeks supports extensive native stands of Pacific cordgrass (Spartina foliosa). The outer salt marsh accreted following hydraulic gold mining sedimentation. It consists of a wave-scarped pickleweed-dominated (Sarcocornia pacifica) high salt marsh terrace with a broad fringing ...

  10. Seasonal variation of the upwelling trap in the Todos Santos Bay, Baja California

    Science.gov (United States)

    Calva, M. A.; Perez-Brunius, P.; Lopez, M.; Candela, J.; García, E.

    2013-05-01

    Todos Santos Bay is located on the Pacific coast of Baja California, a region characterized by coastal upwelling throughout the year, being more intense in spring and summer. Aquaculture activities are expanding in the bay, so it is important to understand the processes that modulate the water temperature and stratification, given that these in turn affect biological productivity. This work presents an analysis of the seasonal variation of the temperature of the bay and adjacent regions, with satellite data and CTD casts made in quarterly cruises between 2008-2012. It has been observed that, on average, the surface temperature in the bay is warmer than outside, suggesting that upwelled waters that enter the bay are trapped a sufficiently long time to be heated by solar radiation, hence the name upwelling trap. During upwelling events that drive cold waters to the surface in the regions adjacent to the bay, satellite images show that the surface temperature inside the bay can be 4-5 °C higher than the surrounding area. This thermal front is strongest in summer when solar radiation is greater. We have studied the vertical structure of the lens of warm water with CTD data, which shows that its depth does not exceed 10 m and the temperature is 3 to 4 °C warmer than the water below. Preliminary results on the processes involved in the formation and evolution of the upwelling trap at synoptic to monthly scales will be presented, based on the analysis of sea surface temperature images, winds, and currents in the northwestern entrance of the bay.

  11. F00310: NOS Hydrographic Survey , San Francisco Bay and San Pablo Bay, California, 1987-12-01

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  12. Evaluation of older bay mud sediment from Richmond Harbor, California

    Energy Technology Data Exchange (ETDEWEB)

    Pinza, M.R.; Mayhew, H.L.; Word, J.Q.

    1996-09-01

    The older, bay mud (OBM) unit predates modem man and could act as a barrier to the downward transport of contaminants from the younger bay mud (YBM) because of its hard-packed consistency. However, its chemical and biological nature have not been well characterized. Battelle/Marine Sciences Laboratory (MSL) conducted three independent studies of OBM sediment in January 1993, January 1994, and October 1994. These studies evaluated potential chemical contamination and biological effects of OBM that could occur as a result of dredging and disposal activities. These evaluations were performed by conducting chemical analysis, solid-phase toxicity tests, suspended- particulate-phase (SPP) toxicity tests, and bioaccumulation tests on the OBM sediment. If the sediment chemistry and toxicity results showed no or minimal contamination and toxicological responses, then either the OBM could be left exposed in Richmond Harbor after dredging the YBM without leaving a source of contamination, or if the project depths necessitate, the OBM would be acceptable for disposal at an appropriate disposal site.

  13. Temporal changes in HCV genotype distribution in three different high risk populations in San Francisco, California

    Directory of Open Access Journals (Sweden)

    Evans Jennifer

    2011-08-01

    Full Text Available Abstract Background Hepatitis C virus (HCV genotype (GT has become an important measure in the diagnosis and monitoring of HCV infection treatment. In the United States (U.S. HCV GT 1 is reported as the most common infecting GT among chronically infected patients. In Europe, however, recent studies have suggested that the epidemiology of HCV GTs is changing. Methods We assessed HCV GT distribution in 460 patients from three HCV-infected high risk populations in San Francisco, and examined patterns by birth cohort to assess temporal trends. Multiple logistic regression was used to assess factors independently associated with GT 1 infection compared to other GTs (2, 3, and 4. Results Overall, GT 1 was predominant (72.4%, however younger injection drug users (IDU had a lower proportion of GT 1 infections (54.7% compared to older IDU and HIV-infected patients (80.5% and 76.6%, respectively. Analysis by birth cohort showed increasing proportions of non-GT 1 infections associated with year of birth: birth before 1970 was independently associated with higher adjusted odds of GT 1: AOR 2.03 (95% CI: 1.23, 3.34. African-Americans as compared to whites also had higher adjusted odds of GT 1 infection (AOR: 3.37; 95% CI: 1.89, 5.99. Conclusions Although, HCV GT 1 remains the most prevalent GT, especially among older groups, changes in GT distribution could have significant implications for how HCV might be controlled on a population level and treated on an individual level.

  14. Centro de convenciones George R. Moscone, San francisco/California EE.UU.

    Directory of Open Access Journals (Sweden)

    Hellmuth, George

    1983-04-01

    Full Text Available Not available.El Centro Moscone, que ocupa un solar de 4,6 Ha en las afueras de San Francisco, ofrece un total de 60,400 m2 de superficie para exhibiciones, convenciones y reuniones. El salón principal de exposiciones, que con sus 25.500 m2 de superficie subterránea es actualmente el mayor espacio de exhibición —libre de columnas— del mundo tiene una cubierta sostenida por arcos de 85 m de luz. El edificio se completa con un vestíbulo exterior que conecta el salón de exhibiciones con las salas de reuniones y las demás dependencias del Centro. El original sistema estructural de hormigón, en bóveda de canon, del salón principal se desarrolló para adecuarse a tas exigencias de una construcción subterránea por razones de economía de obra y de mantenimiento. La parte superior del techo de esta sala puede soportar una capa de tierra de hasta 2 m de espesor, proporcionando espacio para un parque en la superficie u otra instalación pública que incluya edificaciones de construcción ligera. Acordes con tas colosales dimensiones de este Centro son las instalaciones, que abarcan desde un completo sistema de protección contra incendios y evacuación de personas hasta los sistemas de climatización, iluminación y electricidad.

  15. Draft Environmental Impact Statement, San Francisco Bay to Stockton, California Project. John F. Baldwin Ship Channel. Phase II. Central San Francisco Bay Segment.

    Science.gov (United States)

    1983-12-01

    the potential for bioaccumulation of any of the contaminants tested. 5. Effects on Special Aquatic Sites. The dredging site is an unvegetated...j TABLE A-4 BALDWIN SHIP CAHNNEL BIOACCUMULATION Tapes japonica Tissue Chemistry - Mercury Mercury Tissue Concentration (mg/kg) Treatment Elapsed Time...cod, sablefish, Pacific hake, C-2 ,,- I I_ -,... , " " ’, .... cabezon, English sole, tiger shark , bat ray, spiny dogfish, Sacramento smelt, Pacific

  16. MEDIA ADVISORY: EPA Administrator joins San Francisco Bay government agencies to celebrate nations largest solar energy partnership

    Science.gov (United States)

    SAN FRANCISCO - On May 13, U.S. EPA Administrator Gina McCarthy will join Alameda County to recognize the largest collaborative in the nation among government agencies to site renewable energy at their facilities. Administrator McCarthy, the federal

  17. Can Vertical Migrations of Dinoflagellates Explain Observed Bioluminescence Patterns During an Upwelling Event in Monterey Bay, California?

    Science.gov (United States)

    2012-01-25

    transect (Figure 1). The REMUS transect began near Santa Cruz in the SA, ran out to the buoy Ml (Figure 1), and then returned back to shore. Inshore...Department, California Polytechnic State University, San Luis Obispo , California, USA. ’Monterey Bay Aquarium Research Institute, Moss Landing, California...University, San Luis Obispo , CA 93407, USA. M. J. Oliver, College of Earth, Ocean and Environment, University of Delaware, 700 Pilottown Rd., Lewes, DE 19958, USA. 10 of 10

  18. The influence of salinity and restoration on wetland soil microbial communities and carbon cycling in the San Francisco Bay-Delta Region

    Science.gov (United States)

    Theroux, S.; Hartman, W.; He, S.; Windham-Myers, L.; Tringe, S. G.

    2014-12-01

    Climate change is predicted to increase the average salinity of the San Francisco Bay-Delta watershed as sea levels rise and alpine snow volume decreases. Wetland soil microbial communities are responsible for cycling greenhouse gases and their response to climate change will heavily influence whether increasing salinity will have a negative or positive effect on the net greenhouse gas budgets of wetlands. To better understand the underlying factors determining the balance of greenhouse gas flux in wetland soils, we targeted the microbial communities along a salinity gradient ranging from freshwater to full seawater in the San Francisco Bay-Delta region. Using DNA and RNA sequencing, coupled with greenhouse gas monitoring, we sampled sixteen sites capturing a range of wetland plant types and restoration states. We determined a suite of soil biogeochemical parameters including moisture, carbon and nutrient contents, pH, sulfate, chloride, and trace metal concentrations. The results of our microbial diversity survey (16S rRNA gene Illumina tag sequencing) showed that salinity and sampling location were the primary drivers of belowground microbial community composition. Freshwater wetland soils, with lower sulfate concentrations, produced more methane than saline sites and we found a parallel increase in the relative abundance of methanogen populations in the high-methane samples. Surprisingly, wetland restoration status did not significantly alter microbial community composition, despite orders of magnitude greater methane flux in restored wetlands compared to reference sites. Deeper metagenomic and metatranscriptomic sequencing in a restored wetland allowed us to further evaluate the roles of methanogen abundance and activity in shaping soil methane production. Our study links belowground microbial communities with their greenhouse gas production, providing a mechanistic microbial framework for assessing climate change feedbacks in wetland soils resulting from sea

  19. Is drinking water a risk factor for endemic cryptosporidiosis? A case-control study in the immunocompetent general population of the San Francisco Bay Area

    Directory of Open Access Journals (Sweden)

    Nadle Joelle

    2003-03-01

    Full Text Available Abstract Background Cryptosporidiosis, caused by Cryptosporidium, is an enteric illness that has received much attention as an infection of immunocompromised persons as well as in community outbreaks (frequently waterborne. There are, however, no studies of the risk factors for sporadic community-acquired cryptosporidiosis in the immunocompetent US population. We undertook a case-control study in the San Francisco Bay Area as part of a national study sponsored by the Centers for Disease Control and Prevention to ascertain the major routes of transmission for endemic cryptosporidiosis, with an emphasis on evaluating risk from drinking water. Methods Cases were recruited from a population-based, active surveillance system and age-matched controls were recruited using sequential random-digit dialing. Cases (n = 26 and controls (n = 62 were interviewed by telephone using a standardized questionnaire that included information about the following exposures: drinking water, recreational water, food items, travel, animal contact, and person-to-person fecal contact, and (for adults sexual practices. Results In multivariate conditional logistic regression analyses no significant association with drinking water was detected. The major risk factor for cryptosporidiosis in the San Francisco Bay Area was travel to another country (matched odds ratio [95% confidence interval]: 24.1 [2.6, 220]. Conclusion The results of this study do not support the hypothesis that drinking water is an independent risk factor for cryptosporidiosis among the immunocompetent population. These findings should be used to design larger studies of endemic cryptosporidiosis to elucidate the precise mechanisms of transmission, whether waterborne or other.

  20. Degradation of tributyltin in San Diego Bay, California, waters

    Energy Technology Data Exchange (ETDEWEB)

    Seligman, P.F.; Valkirs, A.O.; Lee, R.F.

    1986-12-01

    Several experiments were carried out to determine the degradation rate of tributyltin (TBT) in microcosms containing harbor water. Unlabeled or /sup 14/C-labeled tributyltin was added to water samples collected from two stations in San Diego Bay, CA. Degradation rates were determined by calculating the rate of loss of the added parent TBT compound. Calculated half-lives in water collected from a yacht harbor (ambient concentration was 0.5 ..mu..g of TBT/L) were 6 and 7 days for light and dark treatments, respectively. Half-lives from a clean-water site (< 0.03 ..mu..g of TBT/L) were 9 and 19 days for light and dark treatments, respectively. The principal degradation product in all experiments was dibutyltin with lesser amounts of monobutyltin. Complete mineralization, measured by the formation of /sup 14/CO/sub 2/, proceeded slowly with a half-life of 50-75 days. Tributyltin at high concentrations (744 ..mu..g/L) was not degraded in sunlight, indicating that photolysis was not taking place and that biological degradation was the primary degradative process for TBT at low ambient concentrations.