Publications
For more than a century, USGS scientists have conducted research in California’s Bay-Delta region. Informing natural-resource management decisions on the region’s issues, this research has been published in thousands of documents, some highlighted below.
Filter Total Items: 307
Mercury bioaccumulation and risk to three waterbird foraging guilds is influenced by foraging ecology and breeding stage Mercury bioaccumulation and risk to three waterbird foraging guilds is influenced by foraging ecology and breeding stage
We evaluated mercury (Hg) in five waterbird species representing three foraging guilds in San Francisco Bay, CA. Fish-eating birds (Forster's and Caspian terns) had the highest Hg concentrations in thier tissues, but concentrations in an invertebrate-foraging shorebird (black-necked stilt) were also elevated. Foraging habitat was important for Hg exposure as illustrated by within-guild...
Authors
Collin A. Eagles-Smith, Joshua T. Ackerman, S.E.W. de la Cruz, John Y. Takekawa
Dietary flexibility in three representative waterbirds across salinity and depth gradients in salt ponds of San Francisco Bay Dietary flexibility in three representative waterbirds across salinity and depth gradients in salt ponds of San Francisco Bay
Salt evaporation ponds have existed in San Francisco Bay, California, for more than a century. In the past decade, most of the salt ponds have been retired from production and purchased for resource conservation with a focus on tidal marsh restoration. However, large numbers of waterbirds are found in salt ponds, especially during migration and wintering periods. The value of these...
Authors
John Y. Takekawa, A.K. Miles, D. C. Tsao-Melcer, D. H. Schoellhamer, S. Fregien, N.D. Athearn
A Viscoelastic earthquake simulator with application to the San Francisco Bay region A Viscoelastic earthquake simulator with application to the San Francisco Bay region
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...
Authors
Fred F. Pollitz
Potential effects of mercury on threatened California black rails Potential effects of mercury on threatened California black rails
San Francisco Bay (SFB) estuary sediments contain high levels of mercury (Hg), and tidal marsh resident species may be vulnerable to Hg contamination. We examined Hg concentrations in California black rails, a threatened waterbird species that inhabits SFB tidal salt marshes. We captured 127 black rails during the prebreeding and postbreeding seasons and examined the influence of site...
Authors
Danika C. Tsao, A. Keith Miles, John Y. Takekawa, Isa Woo
How humans and nature have shaped the San Francisco Estuary since the Gold Rush How humans and nature have shaped the San Francisco Estuary since the Gold Rush
The San Francisco Estuary has undergone dramatic changes since the Gold Rush, as both natural forces and human activities have added and removed massive quantities of sediment, primarily sand and mud. A long-term perspective of sediment movement and patterns of sediment deposition and erosion is vital for effective management of wetlands, sediment contamination, dredging, mining, and...
Authors
B. E. Jaffe
Linking human impacts within an estuary to ebb-tidal delta evolution Linking human impacts within an estuary to ebb-tidal delta evolution
San Francisco Bay, California, USA is among the most anthropogenically altered estuaries in the entire United States, but the impact on sediment transport to the coastal ocean has not been quantified. Analysis of four historic bathymetric surveys has revealed large changes to the morphology of the San Francisco Bar, an ebb-tidal delta at the mouth of the San Francisco Bay. From 1873 to...
Authors
Kate L. Dallas, Patrick L. Barnard
Geomorphic controls on mercury accumulation in soils from a historically mined watershed, Central California Coast Range, USA Geomorphic controls on mercury accumulation in soils from a historically mined watershed, Central California Coast Range, USA
Historic Hg mining in the Cache Creek watershed in the Central California Coast Range has contributed to the downstream transport of Hg to the San Francisco Bay-Delta. Different aspects of Hg mobilization in soils, including pedogenesis, fluvial redistribution of sediment, volatilization and eolian transport were considered. The greatest soil concentrations (>30 mg Hg kg-1) in Cache...
Authors
J.M. Holloway, M. B. Goldhaber, J.M. Morrison
Calibration of an estuarine sediment transport model to sediment fluxes as an intermediate step for simulation of geomorphic evolution Calibration of an estuarine sediment transport model to sediment fluxes as an intermediate step for simulation of geomorphic evolution
Modeling geomorphic evolution in estuaries is necessary to model the fate of legacy contaminants in the bed sediment and the effect of climate change, watershed alterations, sea level rise, construction projects, and restoration efforts. Coupled hydrodynamic and sediment transport models used for this purpose typically are calibrated to water level, currents, and/or suspended-sediment
Authors
N. K. Ganju, D. H. Schoellhamer
Managing water to protect fish: A review of California's environmental water account, 2001-2005 Managing water to protect fish: A review of California's environmental water account, 2001-2005
The Sacramento-San Joaquin Delta, the landward reach of the San Francisco Estuary, provides habitat for threatened delta smelt, endangered winter-run Chinook salmon, and other species of concern. It is also the location of huge freshwater diversion facilities that entrain large numbers of fish. Reducing the entrainment of listed fishes into these facilities has required curtailment of...
Authors
L. R. Brown, W. Kimmerer, R. Brown
Data from theodolite measurements of creep rates on San Francisco Bay region faults, California Data from theodolite measurements of creep rates on San Francisco Bay region faults, California
Introduction 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...
Authors
Forrest S. McFarland, James J. Lienkaemper, S. John Caskey
Mercury concentrations and loads in a large river system tributary to San Francisco Bay, California, USA Mercury concentrations and loads in a large river system tributary to San Francisco Bay, California, USA
In order to estimate total mercury (HgT) loads entering San Francisco Bay, USA, via the Sacramento-San Joaquin River system, unfiltered water samples were collected between January 2002 and January 2006 during high flow events and analyzed for HgT. Unfiltered HgT concentrations ranged from 3.2 to 75 ng/L and showed a strong correlation (r2 = 0.8, p 0.001, n = 78) to suspended sediment
Authors
N. David, L.J. McKee, F.J. Black, A.R. Flegal, C.H. Conaway, D. H. Schoellhamer, N. K. Ganju
Sediment deposition, erosion, and bathymetric change in central San Francisco Bay: 1855-1979 Sediment deposition, erosion, and bathymetric change in central San Francisco Bay: 1855-1979
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...
Authors
Theresa A. Fregoso, Amy C. Foxgrover, Bruce E. Jaffe