Due to a lapse in appropriations, the majority of USGS websites may not be up to date and may not reflect current conditions. Websites displaying real-time data, such as Earthquake and Water and information needed for public health and safety will be updated with limited support. Additionally, USGS will not be able to respond to inquiries until appropriations are enacted. For more information, please see www.doi.gov/shutdown
Regions L2 Landing Page Tabs
Hydrologic variability, water chemistry, and phytoplankton biomass in a large flood plain of the Sacramento River, CA, U.S.A.
The Yolo Bypass, a large, managed floodplain that discharges to the headwaters of the San Francisco Estuary, was studied before, during, and after a single, month-long inundation by the Sacramento River in winter and spring 2000. The primary objective was to identify hydrologic conditions and other factors that enhance production of phytoplankton...Schemel, L.E.; Sommer, T.R.; Muller-Solger, A. B.; Harrell, W.C.
Potential exposure of larval and juvenile delta smelt to dissolved pesticides in the Sacramento-San Joaquin Delta, California
The San Francisco Estuary is critical habitat for delta smelt Hypomesus transpacificus, a fish whose abundance has declined greatly since 1983 and is now listed as threatened. In addition, the estuary receives drainage from the Central Valley, an urban and agricultural region with intense and diverse pesticide usage. One possible factor of the...Kuivila, K.M.; Moon, G.E.
Simulated hydrologic responses to climate variations and change in the Merced, Carson, and American River basins, Sierra Nevada, California, 1900-2099
Hydrologic responses of river basins in the Sierra Nevada of California to historical and future climate variations and changes are assessed by simulating daily streamflow and water-balance responses to simulated climate variations over a continuous 200-yr period. The coupled atmosphere-ocean-ice-land Parallel Climate Model provides the simulated...Dettinger, M.D.; Cayan, D.R.; Meyer, M.K.; Jeton, A.
Spatial and temporal variability of suspended-sediment concentrations in a shallow estuarine environment
Shallow subembayments respond differently than deep channels to physical forces acting in estuaries. The U.S. Geological Survey measured suspended-sediment concentrations at five locations in Honker Bay, a shallow subembayment of San Francisco Bay, and the adjacent channel to investigate the spatial and temporal differences between deep and...Ruhl, Catherine A.; Schoellhamer, David H.
Specific conductance and water temperature data for San Francisco Bay, California, for Water Year 2003
This article presents time-series graphs of specific-conductance and water-temperature data collected in San Francisco Bay during water year 2003 (October 1, 2002, through September 30, 2003). Specific-conductance and water-temperature data were recorded at 15-minute intervals at the following US Geological Survey (USGS) locations (Figure 1):...Buchanan, P.A.
Spring onset in the Sierra Nevada: When is snowmelt independent of elevation?
Short-term climate and weather systems can have a strong influence on mountain snowmelt, sometimes overwhelming the effects of elevation and aspect. Although most years exhibit a spring onset that starts first at lowest and moves to highest elevations, in spring 2002, flow in a variety of streams within the Tuolumne and Merced River basins of the...Lundquist, J.D.; Cayan, D.R.; Dettinger, M.D.
Suspended sediment transport where rivers become estuaries: Sacramento – San Joaquin River Delta, water years 1999-2002
No abstract available.Wright, S.A.; Schoellhamer, D.H.
Trends in the sediment yield of the Sacramento River, California, 1957-2001
Human activities within a watershed, such as agriculture, urbanization, and dam building, may affect the sediment yield from the watershed. Because the equilibrium geomorphic form of an estuary is dependent in part on the sediment supply from the watershed, anthropogenic activities within the watershed have the potential to affect estuary...Wright, Scott A.; Schoellhamer, David H.
Water year 2004: Western water managers feel the heat
This spring, a rare combination of exceptionally warm temperatures and near-record lack of precipitation in the western United States caused a rapid change in hydrologic conditions and an unexpectedly early onset of spring conditions. With much of the western U.S. already in its fifth year of drought, an above-average western snowpack on 1 March...Pagano, Thomas; Pasteris, Phil; Dettinger, Michael; Cayan, Daniel; Redmond, Kelly
Winter orographic precipitation ratios in the Sierra Nevada: Large-scale atmospheric circulations and hydrologic consequences
The extent to which winter precipitation is orographically enhanced within the Sierra Nevada of California varies from storm to storm, and season to season, from occasions when precipitation rates at low and high altitudes are almost the same to instances when precipitation rates at middle elevations (considered here) can be as much as 30 times...Dettinger, M.; Redmond, K.; Cayan, D.
Near-field receiving water monitoring of a benthic community near the Palo Alto Water Quality Control Plant in south San Francisco Bay: February 1974 through December 2003
Analyses of the benthic community structure of a mudflat in South San Francisco Bay over a 29-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 biosentinal clam Macoma balthica from the same area. The community has shifted from being dominated by...Shouse, Michelle K.; Parcheso, Francis; Thompson, Janet K.
Summary of Suspended-Sediment Concentration Data, San Francisco Bay, California, Water Year 2001
Suspended-sediment concentration data were collected in San Francisco Bay during water year 2001 (October 1, 2000-September 30, 2001). Optical backscatterance sensors and water samples were used to monitor suspended sediment at two sites in Suisun Bay, three sites in San Pablo Bay, two sites in Central San Francisco Bay, and three sites in South...Buchanan, Paul A.; Ganju, Neil K.
Nine USGS Science Centers are administered by the Pacific Regional office, which is headquartered in Sacramento, California.