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Year Published: 2004

Changes in Rice Pesticide Use and Surface Water Concentrations in the Sacramento River Watershed, California

Pesticides applied to rice fields in California are transported into the Sacramento River watershed by the release of rice field water. Despite monitoring and mitigation programs, concentrations of two rice pesticides, molinate and thiobencarb, continue to exceed the surface-water concentration performance goals established by the Central Valley...

Orlando, James L.; Kuivila, Kathryn
Attribution: Pacific
Changes in Rice Pesticide Use and Surface Water Concentrations in the Sacramento River Watershed, California; 2004; SIR; 2004-5097; Orlando, James L.; Kuivila, Kathryn M.

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Year Published: 2004

Summary of Suspended-Sediment Concentration Data, San Francisco Bay, California, Water Year 2002

Suspended-sediment concentration data were collected in San Francisco Bay during water year 2002 (October 1, 2001-September 30, 2002). 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.
Attribution: Pacific
Summary of Suspended-Sediment Concentration Data, San Francisco Bay, California, Water Year 2002; 2004; OFR; 2004-1219; Buchanan, Paul A.; Ganju, Neil K.

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Year Published: 2004

Salt-Pond Box Model (SPOOM) and Its Application to the Napa-Sonoma Salt Ponds, San Francisco Bay, California

A box model to simulate water volume and salinity of a salt pond has been developed by the U.S. Geological Survey to obtain water and salinity budgets. The model, SPOOM, uses the principle of conservation of mass to calculate daily pond volume and salinity and includes a salt crystallization and dissolution algorithm. Model inputs include...

Lionberger, Megan L.; Schoellhamer, David H.; Buchanan, Paul A.; Meyer, Scott
Salt-Pond Box Model (SPOOM) and Its Application to the Napa-Sonoma Salt Ponds, San Francisco Bay, California; 2004; WRI; 2003-4199; Lionberger, Megan L.; Schoellhamer, David H.; Buchanan, Paul A.; Meyer, Scott

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Year Published: 2004

A South San Francisco Bay sediment budget: Wetland restoration and potential effects on phytoplankton blooms

No abstract available.

Shellenbarger, G.G.; Schoellhamer, D.H.; Lionberger, M.A.
Attribution: Pacific

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Year Published: 2004

A walk through the hydroclimate network in Yosemite National Park: River chemistry

Visitors to Yosemite National Park (YNP) are fully aware of the weather, snowmelt, waterfalls (Photo 1), and river discharge and river and lake water temperature. They are not, however, thinking about river chemistry because you can’t see, hear, or feel it. So a river chemistry article in Nature Notes needs a familiar background before we...

Peterson, Dave; Smith, Richard; Hager, Stephen

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Year Published: 2004

Air temperature and snowmelt discharge characteristics, Merced River at Happy Isles, Yosemite National Park, Central Sierra Nevada

No abstract available.

Peterson, D.; Smith, R.; Hager, S.; Cayan, D.; Dettinger, M.
Attribution: Pacific

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Year Published: 2004

Calibration of specific conductance, water-temperature, and turbidity instruments

No abstract available.

Ramil, H. R.; Buchanan, P.A.; Sullivan, B. J.; Brewster, G. D.
Attribution: Pacific

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Year Published: 2004

Changes in snowmelt runoff timing in western North America under a 'business as usual' climate change scenario

Spring snowmelt is the most important contribution of many rivers in western North America. If climate changes, this contribution may change. A shift in the timing of springtime snowmelt towards earlier in the year already is observed during 1948-2000 in many western rivers. Streamflow timing changes for the 1995-2099 period are projected using...

Stewart, I.T.; Cayan, Daniel; Dettinger, Michael D.
Changes in snowmelt runoff timing in western North America under a 'business as usual' climate change scenario; 2004; Article; Journal; Climatic Change; Stewart, I. T.; Cayan, D. R.; Dettinger, M. D.

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Year Published: 2004

Elevational dependence of projected hydrologic changes in the San Francisco Estuary and watershed

California's primary hydrologic system, the San Francisco Estuary and its upstream watershed, is vulnerable to the regional hydrologic consequences of projected global climate change. Previous work has shown that a projected warming would result in a reduction of snowpack storage leading to higher winter and lower spring-summer streamflows and...

Knowles, N.; Cayan, D.R.
Elevational dependence of projected hydrologic changes in the San Francisco Estuary and watershed; 2004; Article; Journal; Climatic Change; Knowles, N.; Cayan, D. R.

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Year Published: 2004

Floodtide pulses after low tides in shallow subembayments adjacent to deep channels

In shallow waters surface gravity waves (tides) propagate with a speed proportional to the square root of water depth (c=g(h+η)). As the ratio of free surface displacement to mean depth (η/h) approaches unity the wave will travel noticeably faster at high tide than at low tide, creating asymmetries in the tidal form. This physical process is...

Warner, J.C.; Schoellhamer, D.H.; Ruhl, C.A.; Burau, J.R.
Floodtide pulses after low tides in shallow subembayments adjacent to deep channels; 2004; Article; Journal; Estuarine, Coastal and Shelf Science; Warner, J. C.; Schoellhamer, D. H.; Ruhl, C. A.; Burau, J. R.

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Year Published: 2004

Food web pathway determines how selenium affects aquatic ecosystems: A San francisco Bay case study

Chemical contaminants disrupt ecosystems, but specific effects may be under-appreciated when poorly known processes such as uptake mechanisms, uptake via diet, food preferences, and food web dynamics are influential. Here we show that a combination of food web structure and the physiology of trace element accumulation explain why some species in...

Stewart, A.R.; Luoma, S.N.; Schlekat, C.E.; Doblin, M.A.; Hieb, K.A.
Food web pathway determines how selenium affects aquatic ecosystems: A San francisco Bay case study; 2004; Article; Journal; Environmental Science and Technology; Stewart, A. R.; Luoma, S. N.; Schlekat, C. E.; Doblin, M. A.; Hieb, K. A.

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Year Published: 2004

Hydrologic scales, cloud variability, remote sensing, and models: Implications for forecasting snowmelt and streamflow

Accurate prediction of available water supply from snowmelt is needed if the myriad of human, environmental, agricultural, and industrial demands for water are to be satisfied, especially given legislatively imposed conditions on its allocation. Robust retrievals of hydrologic basin model variables (e.g., insolation or areal extent of snow cover)...

Simpson, James J.; Dettinger, M.D.; Gehrke, F.; McIntire, T.J.; Hufford, Gary L.
Hydrologic scales, cloud variability, remote sensing, and models: Implications for forecasting snowmelt and streamflow; 2004; Article; Journal; Weather and Forecasting; Simpson, J. J.; Dettinger, M. D.; Gehrke, F.; McIntire, T. J.; Hufford, G. L.

Filter Total Items: 223
Tim Elfers watches the incoming waves while conducting a bathymetric survey of the nearshore in Santa Cruz, California.
December 31, 2014

Conducting Bathymetric Surveys

USGS scientist Tim Elfers conducts a bathymetric (depth) survey from a personal watercraft with onboard GPS and echo sounder equipment, in Santa Cruz, California.

USGS ATV is equipped with GPS and collects topographic (elevation) data on Seacliff Beach, Aptos, CA
December 31, 2014

USGS ATV Collecting Topographic Data

Photograph shows a USGS ATV equipped with GPS, ready to collect topographic data on Seacliff Beach in Aptos, California. The pier leads out to the heavily eroded cement ship SS Palo Alto. Various sources reveal that SS Palo Alto was built as an oil tanker by the San Francisco Shipbuilding Company in Oakland, California, and was launched May 29, 1919. She

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USGS geologist standing near an active lava flow with smoke coming from the lava
October 26, 2014

Hawaiʻi Hot Lava

After slowly moving downslope from Kīlauea Volcano’s East Rift Zone since June 27, 2014, this active lava flow in Hawaiʻi reached the town of Pāhoa just before Halloween, destroying roads, a cemetery, and private property in this community. Amazingly, the Pu‘u ‘Ō‘ō vent began erupting in 1983 and has continued erupting essentially nonstop for more than 31

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USGS all-terrain vehicle is equipped with GPS and collects beach topography on Rio Del Mar State Beach, Aptos, CA
October 21, 2014

USGS ATV Collecting Topographic Data

Photograph shows a USGS scientist navigating an all-terrain vehicle equipped with GPS, collecting topographic data on Rio Del Mar State Beach in Aptos, California. Gathering this type of information helps USGS scientists to document the changes in beach and nearshore morphology (or form and structure), caused by seasonal variations and storms.

lone road lined by palm trees on a small flat island, with water from the sea washing over the road
March 31, 2014

Wave-driven flooding and overwash on Roi-Namur Atoll

Wave-driven flooding and overwash on Roi-Namur Atoll, Republic of the Marshall Islands

coastal road and palm trees on a small flat island, with water waves from the sea washing over the road
March 31, 2014

Wave-driven flooding and overwash on Roi-Namur Atoll

Wave-driven flooding and overwash on Roi-Namur Atoll, Republic of the Marshall Islands

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January 2, 2014

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Attribution: Pacific
August 31, 2013

Busy Day in the Sed Lab

Time lapse video of Angela Tan working in a USGS sediment analysis laboratory. More at https://walrus.wr.usgs.gov/labs/coresedlab.html

two men wearing hard hats carrying a 4-foot long auger in a grassy field
August 17, 2013

USGS scientists carrying an auger to a drill hole for seismic survey

USGS scientists Robert Sickler (left) and Rufus Catchings (right) carrying an auger to a drill hole for seismic survey.

two men wearing hard hats attaching a section of an auger to a drill
August 17, 2013

USGS scientists attach an auger to drill for seismic survey

USGS scientists Robert Sickler (below) and Rufus Catchings (standing) attaching a section of an auger bit in order to drill a hole for a seismic survey.

Mount Hood with Portland, Oregon in the foreground.
May 23, 2012

Mount Hood dominates the skyline outside of Portland, Oregon

A major eruption of Mount Hood would pose a great hazard to the regional economy.

Overhead view of coast with green land on right, blue water plus bands of white on left. Sand bars and other features labeled.
April 18, 2012

Ebb-tidal delta at Raglan Bar on New Zealand’s North Island

Seafloor features of the ebb-tidal delta at Raglan Bar on New Zealand’s North Island, as revealed in a composite “time-averaged” image made by averaging light intensities recorded at each pixel in each frame of two videos. The originally oblique image has been transformed into a map view (looking straight down from overhead). CMLB, channel margin linear bar (

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Nine USGS Science Centers are administered by the Pacific Regional office, which is headquartered in Sacramento, California.

The Pacific Region works with a wide array of partners across the country, including other Federal and state agencies, regional and local governments, academic institutions, research organizations, non-governmental organizations, and more.

Filter Total Items: 76