Unified Interior Regions
California
The Southwest Region includes California, Nevada, and Arizona. The Regional Office, headquartered in Sacramento, provides Center oversight and support, facilitates internal and external collaborations, and works to further USGS strategic science directions.
States L2 Landing Page Tabs
Simulating Land Subsidence
The California Water Science Center has been involved in multiple studies simulating land subsidence associated with groundwater withdrawal. The simulations can be used to estimate the magnitude, location, and timing of subsidence. They can also be used to evaluate management strategies to mitigate adverse effects from subsidence while also optimizing water availability.
Using Numerical Models to Simulate Subsidence
The California Water Science Center has been involved in multiple studies simulating land subsidence associated with groundwater withdrawal. The simulations can be used to estimate the magnitude, location, and timing of subsidence. They can also be used to evaluate management strategies to mitigate adverse effects from subsidence while also optimizing water availability.
Decomposition of Organic Soils in the Sacramento-San Joaquin Delta
The Sacramento-San Joaquin Delta of California was once a great tidal freshwater marsh. It is blanketed by peat and peaty alluvium deposited where streams originating in the Sierra Nevada, Coast Ranges, and South Cascade Range enter San Francisco Bay. In the late 1800s, levees were built along the stream channels, and the land thus protected from flooding was drained, cleared, and planted ('...
Aquifer Compaction due to Groundwater Pumping
Although land subsidence caused by groundwater pumping has caused many negative effects on human civil works for centuries, especially in the highly developed urban or industrialized areas of Europe, the relation between subsidence and groundwater pumpage was not understood or recognized for a long time. Recognition began in 1928 when pioneer researcher O.E. Meinzer of the U.S. Geological...
Genomic Mechanisms that Underlie Lack of Recovery of Prince William Sound Herring Following the 1990s Collapse
In the decades following the Exxon Valdez Oil Spill (EVOS), it has become increasingly apparent that oil can be toxic at extremely low concentrations to developing fish embryos including herring, where some toxic phenotypes may be apparent during embryogenesis, but some are delayed until later in life. Therefore, acute and lingering oil may act as an insidious selective force within...
Land Subsidence in the San Joaquin Valley
The San Joaquin Valley is one of the most productive agricultural regions in the nation. Beginning around the 1920's, farmers relied upon groundwater for water supply. Over time, overpumping caused groundwater-level declines and associated aquifer-system compaction and land subsidence that resulted in permanent aquifer-system storage loss.
Debris-Flow Forecasts Before Wildfires
Release Date: OCTOBER 15, 2018
USGS scientists have been pursuing a way to assess debris-flow hazards before a fire occurs.
Implementing New Acoustic Monitoring Techniques in the Trinity River
Accurate river-sediment data is fundamental to planning and managing river restoration efforts on the Trinity River, and throughout the world’s waterways. The USGS has developed a “hydrophone” that enables scientists to listen to sediment particles as they move along the riverbed in order to inexpensively and reliably record near-continuous sediment-bedload-transport data. For this study,...
Yucaipa Subbasin Integrated Hydrologic Model
The USGS is developing a hydrologic model of the Yucaipa Subbasin to aid in evaluating and managing the groundwater resources in the area. The study results will provide a greater understanding of the geohydrology of the subbasin, and aid in the development of a groundwater-monitoring plan, as well as in the evaluation of potential hydrologic effects of future groundwater development and...
Microbial Biogeochemistry Laboratory
Microbiologists at the Microbial Biogeochemistry Laboratory develop and apply innovative methods to measure key microbial processes. These methods are used to better understand how major biogeochemical cycles (carbon, nitrogen, sulfur, and iron) interact with and control the speciation and fate of metals like mercury and selenium which can impact the health of humans and other organisms.
Organic Chemistry Research Laboratory — Sacramento, California
About the Laboratory
Chemists and hydrologists at the Organic Chemistry Research Laboratory (OCRL) develop targeted analytical methods for the quantitation of chemicals that can impact the health of organisms and humans. They have developed methods in a wide variety of environmental media; in addition to water and sediment, they also analyze a variety of tissue matrices...
Increasing Soil Organic Carbon to Mitigate Greenhouse Gases and Increase Climate Resiliency for California
Rising air temperatures are projected to continue to drive up urban, agricultural, and rangeland water use, straining both surface and groundwater resources. Scientific studies have shown that managing farms, ranches, and public lands to increase soil carbon can increase soil waterholding capacity and increase hydrologic benefits such as increased baseflows and aquifer recharge, reduced...
CoSMoS (Coastal Storm Modeling System) Central California v3.1 flood-hazard projections: average conditions in San Mateo County
This data contains geographic extents of projected coastal flooding, low-lying vulnerable areas, and maximum/minimum flood potential (flood uncertainty) associated with the sea-level rise (SLR) and storm condition indicated.
The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of kilometers) of storm-ind
CoSMoS (Coastal Storm Modeling System) Central California v3.1 water-level projections: average conditions in San Francisco County
This data contains model-derived total water levels (in meters) for the sea-level rise (SLR) and storm condition indicated.
The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of kilometers) of storm-induced coastal flooding and erosion for both current and future sea-level rise (SLR) scenarios. Projecti
Structure-from-motion point cloud of Mud Creek, Big Sur, California, 2017-03-08
Presented here is a point cloud collected by the U.S. Geological Survey (USGS) using an oblique plane-mounted camera system, covering the area of the Mud Creek landslide on California State Route 1 (SR1), Mud Creek, Big Sur, California. The point cloud is referenced to previously published lidar data and contains RGB information as well as XYZ. Point cloud coordinates are in NAD83
CoSMoS (Coastal Storm Modeling System) Central California v3.1 wave-hazard projections: 20-year storm in San Francisco County
This data contains maximum model-derived significant wave height (in meters) for the sea-level rise (SLR) and storm condition indicated.
The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of kilometers) of storm-induced coastal flooding and erosion for both current and future sea-level rise (SLR) scenar
CoSMoS (Coastal Storm Modeling System) Central California v3.1 water-level projections: average conditions in Santa Barbara County
This data contains model-derived total water levels (in meters) for the sea-level rise (SLR) and storm condition indicated.
The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of kilometers) of storm-induced coastal flooding and erosion for both current and future sea-level rise (SLR) scenarios. Projecti
CoSMoS (Coastal Storm Modeling System) Central California v3.1 ocean-currents projections: 20-year storm in San Luis Obispo County
This data contains maximum model-derived ocean currents (in meters per second) for the sea-level rise (SLR) and storm condition indicated.
The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of kilometers) of storm-induced coastal flooding and erosion for both current and future sea-level rise (SLR) scen
Water quality and ancillary data for assessment of uranium concentrations in groundwater, San Joaquin Valley, CA
High concentrations of uranium were detected in samples from wells used for domestic drinking water supplies in the San Joaquin Valley. Of 163 domestic wells sampled by the California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP) and the National Water Quality Program (NWQP) in 2008-2015, 26 percent had uranium concentrations greater than the U.S....
Depth to Transition--Punta Gorda to Point Arena, California
This part of DS 781 presents data for the depth-to-transition map of the Punta Gorda to Point Arena, California, region. The raster data file is included in the "DepthToTransition_PuntaGordaToPointArena.zip," which is accessible from https://doi.org/10.5066/P9PNNI9H.
As part of the USGS's California State Waters Mapping Project, a 50-m grid...
California Flood Activity Alerts
USGS Project Alert Notices RSS feed includes response summaries of USGS streamgaging network activity during storm events in California. These Notices are produced by USGS Streamgaging Programs nationally and can be found on the USGS Current Floods Website.
Drought & Groundwater in California
Long-term groundwater-level data are fundamental to the resolution of problems dealing with groundwater availability and sustainability. Significant periods of time typically are required to collect water-level data needed to assess the effects of climate variability, to monitor the effects of regional aquifer development, or to obtain data sufficient for analysis of water-level trends.
Runoff Estimates for California
Streams, rivers, lakes and reservoirs are important natural resources for irrigation, public supply, wetlands and wildlife. Excess precipitation that flows into these sources is called runoff, and it's an important drought indicator. The California Water Science Center tracks both monthly and annual runoff.
Mojave River and Morongo Groundwater Basins Data
Interactive map of the Mojave and Morongo groundwater basins. Data layers include sites and data for groundwater levels, water quality, and land subsidence. Groundwater data spans 1992 to the present.
Relation between species assemblages of fishes and water quality in salt ponds and sloughs in South San Francisco Bay
This study was conducted to characterize fishery resources inhabiting salt-evaporation ponds and sloughs in South San Francisco Bay, and to identify key environmental variables that influence distribution of fishes. The ponds, which were originally constructed and operated for commercial production of salt, have undergone preliminary modifications...
Mejia, F.; Saiki, M. K.; Takekawa, John Y.Total selenium and selenium species in irrigation drain inflows to the Salton Sea, California, April and July 2007
This report presents the results for two sampling periods during a 4-year monitoring survey to provide a characterization of selenium concentrations in selected irrigation drains flowing into the Salton Sea, California. Total selenium, selenium species, and total suspended solids were determined in water samples, and total selenium was determined...
May, Thomas W.; Walther, Michael J.; Saiki, Michael K.; Brumbaugh, William G.Preliminary analytical results for ash and burned soils from the October 2007 southern California wildfires
The U.S. Geological Survey (USGS) collected ash and burned soils from about 28 sites in southern California wildfire areas (Harris, Witch, Ammo, Santiago, Canyon and Grass Valley) from Nov. 2 through 9, 2007 (table 1). USGS researchers are applying a wide variety of analytical methods to these samples, with the goal of helping identify...
Plumlee, Geoffrey S.; Martin, Deborah A.; Hoefen, Todd; Kokaly, Raymond F.; Hageman, Philip; Eckberg, Alison; Meeker, Gregory P.; Adams, Monique; Anthony, Michael; Lamothe, Paul J.Data from theodolite measurements of creep rates on San Francisco Bay region faults, California: 1979-2007
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...
McFarland, Forrest S.; Lienkaemper, James J.; Caskey, S. John; Grove, KarenSimulations of potential runout and deposition of the Ferguson rockslide, Merced River Canyon, California
INTRODUCTION An active rockslide in Merced River Canyon was first noticed on April 29, 2006 when a few rocks rolled onto Highway 140 between mileposts 103 and 104, compromising traffic on this highway and signaling the onset of renewed activity of the Ferguson rockslide. State highway 140 is one of the main entrances to Yosemite National Park...
Denlinger, Roger P.Dissolved solids in basin-fill aquifers and streams in the southwestern United States
The U.S. Geological Survey National Water-Quality Assessment Program performed a regional study in the Southwestern United States (Southwest) to describe the status and trends of dissolved solids in basin-fill aquifers and streams and to determine the natural and human factors that affect dissolved solids. Basin-fill aquifers, which include the...
Anning, David W.; Bauch, Nancy J.; Gerner, Steven J.; Flynn, Marilyn E.; Hamlin, Scott N.; Moore, Stephanie J.; Schaefer, Donald H.; Anderholm, Scott K.; Spangler, Lawrence E.Earthquake Rate Model 2.2 of the 2007 Working Group for California Earthquake Probabilities, Appendix D: Magnitude-Area Relationships
Summary To estimate the down-dip coseismic fault dimension, W, the Executive Committee has chosen the Nazareth and Hauksson (2004) method, which uses the 99% depth of background seismicity to assign W. For the predicted earthquake magnitude-fault area scaling used to estimate the maximum magnitude of an earthquake rupture from a fault's length...
Stein, Ross S.Near-Surface Structure and Velocities of the Northeastern Santa Cruz Mountains and the Western Santa Clara Valley, California, From Seismic Imaging
Introduction The Santa Clara Valley (SCV) is located in the southern San Francisco Bay area of California and is bounded by the Santa Cruz Mountains to the southwest, the Diablo Ranges to the northeast, and the San Francisco Bay to the north (Fig. 1). The SCV, which includes the City of San Jose, numerous smaller cities, and much of the high-...
Catchings, R.D.; Gandhok, G.; Goldman, M.R.; Steedman, ClareRiding the storm--landslide danger in the San Francisco Bay Area
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...
Adams, KarenSummary of Survival Data from Juvenile Coho Salmon in the Klamath River, Northern California, 2006
Little is known about the survival of ESA-listed juvenile coho salmon during their seaward migration in the lower Klamath River. In 2006, the Bureau of Reclamation funded a study to estimate the survival of radio-tagged juvenile coho salmon in the Klamath River downstream of Iron Gate Dam. A series of models were evaluated to determine if survival...
Beeman, John W.Genetic diversity of infectious hematopoietic necrosis virus from Feather River and Lake Oroville, California, and virulence of selected isolates for Chinook salmon and rainbow trout
Infectious hematopoietic necrosis virus (IHNV) is a significant pathogen of young salmonid fishes worldwide but particularly within the historical range of the Pacific Northwest and California. In the Sacramento and San Joaquin River drainages of California, IHNV outbreaks in juvenile Chinook salmon Oncorhynchus tshawytscha have been observed...
Bendorf, C.M.; Kelley, G.O.; Yun, S.C.; Kurath, Gael; Andree, K.B.; Hedrick, R.P.Life history and ecological characteristics of the Santa Ana sucker, Catostomus santaanae
This study was conducted to document the life history and ecological characteristics of the Santa Ana sucker, Catostomus santaanae, within its native range in southern California. Electrofishing surveys were conducted at 3-month intervals from December 1998 to December 1999 at one site on the San Gabriel River and two sites on...
Saiki, Michael K.; Martin, Barbara A.; Knowles, Glen W.; Tennant, Patrick W.Cover of The HayWired Earthquake Scenario—We Can Outsmart Disaster
Cover of The HayWired Earthquake Scenario—We Can Outsmart Disaster, USGS Fact Sheet 2018-3016
PubTalk 4/2018 - Coral Reefs
Title: The Role of U.S. Coral Reefs in Coastal Protection - Rigorously valuing flood reduction benefits to inform coastal zone management decisions
- Coral reefs are a first line of coastal defense
- We can account for the physical defense that reefs provide
- We can provide value-based information to guide restoration efforts at management-relevant
Changes in Earth's Gravity Reveal Changes in Groundwater Storage
Did you know that changes in the amount of water in aquifers cause small changes in Earth’s gravitational field? When the amount of groundwater in an aquifer changes, either by recharge or by discharge to surface water or wells, the gravitational acceleration at the land surface also changes. In this photo, USGS Research Hydrologist Jeff Kennedy is making measurements of
...MODIS and VIIRS Observe Snowpack in the Sierra Nevada Mountain Range
The Moderate Resolution Imaging Spectroradiometer (MODIS) sensor is located onboard NASA’s Terra and Aqua satellites. The Visible Infrared Imaging Radiometer Suite (VIIRS) sensor is located onboard the joint NASA/NOAA Suomi National Polar-Orbiting Partnership (S-NPP) and data products created by NASA provide a continuation of the MODIS data heritage. These data are crucial
Cowells Beach Snapshot
Snapshot, or first frame of from a 10-minute video taken on April 19, 2018, in Santa Cruz, California. View is from atop a hotel looking down on Cowells Beach, a popular surf spot. Researchers at the USGS are using these and other video images to improve understanding and computer modeling of beach processes, especially those that change the coast.
...HayWired Scenario - Movie
The HayWired earthquake scenario, led by the U.S. Geological Survey (USGS), anticipates the impacts of a hypothetical magnitude-7.0 earthquake on the Hayward Fault. The fault is along the east side of California’s San Francisco Bay and is among the most active and dangerous in the United States, because it runs through a densely urbanized and interconnected region.
Gas chromatograph-mass spectrometer (GCMS) used for pesticide analysis
Organic Chemistry Research Laboratory — Sacramento, California. Gas chromatograph-mass spectrometer - GCMS
CoSMoS Implementation versions
The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of kilometers) of storm-induced coastal flooding and erosion for both current and future SLR scenarios, as well as long-term shoreline change and cliff retreat. Resulting projections for future climate scenarios (sea-level rise and storms) provide
...Little Holland Tract and Liberty Island sample locations, 2014-2017
Sediment sampling locations in the Sacramento-San Joaquin Delta, California near Little Holland Tract and Liberty Island, 2014 to 2017
Earthquake Alerts: Early and Often? Or Possibly Late?
The choice when issuing earthquake warnings is to: 1) issue alerts for weak shaking and potentially provide long warning times, but risk sending alerts for the many events that do not go on to produce damaging ground shaking, or 2) issue alerts only when ground shaking is expected to be damaging, with the tradeoff that the alert will be sent much later, reducing the
...Nearshore survey of San Ysidro Creek
Two USGS scientists operate personal watercraft equipped with sonar and GPS along the beachfront off San Ysidro Creek, near Fernald Point in Montecito, California. They will use the data collected to create bathymetric (depth) maps. Collecting these data on a seasonal basis over many years provides a detailed picture of how the coastline reacts to changes in waves and
...Fieldwork in the Delta
Shruti Khanna (left, California Department of Fish and Wildlife) and Judy Drexler (USGS California Water Science Center) on the USGS Pacific Coastal and Marine Science Center’s research vessel Parke Snavely during fieldwork in the Sacramento-San Joaquin River Delta.
Recently, U.S. Geological Survey researchers and partners working in California’s Channel Islands National Park discovered mammoth remains in uplifted marine deposits that date to about 80,000 years ago, confirming a long-held but never proven hypothesis that mammoths may have been on the Channel Islands long before the last glacial period 25,000 to 12,000 years ago.
Three new sets of maps detail the offshore bathymetry, habitats, geology and submarine environment of the seafloor off the coast of San Francisco, Drakes Bay, and Tomales Point.

2015 marks the centennial of the May 22, 1915 explosive eruption of Lassen Peak.
Everyone knows that California is “earthquake country,” but it is also “volcano country.” The most recent large volcanic eruption in California was 100 years ago at Lassen Peak, in what is now Lassen Volcanic National Park. California is much different today than it was 100 years ago; in 1915 there were no deaths, no injuries, and minimal economic losses due to the eruption.
The U.S. Geological Survey and Clear Channel Outdoor today announced a partnership to provide the public with critical earthquake safety information during April.
Tens of thousands of people along the U.S. Pacific Northwest coastline may not have enough time to evacuate low-lying areas before tsunami waves arrive, according to a new publication by researchers at the U.S. Geological Survey, University of Colorado Boulder, and California State University, Sacramento.
MENLO PARK, Calif.— Smartphones and other personal electronic devices could, in regions where they are in widespread use, function as early warning systems for large earthquakes according to newly reported research.
MENLO PARK, California — Los teléfonos móviles y otros dispositivos electrónicos personales podrían ayudar en las regiones donde se encuentran en uso generalizado, y pueden funcionar como sistemas de alerta para terremotos mayor según la nueva investigación científica recien publicada.
Golden eagles in the Mojave Desert travel farther, to different areas, and at different times of the year than previously understood, according to research by the U.S. Geological Survey and partners from other federal agencies, academia and the private sector.
The U.S. Geological Survey recently launched the Upper Klamath Basin Collaborative Groundwater Monitoring website to provide information on groundwater conditions in the upper Klamath Basin.

Since February 19, 2015 an ongoing series of small earthquakes has been occurring approximately 5 miles southeast of the summit of Mount Shasta, near the Clear Creek Trailhead on a regional, unnamed fault at about 3-5 miles depth.
Several of the 2,798 new US Topo quadrangles for California now display public trails along with segments of the Pacific Crest National Scenic Trail. Also the new maps now show improved data layers such as public land survey information, map symbol redesign, enhanced railroad information and new road source data.