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

Filter Total Items: 588
Date published: January 1, 2017

CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 2 flood-hazard depth and duration projections: 20-year storm in Ventura County

Maximum depth of flooding surface (in cm) in the region landward of the present day shoreline that is inundated for the storm condition and sea-level rise (SLR) scenario indicated. Note: Duration datasets may have occasional gaps in open-coast sections.
The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of k

Date published: January 1, 2017

CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 2 flood-hazard projections: 20-year storm in Orange County

Geographic extent of projected coastal flooding, low-lying vulnerable areas, and maxium/minimum flood potential (flood uncertainty) associated with the sea-level rise 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 erosi

Date published: January 1, 2017

CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 2 water-level projections: average conditions in Orange County

Model-derived total water levels (in meters) for the given storm condition and sea-level rise (SLR) scenario.
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. CoSMoS v3.0 for Souther

Date published: January 1, 2017

CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 2 wave-hazard projections: average conditions in Orange County

Model-derived significant wave height (in meters) for the given storm condition and sea-level rise (SLR) scenario.
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. CoSMoS v3.0 for So

Date published: January 1, 2017

Water pressure/depth and turbidity time-series data from CHC13 Marsh and mudflat stations in San Pablo Bay and China Camp Marsh, California

Files contain hydrodynamic and sediment transport data for the location and deployment indicated. Time-series data of water depth, velocity, turbidity, and temperature were collected in San Pablo Bay and China Camp Marsh as part of the San Francisco Bay Marsh Sediment Experiments. Several instruments were deployed in tidal creek, marsh, mudflat, and Bay locations, gathering data on

Date published: January 1, 2017

Water pressure/depth and turbidity time-series data from CHC14 Marsh and mudflat stations in San Pablo Bay and China Camp Marsh, California

Files contain hydrodynamic and sediment transport data for the location and deployment indicated. Time-series data of water depth, velocity, turbidity, and temperature were collected in San Pablo Bay and China Camp Marsh as part of the San Francisco Bay Marsh Sediment Experiments. Several instruments were deployed in tidal creek, marsh, mudflat, and Bay locations, gathering data on

Date published: January 1, 2017

Groundwater-Quality Data in the Tulare Shallow Aquifer Study Unit, 2014-2015: Results from the California GAMA Priority Basin Project

The U.S. Geological Survey collected groundwater samples from 95 domestic wells in Tulare and Kings Counties, California in 2014-2015. The wells were sampled for the Tulare Shallow Aquifer Study Unit of the California State Water Resources Control Board Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Project’s assessment of the quality of groundwater reso

Date published: January 1, 2017

Water pressure/depth, velocity, and turbidity time-series data from CHC16 Tidal creek stations in San Pablo Bay and China Camp Marsh, California

Files contain hydrodynamic and sediment transport data for the location and deployment indicated. Time-series data of water depth, velocity, turbidity, and temperature were collected in San Pablo Bay and China Camp Marsh as part of the San Francisco Bay Marsh Sediment Experiments. Several instruments were deployed in tidal creek, marsh, mudflat, and Bay locations, gathering data on

Date published: January 1, 2017

CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 2 wave-hazard projections: 1-year storm in Ventura County

Model-derived significant wave height (in meters) for the given storm condition and sea-level rise (SLR) scenario.
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. CoSMoS v3.0 for So

Date published: January 1, 2017

CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 2 water-level projections: 20-year storm in Orange County

Model-derived total water levels (in meters) for the given storm condition and sea-level rise (SLR) scenario.
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. CoSMoS v3.0 for Souther

Date published: January 1, 2017

CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 2 flood-hazard projections: average conditions in Orange County

Geographic extent of projected coastal flooding, low-lying vulnerable areas, and maxium/minimum flood potential (flood uncertainty) associated with the sea-level rise 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 erosi

Date published: January 1, 2017

CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 2 wave-hazard projections: 20-year storm in Santa Barbara County

Model-derived significant wave height (in meters) for the given storm condition and sea-level rise (SLR) scenario.
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. CoSMoS v3.0 for So

Filter Total Items: 485
Publication Thumbnail
Year Published: 1975

Geohydrologic Reconnaissance of the Imperial Valley, California

Loeltz, Omar J.; Irelan, Burdge; Robison, J.H.; Olmsted, F.H.
Geohydrologic Reconnaissance of the Imperial Valley, California; 1975; PP; 486-K; USGS NUMBERED SERIES; Water Resources of Lower Colorado River-Salton Sea Area; Loeltz, O. J.; Irelan, Burdge; Robison, J. H.; Olmsted, F. H.

Publication Thumbnail
Year Published: 1973

Geohydrology of the Needles area, Arizona, California, and Nevada

Metzger, D.G.; Loeltz, Omar J.
Geohydrology of the Needles area, Arizona, California, and Nevada; 1973; PP; 486-J; USGS NUMBERED SERIES; Water resources of Lower Colorado River-Salton Sea area; Metzger, D. G.; Loeltz, O. J.

Publication Thumbnail
Year Published: 1973

Geohydrology of the Parker-Blythe-Cibola area, Arizona and California

Metzger, D.G.; Loeltz, Omar J.; Irelan, Burdge
Geohydrology of the Parker-Blythe-Cibola area, Arizona and California; 1973; PP; 486-G; USGS NUMBERED SERIES; Water resources of Lower Colorado River-Salton Sea area; Metzger, D. G.; Loeltz, O. J.; Irelan, Burdge

Publication Thumbnail
Year Published: 1973

Geohydrology of the Yuma area, Arizona and California

Olmsted, F.H.; Loeltz, Omar J.; Irelan, Burdge
Geohydrology of the Yuma area, Arizona and California; 1973; PP; 486-H; USGS NUMBERED SERIES; Water resources of Lower Colorado River-Salton Sea area; Olmsted, F. H.; Loeltz, O. J.; Irelan, Burdge

Publication Thumbnail
Year Published: 1970

Physiographic diagrams of parts of the continental borderlands of California and Alaska: 12 physiographic diagrams: Southern California Borderland; Eastern Murray Fracture Zone and Transverse Ranges; Southern Monterey Bay; Monterey Canyon; Central San

Alpha, Tau Rho
Physiographic diagrams of parts of the continental borderlands of California and Alaska: 12 physiographic diagrams: Southern California Borderland; Eastern Murray Fracture Zone and Transverse Ranges; Southern Monterey Bay; Monterey Canyon; Central San; 1970; OFR; 70-5; Alpha, Tau Rho

Filter Total Items: 1,119
A woman wearing a lab coat stands in front of a machine with 6 cylindrical holders, she is placing a bottle in a cylinder.
March 16, 2017

Centrifuge in the sediment prep lab

We spin down a sample of sediment that's mixed with distilled water in a centrifuge. This separates the sediment from the water at the bottom of the sample bottle, and we pour off most of the water. This process removes dissolved salts.

A person wearing a lab coat and rubber gloves holds clear plastic tube with water running into a cylindrical metal pan.
March 16, 2017

Sieving sediment

Washing a sediment sample through two sieves with distilled water lets us measure the fractions of gravel (bigger than 2 millimeters or -1 phi) and sand (2 millimeters to 63 microns, -1 phi to 4 phi). Smaller sediment passes through the sieves into a standard 1-liter graduated cylinder.

A woman in a lab coat holds a tall plastic cylinder with murky water in it, and a plunger to carefully stir the water.
March 16, 2017

Sediment suspension preparation

After adding a little sodium hexametaphosphate dispersant, we use a plunger to carefully stir the cylinder then let it settle, to ensure good mixing and standardized suspension of the sediment.

A woman in a lab coat holds a tall plastic cylinder with murky water in it, and a sampling device to take a small amount out.
March 16, 2017

Subsampling the suspended sediment sample

Lab technician Angela Tan takes a sample of the sediment suspended in liquid, for analysis in one of several ways.

A woman wearing a lab coat pushes a cart with a tube of sediment through a large metal door.
March 16, 2017

Refrigerated sample storage

We take most cores and samples straight from the loading dock into a large walk-in refrigerator (about 780 square feet), kept at the international core curation standard of 4° C plus or minus 2° C. Each core and sample must be labeled with an identifier and metadata, which follows the material through processing and analysis.

A woman in a lab coat holds a small stack of metal sediment sieves, with an enlarged photo of the sieves to show detail.
March 16, 2017

Sediment sieves

We can use the tried-and-true method of washing samples through finer and finer sieves, then weighing the sediment trapped in each sieve, to determine sediment size fractions.

A woman, wearing a lab coat and protective equipment in a laboratory, holds a core in a device that will split the core in half.
March 16, 2017

Geotek core splitter

In the core lab, the Geotek core splitter cuts sediment cores in half lengthwise using oscillating saws and a wire cutter.

A stack of metal pans sit in a metal frame with a ventilation unit behind it, and a hand flips a switch on the machine.
March 16, 2017

Ro-Tap for dry-sieving coarse sediment

At the USGS Pacific Coastal and Marine Science Center, we have 3 WS Tyler RX-29 Ro-Taps that can dry-sieve coarser samples. This machine automatically rotates and taps the stack of sieves, so that smaller sediment falls through to the next sieve. Weighing the sediment trapped in each sieve gives us sediment size fractions.

A woman wearing a lab coat lifts a long thin sediment core from a shelf.
March 16, 2017

Core racks for storage

In the cold storage room at the USGS Pacific Coastal and Marine Science Center, we store cores on large racks that can hold about 4,500 full sized cores or D-tubes with split cores, up to 1.5 meters long.

A woman wearing a lab coat and rubber gloves holds a plastic dropper over a hole in a machine in a laboratory.
March 16, 2017

Laser diffraction for measuring sediment size fractions

The Beckman Coulter LS 13 320 uses laser diffraction to automatically analyze sediment size fractions between 2 millimeters and 0.35 micron (-1 phi to 11.5 phi).

A woman wearing a lab coat and rubber gloves holds a rotating handle on the wall of a rack that runs on a track.
March 16, 2017

Rolling core storage racks

These track-mounted racks pack together to save space. Cranking a handle moves the aisle between racks for core access.

A woman in a lab coat stands in front of a machine operating a turnstile with a beaker in it.
March 16, 2017

X-ray particle-size analysis of sediment settling rates

The Micromeritics Sedigraph III uses X-rays to automatically analyze settling times for sediment sizes between 300 microns and 0.1 microns (2 phi to 13 phi).

Filter Total Items: 991
USGS science for a changing world logo
July 5, 2011

Scientists detected low concentrations of pharmaceutical compounds in groundwater samples from 2.3 percent of tested aquifers used for drinking water in California.  Pharmaceuticals were detected more frequently in urban areas according to results of a U.S. Geological Survey study published in the journal, Science of the Total Environment.

USGS science for a changing world logo
June 23, 2011

 A new U.S. Geological Survey documentary, Turbid Bay: Sediment in Motion, describes ongoing research into the transport of sediment at the margins of San Francisco Bay. 

USGS science for a changing world logo
May 16, 2011

Marine biologists are gathering in Alaska this week to kick off a three-week expedition studying sea otters, as part of a joint U.S.-Canadian project to investigate the ecological health of the Pacific coastline.

The "Pacific Nearshore Project" is a multinational, multiagency project investigating sea otters as health indicators of coastal waters and marine resources from California nort

USGS science for a changing world logo
May 13, 2011

Fecal indicator bacteria, or FIB, sometimes found in the Malibu Lagoon and the near-shore ocean water in Malibu, California, may not be the result of human waste contamination according to preliminary results of a new U.S. Geological Survey study.

USGS science for a changing world logo
April 27, 2011

High concentrations of naturally occurring elements, including arsenic and boron as well as human-introduced compounds such as nitrate, were found in three aquifers studied in the Sacramento Valley. Scientists determined that concentrations of these substances in untreated water exceed state and federal health standards for drinking water. 

USGS science for a changing world logo
April 25, 2011

Beginning on or about June 8th and lasting approximately one month, an airplane under contract to the U.S. Geological Survey, and in partnership with the Utah Geological Survey, will begin collecting and recording geophysical measurements over parts of northern Utah from Snowville, east to Brigham City, and south to Farmington Bay.  The flights will cover the eastern and southern parts of Box

USGS science for a changing world logo
April 8, 2011

A new report issued by the American Red Cross and the U.S. Geological Survey documents the Chilean response and recovery efforts following the Feb. 2010 magnitude 8.8 earthquake and the lessons that California should learn from this disaster.   

USGS science for a changing world logo
April 6, 2011

On April 8, 2011 officials from the Red Cross, the U.S. Geological Survey, and the City of Los Angeles will hold a press conference at Los Angeles City Hall to announce the findings of a just-released report on the magnitude 8.8 earthquake in Chile in 2010 and the implications for Los Angeles.

USGS science for a changing world logo
March 29, 2011

How birds find their way over great distances during homing and migrational flights is the subject of the U.S. Geological Survey public lecture on Thursday, March 31st. After nearly half a century of intensive research, biologists are still unable to agree on how birds manage to navigate with such uncanny accuracy. 

USGS science for a changing world logo
March 29, 2011

How birds find their way over great distances during homing and migrational flights is the subject of the U.S. Geological Survey public lecture on Thursday, March 31st. After nearly half a century of intensive research, biologists are still unable to agree on how birds manage to navigate with such uncanny accuracy. 

USGS science for a changing world logo
March 29, 2011

Nitrogen and phosphorus concentrations decreased in streams of the Santa Ana Basin during 1975–2004, as improved wastewater treatment was implemented basinwide. Nutrient concentrations in the San Joaquin Basin during the same period increased in association with increased land application of nutrients. In the Sacramento Basin nutrient trends were mostly downward. 

USGS science for a changing world logo
March 25, 2011

U.S. Geological Survey field crews recorded the two highest direct measurements made in the last 70 years at two streamgages on the San Lorenzo River yesterday. Woody debris, including large trees, carried by the turbulent river destroyed two flow meters, but new equipment was shuttled in and the record measurements completed.