U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2005–3065

May 2005

STREAMGAGE

PROGRAM

Printed on recycled paper

USGS California Water Science Center

The U.S. Geological Survey (USGS) California Water 

Science Center streamgage program is part of the 

nationwide program that provides streamflow information for a variety of purposes—from flood and landslide 

forecasting to detecting changes in streamflow caused by 

human activities or climate change. This information is 

critical to resource managers, farmers, fishermen, kayakers, land-use planners, engineers, environmentalists, and 

flood forecasters. The program relies on a network of 

streamgaging stations to accurately and reliably measure 

stream height and flow and to accumulate data over long 

periods for many locations. One such gage is the Happy 

Isles streamgage in Yosemite National Park, which 

has been continuously measuring water flowing in the 

Merced River since 1915. The long-term record for this 

gage is providing scientists the clearest picture yet of the 

effects of long-term climate change. The USGS operates 

nearly 7,000 streamgages nationwide of which more than 

500 gages are operated by the USGS California Water 

Science Center. The gages provide daily streamflow 

records that are accessible to the public.

Water Information Critical to California

The availability of fresh water is 

central to the health of the citizens 

and the environment of the United 

States and to the growth of the 

Nation’s economy. This is especially 

true in California, where water 

resources are in high demand and 

water-resource managers often must 

contend with satisfying conflicting 

water-use needs. Water-resource 

managers face human-induced 

problems, such as long-term groundwater over use and water pollution, and thus must do complex operational planning and meet 

strict water-quality standards. In addition, they must prepare 

for natural disasters, such as floods, landslides, droughts, and 

fires. The effects of these problems will continue to increase as 

California’s population grows. Reliable, accurate, and timely 

information from the USGS streamgage program is crucial to 

State and local water-resource managers and to Federal agencies, such as the U.S. Bureau of Reclamation and the U.S. Army 

Corps of Engineers.

Flood Warning and 

Forecasting

Floods are among the 

most frequent and costly 

natural disasters. Flood 

warnings and river-level 

forecasts are essential 

tools for reducing loss of 

life and property. USGS 

streamgage information 

includes historical and upto-date flow data needed to calibrate National Weather Service 

(NWS) models to assure timely and accurate NWS forecasts.

Landslides and Debris Flow

The USGS also measures 

rainfall and ground-water 

levels. These measurements provide critical 

information for issuing 

timely public warnings 

of landslide and debrisflow hazards. Following 

the southern California wildfires in 

October 2003, USGS scientists and 

technicians rapidly deployed instruments to prepare for the upcoming 

storm season. When the State was 

hit with a “pineapple express,” USGS scientists issued landslide 

advisories to the NWS, the California Office of Emergency Services, and other State and Federal agencies. 

Real-Time Information

USGS streamgaging 

stations equipped with 

real-time telemetry are 

integral components of 

reservoir operations and 

river-forecast and floodwarning systems. One 

of the strengths of the 

USGS streamgage realtime network is the ability to provide, at any time, a snapshot of 

the current hydrologic conditions in California and across the 

country. This real-time information, available on the Internet at 

http://water.usgs.gov/, benefits not only engineers and resource, 

emergency, and disaster managers, but also those who enjoy 

recreational activities such as kayaking and fishing. 
USGS California Water Science Center

For more information contact:

Michael V. Shulters, Director

USGS California Water Science Center

shulters@usgs.gov (916) 278-3026

6000 J Street, Placer Hall

Sacramento, CA 95819

http://ca.water.usgs.gov/

Cooperative Support for the Streamgage Program

The USGS California Water Science Center streamgaging 

network is supported by two programs. The Cooperative Water 

Program funds more than 70 percent of the USGS streamgages 

using funds from nearly 130 State or local agencies. The 

National Streamflow Information Program funds the remainder of the program and supports the on-going modernization 

and improvement of the streamgaging network.

California Water Science Center 

Streamgage Network

The USGS 

California Water 

Science Center 

operates about 500 

streamgages in 

California to provide daily streamflow records accessible to the public. 

These streamgages 

are maintained by 

experienced staff 

from field offices located in Eureka, Redding, Ukiah, 

Carnelian Bay, Sacramento, Hayward, Marina, Santa 

Maria, Apple Valley, San Diego, and Poway. 

For more than 100 years, California has depended on 

the USGS to provide streamflow information. Today 

the USGS California Water Science Center streamgage program, as part of the national program, continues to provide 

information needed to monitor changes in streamflow owing to 

changes in agricultural practices, urbanization, ground-water 

development, and climate change.

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