California Drought Information
DROUGHT SCIENCE SPOTLIGHT
- Visit our Surface Water page for a graphical historical comparison of stream flows at several selected streamgage sites affected by the drought.
- USGS crews from the California Water Science Center are monitoring conditions on a continuing basis. Many of the nearly 500 stream gages are currently at "below normal" or "much-below normal" flows for this time of year. Learn more...
2013 was the driest calendar year for California in 119 years of recorded history. As of February 21, 2014, the California Department of Water Resources measured the statewide water content of snowpack at only 25% of the average for this time of year. This is 20% of the crucial April 1 measurement, which is when the snowpack is normally at its peak and begins to melt into streams and reservoirs. Snowpack provides about one-third of the water used by California's cities and farms.
Definition of Drought
A drought is a period of drier-than-normal conditions that results in water-related problems. The term "drought" can have different meanings to different people, depending on how a water deficiency affects them. Droughts have been classified into different types such as:
- Meteorological drought - lack of precipitation
- Agricultural drought - lack of soil moisture, or
- Hydrologic drought -reduced streamflow or groundwater levels
USGS Water Science Research Contributes to Decision Making
Drought Conditions Based on Current vs. Historical Streamflow Data
During severe drought, communities and water managers must often make difficult decisions about how scarce water resources will be used. For example, will water be held in reservoirs for the future, or released to satisfy immediate water needs; or, will groundwater pumping be increased to augment surface water supplies.
USGS science provides accurate, trusted, hydrologic data and scientific analysis to help decision makers who must address complex issues and competing interests in times of drought. USGS California Water Science Center scientists work with California communities through the Cooperative Water Program to help:
- Ensure that water is available for many competing uses and users (for example, individual residents, municipalities, hydropower production, navigation, agriculture, recreation, and industry)
- Manage pumping of groundwater that normally flows to streams and is needed to maintain habitat for aquatic and riparian species (on average, greater than 50 percent of streamflow is contributed by groundwater)
- Sustain high water quality for safe drinking and healthy ecosystems
- Plan for reduced snowpack (winter snowpack accounts for between 60 to 80 percent of the annual water supply to more than 70 million people living in the western U.S.)