USGS - science for a changing world
View of Folsome Lake from Beals Point during the California drought in 2014

California Drought

The USGS closely monitors the effects of drought through data collection and research, and is studying the most recent California drought in the context of long-term hydrologic, climatic, and environmental changes. These studies support successful planning and science-based decision-making by water managers who must address complex issues and competing interests in times of drought. They also and help decision-makers prepare for climate change and possible future drought.



photo of Folsom Lake with a very low water level during the 2012-2017 California drought

What is Drought?

Water quality degradation, surface and groundwater level declines, land subsidence - all are impacts of drought. Understanding the impacts of drought can help mitigate drought-related issues and prepare for future dry periods.



Drought Comparisons

Because of their duration and severity in terms of both lack of rainfall and runoff, the 1928-34 drought, which lasted 7 years, and the 1987-92 drought, which lasted 6 years, are compared to the 2012-16 drought, which lasted 5 years, to assess similarities and differences.

line chart visualizing monthly runoff data for California for water years 1977 (a dry year), 1983 (a wet year), drought years 2014-2017, and a 30-year average.

line chart visualizing monthly runoff data for California for water years 1977 (a dry year), 1983 (a wet year), drought years 2014-2017, and a 30-year average.

Runoff

Runoff data, reservior data, current streamflow conditions


Surface Water

Careful observation and analysis of the movement and condition of surface water is essential for understanding this resource, especially during times of drought. The California Water Science Center uses a network of more than 500 streamgages to collect real-time data on surface water at locations across the state.


Taken in 2014, this photo shows the dry Tuolumne River under a bridge

photo of a groundwater well with sampling lines

Groundwater

Groundwater provides drinking water for a large portion of the nation's population, supplies business and industries, and is used extensively for irrigation. But what happens to this resource during drought?