The State of California is experiencing one of the most severe droughts on record, which has implications for citizens of California and beyond. Many State, Federal, and Tribal agencies make routine observations of and collect data about various componets of the water cycle, but these data may not be easy to visualize. An interactive website developed by the Center for Integrated Data Analytics (CIDA) within the USGS Office of Water Information (http://cida.usgs.gov/ca_drought/) compiles these data and graphically displays them to help viewers understand the effect of drought on California water resources including streamflow amounts, actual reservoir volume compared to peak capacity, drought intensity, land cover change, and water use. The data presented on the website are drawn from free and publicly-accessible sources, and the analytical, graphical, and software tools are open-source and available for public use.
Changes in reservoir volume impact the surface area of reservoirs. Above, Landsat imagery was used to estimate the change in surface area from August 2011 to August 2014 for two of California's largest reservoirs, Shasta Reservoir and Trinity Lake, both located just under 200 miles northwest of Sacramento, California. The outlets of the two reservoirs are located approximately 15 miles apart. These reservoirs provide water for irrigation, hydroelectric power, drinking water, ecosystem management, and flood control.