The following time series plots show the progress of the 2020-2021 California drought as represented in some major reservoirs in terms of their daily storage amounts (overlain on long-term historical storage percentiles), along with the inflows and outflows that explain those storage changes. Also included are corresponding plots for the 2012-2015 drought. All data shown here is from the California Data Exchange Center.

Notice the rapid transition from reservoir storages near their upper historical limits at the beginning of water-yr 2020 to progressive declines that place some of the reservoirs near or at their historical lower limits in spring 2021.


1. Trinity Lake

For comparison to 2012-2015 drought:


2. Shasta Lake

For comparison to 2012-2015 drought:


3. Oroville Lake

For comparison to 2012-2015 drought:


4. Folsom Lake

For comparison to 2012-2015 drought:


5. Lake Tahoe

Note: Lake Tahoe is surrounded by dozens of inflowing catchments, many ungaged, so that–unlike the other reservoirs here–showing an inflow-outflow plot is impractical.


6. Camanche Lake

For comparison to 2012-2015 drought:


7. Don Pedro Lake

For comparison to 2012-2015 drought:


8. Millerton Lake

For comparison to 2012-2015 drought:


9. Pine Flat Lake

For comparison to 2012-2015 drought:


10. Isabella Lake

For comparison to 2012-2015 drought:


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