The static reservoir storage map shows storage in acre-feet for a selection of operationally significant Reclamation reservoirs and reservoir systems. The static map includes data from 29 reservoirs, with eight individual reservoirs displayed on the map and an additional 21 reservoirs grouped into four reservoir systems displayed on the map, as shown in the table below. Storage data can be shown for yesterday's date and historical dates back to January 1, 1990.

Reservoir storage data used in the map is queried from the Reclamation Information Sharing Environment (RISE), Columbia-Pacific Northwest (CPN) Region Hydromet, and United States Geological Survey (USGS), as shown in the table below. Drought intensity data (displayed on the static map for dates after January 1, 2000) is retrieved as a feature service from Esri. Reservoir characteristics including site name, latitude, longitude, and maximum capacity for each reservoir included in the map were obtained from Reclamation’s records.

Daily reservoir storage values, historical statistics, and storage comparisons are compiled in a CSV file that can be accessed at the link under the static map date selector. The CSV file contains values for all reservoirs and systems shown in the PDF map, plus a number of additional reservoirs that were previously displayed in a different visualization that has been replaced by the Western Water Data Dashboard.

Historical statistics are calculated for the specified day of the year over the period from October 1, 1990 through September 30, 2020. For individual reservoirs shown on the map, the statistics were computed individually. For reservoir systems shown on the map, the daily storage was summed across all reservoirs in the system and statistics were computed on the combined time series.

To retrieve the data for the reservoirs in the visualization that are available in RISE, use the RISE API results endpoint.

The RISE API results endpoint root URL is: https://data.usbr.gov/rise/api/result

Query parameters are available to filter results by location ID, parameter ID, and date.

Example of the URL structure with template parameters:
https://data.usbr.gov/rise/api/result?locationId=<LOCATION_ID>&parameterId=<PARAMETER_ID>&dateTime[before]=<START_DATE>&dateTime[after]=<END_DATE>

Full query example URL:
https://data.usbr.gov/rise/api/result?locationId=1533&parameterId=3&dateTime[before]=2024-05-01&dateTime[after]=2024-01-01