Overview

The static reservoir storage map and interactive reservoir storage dashboard both show current 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 below. Storage data can be shown for yesterday's date and historical dates back to January 1, 1990. The interactive dashboard includes data from 54 individual reservoirs, as shown below. Storage data for the current date is shown in the map.

Data Sources

Reservoir storage data used in the maps is queried from Columbia-Pacific Northwest (CPN) Region Hydromet, Missouri Basin-Arkansas-Rio Grande-Texas-Gulf (MB-ART) Region Hydromet, Lower Colorado Basin (LCB) Region Hydrologic Database (HDB), Upper Colorado Basin (UCB) Region HDB, California Data Exchange Center (CDEC), and United States Geological Survey (USGS), as shown 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 maps were obtained from Reclamation’s records.

Historical Statistics and Storage Comparisons

Historical statistics for reservoir storage were calculated for each day of the calendar year over the period from January 1, 1990 through December 31, 2020. Historical statistics include: Maximum, 90th Percentile, 70th Percentile, 50th Percentile, 25th Percentile, 10th Percentile, Minimum, and Average. For individual reservoirs shown on the maps, the statistics were computed individually. For reservoir systems shown on the map, the daily storage was summed across all reservoirs in the system and then statistics were computed on the combined time series.

The average storage statistic for each reservoir or reservoir system is shown in the teacup images on both the interactive dashboard and static map. The teacup images on the interactive dashboard also show the 10th and 90th percentiles. Maximum, 70th percentile, 50th percentile, 25th percentile, and minimum statistics are not shown on either map.

Comparisons of the reservoir storage for the specified date to the historical average, historical 50th percentile (median) and reservoir maximum capacity are calculated using the reservoir storage value on the specified date and the historical statistics and reservoir characteristics as described above. The following daily comparisons are calculated: Percent of Median, Percent of Average, and Percent Full (percent of maximum capacity).