Home » October 2011 Southwest Climate Outlook » Arizona Reservoir Levels
Recent Conditions
Published October 24, 2011

Arizona Reservoir Levels

 (data through 9/30/11)
Data Source(s): National Water and Climate Center

Combined storage in Lakes Mead and Powell decreased slightly in September, falling by about 50,000 acre-feet, which is typical for this time of year. The bureau of Reclamation is currently increasing storage in Lake Mead in accordance with the rules developed in the landmark 2007 Interim Guidelines for the Lower Basin Shortages and the Coordinated Operations of Lake Powell and Lake Mead. Storage in other reservoirs within Arizona’s borders decreased by more than 140,000 acre-feet in September (Figure 6). Salt River Basin system reservoirs, which supply the Phoenix metropolitan area, are at a healthy 74 percent of capacity.

In water-related news, Prescott-area government officials are dissatisfied with the ability of a U.S. Geological Survey groundwater flow model to accurately simulate the impact of future population growth scenarios on groundwater systems and flow in the Verde River Basin (Prescott Courier, October 10).

Arizona Reservoir levels as a percent of capacity
Notes:

The map gives a representation of current storage levels for reservoirs in Arizona. Reservoir locations are numbered within the blue circles on the map, corresponding to the reservoirs listed in the table. The cup next to each reservoir shows the current storage level (blue fill) as a percent of total capacity. Note that while the size of each cup varies with the size of the reservoir, these are representational and not to scale. Each cup also represents last year’s storage level (dotted line) and the 1971–2000 reservoir average (red line).

The table details more exactly the current capacity level (listed as a percent of maximum storage). Current and maximum storage levels are given in thousands of acre-feet for each reservoir. One acre-foot is the volume of water sufficient to cover an acre of land to a depth of 1 foot (approximately 325,851 gallons). On average, 1 acre-foot of water is enough to meet the demands of 4 people for a year. The last column of the table list an increase or decrease in storage since last month. A line indicates no change.

These data are based on reservoir reports updated monthly by the National Water and Climate Center of the U.S. Department of Agriculture’s Natural Resource Conservation Service (NRCS). For additional information, contact Dino DeSimone, Dino.DeSimone@az.usda.gov.

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