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Published June 20, 2011
Arizona Reservoir Levels(through 5/30/11)
Data Source(s): National Water and Climate Center
Combined storage in Lakes Mead and Powell increased by 1.3 million acre-feet (maf) during May. As of June 1, the lakes’ combined storage was at 50.3 percent of capacity (Figure 6), which is approximately the same as one year ago. Inflow into Lake Powell for May was 2.35 maf, or 102 percent of average, according to the U.S. Bureau of Reclamation. The forecasted unregulated inflow to Lake Powell for June is 6.1 maf, which would be the second highest inflow total for June since the operation of Glen Canyon Dam began in 1963. Lake Powell elevation is predicted to peak in early August at around 35 to 40 feet below the full pool elevation of 3,700 feet. October 2001 was the last time Lake Powell neared this elevation.
Storage in reservoirs not on the Colorado River decreased by 163,600 acre-feet in May, including substantial decreases in storage in the Verde and Salt river basins and in the San Carlos Reservoir.
In water-related news, the U.S. Supreme Court declined to consider an appeal in a 26-year battle over who holds title to the Lower Salt River (Cronkite News, June 13). For the time being the state, rather than private landowners, is considered the titleholder.
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.
Portions of the information provided in this figure can be accessed at the NRCS website:
Southwest Climate Outlook Staff
- Michael Crimmins, UA Extension Specialist
- Stephanie Doster, Institute of the Environment Editor
- Gregg Garfin, Founding Editor, Institute of the Environment
- Zack Guido, Managing Editor, CLIMAS Associate Staff Scientist
- Nancy J. Selover, Arizona State Climatologist
- Jessica Dollin, CLIMAS Publications Assistant
- Dave Dubious, New Mexico State Climatologist
Please direct your Southwest Climate Outlook comments and suggestions to Zack Guido.
The CLIMAS Web site contains official and non-official forecasts, as well as other information. While we make every effort to verify this information, please understand that we do not warrant the accuracy of any of these materials.... Read full disclaimer