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Published July 25, 2011
Arizona Reservoir Levels(data through 6/30/11)
Data Source(s): National Water and Climate Center
Combined storage in Lakes Mead and Powell increased by about 4.8 million acre-feet in June. As of July 1, total storage in both lakes was at 57 percent of capacity, which is 4.7 percent more than a year ago (Figure 6). The elevation of Lake Powell is projected to peak near 3,660 feet above sea level by the end of July. The last time Lake Powell’s water elevation was at its current level was in October 2001. Storage in the other reservoirs within Arizona’s borders prevented were decreased by more than 150,000 acre-feet in June. San Carlos Reservoir, located in drought-stricken southeastern Arizona, is at a mere 3 percent of capacity.
In water-related news, per capita rates of water deliveries to customers in Phoenix declined by 30 percent between 1990 and 2008, indicating significant gains in efficient water use (July 13, climatecentral.org). Also, a starter tunnel that ultimately will allow water to be drawn from deeper in Lake Mead is near completion (Las Vegas Review-Journal, July 9). A deeper intake will allow continued delivery of water to the Southern Nevada Water Authority, even if one of the two existing intake tunnels is shut down.
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
- Dan Ferguson, CLIMAS Program Director
- Gregg Garfin, Founding Editor, Institute of the Environment
- Zack Guido, CLIMAS Associate Staff Scientist
- Gigi Owen, CLIMAS Assistant Staff Scientist
- Nancy J. Selover, Arizona State Climatologist
- Jessica Swetish, CLIMAS Publications Assistant
Please direct your Southwest Climate Outlook comments and suggestions to Zack Guido.
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