Water storage in Lake Powell dropped 246,000 acre-feet in September to 64 percent of capacity. The level of Lake Mead declined slightly to about 1,094 feet above sea level, lowering it to within 18 feet of the first stage of water allocation reductions. Water levels in all eight Arizona reservoirs reported below declined during September (Figure 6). San Carlos Reservoir currently holds only 3 percent of its capacity—a level not experienced since 2004. Although storage in the Salt and Verde river basin systems declined in September, they are still well above average.

In water-related news, Mesa, Ariz., has asked 350 homeowners associations and 200 apartment communities to conserve water by limiting or eliminating lawn overseeding, which means sowing seed over existing grass in order to fill in the bare patches (abc15.com, October 3). City officials estimate that voluntary overseeding reductions can save approximately 40 million gallons of water, enough to serve 1,700 homes.

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 Larry Martinez, NRCS, Larry.Martinez@az.usda.gov.

More Information:
The most recent reservoir reports can be accessed at the WCC-NRCS Web site: http://www.wcc.nrcs.usda.gov/wsf/reservoir/resv_rpt.html.