Tuesday, April 21, 2009: 3:10 p.m.
Canyon Suites I/II (Hilton Tucson El Conquistador Golf & Tennis Resort )
Saeid Tadayon
,
USGS, Tucson, AZ
Ground-Water Withdrawal Trends for the Douglas, San Pedro, and Willcox Basins in Southeast Arizona, 1991-2007
Saeid Tadayon
U. S. Geological Survey, Tucson, Arizona
Economic development in Arizona is largely influenced by access to adequate water supplies owing to the State’s predominantly semiarid to arid climate. Water demand is met by pumping ground water from aquifers or by conveying surface water through a system of reservoirs and canals. Current and accurate information on water withdrawals help planners, managers, and the public assess the effectiveness of water management policies, regulations, and conservation activities. The USGS, in cooperation with the Arizona Department of water Resources, has been collecting and estimating water withdrawals for selected categories such as irrigation, municipal, and thermoelectric-power uses in most areas in Arizona.
Ground-water withdrawal data have been collected and estimated in the Douglas, San Pedro, and Willcox, basins to identify trends in irrigation, municipal, and thermoelectric-power uses from 1991-2007. Water withdrawals in the Douglas and San Pedro basins are dominated by agriculture and secondarily by municipal use. In the Willcox Basin, they are dominated by irrigation and secondarily by thermoelectric-power and municipal uses.
Because of the climate and lack of surface water, ground water is used to irrigate nearly all agricultural fields in the Douglas, San Pedro, and Willcox Basins. Historically, irrigation accounted for the largest use of water in these areas. Irrigation withdrawals for 2007 accounted for about 89 percent in the Douglas, 70 percent in the San Pedro, and 95 percent in the Willcox Basins. The amount of water withdrawn for irrigation varies greatly from year to year for these basins, primarily because of differences in the consumptive water requirement for different crops and because of changes in irrigated acreage and irrigation systems. Climatic fluctuations also affect water withdrawals for irrigation, power generation, and municipal uses.
