ISSN:
1745-6584
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Energy, Environment Protection, Nuclear Power Engineering
,
Geosciences
Notes:
The Tucson, Arizona, metropolitan area has 450,000 inhabitants and is expected to have nearly 800,000 inhabitants by the year 2000. Tucson is totally dependent on ground water drawn from two basin aquifer systems for its water supplies, as are agricultural, mineral and industrial operations in the area.Municipal, agricultural, mineral and industrial ground-water withdrawals in the two basins amount to some 376,000 acre-feet per year (AFY). Dependable ground-water supplies in the two basins amounts to about 80,000 AFY. Thus, the two aquifer systems are overdrafted by approximately 296,000 AFY, 80 percent of which is by irrigation agriculture.In Arizona, ground water belongs to the owner of the land overlying the aquifer. To ensure adequate ground-water supplies, the City of Tucson has been purchasing and retiring farmlands in one of the basins. However, litigation that reached the Arizona Supreme Court led the Court to rule that the City could pump only 2.4 AFY per acre of farmland retired. The City has retired about 12,000 acres in the basin and in 1978 withdrew some 20,000 AFY of ground water for municipal use.Retiring these farmlands to secure water rights impacts on area economy and creates weed problems for farmers who own land near the retired lands. The City of Tucson budgets about $50,000 annually for weed control.A possible alternative to retiring farmlands and to cultivating crops that require heavy irrigation is cultivating arid-adapted vegetation that has economic potential. Jojoba (Simmondsia chinensis) is a shrub native to the Sonoran Desert that appears to be an economically viable arid-land crop. It needs about 1.5 AFY per acre compared with traditional crops grown in the Southwest that have average needs of 4 AFY or more.The economic value of jojoba is based on the oil extracted from its seeds. It is a unique, unsaturated oil composed of nonglyceride esters consisting almost entirely of straight-chain acids and alcohols. Such oils are difficult to synthesize in commercial quantities, and the only known natural source is the sperm whale, an endangered species.If farmers in the basin cultivated jojoba, water use could be reduced by about 2.5 AFY per acre, from 4 AFY per acre for traditional crops to 1.5 AFY for jojoba. Even if the City of Tucson had to subsidize farmers at a rate of $40 per acre for the 10 years it takes jojoba to produce economically feasible yields, the City would save more than 50 percent of the cost to purchase and retire farmlands and still be able to draw water from the basin for municipal uses.This dual use of water in the basin would permit agriculture to continue its contribution to area economy while the City could continue meeting its water needs by piping water out of the basin into the metropolitan area. However, implementing this plan would require changing Arizona ground-water laws.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1745-6584.1980.tb03368.x
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