Salinity Problems of the Safford Valley: An Interdisciplinary Analysis
AuthorMuller, Anthony B.
AffiliationDepartment of Hydrology and Water Resources, University of Arizona, Tucson
KeywordsHydrology -- Arizona.
Water resources development -- Arizona.
Hydrology -- Southwestern states.
Water resources development -- Southwestern states.
Water pollution sources
Water quality control
Safford Valley (Ariz)
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RightsCopyright ©, where appropriate, is held by the author.
Collection InformationThis article is part of the Hydrology and Water Resources in Arizona and the Southwest collections. Digital access to this material is made possible by the Arizona-Nevada Academy of Science and the University of Arizona Libraries. For more information about items in this collection, contact firstname.lastname@example.org.
PublisherArizona-Nevada Academy of Science
AbstractA change in groundwater quality, averaging approximately +0.13 millimhos electrical conductivity and +35 ppm chloride per year, has been documented between 1940 and 1972 with data from ten long -term sample wells. The decrement in the water quality of the surficial aquifer seems to be attributable to four major mechanisms. An increase in salinity may be expected from leakage of saline water from the artesian aquifer. Such leakage would be stimulated by pumping- caused reduction of confining pressure, and by the puncture of the cap beds by deep wells. Water reaching the aquifer from natural recharge may contribute salts to the system. Such recharging water, if passed through soluble beds, could contribute to the salt. Lateral movement of water through similar deposits may be a contribution, and the concentration and infiltration of agricultural water could also add to aquifer salinity. The economic analysis of the Safford Valley, based on the modeling of a "Representative Farm" analog, indicates that cotton will remain economical to produce on the basis of the projected salinity trends, for a significant time beyond limits of prediction. The analysis indicates that the optimum salt-resistant crops for the area are being cultivated, and, of these, alfalfa will cease to be productive in large areas of the valley by 1990. The entire valley will not produce alfalfa for profit by 2040. The methodologies shown in the paper indicate how pumping influences salinity change and outline salinity control recommendations for the area.
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