Page 5

Diminishing suitable sites for surface reservoirs, increasing construction costs, inherent wastes from evaporation, all combine to emphasize the natural advantages of utilizing underground storage capacity for cyclic operation. Utilizable underground storage should be considered as much a natural resource as water. Surface-Water Resources Investigations--Over most of the Pacific Southwest, the network of primary gaging stations on principal streams is reasonably adequate. Ultimately, however, a moderate number of roving, secondary stations will be useful to: (1) discriminate uncommitted supplies that may prove to be developable in the Little Colorado and Bill Williams River Basins and elsewhere at scattered places; and (2) determine magnitude and frequency of ephemeral discharge into numerous desert basins, discharge which is a principal source of ground-water recharge. In each year of an initial 5-year period, 50 secondary stations should be established and, each year thereafter, 50 such stations be relocated to new sites. Water Quality and Waste Management--A reconnaissance estimate of the natural salt loads carried by streams of the region and of the changes in load caused currently by irrigation, by industries, and by municipalities should be made now to assist in assessing future water problems. With more extended investigations by successive sub basins or development areas, recurrent specific determinations of the man-caused changes in the salt loads of streams could be made. This program would entail about 10 primary chemical-quality stations and perhaps 50 roving stations maintained for 5-year intervals at each particular site. A most crucial goal of water management in the region should be to seek out all possible means to improve the quality of return-flow waters. A means particularly adaptable to depreciated waters should be sought, whereby water, if improved even moderately, could be reused without restriction. This would involve intensive research into fundamental water chemistry, including neutron activation of contaminated waters and of base-exchange materials. Such a method would be applicable universally. Water Salvage--Some of the hottest and most arid areas in the United States lie within the Pacific Southwest. The growing season is nearly continuous and the semi-arid climate is favorable to luxuriant growth where water is available. Evaporation and transpiration rates are extreme and probably dissipate as much as 97 percent of the sparse precipitation. If an economic means can be found to salvage these waters, the amount available for beneficial uses might be increased several fold. In the Pacific Southwest, hundreds of thousands of acre-feet of water are annually nonbeneficially consumed by phreatophytes--prolific water-using shrubs and trees. Dense growths of salt cedar, arrowweed, IX-5Epson Perfection 4870 Photo, 400 dpi, 8 bit, 14,137,344 byte