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Show The great benefits to be derived from water ex- change among areas now dependent on Colorado River water, if practical conversion methods are perfected, make this activity one of great potential significance. The fifth possible source of water is from ar- tificial rain-making techniques. To date this pos- sibility has stimulated interest. Investigations by the Army Signal Corps, Office of Naval Research, General Electric Co., universities such as New Mexico School of Mines, and others, have de- veloped methods for rain making, and research is continuing. The United States Weather Bureau has studied some of the present methods but has not viewed the possibility of attaining practical results with, optimism. Possible legal implications are complex and must be considered. However, the potential benefits are great. Research in the field is being encouraged. The lone remaining possibility is reuse of sew- age effluent. Research is under way to determine the factors involved in spreading sewage effluents through porous ground strata to replenish under- ground water storage. This method of reclama- tion has been proposed for use in southern Cali- fornia, whexe depletion of ground water basins has become a serious problem. The chemical, physi- cal, and microbiological changes occurring in both the water and the soil are being studied as the water moves progressively downward, as are the rates at which sewage effluents can percolate through soil. For the Colorado Basin this is thought to be a minor source. Conclusions The full development of the basin will depend on completing large engineering projects to use fully all waters of the basin. More effective consump- tive use within the basin also can increase the supply. Following thiis, the basin will continue to be in short supply because of its arid nature. New techniques to produce new sources of water will be required if much of tkie land is to be irrigated. Three poten- tial sources of water to fulfill this need are other basins, the sea, and artificially induced rain. Although the potential demands of the basin for water are at least several times the present supplies, it seems reasonable to assume that: (1) at least some part of the future demands might be met by an exchange of "basin waters for reclaimed sea water or diverted fresli water from distant sources; and (2) if practicable means for increasing rainfall in the 444 basin can be developed, at least some of the present supplies might be made to serve more acres than at present. Increased investigation of all new sources perfected, make this activity one of great potential the basin. 13. Out-of-Basin Diversions The Problem Balancing of out-of-basin diversions of water and in-basin uses. The Situation By definition (b), article II, of the Colorado River Compact, the term Colorado River Basin means: "all of the drainage area of the Colorado River system and all other territory within the United States of America to which the waters of the Colorado River system shall be beneficially applied." In allocating the use of Colorado River water the compact made no distinction between out-of-basin uses and in-basin uses. Similarly, the 1948 Upper Colorado River Basin Compact made no distinction, the manner of use being left to the determinations of the respective States. Although there would be enough water in the river system to serve all the known potential projects within the basin if no further exportation of water is made, the States are finding it more economical to forego construction of some projects within the natural drainage basin m order to make water avail- able for exportation to adjacent watersheds within the basin States. The support and justification for the amount of water allocated to some States was based on the requirements of out-of-basin diver- sions. The known potential basin projects if constructed would deplete the flow of the Colorado River by more than 6 million acre-feet annually. Possibil- ities also exist for exporting an additional 3 million acre-feet annually to areas outside the natural drain- age basin but within the boundaries of the Colorado River Basin States, as permitted by the Colorado River Compact. If all existing or authorized proj- ects were constructed to the possible extent of their ultimate potentialities, they would increase present depletion by approximately 4 million acre-feet an- nually. With present uses depleting the stream by about 7 million acre-feet, the total depletions would aggregate more than 20 million acre-feet, or about |