OCR Text |
Show of the water right questions involved and the intra- state character of the problems. Proper attention to the timing of new water projects in accordance with demand also can assist. In attempting to solve these problems by including upstream projects in comprehensive plans, individual justification of each element of the plan should be required. 5. Extent of Conflicts between and Associated with Domestic, Irrigation, Industrial, and Other Water Uses. The Problem The extent to which various water uses conflict with one another. The Situation The high rate of pumping of ground water has lowered the water table in some areas, resulting in increased pumping costs for domestic, irrigation, and industrial ground water supplies. Overpump- ing of ground water for one use results eventually in an inadequate supply for other uses. Overpump- ing problems exist, particularly in the southern San Joaquin Valley, and these especially in the area south of the Kaweah River on the east side, and in western Fresno County on the west side. The water table has dropped in some areas approximately 300 feet in the last 30 years, and continues to drop about 10 feet a year. The use of return irrigation water increases hard- ness and other dissolved mineral matter in the lower portions of the streams of the basin and thereby impairs the quality of water for domestic and industrial use available from these portions of the streams. Placer mining and gold dredging operations have an adverse effect on recreational use of streams in the vicinity of mining operations because of sedi- ment washed into the streams. Rivers affected are the upper and central Yuba and American and the lower Feather, Stanislaus, and Tuolumne. In- creased turbidity reduces recreation values generally and has an especially adverse effect on sport fishing. The city of San Francisco diverts a portion of the flow of the Tuolumne River from within the Yosemite National Park for municipal use and claims a right to 400 million gallons a day. The East Bay Municipal Utility District, including Oak- land, Berkeley, and adjacent cities and communi- ties, diverts water from the Mokelumne River and claims 200 million gallons per day. As these munic- ipalities grow they are likely to need the full amount of their claims. The requirements of the cities and communities within the basin also are increasing and are likely to conflict with such use. Use of the Sacramento River in the vicinity of Sacramento and the San Joaquin River at Stockton for the transportation of untreated or inadequately treated waste affects the quality of the downstream water for almost all other uses. Using coliform organisms as an index of pollution, surveys of these streams have shown excessive sewage organisms over 12 miles below these cities. Unless adequate waste treatment is provided this problem may become critical. Conclusions (1) Ground water resources in the basin should be protected from overdraft by State regulation and by the application of conservation measures. Re- search aimed at water reclamation, reuse, and ground water replenishment should be encouraged. (2) Control of water pollution resulting from the discharge of inadequately treated municipal and industrial wastes, including placer mining debris, should proceed as rapidly as possible. (3) The conflict between irrigation and domestic and industrial water use which results from water quality impairment in the lower streams as a con- sequence of return irrigation water is believed to be of only minor importance. While water quality for domestic and industrial use is made less satisfac- tory, it can be corrected by water treatment. Bene- fits derived from irrigation far exceed any increase in water treatment costs which are made necessary by irrigation usage. 6. Placer Mining Activities in Relation to Water Resources Development The Problem Measures, if any, required to control placer min- ing activities, and extent to which mining interests should participate financially in control works. The Situation The discovery of gold in California was primarily responsible for the early development of the State, and gold mining was a very important activity for many years. Quantities of gold existed in alluvial 125 |