Laserfiche WebLink
<br />, " <br />~ <br />c.., <br /> <br />to improved water quality by diluting the high pollutant loads entering Lake <br />Mead via Las Vegas wash. since July 1981, the municipal dischargers in the <br />Las Vegas area have installed chemical addition, reducing the phosphate load <br />to the wash by 90 percent. Attainment of this phosphate reduction has <br />resulted in the associated reduction of biochemical oxygen demand and <br />suspended solids loading from these municipal sources to the wash and the <br />lake. Monitoring conducted during 1983 indicated a high concentration of <br />chlorophyll-a in the inner Las Vegas Bay despite cutbacks in the phosphorus <br />loading. The virgin River, a tributary to Lake Mead, exhibited poor water <br />quality in terms of bacteria, esthetics, and solids, and very minimal fish <br />life. <br /> <br />.... <br />-l <br /> <br />Phosphorus is of concern, chiefly with respect to present and future <br />domestic use and, secondarily, with respect to recreation and fisheries. <br />Studies have indicated that in-lake concentrations greater than 0.013 mg/L <br />will produce algae concentrations which will have adverse effects on <br />recreation, ~nereas other studies have implied that more phosphorus is <br />necessary for fisheries. In view of this, Nevada adopted and implemented the <br />requirements of no more than a mg/L of phosphorus for all point sources. The <br />major point sources are the three large municipal facilities along the Las <br />Vegas wash. <br /> <br />Salinity, hardness, sulfates, and chlorides are of concern with respect <br />to domestic use of water from Lake Mead. The present levels appear to be <br />accepted by the public, although an economic impact is felt as a result of <br />additional treatment at the point of use and damage to plumbing. Nevada is <br />doing its part in maintaining present levels by applying the salinity control <br />policy of the forum to control the industrial and municipal sources. <br /> <br />Another major concern is the high concentration of ammonia in Las vegas <br />Bay. During 1985-86, un-ionized ammonia was observed to be above the chronic <br />toxicity level. Also, a large blue-green algae bloom occurred in 1986 and had <br />an adverse effect on the beneficial uses of the bay. <br /> <br />f. Cal i fomia <br /> <br />The salinity of the Colorado River is a matter of great concern to <br />California. Southern California receives about 65 percent of its total water <br />supply from the Colorado River, which provides a full water supply to about <br />800,000 irrigated acres and a full or supplemental supply to about 12 million <br />people. Because California is located at the lower end of the Colorado River <br />Basin, the water that it diverts contains all of the dissolved salts that have <br />entered the river upstream. <br /> <br />Colorado River water is used in California to grow many specialized high <br />value crops such as avocados, dates, citrus fruits, grapes, and winter <br />vegetables, as well as basic crops such as cotton, alfalfa, wheat, and sugar <br />beets. Because of its high salinity, Colorado River water requires special <br />management so that crop yields may be maintained and low-salt-tolerant plants <br />will not be damaged or killed. Agricultural areas of California are already <br />suffering significant economic detriments in their utilization of Colorado <br />River water. Those detriments will increase if Colorado River salinity levels <br />are allowed to increase with development of the Colorado River Basin. <br /> <br />III-5 <br /> <br />- <br />