WSP01897 - Laserfiche WebLink

Home Browse Search

. . . ~. ~ v) EFFECTS OF SALI~ITY ON ~ATER USE too hard. softening of the supply in large-scale municipal plants or in individual home units may be required. Scaling of ~ater heaters and corrosion of pipes also accelerate with increased salinity or hardness levels. Water quality in the Upper Basin will generally meet the Public Health Service standards with nonmal levels of treatment--settling. filtration, and disinfection. In some cases only disinfection is required. In con- trast to the Upper Basin. the water supply at mOSt points in the Lower Basin does not meet the Public Health Service recommended limits of 500 mg/l for total dissolved solids. exceeding the maximum acceptable limits at times. Mineralized water supplies vith salinity concentrations in the range of those values observed in the Colorado River, hovever, are commonly accepted in the south~estern United States, with little detriment to the potability of the supply. The use of this mineralized supply imposes an increased treatment COSt as hardness levels are high enough that water softening is desirable in addition to normal treatment. Another means of reducing the problem is by mixing better quality water with the saline ~ater. This solution is limited to those areas having other supplies and is an additional cost. E. Economic Impacts In the United States, the total damages attributable to salinity in the Colorado River system as of 1973 was about $53 million per year. By the year 2000, without control measures, these damages will amount to about $124 million per year. These economic impacts are based on Bureau of Reclamation studies ~hich showed that annual direct and indirect losses amount to about $230,000 per mg/l increase in salinity at Imperial Dam. The estimates of damage do not include affects belo~ 500 mg/l for municipal and industrial water and 750 mg/l for agricultural use. '16