Laserfiche WebLink
<br />. <br /> <br />SUMMARY (Continued) <br /> <br />o <br />00 <br />l"'..:J <br />o <br /> <br />It has been assumed for purposes of this study that the average <br />rate of pickup of dissolved solids from new irrigated lands would be in <br />the range of zero to 2 tons per acre (zero to 4.5 t/ha) per year. Where <br />comprehensive studies showed a different rate, the different figure was <br />used. The effect of salt contributed from new lands is thus evaluated <br />by computations of salinity concentrations using these. rates, It was <br />also assumed no additional pickup of dissolved solids would occur for <br />lands already under irrigation. Large industries such as powerplants <br />were considered to have no return of salts or water, and salt load <br />changes due to municipal and minor industries were assumed negligible, <br /> <br />The estimated concentrations in milligrams per liter projected for <br />1980, 1990, and 2000 conditions, without salinity control measures, are <br />as follows: <br /> <br /> 1980 1990 2000 <br /> Zero Two Zero Two Zero Two <br /> TIA TIA TIA TIA TIA TIA <br />Lees Ferry 615 622 684 708 693 719 <br />Hoover Dam 760 768 857 883 879 907 <br />Imperial Dam 877 889 1074 1118 1100 1148 <br /> <br />. <br /> <br />Since the above figures from Table E, Part VII were computed by <br />using average 1941-1976 values, they show only average conditions. <br />Actual conditions will produce years of higher flow, producing better <br />quality water, or years of lower flow producing poorer quality water, <br /> <br />The depletions used in this report are for the projects, both <br />authorized and proposed for authorization together with present develop- <br />ments and other proposals for developments as presently planned. <br /> <br />This report includes discussions of the effect of salinity on water <br />uses and potential salinity control measures, Investigations of the <br />potential for water quality improvement on the Colorado River were <br />ini tiated by the Bureau of Reclamation in FY 1972. A report, "Colorado <br />River Water Quality Improvement Program," dated February 1972, describes <br />potential projects for controlling the salinity of the Colorado River. <br />A second report, "Colorado River Water Quality Improvement Program, <br />Status Report," was published by the Bureau of Reclamation in January <br />1974. This report, with appropriate updating by current investigations <br />is the basis for the discussion of the Colorado River Salinity Control <br />program presented in Part VIII. This evaluation of the program is made <br />in accordance with requirements of the Colorado River Salinity Control <br />Act, Public Lsw 93-320, The Final Environmental Impact Statement for <br />the Colorado River Water Quality Improvement Program was completed in <br />May 1977. The final Environmental Impact Statement for the Paradox <br />Valley Unit was submitted to Washington in November 1978. <br /> <br />. <br /> <br />2 <br />