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<br />w <br />o <br />CO <br />Q) <br /> <br />Environmental Protection Agency (EPA) <br /> <br />Salt Routin~ Studies - EPA suggests that the report <br />include a discuss on of the results of the routing studies <br />developed for the draft report and the basis for the selec- <br />tion of the specific results presented in the report. <br /> <br />The Forum believes the report essentially describes <br />the scenarios examined by the Work Group in conducting the <br />salt routing studies. For clarification, the following <br />changes are to be made on pages 16 and 17. Starting with <br />the third paragraph on page 16, the report should read as <br />follows: <br /> <br />"Historical flow-weighted annual salinities and <br />projected salinities at Imperial Dam for the 14 maf <br />water supply condition and low level of development <br />are shown on Figure 2. The projection for the low <br />level of development and the 14 maf water supply is <br />shown as it approximates the average recent historical <br />rate of development and the average water supply for <br />the period 1941 to 1976. The five-year moving mean <br />of historical and projected salinities is shown on <br />Figure 3. The moving mean dampens annual fluctuations <br />and should be a better indication of salinity trends. <br />These two figures have been included in order to <br />compare historical and projected salinity trends. <br />Figure 4, showing historical and projected salinities <br />at Imperial Dam for the 14 maf water supply condition <br />and moderate level of development, has also been in- <br />cluded to demonstrate the effect of a higher depletion <br />+evel. The approximate effects of a 500 thousand ton <br />per year reduction in base salt load on 1990 salinities <br />are shown on Figures 2 and J+." <br /> <br />Tempora~ Salinity Increases - EPA proposes that a <br />"mitigation s inity control policy" should be maintained. <br />The policy would require that any development project which <br />increased salinity must be accompanied by a decrease in <br />salinity in some other part of the basin, which would at <br />least equal the expected increase. EPA contends this policy <br />is based on the conclusions and recommendations of the Seventh <br />Session of the Conference in the Matter of Pollution of the <br />Interstate Waters of the Colorado River and Its Tributaries <br />and the federal regulations printed in the Federal Register <br />on December 18, 1974. <br /> <br />The basic thrust of the Conference was a basin-wide <br />approach to both salinity control and water development. It <br />did not include the concept that specific water development <br />projects be accompanyed by specific salinity control projects. <br />The l"orum recognizes that the 'duration and magnitude of tempo- <br />rary increases is a potential problem. The present program <br /> <br />4 <br />