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<br />w <br />CJ1 <br />,..... <br />U~ <br /> <br />- <br /> <br />1985 PROGRAM EVALUATION <br /> <br />Data Tables and Cost Effectiveness Summary <br /> <br />The data tables in Appendix A were developed by SCS and <br />Reclam~tion for use in this evaluation. All costs (October <br />1984) and interest rates (8 3/4 percent) have been adjusted <br />to the "same bases. <br /> <br />The cO$teffectiveness figures are also included near the <br />end of 'each set of numbers and are summarized earlier on <br />table 1. <br /> <br />Base Case Conditions/Tarqet Loads <br /> <br />Histor~cal flow and salinity conditions for the Colorado <br />River at Imperial Dam are depicted on figures 5 and 6, <br />respec~ively. Figure 5 shows that the amount of water that <br />reached Imperial Dam in 1984 was almost 19 million acre- <br />feet. ;Since the 1966 closure of Glen Canyon Dam, with the <br />except~on of 1980, 1983, and 1984, flows at Imperial Dam <br />have f~uctuated within the narrow range of 5 to 6 million <br />acre-f~et, primarily due to the filling of Lake Powell <br />(1963-1980) . <br /> <br />The adqitional water in 1980, 1983, and 1984 had a dramatic <br />dilutiqn effect on the salinity concentrations at Imperial <br />Dam. tigure 6 shows 670 mg/L in 1984, the lowest level <br />since ~igh flows in 1949 and 1952 reduced the salinity level <br />at Imp~rial Dam to 639 and 649 mg/L, respectively. <br /> <br />The 1984 salinity reductions at Imperial Dam were due again <br />to exc~ss flow and are expected to have only a temporary <br />inmpac~ on future salinity projections. Salinity reductions <br />in Lak~ Powell will have an impact on short-term (ten-year) <br />salini~y projections, but will have little impact on long- <br />term p~ojections. <br /> <br />The 19a4 flow and salinity conditions represent the initial, <br />or sta~ting, conditions for future CRSS (Colorado River <br />Simula~ion System) scenarios. Significantly lower TDS at <br />Imperial Dam, full reservoir conditions, and improved salt <br />loadin~ estimates, coupled with lower rate of depletions, <br />have e~sentially slowed the projected TDS increase at <br />Imperioil Dam. <br /> <br />The Ba$e Case condition for the CRSS evaluation assumes that <br />no mor~ funds would be expended on salinity control. <br />Consequently, only the completed salinity control units or <br /> <br />43 <br /> <br /> <br />-i4' <br /> <br />''''4 <br />.(fi' <br /> <br />;; <br />"~ <br /> <br />A <br /> <br />,;'r. <br /> <br />1- <br />; <br /> <br />-x <br />, ~l- <br />, <br />, <br />~4; <br />t <br /> <br />11 <br /> <br />:1 <br />'. V!t <br />-~ <br />1 <br /> <br />,"i <br /> <br />, <br />A <br /> <br />, <br />, <br />~ <br />'"l <br />il' <br />1 <br />I <br />1 <br />] <br />Ii <br />1 <br />-'~ <br />~ <br />! <br />~ <br />.~ <br />\~ <br />1 <br />, <br />" <br />,"} <br /> <br />, '~" " <br /> <br /> <br />.,<" , <br />