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<br />
<br />Table 4
<br />
<br />PROJECTED CONCENTRATIONS OF TOTAL
<br />DISSOLVED SOLIDS (mg/II AT IMPERIAL DAM
<br />(Average annual values)
<br />
<br /> Year
<br />Source 1980 2000 2010 2020 2030
<br />EPA 1,060 1,220
<br />CRBC 1,070 1,340 1,390
<br />WRC 1,260 1,290 1,350
<br />USBR 930 1,160
<br />EPA: Environmental Protection Agency, 1972
<br />CRBC: Colorado River Board of California, 1970
<br />WRC: Water Resources Council (Lower Colorado
<br /> Region Comprehensive
<br /> Framework Studyl, 1971
<br />USBR: Bureau of Reclamation, 1973
<br />
<br />salinity water were used. Municipal and industrial users
<br />are faced with considerable expense due to water
<br />quality. Allowing the salinity of the river to increase
<br />will result in additional economic impacts.
<br />
<br />ECONOMIC IMPACTS
<br />
<br />Economic detriments can be computed using the
<br />projected increases in salinity, under the assumption
<br />that a control program will not be installed. The
<br />adverse effects would be expressed primarily in the
<br />agricultural, municipal, and industrial uses. Few
<br />adverse impacts on instream uses such as recreation,
<br />hydroelectric power generation, and propagation of
<br />aquatic life are expected. The detriments in agriculture
<br />would arise from one or a combination of the
<br />following: decreased crop yields, increased leaching
<br />requirements, increased management costs, and
<br />application of various adaptive practices such as
<br />changes in crop patterns, improved drainage systems,
<br />and plantings on sloping beds. In the municipal and
<br />industrial uses, the detriments arise primarily from
<br />increased water treatment costs, accelerated pipe
<br />corrosion and appliance wear, increased use of soap
<br />and detergents, and decreased palatability of drinking
<br />water.
<br />
<br />Based on the foregoing kinds of impacts, the totai and
<br />direct damages now being experienced and those
<br />contemplated if no salinity control measures are
<br />installed have been determined and the findings are
<br />presented in Table 5. These figures are the relevant
<br />damages, i.e., those caused by salinity levels in excess
<br />of threshold values. The threshold values assumed for
<br />
<br />M&I and agriculture are 500 and 750
<br />respectively.
<br />
<br />Table 5
<br />
<br />TOTAL AND DIRECT DAMAGES
<br />ATTRIBUTABLE TO SALINITY ,
<br />IN THE COLORADO RIVER SYSTEM
<br />
<br />Year Total Direct
<br />1973 $ 53,000,000 $ 49,000,000
<br />1980 72,000,000 64,000,000
<br />1990 111,000,000 96,000,000
<br />2000 124,000,000 107,000,000
<br />2010 147,000,000 126,000,000
<br />
<br />The total damages reflect the impact on the en ire
<br />regional economy whiie the direct damages affect nly
<br />the water users. Damages to water users in Mexico nd
<br />recreation and fishing uses in the Salton Sea have not
<br />been estimated. I
<br />
<br />Applying present worth factors at 6.7/8 percent to the
<br />values from Table 5 indicates the economic magnit de
<br />of the salinity probiem on the Coiorado River. he
<br />present value of the future damages amounts to abput
<br />$1.1 billion for the direct damages and $1.24 bili1ion
<br />for the total damages.
<br />
<br />
<br />PREVIOUS STUDIES AND FINDINGSI
<br />
<br />The salinity problem in the Coiorado River has ien
<br />the object of many studies and investigati ns,
<br />stemming from the deep concern of the states as
<br />expressed during hearings and negotiations ~ith
<br />Mexico relating to the 1944 Mexican Water Tre~ty.
<br />California in particular wanted the water quality i~sue
<br />clearly stated to avoid future misunderstanding. 'Ihis
<br />was not accomplished as recent events have shown. J
<br />
<br />The most relevant studies on salinity in the Color do
<br />River were made by the U.S. Geoiogical Sur ley,
<br />Bureau of Reclamation, Environmental Protection
<br />Agency land its predecessor agenciesl, Water ReSOUlces
<br />Council, Coiorado River Board of California, and U ah
<br />State University..
<br />
<br />The USGS studies concentrate on definition of I he
<br />saiinity probiem. They trace historic salinity iev Is,
<br />estimate salt loading from specific sources, and iden ify
<br />salt contribution from various river reaches. he
<br />Bureau of Reclamation studies report on the pst,
<br />present modified, and future water quality conditi ns
<br />in the basin. The effects of salinity on water uses nd
<br />
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