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<br />w <br />o <br />.... <br /> <br />CHAPTER I. <br /> <br />.'COI'E OF I'HOUI.E'! <br /> <br />.. <br />- <br /> <br />The mcrease of salinity in the Colorado River IS not a <br />new or unique Situation In the history of weHern waler <br />resources. W,ner Quality changes ,n the river wele <br />recognized as early as 1903. Today, the salinity <br />prOblem of the Colorado R,yer is viewed as the <br />lorerunner of similar problems of other western tivers <br />such as the A,o Grande, Arkansas. and Platte which afe <br />all affected In different degrees by Increasing salinllY <br />levels. <br /> <br />In geographical terms, the majestiC Colorado River 15 <br />one of the most diverse river basins in the wor )d. The <br />J ,400.mill'.long li""'r originates ,n the Rocky <br />Mountains and flows lhrough scenic canyons and <br />desert vistJS to accommodate drainage from parts 01 <br />seven weSlern states and Mexico. <br /> <br />In its Journe.... (0 the Gull of California. the river carries <br />a ~allnllV burden of about 10 million lOllS :lflnUulty. <br />About one.half of the Sillt concenlfation arises from <br />natural sources. lhe other half from man's use. <br /> <br />The river water is used and reused several times during <br />Its journey. reducing lhe avallabJe water sUl1ply and <br />increaSing salinity along the wa.... In overall terms, the <br />high sallnit.... levels in the lower fiver reaches adversely <br />affect nearly 10,000,000 people and about a million <br />acres of tertile, Irrigated farml,md. SalinllV <br />concenlfallons are expected to have little adverse <br />Impacl on in stream uses such as recreation, <br />hydroelectric power generation, and fish and wildlife. <br />SeriOus economic impacts, however, are expected in <br />the muniCipal. industrial, and agricultural sectors. <br />Recent studies by the Bureau of Reclamation halle <br />shaWl annual economic losses rangmg from $194.000 <br />to $395,000 per mg/l Increase If) sulin't.... at Imperial <br />Dam, Using all annual economiC loss value of $230,000 <br />~r mg'! increase, the total damages attributable 10 <br />salinity If) the Colorado River sY5!em for 1973 are <br />about 553 million. By the year 2000, using the same <br />criteria, rhese damages to the total regional economy <br />could reach about 5124 million per year if water <br />resource development continues and no salinity <br />reduction measures are instituted. <br /> <br />Salinity levels In the Colorado River now range from <br />less than 50 mg'! al the headwaters to average <br />concentrations of about 850 mg.'1 at Imperial Dam. <br />Projected concentrations of total dissolved solids at <br />Imperial Dam for the vear :?Ooo range from 1,160 mg" <br />to about 1,300 mg/I if no salinity control measures are <br />undertaken. <br /> <br /> <br /> <br />SUMMARY <br /> <br />The salinity problem in the Colorado River has been <br />the object of several pasl studies and investigations, <br />VarIous aspects of the prOblem and contra! measures <br />have been pursued by the Bureau of Rectamation, U,S. <br />Geological Survey. Environmental Protection Agency <br />land Its predecessor age-nciesl. Water Resources <br />Council, Colorado R,ver Board of Caldornia, and <br />sevNal Universities. Studies spanning several years have <br />lraced historic salinity levels and flows. sources of salt <br />loading, and the nature dnd magnitude of damages and <br />potenlial control meaSUles. The largest portion of the <br />mll1eral burden and water supply is found to origll1i1te <br />In the Upper Basin. <br /> <br /> <br />The 1972 EPA Enforcement Conference on the <br />Pollution of InterSlale Walers of the Colorado River <br />inlllaled new efforts to establish <In overall salinity <br />control polley for the river, The !.even basin stale <br />conferees and Federal agency represental,ves <br />concluded thdt such a policy would have as its <br />objective the ma.ntenance of ~alinlty concentrations at <br />or below levels presently found in lhe lower main stem <br />while the UPP\'T BaSin continues !O develop its <br />compJcl.appof!loned waters. <br /> <br />Another relaled malh'! highlighting The nl'ed fer <br />baSinWide salinity controls IS a recently executed <br />dQll~ement wllh MeXICO In an effoft to find a <br />permanent, definitive, and 11lSt solution to the <br />internalional salin;ly problem with Mexico. Under the <br />agreement, waler delivered to MeXICO shall haY!" an <br />average ,mnual salinity of no more lhan 115 mg/I (plus <br />Or minus 30 mgill over the average annual salinity of <br />waters arriving at Imperial Dam. This reqUirement is 10 <br />become effectlYi:' Uf)on the authorization of Feder.!1 <br />funds 10 construCl works necessary to achlelle the <br />Ir'mlted (j,fferenllal in salinity Should the river sallfllty <br />further lncr~ase as forecasted. the sallflity level ot <br />water delivered to MeXICO would increa~e Ifl <br />corresponding amounts. <br /> <br />Another recent Iflst,tutlonal consideratIOn in salinity <br />contlol .s recognized in Public La\', 92.500. The 1972 <br />.'Federal Water Pollution Control Act Amendments" <br />have been interpreted by the EPA 10 require numerical <br />salinilY standards on the Colorado River. Accordingly. <br />the seven basin states have been requested to undertake <br />studies ..nd negotiations to develop such sta:ldards and <br />detailed plans of Implementation. Moreover, the law <br />prOVides that by 1977, the "besl practicable.' water <br />pollution control lechnology shall be applil.'d to carry <br />out proposed control measures on the nver, <br /> <br />5 <br />