Laserfiche WebLink
<br />significant irlcrei!~;inq co~:;ts as salinity levels <br />surpass 500 rn~J/1 ,tfl(; Inaxinwm recommended <br />in the U.S. fllvirolllTl(~ntal PI'otectiofl Agoncy <br />SecondcHY Orinki!ll) Water Stnndards.) <br /> <br />l'0 <br />en <br />Ul <br />~, <br /> <br />Alternatives suqgcsted for salinity control in the <br />Coloracio Rive! B,"lSlfl include (1) augmentation <br />of the basin wej(" supply. (2) roduction of salt <br />loads by strLlctu!al n18aSlJres as well as <br />mallClgemGflt (-llteffliitives, (Jnd (3) curtailment of <br />future water resour-ce duvelopment. The <br />featlibility and de~;il()bility of th8se threo salinity <br />contr"ol alterl1(ltive~; Clr(~ influenced by the <br />economics of such actions; e.g" the relative <br />justif-icfltioll ir-olTl (-1 beflnfit versus cost <br />viewpoint. the') rn(;ognitioll of water rights, and <br />the political alld irlstiWtional forces surrounding <br />each alternative. <br /> <br />11 is therefor() I1Ur:CSSiHY from the national <br />economic officianc;y viewpoint to estimate, as <br />accurately as pos:;ible, the economic impacts of <br />ch~'lnges in si-llir1!ty !cv(ds upon users of the <br />waters of the (:olnr<ldo. <br /> <br />Thl) economic vallie of tl1e reduction in salinity <br />lovels rcslJltirlSj from mitigation measures is <br />necessary to jud~Je tho rlesirability of such <br />measures. Sirnil;-lrlyc the negAtivE) economic <br />value of increases in salinity r()sultin~l from the <br />salt IOClrlillg cffoct of retlJrn flows of water <br />development fHOj()cts is r18cessry to judge the <br />desirability of ;,IJc:i1 dev810pment plans. <br /> <br />Ii is recognized dEli morr1 than economic <br />impActs result irolll chanqillg salinity, such as <br />fish and wildlifo, IOf:IQ(ltiofl, and onvironmental <br />impacts. While (ecCl~Jrli/illg that marlY other <br />effects of salillity do exist the ovorriding <br />eOllcer-n addmss8d hme d(:als with the monetary <br />(~ffeets upon di! cet USU! s of Colorado River <br />water. Potentinl diHlli:lUeS ()I" tot31 pc-malty costs <br />from adverse s{Jlitlity conditions can be defined <br />3S the sum of dir [--;ct rOrlcllty costs incurred by <br />w3ter LJsers cHlcl indilccl penalty costs imposed <br />on the economy of the I-egio!l. <br /> <br />Pursuallt to SHle [)rinklr)~) Water ^ct approved <br />Oecember 1 (), 1 \174 WLlbl:c Law 9:1-t)23, 88 Stat. 1660). <br /> <br />HI. PHYSiCAL [MFA.eel'S OF <br />SAUNlTY <br /> <br />EvalwHion at possible salinity effects on basin <br />wnter users indicates that the ITwjor quantifiable <br />adverse effects arc primarily limited to <br />agricultural. municipal, and industrial uses. Each <br />of these uses is physically Elffected in different <br />WAYS and consequently has singular alternatives <br />available to mitigate adverse conditions. The <br />following describes the signii-icant physical <br />effects, outlines feasible alternatives used to <br />minimize losses, and presents lhe procedures <br />implemented in this study to quantify the <br />resultant impacts in preparation i'or economic <br />analysis. <br /> <br />/>.. Agriculture <br /> <br />Scllinity effects on agr-icullural uses are <br />manifested primarily by limitatrons on the types <br />of crops that may be irrigated with a given water <br />supply and by reduction of crop yields as salinity <br />levels increase. Other conditions being equal, as <br />salinity levels increase in applied irTigation water, <br />salinity levels in the root zone of the sOil also <br />Increase. <br /> <br />Because different crops have different <br />tolerances to salts in the root lone, limits are <br />placed on the types of crops that may be grown. <br />When salinity levels In the soil increase above the <br />threshold levels of a crop, progrc~ssive <br />impairment of crop growth and yield results. <br />Irrigation water which has a high percentage of <br />sodium ions may also affect soil structure and <br />Cc.lUse adverse effects on crop production. <br /> <br />H. Munieipal <br /> <br />Domestic uses comprise the major utili7ation of <br />municipal water supplies. Total hardness, a <br />parameter closely related to salinity. IS of <br />considerable interest in assessing water quality <br />effects on these uses. Increases in the <br />concentration of salinity and h3rdness lead to <br />added soap and detergent consumption. <br />corrosion. and scaling of metal water pipes and <br />water heaters, accelerated fabric wear, added <br />water softening costs, and in extreme cases, <br />abandonment of a supply. According to <br />rneasurements of hardness, raw water supplies <br />derived from the Colorado River at or below Lake <br />Mead would be claSSified as very hard. A <br /> <br />3 <br />