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<br />i' <br /> <br />~ / <br /> <br />.' <br /> <br />~ <br />N <br />CJ1 <br />w <br /> <br />improvements would be the first priority, but very little would be done beyond <br />1:..00 c1itch linings. Desalin.ation in .th.. agl;:tcultUl:al.are.as would be increased <br />to maka up the c1iff..r..nce, and canal and lat:e1:'al linings would not be affected. <br /> <br />'The array of on-farmprac1:ic..s us..d 'in: this report: is intandad to provide <br />an indication of the types and extent ofimprClvements which would have to be <br />implement..c1,. Th..re must be an accompanying cCll!llllitma.nt from the gO"lil<rnmant to <br />ass:l;s,tthe farmers and to encourage theircont1nuedusa of 1mprov...t water <br />msnagemantpractices inoluding irrigationsch..duling. <br /> <br />GrandVaUey <br /> <br />. , <br /> <br />.J ..,' <br /> <br />,'.. <br /> <br />~ . ", <br /> <br />Figure 23 illustrates the optimal cost-eff..ctive salinity control program <br />for the Grand Valley in west..rn Colorado. Tabl.. 8 pr..sents the numerical data <br />whichi. summar.izeclinFigure 23. As can, bese..n only 64 percent of the canal <br />, i' linings, lOa percent of the lat..ral linings, and 83 percent of theon-fllrm <br />salinity. recluctionshoulcl be implemented "afore den1ination should take over <br />thacontrol practice; Tablan-l in Appendix D presents th.. optimal canal <br />". ,lining program for th.. area. At th.. 64 per\>el'lt level, the Government Highline <br />Canal, th.. Qrchard Mesa Pow..r Cansl, and the Recllands Power Canal at'etotally <br />lin..d. Approdmately 60 percent of the .Grand Valley Mainline, the Grancl <br />Val~ayHighlin.., t:heMesa County Ditch, and' 67 percent of th.. combine!l'11.acI':' <br />lands ditches woulcl b.. lin..c1at this level. Whereas, 34 percent: of Price. <br />ditch, 40 perc..nt of th.. Orchard Mesa Canal ancl 9nly 12 percent of the Keifer <br />Ext:ension are lined. The remaining canals aunilt improved. The on-farm <br />program doesnotinclucle sprinkle or trickle irrigation, but c10es inclucle <br />improvamentsup .to that point. ' . <br /> <br />Low..r Gunnieon <br /> <br />. <br /> <br />i <br />"l <br />~ <br /> <br />. <br /> <br />The. elimination of winter water. from the canalS in the Lower Gunnison <br />ng:!-on in wee.t..rn Colorado gre..tly.reduce.. tile importance of the canal lining <br />program as can be seen by comparing .part:s a atlcl b in Figure 24. The. two canal <br />lining programs shown in Figure 24 areinte\lded to indicate the probable <br />maximum and minimum extent of lining construction. Th.. .praetic.. of winter <br />livestock water via the canal system contr:tbutes at least 40,OOO'Mgmfyr up to <br />an e..timatecl maximum of 75,000 Mgmfyr. The actual cas.. undoubtedl)" lies <br />.. . .bet...een th.. programs illustratacl.}n)'igure 22; however, thie only affects the' <br />"rale:c:l.ve amount of canallininss. ... , ..... <br /> <br />"', "',.'Xhe"LowerGunniElon.ie the9nlyarea "Where the v..ry,small direct c1iver- <br />sionsfrom the riv..rsand stssams "Were incluclacl. Thas..ditches are quit:e <br />small wi.th le.s then aO,.4m Is~cap~i.tY.j these weretT\!atell aa a separat.. <br />ite';'.because their cost.. would ,be .the same ~s late"..ls..However" .the.maximum <br />salt load recluction from these small c1itches w... estimated at only 8,860Mgm, <br />and ths small costs and selt contributionwer.. not significant when plotted on <br />the scale of Figure 22. Table 9 numerically pres..nts th.. optimal salinity <br />control program for the area. <br /> <br />:~"l , <br /> <br />The on-farm improvements do not include sprinklers or trickle although <br />cert..in portions of the area c10 appear to offer substantial pot:ential for <br />gTavity power..d sprinklers in orcharcls ancl 'field crops. Essentially all of <br /> <br />76 <br /> <br />, <br /> <br /> <br />~-, ,-,- <br />