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<br />Diatri.bution.
<br />
<br />';<iMPACTS AND AGREEMENTS BErWlCEN CERTAIN s'rA'l'ES, 31
<br />
<br />Colol'n<lo: .
<br />GL'nll (1___ .<_____ ____~ _____ ________________ ____________
<br />~~~~C;~~l_n~~~~~~~~-_-_~~~~-~~~-_~~~~-_-_~~-_-_~~~_=-_~.~~-~~~============
<br />
<br />Acre-ff'A!t,
<br />6,425, 000
<br />2,002,000
<br />1,757,000
<br />
<br />10,184,00U
<br />The il'rig-lLble IHUds of western Colorado are not extensive ellollgh to reQuire
<br />or clemallll even a cOllsidN'alllc purl: of the total waler sllpply passIng from
<br />Colorado. While there are approximately 25,000,000 acres of land ill tile
<br />wC:'il(>l'n lhlrd of Coloraclo in the Colorado Riyer umlin, probably not to exceed
<br />2,000,000 to 3,000,000 acres of Lhis land will ever he iL-rignted, since there arc
<br />vast ::trCllS of high plll{.CUlIS aIltI lllOuutnins !lot suitahle for cultivation There
<br />:1r(~ also considerable areas of tine land suitable for cultivation wbich will
<br />alWAys 1'emain llnuroken because U\ey are so located that Lhere is no udjacent
<br />water supply, 01' the cost of constructing reservoirs filld callnh Lo supply them
<br />will be r.xcc~si \'~.
<br />'l~lle 1n(!llllCC thnt Colorndo. New Mexico, Utah, Qnfl Wyoming d~sire to nvoid
<br />(in the cllHstl'uction of a lArge reservoir on the lower Colorado River) is the
<br />grunting of n }Jl'cferentinl 01' priority woter right to sllch a reserroir that will
<br />ultimalely he felt when these States attempt to inigale the undeveJopeu arable
<br />Inl1ds within theil' bOl'l1ers, JUl:\t. sneh water problems confront Colorado water
<br />users to-tiny in the San Luis Valley 011 the B.io GrancIe, in Nortll Park on the
<br />North PJill.te, and iu Middle Park (t.rnmilnonutain diversion) on the bead-
<br />wllh'll'S ot t.hc GWlld llivcr, where rights of way over Govel'Hrnent land!; have
<br />been denierl by t.he Interior Dejmrtment without justiti.eat:on.
<br />Of a possible 2,000,000 acres that <i:;lorndo Ill11Y ultimatcly irrigate from tribu-
<br />taries of rhe Colorado River, only '50,000 acres arc now irrigated. III com.
<br />parison wilh this HI'ea Lhe annual run-oft 01' stream-now of weste1'l1 Colorado
<br />which pllf-;Ses now l1llU~ed nc!'OSS the SLate Iille is over 10,000,000 (Lcre-feet after
<br />serving thcHe lands,
<br />'I'lle toLflt Det delllflll(l.s 01' con~umlltive use of wuter for 2,000,000 li('l'('S will
<br />fillproxinwte, ancllH'obably not exceed, over 3,000,000 acre-fl~et, since ult.imately
<br />large volumes of \I"aler used for irrigation return to the strcams as seepage
<br />or retUl'n wuteI',
<br />liTigation iuvestigal:iolls show that generally frOIll 20 to 50 pel' cent of the
<br />water applied to lanel for irrigation ultimately rE'tlll'llS t.o t:he stream channel.
<br />~('his is \Vcll iIlustmted in lJ1(! irrigation history of the Nort.h and South PlattR.
<br />lEvers, 'l'he nnl1\H\.l meas\\t'N1 ret.urn flow of the South Platt.e Rivet' in
<br />Colornclo bct.ween La Snlle and .Tulesburg, n distnnee or 150 miles, now HIllOUlll~
<br />to 800,000 Hcre-fcet Ilunually, Hecords of return tlow secured in 1000 for the
<br />.<;awe river Rcctioll show t.he gain at that time to have anI;',' been 350,000 ncre-
<br />",lQ;:)N ',-npl[d rr~,roN pun "o^-M. '1I8[1HLM naaAqaq '.I8'\IH <JllUld m,WN aln uo 'NpJ
<br />the measured retul'll flow in 1918 amounted to fLpproximately 400,000 ncre-
<br />feet, and t.he recol'tls of the Reclumntion Service show that the 90,000 aCL'e8
<br />then undl'l' irl'igntion from the Int.erstatp. Canal were contributing 1.5 acre-
<br />feet pm' uCI'e per anuum of return flow water from irrigation to the various
<br />formerly el1')' tributaries of the North Platte River.
<br />'l'l1c ahove statement.,:; find otheL' well-known enginecring facts fire the basis
<br />for tlte sL:l{ement that the irrigation of large areas of lanel on the henllwaters
<br />of 0111' stl'nlUllS builds up silently large undCl'ground reservoirR which equalize
<br />through seepage Of relurn wntCl' the flow of our strefllns which odinarily dis-
<br />charge 70 per cent of their annual now in the Illonths of April, M:lY, June, aDd
<br />July. .~..;jp()"',...
<br />The bencficial effect of roturn wnters from irrigation of the '~00Q. acres
<br />now irriga\.c:d in We~lC:l'n Colorado \5 partly rna!;kl.~{l by the building up of
<br />undei'groun,1 reservoirs on lands, but. recently irrigated and partly through
<br />diversion and reuse Oil Ilew lands. Ten to 15 years may elapl'le before the
<br />full beneJH of suclIl'eturn watel's is evident in the low(>r YmDps, Whit.e, Grand,
<br />Dolores, anrl San .Tuan Rivers. Wit11 2,000,000 ncrel'l ultimately irrigated in
<br />Wes.tel'n Colorado und additional large nreas in ULah, New Mexico, ancl Wyo-
<br />111ing, the ht..:lleDts to the lower Colorado River from l'Ctlll'l1 water .will not only
<br />be visible, hut sholl1cl he quite marked.
<br />The low('1' States of ArizOlHl. and Culifol'nifl want. the peaks knocJ{ed off. the
<br />floods and hetttll' cqunlizccl winter flow, both for power ancI irrigation. Irriga-
<br />tion 011 the hea.dwalers in time, will, therefore, automatically better conditions
<br />on t,lIe Lower Colomao.
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