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<br />" <br /> <br />j/ <br />I <br /> <br />( <br /> <br />3 <br /> <br />.. <br /> <br />_.~~. . <br /> <br />A m::::ber of Colorado squnwfish have been cllptured do"".str8.2l:l of the Dolores- <br />Colorado P..ive-r con.flue.nc2 by FWS this past j"car~-'"l .Contrary' to the conclusions <br />in the Dolores Project biological a6oess~ent~ we'believe thet this recent <br />data indicates the presence of a viable Colorado squawfish population in <br />thi.s section of the Colorado River. ~,One juvenile h'-pback chub was also <br />ta~~n in 'thih~ area dur~g the shorte~ed 19i9 sZwpling season. Arlditional <br />sD~lins s~~edu1ed for 1980 will provide more conclusive data on populations <br />of both Colorado squawfish and hu=pback'chubs in this erea. Fish collections <br />since the 1950's have doc~nted a progressive decline in squawfish nu=iliers <br />in the Colorado River. Thereforet it is increasingly i=?ortant for the <br />recove=y of the species that ~e protect and enhance river sections where <br />these fish D~~ reside, such as the section below the Dolores P~ver confluence. <br /> <br />~e proposed Dolores Project is part of the Colorado River Storage Project <br />(CRSP), w~~ch was authorized as a participating 'project of the Colorado <br />P~ver Storage Project Act of April 11, 1956. In developing this biological <br />o?iniou, '\o,Te considered the clnu1ative effects of all Colorado River CRSP <br />ucits constructed, lL~der construction, or proposed that EaY influence flows <br />abo'~e Hite }1arina. Figure 1 sho'Ws general 1.oc..atior...s end designed' net <br />deple:ions of these proj ects. <br /> <br />'. <br /> <br />~ne projects listed in Figure 1 propose &~ annual net depletion from the <br />Colorado P~ver of 546,350 acre-feet. Tp~5 total does not include e'~sting <br />ciep16tior~ associated ~~th nonrelated ~unicipa1 end ind~trial de~ds as <br />well 2E nzturel causes such as evaporation and evepotr~~piraticn. The <br />total. depletion of the Colorado River by the Dolores Projeot (l31,OOO AF) <br />"'~ -va:--y fro!:1 1 percent to 6 ?ercent during la.t.e winter" spring, and early <br />sl--e!" flo.....'"S J me.asured at Cisco. Utah. Althol!g.t~ the proj ec.t may en.~nce _...~. <br />flo.", "in the Colorado River by 1 percent d-.rring late s=r aud ,,'inter periods; <br />the depletions during the spring may negatively ~act recruitRent of the <br />endangered fishes. Recent biological infor--ation indicates that high <br />spring ~~off may enhance the reprodu~tive activity of the Colorado squawfish <br />C':iller 193::J). Tnere is not adequate data to show if high spring nmoff 1s <br />;-~'ort:;J.nt to the reproductive activity of the hur;:pbacl' chub and bonyteil <br />chub. ... ~ ~_ .' <br /> <br />.",-. <br /> <br />p~cording to the biological assessoent, the Dolor~ Project ,,'ill deplete <br />lo,,'er Dolores "f.iver spring fl""", b:r o::le-th;!.rd. The c=ulative iJ::]lact of, <br />ot"er operating CRSP I s pb.9.t. reduce or alter hip'> water levels of the <br />Colorado River ~~y severel~ reduce the reproductive success of the endangered " <br />fi5nes. Therefore, even Small depletions of ~ater from the Colorado River <br />oay be cet~ioenta1 to the s~-vival end reproductio~ of the Colorado Bqu~~~ish, <br />bO~YLcil chub, end h~back chub. In ~dditiont ~educed flo~~ prevent <br />overba~: floo~inb ~hich rQplcnisnea essenti~ nutrients &ud pro,~cies bacl~a~ers <br />,,';:cre j"'..e..-o.ile and yot:.ng-of-thc-yeer fishes seek food and sbelter. " Depletion <br />of ~ater fr~ the Colorado ~ver as a result of ~he G2SP reBen~irs ~~uld <br />cl' -',ate peak flo",s that create eccying =d bec:bmter habitat tbat "ppear <br />::0 be i.:::?o::ta.:::.t to sque:....iish end hu:::::?~ac.k C~Ub5 Hnd t:.a)" also be iI::?Ort~"1t <br />to bo~y~cil chubs. <br />