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<br />00D397 <br /> <br />-8- <br /> <br />. <br /> <br />Lower Basin, - that some of the waters of the Colorado River system are be- <br />ing used "outside" above Lee Ferry, whereas all uses are "inside" below Lee <br />Ferry. Such an implication. which is not in accordanoe with f<\ots. and <br />which results solely from the distorted boundaries of the adopted "Bnsin," <br />is unfair .to the States of the Upper Division. Colorado suggests that the <br />Report be revised to show the Mlounts of water involvei. in present and po- <br />tential diversions from the Colorado River system uelow Lee Ferry for use <br />outside the natural basin, that such quantities be listed individually and <br />be s\lIlllllarized separately frcm uses within the natural basin, and be desi!;'" <br />nated "export diversions," the SlUIle as thos e above ~e Ferry; and that the <br />export diversions above and below Lee Ferry be compared in aJOOunt in the <br />basin-wide summaries whioh Colorado su~ests be added to the Report. <br /> <br />lB. The Report presents estimates of so-called "vir!;in flows," vtlioh <br />are not defined, and of so-oalled "depletions," which are inndequntely de- <br />fined, and says, at page 61 "The Compaot divided the water on the basis <br />of virgin flows." Colorado suggests that the Report be revised to elimi- <br />nate all comparisons between so-oalled "virgin flows" and oompact allooa- <br />tions of water, and all inferences that the two are directly comparable; <br />and in defining depletions, aooount be taken of changes in stream losses; <br />and further, that the Bureau not assign depletions or savings in stream <br />losses to individual projects. This suggestion does not mean that so- <br />called "virgin flows" should not be evaluated or appear in the Report, <br />for that term, if carefully and fully defined and consistently emplcyed, <br />is useful in analyzing streamflow. water supply, and related data. At <br />the same time the Report should not state or infer that the "virgin flow" <br />quantities are the same as or are directly comparable with tltl waters of <br />the Colorado, .River system that have been and are hereafter to be appor-' <br />tioned by the Colorado River Compact. <br /> <br />. <br /> <br />19. While "virgin flows" are not defined in the Report. the quanti- <br />ties therein shown have been calculated as averages for periods of years. <br />conunonly for the period 1931-1940 for streSJll gaging stations above Lee <br />Ferry, and commonly for the period 1897-1943 for stations below Lee Ferry. <br />Bureau of Reclnmation representati ves ss:y that, in the revised final <br />draft, average values for both periods vd 11 appear for stations in both <br />basins. Colorado ss:ys that the Report as a whole should be based on long- <br />time averages. The purpose to be served by virgin flow estimates, mani- <br />festly, is to foreoast the average conditions to be anticipated in the <br />future, Hith respect to natural phenomena such as precipitation, and <br />the runoff and streamflows resulting therefrom, all planning for the fu- <br />ture is necessarily based on what has occurred in the past. The best <br />evidenoe of what to expect in the future must be based on the available <br />records of the past. Since neither the occurrence nor the sequenoe of <br />flood and drouth seasons end cycles of years can be forecast with ac- <br />curacy, Colorado suggests that virgin flow quantities appearing in the <br />Report should all be based on the same period of years. in order that <br />comparisons ms:y be made one with another; and .that said period of years <br />should be 1897-1943. if that be the longest for which streBJUflow records <br />are available. or can be caloulated from related information. That per- <br />iod is of sufficient length to insure that changes in average values, as <br />additional reoords become available, will probably be only of minor <br />