BOARD01635

• Board Meeting Date: 3/26/1945
• Description: Table of Contents and Minutes
• Board Meetings - Doc Type: Minutes

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Lower Basin, - that some of the waters of the Colorado River system are
ing used "outsidett above Lee Ferry, whereaB; aU'uses are ttinside"beiaw:
Ferry. Such an implication, whioh 1s not 1n aocordance 'with facts, and
which resultlf' solely from the distorted boundar1ee of the adopted ttBaSin "
is unfair to the State If of the Up~r. Division., Colorado suggests that thlt
Report be revised to show the amounts of water involved in present and po..,
tential diversions from the Colorado River system below Lee Fsrry for un'"
outside the natural basin; that such quantities be listed individually .
be sUll11llarized separately from uses within the natural basin, and be desig_
nated "export diversions, II; the same as those above Lee Ferry; and that t '
export diversions above and below Lee Ferry be compared in amount in the
basin-wide summaries which Colorado suggests: be added to the Report.

18. The Report'presents sstimate5 of so-oalled ttvirgin, flows," Which
are not defined, and of so-called "depletione," which are inadeqQately de-
fined, and says, at page 6, "The Compact divided the water on the basis
of virgin fIONS." Colorado suggests that the Report be revised to elimi_
nate all oomparisons between so-oalled "virgin flows" and oompaot alloca-
tions of water, and all inferences that the two are directly canparable;
and in defining depletions, acoount be taken of changes in stream losses;
and further, that the Bureau not aesign depletions or savings in stream
losses to individual projects. This suggestion does not mean that so-
oalled "virgin flows" should not be evaluated or appear in the Report,
for that term, if carefully and fully defined and oonsistently employed,
is useful in analyzing streamflow, water supply,' and related data. At
the s8llle time the Report should not state or infer that th8 "virgin flow"
quantities are the seme as or'are directly cQllparable with the waters of
the Colorado River system that have been and are hereafter to be appor-
tioned by the Colorado River Compaot. '

19. While "virgin flows" are not defined in the Report, the quantities .
therein shown have' been oalculated as averages for periods of years, ':
commonly for the period 19~1-194o for stream gaging ete.tions above Lee Ferry, .':
and commonly for the period l897-l94~ for stations bel~ Lee Ferry. Bureau
of Reo18lllation representatives say that, in the revised final dra1't,
average values for both periods will appear for stations in both basins.
Colorado says that the Report as a Whole should be based on long-time
averages. The purpose to be serve!!- or vtrg.1.n n9";,.~st~!I1!l.tes, mani-
festly, is to forecast the averagecondltions to be llnticipated in the
future. With respect to natural phenamena such as precipitation, and
the rlDloff and streamflows resulting therefran, all planning for the fu-
ture is neoessarily based on what has occurred in the past. The best
evidence of What to expeot in the future must be based on the available
records of the past. Since neither the o,ccurrenoe nor the sequenoe of
flood and drouth seasons and cyoles of years oan be foreCast with ao-
curaoy, Colorado suggests that virgin flow quantitie. appearing in the,
Report should all be based on the same period cf' years, in order that
comparisons may be made one with another; and that said period of years
should be 1897-1943, if that be the longest for m ioh streamflow records
are available, or can be oaloulated from related inf'onnation. That per-
iod is of' suffioient length to insure that changes in average valuee, as
\additional records beoome available, will probably be only of'minor