|
<br />00178!
<br />, t
<br />
<br />-11-
<br />
<br />(1) The word "doplcted" here refers to nnturnl losses, since by
<br />definition there v.ere no mnn-made "depletions" under virr;in conditions,
<br />and miGht better read "reduced" or "d1Jninished."
<br />
<br />(2) A "growinr; stream" down to the Illnck Cnn~ron seotion does
<br />not mean tho.t naturnl losses nra absent nbove th"t point, or r.IO.Y be ignor-
<br />ed as in the Report. On the oontrnry it menns only that inflows to tho
<br />min river, or oontributions from tributnry strenms and areas, are Great-
<br />er in nmount than the qunnti ties of water lost in oonveyanoe. Similarly,
<br />o losing river in the desert ragion does not menn thnt thore ware no
<br />trihutary contributions under virr;in conditions, or that they me.y be dis-
<br />regnrded. Instee.d, it means that Il11turnl losses from the me.in-river
<br />channels were ('reater in amount than the tributary inflows (except at
<br />times of flood).
<br />
<br />(3) Ilith "virgin flows" of 2,202,000 noro-foot at Phoenix nnd
<br />l,27l,OOO acre feet at Doma, the oonveyanoe loss would be 1,011,000 acre
<br />foet plus all the virr;in tributnry inflow to the river seotion.
<br />
<br />(4) The indioated net e;e.in from Lee F'er ry to Laguna Dam, ac-
<br />oordinG to the above te.ble, is lGO,OrJO nore feet. Sinoe the contribu-
<br />tions reported from 14ttle Colorndo e.nd Virgin Rivers togethor amount to
<br />6413,000 aore feet, the tnbla implies thnt nntural losses under virgin
<br />oonditions were 468,000 aore feat. ColoradO questions the aoouro.oy of
<br />the estimates for the two reported tributerie s, and says that mi sce llane-
<br />ous tributary drninaGe arens Ylere iGnored. Under so-onlled virgin oondi-
<br />tions the tributary oontributions botween Lee Forry and Lagunn Dam (as
<br />estimnted by Colorndo engineers) e.verar,ed 495,00(\ 'lore feet from the Littlo
<br />Colorado River, 392,000 aore feet from the Virr;in River, 413,000 aore feet
<br />from miscellaneous drainnGos betwoen tee Ferry and Bouldor Dam, and 200,000
<br />acre feet from miscellaneous strewns (includin(; \,Jilliams !liver) nnd nrens
<br />betr~en Boulder Dam and Lar;une. Dam. Assuming that total ficure of 1,500,000
<br />acra feet, of the net r;ain 'between Lee Farry nndLaguna Dam is 100,000 acre
<br />feot, as shoym in the nbove tnbla, the naturnl conveyance loss would aver-
<br />aGe 1,320,000 acre feet nnnually along that river section under virGin
<br />o onditions.
<br />
<br />(5} From the instnnoos nbovo montlonod it is nppo.rcnt that
<br />nnturo.l conveynnce lossoo in the Colorado River Basin involve substantinl
<br />qunntities of wter, and it seems self-evident that such losses under so-
<br />en lIed "virGin conditions," when streamflows were max1Jnum and wholly un-
<br />!'or:;"lll'bod, would hnve boen r,rea'ber tlwn thooe oboervod and cnloulc,ted
<br />from l'ocord" durin(', tho historic poriod. ColoradO sUGr,eds thnt estimo.tEls
<br />of nrcturo.l losses should be mrcdEl by the B\,renu of Reclamntion, and should
<br />appoar in the Roport, oovorinr; so-oalled virgin conditions, or the condi-
<br />tions of tho period of reoord, or both. As estimnted by Colol'ado enGi-
<br />neers durinr; the poriod 1901J-19L12 (whon man-mode depletions avero.ged
<br />1,')72,000 nore feet per yaBr nbove Lee Ferry, nnd 2.911,000 aore feet be-
<br />low lee ferry, and when the recorded flow at the IntElrnntional Boundary
<br />nvornGed 12,683,000 ncre foet annually). the natural oonveyanoe losses
<br />nverrcged 870,000 aore fElet abova LEle Ferry, nnd 2,640,000 aore fElet below
<br />we Ferry, or totalled 3,510,000 o.ore foot nnnually in the Colorndo
<br />
|