WSPC01284

• File Number: 8210.720
• Description: Colorado River Basin Organizations-Entities - US Bureau of Reclamation
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 11/1/1944
• Author: DOI-BOR
• Title: Report of US Bureau of Reclamation - Colorado River Basin
• Water Supply Pro - Doc Type: Report/Study

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3. Basin Water Supplies (Cont1d).

4.500,000 aore feet. the unconsumed outflow from the United States
will approximate 9.331,000 acre feet annually, plus or minus the
differences between tributary oontributions and ohannel losses be-
tween we Ferry and the international boundary.

~

4. Upper Basin Supplies and Depletionsl

Present depletions in the Upper Basin. and the depletions of all
potential projeots in the Upper Basin desoribed in the Report, are estimat-
ed for the period 1931-1940 as followsl

Present Depletions. ino. exportations
Potential Depletions.
, Irrigation within Basin
Exportations
Reservoir Losses
Sub-'rotal

Ac re Feet
2.440,000

(5)

1.845.000
1.792.000
831,000

4.468 ,000
6.908.000

Total

The average armual flow at Lee Ferry during 1931-1940. had no up-
stream diversions been made, is given in the Report as 12.2B4.000 aore feet
per year. Atter deduoting from this figure the 7.500.000 aore feet annual-
ly allooated to the Lower Basin, only 4.734.000 aore feet would remain for
the Upper Basin. Hence the Bureau of Reolamation oonoludes. that the full
Upper Basin depletion of 6,908 ,000 aore feet during a drouth cyo Ie such as
1931-1940, whioh would result from the potential projects desoribed in the
Report. could only be made if. at the begi:rming of the decade, the Upper
Basin had holdover storage sufficient to permit of releases averaging
2,174.000 aore feet annu,ally throughout the ten-year period.

The Report explains that its estimated potential depletions do not
inolude all possible projects in the Upper Basin, and mentions the fact that.
among projeots omitted. are the Colorado River-Great Basin diversion and the
Cisc o-Thompson project.

o

With more abundant v.ater available in periods of normal precipita-
tion (i.e.. all periods except drou;bh oycles). Upper Basin oonsumptive uses,
particularly diversions for export, evaporation from fuller reservoirs. and
filling of reservoirs for lean years, would exoeed the quantities shown
(i.e. 6,908.000 aore feet during 1931-1940) by more than enough :to make tot-
al depletions reach 7,500,000 acre feet yearly.

.'

NOTE (4). The reoorded flow at U3e Ferry is given in the Report (po 226) as
10.142.000 acre feet per year during 1931-1940. We presume this
figure was used to arrive at the virgin flow during 1931-1940 of'
12,234,000 acre feet. above mentioned. Records heretofore adopt..;
ed by the Bureau of Reclamation and this offioe show the reoorded
flow at tee Ferry (ino. Paria R.) averaged 10,167,000 acre feet,