WSPC06972

• File Number: 8283.100
• Description: Colorado River Computer Models - Colorado River Simulation System - Reclamation - CORSIM
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 9/1/1973
• Author: DOI-BOR
• Title: Application of a River Network Model to Water Quality Investigations for the Colorado River
• Water Supply Pro - Doc Type: Report/Study

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define an element for the introduction of any changes from the
present conditions. This eliminated the need to recompute bound-
ary inputs for each run.

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It is noted that the modified historical inputs represent but one
hydrologic sequence. Stochastically generated inputs would allow
the introduction of measures of confidence (see interpretation of
results below).

(2) Initial salinity conditions - The effect of the initial
reservoir salinity persists for a portion of the run. Conse-
quently, statistics for the entire run reflect the initial con-
di tions. When the ir.lposed changes deviate radically from those
for the base condition, a definite trend of either increased or
decreased salinity results. To remove this trend and estimate
ultimate effects, each set of conditions was run twice. The
first run used the flow-weighted 1970 historic salinities (equal
to present modified data) for each reservoir, as shown in the
next subsection. The second run employed the flow-weighted con-
centrations for the last year of the first run. This topic is
more fully discussed in the section "Transient Effect of Initial
Salini ty."

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(3) Initial reservoir contents - The initial reservoir volumes
are shown in the following tabulation. Volumes for Lake Powell
and Lake Head correspond to the historic end-of-month contents'
for December 1970. For Lakes Hohave and Havasu the initial con-
tents were chosen as the mean monthly historical content of the
1967-1970 period. These values were considered as representative
initial contents that are likely to exist for all runs.

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Reservoir

Initial salinity
(ppm)

625
743
758
758

Initial content
(1,000 acre-feet)

14,127
19,189
1,582
568

Lake Powe 11
Lake ~Iead
Lake ~Iohave
Lake Havasu

(4) Storage changes and depletions - Comparison of results based
on a run in which reservoirs filled and spilled with those in
which reservoirs were dralffi down to dead storage levels could be
very misleading. Consequently, depletions were adjusted to prevent
excessive changes in storage for the entire system (i.e., all four
reservoirs) during a given run. This was accomplished by adjusting
flows at Imperial Dam and those for the Central Arizona Project
when it was included in the runs. The lower limit at Imperial was
never allowed to go belOl< 5.7 million acre-feet annually, a figure

to

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