WSPC02026

• File Number: 8200.700
• Description: Colorado River Basin General Publications - Augmentation-Weather Modification
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 5/2/1983
• Title: Preliminary Evaluation of the Ongoing Salinity Control and Related Programs in the Colorado River Basin
• Water Supply Pro - Doc Type: Report/Study

GQOO'71

only. In general, higher unit costs are being encountered for those units
farther out on the planning horizon.

PROGRAM OVERVIEW

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figure 6 displays the 1995 Projection Windows of TDS at Imperial Dam based on
the 1981 forum Review. The upper window shows conditions without any salinity
controls or augmentation programs in place. Under this condition, future TDS
could fall anywhere in the area bounded by high and low depletion rates and
high and low yields for the river system. The lower window shows projected
TDS with only Reclamation WQIP salinity control units in place (no snowpack
enhancement) under the same boundary conditions. Under optimal conditions of
high runoff (yield) and low depletions or development, the 1995 projected TDS
conditions could meet the TDS numeric criteria.at Imperial Dam. However,
according to the relative window area shown above the TDS numeric criteria,
projected TDS will exceed the numeric criteria under most other runoff and
depletion conditions, even with salinity control.

figure 7 is a graphical display of CRSS salinity projections at Imperial Dam.
These projections are based on current state-of-the-art computer modeling of
the Colorado River Basin and have been released to the pUblic in Progress
Report No. 11.

Projected TDS is shown only for the years 1995 and 2010 to provide a direct
comparison of TDS with and without USBR and USDA salinity controls or
snowpack enhancement projects. Hydrological variations of runoff (yield) are
shown as a range on the bar graph. The low salinity range represents high
flows and the high salinity range represents low flows. In addition, the
average 15 million acre-feet yield used by CRSS (fig. 7) corresponds to the
hi9h runoff/yield considered by the forum (fig. 6). In contrast to the forum
projections (fig. 6), the CRSS projections were derived based on only one
rate of depletion or development scenario. This rate is compared to the
depletion rates projected by the forum in figure 8. For the 1995 projection,
there appears to be a possibility of satisfying the TDS numeric criteria
without any salinity controls under conditions of the most favorable hydrology.
By 2010, however, projected TDS conditions without salinity control will
exceed the TDS numeric criteria standard for all hydrological variations.
For both the 1995 and 2010 conditions with salinity controls, and without
snowpack enhancement, it is apparent that there 1S about a 50 percent chance
for meeting the TDS numeric criteria standards for the full range of future
hydrology variations in the basin.

CRSS Simulation

A second set of simulations were run using CRSS to evaluate cumulative
effects of the full water quality improvement program and a snowpack enhance-
ment program. The simulations each involved 15 traces for a 58-year period,
from 1983 to 2040, the year in which Upper Basin depletions peak at 5.8 million
acre-feet per year. The scenarios consisted of the following:

1. BASE case. - Projected depletion schedule with no salinity control
projects or snowpack enhancement.

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