WSP03774

• File Number: 8273.800.10
• Description: Colorado River Basin Salinity Control - Federal Agencies - Joint Reports
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 12/1/1990
• Title: 1990 Joint Evaluation of Salinity Control Programs in the Colorado River Basin
• Water Supply Pro - Doc Type: Report/Study

I-"
W
,.':::..
0)

Program Evaluation

Background and Assumptions

Salinity concentrations of the river have
fluctuated widely over the period 1941-1989.
Salinity concentrations generally decrease in
periods of high flows and increase in periods of
low flows. Figure 2 shows the annual flow of the
Colorado River at Imperial Dam and the
corresponding annual salinity concentrations.

Figure 3 provides a historical perspective,
numeric criterion, and the projections at
Imperial Dam without further salinity control
actions, Without the recommended controls, the
salinity at Imperial Dam is expected to increase
significantly over the next 20 years. Current
salinity projections show that an additional salt
load reduction of about 1.280 million tons per
year is needed to maintain total dissolved solids
(TDS) levels at the numeric criterion of 879
mgIL at Imperial Dam. A total salt removal of
1.464 million tons per year is needed by the year
2010.

The 1990 evaluation was completed using
modeling results from the Colorado River
Simulation System (CRSS). The base condition
on which the computer simulations were made
include the following salinity control projects:
Grand Valley, Meeker Dome, Uinta Basin,
Las Vegas Wash, Lower Gunnison I, Big Sandy
River, and BLM well plugging. These projects,
or portions thereof, are removing approximately
183,500 (Jan. 1990) tons of sa It annually from
the river system, as shown in table 1.

The 1990 base condition was modeled using the
January I, 1990, reservoir starting conditions.
Projections of future salinity conditions on the
Colorado River are derived from 15 sequences of
historically based hydrology. Depletion
projections as of January 1990 were developed
jointly by Reclamation and the Forum.

Moderate variations in the salinity levels in
impoundments like Lake Powell and Lake Mead
and at Imperial Dam can be ascribed to several

900 20
Salinity :\ r, r,
" I \
~ 850 I \ 1 \,
: \ I \J 18 'C'
'" I I I " ..
.E. CD
I I ....., I' ...
, I /\'
c: 800 I I '" " 16 ~
0 I I \ I I 8-
.~ ' I I I a;
, I "
, I I I
c 750 : l l V I 14 .!,
l'! ' " I CD
c: : L.I . l;
8 I 12 ~
.~ 700 , ;!!
,
.5 , \ 10 I
m , I , 1
0; 650 I, \ , .
y 8.8
::l \
c: ,
~ I 0;
600 I , ::l
\ I c:
V 60lf
550 4
1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990
Years

Figure 2.-Historical flows and salinity concentration at Imperial Dam.

5