7431

• UCREFRP Catalog Number: 7431
• Author: Colorado River Salinity Program Coordinator.
• Title: Salinity Update.
• USFW Year: 1989.
• USFW - Doc Type: Denver, Colorado.
• Copyright Material: NO

High salinity concentrations
result from two general processes:
salt loading and salt concentration.
Salt loading increases the amount of
salt added to a given amount of
water, and salt concentration
decreases the amount of dilution
water available for a given amount
of salt.
Specifically, salt loading in the
Colorado River system results in the
addition of mineral salts from
natural and manmade sources. Salt
concentration results in the rise in
salinity through beneficial
consumptive use of waters and
associated streamflow dr iletions in
the Basin that concentrate the salt
burden into a lesser volume of
water. Generally, the application of
irrigation water results in increased
salt loading because of salt leaching
and the concentrating effects of
consumptive use. The total salt
concentration in the river fluctuates
annually with the overall Basin
water supply.
A
t
I
M
P
r
T
f
D
a
m
M
9
The Colorado River, at its
headwaters in the mountains of
north-central Colorado, has a
salinity (dissolved minerals)
concentration of only about
50 mg/L (milligrams per liter). The
salinity concentrations
progressively increase as the river
flows downstream as a result of
water diversion, evaporation from
reservoirs, and salt contributions
from a variety of sources. Recent
record-high flows have flushed and
filled the major reservoirs, resulting
in significantly lower salinity levels
at Imperial Dam - from an annual
average of 826 mg/L in 1982 to
621 mg/L (provisional) in 1987.
Without control measures, however,
the concentration is projected to
increase, following the overall rising
trend shown in figure 2, possibly
reaching a level of 966 mg/L* at
Imperial Dam by about 2010.
* The current projection is from 1988
Evaluation of Salinity Control Programs
in the Colorado River Basin.
1000 ...................................
WO/Controls
950 ............................::.'
900 Standard
850 ..............."............I.

800 J ......... Al ....
750 .......................................
700 ...... ....................................
650 .... :' ......................................
600
L 1985 1990 1995 2000 2005 2010 2015 2020
Years
Figure 2. - Salinity projections with and without further controls 10/88.