WSP01995

• File Number: 8272.300.50
• Description: Colorado River Basin Salinity Control Advisory Council
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 10/1/1998
• Author: USDA
• Title: Colorado River Salinity Control Program - Federal Accomplishments Report for Fiscal Year 1998
• Water Supply Pro - Doc Type: Report/Study

COLORADO

i~
4

o
en
Ul
....

Irrigation I;>rainage Study of the Lower Gunnison and Grand Valley Area A reconnaissance
investigation of the Uncompahgre Project was done in 1987-88 and a report published in 1991.
That study'focused on selenium problems at Sweitzer Lake. The reconnaissance investigation
also collecied selenium and other trace-element data and salinity data for the Uncompahgre and
Gunnison Rivers. The results of the reconnaissance study indicated that the Uncompahgre
Project waS a significant source of selenium. A detailed study was done in 1991-93 to determine
source arellS of selenium and geochemical processes affecting selenium concentrations in water
and to determine if selenium was adversely affecting fish and migratory birds. The Grand
Valley was a known source of salinity, and was suspected that it may be a significant selenium
source; therefore, the Grand Valley was included in the detailed study. Various surface-and
ground-waler, mineralogic, geologic, and biological data were collected for the detailed study,
and the data were published in 1994. An interperative report for the detailed study was
published in late 1996.

')
"r
,-1

The Natio1\al Irrigation Water Quality Program (NIWQP) remediation planning efforts for the
Uncompahgre Project and Grand Valley continued during FY98. A study team headed by the
Bureau of Reclamation (BOR). with members from the U.S. Geological Survey (USGS) and the
U.S. Fish *nd Wildlife Service, directs the remediation planning efforts. The study team has
considered: salinity-control projects as a possible remediation tool for selenium, but the effects of
canal and 11Iterallining on selenium loading has not been directly documented. In conjunction
with the C9lorado River Basin Salinity Control Program and the Uncompahgre Valley Water
Users Association, NIWQP partially funded a small-scale salinity control project in Montrose
Arroyo nelj,r Montrose. That project plans to line about 7.5 miles of laterals, and the USGS and
BOR are collecting field data to document the changes in salt and selenium loads in Montrose
Arroyo.

'3

1i'
.,
'"";

'l

Decreases in Salinity Loads in Four Washes in Grand Valley, Colorado

The U.S. Geological Survey released a Fact Sheet in January 1998 describing decreases in salt
loads in four washes that drain major irrigated areas in the Grand Valley. The study compared
salt loads in the four washes for a period prior to salinity control to the loads in 1991-1996. The
total salt load in the four washes during 1991-1996 was about 72,000 tons per year less that for
the earlier period. Various salinity-control projects for the Grand Valley Unit were probably a
major factor in decreasing loads in three of the four basins.

Trends anJl Changes in Dissolved Solids and Streamflow in the Colorado River Basin
Upstream .Crom Lake Powell .

f
"

In FY98, t\1e U.S. Geological Survey, in cooperation with the Bureau of Reclamation, began a
trend study of dissolved solids and streamflow in the. Colorado and Green River Basins upstream
from Lake 'Powell. Trend analysis was done for 60 stations, and preliminary results indicate that
large-scale downward trends in salinity have occurred. Many of the trends do not appear to be
related solely to streamflow trends, which suggests that salinity inputs have changed. The first
draft of the report has been completed, and the report is scheduled for publication in FY99.

.
.
~

9