WSP00601

• File Number: 8273.300
• Description: Colorado River Basin Salinity Control - Federal Agencies - USGS
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/1996
• Author: USGS
• Title: Trend Analysis of Selected Water-Quality Data Associated with Salinity-Control Projects in the Grand Valley - in the Lower gunnison River Basin - and at Meeker Dome Western Colorado
• Water Supply Pro - Doc Type: Report/Study

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A significant decrease in chloride and
sodium concentrations in the White River down-
stream from Meeker Dome indicated that the well
plugging in 1981 was successful in stopping much
of the discharge of saline water from the wells.
Chloride and sodium concentrations have not
changed in the White River at Meeker or down-
stream from Meeker during water years 1982-95,
indicating that the well plugging has remained
intact.

INTRODUCTION

The Colorado River is used for municipal and
industrial water for more than 18 million people in
seven Western States and provides irrigation water for
about 1.7 million acres of land (U.S. Department of
the Interior, 1993). Because of these uses of water,
dissolved solids, or salinity, has increased in the
Colorado River. The terms "salinity" and "dissolved-
solids concentration" often are considered synony-
mous, and in other reports on the Colorado River
Basin, the term "dissolved solids" often is referred to as
salinity. Dissolved solids can have adverse effects on
crops and on municipal and industrial users, especially
in the lower part of the basin. In response to the
Federal Water Pollution Control Act of 1972 (Public
Law 92-500), the seven States in the Colorado River
Basin adopted numeric dissolved-solids criteria for the
lower Colorado River. The States suggested that the
Bureau of Reclamation (BOR) plan and implement a
program to maintain dissolved-solids concentrations at
or below existing levels to allow upper basin States to
develop their water. Also, dissolved solids in the
Colorado River were a factor in relations between the
United States and Mexico. To meet treaty obligations
with Mexico and to decrease salinity effects in the
Colorado River Basin, the U.S. Congress passed the
Colorado River Basin Salinity Control Act (Public
Law 93-320) in 1974. The act authorized construction
of 4 salinity-control projects and the planning of
12 other projects in the Colorado River Basin by the
U.S. Department of the Interior (DOl). One of the
authorized construction projects was the Grand Valley
Unit, which concerned irrigation in the Grand Valley in
western Colorado (fig. l). The Lower Gunnison Basin

Unit, which concerned irrigation in the Uncompahgre
Project and other areas in the lower Gunnison River
Basin (fig. l), and the Meeker Dome Unit, which con-
cerned dissolved-solids discharge into the White River
(fig. 2) from abandoned oil wells, were authorized for
planning under the Salinity Control Act of 1974,

The Salinity Control Act of 1974 directed the
Secretary of the Interior to cooperate with the Secretary
of Agriculture in implementing on-farm improvements
as part of salinity control. In 1984, an amendment
(Public Law 98-569) to the Salinity Control Act was
signed that provided a separate authority for implemen-
tation of salinity-control projects in the Colorado River
Basin by the U.S. Department of Agriculture (USDA),
The USDA has done salinity-control work in the Grand
Valley and Lower Gunnison Basin Units. Therefore,
the salinity programs in these two areas have consisted
of two parts: (1) The BOR has directed improvement
of the water-distribution systems; and (2) the USDA
has been responsible for the on-farm improvements.

In a review of the Salinity Control Program in
1993, the DOl was concerned that the effects of the
salinity-control projects on dissolved solids in the
Colorado River Basin had not been adequately deter-
mined or documented. To address concerns raised by
the DOl, the BOR submitted a study plan to determine
effects of the salinity-control projects in the Grand
Valley and in the lower Gunnison River Basin on
dissolved solids in the Colorado River.

Work on the Meeker Dome Unit was completed
in 1981, and initial analyses of the effects of the project
(CH2M Hill, 1982; Bureau of Reclamation, 1985b)
indicated that the project had decreased dissolved-
solids loading to the White River. The salinity-control
work at Meeker Dome needed to be evaluated to verify
the initial conclusions and to determine if salinity con-
trol had remained effective since 1984.

In 1994, the BOR requested the U.S. Geological
Survey (USGS) to examine trends in dissolved-solids
data for the Colorado and Gunnison Rivers to address
concerns raised by the DOL The BOR' also requested
the USGS to examine chloride and sodium data for the
White River to verify the effectiveness of the salinity-
control project at Meeker Dome.

2 Trend Analysis 01 Selected Water-Quality Data Associated With Sallnlty-Control ProJects In the Grand Vallay,
In the Lower Gunnison River BaSin, and at Meeker Dome, Western Colorado