WSP06951

• File Number: 8273.300
• Description: Colorado River Basin Salinity Control - Federal Agencies - USGS
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/1985
• Author: USGS
• Title: Ground-Water Contribution to the Salinity of the Upper Colorado River Basin
• Water Supply Pro - Doc Type: Report/Study

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The dissolved-solids concentration was about 1,400 mg/L in Big Alkali
Creek (site 41), but the flow was only 0.25 ft3/s. Big Alkali Creek drains
predominantly the Dakota Sandstone and Upper Cretaceous shales in
hydrogeologic unit 7. Sunnyside Creek (site 42) had a dissolved-solids
concentration of about 610 mg/L. Areas of Mancos Shale are in the upper
reaches of the drainage, and the Dakota Sandstone is predominant in the middle
and lower reaches.

Dissolved-solids concentrations ranged from about 94 mg/L to 249 mg/L in
Derby Creek (site 44), Red Dirt Creek (site 45), Sweetwater Creek (site 46),
Deep Creek (site 47), Grizzly Creek (site 49), and No Name Creek (site 50).
The relatively small salinity concentrations are indicative of the smal1-
solubility basalts of the White River Plateau that probably contribute most of
the base flow to these creeks.

The data for the main-stem Colorado River sites were adjusted for effects'
of reservoirs on the Blue River and the Williams Fork. The adjusted
dissolved-solids concentration was 125 mg/L at Kremmling (site 35). This
relatively small salinity is indicative of the small-solubility rocks that
underlie most of the drainage area upstream from this site. The adjusted
base-flow salt load was 41,500 ton/yr at Kremm1ing, and the base-flow
discharge was 337 ft3/s.

The adjusted dissolved-solids concentration of the Co10rado'River near
Dotsero (site 48) was 359 mg/L. The increase in dissolved-solids
concentration at this site primarily is the result of salinity contributions
from the Eagle River. The adjusted base-flow salt load was 255,000 ton/yr,
and the base-flow discharge was 722 ft3/s. Comparison with historical data
for December, January, and February of water years 1976-77 from a water-
quality station at this site indicated that measured discharge was 44 percent
lower than the average of 1,293 ft3/s, and the measured dissolved-solids
concentration was 40 percent higher than the average of 256 mg/L. The
deviation of the measured flow and dissolved-solids concentration from the
average values at the Dotsero site may be, in part, a function" of reservoir
control on flow in the Blue River.

The calculated dissolved-solids concentration in the Colorado River below
No Name Creek (site 51) was about 660 mg/L. The relatively large dissolved-
solids concentration at this site is probably caused by the flow into the
Colorado River of highly saline water from hot and warm springs between
Dotsero and Glenwood Springs. Tributaries to the Colorado River along this
reach (sites 49, 50) contained measured dissolved-solids concentrations of
less than 200 mg/L and only contributed an estimated flow of 9 ft3/s and
1,500 ton/yr of base-flow salt load to the Colorado River.

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