WSP09675

• File Number: 8041
• Description: 208 Clean Water Grant
• State: CO
• Date: 8/16/1982
• Author: CWCB
• Title: Quarterly Reports on the 208 Clean Water Grant for the Water Quality Control Division of the Coloradio Dept of Health
• Water Supply Pro - Doc Type: Publication

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3762

The Dolores River crosses two collapsed salt anticlines
which together account for a salt pickup of approximately 251,000
tons per year. Paradox and Gypsum Valleys contribute 230,000 and
21,000 tons respectively. Several small thermal springs in the
headwaters of the Dolores and San Miguel Rivers contribute a
total of 400 tons of salt annually. Although not quantified, the
report identifies drainages entering the Dolores River from the
east, between Dolores and Bedrock, as significant natural diffuse
sources of salt loading. The drainages, including Disappointment
Creek, are underlain by rocks containing readily soluble
minerals. The total salt yield by natural sources was estimated
at 347,000 tons per year.

EPA - Mineral Quality Problems

The EPA measured the salt yield for the Dolores River near
Cisco at 606,000 tons for the periOd beginning in June, 1965 and
ending in May, 1966. Close to 90 percent of that total was
traced back to natural sources. The Dolores River Basin salt
budget for the period of study is shown below.

TOTAL

TDS Load
(tons/year)

16,800

43,400
253,700
7,300
284,800
606,000

Percent of
Total Load

Source

Irrigation
Industrial effluent &
seepage from ponds
Springs and salt seeps
Mine drainage
Runoff

2.8

7.2
41.8
1.2
47.0

A mean salt load addition of 251,000 tons per year was due
to the solution of minerals from the Paradox Valley salt
anticline. A similar phenomenon was responsible for a
contribution of another 2,000 tons per year at Sinbad Valley.

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