WSP07412

• File Number: 8281.950
• Description: Colorado River Studies and Investigations -- Upper Colorado Comprehensive Framework Study
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 6/1/1971
• Title: Upper Colorado Region Comprehensive Framework Study - Appendix XV -- Water Quality - Pollution Control and Health Factors
• Water Supply Pro - Doc Type: Report/Study

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SUMMARY

Water of high quality is to be found at the head of
streams near the mountain divides. Degradation of the
chemical, physical and biological quality is evident as
streams progress downward, resulting from hydrologic,
geologic and man-made influences. pollu.tion problems
of virtually every form, although generally limited in
magnitude, may be found in the Region. Epidemiological data
available suggests that for potential water-borne disease,
the rate of incidence in the Region may be higher than the
national average.

Salinity

Salinity (the dissolved salt content of water) is the
most serious water quality problem in the Colorado River
Basin. Salt loading and salt concentrating effects of
consumptive use or depletion are the primary causes of
salinity increases, Salt loading principally results from
salts contributed from diffused and point sources of geo-
logic origin, and from salts carried in irrigation return
flows. '

Future dissolved solids concentrations were estimated
for 1980, 2000, and 2020. The impact of the OBE-ERS level
of development in the Region is totaled at Lees Ferry,
Arizona, where the TDS concentration; assuming no salinity
improvement program, in 2020 is projected at 820 mg/l, or
approximately 40 percent g~eater than the 1965 concentration.
The major cause of the projected salinity increase is
continued development of the Region. It includes the
additional stream depletions for irrigation, thermal-power
production and exports, and the additional salts leached
from newly irrigated lands.

Since the major effects of salinity increases on uses
in the Upper Colorado Region will be confined to limited
areas generally in the lower reaches of stream systems,
there is considerable differences of opinion, especially
among state representatives on the workgroup, regarding
the need for a salinity improvement program. A statement
setting forth the position of the states is included in the
section delineating the salinity improvement program.

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