WSP01897

• File Number: 8270.100
• Description: Colorado River Basin Water Quality/Salinity -- Misc Water Quality
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/1977
• Author: USDOI
• Title: Quality of Water - Colorado River Basin - Progress Report No. 8 - January 1977
• Water Supply Pro - Doc Type: Report/Study

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PART V. EFFECTS OF SALI~ITY ON WATER USE

Water quality can be a factor in limiting the use of a water supply.
Different water uses require waters of different qualities, and a
supply may be acceptable for some uses but unsuitable for others. Most
water uses have a range of quality within which a supply may be acceptable
for that use. Use of water at the low quality end of this range may
impose an economic, a social, and/or a political penalty on the water
user In comparison to use of the water at a higher quality. The suita-
bility of the quality of a water supply for use Is thus a relative
matter and must be evaluated with regard to specific uses and the social
and economic aspects of such use.

An important objective of salinity investigations is to assess the
suitability of Colorado River water for various beneficial uses. The
following sections discuss the physical and economic effects of salinity
on water uses in the Colorado River Basin.

A. In-stream Use

The major in-stream uses (uses where water is not depleted) of
water in the Colorado River Basin include hydroelectric power production,
propagation of fish and aquatic life, recreation (including water contact
sports), and aesthetics. Within the range of salinity concentrations
expected in the foreseeable future, salinity should have no significant
effects on these uses.

B. Irrigation Use

The major portion of the basin water supply is consumptively used
for irrigation. Any effects of water quality on this use are thus of
major importance. Crops grown in the basin differ in sensitivity to a
salt concentration in the soil root zone, with Some crops tolerating
significantly higher concentrations in the root zone than the more
sensitive crops. Also, most crops require a lower salinity concentration
in the root zone during the germinating and seedling stage than they do
later in the growing cycle. Sallnity concentrations in the root zone
are affected by the sallnity concentration of the irrigation water,
method of irrigation, irrigation efficiency, depth and concentration of
ground water. drainability and texture of the soil, weather patterns,
and other factors. If, however, all other factors remain unchanged, the
salinity concentration of the root zone will vary with the salinity con-
centration of the irrigation water. Thus an increase in the salinity
concentration of the irrigation water will decrease the productivity of
the salt-sensitive crops if its tolerance limit of salinity concentration

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