WSP00960

• File Number: 8276.150
• Description: Grand Valley Unit-Colorado River Basin Salinity Control Project
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/1974
• Title: A Look At Salt Pick Up from Irrigated and Non-Irrigated Lands with Special Emphasis on the Effect of On-Farm Water Management Measures in Reducing Salinity of the Colorado River
• Water Supply Pro - Doc Type: Report/Study

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Introduction

Salinity has long been a major problem in the agricultural use of land in
the West and is considered the most significant water qual ity problem in
the Colorado River Basin. Salt problems are not new as ancient civiliza-
tions flourished with irrigation of fertile valley lands but dwind,ed as
silt and s~lt accumulations forced much of the land out of production.
About 3.4 million acres of land are irrigated in the Co"lorado River Basin
and nearly an irrigation farmers have to be concerned I"tith sal inity prob-
lems. Either they are concerned with maintaining a salt balance in the
root zone suitable to the crops grown or they should be concerned with the
quality of the return flows to the streams. In basins I"lhere mineral qual-
. ity of water is a problem, the users of land either affect or are affected
by the salt problem. But, like sediment salinity in water is a result of
the i nte racti on of water with soi 1 and other geo I og1 c fo rmati ons and as
such can be influenced by man's actions only to a degree. Maintaining high
standards in the use and manaqement of land and water resources is the basic
and long-range solution to the problem of increasing salt loading of stream-
flow.

The occurrence of salinity of the water of the Colorado River is wel, docu-
mented in the 1971 Environmental Protection Agency report, "The Mineral
Quality Problem in the Colorado River Basin" and in U. S. Department of the
Interior progress reports on "Quality of 14atet', Colorado River Basin." The
---Grand Valley is seen as one of the principal irrigated areas contributing
salt to the Colorado. This paper results from an examination of existing
information on sal inity in this area and further analysis of the role of
deep percolation and surface runoff from farm irrigation systems on salt
pick up. Because ~djacent upland drainage areas also contribute salts to
the Colorado River, this aspect is examined also. More reliable data and
analysis of many aspects of salt loading from irrigated areas and diffused
land sources are needed before impacts of alternative control programs can
be adequately determined.

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