WSP01644

• File Number: 8170
• Description: Arkansas Basin Water Quality Issues
• State: CO
• Basin: Arkansas
• Date: 3/14/1997
• Author: Bradford Austin
• Title: Report to the Commissioner of Agriculture - Ground Water Monitoring Activities - Arkansas River Valley Alluvial Aquifer 1994-1995
• Water Supply Pro - Doc Type: Report/Study

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The Lower Arkansas River in Colorado, is the
most saline stream of its size in the United States.
The average salinity levels increase from
approximately '300 ppm Total Dissolved Solids
(IDS) east of Pueblo to over 4,000 ppm TDS near
the Kansas state line. The shallow alluvial wells in
the area have similar TDS concentrations. Water
containing more than 2,000 ppm TDS has often
been assumed to be unsuitable for irrigation. As a
result of these conditions, the salinity hazard of
ground water pumped for irrigation is of great
interest to the agricultural producers in the valley.

Total soluble salt content of irrigation water
generally is measured either by determining its
electrical conductivity (EC), which is reported as
micro mhos per centimeter, or by determining the
actual salt content in parts per million (ppm). The
figures on page 5 of this fact sheet show the EC
measured in ground water as you move downstream
from just east of Pueblo to the Kansas state line.
The index map below the EC graph shows the well
locations. Water with measured EC values above
1500 may have adverse effects on many crops and
requires careful management practices. Water with
EC values above 3000 can be used on salt-tolerant
crops on permeable soils with careful management
practices and only occasionally for more sensitive
crops.

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DIVISION OF PlANT INDUSTR.Y

Brad Austin
Colorado Department of Public
Health and Environment
[phone]

Mitch Yergert
Colorado Department of Agriculture
Division of Plant Industry
[phone]

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University

Reagan Waskom
Colorado State University
Cooperative Extension
[phone]

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