WSP00392

• File Number: 8276.150
• Description: Grand Valley Unit-Colorado River Basin Salinity Control Project
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 4/1/1992
• Title: 1991 Annual Report: Grand Valley Salinity Control Project Monitoring and Evaluation Program
• Water Supply Pro - Doc Type: Annual Report

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'.:J c. Reduction In Salt Loading: Reduction in deep percolation helps
reduce salt load to the Colorado River. Salt load reduction
estimates were made from the five surge and conventional comparison
sites discussed earlier and data provided in Table 8. The table
shows salt load contribution by each of the comparison sites and
the reduction in salt tons per acre and total tons from surge
sites.

Data from the five comparison sites indicate that there is a
reduction in deep percolation when a surge system is used. Table 8
shows that the average difference in deep percolation between the
surge and conventional sites is 4.6 acre inches per acre. As a
result, in 1991, the average salt load reduction was 1.77 tons
per acre and varied from 0.14 tons to 2.97 tons per acre. In 1990,
the deep percolation savings was higher, 10.3 inches per acre and
the average salt load reduction was 3.21 tons per acre.

By encouraging farmers to use surge irrigation, it will be possible
for the USDA to achieve its goal of 163,000 tons of salt load
reduction annually in the Grand Valley by the end of the project.

5. Recommendations: These recommendations are based on the results
obtained from seven years of monitoring studies conducted in the
Grand Valley. These recommendations are presented as a management
tool to accomplish some of the salinity control objectives.

1. Producers need to be assisted in the proper management and
operation of improved irrigation system immediately
after it is installed.

2. Proper management of individual irrigation events requires
a knowledge of improved water management techniques. This
can be accomplished best when SCS field office personnel
can regularly work with individual irrigators on a one to
one basis during the irrigation season so that producers
will apply water based on crop needs. The SCS needs to
target those farmers that manage a large number of acres
with limited man-power, and part-time and week-end
farmers.

3. Salt load reduction through IWM can only be achieved
through intensive technical assistance and education
programs on IWM techniques and crop economics tied to
water application. Demonstration projects on irrigation
scheduling would be very effective.

4. The SCS will need to follow-up on IWM design information
provided to farmers. Determine if recommended furrow

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