WSP05534

• File Number: 8273.600
• Description: Colorado River Basin Salinity Control - Federal Agencies - USDA
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 4/1/1994
• Author: USDA
• Title: Monitoring and Evaluation Report for the McElmo Creek Unit of the Colorado River Basin Salinity Control Program - 1993 Annual Report
• Water Supply Pro - Doc Type: Annual Report

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b. Reduction in salt Loading

Because salt load reduction is not directly. measurable it
becomes necessary to evaluate reduction in deep percolation
during field irrigation and to evaluate reduction in seepage
from existing earth ditches replaced by pipeline or ditch
lining. For each acre-foot. of water that is saved from deep
percolat.ion in the McElmo Cre.ek Salinity Project~ 4.2 tons
of salt is saved from entering the Colorado River.
Therefore, these evaluations are needed in order to achieve
this objective.

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4. Analysis of Water Quality Data

Stream gauging data was collected by the M&E Team personnel
for the 1993 irrigation season. This data was collected for
the purpose of providing information for a report written by
Mahdi M. AI-Kaisi of the Colorado state University-
Cooperative Extension Service assigned to the McElmo Creek
Salinity Office in Cortez, CO. The United States Geological
Survey (USGS) is responsible for collecting stream data. In
future reports, USGS data on.flows and TDS will be provided.

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The M&E Team members collected water samples once a month
from middle of May to the middle of September. There were
14 water samples collected along a route that extended from
the headwaters of the Dolores River to a. point 15 miles down
McElmo canyon that is. below all the irrigation tailwater
that runs into McElmo'Creek. The average TDS in parts per
million (PPM) ranged from a. low of 88 PPM at the headwaters
of the Dolores River to. a high of 1126 PPM at the last point
in McElmo canyon. McElmo Creek had an average high of 3200
PPM at a point above the influence of the irrigation
tailwater. The flow rate was not measured at any of the
sampling points so the actual salt loading factor could not
be calculated. .

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5. Recommendations

These recommendations are based on the results obtained from
four years of observing irrigation practices and monitoring
studies conducted in the McElmo Creek Project Area. These
recommendations are presented as a management tool to
accomplish some of the salinity control objectives for the
McElmo Creek Salinity Unit.

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

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