WSP05106

• File Number: 8276.150
• Description: Grand Valley Unit-Colorado River Basin Salinity Control Project
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 12/1/1977
• Title: Final Report of the Grand Valley Salinity Study - On-Farm Program for Salinity Control
• Water Supply Pro - Doc Type: Report/Study

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INTRODUCTION

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This section presents the study objectives and discusses general sa! inity
problems of the Colorado River before dealing specifically with the
problem of salt loading attributed to the Grand Valley. The authority
for USDA participation in the study and a discussion of coordination
between agencies participating in salinity studies in the valley are
identified in this section.

STUDY OBJECT! VES

The overall objectives of the U. S. Department of Agriculture's parti-
cipation in the salinity control studies in Grand Valley are to:
(1) determine the contribution of salt loading from the irrigated and
related upland areas, and (2) determine the opportunity for reducing
salt loading through improvements on irrigated farms and reducing
erosion and sediment delivery from the privately owned upland areas.

USDA activities include determining the contribution of salt, sediment,
and water into and through the irrigated area from the privately owned
upland watershed (diffuse area); and also focused on evaluating the
present condition of on-farm irrigation systems and management practices
to determine what could be done to improve present conditions and
practices to reduce salt loading. These activities were directed toward
finding answers to three questions:

1. What is the magnitude of on-farm improvement needs? On-farm
irrigation improvements include ditch lining or pipelines with
appropriate water control structures, on-farm water measuring
devices, land level ing, field drains and improved irrigation
management. Revegetation of rangeland and control of grazing
livestock will be needed to reduce runoff that contributes to
erosion of salt laden soils.

2. What are the total installation costs and annual levels of
funding required for program implementation?

3. What will be the effect on sal inity contributions to the
Colorado River? Beneficial effects will be achieved through
reducing tailwater runoff, deep percolation, and ditch seepage
from irrigation with an increase in irrigation efficiency, and
from reducing runoff and erosion from the upland watershed.
Reduced return flow to the Colorado River is translated into
expected reduction in salt loading.

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