WSP09038

• File Number: 8276.856
• Description: Salinity Control Inventory Lower Gunnison Basin - Colorado River Salinity Control Program
• State: CO
• Basin: Colorado Mainstem
• Water Division: 4
• Date: 3/1/1976
• Title: On-Farm Salinity Control Investigation and Plan of Work
• Water Supply Pro - Doc Type: Report/Study

14

V, OBJECTIVES, SCOPE AND PRINCIPAL F~ATURES OF STUDY

Broad Objectives of On-Farm Sal in_~tYS.ontrol Investigations

The overall objectives of the U.S. Department of Agriculture participa-
tion in sa] inity control studies in the Upper Colorado River Basin are
to determine: (1) the contribution of salt loading from ,he irrigatc,J
and related privately owned upland "atershed area; (2) the opportunit'{
for reducing salt loading through improving on-farm irrigation; and (J)
the possibility'of reducing erosion and sediment del Ivery from irrig3'E~
and upland areas.

USDA Program for the Lower Gunnison Basin Unit

Major Elements of the Survey

Additional data and analyses of salt loading sources in irrigated and
watershed areas are needed before impacts of alternative improvement
programs can be evaluated. Major elements of the survey will include
updating of the preliminary water and salt budgets, determining irrigation
system and management improvement alternatives, estimating treatment
opportunities in upstream watershed areas, estimating costs and effects
of alternative treatment practices, and developing a program for imple-
menting the needed improvements. This effort will be concentrated in
the high salt source areas of the Lower Uncompahgre and the Surface and
Currant Creeks reach of the Gunnison River near Delta.

Water and Salt Budgets

A water budget will be prepared to show an overview of the inflow-
outflow ~ater pattern for the Lower Gunnison Unit and for each irrigation
system. Present and improved irrigation system alternatives will be
evaluated. Components to be determined will include diversions, canal
seepage and spill, farm del ivery, crop consumptive use, surface and
subsurface return flow, and incidental consumptive uses.

The prel iminary salt budget for the Lower Gunnison Basin Unit will be
refined to reflect additional data collected during the study period.
The interrelationships between surface water distribution, on-farm
irrigation efficiency, ditch and canal seepage, deep percolation and
other components as they relate to salt pickup will be identified,

Irrigation System and Improvement Needs

003063

The evaluation of irrigation system improvement needs will initially
concentrate on the Lower Uncompahgre Subbasin area in coordination with
the USBR Uncompahgre Project Improvement Program scheduled for completion