WSP02737

• File Number: 8276.120
• Description: Grand Valley Unit-Colorado River Basin Salinity Control Project
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 10/1/1981
• Title: Plan of Study: Grand Valley Unit Stage Two
• Water Supply Pro - Doc Type: Report/Study

~
C\1
l'o

'P"~
~" .....,. '.I'
c'l:.:::"

. --
---

o
o

CHAPTER I

INTRODUCTION

Purpose of Plan of Study

This plan of study has been prepared to outline the upcoming advance
planning investigation for Stage Two of the Grand Valley Unit of the Colorado
River Basin Salinity Control Project and involves plans for data collection
and exchange of information, plan formulation and evaluation, scheduling of
work, and input from various offices of the Bureau of Reclamation, other
agencies and the public. It also provides a plan for public involvement. The
need for the study and the work required to satisfy its :requirements is out-
lined. The conduct of the study and the methods to be elnployed are discussed,
and the legal requirements and constraints governing the effort are identified.
In short, the plan of study will document the essential elements of the
investigation.

This document will probably be amended and revised throughout the planning
process as a result of meetings, spec1al studies, reports generated, and public
involvement activities.
J} t.V'
~ ~V' ~
~ ~~urpose of the Investigation
I
,
The investigation is being conducted to identify and delineate the saline
ground-water s ste systems in the Grand Valley that are annually contrib-
uting about 80,00 tons f dissolved solids to the Colorado River and to
study and evalua S1 Ie plans to reduce or eliminate that contribution.

Irrigation practices in the Grand Valley result in heavy salt contibu-
tions to the Colorado River. The annual salt pickup results from irrigation
return flows in the valley and is attributed primarily to conveyance system
seepage and deep percolation. Through this process, salt:~ and other minerals
are dissolved from the soil and the underlying shale of the Mancos Formation
and carried in solution to the Colorado River through drains and ground-water
aquifers.

Approximately 66,000 acres of land are irrigated in the Grand Valley.
The Government Highline Canal and associated laterals and the Orchard Mesa
canals are part of the Grand Valley Project constructed by the Reclamation
Service..!.! The other canals in the valley are owned and operated by various

1/ The Reclamation Service was renamed the Bureau of Reclamation in
1923.-