WSP03260

• File Number: 8276.120.10
• Description: Grand Valley Unit-Colorado River Basin Salinity Control Project
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 9/10/1991
• Title: Final Environmental Assessment: Alternative Lining Methods for the Government Highline Canal - Grand Valley Unit
• Water Supply Pro - Doc Type: EIS

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CHAPTER I - INTRODUCTION

Purpose of Assessment

This Final Environmental Assessment (EA) addresses changes in the
Grand valley unit (Unit) of the Colorado River Basin Salinity
Control project. The purpose of this EA is to evaluate
environmental impacts that would occur with proposed changes to the
design, construction, and administration of the east end and middle
portions of the Government Highline Canal since the Final
Environmental Impact Statement (FEIS) on the Stage Two development
for the Unit was released on May 23, 1986. It is prepared in
compliance with the National Environmental Policy Act (NEPA) of
1969 (Public Law 91-190) and under current guidelines established
by the Council on Environmental Quality, the U.S. Department of the
Interior, and the Bureau of Reclamation (Reclamation). This EA is
also intended to serve environmental review requirements in
compliance with Executive Order 11988, Floodplain Management, and
Executive Order 11190, Protection of wetlands.

Location

The Unit is located along the Colorado River in Mesa County in
west-central Colorado. For the most part, the unit includes
approximately 70,000 acres of irrigated land, of which 30,000 acres
are irrigated by the Federal system, and the remainder is irrigated
by private systems. This EA specifically concerns two reaches of
the Federal Government Highline Canal which total 31 miles in
length.

The "east end" of the Government Highline Canal is referred to as
Reach 1. It is the II-mile reach extending between a point 1 mile
northeast of the town of palisade to the Indian Wash drainage near
the Grand Junction airport (see Map 1). Irrigation water for lands
above and below the canal in this reach is supplied by the private
Stubb and Price Ditch systems. Because the irrigated lands closest
to palisade are dominated by permanent crops (high value orchards)
instead of field crops, Reach I has been subdivided into a 3.6-
mile segment (Reach lA) and a 7.4-mile segment (Reach lB). The
dividing point between Reach lA and Reach lB is at 35.3 Road.

The "middle portion" of the canal is referred to as Reach 2. It is
a 20-mile reach from Indian wash to 18 Road, north of the town of
Fruita (see Map 2). Lands above the canal in Reach 2 are generally
not irrigated. Residential areas of Grand Junction and the rural
communities of the north valley are common along the upper portion
of Reach 2. The lining of Reach 2 would complete the salinity
control lining plan for the Government Highline Canal.

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