WSP02017

• File Number: 8270.100
• Description: Colorado River Basin Water Quality/Salinity -- Misc Water Quality
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 9/1/1994
• Title: Lower Gunnison Basin Unit East Side Laterals - Colorado River Water Quality Improvement Program - SUPPLEMENT TO FEASIBILITY REPORT
• Water Supply Pro - Doc Type: Report/Study

Chapter 1 - Introduction

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The unit area referred to in this report is that portion which is within the
Uncompahgre River Valley and, specifically, the area served by the
Uncompahgre Project, a Federal development constructed in the early
1900's for irrigation of approximately 86,000 acres.

The Uncompahgre Valley was fonned by the Uncompahgre River, a
tributary of the Gunnison River, which in turn is a tributary of the Colorado
River at Grand Junction. The Uncompahgre River flows north from its
origin in the San Juan Mountains in southwestern Colorado to its
confluence with the Gunnison River at Delta.

A significant portion of the irrigation water for the Uncompahgre Project is
provided by Gunnison River flows and by storage releases from Taylor Park
Reservoir, located on the Taylor River about 70 miles east of the unit area.
Physical storage of this water may occur in either Taylor Park Reservoir or
Blue Mesa Reservoir, a feature ofthe Wayne N. Aspinall Storage Unit', as
provided by the 1975 Taylor Park Reservoir Operation and Storage
Exchange Agreement. Additional water is obtained within the unit area
from diversions of natural flows of the Uncompahgre River, its tributary
streams, and return flows as well as storage releases from the Dallas Creek
Project.

About 15 miles east of Montrose, water is' diverted from the Gunnison River
by the Gunnison Diversion Dam into the 5.8-mile-Iong Gunnison Tunnel
and flows directly into the South Canal. The South Canal has an initial
capacity of 1,060 cubic feet per second (cfs) and extends southwesterly for
11.4 miles from the end of the tunnel to the Uncompahgre River. The canal
is partially lined with concrete and includes five short tunnels along its
length. Although most of the water is released from the South Canal into
the Uncompahgre River for rediversion, some water is conveyed by a flume
across the river to the West Canal, which is about 21.4 miles long and has
an initial capacity of 175 cfs.

The West and South Canals were constructed as part of the Uncompahgre
Project. Within the unit area, six other diversion dams and canal systems
were constructed as private developments and were purchased by the
Federal Government, then improved as part of the project. They are the
East, Garnet, Ironstone, Loutzenhizer, Montrose and Delta (M&D), and
Selig Canals.

Most of the Uncompahgre Project's irrigated acreage is located on stream
terrace alluvium andlor soils fonned on and from the Dakota Sandstone
Fonnation which has a relatively low salt content. However, about
34 percent of the irrigated area consists of soils formed on and from the

, Wayne N. Aspinall Storage Unit, one of four major storage units of the Colorado River
Storage Project, provides water storage and hydroelectric power generation along 40 miles of
the Gunnison River.

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