WSP09985

• File Number: 8210.470
• Description: Pacific Southwest Interagency Committee
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 3/2/1971
• Author: PSIAC
• Title: Quarterly Reports - 71-1 through 71-4
• Water Supply Pro - Doc Type: Report/Study

JJZ228

.

.

PACIFIC SOUTHWEST INTER-AGENCY COMMITTEE
Quarterly Report for Colorado
71-4 Meeting

v'

Construction and preconstruction Activities

Bids for the diversion tunnel for the Crystal Dam of the Curecanti Project near
Gunnison, Colorado, are to be opened November 23, 1971. Specifications for the prime
contract for the concrete dam are scheduled for issuance in January, 1973. This
proposed concrete dam is in lieu of the earth dam which was bid at approximately
$5 million over the engineer's estimate. It is hoped that considerable money will be
saved by the switch to concrete.

.

Advance Planning

Recently completed analyses comparing alternative locations for Ridgway Dam of the
Dallas Creek Project near Montrose, Colorado, indicate that a dam site about 5 miles
downstream would be economically competitive with the previously selected site. The
lower site has a much more favorable foundation condition and should be environmentally
more acceptable in that it would not inundate the town of Ridgway and would create a
deeper reservoir with a smaller surface area inundating less irrigable lands and a
smaller drawdown area. Major factors that have reduced the economic attractiveness of
the previously selected site include: (1) recent drilling that indicated the morainal
material was more pervious than previously estimated and would require extensive
treatment to prevent excessive seepage losses; (2) a law passed in the last session of
Congress that requires more liberal payments for rights-of-way. Some additional work
will be required to prove the lower site but no serious problems are anticipated.

Reconnaissance Investigations

Calculations are being made to estimate the decrease in salinity that would result
from lining all of the existing project canals and laterals of the existing Uncompahgre
Project near Montrose, Colorado. A second study is being made of salinity reduction
from lining only selected reaches.

Considerable effort has been concentrated on the determination and location of possible
bottlenecks in the existing distribution system.

Colorado State Water Plan

A field draft of supporting information for Phase I (Appraisal of Present Conditions)
has been assembled. This information will now be edited and will serve as appendices
to the summary report.

The summary report for Phase I is being prepared and is now programmed for completion
on April 15, 1972.

CWCB/LDM/tam - 11/15/71

i ~