WSP09790

• File Number: 8220.100.70
• Description: CRSP
• Basin: Colorado Mainstem
• Date: 3/12/1980
• Author: CWCB/WPRS
• Title: Annual Planning, Construction and Operating Projects Review, West Slope Projects, Colorado
• Water Supply Pro - Doc Type: Publication

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from Stage One would be evaluated before deciding
to proceed with construction of the rest of the
unit.

Grand V~lJ_~!].!.!:.
llarch 1980
Page 2,of 2

wells in the Reed Wash Study Area; (3) samples
and water levels from an extensive network of
wells vallcyv,idc; nnd (4) computation of water
and salt budgets for the Grand Valley and for
the Reed Hash Study Area.

Stage One development would involve the concrete
lining and rehabilitation of structures along a
6.S-mile section of the Government Highline Ca-
nal between Big Salt Hash and Hack Wnsh in the
western end of Grand Valley. Thirteen laterals
that now serve the area under the canal section
to be lined would be consolidated into 11 and
placed in pipe sections. About 6.5 miles of
interceptor ditch and four small detention ponds
would be constructed above the canal .section to
prevent runoff from entering the canal. Some
existing cross-drainage features would be en-
larged. A field station would be constructed
as part of the Stage One development for use as
a construction headquarters and permanent oper-
ating facilities for the entire unit. To com-
pensate for wildlife habitat losses, an area of
suitable land would be acquired and initially de-
veloped) and a watering pond would be construc-
ted above the Government Highline Canal.

An extensive drilling program has been completed
to obtain subsurface geological data along all of
the major canals in the valley. The core samples
obtained will yield information on the presence
and extent of expansive clays, depths to water,
and the type of sedimentary materials, all of
which will affect the engineering design of the
canals and laterals.

LOCAL INTEREST

Interest in the Grand Valley Systems Improvement
Program by Federal, State, and local concerns is
continually growing. In keeping with this interest,
the Grand Valley Salinity Coordinating Committee
meets regularly and is open to all persons and
agencies interested in attending. The purpose of
the committee is to coordinate all salinity studies
and to disseminate information to the public.

Data-gathering will continue) to determine the
nature and extent of the salt loading to the
Colorado RiVer. Such data will include the
following: (1) flow measurements and samples
from all major washes and drains; (2) samples
and water levels from existing observation

The contract between the u.s. and the Grand Valley
Water Users Association for the repayment of opera-
tion, maintcnance, and replacement costs on Stage
One is still being negotiated.

STATISTICS
(TAKEN FROM SPECIAL REPORT FOR STACE ONE)

EFFECTS O~ THE COLORADO RIVER (average annual)

PROJECT FEATURES

Decrease in salt load (tons) . . .
Reduction in depXetion (acre~feet)
Reduction in salt concentration at
Imperial Dam from decrease in
salt load (mg/L) . . . . . . . .

24,000
200

Canal to be lined (mil. 6.8
Laterals to be improved (miles)
Existing. . . . . . . 34.2
After construction. . 29.0
Detention ditch (miles). 6.5
Detention ponds (number) . . . . 4

2.5

ESTIliATED COSTS

Construction costs (October 1980)
Canal lining and improvement
Lateral improvement
Permanent operating facilities
Wildlife plan
Investieations prior to authorization
Irrigation }illnagement Services!/
Total
Interest during construction (5 years
at 5.625 percent)
Less costs of investigations prior to.
authorization
Total investment for
economic analyses
Annual equivalent costs (50 years at
5.625 pcrccnt)
Construction costs
Increased operation, maintenance,
and replacement costs
Total
Cost per mg/L of salinity reduction at
Imperial Dnm
1/ Represents monies already expended, though
program will be discontinued after 1979.

$10,150,000
10,150,000
500,000
975,000
25,000
25,000
$21,825,000

848,000
-25,000

$22,648,000

$1,362,000

10,200
$1,372,200

549,000
the .

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