WSP02105

• File Number: 8200.765
• Description: White River General
• State: CO
• Basin: Yampa/White
• Water Division: 6
• Date: 5/1/1986
• Author: Morrison-Knudsen
• Title: White River Geotechnical Study - Final Report - Volume I
• Water Supply Pro - Doc Type: Report/Study

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Adequate construction materials are located within close proximity for either
an embankment or RCC dam. Alluvial sand and gravel for use as shell material
in an embankment dam or for RCC aggregate is available in the river valley and
in terraces along the right side of the reservoir. Impervious core material
for an embankment design is available less than one mile north of the site.

The slopes of the reservoir created by a dam at Warner Point are considered to
be stabl e, although further studies and surface instrumentation is indicated
on the left side of the reservoir upstream of Elk Creek. The biggest question
regardi ng the Warner Poi nt Proj ect is the si gni fi cance of outcrops of the
evapori ti c faci es of the Eagl e Vall ey-Mi nturn Fonnati on withi n the reservoi r.
This aspect of project feasibility should be the subject of future, more
detailed studies. It is felt that the evaporitic deposits are irregular,
discontinuous layers; and it is, therefore, unlikely that a single bed occurs
that woul d connect outcrops wi thi n the reservoi r wi th a dayl i ght poi nt more
than five miles downstream.

The estimates show that except for the 50,000 acre-foot reservoir, the cost of
an embankment dam is about equivalent to the RCC gravity dam design. The
50,000 acre-foot RCC dam is 25 percent less expensive than the embankment dam
at a similar size because of the additional costs associated with constructing
the spillway on the left abutment. This differential might disappear,
however, if the centerline were shifted a short distance downstream to a more
favorable alignment for the smaller size dam.

The Warner Point Dam compares very favorably from the economic standpoint with
the other projects studied on the White River. It ranks as the least expensive
site for the 50,000 acre-foot and 150,000 acre-foot storage capacities and
second to the Powell Park Dam for the 300,000 acre-foot reservoir.

Choke Cherry Dam
After initial drilling at the Warner Point site indicated the stream-bed
alluvium to be from SO to 75 feet thick, overlying bedrock, it was hoped that
the Choke Cherry al i gnment woul d provi de a more favorabl e result. The only
hole drilled, however, revealed the gravel to be at least as deep as at Warner
Point.

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