PROJ00259

• Contract/PO #: C153424
• Contractor Name: Colorado River Water Conservation District
• Water District: 0
• Bill Number: XB 99-999
• Loan Projects - Doc Type: Feasibility Study

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Basin. The bedrack is the lawer part .of the Wasatch Farmatian .of
Tertiary Age, which cansists .of lenticular beds .of claystane,
siltstane, sandstane and canglomer,itic sandstane. The beds dip 100
ta 150 sauthwest. They farm the southwest limb of the Divide Creek
anticline, the axis .of which is abaut 1 mile ta the northeast. Jaints
are canspicuaus in the more competent units. The most abundant jaints
are parallel ta the bedding. Secandary jaints are at right angles to
the bedding and are parallel to the strike or at right angles ta the
strike.

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The bedrack is in large part cancealed by surficial depasits.
At the damsite the surficial depasits include calluvium, debris fan
depasits, terrace depasits and alluvium. In the reservoir area, in
additian, are landslide depasits. The calluvium consists of silt,
sand and gravel derived fram the weathering .of the bedrack. Mixed
wi th the calluvium are baulders and gravel .of basalt, which were
derived from the erosion .of the terrace depasits. The debris fan
deposits were farmed by erosion .of landslide deposits in the reservair
and cansist .of angular ta subraunded baulders and gravel .of sandstane
in a silt and sand matrix (Ref. 29). Terrace depasits .occur high an
the slapes at either abutment and three levels .of terraces have been
recagnized in the reservair area. The terrace depasits cansist .of
raunded baulders, cabbIes, gravel, sand and silt derived from the
terrace depasits, the debris fans and the calluvium. The taes .of twa
landslides encraach an the reservair area. The landslides were
derived fram the Mesa Verde Farmatian, which is expased along the
crest .of the Divide Creek anticline east .of Divide Creek, and which
cansists .of beds .of massive sands tane wi th interbedded clay shale and
siltstane. The landslide depasits cansist .of angular blacks .of
sandstane, ta a yard in diameter, in a matrix .of sandstane gravel,
sand and silt. (See Figure IV-I)

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The alternate damsite, the Upper Kendig site, abaut .one half
mile abave the canflence .of Spring Creek and West Divide Creek, has
similar gealagy. The bed rack is the Wasatch Farmatian; which is in
large part cancealed by calluvium, landslide, and terrace depasits.
(See Figure IV-2)

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Materials far canstructian "f an earthfill dam .or rallercrete
dam can prabably be develaped lacall:, fram the alluvium, debris flaws,
.or landslide. The terrace depasits have nat been investigated, but
passibly cauld be saurces .of gravel and sand far cancrete and filler
material. If nat suitable, the neat'est saurce is the gravel depasits
alang the Calarada River ta the narth. Na material suitable far
riprap .or far use in a rackfill dam :Ls lacally available.

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