PROJ00455

• Contract/PO #: C153583
• Contractor Name: Ute Water Conservancy District
• Water District: 0
• Bill Number: XB 99-999
• Loan Projects - Doc Type: Feasibility Study

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The sandstone can be described as moderately hard, fresh to slightly weathered, buff to tan, thinly
to medium bedded, close to wide jointed and fractured medium-grained sandstone. The sandstone
can be divided into three zones based on the occurrence of fractures, joints and lithology, as
described below:

. Massive Sandstone: moderately close joints, mostly sub-horizontal bedding, this unit
is a cliff-former with near vertical faces ranging from 10 to over 50 feet in height.
Average rock blocks in the massive sandstone appear to be one to three feet on a
side with occasional rock blocks greater than 10 feet in maximum dimension. The
massive sandstone units commonly exhibit a distinctive honeycomb weathering
pattern in the nearly vertical cliff faces.

. Blocky Sandstone: Closely jointed, prominent joint directions are vertical and sub-
horizontal, weathered on altered bedding planes, 1/4 to 1/2 inch thick. Bedding
planes suggest alternate zones of less resistant sandstone evidenced by an irregular
weathering profile. This unit has typical rock blocks from two to six inches in
maximum dimension.

. Shaley Sandstone: Moderately hard to hard, slightly fissile and weathered in cliff
faces, boulders tend to disintegrate into platy fragments of one to three inch
maximum dimension.

The sandstone is interbedded with shale. This shale can be described as medium hard, fresh to
slightly weathered, bluish dark gray, very fine grained, very thinly bedded, slightly fissile, very closely
jointed, with very thin partings.

4.4 Groundwater

The groundwater conditions in the project area can be characterized generally by a shallow water
table in the alluvial deposits and a deep to non-existent water table in areas with higher topographic
elevations.

Groundwater in the vicinity of the proposed tunnel is anticipated to be non-existent. Due to the
extreme topographic relief and the arid climate it is not anticipated that significant groundwater
would be encountered at the proposed tunnel elevation. Relatively small, discontinuous zones of
perched water may exist above individual shale units; however, the potential volume and extent of
this perched water is expected to be minimal.

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