PROJ00455

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

I
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I

pipeline on the west side. Costs were based on an approximate tunnel length of 3050 feet. The
major difference between alternatives I and III is that the pipe for alternative III is backfilled with
soil for stability and protection, whereas the pipe for alternative I is supported on pipe cradles or
supports. The granular backfill surrounding the pipe in alternative III will have a greater degree of
protection from freezing conditions and other environmental effects. To account for these
conditions, weatherproof doors have been added to the cost of alternative I, and it has been
assumed conservatively that the pipe will be coated every 2 years. Alternative I has the advantage
that the pipe can be inspected routinely, whereas alternative III is buried and cannot be visually
inspected.

Excavation of the tunnel is expected to require approximately 8 months. The backfill and steel pipe
for alternatives I and III could be installed in approximately 1 to 2 months whereas the concrete
pipe would likely require 2 to 3 months for installation. Excavation of the tunnel will have to be
completed before construction of the pipeline can begin. Therefore, the minimum construction
time is expected to be 9 to 12 months without a winter shutdown.

The cost comparisons were based on the following facts:

Tunnel Excavation - The tunnel for all alternatives was assumed to be eight feet high and
seven feet wide. These dimensions correspond to convenient dimensions for tunnel
excavation and a practical work area. Costs for tunnel excavation are based on estimates
from similar construction by contractors in Colorado and for excavation in good dry ground.

Steel Pipe - All steel pipe was assumed to be capable of withstanding a pressure head of at
least 200 feet of water (87 psi). The steel pipe can have either push-on joints with o-rings,
or welded joints. Material costs for the pipe do not vary significantly for the two types of
joints. However, the welded pipe is expected to be more expensive to install in the tunnel.
Costs are based on welded connections for the steel pipe.

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