C153773 Feasibility Study

• Contract/PO #: C153773
• Contractor Name: Morrison, Town of
• Contract Type: Loan
• Water District: 9
• County: Jefferson
• Bill Number: HB 95-1155
• Loan Projects - Doc Type: Feasibility Study

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It is assumed the use able service life of the existing 3,000 lineal feet of 12-inch CIP gravity line
constructed in 1961 is more than 80 years. Therefore, the pipeline should be useful for about
an additional 50 years. For purposes of developing a comparative annual cost for this
alternative, a replacement cost figure has been estimated. Replacement cost of the gravity
pipeline along the steep and narrow hillside is estimated to be $225,000. However, if Jefferson
County Open Space decides to utilize the pipe alignment for a major hiking trail, the ability to
access the pipeline with conventional small earthmoving equipment would be much improved,
and the replacement cost would be reduced considerably.

If the intake pipeline were damaged, the 29 acre-feet of operating reservoir could meet existing
water demand for one to three months without a crisis while the line is repaired. Additionally,
during such a scenario, water conservation measures could be implemented by the customers,
if necessary, during a repair period. With additional storage made available from the Cooley
Reservoir for raw water supply, the impact to the Town's municipal water supply system by
shutting down the intake system for repair over an extended period of time would be lessened.

The approximately 3,000 feet of existing gravity intake 12-inch cast iron pipeline can continue
to serve Morrison at little maintenance cost. Operation and maintenance in the past has
included repair of covering insulation, maintaining earthen cover over the pipeline, removing
sediment from the stilling basins and grit chamber, clearing debris from the headgate, and
clearing ice blockage. Although the transmission pipeline may still be in good condition,
problems such as freezing and land slides could occur which would prevent Morrison from
diverting any water. With the replacement of the upper most 800-feet of intake pipe and stilling
basin, and maintenance of insulation around the pipeline, the constant flow of water though the
pipe should minimize freezing concems.

In addition with Option B-1, a new transmission line from the water plant site to the operating
reservoir is required to replace the existing 4-inch and 6-inch steel lines.

Option B-2: Construct a New Pump Station Intake
This alternative plan is shown on Drawing III-B.

Pumping directly from Bear Creek at a point near the treatment plant to the Morrison Operating
Reservoir would require permitting from the Corps, FEMA and Division of Wildlife and new
easements. In addition, the change would involve construction of a new intake structure, check
dam, grit chamber, stilling basin, pump station and pipeline to the water treatment plant.
Adequate power would also have to be conveyed to the new site. Once the new system is

70-080.035:MSTR-PlN

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