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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constructed, the existing gravity line could be abandoned. This option would provide a reliable
system once constructed, although pump impellers and seals would need periodic maintenance.

A recent engineering study by WRC('9, 20) investigated several possible sites for a relocated
diversion, and recommended the least costly location. The likely location for such a new intake
is on property owned by the Denver Mountain Parks. This provides a site easily accessible and
nearest the existing treatment plant and operating reservoir. Assuming the required permits
could be obtained, a new diversion dam, intake, grit chamber and wet well/pump station would
be constructed near the creek. It is assumed the pump station would be located at elevation
5,850 feet. A 1,740 lineal foot 12-inch ductile iron pipeline would be constructed from the pump
station to the treatment plant. The total capital cost of a new pumped intake was projected to
be $672,000, according to the WRC report.

Pump operating costs are based upon a static head of 105 feet (intake elevation 5850 feet to
the operating reservoir at elevation 5955 feet). Maximum flow rate capacity is based upon 4.45
cfs. Average annual pumping costs are calculated to be $14,500 at full build-out with 1,475 EQR
and municipal demand of 824 acre-feet annually, plus 62 acre-feet make-up water for
evaporation and seepage from the reservoirs.

As with Option 1, a new raw water line between the treatment plant site and the operating

reservoir will be required.

Pipeline from the Treatment Plant to the Operating Reservoir
At present, water flows by gravity from the intake to the treatment plant where the pressure is
reduced to atmospheric pressure. Water is used by the plant, pumped to the operating reservoir
or overflows back into the creek. Existing conditions require pumping between the treatment
plant and the Morrison Operating Reservoir through two-way 4 and 6-inch steel pipes.

The Morrison Operating Reservoir should be the principal control center for the raw water supply
system. Raw water would feed directly to a lower treatment plant, or into the operating reservoir
for later use in the treatment plant, or pumping up to Cooley Reservoir. The existing connection
of the treatment plant to the operating reservoir is approximately 1,000 lineal feet of 6-inch and
1,000 feet of 4-inch steel pipe. According to past reports and statements from the operators,
these lines are severely corroded and have limited capacity (about 200 gpm). Regardless of the
intake option selected, these pipelines from the treatment plant to the operating reservoir should
be replaced with 2,000 lineal feet of new 14-inch ductile iron pipe. Eliminating the overflow and
pressure dissipation at the treatment plant would allow water to flow by gravity into the Morrison

70.0SO.035:MSTR-PLN

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