PROJ00026

• Contract/PO #: C153412
• Contractor Name: Louisville, City of
• Contract Type: Loan
• Water District: 6
• County: Boulder
• Bill Number: HB 83-1102
• Loan Projects - Doc Type: Feasibility Study

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The extension of the upstream cutoff key to bedrock will require
substantial excavation within the reservoir increasing the storage capacity
by 133 acre-feet. The storage capacity would be increased from the
existing 172 acre-feet to a total of 305 acre-feet.
The existing toe drain will be abandoned and a new drain system will be
installed along the full length of the downstream embankment. All water intercepted
by the system will be conveyed to the headworks (i.e., the sedimentation basin)
of the Louisville Water Treatment Plant for domestic use.
This project will require that the existing reservoir be completely dewatered
for a probable six to eight month period. If additional raw water storage is
not constructed adjacent to the treatment plant prior to the reservoir renovation,
the City's only source of raw water would be the direct pipeline from Eldorado
Springs.

The present reservoir does not have an emergency spillway which, due
to the varying crest elevations, causes spillage at various locations when
overtopping occurs. This has happened in the past by running the influent
ditch too long or having the reservoir full when a major storm is intercepted.
This occasional overtopping has caused extensive erosion damage to the adjacent
treatment plant site, the recycling pond, its spillway, the Davidson Ditch, and
creates the potential for a major embankment failure. It should also be noted
that the State Engineer will require an adequate spillway prior to approving
the project. The proposed emergency overflow spillway would be 5 feet deep and
7 feet wide.
2. Gravel Pit Alternate - This site would provide approximately 99 acre-feet
of water storage with a depth of about 9 feet when filled to the normal high water

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