C153514 Feasibility Study

• Contract/PO #: C153514
• Contractor Name: Farmers Water Development Company
• Contract Type: Loan
• Water District: 60
• County: San Miguel
• Bill Number: SB 87-15
• Loan Projects - Doc Type: Feasibility Study

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2.0

REMEDIAL PROGRAMS SCOPE AND PURPOSE

The purpose of the overall remediation program at Gurley Reservoir
is to address the dam safety issues identified by the Colorado Office of
the State Engi neer in the zero storage restri cti on 1 etter of December
15, 1986. The letter states that an acceptable repair plan must, as a
minimum, include the following items:

1. Seal i ng of all sources of 1 eakage into the condui t and valve
tower;
2. Filling of any voids which exist adjacent to the outside of
the conduit to restore the structural integrity of the outlet;
3. Repair of all areas of cavitation in the outlet;
4. Repair of the gate seats to significantly reduce leakage;
5. Replacement of the air relief system; and
6. Restoration of the integrity of the embankment and foundation
in areas where piping (internal erosion) has occurred.

The emergency repa i r (Phase 1)
Reservoir during April 1987 addressed
remediation work tasks, including:

program compl eted
the most serious

at Gurl ey
short-term

1. Grouting of voids around the outside of the outlet conduit
tunnel from the inside of the conduit using a
cement/water/sand grout mix to minimize the flow of water and
piping of soil solids into the outlet conduit;

2. Mortaring of open weepho1es, large voids and leaking joints in
the original concrete tunnel lining as an additional defense
against the inflow of water and piping of soil; and

3. Backfilling the nine existing sinkholes with cement/water/sand
grout to minimize future inflow along these flow channels and
mitigate possible loosening of the neighboring embankment and
foundation materials due to progressive sinkhole collapse.

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