BOARD00318

• Board Meeting Date: 11/19/2001
• Description: CF Section - Construction Fund New Loans Owl Creek Reservoir Company - Owl Creek Reservation Rehabilitation
• Board Meetings - Doc Type: Memo

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Owl Creek Reservoir Company
November 20,2001

Agenda Item 22E

directly into Owl Creek Reservoir. The Owl Creek Reservoir Company does have
sufficient water rights to fill the reservoir on an annual basis,

Proiect Description

Three design alternatives were evaluated in the feasibility study:

1. No action
2. Reconstruct existing dam embankment and construct new outlet structure and
spillway (est. cost = $800,000)
3. Reconstruct existing dam embankment, construction new outlet structure and
spillway, and dredge the reservoir to provide an additional 400 acre-feet of storage
(est. cost = $1,250,000)

Alternative No.1 was not deemed acceptable since it did not allow the storage of water,
and the ability to irrigate or exercise the existing water right. Alternatives No.2 and 3
are the same with the exception of dredging the reservoir under Alternative No.3. The
Owl Creek Reservoir Company would prefer to construct Alternative No.3 to allow
additional reservoir storage to be created upon rehabilitation of the dam.

Selected Alternative No.3 consists of leaving the existing embankment in-place and
constructing a new embankment around it. The new embankment slopes will be 6H: 1 V
on the upstream side of the dam and 3H:IV on the downstream side of the dam. A 3-foot
thick clay liner will be placed along the entire length ofthe embankment to act as a
seepage barrier, in combination with a toe drain system. A new 42-inch steel pipe outlet
pipe will be constructed with an inclined sluice gate mounted over the pipe entrance.
Based on the Class III dam classification, a new 210- ft. wide spillway will be constructed
to pass the required 100-year storm event with a maximum depth over the spillway not to
exceed 3-feet. Additionally, to generate additional storage, approximately 375,000 cubic
yards of material will be dredged from the interior of the reservoir.

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The total estimated cost of these improvements are summarized as follows;

* Engineering
* Embankment/Spillway
* Outlet Structure
* Toe Drain/Instrumentation
* Dredging
* Testing, Inspection, Surveying, Contingency

$150,000
$390,000
$100,000
$45,000
$375,000
$190.000

Total Est. Project Cost = $1,250,000

The implementation schedule for this project calls for the completion of the financing
arrangements and final design to be completed in the fall of2001 with construction to
commence in the winter/spring of2002.

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