PROJ00382

• Contract/PO #: C153685
• Contractor Name: Monument, Town of
• Contract Type: Loan
• Water District: 10
• County: El Paso
• Bill Number: SB 94-029
• Loan Projects - Doc Type: Feasibility Study

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Chapter III . Background Information

Spillway Width:

130 feet

Spillway Capacity:

11 ,400 cfs

Spillway Crest Elevation:

6918.7 feet

Outlet Works:

Twin 16-inch cast iron pipe

Outlet Capacity:

63 cfs

Several dam safety deficiencies have been noted by the SEa, which include the
following:

I. Upstream Slope: Poor condition due to the thick tree and brush cover and erosion gullies
up to 2-foot in depth.

2. Crest: Poor condition due to large trees along the crest, deep erosion gullies up to 3-foot
deep.

3. Downstream Slope: Poor condition due to large trees, brush, and deep erosion gullies.

4. Seepage: Unacceptable condition due to seepage under spillway structures.

5. Outlet Works: Poor condition due to a left gate failure and condition of the existing outlet
pipe.

6. Spillway: Poor condition due to inadequate spillway capacity, back cutting erosion at the
lower cutoff wall and the failed gabion structure along the right lower end of the spillway.

The SEO has rated the dam to be in "very poor" condition and in immediate need of

major repair. The reservoir is presently restricted three feet below the spillway crest due to the

inadequate spillway capacity and the structural condition of the spillway.

A site visit of Monument Lake Dam was performed on February 19,1999. The following
features of the dam were reviewed: upstream face of the embankment above the reservoir; dam
crest; downstream face of the embankment; left and right abutments of the embankment;
downstream toe area of the embankment; spillway and downstream channel; outlet works pipes

Monument Lake Dam Feasibility Study