PROJ00148

• Contract/PO #: C150023
• Contractor Name: Ryan Gulch Reservoir Company
• Contract Type: Loan
• Water District: 4
• County: Larimer
• Bill Number: SB 99-173
• Loan Projects - Doc Type: Feasibility Study

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of the training berm and downstream right side of the spillway, RCC will be constructed in 10-foot-
wide lifts stair step fashion, as indicated in Figure IV -4. No drainage under the spillway slab will
be required, since the dead weight of the RCC is adequate to resist the hydrostatic pressure during
the design flow.

Discharge from the spillway will be safely confined within the armored channel up to a
distance of approximately 100 feet downstream of the embankment toe before the discharge leaves
the channel and spreads out into the natural channel.

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Spillway Alternative S2 - Articulated Concrete Block with Training Walls
Spillway Alternative S2 is similar to Alternative S I with the exception that the spillway is
protected with articulated concrete blocks and a concrete training wall located along the westside
of the spillway, as indicated in Figures IV-5 through IV-7. The training wall has a height ranging
from 9 to 13 feet, and a total wall length of approximately 290 feet.

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ACB is matting of precast concrete blocks that are tied together in both directions with

cables, as shown in Figure IV-6. A woven geotextile is placed under the blocks as a filter, and the

blocks are anchored with Duckbill anchors for uplift resistance. The void spaces among the blocks

are filled with topsoil and then seeded. The established grass will provide additional erosion

resistance.

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Spillway Alternative S3 - Articulated Concrete Block with Berm
Spillway Alternative S3 is similar to Alternative S2 with the exception that a berm is used
instead of a concrete training wall, as indicated in Figures IV-8 through IV-I O. A new compacted
earthfill berm will be constructed on the right end of the existing embankment to serve as a training
berm for the spillway and to protect the toe of the embankment, as shown in Figure IV- 9. The
training berm has a crest width of 10 feet at elevation 5018.9, which matches the existing crest
elevation of the embankment. The training berm has a total length of236 feet, as shown in Figure
IV-IO.

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C.IWQRK',PROJECTS' R Y ANiFEASREPORT RYANRPT.DOC

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J:lnuary 12, 1999