PROJ00345

• Contract/PO #: C153330
• Contractor Name: Upper Yampa Water Conservancy District
• Contract Type: Loan
• Water District: 0
• County: Routt
• Bill Number: SB 77-35
• Loan Projects - Doc Type: Feasibility Study

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Specification
Page or Draw-
ing No.

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P. 147 cont.

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Dwg. 2

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Dwg. 2

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Dwg. 2

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Dwg. 2

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than 12" in size is reconnnended. This is a matter of main-

tenance rather than safety, however, and a trade-off between

lower first cost and higher maintenance may be justified.

Collector and header piping is shown surrounded by gravel

filter material. This conflicts with 'the graded bedding

material specified on page 170. It appears that the l~ inch

minus graded bedding material should extend entirely around

the pipes for a minimum thickness to provide protection against

damage.

Core (Zone 1) apparently stops at normal storage level. Zone 2

material must be relatively impervious in the crest area to con-

trol seepage when the spillway is flowing. Cambering the top

of Zone 1 to keep it above the spillway crest elevation is

reconnnended,

The maximum flood level is shown at nominal crest El. 9589.

If the inflow design flood was determined in accordance with

Bureau of Reclamation' procedure, it woul~ appear that the dam

crest elevation should provide'approximately three feet of

freeboard with the design flood, not counting camber.

The stability of the 1-3/4:1 downstream slope' ,of the dam is

presumably dependent upon the positive draining function of

the selected filter material. To insure its performance as a

chimney drain, the width should be a minimum 3 feet wide to

allow for the side slopes of each lift.