WSPC06079

• File Number: 8064.100
• Description: Ute Tribes
• State: CO
• Basin: San Juan/Dolores
• Water Division: 7
• Date: 6/1/1987
• Author: Boyle Engineering
• Title: Agricultural Engineering Study - Mancos Watershed - Task D-E - Final Report - Design-Cost Estimate for Off-Farm Irrigation Facilities and PIA Determination
• Water Supply Pro - Doc Type: Report/Study

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150a
irrigation water requirement for a 7,200 AF reservoir and a 4,400 AF
reservoir respectively.

Reconnaissance-level layouts were made of a zoned earth embankment

dam with a cutoff trench 80 feet deep to bedrock for each size of

reservoir. Both sizes of dam were laid out with a crest width of 25

feet. Freeboards of 19 feet for the 7,200 AF reservoir and lB feet

for the 4,400 AF reservoir above their normal high water surface

elevations, resulted in crest elevations of 6,065 feet and 6,044,

respectively. Quantities were estimated for dam embankments having

3:1 and 2.5:1 upstream and downstream slopes, respectively. The

internal impervious core zone, upstream transition zone, and filter

and drain zones were assumed to have upstream and downstream slopes

of l:l and 0:5.1, respectively, sloped in the upstream direction.

Foundation preparation would consist of stripping approximately

five feet below the dam footprint, excavation of a cutoff trench to

bedrock, grouting both abutments, and constructing a grout curtain

below the core zone-rock foundation contact.

The conventional outlet works was oversized to accommodate diversion

of the river during construction. It would be located in either the

left or right abutment at as Iowan elevation as practical and would

be founded on rock. The portion of the outlet conduit passing under

the central core zone would be encased in concrete with cutoff-

collars to prevent piping along the conduit surface. The outlet

works inlet structure located in the upstream section of the outlet

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