PROJ00414

• Contract/PO #: C153326
• Contractor Name: Fruitland Mesa Water Conservancy District
• Contract Type: Grant
• Water District: 0
• County: Montrose
• Bill Number: XB 99-999
• Loan Projects - Doc Type: Feasibility Study

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Suitability for Earthfill

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The borrow soils tested appear suitable for use in enlarging the

existing dam and dike. Strength and stress-strain characteristics of

the laboratory prepared and tested samples are good. Peak-stress

ratios, the ratio of major to minor principal stress, were attained at

strains on the order of 10 percent. This indicates that soils com-

pacted in a comparable manner to the laboratory procedure will behave

as a ductile material. This means that gradual deformation of the

soil mass underload will take place rather than a sudden deformation.

Also, permeability of the materials as compacted are less than 10-7

em/see as indicated by the average of two tests. Dispersiveness of

the clay materials is not indicated to be a problem.

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Borrow area quantity estimates by isopach maps indicate that about
934,000 cubic yards are available from Borrow Area A and about 350,000
cubic yards from Borrow Area B. The total of 1,300,000 cubic yards of
available borrow materials is well in excess of the approximately
225,000 cubic yard volume required for both embankments.

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No suitable filter material or riprap borrow material sources were
encountered in the two borrow areas investigated. However, there are
two potential sources for granular materials in the site vicinity.
Approximately 8 miles northeast of the site, there is a volcanic rock
quarry located on land owned by the Bureau of Land Management. This
rock could be used as riprap and crushed for aggregate or filters.
The Dakota Sandstone outcropping above the right abutment of the main
dam also appears suitable for quarrying. This may be accomplished
either between the main dam and dike or just downstream of the main
dam in Iron Creek Canyon.

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