WSP05305

• File Number: 8449.900
• Description: Bear Creek
• State: CO
• Basin: South Platte
• Date: 7/7/1977
• Author: Wright-McLaughlin
• Title: Soils and Geologic Reconnaissance Investigation Morrison Exchange Reservoir, Jefferson County, Colorado
• Water Supply Pro - Doc Type: Publication

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pervious grave1s*, we estimate that underseepage losses could
be between 1,5 and 150 cfs for an impervious structure con-
structed without a foundation cutoff. The extend of the per-
meable materials beneath the dam, and their permeability should
be investigated during final design. The natural of the under-
lying bedrock should also be investigated.
The reservoir is within an area mapped by the Colorado Geo-
logical Survey (Special Publication 5-A) as possibly containing
sand and gravel resources. There is pi'obab1y insufficient
materials present to warrant a commercial operation, however,
this aspect should be considered during planning.

RecoTTfTlendations

Prior to final design, we suggest that a complete soil in-

vestigation be undertaken. The geotechnical data from such an

investigation should include, but no be limited to, the depth

to bedrock at the dam axis, the engineering properties of the

bedrock, the thickness of and engineering properties of the

alluvium, the nature of the man-made fill on the north abut-

ment, the types and quantity of materials with which to con-

struct the embankment, permeability of the alluvium and the

bedrock.

*Earth and Earth-Rock Dams, 1963, by Sherard-eta1, Page 269