FLOOD09597

• County: Gunnison
• Community: Marble Area
• Basin: Gunnison
• Title: Engineering Geologic Factors of the Marble Area
• Date: 6/1/1972
• Prepared For: Gunnison County
• Prepared By: Colorado Geological Survey
• Floodplain - Doc Type: Educational/Technical/Reference Information

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are technically feasibi~' 'may well be unacceptable in terms of economics

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and/or environmental impacts.

'Problems Related. to" Mudf10w Control and Construction on Mudf10w Debris

General

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'" Th~re are se~er~l problems that we would anticipate in ,achieving
ec~~~~i~~l andEmvir~~entally acceptable control for mudtloi.s in the

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Marble area, and still others' relatedtb 'safe and feasib1e:aevelopment

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of the area after the mudflow'problems are solved.

Recognition of the' recent g~oibgi~ history and probable future

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course of natural events on the entire mudflow fan is basic to solution

of the many. problems related to possible defensive or control measures.

Data of this report shows that Slate Creek has in historic and very

recent times occupied a dozen or more temporary channels between the

town of Marble and its present course, and accompanying mudflows have'

spread out over an area of 200 acres or more. Since all of this area

is potentially within the reach of the Slate Creek mudflows, it is not

developable ~nti1a workable, economi~a1,and acceptable solution to

the mud flooding problem is deVised and implemented.

It ,should also be recognized that the area is composed almost

entirely of old mudflow debris which can in all probability be remo-

bi1ized by addition of water - whether from rainfall, snowmelt, lawn

irrigation, septic tank effluent, sewer line leaks, or other sources.

In laboratory experiments, debris from the Wrightwood, California mud-

flows flowed readily on a 7 degree slope (approximately 12.5% slope)

when mixed with 16% by weight of water (Sharp and Nobles, 1953, p. 552).