FLOOD06619

• County: Statewide
• Community: State of Colorado
• Basin: Statewide
• Title: Federal Guidelines for Selecting and Accommodating Inflow Design Floods for Dams
• Date: 2/1/1986
• Prepared For: State of Colorado
• Prepared By: FEMA
• Floodplain - Doc Type: Project

define flood probabilities for rare events, and to accurately assess the

potential loss of life and economic impact of failure when it would occur,

dictate use of procedures which provide some latitude to meet site-specific

conditions in selecting the IDF.

The PMF should be adopted as the IDF in those situations where consequences

attributable to dam failure from overtopping are unacceptable. The deter-

mination of unacceptability exists when the area affected is evaluated and

factors in section F.1.c. indicate loss of human life, extensive property

and environmental damage, or serious social impact may be expected as a

result of dam failure (see qualification in following subparagraphs).

A flood less than the PMF may be adopted as the IDF in those situations

where the consequences of dam failure are acceptable. Acceptable conse-

quences exist when evaluation of the area affected and factors in section

F.1.c. show one of the following conditions:

. There are no permanent human habitations, or commercial or industrial

development, nor are such habitations. or commercial or industrial

developments projected to occur within the potential hazard area in

the foreseeab 1 e future and trans i ent popu 1 aHon is not expected to be

affected.

. There are only a few permanent human habitations within the potential

hazard area that would be i"",acted by failure of the dam and there

would be no significant increase in the hazard resulting from the

occurrence of floods larger than the proposed IOF up to the PMF. An

example is where impoundment storage is small and failure would not

add appreciable volume to the outflow hydrograph, and, consequently,

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