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

C. Scope

This document contains general guidelines for selecting and accommodating

IOFs for the safe design of proposed dams and ensuring the safety of exist-

ing dams. In general, guidelines for proposed dams are to be applied to

existing dams. However, these guidelines recognize that special considera-

tions may sometimes be required for existing dams. The basic philosophy and

principles are described in sufficient detail to permit uniform application

and to achieve a consistent and uniform nationwide treatment among Federal

agencies in the design of dams from the standpoint of hydrologic safety. The

objective of these guidelines is to achieve a reasonable degree of uniformity

and still provide flexibility necessary to meet individual agencies' needs,

The following subjects are discussed in the guidelines:

. Flood estimation. - Estimating design floods for dams based on methods

that take into account pertinent hydrologic and meteorologic conditions.

. IOF selection. - Selection of an appropriate IOF based on an assessment

or evaluation of impacts on the areas adjacent to the reservoir, at the

dam, and downstream from the dam.

. Accommodating the IOF. - Establishing site-specific flood routing

criteria; selecting spillways and outlet works that will ensure the

integrity of the structure by safely conveying IOF flows to the natural

watercourse downstream from the dam; and determining a freeboard allow-

ance for wind setup, wave runup, and other factors.

. Existing dams. - Considerations for adapting guidelines developed f~

proposed dams for application to existing dams during periodic evalua-

tions, recognizing site-specific conditions and economic conditions that

may prev a i1 .

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