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

(1) regulation requirements to meet project purposes; (2) the need to

impose a maximum regulated release rate to prevent flooding or erosion

of downstre!m areas and control rate of drawdown; (3) the need to

provide a minimum regulated release capacity to recover flood control

storage for use in regulating subsequent floods; and (4) to evacuate

the reservoir in emergencies and for performing inspection, mainte-

nance, and repair.

Spillways, outlet works, and penstocks for powerplants are sized to

satisfy project requirements and must be operated in accordance with

specified regulating instructions when the reservoir is within the

allocated storage levels. These facilities could be relied upon to

make flood releases subject to the following limitations:

.' Only those release facil ities which can be expected to operate

reliably under the assumed flood condition should be assumed to be

operational for flood routing. Reliability depends upon structural

competence and availability for use. Availability of a source of

auxiliary power for gate operation, accessibility of controls,

design limits on operating head, reliability of access roads, and

availability of operating personnel at the site during flood

events are factors to be considered in determining whether to

assume release facilities are operational.

. A positive way of making releases to the natural watercourse by

use of a bypass or wasteway must be available if canal outlets are

to be considered available for making flood releases.

. A specific evaluation of expected flood conditions should be

made before penstocks for powerplants are considered available for

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