FLOOD00787

• County: Denver
• Community: All
• Stream Name: All
• Title: Floodplain Management Tools for Alluvial Fans
• Date: 11/1/1981
• Prepared For: State of Colorado
• Prepared By: FEMA
• Floodplain - Doc Type: Educational/Technical/Reference Information

. moderate density housing across much of the

fan surface and

. moderate to high density subdivisions

located in areas protected from flooding

plus open space reserved for floodways.

Under the former scenario. local levees.

channels. and enlarged streets could be used to

safely convey flood flows. The use of

structure floodproofing is also possible. but

the cost of floodproofing many structures. the

aesthetic problems of such measures. and the

flood damages to landscaping and utilities may

be substantial. Under the reserved floodway

scenario. as shown in figure 5.2. local levees

are used to direct flood flows into open space

and to confine the flood as it moves down the

fan. No d~velopment of the floodway would be

allowed. but full development could' occur in

the protected areas. flood damages to

landscaping. streets. and utilities would be

minimal. Because much of the floodway is

natural. maintenance costs would be limited to

levee repairs and landscape work.

3. liinh density develooment can be safely

accomodated on fans through the use of whole

fan management tools. as illustrated in figure

5.3. The structural tools could be designed to

reduce the peak water and sediment discharges.

contain the flood in armored channels. and

convey flows to the fan toe. Nearly all of the

fan surface is made available for develop~ent.

Should an extreme flood event (greater than the

100 year flood) occur. eKtensive damage can be

eKpected. Local management tools such as

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