FLOOD10053

• County: Statewide
• Community: State of Colorado
• Basin: Statewide
• Title: A Study to Identify Attitudes and Problems with Integrating Floodplain Management and Dam Safety
• Date: 8/1/1984
• Prepared For: University of Denver
• Prepared By: Stephen A. Spann
• Floodplain - Doc Type: Educational/Technical/Reference Information

,

9

have exceeded fifty percent of the PMP estimates. In fact, on

30 and 31 May 1935, a rainstorm event occured over the Cherry

Creek drainage near Denver,

Colorado,

which

approached

eighty-nine percent

of the PMP.' This value is also plotted

,.

on Figure 1 and

has a reoccurance

interval

approximately

equal to lXlO'. years.

While most individuals view the lOO-year flood as a

flood which can only happen everyone hundred years, thE term

IS acutally a misnomer which was started to help the average

citizen understand the concept.

The

lOO-year

flood

IS a

common term for the flood which has a one percent probability

of being equaled or exceeded once during anyone year.

The author has had several occasions to discuss the

issues of

dam safety and the problems of development below

dams with several county planners and program managers. While

it is recognized as a social and economic

problem not

only

for

the dam owner, but

also for the people who have their

lives and investment at risk,

it appears that

the national

programs and

judicial system have held that any restriction

to development of flood zones above the

IOO-year floodplain

is an unconstitutional taking of property rights.

Further discussion of this topic is covered

in

the

following section.

'National Research Council, Safety of Existino Dams.
Evaluation and Improvement, (Washington, D.C.: National
Academy Press, 1983), pp. 123-128.