FLOOD09481

• County: Statewide
• Community: State
• Stream Name: All
• Basin: Statewide
• Title: Practices in Detention of Urban Stormwater Runoff
• Date: 1/1/1974
• Prepared For: American Public Works Association
• Prepared By: American Public Works Association
• Floodplain - Doc Type: Educational/Technical/Reference Information

the concept of on-site detention. A 1973
conference on flood control in northeastern
Illinois attended by 550 local public officials
and engineers clearly revealed that on-site
detention of storm water is the locally
recommended method of managing runoff. It
seems likely that the use of on-site detention
will become more popular as knowledge of
the concept spreads and as design standards
and criteria for stormwater management and
studies of environmental impact become an
integral part of the planning and engineering
of stormwater management facilities.

Legislation and Administrative Needs
"On-site detention" of stormwater runoff
is a term that few legislators comprehend any
more fully than do most of their constituents.
The average citizen finds the subject
unexciting in terms of civic or political
involvement unless property under his
ownership or management is poorly drained
or subject to flooding. Consequently, few
legislators have, in past years, felt a need to
crusade for the passage of legislation that
would provide the legal basis for improving
drainage and reducing local flooding by
on-site detention of runoff.
Although flood control has not always
been a governmental responsibility in the
United States, it has been a major concern of
citizens. In recent years, as engineering and
technical data have been developed and legal,
financial, and policy determinations made,
drainage and flood control needs have caught
the attention of many legislators. Public
interest and concern has often been aroused
in the aftermath of flooding disasters in many
parts of the United States. One of the most
destructive recent storms was hurricane Agnes
which inundated large areas of several states,
particularly areas in the vicinity of Wilkes
Barre, Pennsylvania.
It would be impractical to design and
construct storm water detention facilities to
protect property from the flooding that is
associated with storms of the magnitude and
extent of Agnes. However, most rainstorms
that occur in a given area are amenable to
practical measures that can be applied to
ameliorate potential flooding damages. A first
step in this direction is for local stormwater

management agencies to study, devise and
adopt effective legislation and enforcement
programs to regulate peak stormwater runoff
flows from new land developments and from
existing land developments where
enlargements or improvements are planned.
Why Legislation? Common sense has
determined that in any drainage basin
damages are lessened and resources are
preserved if stormwater runoff rates are
reduced rather than increased. Under the
common-enemy concept, a property owner
can rid himself of stormwater by fighting it
off as best he can; however, this can cause his
neighbor downhill to suffer additional
damages. If we apply this simple case to a
multitude of property owners in an urban
drainage basin, we obtain a perspective of the
nature of urban stormwater problems. This
example helps explain why local governments
have become involved in control of
storm water runoff, although legally they do
not have to. Detaining storm water runoff on a
particular piece of ground, or within a
particular drainage basin, is now a common
way of solving the excess runoff problem, or
at least some of the problem. This technique
works and detention facilities are more
economical in many, if not most, cases than
traditional storm sewer facilities in handling
the same runoff. Therefore, the adoption of
local legislation to control runoff flow rates
becomes a matter of adopting a new
philosophy to require property owners to
handle excess stormwater, in lieu of ignoring
the problem.
Legislation, then, is necessary for several
reasons: first, to clearly delineate the
problem of handling excess runoff in urban
areas; second, to define the responsibility any
owner has, or should have, to control the flow
rate of excess runoff from his property; and
third, to provide a general solution or remedy
by means of legislative definition rather than
a multitude of lawsuits among individual
property owners.
From a public policy standpoint, it
appears that there are at least three premises
for public legislation. These are:
I. to protect the health, welfare and
safety of the public;
2. to conserve excess storm water runoff

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