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

example, the land is expected to cost about
$1 .8 million which represents about 72
percent, or more, of the total project cost of
$2.1 to $2.5 million.
The Metropolitan Sanitary District of
Greater Chicago has estimated the overall
initial costs of large storm water detention
basins, constructed by them on land
purchased by the District, at ab9ut $5,500
per acre-foot of storage. This is a rough
estimate and the cost will vary with the
circumstances, the project location, and unit
cost factors.
In a large single-family residential
development in Hoffman Estates, lllinois the
cost of providing detention ponds and basins
in open-space areas was estimated by the
developer to cost between $100 to $300 per
lot, with lot sizes varying up to 1/2 acre. It is
believed that the overall costs of the drainage
system serving this development was much
less than the cost of a conventional storm
sewer system without provision for detention.
This probably resulted in lowering the sales
prices of the houses below that which would
have otherwise been charged. As an added
feature in offsetting costs, the detention
ponds serve recreational uses and enhance the
aesthetics of the area. ·
Sedimentation control ponds used during
the construction of homes in Maryland have
cost about $50-$70 per lot. Although these
ponds are built to reduce and prevent soil
erosion and the accompanying siltation, they
would also serve to reduce local flooding and
pollution if left as a part of the final
development.
At times, arrangeme1).ts are made with
land developers to have land (or a constructed
facility) donated to a public agency for
stormwater detention. In this way, the cost of
detention storage to the public agency is
sometimes greatly reduced over that cost
which would be incurred if the public agency
provided the land and constructed the
facility. In addition, the owners of properties
served are relieved of the burden and cost of
operation and maintenance of such facilities.
However, in instances where the land
developer pays the original capital costs
associated with on-site detention, the actual
costs are necessarily transferred to the

ultimate owner of each tract or lot. If the
on-site detention basin has to withhold
significant flows from upstream areas, this
imposes inequitable costs on the ultimate
owners of the properties undergoing
development.
increased costs there are reduced costs
associated with on-site detention of
storm water. The use of rooftop storage of
rainfall will reduce the size of roof drainage
pipes needed; all types of storm water
detention will reduce the size of sewers
needed, etc. These factors are discussed more
thoroughly in this chapter, and in Chapter 4.

Financing: The financing of stormwater
detention facilities is a difficult and important
matter that deserves careful consideration.
Financing may be provided by many different
methods each having variations in the manner
of cost allocation. Some possible methods of
financing are listed below:
1. Federal aid:
a. Department of Housing and Urban
Development funds
(1) Open-space programs
(2) Water and Sewer Facilities
program s
b. Soil Conservation Service watershed
project funds
c. Corps of Engineers flood control
projects
d. National Park Service Land and
Water Conservation funds
e. Department of Interior - Bureau of
Outdoor Recreation programs;
2. state flood control funds, and park funds;
3. drainage district funds;
4. sanitary district funds;
5. county forest preserve district funds;
6. general obligation bonds;
7. general improvement bonds;
8. special improvement bonds;
9. drainage assessments based .on one, or a
combination, of the following:
a. property value
b. property size
c. amount of runoff contributed
d. linear frontage
e. benefits received
f. distance from outfall or treatment
plant;

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