.Uniteil States
Environmental Protection
Agency
Office of Water
(4503F) . -
EPA-841-F-96-004G
March 1996
4>EPA Nonpoint Pointers
Understanding and managing nonpoint source pollution in your community
Managing
Urban Runoff
The mosfrecent National Water Quality Invenforyjeports that runoff from
urban areas is the leading source of impairments to surveyed estuaries and
the third largest source of water quality impairments to surveyed lakes. In
addition, population and development trends indicate that by 2010 more,
than half of the Nation will live in coastal towns and cities, some rof which
jvill have tripled in population. Runoff from these areas will continue to
.degrade coastal waters. , 7.
- To protect surface water and ground vrater quality, urban development
and household activities must be guided by plans that limit runoff and
reduce pollutant loadings. Communities can address urban water quality •_•
, problems on both a local and watershed level and garner the institutional
support to help address urban runoff problems.
Nonporous urban landscapes
tike roads, bridges, parking lots,
and buildings don't let runoff
slowly percolate into the
ground.
_ How Urban Areas Affect ~
Runoff
- Increased Runoff. The porous
- and varied terrain of natural _
- _. landscapes like forests, wetlands,
and grasslands'trap rainwater and
snowmelt and allow it to filter
slowly into the ground. Runoff
— -..". - "" ~p C reaches receiving waters gradu-; :
ally. In contrast, nonporous urban landscapes like roads, bridges, parking
lots, and buildings don't let runoff slowly percolate into the ground. Water
remains at the surface, accumulates, and runs off in large amounts. When
leaving the system and emptying into a stream, it erodes streambanks,
damages streamside vegetation, and widens strearri channels. This will ::•
result in lower-water depths during non-storm periods, higher than normal
.water levels during wet weather periods, increased sediment loads, and _'
higher water temperatures. Native fish and other aquatic life cannot survive
in urban streams severely impacted by urban runoff. •••• - •'--•
Increased Pollutant Loads. Urbanization also increases the variety and
amount of pollutants transported to receiving waters: sediment from devel-
opment andhew construction; oil, grease, and toxic chemicals from vehicles;
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RELATED PUBLICATIONS
• Additional fact sheets in the
Nonpoint Pointers series
(EPA-841-F-96-004)
• Controlling Nonpoint Source
Runoff From Roads, High-
ways, and Bridges (EPA-
841-F-95-008a)
• Developing Successful
Runoff Control Programs for
Urbanized Areas (EPA-841 -
K-94-003)
• Economic Benefits of Runoff
Controls (EPA-S-95-OQ21L
», , .^Fundamentals of UrBan
S Washington, 'DC, t994
"T1"GuidanceJSpecirylng
Management Measures for
Sources of Nonpoint Pollu-
tion in Coastal Waters,
Chapter 4 (EPA-840-B-92-~
rlS,,,,,,,,,,,,,,,,,,,,,,--,,
! Storm Water Fact Sheet
Q04
order any of the above EPA
'"
Enyirorjmen^
tal Publications and Information.
Tel (513)489-8190
Fax (513) 489-8695
FOR MORE INFORMATION
- U.S. Environmental Protection
Agency
Nonpoint Source Control Branch
Washington DC 20460
Internet Address:
http//www.epa.gov/owow/nps/
index.html
nutrients and pesticides from turf management and gardening; viruses and
bacteria from failing septic systems; road salts; and heavy metals. Sediments
and solids constitute the largest volume of pollutant loads tQ receiving
waters in urban areas.
When runoff enters storm drains, it carries many of these pollutants with
it. In older cities, this polluted runoff is often released directly into the water
without any treatment. Increased pollutant loads can harm fish and wildlife
populations, kill native vegetation, foul drinking water supplies, and make
recreational areas unsafe. ~
Point and Nonpoint Distinctions
Two types of laws help control urban runoff: one focusing on urban point
sources and the other on urban nonpoint sources. Point sources are ad-
dressed by the National Pollution Discharge Elimination System permit
program of the Clean Water Act, which regulates stormwater discharges. :
Urban nonpoint sources are covered by nonpoint source management
programs developed by states, territories, and tribes under the Clean Water
Act. In states and territories with coastal zones, programs to protect coastal
waters from nonpoint source pollution also are required by section 6217 of
the Coastal Zone Act Reauthorization Amendments.
Measures to Manage Urban Runoff
Plans for New Development. New developments should attempt to
maintain the volume of runoff at predevelopment" levels by using structural
controls and pollution prevention strategies. Plans for the management of
runoff, sediment, toxics, and nutrients can establish guidelines to help
achieve both goals. Management plans are designed to protect sensitive
ecological areas, minimize land disturbances, and retain natural drainage
and vegetation.
Plans for Existing Development. Controlling runoff from existing urban
areas tends to be expensive compared to managing runoff from new devel-
opments. However, existing urban areas can target their urban runoff
control projects to make them more economical. Runoff management plans
for existing areas, can first identify priority pollutant reduction opportuni-
ties, then protect natural areas that help control runoff, and finally begin
ecological restoration and retrofit activities to clean up degraded water
bodies. Citizens can help prioritize clean-up strategies, volunteer for restora-
tion efforts, and help protect ecologically valuable areas.
Plans for On-site Disposal Systems. The control of nutrient and patho-
gen loadings to surface waters can begin with the proper design, installa-
tion, and operation of on-site disposal systems (OSDSs). These septic sys-
tems should be situated away from open waters and sensitive resources
such as wetlands and floodplains. They should also be inspected, pumped
out, and repaired at regular time intervals. Househpld maintenance of septic
systems can play a large role in preventing excessive system discharges.
Public Education. Schools can conduct education projects that teach
students how to prevent pollution and keep water clean. Education and
public outreach can target specific enterprises, such as service stations, that
Dpprtunities to control runoff on site. Many communities have
" djscouragepeor5l£lrom_
___
:>ing trasrTcfirectlv into storm sewer systems.
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