Update on
Stormwater Regulation
League of Cities
March 2011
Connie Bosma
Chief, Municipal Branch
Office of Wastewater Management
U.S. Environmental Protection Agency
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402(p) of Clean Water Act
• Section 402(p) established phased approach to permitting certain
stormwater discharges
• Section 402(p)(4) required EPA to establish permit application
requirements for industrial and large municipal discharges (greater
than 100,000 population)
• Section 402(p)(5) required EPA to conduct a study to identify other
dischargers, assess their pollutant loadings and establish methods to control
the pollutants and submit the results in a report to Congress
• Section 402(p)(6) provides authority for EPA to regulate other
stormwater sources, as presented in the study, “to protect water
quality”
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Phase I Stormwater Regulations
• Finalized in 1990
• Regulates stormwater discharges from:
▫ 10 categories of industrial operations
▫ Construction activity disturbing 5 acres or more is one industrial
category
▫ Medium and large municipal separate storm sewer systems (MS4s) in
areas that serve 100,000 or more people
• Established:
▫ Permit application requirements and deadlines
▫ Requirements for a municipal stormwater management plan
▫ Permit exclusion for industrial activities that are not exposed to
stormwater
• 1,000 Phase I MS4s
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Phase II Stormwater Regulations
• Finalized in 1999
• Regulates stormwater discharges from:
▫ Small MS4s, defined as:
 An MS4 not already covered by an MS4 permit and
 Located in an “urbanized area” as defined by the Bureau of Census, or
 Designated by the NPDES permitting authority on a case-by-case basis if
situated outside of urbanized areas.
▫ Construction activities disturbing between one and five acres
▫ Requires NPDES permits for these discharges
• Established six minimum control measures for small MS4 permits:
1.
2.
3.
4.
5.
6.
Public Education & Outreach
Public Participation/Involvement
Illicit Discharge Detection & Elimination
Construction Site Runoff Control
Post-Construction Runoff Control
Pollution Prevention/Good Housekeeping
• Basis for regulation: 1995 Report to Congress and 402(p)(6)
authority
Urbanized areas in the U.S.
• About 6,000 Phase II MS4s
• Urbanized areas cover 2% of total U.S. land area
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Environmental Problem
• Stormwater contains pollutants including: nutrients, heavy
metals, bacteria, sediments, trash, salinity, PAHs,
temperature and pesticides
 Beach closures, prohibition or restrictions of shellfish
harvesting, wetland degradation
• The velocity of stormwater discharges can cause
downstream flooding, infrastructure damage, stream bank
erosion and habitat destruction
• Low levels of imperviousness directly impact biological
condition in receiving waters. There is also loss in base flow
in streams and groundwater recharge.
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Impacts of urbanization on stormwater runoff
Stormwater Impacts Will Worsen
• Nationwide, the amount of land area identified as urban
increased nearly 6% between 1990 - 2000, (U.S. Census)
• Between 1970 – 2000, there was a 9.4% net increase in
urban lands on the East Coast alone (USGS)
• Projected Growth
 Impervious surfaces covered 97,200 km2 of the conterminous
US in 2000.
 By 2030, impervious surface from housing development alone
will grow 36%.
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Program Challenges
• Significant development has occurred outside of regulated areas
• Since requirements vary across a state, there is no level playing
field, providing an incentive to develop outside of regulated areas
• It is more cost-effective to incorporate proper stormwater
control measures in the design of a site rather than retrofit
controls at a later date
• Discharges within regulated areas not adequately controlled
▫ Requirements too vague and unenforceable
▫ Inconsistencies across the nation
Planned
Big Box
Big
Box
Big
Box
Big
Box
Planned
Big Box
Big
Box
Options for Performance Standards
• Discharges from New Development
▫
▫
▫
▫
Mimic predevelopment hydrology
Exceptions/alternative compliance options
Credits
State flexibility
• Discharges from Redevelopment
▫ Additional exceptions/alternative compliance options
▫ State flexibility
• Exploring alternative compliance options for roads
Discharges from Individual Sites
• Benefits
▫ Protects water bodies from stormwater dischargers
▫ Provides level playing field
• Assess options for regulating discharges from
individual sites
▫ Size thresholds
▫ Location (discharges to the MS4; dischargers directly
to waters of the U.S.)
• How to regulate (permit and/or direct rule)
Regulated MS4 Expansion
Options
• No change – 2010 Urbanized Area defined by Census
• Extend coverage to jurisdiction boundaries of the MS4 rather
than urbanized area boundary
• Extend coverage to urbanized clusters (Census)
▫ Possible population cutoff
• Extend coverage to watershed boundaries (using HUC defined
watershed)
▫ Possible population cutoff
Existing Discharge Management Plan
(Retrofits)
• Possible requirements imposed on some MS4s
▫ Develop plan
▫ Implement plan over long period of time
• Options for Applicability
▫ Phase I MS4s
▫ Phase I and II MS4s
▫ MS4s that discharge to waters impaired by
stormwater
Chesapeake Bay
Potential specific provisions
• Regulate additional MS4s
• Apply performance standard to smaller site sizes
• Require retrofits of individual sites to better
address stormwater discharges
• Restrict fertilizers
Shift in Paradigm
Traditional approach – convey
stormwater quickly from site to
waterbody or detention pond
New approach –
view stormwater as a resource
manage on-site using green
infrastructure
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Green Infrastructure
• Green Infrastructure refers to practices that use or mimic natural
processes to infiltrate, evapotranspirate, or harvest stormwater near
the site where it was generated.
• It differs from traditional approaches to stormwater management
which focus primarily on flood control by piping stormwater to
central outfalls and discharging to receiving streams or large
detention basins
• Retaining stormwater discharge volumes on site reduces pollutant
loads and stream erosion
• Green infrastructure has many other benefits
▫ Recharge groundwater, provide greenspace, improve air quality,
reduce heat island effect
▫ Cost-effective
▫ Community liveability
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Green Infrastructure Approaches
Green roof
Rain garden
Rain garden
Parking lot infiltration
island
Open swale
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Green Infrastructure Approaches
Open swale, Portland, OR
Porous pavement sidewalk
Terraced open swale
Porous pavers,
Philadelphia
Large cistern, Chicago
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Green Infrastructure Implementation
• States are integrating green infrastructure principles into their permits
▫ Washington, DC
- Massachusetts - New York
▫ North Carolina
- Montana
- Maryland
▫ New Jersey
- Oregon
- Wisconsin
▫ Ohio
- Connecticut
- Kansas
▫ West Virginia
- Maine
- Colorado
▫ California
- Vermont
- Washington
• Communities are adopting green infrastructure approaches
▫ Philadelphia, PA
▫ Milwaukee, WI
▫ Chicago, IL
▫ Portland, OR
▫ Seattle, WA
▫ Kansas City, MO
▫ Louisville, KY
▫ Richmond, VA
Schedule
• September 2011 – Proposal
• November 2012 – Final Action