Update on Stormwater Regulation

Update on
Stormwater Regulation
League of Cities
March 2011
Connie Bosma
Chief, Municipal Branch
Office of Wastewater Management
U.S. Environmental Protection Agency
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
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
▫ 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
• 1,000 Phase I MS4s
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:
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)
Urbanized areas in the U.S.
• About 6,000 Phase II MS4s
• Urbanized areas cover 2% of total U.S. land area
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.
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%.
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
Big Box
Big Box
Options for Performance Standards
• Discharges from New Development
Mimic predevelopment hydrology
Exceptions/alternative compliance options
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
• 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
▫ Possible population cutoff
Existing Discharge Management Plan
• 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
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
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
Green Infrastructure Approaches
Green roof
Rain garden
Rain garden
Parking lot infiltration
Open swale
Green Infrastructure Approaches
Open swale, Portland, OR
Porous pavement sidewalk
Terraced open swale
Porous pavers,
Large cistern, Chicago
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
• September 2011 – Proposal
• November 2012 – Final Action

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