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MS4 Stormwater Permit Program and Great Bay
Brief Overview – EPA’s Stormwater Management Program
Clean Water Act – NPDES - 1987 Stormwater amendments
Two Phase approach to stormwater permitting Industrial activities Construction MS4s
Phase II stormwater management program promulgated in 1999 Construction > 1 acre but less than 5 Small MS4s (population served < 100,000)
2003 - General Permit for Small MS4s in MA and NH issued
2008 – MS4-2003 expired, Draft Permit for NH MS4s public notice
Final Permit expected early 2012
What is an MS4?
A municipal separate storm sewer system is: A conveyance or system of conveyances owned by
a state, city, town, or other public entity that discharges to waters of the U.S and is designed or used for collecting or conveying stormwater
Includes roads with drainage systems, municipal streets, catch basins,
curbs, gutters, ditches, man-made channels, or storm drains Does not include
Combined sewers Parts of publicly owned treatment works Private systems
Summary of NH MS4 permit issuance
Phase II regulated MS4s are those located in an urbanized area as defined by the latest Census NH Phase II regulated MS4s: 38 Traditional, 4 Non-
traditional, 7 Waivers
2003 Small MS4 GP covered regulated small MS4s in MA and NH, expired 2008 (administratively continued)
Draft NH Small MS4 General Permit issued for public notice 2008. MA versions issued in 2010 and 2011
Final Permit issuance expected early 2012 with spring 2012 effective date
Regulated MS4s in Great Bay Watershed
Brentwood* Chester* Danville Dover Durham East Kingston* Exeter Greenland Hampstead Hampton Falls* Kingston Lee* Madbury*
Milton Newington* North Hampton Portsmouth Rochester Rollinsford Sandown Somersworth NH DOT Strafford County
Commissioners UNH
* waiver under MS4-2003
Phase II regulated MS4s are those located in an “urbanized area” (Census definition)
Great Bay watershed MS4s:
MS4 Permit Structure
Technology standard: reduce discharge of pollutants to the “Maximum Extent Practicable”
Implemented through requirements for six “minimum control measures” Public education and outreach Public participation Illicit discharge detection and elimination Construction stormwater management Post-construction (development/redevelopment) Municipal good housekeeping/pollution prevention
Water Quality based requirements & TMDLs
MS4 Implementation
Stormwater Management Program (SWMP) “Best management practices” (BMPs) to
implement six minimum controls and water quality based requirements
Annual assessment and reportingReports available on EPA website
http://www.epa.gov/region1/npdes/stormwater/2003-permit-archives.html
Public Education and Outreach
2003- General program requirement
Draft reissuance Specific audiences for
education Specific education topics Specific number of
educational messages Evaluation of the
effectiveness of educational messages
Illicit Discharge Detection and Elimination (IDDE) Program
2003 permit: ordinance/regulatory mechanism, outfall map, establish procedures
Draft reissuance: Complete system map More specific requirements for:
Assessment of MS4 for illicit discharge potential Systematic procedure for locating and removing illicit
connections, includes outfall inventory & monitoring Prevent illicit discharges and SSOs Track program success Annual employee training
Sampling/monitoring
Construction
2003 Permit –Ordinance/ regulatory mechanism
Draft reissuanceSite plan review processSite inspections and
enforcementEducation
Post-Construction
2003 Permit – Ordinance/ regulatory mechanism covering new development and redevelopment
Draft reissuance Regulatory program requirements for
plan review, design criteria (1” capture), BMP maintenance requirements
Assessment of street design to support low impact development
Assessment of regulations to allow green infrastructure practices
Tracking impervious areas (IA) and implement efforts to reduce IA
www.cwp.org
Good House Keeping
2003 Permit - Develop a written program to prevent/reduce stormwater pollution from municipal activities and facilities
Draft reissuance Standard operating procedures –
parks, buildings, vehicles, and roads Specific infrastructure maintenance
requirements Stormwater Pollution Prevention
Plans (SWPPP) for maintenance garages and waste handling facilities
Facility inspections Employee training
Water Quality Requirements
TMDLsSpecific applicable BMPs identified
Discharges to Impaired WatersBMPs addressing pollutant of concern to be
included in SWMP
Nitrogen Reduction Potential through MS4 Requirements
Target minimum Controls relevant to N reduction Education – fertilizer use, septic system maintenance IDDE – illicit discharges are potentially large source of
nitrogen loads Post-Construction – require stormwater management
effective in control of N, LID Good House Keeping – fertilizer use, infrastructure
maintenance Water Quality based requirements – Final permit
to include specific N requirements for Great Bay watershed
