EPA has released a revised draft New Hapshire small “Municipal Separate Storm Sewer System” (MS4) General Permit for public review and comment. The draft general permit has been published in the Federal Register. Public comments must be submitted by April 15, 2013. The general permit will apply to 60 municipalities located in an urbanized area as defined by the 2010 census. Regulated MS4s include traditional cities and towns, state and federally owned facilities such as universities and military bases, and the state transportation agency (NHDOT). The draft general permits will apply to all the regulated MS4s, although waivers are possible for eligible municipalities within the urbanized area where population is less than 1,000.

The revised draft permit updates the previous general permit finalized in 2003. EPA previously released draft general permits for small MS4s in NH in 2008. EPA decided to release revised draft general permits to account for significant public comments received on the 2008 proposal, the availability of updated demographic information from the 2010 Census, and several recently approved TMDLs for various waters in New Hampshire.

The draft general permit, when finalized, would require regulated small MS4s to develop, implement and enforce a Stormwater Management Program (SWMP) designed to control pollutants to the maximum extent practicable, protect water quality and satisfy appropriate requirements of the federal Clean Water Act. The draft permit would do this with requirements to address waste load allocations associated with approved TMDLs for bacteria, phosphorus and chloride, and requirements to address discharges to impaired waters which do not have an approved TMDL.

The draft permit requires implementation of six minimum control measures, including: public education and outreach, public participation, illicit discharge detection and elimination, management of construction site runoff, management of runoff from new development and redevelopment, and good housekeeping in municipal operations. The draft permit identifies four target audiences for public education, details specific procedures to locate and remove illicit connections, encourages low impact development practices and identifies practices to address phosphorus, bacteria, chloride and nitrogen.

According to EPA, the new draft permit addresses many comments received on that earlier draft permit, including: (1) providing additional time for completing required tasks; (2) providing opportunities to optimize activities such as catch basin cleaning, rather that mandating a set frequency; (3) reducing the required frequency of street sweeping; (4) reducing costs associated with monitoring by allowing the use of field test kits; and (5) including provisions to address nitrogen in Great Bay. The revised draft permit removed provisions such as sweeping sidewalks and walking stream miles which were viewed as impractical by many commenters.

EPA has estimated the costs associated with implementation of the minimum control measures, but does not have sufficient information to reasonably estimate those associated with achievement of water quality based limitations found in established TMDLs. Actual municipality costs will vary depending on a number of factors including, but not limited to, population (1,000 to 100,000), resources, infrastructure (number of catch basins, road miles), size of the urbanized area, and work completed during previous permit term. As drafted, EPA estimates the cost to meet the requirements associated with implementation of the six minimum control measures to be between $78,000 and $829,000 per year averaged over the permit term.

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