Tuesday, May 18, 2010

Revised MS4 Stormwater Regulation - Post Construction Retrofit

In 2006, National Research Council (NRC) conducted a review of the US EPA stormwater program and recommend ways to strengthen it. The NRC Report, which was finalized in October 2008, found that the current stormwater program "...is not likely to adequately control stormwater's contribution to waterbody impairment." and recommended that EPA take action to address the effects of stormwater flow.

In response to this review, EPA is currently revising the municipal (MS4) stormwater program, and plans to establish requirements for managing stormwater discharges from new development and re-development. This action may also expand the areas subject to Municipal Separate Storm Sewer Systems (MS4) permits to include rapidly developing areas and to cover some discharges that are not currently regulated. A single set of stormwater requirements may be developed to combine both Phase I and Phase II MS4s. EPA currently believes that retrofitting for existing discharges may be addressed, although expectations for retrofitting will likely differ significantly from requirements for new- and re-development.

The initiative to revise the MS4 permitting program began in September 2009; EPA currently anticipates finalizing the revision in September 2011.

Caltha LLP provides expert consulting services to public and private sector clients nationwide to address Stormwater Permitting & Regulatory Support, Stormwater Pollution Prevention Plans (SWPPP), Stormwater Monitoring and Stormwater Training.

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