Stormwater Regulatory Requirements

Stormwater discharges in the Town of Winthrop are regulated by the U.S. Environmental Protection Agency (EPA) under the National Pollutant Discharge Elimination System (NPDES) Phase II Stormwater Permit Program.

EPA’s Phase II Stormwater Program, issued in 1999, required small municipal storm sewer systems (MS4s) in urbanized areas (defined by the most recent U.S. census), as well as small MS4s outside the urbanized areas that are designated by the permitting authority, to obtain NPDES permit coverage for their stormwater discharges.   A map of Winthrop’s Regulated Area (Urbanized Area) is available here.

In May 2003, EPA Region 1 issued the “General Permit for Storm Water Discharges from Small Municipal Separate Storm Sewer Systems (MS4s)”, which regulates stormwater management activities for Phase II MS4s in Massachusetts and New Hampshire.  Information on all Massachusetts communities regulated by the Phase II Stormwater Program can be found here.

Objectives of the Phase II Stormwater Program are to reduce the discharge of stormwater pollutants to the maximum extent practicable, to protect water quality, and to satisfy the appropriate water quality requirements of the Clean Water Act.  To meet these objectives, EPA requires communities to develop community-specific Stormwater Management Plan (SWMP), which identifies Best Management Practices (BMPs) to address the following six “minimum control measures”:

1.  Public Education and Outreach
2.  Public Participation and Involvement
3.  Illicit Discharge Detection and Elimination
4.  Construction Site Runoff Control
5.  Post-Construction Runoff Control
6.  Pollution Prevention/Good Housekeeping for Municipal Operations

The full General Permit, which explains the requirements of the program in detail, is available here.

What is Winthrop doing?

Winthrop submitted their Notice of Intent (NOI) to EPA and MassDEP in 2003.  The NOI identified BMPs that the Town included in their stormwater management program to comply with the terms of the General Permit.  Annual Reports are submitted to EPA and MassDEP describing the Town’s stormwater activities each year.   The NOI and Annual reports are available on EPA’s website.