A new guidance document was recently developed by the Center for Watershed Protection to assist regulated small municipal separate storm sewer system (MS4) communities in Massachusetts develop an offsite mitigation program for redevelopment projects.
Starting July 1, 2018, a new Massachusetts Small MS4 General Permit went into effect. Through this permit, EPA Region 1 established a new stormwater performance standard for redevelopment projects within regulated small MS4 communities. The standard requires these projects to retain stormwater runoff and/or provide pollutant removal. Recognizing that this may be a challenge on many redevelopment sites, the new permit provides flexibility by allowing redevelopment sites to utilize offsite mitigation to meet the equivalent retention and pollutant removal permit requirements.
Given that many of the small MS4s impacted by the new permit have limited staff and expertise to develop an effective program, the Pioneer Valley Planning Commission (PVPC) saw the need for technical guidance to assist for these MS4s that would like to develop an offsite mitigation program and hired the Center to develop a guidance document. This project was funded through an MS4 Municipal Assistance Grant from the Massachusetts Department of Environmental Protection.
The project partners included PVPC, Berkshire Regional Planning Commission, Central Massachusetts Regional Planning Commission, Merrimack Valley Planning Commission, Metropolitan Area Planning Commission, Neponset River Watershed Association, and Northern Middlesex Regional Planning Commission. An advisory group of experts from across the state was convened by PVPC to provide guidance on the project. As part of the background research for the manual, the Center conducted interviews with municipal officials from Framingham, Milton, Pepperell, and South Hadley. A draft version of the document was circulated for review to municipalities across the state. The manual covers the offsite compliance and offsite hierarchy options, program considerations, and steps to build the program. It also include resources such as model language for stormwater management ordinances and example applications.
The guidance document will help to ensure that standards for offsite mitigation meet MS4 permit objectives for stormwater control and water quality protection, as well as legal requirements within the state of Massachusetts. The final document is available for download on the EPA Region 1 website and has been shared with MS4 communities across Massachusetts so that they become informed about requirements for redevelopment projects and the off-site mitigation option: https://www.epa.gov/npdes-permits/stormwater-tools-new-england.
For more information about this project, contact Laura Gardner at llg@cwp.org.
