MS4

The CT Department of Energy and Environmental Protection (DEEP) issued a new General Permit for the Discharge of Stormwater from Small Municipal Separate Storm Sewer Systems (MS4) on January 20, 2016. The permit applies to all NVCOG municipalities with the exception of Bethlehem, and represents a marked increase in municipal responsibility in the management of stormwater and stormwater infrastructure over the previous permit originally issued in 2004. 

New Requirements

The new permit retains the original 6 Minimum Control Measures found in the previous permit, but prescribes more comprehensive compliance requirements.  An overview of the new requirements by control measure can be seen below. NVCOG staff has prepared this detailed comparison between the previous and new permits: MS4 Detailed Comparison

1. Public Education and Outreach
    • Additional targeted outreach for specific pollutants
2. Public Participation
    • Public comment period for Stormwater Management Plan and Annual Reports (30 Days)
3. Illicit Discharge Detection and Elimination (IDDE)
    • Written IDDE program based on extensive permit protocol
    • Outfall screening program
    • Establish legal authority to prohibit and control illicit discharges and impose fines
    • Develop citizen reporting system
    • Map entire MS4 in priority areas
4. Construction Site Stormwater Runoff Control
    • Requires consistency with the DEEP Stormwater Quality Manual and 2002 Soil Erosion and Sediment Control Guidelines
    • Required written Interdepartmental Coordination Plan
    • More detailed sirte inspection and maintenance requirements
    • Town must notify applicants of the DEEP Construction General Permit
    • New legal authorities
5. Post -Construction Stormwater Management
    • Requires the elimination of obstacles to Low Impact Development* (LID) in municipal regulations and ordinances
    • Requires long term maintenance planning for existing and proposed stormwater infrastructure
    • More stringent requirements for on -site stormwater retention
    • Map Directly Connected Impervious Area 
    • Stormwater structure inspection and cleaning program
    • New legal authorities
6. Pollution Prevention/ Good Housekeeping
    • New staff training requirements
    • Retrofit program with annual tracking - disconnect 2% of DCIA* within 5 years
    • Requirements for property management and maintenance procedures to minimize stormwater pollution
    • Street sweeping program
    • Leaf management program
    • Catch basin clean out program

Statewide Assistance

UConn CLEAR

UConn's Center for Land Use Education and Research (CLEAR) Nonpoint Education for Municipal Officials (NEMO) program has been contracted by DEEP to provide MS4 assistance and outreach to municipalities.  They have developed the Connecticut MS4 Guide, an online resource that includes information, guidance, maps and tools to help Municipalities work through the permit process.  They have also developed a Stormwater Management Plan Template, a comprehensive interactive online map, and have a Municipal Stormwater Educator available to answer questions and provide assistance.   

Regional Assistance

Assistance with Stormwater Management Plan Updates and MS4 Program Registration

In order to assist municipalities with initial MS4 requirements, NVCOG has published a pre-qualified list of consultants that can provide assistance with required stormwater management plan updates and MS4 program registration.  You can view the list and qualifications on the MS4 Consultant On-Call List page.  

Public Outreach and Education

NVCOG has contracted with the Pomperaug River Watershed Coalition (PRWC) to provide public outreach materials through the RiverSmart program. By participating in the program, NVCOG municipalities were able to meet all outreach and education requirements of the previous MS4 General Permit.  NVCOG is working with PRWC to expand the program to include the new requirements, and we hope to continue to provide public outreach and education support for the new permit through the RiverSmart program. 

MS4 and LID Local Regulation Assessment 

NVCOG staff conducted assessments of all local regulations in the context of the required legal authorities and regulatory changes requires under the new permit. Changes to local regulations will likely be necessary specifically regarding three sections of the new MS4 permit: Illicit Discharge Detection and Elimination, Construction Site Stormwater Runoff Control, and Post Construction Stormwater Management. Detailed assessments have been provided to each NVCOG municipality along with suggestions to meet the permit requirements. Assessment reports and assistance available upon request, please contact Aaron Budris, abudris@nvcogct

Mapping Assistance

NVCOG staff is currently investigating the mapping requirements imposed by the new permit in consultation with DEEP, other COGs, and the GIS user community. UConn CLEAR has developed a comprehensive interactive online map to assist with MS4 Registration and Stormwater Management Plans.  

*Commonly Used Terms

DCIA - Directly Connected Impervious Area - means that impervious area from which stormwater runoff discharges directly to waters of the state or directly to a storm sewer system that discharges to waters of the state. 
LID - Low Impact Development - means a site design strategy that maintains, mimics or replicates pre-development hydrology through the use of numerous site design principles and smallscale treatment practices distributed throughout a site to manage runoff volume and water quality at the source. 
MS4 - Municipal Separate Storm Sewer System - means conveyances for stormwater (including roads with drainage systems, streets, catch basins, curbs, gutters, ditches, man-made channels or storm drains) owned or operated by any municipality or by any state or federal institution and discharging to surface waters of the state.
Priority Area -  Any area that is in a census designated urbanized area, drains to an impaired waterway, or has greater than 11% impervious cover.