Prepare for the New Hampshire MS4 Permit

The United States Environmental Protection Agency recently released the new General Permit for Stormwater Discharges from Small Municipal Separate Storm Sewer Systems, more commonly referred to as the MS4 General Permit, with an effective date of July 1, 2018. This permit is designed to reduce stormwater pollution in New Hampshire by requiring affected municipalities to develop different plans to reduce, manage or control stormwater. It is authorized by § 402(p)(3)(B)(iii) of the Clean Water Act.

Stormwater is the largest source of water quality impairment in New Hampshire. Rain (or snow or ice melt) falls on land during a storm and picks up harmful pollutants as it flows into our lakes, streams, rivers and, ultimately, the ocean.  These pollutants include all manner of harmful substances, including pesticides, fertilizers, pathogens, nutrients and sediments, which can have negative impacts on our state’s waters. Often, these impacts are more pronounced in urban areas where impervious surfaces collect these pollutants and funnel them through flow pathways engineered to provide rapid drainage. While this infrastructure is designed to reduce flooding, the highly efficient pathways for stormwater also increases pollutant loads and reduces natural pollutant buffers.

The MS4 General Permit provides an opportunity to improve water quality by reducing the impacts of stormwater. The permit is designed to allow individual municipalities to create tailored plans to control stormwater discharge from municipal discharge points to the “Maximum Extent Practicable” by focusing on six different minimum control measures. The minimum control measures included in the MS4 General Permit include:

1. Public education and outreach;
2. Public involvement and participation;
3. Illicit discharge detection and elimination;
4. Construction site storm water runoff control;
5. Storm water management in new development and redevelopment; and,
6. Good house keeping and pollution prevention for municipal operations.

These measures include different strategies for improving water quality. For example, public education and participation control measures incorporate the municipality’s citizens in a cooperative manner. The illicit discharge control measure, in comparison, is designed for municipalities to identify and eliminate unauthorized connections to the storm sewer system. These might include legacy connections from before a wastewater disposal system was constructed, or illegal connections by people or corporations trying to bypass legal permitting avenues. Since each municipality is different, the control measure that will be most effective might also differ among municipalities. While there is some flexibility in the implementation of the different programs, each municipality must address each of the minimum control measures.

The good news for municipalities is that they do not need to implement each of these control measures by July 1, 2018. Instead, the affected municipalities have phased requirements, with the first requirement, the Notice of Intent, due on October 1, 2018.  Most of the written procedures for the minimum control measures must be completed by June 30, 2019.

About the Author: Nathaniel B. Morse

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