Tag: Stormwater Engineering

MS4 Regulations in New Hampshire Communities: How to Deal with Stormwater

Storm Drain Photo

Whew!! You got that Notice of Intent form submitted (hopefully) to EPA on or before October 1. Now what? Grab a cold one, sit back, relax? Wishful thinking. Now the real fun begins.

Stormwater Sampling For those communities that have not already done so, stormwater outfalls from the MS4 area must be located, mapped and assigned a unique identification number. Then an inspection and condition assessment must be done for each outfall. If you were an MS4 community subject to the 2003 permit, you would have (or at least should have) completed this. However, you are not finished. Mapping completed pursuant to the 2003 MS4 permit must be updated with significantly more detail added per the 2017 MS4 permit. You have 2 years to complete the update. If you are a new MS4 community subject to the 2017 MS4 permit, you need to start this process and complete it within 3 years. For all MS4s, the stormwater mapping must be updated annually; and catch basins, catchment areas, manholes, and other features must be added. You must also complete an outfall inventory and ranking. The ranking is based on potential for illicit discharges and sanitary sewer overflows. Are we having fun yet??

If flow is observed from any outfalls during dry weather, it will be necessary to conduct dry-weather sampling and testing of each outfall in which dry-weather flow was observed in order to determine if there are potentially illicit discharges in the outfall. Outfalls must be ranked as “Problem”, “High-Priority”, “Low-Priority”, or “Excluded” based on known or suspected illicit discharges or sewer system overflows. This is all part of the required Illicit Discharge Detection and Elimination Program (IDDE). Did I mention you need to complete a written IDDE program within one year (by June 30, 2019)?

A number of New Hampshire communities are specifically listed in the 2017 MS4 permit based on discharges to waters with an approved Total Maximum Daily Load (TMDL) and/or based on discharges to certain water quality limited (impaired) waters without an approved TMDL. Approved TMDLs include chlorides, bacteria or pathogens, and phosphorus.

How is your Phosphorus Reduction Plan coming along?
Impairments to waters without an approved TMDL include: nitrogen, phosphorus, bacteria or pathogens, chloride, total suspended solids, metals, and oil and grease. Did you know that leaf litter contributes phosphorus and nitrogen to stormwater runoff?

How is your Chloride Reduction Plan coming along?
The written Plan has to be completed within 1 year (on or before June 30, 2019). There are also specific requirements for public education and outreach as well as public participation including messages and outreach to target audiences.

How are your stormwater regulations?
MS4 communities need to update their stormwater regulations and ordinances (if you already have them) or develop and implement regulations for managing stormwater (if you do not have them).

By the way, did I mention that all of the foregoing has to be addressed in your Stormwater Management Plan? The Hoyle, Tanner team of experts is available to assist you as needed with MS4 permit compliance. If you have questions, please contact me or Heidi Marshall for assistance.

5 Facts About Sustainable Stormwater Practices


In urban areas where numerous impervious surfaces are found, stormwater runoff is a significant contributor to water pollution. As rain falls in suburban and rural areas, the rain water is absorbed and filtered by the natural vegetation and soil in those areas. The impervious surfaces, including roofs and pavement, do not allow the ground to absorb the water therefore it is discharged without filtration into local water bodies either as direct runoff or through drainage systems.

Here we review 5 Facts About Sustainable Stormwater Practices to help communities and agencies thinking about developing new Green Infrastructure.

  1. Regulatory Compliance:Stormwater is regulated by the Environmental Protection Agency (EPA) under the Clean Water Act (CWA). This “establishes the basic structure for regulating discharges of pollutants into the waters of the United States and regulating quality standards for surface waters.” Thus making it “unlawful to discharge any pollutant from a point source into navigable waters, unless a permit was obtained.”1 In addition, some communities have developed Stormwater Management Plans to assist in the management of discharge from both private and public properties. Ordinances are used by local governments as an integral part of the municipal review of subdivisions and site plans diverting the cost with the use of fees charged for review of subdivisions and site plans. New stormwater regulations are being integrated into subdivision and site plan regulations to require implementation of sustainable stormwater management practices.
  2. Green Materials:“Green” or sustainable stormwater best management practices treat stormwater as a resource to be preserved and maintained, taking advantage of natural processes to clean and filter stormwater runoff. Vegetation and soil filtration highlight the obvious green materials used, but some methods growing in popularity include permeable pavement, down spout disconnection, rainwater harvesting, rain gardens, planter boxes, tree filters, green roofs, bioswales, as well as land conservation. With the incorporation of one or more of these design features, urban spaces will create less impervious surfaces thus reducing the amount of stormwater runoff.
  3. Public-Private Partnerships:State and local governments collaborating with developers on properties within different regions to incorporate Green Infrastructure into the design/redesign will in turn save money via diversion and treatment by the agencies. By offering tax credits or incentives to the developers, the adoption of these practices may grow quickly in popularity and use.
  4. Funding Availability:Many funding options are available through federal and state agencies including EPA, DOT, EDA, HUD, NOAA, as well as the Departments of Agriculture, Energy and Treasury. The available grants through these agencies will allow for municipal and private entities to make sustainable upgrades to existing or redeveloping sites.
  5. Benefits:Environmental – Increased stormwater, entering our water systems, contains pollutants from the surfaces it is diverted from potentially causing contaminated habitats for aquatic vegetation and wildlife. It can also cause physical problems such as erosion and flooding. With the use of Green Infrastructure, contaminants can be reduced in the receiving water bodies and create healthier environments. Social – Incorporating sustainable stormwater management practices can improve water quality, quantity and aesthetics thereby enhancing the livability of a community, create multifunctional landscapes and green spaces, encourage revitalization, and provide educational opportunities. Economic – The use of Green Infrastructure may provide opportunities to attract investment; reinvigorate deteriorating neighborhoods; inspire redevelopment; or provide recreational openings.

To find out more about community stormwater management practices, the EPA has issued a new guidebook outlining practices to assist while achieving other environmental, social and economic benefits. http://www.epa.gov/smartgrowth/green-infrastructure.html

1 http://www2.epa.gov/laws-regulations/summary-clean-water-act