Stormwater Information for General Public

What is Stormwater?

 The Purpose of the Stormwater Management Program 

Concentrated development in urbanized areas substantially increases impervious surfaces such as paved streets, driveways, parking lots, and sidewalks, in which pollutants from concentrated human activities settle and remain until a storm event washes them into nearby storm drains. Polluted stormwater runoff transported to municipal separate storm sewer systems (MS4s) ultimately discharge into local rivers and streams without treatment. EPA's Stormwater Phase II Rule establishes a MS4 stormwater management program that is intended to improve the water quality of waterways by reducing the quantity of pollutants that stormwaters pick up and carry into storm sewer systems during storm events. Common pollutants include oil and grease from roadways, pesticides from lawns, pet waste, sediment from construction sites, and carelessly discarded trash, such as cigarette butts, paper wrappers, and plastic bottles. When discharged into streams and rivers, these pollutants can impair the waterways, discouraging recreational use, contaminating drinking water supplies, and interfering with the habitat of fish, other aquatic organisms, and wildlife.

 Bridge 3 wingwall POST CONST

The Phase II program is designed to accommodate a general permit approach using a Notice of Intent (NOI) as the application.

Municipalities located within the US Census Bureau's 2000 Urbanized Areas, which the Town of Goffstown is one of, are required to apply for the NPDES Permit coverage under the EPA Phase II Stormwater Permit Program. The following requirements for permit coverage apply to the Town of Goffstown:

  • The permit for MS4 operators will require the development of a stormwater management program that controls pollutants from all of the MS4 discharge points to the "Maximum Extent Practical."

The Phase II Rule defines a small MS4 stormwater management program comprising of the following six elements that, when implemented in concert, are expected to result in significant reductions of pollutants discharged into receiving waters:

  • Public Eduction

  • Public Participation

  • Illicit Discharge Detection and Elimination

  • Construction Site Stormwater Runoff Control

  • Post Construction Stormwater Management

  • Municipal Good Housekeeping

Stormwater discharge associated with industrial activity owned/ operated by the Town, such as Department of Public Works garage, are also required to obtain coverage under the Phase II program.  

Construction activity within any part of the Town for sites from one to five acres is also regulated under the Phase II EPA program. The permit will require the owner and operator of the construction site to perform the following:

  • Implement Erosion and Sediment Control Best Management Practices (BMPs)

  • Control wastes such as discarded building materials, concrete truck washout, and sanitary wastes.

  • Develop and implement a Stormwater Pollution Prevention Plan (to see the Town's Transfer Station SWPPP, click here).

  • Submit a Site Plan that incorporates consideration of potential water quality impacts.

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The Town is essentially a compliance regulator for stormwater systems for development projects. Local town subdivision and site plan review regulations reflect stormwater requirements. Instituting this stormwater management plan by the Town is a means for Goffstown to develop, implement, and enforce the reduction of pollutants in stormwater runoff from construction activities that result in land disturbance of greater than or equal to one acre. Some of the requirements in the Phase II rules may already be in place by the Town; however, they may need to be upgraded. These requirements would include:

  • Establish an ordinance or other regulatory mechanism requiring the implementation or proper erosion and sediment controls and controls for other wastes on applicable construction sites.

  • Have procedures for site plan review of proposed construction plans that consider potential water quality impacts.

  • Have procedures for site inspection and enforcement of control measures.

  • Have sanctions to ensure compliance (established in the ordinance or other regulatory mechanism).

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For more information about the Town of Goffstown's MS4 Permit and Stormwater Management Program, click here.


What We Do


 The Stormwater interns are responsible for analyzing and updating the conditions of impaired and at risk bodies of water in Goffstown. Inspections of outfalls detention ponds, and water sampling are conducted in the dry season to track the quality of water flowing into the streams, brooks, rivers, and lakes. Inspections and tests with poor results may suggest an illicit connection upstream. It is the responsibility of the Town to prevent the illegal discharge of pollutants into the waterways and take measures to fix these issues.

Outfalls are outlet pipes that carry stormwater into other bodies of water. There are many all over town that are inspected annually. If water is flowing through the outfall when there has been no recent rainfall, this can suggest an illicit connection. The inspections conducted look for physical signs of this, including damage to the outfall structure, vegetative growth, odor, turbidity, color, debris, and pollution.

Detention ponds and swales are catchment areas that are designed to filter and slow down the flow of water. There are also several of these around town that are inspected annually to determine their effectiveness. Attributes such as vegetation, sedimentation, slope protection, pond drainage, public hazards, and water conditions are taken into account during these inspections. Recently, the detention pond on Tyler Drive was reconstructed to better suit the needs of the drainage area and improve the condition of the surrounding stormwater.

Tyler Drive Detention Pond before: 

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Tyler Drive Detention Pond after:
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In conjunction with NHDES, water sampling at the major waterways in Goffstown have been  conducted for the past year. Samples are taken an specific points along Black Brook, Hardy Brook, Piscataquog River, Namaske Lake, Harry Brook, Bog Brook, St. Anselm's Brook, Riddle Brook, and Catamount Brook. These points are on the NH Threatened or Impaired Waters List. Water is tested for pH, dissolved oxygen, E. coli, chloride, lead, hardness, chlorophyll, total phosphorous, and iron. Samples are taken up to the lab located at the NHDES offices.