Case Studies

Municipalities are required to manage stormwater due to the Clean Water Act which authorizes the Environmental Protection Agency (EPA) to regulate the discharge of polluted water from point sources, the most relevant being stormwater runoff in storm drains, into water bodies. This regulation is done through the National Pollutant Discharge Elimination System (NPDES) General Permit for Stormwater Discharges from Small Municipal Separate Storm Sewer Systems (MS4). NPDES requires that towns implement bylaws to manage stormwater as well as educate and involve the public in stormwater matters. The town must also ensure tidiness and prevent pollution in its operations. Despite having the same requirements, each town has confronted the stormwater problem differently.
Below are links to case studies which describe what Acton, Littleton, and Westford have been doing to manage stormwater:

Stormwater Management Efforts in Acton, MA

Low Impact Development (LID) is slowly gaining popularity in Acton. There have been a few small rain gardens and some porous pavement installed on public land. Some Acton officials, such as the current town planner, feel that more data is necessary to prove the effectiveness and reliability of LID. LID techniques are also being used in private areas. The Beacon Court Development in Acton used porous pavement on their private way and the Sarah Lane subdivision contains rain gardens and vegetated swales. The Acton Discovery Museum has LID techniques implemented as part of a demonstration exhibit.

Acton has recently developed the Water Resources Advisory Committee (WRAC) to help propose bylaw changes. Current relevant bylaws include Discharges to the Municipal Storm Drain System, Zoning, Subdivision Rules and Regulations, and Wetland Protection. These help the town be in compliance with federal and state stormwater requirements by preserving open space and wetlands as well as improving illicit discharge detection and elimination. There haven’t been many major changes to these bylaws recently, but Acton has worked to lessen excess requirements which only increased impervious surfaces. For instance, subdivision streets were originally required to be 36 feet wide, now the requirement is only 20feet. Furthering its efforts to be in compliance, Acton is currently in the process of drafting a new bylaw which would help control post construction stormwater runoff. Acton developed a stormwater management plan in 2003 in compliance with the EPA’s NPDES requirements. Acton also works to teach 4th and 5th graders about the importance of stormwater management and school curriculums often include trips to the wastewater treatment plant which utilizes groundwater discharge.

Stormwater Management Efforts in Littleton, MA:

Littleton has always been ahead of the curve on stormwater management. According to the Littleton Water Department’s General Manager, they were one of the first towns in the country with percent impervious coverage rules. Littleton considers itself to be “generally in compliance” with the NPDES General Permit for Storm Water Discharges from Small MS4s. The town hasn’t made any major changes to bylaws relevant to stormwater since 2007; around the same time that they created a Low Impact Design/Best Management Practices (BMPs) Manual to show what techniques were best for their town. It remained separate from the bylaws so that it could be updated easily. This manual shows which BMPs are best for Littleton and helps in the town’s endorsement of LID, though it prefers passive LID techniques to minimize risk. One site in Littleton which has been retrofitted with numerous LIDs is Long Lake. Some of the goals of this retrofit were to infiltrate stormwater as well as treat and improve the quality of water. LIDs on the site included the construction of 1.5 acres of wetland, 20 private and public rain gardens, porous pavement, 150 rain barrels, and vegetative swales. Littleton also has a water conservation program in effect called Drive to 65 which aims to limit homeowner’s water consumption to less than 65 gallons per day per resident.

Stormwater Management Efforts in Westford, MA:

Westford has been hesitant to install LID features under the town’s jurisdiction, preferring instead to monitor LIDs in privately-controlled areas so as to get more data on their reliability in a climate such as New England’s. There have, however, been two LID projects on public land. One is at the Norman E. Day School and is part of the Living Lab Program during which the Westford Engineering Department teaches 5th graders about the importance of stormwater. The other is a rain garden by Westford’s water department which was installed as part of an Eagle Scout project.

While only having a few LID projects, the town of Westford has numerous regulatory methods for managing stormwater and has been working hard to comply with the EPA’s NPDES requirements. Westford manages stormwater through the following bylaws: Discharges to the Municipal Storm Drain System Bylaw, Stormwater Management Bylaw and Regulations, Zoning Bylaw and Regulations, Wetlands Bylaw and Regulations, and Subdivision Rules and Regulations. These bylaws help to regulate illicit discharges, wetlands, site inspection and enforcement, erosion and sediment waste controls, construction site runoff, best management practices, long-term operation and maintenance, and site plan review procedures. In developing their stormwater bylaw, they started by consulting a stakeholder group including residents and developers. As a result, by the time it was ready for approval there were no objections.

To help manage stormwater, members of the Westford Engineering Department meet with neighborhoods to educate residents about what methods to use to fulfill their obligations to maintain LID features and stormwater structures. Going forward, municipal officials in Westford are planning to create a stormwater master plan. The goal of this master plan is threefold: 1) To gain a more comprehensive understanding of Westford’s stormwater system. 2) To determine what needs to be done to bring Westford in compliance with NPDES requirements. 3) To resolve how to pay for stormwater management costs, potentially through proposing a stormwater utility once they’ve prioritized investments.

Westford’s SW page