Lily Pond and the Aaron River Reservoir are the sole sources for drinking water servicing approximately 7,100 people in the town of Cohasset. Due to concerns of possible contamination to the pond’s surface and groundwater, the consultant to the
Board of Water Commissioners, Norfolk Ram Group, LLC (Norfolk), developed a Surface Water Supply Protection Plan for the town. The purpose of the Plan was to prevent, eliminate, and control actual and potential sources of contamination
within the watershed that could negatively impact the quality of drinking water provided by Lily Pond and the Aaron River Reservoir. The plan included recommendations for the use of Low Impact Development (LID) practices in developed
portions of the watershed to reduce contaminants in stormwater runoff.
Which Low Impact Development Practices Were Applied?
What Is the Project Scope, Timeline, and Budget?
The scope of the project included a demonstration rain garden at Lily Pond; four rain gardens on municipal sites; the Route 3A project that includes rain gardens, vegetated swales, and buffers; and 40 additional rain gardens—all of which were constructed in a two-year period.
To finance the project, the town used a Section 319 Non Point Source Competitive Grant provided by the U.S. Environmental Protection Agency (EPA) and the Massachusetts Department of Environmental Protection (MassDEP), and a loan through MassDEP’s Clean Water State Revolving Fund (SRF).
What Are the Benefits?
The improved system benefits the town by preventing pollutants and waterborne diseases from entering the water supply and lowering the costs associated with filtration and disinfection requirements. Specifically, this system will provide:
The new stormwater system may serve as a model project for other communities and for future nonpoint source reductions
within other areas of the watershed.
What Type of Operation and Maintenance (O&M) Is Required?
Cohasset intends to contract with a landscape company to maintain the rain garden beds,remove debris and sediment, re-mulch, and maintain the vegetation by removing damaged limbs and replacing diseased plants. No fertilizers will be used, and only native species will be planted. Operation and maintenance costs have not been generated to date but are estimated at $4,000 to $7,000 per year for the entire project.
What Were the Obstacles or Lessons Learned?
The neighborhoods in Cohasset that have been selected for the installation of the rain gardens consist of well maintained and landscaped yards. Therefore, the biggest initial obstacle was garnering support from residents in the neighborhood who had expressed concern about the visual effects of the,rain gardens that will lie in the right-of-way adjacent to their yards. To overcome these obstacles, a public outreach campaign was initiated, including the release of newspaper articles, presentations at state and local organizations, and the involvement of the Cohasset Garden Club in the selection of plant material suitable for Cohasset rain gardens. The success and beauty of
the demonstration project at Lily Pond will also help to ease any concern about aesthetics.
As another component of the public outreach campaign, an informational newsletter was developed to explain the purpose of the BMPs and the locations of the LID improvements. The newsletter will also report the water quality monitoring results
for nitrogen, phosphorus, and total suspended solids taken at the sampling locations within the watershed. The newsletter is expected to raise the awareness of the importance of stormwater management.
For More Information, Contact Michael Clark, Norfolk Ram Group LLC, email: mclark@norfolkram.com, telephone: 508-747-7900 x193.
Production Notes
written by Betsy Rickards | designed by Arden Miller | project manager Andrea Cooper
A publication of the Coastal Smart Growth Program, a cooperative effort of the Massachusetts Office of Coastal Zone Management and the Executive Office of Environmental Affairs. Finalized October 2006.