The Dunshire Drive neighborhood in Chelmsford, Massachusetts, located in the floodplain of Deep Brook, is prone to flooding during severe storm events due to two 8-foot, corrugated metal, half-pipe culverts that are undersized and have exceeded their useful life. As a first step toward correcting these flooding issues, the town selected Weston & Sampson to assist with a Massachusetts Municipal Vulnerability Preparedness (MVP) Planning Grant Program funding application to design and permit necessary repairs. The goal of the project is to prevent failure of either culvert during a storm event that could result in isolation of the neighborhood and damage to residences.
Weston & Sampson began by conducting a topographical site survey of the area, performing a wetlands delineation, and gathering geotechnical information. We modeled climate change predictions to determine appropriate rainfall intensity for the new culvert designs under various scenarios. We conducted hydrologic and hydraulic analyses to evaluate the hydraulic capacity and flooding issues associated with the existing crossings as well as design alternatives to ensure appropriate design flow usage. Armed with that information, we developed a project design package that included the proposed culvert replacement options, incorporation of nature-based solutions including bioswales, erosion/sedimentation controls, project sequencing, and identification of easements required. Project permitting involved multiple federal, state, and local jurisdictions including the U.S. Army Corps of Engineers, Massachusetts Natural Heritage and Endangered Species Program, and the Chelmsford Conservation Commission, among others. We also helped the town conduct outreach to capture feedback, address community concerns, and to provide information about the public safety and climate resilience benefits associated with the proposed improvements.
With the growing frequency of extreme weather events and significant rainfall, this project will help protect the Dunshire Drive area from catastrophic flood-related damages, including isolation of the neighborhood due to inadequate drainage structures.
- community outreach, education, and engagement
- incorporation of nature-based solutions and strategies
- climate change modeling