Culvert Design for the Restoration of the Weir Creek Salt Marsh in Dennis, MA

Natural Resources Conservation Service

NRCS Team: Ida Ngambeki, Leonora Baddoo, June Yeung, Meghan Irving

2006-2007: In collaboration with the Natural Resources Conservation Service (NRCS), this student team designed a new culvert for the Weir Creek Salt Marsh in Dennis MA to increase tidal flow into the marsh without flooding any of the surrounding homes.  When Lower County Road was built through the Weir Creek Salt Marsh, it cut off a large part of the marsh from the ocean.  The undersized culvert under the road was too small, restricting tidal flow through the marsh, and negatively impacting the surrounding ecosystem and built environment.  Upgrading the culvert was part of the Massachusetts Office of Coastal Zone Management’s Wetland Restoration Program.

On-site, the team collected tidal, precipitation, and topographic data to define the current conditions of the marsh.  The team then developed and calibrated two different hydrologic/hydraulic models for the site and then tested several culvert design options in the models to evaluate tidal and runoff flows through the marsh under simulated conditions.  The team selected their recommended culvert design based on a cost-benefit analysis, restoration area size, and risk of flooding. The team prepared detailed construction drawings and specifications, an evaluation of tidal flows, and an operation and maintenance plan for the proposed culvert.  The NRCS is overseeing the permitting process, acquisition of funds, and ultimate implementation.