Mattapoisett Bogs and Tripps Mill Brook Restoration

The Buzzards Bay Coalition (BBC) retained GZA to provide comprehensive planning, engineering, permitting and construction phase services for the restoration of Mattapoisett Bogs and Tripps Mill Brook. The purpose of the project was two-fold: 1) restore a former cranberry bog and associated feeder stream to pre-farming conditions; and 2) to improve the recreational experience of users through simplified, yet improved trails, stream/wetland crossings and parking improvements. 
 

Challenge

Restore an abandoned cranberry bog containing 28 water control structures to a self-regulating emergent marsh/open water wetland complex using nature-based features, while not increasing flood flows to downstream properties and while not importing or exporting soil - all within a limited budget.

Solution

GZA worked closely with the BBC and other stakeholders including the town, Massachusetts Division of Ecological Restoration (DER), and the National Resources Conservation Service (NRCS) to develop the alternatives, final design plans, permit applications, construction drawings and specifications. GZA conducted detailed H&H analysis of the Tripps Mill Brook and Bogs system under several design scenarios involving pedestrian bridge span crossings and cut-and-fill configurations. GZA also developed bog bridge designs to span areas subject to intentional flooding. GZA also designed a 2-acre turtle nesting site adjacent to the restored wetland. GZA performed geotechnical analyses and construction observation to support the erection of pedestrian bridges built by others. GZA redesigned the layout of over 2 miles of trails to develop a perimeter trail system that was sustainable yet provided ADA access to unique habitat features within the restored wetland. GZA also re-designed the existing parking lot to include additional capacity and to make it ADA compliant. Prior to final design, GZA produced renderings to assist in the promotion of this new and exciting project.
 

Benefit

Working closely with stakeholders, GZA designed a plan that met stakeholder goals and was ecologically sound and self-sustaining. The restored wetland provides significantly more function and value than the cranberry bog farm operation through improvement of hydrologic connection, wildlife and waterfowl habitat, nutrient retention and production export. In addition, this wetland significantly increases the overall contiguous wetland area in this portion of Mattapoisett given the adjacency of large shrub/scrub and forested wetlands. The conversion of the Tripps Mill Brook diversion channel has improved fish passage and overall riverine aesthetics for hikers. The improved trails and parking have improved user experience considerably by improving trail geometry and connections throughout the wetland and into adjacent recreational areas, allowing the reconstructed bog to thrive as a wetland and to provide improved pedestrian access to this ecosystem.