Cambridge Stormwater Wetland
Client: City of Cambridge Department of Public Works, Massachusetts
The City of Cambridge was required to construct a stormwater management basin under a project to eliminate Combined Sewer Overflows (CSOs) to the Alewife Brook. Land owned by the Massachusetts Department of Conservation and Recreation (DCR) was identified as the most feasible location to construct the basin. The challenge was to design a constructed wetland and detention basin that met the technical requirements for detention and treatment while simultaneously meeting the habitat and recreational functions envisioned for the area in the DCR Master Plan for the Alewife Brook Reservation.
The Interdisciplinary Approach
Chester Engineers designed the stormwater management facility as a multifunctional wetland that serves many objectives. Scope included the formulation of alternatives, public meetings and outreach, MEPA and other permitting support, responses to comments, wildlife inventory, and bioengineering design of the detention basin as a stormwater wetland park. The wetland is designed to minimize flooding of the Alewife Brook by retaining stormwater to shave peak flows during major storm events. The wetland provides treatment of “first flush” via sediment removal, biological filtration, and thermal regulation while providing recreational trails, enhanced wildlife habitat and wetlands, and an educational feature promoting stormwater management best practices. Our team also improved public access to the Reservation and designed amenities including an amphitheater, boardwalks, overlooks, benches, and interpretive historical, ecological, and hydrological signage.
The Sustainable Result
Described in the Boston Globe as “a far cry from the traditional treatment prescribed by engineers,” the stormwater wetland incorporates both conventional and bioengineered structures designed with a natural “look and feel” that won praise from stakeholder groups. The wetland increases base flows in the brook and enhances the health of adjacent natural wetlands. The stormwater management park layout and vegetation illustrates the synergistic relationships with existing ecological patterns and processes that provide a significant improvement over existing degraded habitat. The City was delighted to save more than $15 million dollars compared to the alternatives, and the DCR was pleased to have a cost-sharing partner to implement elements of its Master Plan—a win for those parties as well as the natural systems and local communities.
- Project Highlights:
- Integration of bioengineering and conventional structure
- Habitat enhancement
- Stormwater detention in an ecologically constructed manner
- Educational opportunities
- Pedestrian access and recreational opportunities
- Services Provided:
- Stormwater Wetland Design
- MEPA Permitting Support
- Public Outreach
- Landscape Architecture
- Site/Civil Engineering