Dorchester Bay City Living Levee and Resiliency Design
Jacob San Antonio, PE, Chief Engineer - Water Resources, VHB (L) and Mark Costa, PE, LEED AP, ENV SP, Senior Water Resources Engineer, VHB (R)
More than a decade after Bayside Expo Center shut its doors in Dorchester, MA, the Dorchester Bay City project’s master plan was approved by the Boston Planning & Development Agency at its September meeting. Plans include the creation of a nearly six-million-square-foot resilient hub of residential housing, retail/restaurant, and commercial office/research space from what was mostly surface parking lots. Spanning more than 36 acres across three adjacent parcels, the Dorchester Bay City project will be a catalyst for the community transformation, with six acres of well-appointed parks and plazas that will be integrated into the extensive surrounding public spaces as part of a larger 20-acre public realm and open space plan.
Supporting Dorchester’s Resiliency Goals
The project site directly abuts Dorchester Bay and has been identified as a major flood pathway into the city of Boston during current and future coastal flood events. As part of this development, VHB is working with Accordia Partners, LLC, providing resiliency services, in addition to civil engineering and transportation planning.
VHB prepared the resiliency adaptation analysis and served as lead engineer for the 2,000-linear-foot nature-based vegetated living levee to protect the city of Boston from sea-level rise and storm surge for a 2070 100-year event. The project proposes a nature-based flood protection system consisting of a vegetated raised ridge along the seaward edge of the development as part of a district-scale barrier solution for the Columbia Point neighborhood. The design of the flood protection system included coastal wave modeling using the Simulating Waves Nearshore (SWAN), and FEMA Coastal Hazard Analysis Modeling Program (CHAMP) model. VHB also calculated the potential future coastal erosion of the abutting shoreline over the design life of the project, which was used to set the location of the flood protection system, set landward of the future limits of erosion. The design and permitting of these improvements involved close coordination with other district-scale flood improvement projects for the city.
100-year storm event in 2070
(No-build, existing conditions) - VHB Hydraulic Modeling
Other resiliency measures include a street system that will be built one foot above the minimum sea-level rise flood elevation, installation of a new stormwater management system on site, a funding contribution to DCR’s flood protection system in front of the Harbor Point apartments, and building a new flood protection system on DCR land behind Carson Beach that would connect to the future flood protection system in Moakley Park
As part of the project, VHB led outreach efforts and permitting with the Resiliency Working Group and coordination with state and city regulators, including Massachusetts Coastal Zone Management (CZM), Department of Conservation and Recreation (DCR), Department of Environmental Protection (DEP), and City of Boston officials.
The project is expected to include nine acres of permeable landscape, including 1,000 new trees to reduce a heat-island effect (approx. 30 degrees F reduction on surface temperatures) and waterfront green space with a playground and esplanade. Beyond the commercial space, the project includes approximately 1,957 residential units — 20 percent of which is set aside as affordable housing. The buildings will be designed to LEED Gold and Platinum, Passive House standards. Additionally, the Project will include hundreds of EV chargers.
Plans call for construction in three phases, with resiliency mitigation efforts planned in the project’s first phase. The project will also create 13,000 to 17,000 permanent jobs and is expected to take 10 to 15 years to be fully built, with approvals still needed for individual building designs and development plans.
Community benefits include $53.7 million to support affordable housing, $9.9 million for jobs training and $10 million for the Massachusetts Affordable Housing Alliance’s Saving Toward Affordable Sustainable Homeownership matched-savings program, which aims to reduce racial homeownership and wealth gaps.
VHB’s analysis for this transit-oriented development explored transit service and roadway infrastructure upgrades to appropriately support multimodal users, with a focus on complete streets design and enhanced walking and bicycling connections to the MBTA’s JFK/UMass Red Line station.
Dorchester Bay City Rendering with Living Levee
The $62 million for transportation improvements within the site itself includes reconstructing a portion of Mt. Vernon Street and building 3.7 miles of sidewalk-level bike lanes. The team also plans $23 million for Moakley Park to support ongoing maintenance and $41.6 million in off-site transportation improvements and mitigation.
By remaking three largely car-centric sites into a pedestrian and bike-friendly area, the project will help reshape the Dorchester neighborhood of Boston with improved circulation, creating connections to downtown Boston, the surrounding Dorchester and South Boston neighborhoods, UMass Boston, Moakley Park, the Boston Harbor, and the Harbor Walk.