The Coastal Resilience Grant Program provides funding and technical assistance to municipalities and nonprofits to advance innovative local efforts to address coastal flooding, erosion, and sea level rise impacts through communication and public outreach initiatives, vulnerability assessments, planning activities, engineering projects, and natural storm damage protection.
The summary below describes a featured Coastal Resilience Grant project to highlight the range of projects eligible for funding and to demonstrate some of the lessons learned through project implementation. Coastal Resilience Grant Program - Featured Projects provides links to additional examples.
In Fiscal Year (FY) 2014, the Town of Hull received a grant to redesign a revetment and seawall to reduce storm damage along Crescent Beach:
- Project Category: Redesign and Retrofit
- Summary: The town redesigned a revetment and seawall along Crescent Beach to account for sea level rise and reduce property damage, environmental impacts, and public safety threats. The project also included outreach to the neighborhood impacted by overwash during storm events to educate residents about strategies to limit the flow of overwash material into Straits Pond.
|Summary of Project Funding|
FY14 Grant Award: $41,250
Total Match: $13,750 (25% of total project cost)
Hull is located on a narrow, densely developed peninsula that juts into Massachusetts Bay at the southern extent of Boston Harbor. The town’s northeast-facing shoreline is exposed to repetitive flood and erosion impacts from coastal storms, threatening 4,000 properties, critical infrastructure, and natural resources.
One of Hull’s flooding “hot spots” is located along Crescent Beach, a quarter-mile stretch of barrier beach that is 250-500 feet wide. A deteriorating revetment and seawall run the length of Crescent Beach—and landward of the seawall are 73 homes, a critical evacuation route (Atlantic Avenue), and Straits Pond, which has been designated by the state as an Area of Critical Environmental Concern. The revetment was designed to withstand storm damage, but its smooth, cemented surface reduces its ability to dissipate wave energy and acts as a ramp that intensifies wave overtopping. The waves scour the area directly landward of the seawall and carry beach material and property debris (e.g. lumber, bricks, asphalt, and trash) over Atlantic Avenue and into Straits Pond.
The town applied for financial and technical assistance to evaluate shoreline protection alternatives that would minimize future storm damage and environmental impacts. The evaluation would be used to select a preferred strategy to help protect properties and critical infrastructure from increased flooding and sea level rise and reduce overwash material to Straits Pond.
Approach and Results
The project team considered a range of shore protection alternatives, including no action, beach nourishment, a submerged nearshore wave break structure, and repair and reconstruction of the seawall and revetment. The preferred alternative—repair and reconstruction of the seawall and revetment—was determined to best protect the shore and reduce wave overtopping while minimizing impacts to nearshore and offshore aquatic habitats.
Seven design options with different elevations and slopes were modeled under 100-year storm conditions to determine the best design for reducing the rate and volume of water overtopping the structures while minimizing impact on aquatic resources. The preferred design raises the top of the seawall by two feet and reconstructs the existing revetment with armor stones to better dissipate wave energy. This design strategy represents a compromise that balances cost, minimizes impacts to the seafloor environment, and reduces wave overtopping. The footprint of the proposed revetment will extend farther seaward than its existing location for the northern half of the project, resulting in coastal and marine impacts, although all efforts were made to keep as much of the revetment as possible in its current footprint. Seaward expansion of coastal infrastructure should generally be avoided, but as the alternatives analysis demonstrated, there were no other practical strategies at this site.
As part of the grant-funded project, the town submitted an Environmental Notification Form (ENF) to the Massachusetts Environmental Policy Act (MEPA) Office for review and approval as a first step in obtaining required federal, state, and local permits for project construction. The ENF includes the detailed alternatives analysis and the preferred seawall and revetment rehabilitation design strategy. (See the Town of Hull's Crescent Beach Seawall Project web page for links to the ENF and other documents.)
In 2015, the town was awarded an additional $3 million through the Massachusetts Dam and Seawall Repair or Removal Program to complete final design, permitting, and reconstruction of the seawall.
The town originally wanted to incorporate up to two feet of sea level rise into the project design. However, the coastal modeling and engineering assessment revealed that accommodating just a one-foot rise in sea level would require raising the top of the seawall four feet above its existing elevation to effectively mitigate storm damage, which would consequently require a larger revetment, expand environmental impacts, and increase project cost by 35 percent. The town decided to balance environmental and economic concerns and select an option that would improve the existing condition of the structure and its resilience to future storm impacts but not eliminate all overtopping.
Partners and Other Support
The project was managed by the Hull Conservation Commission. The town partnered with a coastal engineering firm with experience in wave and storm modeling and evaluating alternative shore protection strategies. The team also collaborated with the Straits Pond Watershed Association and CZM to work with residents on adopting property management measures to further reduce storm damage in conjunction with the seawall and revetment improvements.