Formatted Title:

Mastic Beach Restoration: Using Nature-Based Solutions to Improve Resiliency and Restore a Tidal Marsh on Long Island, New York

Background/Objectives:

The Mastic Beach and Smith Point of Shirley peninsula is home to almost 13,000 residents and is located on the south shore of Long Island, Suffolk County, New York, in the southern portion of the Town of Brookhaven. The Town is one of eight “NY Rising Community Reconstruction” areas and has been impacted repeatedly by flooding due to sea level rise, storm surge, and rainfall. To respond to these threats, the Town instituted an extensive buy-out program to acquire and remove homes located in high-risk flood areas as part of a managed retreat program. In 2018 and 2020, the Town of Brookhaven was awarded a National Coastal Resilience (NCR) Grant from the National Fish and Wildlife Foundation (NFWF) to develop design plans for the restoration of coastal saltmarsh habitat in the community of southern Mastic Beach.

Approach/Activities:

As part of the restoration design process, extensive baseline surveys, sediment sampling and analysis, hydrodynamic modelling, and public outreach were conducted. The hydrodynamic studies showed that no one solution will solve the problem of flooding and storms in the area. Therefore, the project design focused on enhancing and reclaiming the existing 147-acre project floodplain in order to restore hydrologic and ecological function back to the marsh by enhancing and connecting critical fish and wildlife habitat. In addition, nature-based solutions (NBS), such as managed retreat and ecological restoration, were used to buffer inland flooding. As a result, this approach will:

Restore a saltmarsh ecosystem and provide improved habitat for at-risk organisms such as the Saltmarsh Sparrow.
Remove DDT-contaminated sediment located along roadsides, a result of historical mosquito control efforts, and transport it off Long Island to a disposal facility.
Reconnect the salt marsh with a natural floodplain through road removals and the development of tidal creeks.
Ecologically enhance the existing saltmarsh ecosystem through invasive species control.
Provide natural and nature-based features (NNBF), specifically maritime hammocks, to prevent coastal erosion and help buffer future flooding from inland/upland residential communities.
Allow stormwater to drain more efficiently during precipitation events and minimize wave impacts against private property.

Results/Lessons Learned:

As the Mastic Beach restoration project moves to finalize design and permitting, the following lessons have been realized:

Large restoration projects require extensive collaboration among stakeholders, including the local community, nonprofit organizations, and various levels of government (local, county, state, and federal).
Many seemingly untouched coastal marshes will have issues with pesticides such as DDT and will require extensive over-excavation and transport to remove sediment from the project.
Permitting large restoration and resiliency projects is time-consuming and costly.
Nature-based solutions mimicking natural site features can help reduce erosion and buffer future flooding from inland/upland residential communities.
Reestablishing tidal creeks can assist with marsh management, restore hydrologic connectivity, allow water to recede faster, and help control mosquitoes through the creation of Killifish habitat.

Alan Duckworth

Affiliation

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Mastic Beach Restoration: Using Nature-Based Solutions to Improve Resiliency and Restore a Tidal Marsh on Long Island, New York