ABOUT THE PROJECT

Coastal environments can significantly buffer people and infrastructure from coastal storms and help mitigate the effects of sea level rise. This study is demonstrating these benefits by quantifying the wave attenuation and flood reduction benefits of salt marshes, submerged aquatic vegetation (SAV) and other natural and nature-based features (NNBF) along the shores of Maryland's Chesapeake and Atlantic Coastal bays. 

Hydrodynamic and habitat data collected at target field sites and updated Sea Level Affecting Marsh Model (SLAMM) results are being integrated into coupled local and regional hydrodynamic and wave models (ADCIRC + SWAN, XBeach) to demonstrate the wave attenuation benefits of coastal habitats across the Maryland coastline now and into the future. 

Model results will be used to:

• Calculate the economic value of the coastal protection benefits of NNBF via risk-reduction to infrastructure
• Provide relatable, local examples to advance coastal preservation efforts by agencies throughout the state
• Inform the state's management actions to maintain or enhance the ecosystem services of marshes
• Support local outreach and identification of adaptation solutions to enhance coastal ecosystem and community resilience
• Re-evaluate Chesapeake Bay SAV restoration goals
• Improve existing conservation prioritization tools. 

A Management Transition Advisory Group (MTAG) of federal, state and local partners is being consulted to ensure study results support the project's management and adaptation planning goals. Collectively, this body of work aims to incentivize, prioritize, and streamline efforts to conserve coastal landscapes, and thus the people that rely on them, both now and into the future.

Six sea level rise scenarios from Maryland's 2018 report (Sea Level Rise Projections for Maryland) were selected for this study and will be used to model future marsh migration. These scenarios incorporate multiple emissions pathways and projection probabilities for application to different audiences. 

Three storms were selected for hydrodynamic modeling. Hurricane Irene was selected to represent a high wave / low water level storm. Hurricane Isabel was selected to represent a high wave / high water level storm. A December 2020 Winter Blizzard was selected to represent a low wave / low water level storm.

Focus Areas: Shady Side Peninsula (Anne Arundel County) and Crisfield (Somerset County) were selected as western shore and eastern shore sites for scenario-modeling to quantify the benefits of various green/gray management strategies.

Fieldwork has been completed at Franklin Point State Park, Assateague State Park, Blackwater National Wildlife Refuge and the Chesapeake Bay Environmental Center living shoreline. Wave, water and current dynamics were successfully monitored along nature-based features including marshes, Phragmites, submerged aquatic vegetation and one living shoreline.

Project team members introduced the study to local and national audiences at two conferences in fall 2020: 1) Maryland Association of Floodplain and Stormwater Managers Conference; and 2) The National Coastal and Estuarine Virtual Summit. Both talks provided an overview of the project methods and expected outcomes. 

Marsh Modeling: Contractor Warren Pinnacle Consulting, Inc., completed runs of the Sea Level Affecting Marshes Model (SLAMM). Results include a final data layer of current landscape conditions, as well as decadal outputs under six sea level rise scenarios. 

SAV Modeling: Contractor Warren Pinnacle Consulting, Inc., completed development of the SAV model for Tangier Sound and the Choptank River. Predictions for future SAV presence/absence were modeled under approximately 0.4 meters of sea level rise by 2040 - 2050, 1 meter of sea level rise by 2070 and 2 meters of sea level rise by 2100.

Statewide Hydrodynamic Modeling: George Mason University validated regional coupled models (ADCIRC+SWAN+SLAMM) to investigate wave attenuation benefits of marshes under current and future sea level rise scenarios.

Scenario Modeling: Testing is in progress to prepare for scenario-based simulations that compare the benefits of various management actions under different storm and sea level rise conditions.

Ecosystem Services: Changes in blue carbon stock under 2 sea level rise scenarios were evaluated. Results are available here: Story Map.

Jackie Specht, jackie.specht@tnc.org, The Nature Conservancy
Celso Ferreira, cferrei3@gmu.edu, George Mason University
Nicole Carlozo, nicole.carlozo@maryland.gov, Maryland Department of Natural Resources

PROJECT TEAM