Quantifying the Benefits of Natural and Nature-Based Features in Maryland's Chesapeake and Atlantic Coastal Bays to Inform Conservation and Management under Future Sea Level Rise Scenarios

The Chesapeake Bay region has one of the highest rates of relative sea level rise (SLR) in the U.S., due to a combination of rising waters and land subsidence. The State of Maryland is already developing plans to adapt to the impacts from one foot of SLR observed over the past century, as well as the expected two additional feet of SLR in the next 30 years. However, the state does not currently have the planning tools or expected outcomes of preserving and restoring coastal habitat in terms of flood protections services in order to mitigate the impacts of SLR. This presentation will describe a collaboration between academic, governmental, and non-profit institutions aiming to quantify 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. We measured hydrodynamic conditions at three sites representing a range of native and invasive, submergent and emergent vegetation. Measurements include water levels, currents, wave heights, and vegetation characteristics important to wave attenuation. To augment the field-derived insights on the capability of NNBF to mitigate storm surge and waves as well as develop guidance on potential statewide protection, we employed field-validated numerical models i.e. ADCIRC-SWAN and XBeach. By measuring additional sites, including living shorelines and other vegetation types, we can further refine the numerical models and ultimately calculate statewide flood protection capacity of NNBF and the economic value of coastal protection benefits via risk-reduction to infrastructure. This work is being conducted under the guidance of a Management Transition Advisory Group (MTAG) of federal, state and local partners and end users. This approach is designed to inform management actions to maintain or enhance the ecosystem services of marshes and other natural features on state-owned lands; re-evaluate Chesapeake Bay SAV restoration goals; improve existing conservation prioritization tools; and provide relatable, local examples to advance coastal preservation efforts by agencies throughout the state.