Development of a historic Digital Elevation Model (DEM) and data for a marsh model testbed

Tidal marsh ecosystems provide important ecosystem services, yet they are increasingly vulnerable to degradation and loss due to climate change, sea-level rise, reductions in sediment loading, and other environmental changes. Consequently, there is increasing demand to manage, conserve, and restore marsh ecosystems that are resilient to these environmental changes. Scientists and natural resource managers utilize process-based models to predict how environmental change, including accelerating sea-level rise and engineering interventions, might affect the trajectory of marsh ecosystems under different scenarios. To evaluate the fidelity of contemporary marsh models, there is a critical for systematic retrospective analyses across model ensembles. Dynamic changes in marsh elevation represent a key point of uncertainty in these analyses, necessitating consistent digital elevation models (DEMs) of marsh bathymetry across model simulations. The goal of this work is to develop adjusted, historic DEMs of marsh bathymetry to support a marsh modeling testbed at the Grand Bay National Estuarine Research Reserve in Mississippi and the Plum Island Estuary in Massachusetts. Specific objectives include: (i) synthesizing available geospatial and empirical datasets, in partnership with The Water Institute of the Gulf; (ii) leveraging existing coring data and collecting and dating new marsh sediment cores to date using radioisotopes; (iii) using geospatial modeling to develop adjusted, historic marsh DEMS for both sites; and (iv) contributing to ongoing efforts to develop data libraries and conduct retrospective model analyses.