MULTI-SCENARIO SEA LEVEL RISE MODELING OF ECOLOGICAL VULNERABILITY IN THE MANOKIN WATERSHED, MARYLAND’S EASTERN SHORE

Abstract

Sea level rise (SLR) is a direct and measurable impact of climate variability, posing substantial risks to coastal ecosystems. This study employes NOAA’s Sea Level Rise Viewer to evaluate potential ecological change under four SLR scenarios (1, 2, 4, and 6 ft) within the Manokin Watershed, Somerset County, Maryland. The watershed is a low-lying, highly tidal system encompassing approximately 58,000 acres, nearly half of which consists of tidal and nontidal wetlands, and it experiences one of the highest land subsidence rates on the Delmarva Peninsula (>3 mm yr⁻¹). Spatial analysis of NOAA projections, integrated with ecological assessments from the University of Maryland Center for Environmental Science, the Chesapeake Bay Program, and the National Wildlife Federation, reveals progressive and nonlinear habitat loss across scenarios. Under a near-term scenario (~1 ft by mid-century), mean habitat retention remains near 84%, with tidal flats and salt marshes most affected. An intermediate scenario (~2 ft) reduces retention to approximately 69%, accelerating brackish marsh loss and coastal squeeze. High-end projections (4–6 ft) result in transformative landscape change, with up to 95% cumulative wetland loss by 2100. Vulnerable resources include the American Black Duck, anadromous fishes, blue crab, and the 16,400 acre Manokin River Oyster Sanctuary. Results identify priority conservation areas and underscore the need for spatially explicit, multi-scenario planning for Eastern Shore watersheds.