Tracking changing shorelines of the most dynamic barrier island of eastern North America: Hunting Island, South Carolina, USA

Keywords: historical maps, ghost forest, remote sensing, erosion, groin, sea level
Session Type: Virtual Poster Abstract
Day: Friday
Session Start / End Time: 2/25/2022 05:20 PM (Eastern Time (US & Canada)) - 2/25/2022 06:40 PM (Eastern Time (US & Canada))
Room: Virtual 40

Abstract

Hunting Island (HI), SC, represents arguably the most rapidly landward-eroding (~6m/yr) barrier island on the east coast of North America. With 8km of sandy beach and rarely-preserved mature maritime forests, the mostly undeveloped island and some adjacent saltmarshes comprise the whole of HI State Park. Erosion dynamics on HI are influenced by sea level rise, persistent longshore currents, and strong tidal oscillations through the inlets bracketing the island. Hurricanes have also caused significant changes. The relocation of HI’s lighthouse twice, “ghost” forests of drowned trees, and recent wave-driven destruction of roads and park cabins provide evidence of its highly dynamic shoreline. Proactive efforts to resist beach erosion include dune stabilization, beach augmentation, and several groin installations.

Due to its Civil War importance, HI’s shoreline morphology has been relatively well documented since the mid-1800s, with lower-resolution maps available from the 1700s, and later, aerial photographs and other remotely-sensed imagery. This research, conducted by the faculty and students of a 2021 graduate course, documented spatiotemporal changes in the island’s morphology and erosional patterns. We present evidence of change across a variety of timescales from multicentennial landward retreat, to lingering scars from decades-old lagoon dredging, to groin-related downdrift acceleration of beach erosion that jeopardizes an unusual ocean-fronting lagoon. As a barrier island, HI shelters the landward marshes and mainland, including the city of Beaufort and its harbor, from powerful winds and storm waves. The island deserves further study in order to better predict future changes under warming climates and rising seas.