|Drowning of Developed Coastal Barriers: Investigating the threshold Rates of Sea-Level Rise of the Geological-Human System|
Andrew Ashton (WHOI); Jeff Donnelly (WHOI); Rob Evans (WHOI); Di Jin (WHOI); Hauke Kite-Powell (WHOI)
Coastal barriers, narrow sandy islands or spits found along many of the world's coasts, respond to sea-level rise through a process of landward migration. During storms, overwash and breaching transfer sediment onto the back of the barrier. Over the next century, these barriers face an uncertain future. Rates of sea-level rise already exceed those experienced over the last several thousand years and are predicted to be substantially greater by the end of the century, offering the potential that barriers could drown. Human activities intended to preserve coastal infrastructure, such as building seawalls, constructing groynes, nourishing beaches, stabilizing inlets, or armoring updrift headlands, have accumulated to the point where a new landform, unprecedented in earth's history, has emerged: the "developed barrier." This study addresses the future of developed barriers during accelerated sea-level rise through the development of models that couple natural sediment transport processes with human alterations of the coast. This study seeks answers to two key questions: (1) are there threshold rates of sea-level rise beyond which coastal barriers will drown completely; and (2) will human responses to sea-level rise mitigate or exacerbate the potential for losses of developed barriers across entire systems?
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