SEA-LEVEL, STORMS AND LAND LOSS IN CHESAPEAKE BAY DURING THE LAST MILLENNIUM

Rapid shoreline retreat has been linked to the collapse or retreat of many Chesapeake Bay communities during the 20^th century. Many of the coastal communities and infrastructure that remain are threatened by continued erosion, yet the principal climatic driver of this land loss—sea-level rise versus wave erosion—remains unquantified. Here we evaluate the contribution of these forcings to coastal erosion in Chesapeake Bay by comparing historic surveys documenting shoreline retreat with instrumental storm and tide gauge records. We then extend this analysis over the past millennium using proxy based reconstructions of coastal erosion and storm frequency from a sediment core PCT_VC1 (37.748383°,-75.871917°) collected in 15 meters of water from the Pocomoke Channel, eastern Chesapeake Bay. Sediment grab samples from throughout Pocomoke Sound demonstrates a substantial nearshore increase in marsh pollen taxa. Our preliminary data suggests that deposition of these same taxa at our core site increased during the 20^th century, signaling increased coastal erosion, likely in response to accelerating sea-level rise. The frequency of intense storms, inferred from downcore coarse-grained sediment deposits, appears to have had a more minor impact on nearshore erosion during much of the last millennium.