BEACH MORPHODYNAMIC RESPONSE TO A 5-DAY SUMMERTIME NOR'EASTER AT CAPE CANAVERAL, FLORIDA

Persistent storm events can initiate changes to local sediment supply and beach morphology. To examine the response of the Cape Canaveral, FL shoreline to tropical and extra-tropical storms, a campaign of monthly beach surveys was initiated in May 2009 to document short-term changes in beach morphodynamic and mean-high-water (MHW) shoreline position. This project is being conducted in conjunction with the examination of shoreline position proxies derived from aerial photographs dating to 1943 and collected with sub-decadal frequency. Cape Canaveral is a large cuspate foreland along the U.S. East Coast affected by both tropical cyclones and Nor'easters storms, each with a unique weather/wave pattern distribution. Surveys were conducted along a 12 km portion of the coast at the Kennedy Space Center (KSC) using a kinematic GPS system mounted on a trailer. Data was collected at 0.5 m intervals using multiple (8-12) along-shore transects, following slope breaks. Seven surveys were conducted from May to August, during which a persistent 5 day Nor'easter erosion event occurred (May 18 – 23) with an average offshore wave height of 3.25 m and a maximum wave height of 5.75 m. A pre-storm survey was collected 12 days prior to the storm (May 6) followed by a post-storm survey collected on May 24. Subsequent surveys were conducted on a full-moon cycle starting in June 2009. Dean et al. (1998) examined shoreline change along Cape Canaveral from 1875 to 1993, and noted a sinusoidal pattern of erosion and accretion intensifying southward along the cape. On the northern border of KSC in an area with little decadal change, the storm produced little horizontal change in the position of the MHW line (<6 m erosion), with a post-storm recovery of +2.5 m seaward of pre-storm conditions. Areas of historical erosion, in the central portion of the study area experienced notable change in shoreline position from the storm (14 m of retreat), but the post-storm shoreline was only 1 m seaward of the pre-storm condition. In an area of historical accretion at False Cape, the storm caused 4 m of retreat followed by nearly 14 m of recovery, seaward of pre-storm position. Ongoing monthly GPS surveys will track how short-term changes in MHW position relate to decadal changes observed from aerial photographs to determine if the sinusoidal pattern of erosion and deposition is a persistent or dynamically evolving feature of the cape.