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UAS based 3D shoreline change detection of Jupiter Inlet Lighthouse ONA after Hurricane Irma

ABSTRACT The shoreline along the Jupiter Inlet Lighthouse Outstanding Natural Area (ONA) located in Jupiter, FL, USA, has been impacted by a variety of natural and anthropogenic factors over the years. This has resulted in significant erosion of the ONA’s shoreline, with an estimated retreat of up to 23 m over the last 50 years. Storm events, such as recent hurricanes Matthew (2016) and Irma (2017) contribute to the increase in the rate of shoreline retreat. The higher wind speed and storm surge affected the beach topography by transporting significant amounts of sand into the waterways and away from the site. The purpose of this research is to quantify the shoreline retreat at the Jupiter Inlet Lighthouse ONA caused by Hurricane Irma using Unmanned Aerial Systems (UAS)-based photogrammetry. The historical coastlines represented on aerial photography dating back to 1953 were used to analyse the rate of long-term change and isolate the impact due to Hurricane Irma. Short-term change rate of shoreline and volume change of beach topography was performed using transect-based spatial analysis of pre- and post-hurricane UAS data. The case study reveals that recent hurricane events increased the annual shoreline change rate to more than three times. Further, the volume of sand that has eroded due to Hurricane Irma was determined to be 2.8 hectares.