ANALYSIS OF GEOMORPHIC CHANGES IN A SOUTHERN NEW JERSEY SALT MARSH DUE TO NATURAL AND ANTHROPOGENIC PROCESSES

Through GIS analyses of lidar and aerial photography datasets, our team will analyze changes in salt marsh geomorphology in the Seven Mile Island Innovation Laboratory (SMIIL) in southern New Jersey. This is a region with high rates of relative sea level rise (4 mm/yr), which threatens the stability of the salt marsh. One of the goals of SMIIL is to study the beneficial use of dredge sediment placements on and adjacent to salt marsh islands as a mitigation strategy. Several placement projects have been conducted in recent years, leading to ongoing changes in island morphology. Orthophotographic imagery (from 2007-2020) will be used to analyze changes in area and movement of the boundaries of the salt marsh islands. We will difference sequential lidar surveys (potentially including terrestrial and/or topobathymetric surveys conducted in 2008, 2011, 2014, 2015, 2017, 2019, 2020, and 2021) to measure volumes erosion and deposition, including through placements of dredge sediment. Our study will identify particularly vulnerable areas of SMIIL that could benefit from anthropogenic interference through sediment deposition and other mitigation strategies.