Metrics of resilience and recovery in West Pond South, 2014-2016: Jamaica Bay Unit, Gateway National Recreation Area

Psuty, Norbert; Patel, Monica; Ames, Katherine; Habeck, Andrea; Haussner, Elizabeth; Schmelz, William; Butler, Kelly; Greenberg, Joshua

This report documents an analysis of linear feature displacement, elevation change, and volumetric change over time at the West Pond South study site, Jamaica Bay Unit, Gateway National Recreation Area. This analysis provides data-driven information regarding the resilience of the beach and dune system along West Pond South and the ability of the system to recover after storms. The West Pond South survey site is an area of interest due to the adjacent breach, formed during Hurricane Sandy, and limited anthropogenic influence. The Jamaica Bay resilience project uses the Coastal Landform Elevation Model Protocol to create a three-dimensional subaerial topography model of the West Pond South survey site (Psuty et al., 2017). Seasonal survey data spanning from the winter of 2014 to the summer of 2016 were supplemented with LiDAR datasets from August 2010 and July 2013 to monitor the impacts of and recovery from Hurricane Sandy (October 2012). During the 2010-2013 period, there was landward displacement of the foredune crest position and shoreline position, as well as volumetric loss in the dune and beach features, due to major storms during this time period. Within this period, a breach was formed to the east of the site during Hurricane Sandy that remained open through the August 2016 survey. The foredune crest position was relatively stable throughout the survey period with minor changes in position, except for the eastern margin of the site where the scarp present on the profile was consistently displaced inland. Between seasonal surveys, the shoreline position also was displaced inland in the eastern margin near the breach at West Pond. Elevation change between seasonal surveys was variable, the winter surveys showed more loss in both the dune and beach elevation than the spring or summer surveys. The net comparison from the first field survey in December 2014 to the last survey in August 2016 showed that foredune crest and shoreline features shifted landward east of the beach node and seaward in the western facet. The net comparison of topographic surveys showed elevation and volumetric loss in the eastern and western facets with gain in the center of the site. Despite volumetric loss along the majority of the site, West Pond South showed signs of absorbing disturbances caused by Hurricane Sandy and a persisting beach and dune system, an indication of resilience. However, the breach did not close during the survey period and erosion persisted in the eastern end of the site near the breach. Spatial displays of elevation change, volumetric change, shoreline and foredune linear feature change, and associated metrics are presented within this report.

Metrics of resilience and recovery in West Pond South, 2014-2016: Jamaica Bay Unit, Gateway National Recreation Area

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