Metrics of resilience and recovery in Riding Academy North & South, 2014-2016: Jamaica Bay Unit, Gateway National Recreation Area

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

This report documents an analysis of linear feature displacement, elevation change, and volumetric change over time at Riding Academy North and South, Jamaica Bay Unit of Gateway National Recreation Area. This analysis provides data-driven information regarding the resilience of the beach and dune system along Riding Academy North and South and the ability of the system to recover after storms. The Riding Academy survey sites are an area of interest for their characteristic geomorphologies as well as a functioning natural dune-beach system with 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 Riding Academy survey sites (Psuty et al., 2017). Seasonal survey data spanning from the winter of 2014 to the fall of 2016 were supplemented with LiDAR datasets from August 2010 and November 2012 to monitor the impacts of and recovery from Hurricane Sandy (October 2012). In addition, three storms occurred in 2016 that affected the recovery of Riding Academy survey sites. Riding Academy North and Riding Academy South had variable dune crest position, shoreline position, site elevation, and site volumetric change from 2010 to 2016. From 2010 to 2012, there was volumetric loss in the dune feature, and gain in the beach feature at both Riding Academy North and Riding Academy South. Elevation change between seasonal surveys was variable; the winter surveys showed more loss in both the dune and beach elevation than spring or summer. The net comparison from the first field survey in December 2014 to the last survey in November 2016 showed overall elevation and volumetric gain in the dune and beach features at Riding Academy North. The foredune crest and shoreline features showed a similar temporal pattern of seaward displacement. There was also overall elevation and volumetric gain in the dune and beach features at Riding Academy South, mostly in the central and western facets, with erosion dominating the eastern facet. The foredune crest and shoreline features showed seaward displacement in the western facet, and landward displacement in the eastern facet. Despite volumetric loss along the majority of the site during the 2010 to 2012 period, Riding Academy North and South have shown signs of absorbing disturbances caused by Hurricane Sandy and subsequent storms during the survey period. A persisting beach and dune system at both survey sites was an indication of resilience. Spatial displays of shoreline and foredune linear feature change, elevation change, volumetric change, and associated metrics are presented within the report.

Metrics of resilience and recovery in Riding Academy North & South, 2014-2016: Jamaica Bay Unit, Gateway National Recreation Area

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