Characterizing storm response and recovery using the beach change envelope: Fire Island, New York

Abstract

Hurricane Sandy at Fire Island, New York presented unique challenges in the quantification of storm impacts using traditional metrics of coastal change, wherein measured changes (shoreline, dune crest, and volume change) did not fully reflect the substantial changes in sediment redistribution following the storm. We used a time series of beach profile data at Fire Island, New York to define a new contour-based morphologic change metric, the Beach Change Envelope (BCE). The BCE quantifies changes to the upper portion of the beach likely to sustain measurable impacts from storm waves and capture a variety of storm and post-storm beach states. We evaluated the ability of the BCE to characterize cycles of beach change by relating it to a conceptual beach recovery regime, and demonstrated that BCE width and BCE height from the profile time series correlate well with established stages of recovery. We also investigated additional applications of this metric to capture impacts from storms and human modification by applying it to several post-storm historical datasets in which impacts varied considerably; Nor'Ida (2009), Hurricane Irene (2011), Hurricane Sandy (2012), and a 2009 community replenishment. In each case, the BCE captured distinctive upper beach morphologic change characteristic of these different beach building and erosional events. Analysis of the beach state at multiple profile locations showed spatial trends in recovery consistent with recent morphologic island evolution, which other studies have linked with sediment availability and the geologic framework. Ultimately we demonstrate a new way of more effectively characterizing beach response and recovery cycles to evaluate change along sandy coasts.Published by Elsevier B.V.

Beach recovery from extreme storm activity during the 2013–14 winter along the Atlantic coast of Europe

“…A phase of ‘recovery’ towards pre‐storm sediment volume is then a natural morphodynamic response to this depleted state (Brenner et al. ). Because the rates of recovery depend on the magnitude of the storm‐induced changes, the subsequent hydrodynamic conditions, sediment availability and geological setting, predicting the time until full recovery is achieved (if ever) is challenging.…”

“…Sand and gravel beaches may undergo dramatic erosion and recession during sequences of extreme storm wave events (Ferreira, 2006), leaving them in a state of morphological disequilibrium. A phase of 'recovery' towards pre-storm sediment volume is then a natural morphodynamic response to this depleted state (Brenner et al, 2018). Because the rates of recovery depend on the magnitude of the storm-induced changes, the subsequent hydrodynamic conditions, sediment availability and geological setting, predicting the time until full recovery is achieved (if ever) is challenging.…”

Deer do not affect short‐term rates of vegetation recovery in overwash fans on Fire Island after Hurricane Sandy

“…Disraeli () found significantly lower concentrations of chlorophyll in A. breviligulata plants where burial was minimal (e.g., 2.5‐cm) than in areas where burial was great (e.g., 32.5‐cm), and changes in chlorophyll increased exponentially with increases in burial. The presence of budding foredunes on the ocean‐side of overwash fans reduces the amount of sand reaching farther inland (Brenner et al, ; Kilheffer, ; Maun, ), potentially contributing to reduced vigor of A. breviligulata in our study. Because NDVI calculates productivity based upon greenness of imagery pixels, a decrease in this productivity index indicates less greenness, or less chlorophyll, in A. breviligulata in our sites as foredunes continue to limit sand movement inland (Kilheffer, ).…”

Hurricane Sandy and engineered response created habitat for a threatened shorebird

“…We believe two years before the storm was an appropriate sample of pre-hurricane conditions because there were no major overwashing events on the islands between 2010 and Hurricane Sandy. Hurricane Irene hit Fire Island in August 2011 and impacted the island with steady winds and moderate wave heights; however, the storm transferred sand from the foreshore to the upper beach and near-dune regions, resulting in a beachfront elevation shift rather than dune overwash (Brenner et al 2018). Indeed, our post-Hurricane Sandy estimates may underestimate the amount of suitable habitat created by the storm because overwashes were manipulated by engineering between 2012 and 2015 and vegetative succession occurred.…”

“…Hurricane Irene hit Fire Island in August 2011 and impacted the island with steady winds and moderate wave heights; however, the storm transferred sand from the foreshore to the upper beach and near-dune regions, resulting in a beachfront elevation shift rather than dune overwash (Brenner et al 2018). Our model assessed selection two years prior to the storm and three years after because we were limited by nest data and imagery during 2011, 2013, and 2014.…”