The Effect of Hurricane Sandy on New Jersey Atlantic Coastal Marshes Evaluated with Satellite Imagery

Abstract

Hurricane Sandy, one of several large extratropical hurricanes to impact New Jersey since 1900, produced some of the most extensive coastal destruction within the last fifty years. Though the damage to barrier islands from Sandy has been well-documented, the effect of Sandy on the New Jersey coastal marshes has received little attention. The objective of this analysis, based on twenty Landsat Thematic Mapper (TM) data sets collected between 1984 and 2011 as well as three Landsat 8 Operational Land Imager (OLI) images collected between 2013 and 2014 was to determine the effect of Hurricane Sandy on the New Jersey Atlantic coastal marshes. Image processing was performed using ENVI (Environment for Visualizing Images) image analysis software with the NDX model (Rogers and Kearney, 2004). The study area was limited to the marshes located in Landsat Path 14 and Rows 32 and 33 which are the northern and southern parts of New Jersey. Validation was achieved through field work (visual estimation of vegetation density and cover) and through a marsh vegetation biomass study at five locations. Two Spot 5 data sets, covering the study area, but with a 10 m spatial resolution were used to estimate land loss between October 13, 2012 (before Sandy) and December 30, 2012 (after Sandy and after vegetation senescence occurred). Results support the conclusion that the marshland area was stable between 1984 and 2006 with only minor inter-annual variation, but has decreased steadily in the density of vegetation coverage since 2007 from different impacts including Hurricane Sandy. Hurricane Sandy caused the greatest damage to low-lying marshes located on islands close to where landfall occurred.