HURRICANE SANDY STORM SURGE DAMAGE AND THE LEGACY OF DEVELOPMENT ON HISTORICAL COASTAL MARSHES

Human population increases and coastal development have increased the risk from coastal hazards and also altered natural habitats. This increased risk was unfortunately clearly illustrated by the coastal flooding from Hurricane Sandy in 2012. This study examined historical topographic maps from the late 19^th and early 20^th century (1883-1918) from coastal New Jersey and Delaware to determine modern coastal development on historic submerged marshland. Twelve 15-minute USGS topographic maps were georeferenced into a geographic information system (GIS; ArcMap, ESRI v. 10.0) so that the maps could be analyzed. The historical submerged marshes were then digitized for each map, creating polygon shapefiles. These shapefiles of historical submerged marshes were then compared to modern road networks and urbanized areas. The modern roads were used as a proxy for human activity and are a measure of how much human population and development has changed since the historical topographic maps. Over 1200 km of modern roads in New Jersey alone were constructed on former submerged marshes, greatly increasing our risks from coastal flooding. The development pattern was generally stronger in southern New Jersey, with the Atlantic City quadrangle having 245 km of roads built on historical marshes but Asbury Park (in northern NJ) only having 21 km. There was a close correlation between these historical marshes and the storm surge flooding from Hurricane Sandy in 2012, showing that historical land use changes are still affecting us today. This research could guide future hazard mitigation efforts and inform decisions about coastal land use, by predicting where future storm surges may go.