Abstract
Destruction caused by recent hurricanes on natural and built environment along New York City coastlines emphasize the significance of delineating coastal floodplain and mapping the potential area of inundation followed by coastal floods. Floodplain delineation and appropriate planning in these areas could help mitigate some flood damage. In this study, a geographic information system (GIS) based method is proposed and applied for floodplain delineation in the coastal part of the Bronx River watershed, Bronx, New York City. Extreme water level in recurrence intervals of 2, 5, 10, 25, 50, and 100 years is determined by frequency analysis of the extreme sea levels in the region provided by NOAA (National Oceanic and Atmospheric Administration). To determine coastal floodplain followed by increasing water level, HEC-RAS model is used. The GIS (geographic information system) capabilities are used for illustration of inundated regions. The results of the study show that the extent of floodplain perpendicular to the river direction can be increased by up to 500 ft regarding the water level with 100-year return period. Taking into account these results in determining land use of the floodplain beside the river enables mitigation of the damages associated with coastal flooding caused by extreme water levels.