Urban areas near coast and estuary can be flooded due to multiple hydrodynamic driving forces such as coastal and riverine floods, high tides, rain fall, and rising sea levels. Due to interaction among the hydrodynamic forcings in coastal urban areas, the resultant flooding and inundation can cause severe damages of urban infrastructure and human casualties. Numerical simulation of multiple coastal and riverine dynamic processes is important to assess the risk and uncertainty of coastal urban floods. It is critical for the simulation models to capture complex topographic features over a storm-impacted region from continental shelf of open oceans, coasts, estuaries, and rivers to urban environments. Those features include flood defense structures (dikes, levees, tide gates, etc.), commercial buildings, residential houses, roads, airports, and vegetated land covers. The inclusion of these topographic features together with regional water bodies requires spatially-varying computational mesh resolutions, which pose challenge to numerical simulation efficiency. This presentation is to present a hindcast simulation of the most hazardous flooding and inundation in the northeastern New Jersey occurred during Hurricane Sandy (2012). The simulation was performed by using a nesting computational approach to reproduce storm surges, waves, and tides in the north Atlantic Ocean and coastal and riverine flooding in the urban areas of the northeastern New Jersey, including Hackensack, Moonachie, and Newark. Dynamic inundation processes were simulated by including fluvial floods from Hackensack and Passaic Rivers. A spatially high resolution mesh was able to capture the flooding process over river banks and through roads and inundating airport. Model validation was achieved by comparing simulation results with the surge tides observed at NOAA tide gauges and USGS Sandy flooding map.
