**The Storm Surge and Sub-Grid Inundation Modeling in New York City during Hurricane Sandy**

#### **Harry V. Wang, Jon Derek Loftis, Zhuo Liu, David Forrest and Joseph Zhang**

**Abstract:** Hurricane Sandy inflicted heavy damage in New York City and the New Jersey coast as the second costliest storm in history. A large-scale, unstructured grid storm tide model, Semiimplicit Eulerian Lagrangian Finite Element (SELFE), was used to hindcast water level variation during Hurricane Sandy in the mid-Atlantic portion of the U.S. East Coast. The model was forced by eight tidal constituents at the model's open boundary, 1500 km away from the coast, and the wind and pressure fields from atmospheric model Regional Atmospheric Modeling System (RAMS) provided by Weatherflow Inc. The comparisons of the modeled storm tide with the NOAA gauge stations from Montauk, NY, Long Island Sound, encompassing New York Harbor, Atlantic City, NJ, to Duck, NC, were in good agreement, with an overall root mean square error and relative error in the order of 15–20 cm and 5%–7%, respectively. Furthermore, using largescale model outputs as the boundary conditions, a separate sub-grid model that incorporates LIDAR data for the major portion of the New York City was also set up to investigate the detailed inundation process. The model results compared favorably with USGS' Hurricane Sandy Mapper database in terms of its timing, local inundation area, and the depth of the flooding water. The street-level inundation with water bypassing the city building was created and the maximum extent of horizontal inundation was calculated, which was within 30 m of the data-derived estimate by USGS.

Reprinted from *J. Mar. Sci. Eng.* Cite as: Wang, H.V.; Loftis, J.D.; Liu, Z.; Forrest, D.; Zhang, J. The Storm Surge and Sub-Grid Inundation Modeling in New York City during Hurricane Sandy. *J. Mar. Sci. Eng.* **2014**, *2*, 226-246.

#### **Abbreviations**

NOAA, National Oceanic and Atmospheric Administration, US Department of Commerce; USGS, U. S. Geological Survey, US Department of the Interior; SLOSH, Sea, Lake and Overland Surges from Hurricanes; ADCIRC, The ADvanced CIRCulation Model; FVCOM, Finite-Volume Coastal Ocean Model; CH3D-IMS, Integrated Modeling System based on CH3D (Curvilinear Hydrodynamic 3D); CEST, Coastal and Estuarine Storm Tide; ECOM-3D, Estuarine Coastal Ocean Model 3D.
