Author(s): Gallien; Schubert; Sanders

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Keywords: No Keywords

Abstract: Flooding of coastal lowlands occurs in California with the coincidence of high tides and winter storms. This study addresses the predictability of flood inundation in an urbanized setting where embankments and other flood control facilities (e.g., tide gates and pumps) are in use. A two-dimensional (2D) shallow-water model with a robust wetting and drying algorithm is applied to simulate tidal dynamics, embankment overtopping and overland flow at Newport Harbor, California. The terrain description is based on a Light Detection and Ranging (Li DAR) survey of topography, harbor bathymetry data and coastal bathymetry data. Extreme high tides on December 12,2008 and January 10,2005 caused minor and major flooding, respectively, and serve to validate the model. Flood extents were mapped based on field observations and photographs, and compared to model predictions. Results show the model accurately predicts the minor flooding scenario, but major flooding is more difficult to predict. Factors such as flood wall leakage, errors in wall heights and routing through storm sewers contribute to accuracy loss. Further, results show that simplistic flood inundation predictions, based only on the relative height of terrain and sea levels, overestimates flood extent.

DOI:

Year: 2009