Topographical Analysis of the 2013 Typhoon Haiyan Storm Surge Flooding by Combining the JMA Storm Surge Model and the FLO-2D Flood Inundation Model

Lea Dasallas,Seungsoo Lee

doi:10.3390/w11010144

Abstract

The floods associated with the effects of an incoming tropical cyclone have an immense effect in the Philippines, especially with respect to agriculture, industry, livelihood, and public safety. Knowledge of how such storm surge flooding can affect the community is therefore of great importance. In this study, the mechanisms behind Typhoon Haiyan’s anomalous storm surge flooding in 2013, which resulted in more than 6300 casualties and 2.86 billion USD worth of damage in the Philippines, were investigated. The Japan Meteorological Agency (JMA) storm surge model and the FLO-2D flood model were used to simulate Typhoon Haiyan’s storm surge height and the extent of inundation, respectively. The storm surge input data were obtained from JMA typhoon data, and the digital terrain models used were gathered from the airborne interferometric synthetic aperture radar data. The model’s accuracy was also validated using field validation data of the extent of the observed storm surge in affected coastal areas. Topographical analysis of the inundated regions showed the effects of coastal shape, elevation, and position relative to the typhoon’s approach angle on storm surge flow depth and velocity. Storm surge maximum velocity appears to increase as the fluid flows to an increasingly elevated area. Observing fluid velocity in a coastal area with uniform storm surge discharge from all directions also showed that flow velocity tends to increase at the center. Greater flood depths were experienced in areas with lower coastal elevation and not directly located at the coast, compared to higher elevation coastal areas. Greater extents of storm surge flooding are expected in coastal areas that have a concave shape, as fluid is more likely to be dispersed when hitting a convex coast. Extents are likewise observed to be greater in coastal regions that are located perpendicular to the direction of the typhoon. The research also validated the option of using a combination of typhoon and flood models to simulate the inundation flooding caused by extreme weather events.

Highlights

The natural hazards generated by a tropical cyclone impose significant threats, especially to coastal communities
Several storm surge models have been developed by atmospheric and coastal researchers. These storm surge models include the Sea Lake and Overland Surges from Hurricanes model by the National Oceanic and Atmospheric Administration (NOAA) and National Hurricane Center [3,4], the Mike21 and Mike Flood models [5] developed by the DHI Water and Environment Corporation, the Delft3D coastal surge model [6] by Deltares, and the
After establishing the reliability of the models that were used, it was necessary to determine why some coastal areas experiences worse storm surge compared to other areas

Summary

Introduction

The natural hazards generated by a tropical cyclone impose significant threats, especially to coastal communities. These hazards, such as rainfall-induced flooding and landslides, and the storm surges generated by the strong winds, have been known to result in substantial loss of life and damage to properties in the Philippines. Modeling storm surges is not as common and well known as flood and debris flow modeling. This is mainly due to the rarity of storm-surge-related hazards compared with the hazards associated with flooding events. These storm surge models include the Sea Lake and Overland Surges from Hurricanes model by the National Oceanic and Atmospheric Administration (NOAA) and National Hurricane Center [3,4], the Mike and Mike Flood models [5] developed by the DHI Water and Environment Corporation, the Delft3D coastal surge model [6] by Deltares, and the

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Conclusion