Simulative analysis of the mitigation effectiveness of Leyte Tide Embankment against coastal flooding under Typhoon Yolanda 2013

Author: Karl Derrick S. Rizabal, Eric C. Cruz, Imee Bren O. Villalba

Presenter: Eric C. Cruz

The Leyte Tide Embankment, also called the TPT (Tacloban-Palo-Tanauan) Tide Embankment, is a coastal infrastructure, now under construction, that was designed to protect Tacloban City and the towns of Palo and Tanauan after the devastating storm surge-induced coastal flooding and severe wind disasters due to Typhoon Yolanda (international name: Haiyan) in November 2013. In order to assess the effectiveness of this engineering intervention, a coastal engineering analysis of the storm surge overtopping safety of this 27.3-km-long tide embankment wall is carried out. This paper presents the methodology of the preliminary coastal engineering analysis based on the storm surge hazard only, i.e. without typhoon waves, in order to understand the level of protection afforded by the infrastructure. 

The embankment alignment and cross-section data are based on published documents by JICA and DPWH, while offshore and local bathymetry and coastal topography data are taken from secondary sources. Meteorological loading is based on the cyclonic surface winds and translating pressure fields of Typhoon Yolanda 2013, while tide loading along open boundaries is based on a harmonic tide predictor. A mesoscale unstructured mesh is used to numerically implement the ADCIRC storm surge model utilizing depth-adaptive finite elements to optimize the mesh. Results of storm tide levels (STL) under T. Yolanda 2013 loading indicate that the entire length of the embankment wall would be overtopped, and that the overtopping duration would be as long as 110 minutes in the southern sections (Palo and Tanauan). While the simulations indicate that the intensity of coastal flooding within these affected areas is modulated by the embankment, these initial results have important ramifications to the design basis of the implemented engineering solution, particularly to the disaster mitigation plans after the embankment is overtopped by a similar Typhoon Yolanda event.

Conference/s:

First National Scientific Conference on Water, 2019 November 7-9

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