Study of coastal flooding in Kupang, East Nusa Tenggara due to Tropical Cyclone Frances (case study April 27th - 30th 2017)

Abstract

Storm tide is one of the major natural hazard that can be endangered property and residents around the coastal region. A storm tide flooding has been occurred in Kupang, East Nusa Tenggara (NTT) on April 28th 2017 during the appearance of Tropical Cyclone Frances. The aim of this paper is to evaluate the coastal flooding events due to cyclone in order to develop the mitigation strategies in case of similar events in the future. The data from cyclone, such as the track and phase, were shown to see the cyclone stage and its impact to the changes of the waters on the coast of NTT. Three-hourly numerical hindcast of significant wave height (Hs) and primary swell from Indonesian Agency for Meteorology Climatology and Geophysics (BMKG) were used to analyze the waters condition of NTT area. The hindcast was modelled using GrADS with a resolution of 0.125° x 0.125° which has been operationalized by BMKG. Meanwhile, the sea level anomaly from AVISO Satellite Altimetry Data was used to examine the variation of regional sea level variation during the flooding occurrence. From the processing of several data and the analysis, we get that the significant wave and the swell have reaches 6 m high in on the peak of the cyclone event with the sea level anomaly is 10 - 15 cm. Thus, we conclude that this event was occurring because of the swell assisted with the strong steady wind, where the energy could transported the waters up into the mainland.