Flood Mapping and Damage Assessment using GIS Tools: A Case Study on Before and After-Typhoon Events in Camarines Sur, Bicol Region, Philippines from September to December 2020
The Philippines, an archipelagic sovereign country in Southeast Asia, is one of several nations most often affected by calamities and severe weather such as typhoons. Camarines Sur is one of the provinces in the country that is most prone to disasters. It is vulnerable to tropical cyclones coming from the Pacific Ocean because of its geophysical location. For the first time in several years, it witnessed a typhoon parade in which two powerful tropical cyclones successively struck the province with torrential rains, floods, and landslides.
The study focuses on floods triggered by Super Typhoon Rolly (TY Goni) and Typhoon Ulysses (TY Vamco) between October and November 2020 in Camarines Sur. The production of GIS maps used several datasets of Google Earth Engine. The data selection and pre-processing began with designating the study area and timeline by generating GEE codes. After the selection process, three distinct approaches were conducted. It includes the map evaluation and site analysis on spatial parameters and their correlation to the flooding event. Finally, evaluation for the previous maps has been further addressed and accomplished.
The study of tree losses over the last two decades, the current slope, the existing land cover, and the precipitation in the province of Camarines Sur showed a strong correlation with the flooding events between September and December 2020. It also concluded that GIS is useful in quickly generating maps that can provide necessary information for complete mapping of flood hazards, damage assessment, and emergency response planning.