Using remote sensing to collect data on the impact of flooding on the built environment in Kerala, India
Here we present research into methodologies for using remote sensing to collect data on the impact of flooding on the built environment, using the case study of the 2018 Kerala, India floods. According to figures published by the Kerala State Disaster Management Authority, the 2018 floods affected over 800,000 houses and damaged over 9,000 km of roads. Methods based on interferometric coherence decrease have proved successful in detecting structural damage in urban areas caused by natural disasters such as typhoons, tsunamis and landslides. In this situation, however, those methods perform less well because they struggle to detect flood impact in non-urban areas which did not have high pre-event coherence and at buildings that were damaged by inundation but did not sustain the type of structural or roof damage that causes coherence decrease. We therefore assess the alternative approach of combining flood and built environment datasets and we compare the results of doing so using existing or routinely-produced datasets versus using datasets processed especially for this application.