HEAVY RAINFALL INDUCED FLOOD AND LANDSLIDE IN BENGKULU, INDONESIA

摘要

Indonesia is one of the countries with a significant number of flood and landslide events induced by heavy rainfall that sustain significant losses. Synthetic Aperture Radar (SAR) images by Sentinel-1 are employed to investigate the impacts of heavy rainfall induces landslide, which has a high temporal resolution and easily accessible. The RGB composite detected flood and landslide areas from Dual-polarimetry by Sentinel-1. In this study, flood and landslide areas in the Bengkulu area in Indonesia were detected by Sentinel-1 data on April 27, 2019. Simultaneously Rainfall data from the Meteorological, Climatological, and Geophysical Agency of Indonesia (BMKG) was analyzed the hourly rainfall and cumulative rainfall to determine the possibility of flooding and landslides in their area. As a result. One of the rainfall observation stations, namely the ARG BP3 Tes, observed cumulative rainfall data, which reaching 5588.8 mm/day, with the highest hourly rainfall is 541.2 mm/hour on April 26, 2019. Google Imagery on May 2, 2019 showed some landslide's locations in the mountainous area. The landslide generates sediment that directly transports to the Batang Simpangaur river and causes the river's bottom shallower than usual conditions, which magnified in Bengkulu flooding.