ANALISIS SPASIAL DAMPAK BANJIR BANDANG MENGGUNAKAN GOOGLE EARTH ENGINE DI NAGARI MANINJAU, KEC. TANJUNG RAYA, KAB. AGAM

Abstract

The objectives of this research are: 1) analysis the distribution of flash flood areas based on slope and elevation in Nagari Maninjau using Google Earth Engine (GEE); 2) analysis the impact of flooding on physical and social aspects, including agricultural land and infrastructure, using Google Earth Engine (GEE). This research uses a quantitative approach method with spatial analysis based on Remote Sensing and the use of cloud computing technology through Google Earth Engine. The data used included Sentinel-1 Synthetic Aperture Radar (SAR) images with VV polarization before and after the flash flood event, and National Development Planning Agency (DEMNAS) data through backscatter change detection analysis.The results showed that the flash flood area in Nagari Maninjau reached 50.42 hectares, with an overall accuracy of 94.00% and a Kappa coefficient of 0.8717, indicating a strong level of classification suitability. Flooding was dominated by areas with slopes <15% and elevations <550 meters above sea level, causing damage to agricultural land and infrastructure located near the flood flow path. The results of this study indicate that topographic characteristics, particularly low elevation, gentle slopes as sedimentation zones, and proximity to river networks, have a significant influence on flash flood distribution patterns.