IDENTIFIKASI KERENTANAN BANJIR BANDANG MENGGUNAKAN METODE AHP (ANALYTICAL HIERARCHY PROCESS) BERBASIS SIG DI SUB DAS AIR MULAK, KABUPATEN LAHAT (Identification of Flash Flood Vulnerability Using GIS-Based AHP (Analytical Hierarchy Process) Method in Air Mulak Sub-watershed, Lahat Regency)

Abstract

The high rainfall for a long time resulted in flash floods that hit three villages in Lahat Regency, submerged dozens of residents' houses, damaged several public facilities, and cut off-road access. From this incident, spatial information is needed related to areas prone to flash floods so that the negative impacts can be minimized. This study aims to identify the vulnerability of flash floods in the Air Mulak Watershed. This research uses the AHP (Analytical Hierarchy Process) method for rational decision-making of all parameters, integrated with GIS (Geographical Information System) applications. The results of the consistency test for all parameters, the CR value of 0.97% is smaller than 10% and is considered consistent. The results of scoring all parameters are then overlaid by giving weight to each parameter, and it can be seen that the distribution of flash flood susceptibility in Air Mulak Sub-Watershed with a very high percentage of 0.20%, high class of 4.75%, moderate class of 15.78%, low at 43.50%, and very low at 35.78%. The results showed that the parameters that greatly affect flash flooding in the Air Mulak Sub-Watershed are altitude, river density, slope, and distance from the river because the area is where water accumulates from upstream of the river when it rains with high intensity.