spatial analysis on the location of potential danger of flooding in Regency of Donggala using Analytical Hierarchy Process (AHP)

Abstract

The research on the location of potential danger of flooding using spatial analysis was conducted in Regency of Donggala, Central Sulawesi Province. The purposes of this study are to determine the causes of flooding by using Analytical Hierarchy Process (AHP) and to map the flood potential of hazard areas using spatial analysis. This study used six factors causing flooding, namely watershed characteristics, slope, soil type, land cover and use, flow accumulation, and the level of precipitation. In this study, the Regency of Donggala divided into two main area: the north and south based on differences in physical conditions of each region. Based on the weighing results using the AHP for northern part of Donggala, the percetage of factors causing flooding were characteristic of the watershed by weight of 45.28%, land use 23.91%, flow accumulation 14.88%, slope 8.44%, rate of rainfall 4.75% and soil type 2.74%. On the other hand, the factors causing flooding in southern part of Donggala were land use reached 46.09%, watershed characteristics 23.59%, flow accumulation 12.65%, slope 8.91%, precipitation levels 5.21%, and types of soil 3.54%. These factors then overlaid and used to calculate the value of danger. Based on the spatial analysis, the potential locations of flooding in Donggala were classified into potentially vulnerable in the area of 44321.39 hectares, potentially mid-vulnerable being 144099.75 hectares and areas that are not potentially flood being 281709.49 hectares. The flood in Donggala is mostly influenced by a broad watershed characteristics and the use of public land which cause the increase of accumulation flow in the rainy season.

Keywords:spatial analysis, AHP, flood hazards.