Application of Analytical Hierarchy Process (AHP) to Flood Hazard Management for Makassar City, South Sulawesi-Indonesia

Abstract

A major challenge in flood risk management and assessment is limited data availability because of the cost of collecting and analyzing data. This study project was therefore developed to offer an alternative technique for assessing flood risk. A flood risk assessment was conducted by deploying the analytic hierarchy process (AHP) to build a flood risk model in order to explore and incorporate the perceptions of individual people and communities as its main data sources, where their experiences, knowledge, educational background, and intuitions are considered valuable and accurate information on how to deal with living in a disaster prone area. The developed model was built with four main hierarchy levels in order to capture the flood hazard probabilities, their consequences, and alternative actions for dealing with floods. The model was applied in Makassar City as a case study, where the relative flood risk was measured for each of four proposed zones by eliciting six respondent groups' (expert, institutional, zones A, B, C, and D) judgments on pairwise comparisons of each component in the model. The model shows that the average relative probability of flood to no flood occurrence is 59.0%; among the proposed zones, zone A has the highest average relative flood probability, which is 0.175, or 17.5%; the most likely impact to occur during the flood is from dirt and debris carried by the flood and leading to the need for "house cleaning"; and flood control is the most favorable alternative action for the respondents, with a priority level of 0.306, or 30.6%. Furthermore, these results show the model's ability to incorporate people's opinions into flood assessment, as the public opinions collected showed high consistency in how they measured the flood risk in Makassar City and high levels of detail in assessing the flood risk in each zone, as well as providing several alternative actions.