Development of flood risk map at Kuantan using geographical information system

Abstract

The purpose of this study is to develop the flood risk map in Kuantan. The heavy prolonged rainfall in Kuantan has showed an increasing flood disaster over a year. Geographical Information system (GIS) is integrated with AHP is used to generate the potential flood risk area. Flood map was develop by applying data Digital Elevation Model (DEM) and Landsat 8 download from United States Geological Survey (USGS) to generate the slope map and land use map. Soil type map was obtained from Department of Survey and Mapping (JUPEM) and rainfall intensity data from Department of Irrigation and Drainage (DID). Rainfall distribution map in study area was generated in ArcGIS software using Inverse Distance Weighted (IDW) interpolation method. The spatial analysis and AHP analysis was used to score and compute weights of each criteria. Score for each criteria based on judgement to the parameter risk level against flooding. Using AHP, the percentage derived from the parameters were land use type is 41.55%, slope 28.95%, rainfall 16.93% and soil type is 12.58%. The value of consistency ratio is 6.9% was acceptable and indicate the judgement for each parameter is consistent. Flood risk areas were generating using flood risk index calculation. The result shows that, land use change, slope degree, rainfall intensity and soil type have significant influences on the flood mapping. The flood risk map using AHP was matched to an actual flood mapping developed by DID in determining potential location of flooding.