Application of Geographic Information Systems (GIS) in the Multi Criteria Site Selection of Retention Pond for Urban Rainwater Management

This article aims to determine the criteria needed and to create a map of location suitability for the retention pond site selection with the case study in the city of Medan, the province of North Sumatra, Indonesia. The multi criteria decision analysis (MCDA) based on geographic information system (GIS) was applied to reach this goal. Pairwise comparison (PC) method of analytic hierarchy process (AHP) is used to calculate the weight of each criterion and the weighted linear combination (WLC) method applied to combine the criterion or factor maps. All of the data processing and analysis were completed using IDRISI-Selva software version 17, where the final result was a suitability map. Seven factor maps (i.e. rainfall, runoff, slope, aquifer, distance to channels, distance to river, and land use/land cost) and seven constraint maps (i.e. well, road, strategic area 1, strategic area 2, utilities, railway, land use) are established and involved in this site selection model. The obtained suitability map has four levels of suitability, namely low, moderate, high and very high suitable with an area of 0 ha, 379 ha, 12,778 ha and 1291 ha, respectively. The results of this study can be used as input to decision makers in urban areas, especially in terms of selecting the location of retention ponds to improve their rainwater management performance.