GIS-Based site selection for Rainwater Harvesting (RWH) systems in Davao City Philippines

Abstract

The looming water crisis and environmental problems aggravated by climate change, such as flooding, the implementation of RWH systems for different applications is deemed an effective solution, especially for areas with abundant rainfall, such as Davao City. This study utilized QGIS to map suitable site for open area rainwater harvesting (RWH) systems in Davao City, Philippines. This study aimed to identify potential location sites for RWH systems in Davao City by producing suitability maps using weighted overlay analysis. The Weighted Overlay Analysis was implemented to produce a suitability map based on the assigned weights of datasets to influence the overall RWH suitability. The datasets employed include slope, rainfall, land use, soil type, and lineament density. Findings show that the very highly suitable areas for RWH systems are located mostly in the districts of Marilog, Baguio, Calinan, Paquibato and some parts of Tugbok. In addition to the same districts, Calinan, and Tugbok have highly suitable areas for the RWH system. Unsuitable areas, or areas that were not recommended to implement RWH systems were concentrated in the district of Agdao, Buhangin, Bunawan, and Poblacion, where urban areas are located. The resulting suitability map can benefit the local authorities and planners in implementing RWH systems for the development of city’s agriculture in water resource conservation, and flood management, supporting sustainable development and climate resilience in Davao City.