Identifying suitable sites for rainwater harvesting using GIS & Multi – Criteria Decision Making techniques in Badghis Province of Afghanistan

Abstract

In Afghanistan, about 1/3 (12.5 mln) of the total population have no access to stable water supplies such as groundwater extraction, stream flow diversion, and reservoir storage. In areas with limited water sources, rainwater harvesting (RWH) can improve the availability of potable water. Due to RWH flexibility and applying different criteria, it can be used in various settings, making RWH a viable option for local communities. Within this study, suitable RWH sites were identified based on modern technological approaches (GIS and Multi-Criteria Decision Making (MCDM)) considering different biophysical criteria selected according to the requirements of the target area environment. The Analytical Hierarchy Process (AHP), Weighted Linear Combination (WLC) Model and hydrology tools were used as MCDM and GIS-based decisions, respectively. The proposed methodology was implemented in the target area of 11,772 km2. The obtained land suitability map was divided into five (5) RWH zones: highly suitable (7.84% of the total area), suitable (21.85%), moderately suitable (31.15%), marginally suitable (27.85%), and not suitable (11.31%). The research results show that highly suitable and suitable sites (3,495.47 km2) are located in mountainous zones with good elevation potential, proper valley shapes, and large catchment areas. RWH practices in these areas can be considered as renewable and sustainable alternatives to water demand saturation. In addition to being a solution in terms of providing water to water-scarce areas, RWH installations represent a good climate change response and water resource management means.