Siting of Rainwater Harvesting Potential Sites in Arid or Semi-arid Watersheds Using GIS-based Techniques

Abstract

Rainwater harvesting (RWH) has emerged as one of the efficient strategies to augment surface and groundwater sources to meet water resource demands. The aim of this study is to present a methodology for siting RWH areas and selecting appropriate RWH structures in a watershed using Geographic Information Systems (GIS) and Remote Sensing (RS) based multi-criteria analysis. Derived thematic layers such as drainage density, slope, road network, runoff potential, distance to streams, and distance to built-up areas were used to identify suitable areas for RWH. The Weighted Linear Combination (WLC) technique was used in combination with the Boolean approach in a GIS environment. Normalized weights assigned to thematic layers and features were tested for consistency using the consistency ratio in Analytical Hierarchy Process. The study area can be divided into three categories of suitability, i.e.: (i) Most suitable with 26% coverage (167 km2); (ii) moderately suitable with 30% coverage; and (iii) least suitable with 12.6% coverage (80 km2) of the study area. Suitable RWH and artificial recharge structures were identified based on identified zones. It was found that 11 check dams could be implemented in the study area and 3 percolation tanks along streams and on the ground. This cost-effective and low data-intensive methodology presented can be replicated by relevant stakeholders in arid regions to adopt RWH as an effective strategy to address growing water shortages.