Multi-criteria geospatial analysis of rainwater harvesting potential zones and susceptibility of built-up regions in Hyderabad City, India

This study aimed to develop an integrated framework for the identification of Rainwater Harvesting Potential Zones (RWHPZs) of Hyderabad city in India by using Remote Sensing (RS), Geographic Information System (GIS), and the Analytic Hierarchy Process (AHP) techniques. This framework utilized the various data layers, such as Digital Elevation Model (DEM), slope, Topographic Wetness Index (TWI), Drainage Density (DD), Drainage Network (DN), Land Use/Land Cover (LUCL), and Rainfall as the critical factors in the AHP technique, followed by the Weighted Overlay Analysis. This study’s findings divided the Hyderabad city into five potential (very low, low, moderate, high, very high) zones. The findings were then superimposed with OpenStreetMap building footprints to study the susceptibility of built-up regions to RWHPZ. About 93.73 sq. km is used for buildings out of Hyderabad’s 680.36 sq. km perimeter, and is ideal for rooftop rainwater collection, whereas 586.62 sq. km is good for rainwater collection structures (which even include the water bodies), according to the overlayed map. Build-up regions can still contribute by transforming impermeable surfaces into collecting zones using rooftop rainwater harvesting and storage systems. According to the analysis of the RWHPZ map, the very low potential zone, which makes up to 17.85% of the area without buildings and 18.72% of the built-up area, is best suited for runoff collection. In contrast, the low potential zone, which makes up to 43.98% of the area without buildings and 57.01% of the built-up area, is ideal for rooftop rainwater collection and recharge. While extremely high potential zones, which account for only 7.29% of the land, offer ideal conditions for rainwater harvesting, moderate and high potential zones, which comprise 30.9% of the area, are suitable for implementing efficient rainwater collection solutions.