Assessment and Optimization of Rainwater Harvesting Potential for Urban Sustainability: A Case of Lahore

Abstract

This study employs a multi-criteria decision analysis method utilizing Geographic Information System (GIS) to pinpoint appropriate locations for rainwater harvesting (RWH) structures, to fulfill water demand in Lahore, Pakistan. Data from satellite imagery, soil composition, climate, and digital elevation models (DEM) were integrated into GIS layers and amalgamated to establish a ranking system. This ranking system was then employed to identify suitable areas for rainwater harvesting. Thematic layers, encompassing variables such as rainfall, land use/land cover, soil type, slope, runoff depth, drainage density, and stream order, were combined into a comprehensive overlay, resulting in a map delineating RWH suitability. The outcomes revealed that based on Average Annual Rainfall, 1.44% of the study area is classified as 'very highly suitable,' while 5.67% is designated as 'highly suitable.' Conversely, 24.54% of the region is labeled as 'moderately suitable.' Additionally, 65.44% of the region, situated in the east and southeast, exhibits 'low suitability,' and 2.91% is deemed 'unsuitable.' The findings of this research are poised to foster the broader adoption of RWH in the Lahore region to meet water demands. Furthermore, the developed methodology holds adaptability for implementation in other regions or countries.