HYDROLOGICAL AND ENVIRONMENTAL ASSESMENT OF AN URBAN STORMWATER SYSTEM

Abstract

Over recent decades, the unprecedented pace of global urbanization has ushered in a multitude of challenges, with rapid drainage of stormwater emerging as a complex issue in burgeoning urban areas. This thesis addresses the imperative to evaluate the viability of metropolitan town stormwater drainage systems and seeks solutions to the challenges posed by urbanization. The Government of India's sub-committee for the development of "National Sustainable Habitat Parameters on Urban Stormwater Management" introduces key indices crucial for the planning, execution, and maintenance of sustainable stormwater management policies. Indices such as the Natural Drainage System Index (NDSI), Drainage Coverage Index (DCI), Permeability Index (PI), Water Bodies Rejuvenation Index (WBRI), Water Body Vulnerability Index (WBVI), Water Logging Index (WLI), Area Vulnerability Index (AWI), Stormwater Discharge Quality Index (SWDQI), and Rainfall Intensity Index (RII) were evaluated for tier-I (Delhi, Mumbai, and Chennai) and tier-II (Varanasi, Chandigarh, Roorkee) cities in India. The study employed the Analytical Hierarchy Process to rank these indices and derived an "Overall Sustainability Index" for each city, offering a nuanced understanding of their stormwater management policies. In tandem, the investigation shifts its focus to the sub-tropical urban area of Roorkee, conducting rainwater quality studies from 2016 to 2019. Results indicate alkaline precipitation events dominated by Ca2+ and HCO3-. Principal Component Analysis (PCA) and trajectory analysis shed light on ion sources and temporal variability, while the study hypothesizes anthropogenic contributions to sulphates and nitrates.