Computing Water Quality Deterioration Attributed to Anthropogenic Impacts in Dehradun—A Lower Himalayan Region of India

ABSTRACT Water quality is a stern issue in urban areas because it is indispensable for the sustenance of life. The present study aimed to determine the spatial trends with time in water quality attributed to transitioning anthropogenic land‐use/cover in a Himalayan city—Dehradun, India—through the Weighted Arithmetic Water Quality Index (WQI). A total of 36 samples from nine surface aquifers during four seasons were analyzed for physicochemical and biological water quality parameters and compared with standards prescribed by BIS—Bureau of Indian Standards and WHO—World Health Organization. The water quality categorization during the monsoon (good–moderate), post‐monsoon (poor–very poor), and the winter and premonsoon seasons (poor–unfit) reveals the temporal trends. Further, WQI values indicate that 25% of the water samples (urban) were in the very poor–unfit category, 52% in poor (semi‐urban), and 22.2% in good status (rural), with elevated values for Coliform bacteria at all locations. Unsustainable anthropogenic activities, namely, discharge of wastewater, indiscriminate dumping of solid waste, and fecal matter, are the main factors, which have negatively impacted the water quality of these rivulets. Land‐cover analyses from 2002 to 2023 observed an increase in settlement—urban built‐up (+7.5%), cultivated land (+7.5%), and barren land (+4.4%), whereas grassland (−8%), forest (−12%), and water bodies (−0.11%) decreased in terms of area coverage, with a slight decline in land surface temperature regimes attributed to the aerosol optical depth variations. The management of water resources (catchment basin conservation) in the Dehradun region is a major concern pertaining to urban land use planning and the mandate of Sustainable Development Goals (SDGs) 6 and 11.