Spatial variations in water quality of river Ganga with respect to land uses in Varanasi

Water quality of a river is a function of surrounding environment and land use due to its connectivity with land, resulting in pollutants finding their way through land. This necessitates a spatially explicit study of river ecology. The paper presents a pioneer study to establish and explore the linkage between land use and water quality of river Ganga in Varanasi district. The land use land cover (LULC) map of 20 km of river stretch for buffer radii of 1000 m in Varanasi revealed that riparian vegetation is negligible in the district. The hierarchical cluster analysis of LULC data suggested that there are two major land use categories, viz., urban and agriculture. The land use wise principal component analysis (PCA) suggested that urbanized areas are major contributor of metals, whereas agricultural land contributes organic matter into the river. The Spearman correlation study revealed that with rising urbanization, the pollutant load into the river increased compared to that from agricultural land use. The statistical analysis of the data clearly concluded that water quality of river Ganga at Varanasi was a function of adjacent land use. The study provides an insight anticipating the Indian government to embrace the relationship of land use to river water quality while formulating policies for the upcoming River Regulation Zone.