This study was carried out to assess the overall water quality and identify major variables affecting the deep groundwater quality in Kathmandu Valley, Nepal. Forty-two deep wells were sampled during pre-monsoon and monsoon seasons in 2007 and analyzed for the major physicochemical variables. The water quality variables such as NH +4-N, Fe, Pb, As, and Cd at most of the sampling locations exceeded the World Health Organization guideline levels for drinking water. Multivariate statistical techniques such as factor analysis and cluster analysis were applied to identify the major factors (variables) corresponding to the different source of variation in deep groundwater quality. Factor analysis identified six major factors explaining 74.77% of the total variance in water quality; and the major variations are related with the degree of groundwater mineralization, decomposition of organic matter, and reduction of groundwater environment. The water quality of deep groundwater is influenced by the natural hydro-geochemical environment. The wells are broadly divided into two major groups based on similar groundwater characteristics using cluster analysis. Results show that water quality of deep groundwater does not vary significantly as a function of season.
Groundwater resources of Kathmandu Valley in Nepal are under immense pressure from multiple stresses, including climate change. Due to over-extraction, groundwater resources are depleting, leading to social, environmental, and economic problems. Climate change might add additional pressure by altering groundwater recharge rates and availability [...]