Acid Sensitivity of Three Large Nepalese Catchments: Case Study of Bhote Kosi, Everest and Langtang

One hundred and fifty-eight stream sites were selected on the basis of their catchment characteristics (i.e. bedrock and land use) in the Bhote Kosi, Everest and Langtang catchments of Nepal. Spot samples of these streams were collected during two post-monsoon periods in 1998 and 1999 and analysed for alkalinity and major ion chemistry. A reconnaissance study (Nov–Dec 1998) sampled a subset of thirty-six streams, and a subsequent survey (Sept–Oct 1999) sampled all one hundred and fifty-eight streams. Of these, two (5%) streams were found to be sensitive to acidification on the basis of their alkalinity in 1998, compared with 31 streams (20%) in 1999.