Worldwide, water availability will be a key issue in the 21st century. Per capita water availability is projected to fall from 6600 to 4800 m 3 between 2000 and 2025 because of uneven distribution of water resources. However, most of the world's population will have below 1700 m 3 per capita (Cosgrove and Rijsberman 2000). Mountains, in particular, are of great importance because more than half of humanity relies on freshwater that originates from mountains (Liniger et al 1998; Viviroli 2001). The rising demand for water from growing populations, climate change affecting water supplies , and increased uncertainty in relation to natural hazards (eg, increased occurrence of landslides, glacial lake outburst floods) are some of the reasons for future concern (Kundzewicz et al 2001). In the context of the Hindu Kush-Himalayan (HKH) region with its pronounced monsoonal climate, the following dual concern can be demonstrated by the current status of water-related issues:

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Inadequacy and poor quality of water supply for domestic purposes is increasingly becoming a concern in rural catchments of the Middle Mountains of Nepal. Water quantity is an issue in pocket areas of these catchments, while water quality is subject to concern in most of the water sources. Microbiological contamination in particular poses a risk to human health. In addition, sediment pollution during the monsoon season is perceived as an issue by the local residents. Elevated phosphate and nitrate levels in many water sources indicate intensive interaction with surface water hailing from agricultural areas and human settlements. These water quantity and quality concerns in two watersheds of Nepal, the Jhikhu Khola and the Yarsha Khola watersheds, are not isolated cases. Similar problems are reported from other watersheds monitored under the People and Resource Dynamics in Mountain Watersheds of the Hindu Kush-Himalayas (PARDYP) project in China, India, and Pakistan and the literature of this region.