WORLD RESOURCES REPORT http://www.worldresourcesreport.org/ Nepal: Responding Proactively to Glacial Hazards World Resources Report Case Study SUSAN TAMBI MATAMBO, INDEPENDENT CONSULTANT ARUN BHAKTA SHRESTHA, INTERNATIONAL CENTRE FOR INTEGRATED MOUNTAIN DEVELOPMENT, NEPAL Suggested Citation: Matambo, Susan and Arun Shrestha. “World Resources Report Case Study. Nepal: Responding Proactively to Glacial Hazards.” World Resources Report, Washington DC. Available online at http://www.worldresourcesreport.org INTRODUCTION Glaciers hold about 70% of the earth’s freshwater (UNEP, 2002). They cover about 17% of the total area of the mountainous Hindu Kush-Himalayan (HKH) region of south and eastern Asia (Xu et al., 2007). Ten of the greatest rivers of Asia have their headwaters in the Hindu Kush-Himalayan Mountains. Thus, these mountains are often called “the water towers of Asia” (ICIMOD, 2009). Nepal is a small land-locked country in South Asia, occupying an area of 147,181 km 2 and with a population of about 29 million people (The World Bank Group, 2009). A major portion of the country's territory is occupied by mountainous terrain, which contains large numbers of glaciers and glacial lakes, as well as being home to 8 of the 10 highest mountain peaks in the world, including Mount Everest (8848 m). Glaciers cover about 9.6% of Nepal’s total land area (Sharma, 2010; ICIMOD, 2001). These glaciers are huge reservoirs of freshwater in frozen form which maintain the perennial flow of the major rivers of Nepal as well as the Ganges in India. As a result, changes in the hydrology of Nepalese rivers due to deglaciation could have regional consequences for water resource availability (Germanwatch, 2004). Glaciers are particularly susceptible to changing temperatures. It has been estimated that temperature rises of 0.04-0.09◦ C/year are occurring in Nepal, with greater warming at higher altitudes (Shrestha et al., 1999; Xu et al., 2007). Warmer temperatures cause accelerated melting of glacial ice, resulting in shrinkage of glaciers. This can lead to the formation of glacial lakes, some of which may burst out and cause flash floods known as glacial lake outburst floods (GLOFs) downstream in the valleys. The potential for loss of life and damage to infrastructure due to glacial lake outburst floods is varied depending on factors such as the size and depth of the lake, the nature of the outburst, the geomorphology of the river valley and elements exposed to the flash flood (Dixit & Gyawali, 1997; Shrestha et al., 2010). It is believed that glacial lake outburst floods may be one of the most important water-induced hazards in Nepal, with the potential to cause large socio-economic impacts in the country (United Nations, 2009; Network-Nepal, 2009). The Tsho Rolpa glacial lake, situated at the headwaters of the Rolwaling River Valley, is the largest moraine-dammed glacial lake in the Nepal Himalaya. A moraine-dammed glacial lake is