The Bagmati River is the principal river of the Bagmati Basin (ca. 3640km2) in central Nepal. The river, fed by springs and monsoon rainfall, originates in the north of Kathmandu Valley (the capital of Nepal) and drains across the Mahabharat Range to the Gangetic plain. The Basin transacts three distinct latitudinal physiographic zones (Mountain, Siwalik and Terai) of the Nepal Himalayas. Hard rock geological formations at the Basin headwaters stand out as a resistant ridge complex compared to the weak and fragile rock formations at the middle stretches of the Basin.
The Bagmati Basin currently faces a number of serious environmental and ecological challenges. Urbanization and industrialization of the Basin headwaters at Kathmandu contributed to water quality deterioration with regional consequences on the aquatic ecosystem and on the health of the downstream sub-basin’s user groups. Increasing population pressure on the fragile mountain slopes has also resulted in the rapid degradation of the natural resources. As a consequence, deforestation, soil erosion, landslides, siltation etc. are occurring in the upper and middle sections whereas sedimentation and flooding is frequent in the lower stretches of the watershed. This synergetic effect is of concern for the sustainable use of the resources and infrastructures.
This paper deals with the various facets of environmental management and monitoring of the watershed for its sustainable development.