The Manahara River is one of the largest tributaries of the Bagmati River in the Kathmandu Basin. Lateral shifting of channel, bank erosion, and destruction of fertile land and inundation of crop lands are some of the major problems. Five representative segments of the Manahara River were studied for evaluating channel stability condition and river environment, and several stations along the river channels were studied for streambank recession, and bank erosion and lateral instability hazard indexing and mapping.