Estimating the Volume of Direct Runoff from Built-up Areas in the Kathmandu Valley

Kathmandu Valley, Nepal is facing significant urbanization and land use change, which can have adverse impacts on water resources in the region. In this study, we analyzed the land use data and runoff volume data from 2000 to 2030 to assess the impact of urbanization and land use change on runoff in Kathmandu Valley. The land use data showed an increase in the built-up area from 80.13 sq. km in 2000 to 162.53 sq. km in 2030, while the forest area slightly decreased from 246.53 sq. km in 2000 to 246.39 sq. km in 2030. The runoff volume data showed an increase in the amount of runoff from 89.55 million cubic meters in 2000 to 163.53 million cubic meters in 2030, with a peak in 2030. This increase in runoff volume is attributed to the increase in the built-up area and decrease in forest area. The results of this study highlight the need for sustainable land use planning and management in Kathmandu Valley to minimize the adverse impacts of urbanization on water resources.