S. R. Bajracharya
Central Department of Geology
Tribhuvan University, Kirtipur, Kathmandu, Nepal
V. K. Verma
Colombo Plan Expert
The oval shaped Kathmandu Valley stretches 30 km E-W and 25 km in N-S direction encompassing an area of about 647 sq. km. The valley is drained by 10 different tributaries of the Bagmati River forming a typical Centripetal drainage system. The drainages consisting of Dhobi Khola from Shivpuri Range, Bishnumati Khola from Shivapuri and Nagarjung ranges, Hanumante and Manohara Kholas from Nagarkot range, Nakhu, Kodky and Gosawari Kholas from Phulchowki range and Balkhu and Bosan Kholas from Chandragiri range, have originated from different directions.
Bagmati, Dhobi, Balkhu and Bosan Kholas form the 4th order network whereas the remaining drainages form the 5th order network and the Kathmandu Valley as a whole is taken into the 6th order network.