Assessment of Hydro-Meteorological Condition of Kathmandu (Nagdhunga)-Naubise-Mugling Road and Bridges

Abstract

The Kathmandu (Naghdhunga)-Naubise-Mugling (KNM) road has passed hilly area from Nagdhunga to Naubise (about 13%) after passing Naubise the road alignment passes river valley of the Mahesh Khola and Trishuli River, initially the road alignment follows on left bank of the Mahesh Khola valley upto Galchhi before meeting with Trishuli River. After Galchhi, road alignment follows the left bank of the Trishuli River valley upto Mugling (about 87%). The present study deals with the hydrological condition of the KNM road by analysing the existing hydro-meteorological data, reviewing the reports/documents of the previous studies and visiting the study area. The annual rainfall of the study area is found to be of increasing pattern. It is necessary to construct new crossing structures along with replacing some of the existing culverts in the existing road. Existing side drains are more or less adequate but the capacity might to be increased during  he improvement works. In the proposed new alignment 113 cross drains are necessary to construct and proposed side drains will be adequate for passing the design flood. Some of the stretches of the existing road are very close to the river and are vulnerable of being toe cutting and flooding from the river.