ABSTRACT
Road construction in Nepal started only from 1950 and about 16,800 km of road has been developed in the period of about 50 years. When road construction started around 1950, there was little knowledge about the fragile and hazardous geology of Nepal Himalayas. Significant work by geologists from various countries concerning the geology of Nepal came into fruition only after 1970 (Upreti 1999). The very first instance of the application of the knowledge of engineering geology was perhaps in the planning and construction of Lamosangu-Jiri road in 1980s. This road constructed under grant aid of government of Switzerland is considered as an environment friendly road in Nepal at present. This was achieved by extensive involvement of engineering geologists in the planning and construction phases of the road. Furthermore, when a section of the road in Charnawati watershed area failed in 1987 flood, the rehabilitation also involved extensive involvement of engineering geologists. Based on this experience, the knowledge of engineering geology and geotechnical engineering is normally accepted as required in planning and construction of roads at present. Dhital (2003) mentions following roads for which detailed landslide hazard mapping was carried out: (1) Tulsipur-Salyan road, (2) Ghorahi-Libang road, (3) Baitadi-Darchula road, and (4) Sagarmatha highway (Gaighat-DiktelOkhaldhunga). However, roads constructed before 1980, which include, major highways and feeder roads, were constructed without detailed landslide hazard mapping.
