Rapid geomorphological reconnaissance survey for road alignment in West Nepal

Abstract

A rapid geomorphological reconnaissance survey of the 112 km Baitadi-Darchula road currently under construction in the Middle Himalaya of West Nepal is described. The first 39 km of the proposed road was under construction when this 5 day survey commenced, to cover both the initial segment as well as an examination of the stability and practicability of the remainder of the alignment. A combination of landslide and erosion mapping along the proposed alignment and interpretation of air photographs led to the recommendation to abandon the remainder of the alignment and adopt an alternative route, considered to be more stable. The findings were later endorsed by a detailed feasibility study and preliminary design thus supporting the cost-effective use of rapid geomorphological surveys for engineering projects in unstable mountain terrain.