Abstract

Chure hills are formed with the highly fragile, weak young sedimentary rocks and are environmentally sensitive. Road construction in this region is a big challenge to conserve the Chure from landslide. Occurrence of landslide hazard along the highway is the threat to the objective of timely, efficient and qualitative construction of highway. Landslide hazard map can greatly help in fixing and shifting of the alignment to reduce the loss of life and property.

This study “Landslide hazard assessment using UAV imagery and GIS for road planning and development in Chure area: Sindhuli-Hetauda section” aims at creating the hazard map, landslide inventory map and designation of hazard levels in one of the sensitive areas: Chure section. With the use of the Unmanned Aerial Vehicles (UAVs) as the primary means of carrying out the topographical surveying, the study used the Digital Surface Model (DSM) and the orthomosaic map produced from the UAV survey in acquiring the relevant results for fulfilling the study objectives. The survey area being ~100Km in length along the road alignment, four of the most crucial sites on the basis of existing landslide area and impact of those landslide in road, cultivation and settlement in the study area were selected for surveying. The study concluded that use of UAV for hazard mapping has good, accuracies and high resolution data. The Root Mean Square Error (RMSE) of the survey for the individual sites was found to be 0.001m, 0.045 m, 0.044 m and 0.804 m, respectively. A detailed topographical map of the area was created, along with the hazard map, including the factors such as slope, aspect, curvature, elevation, lithology, distance to road, distance to river and soil type. Furthermore, the hazard levels for the surveyed area were also obtained: the largest area being medium 60.68%, 57.45%, 71.21% and 71.16%, respectively, followed by high 32.59%, 18.91%, 17.03% and 11.54% respectively and low 6.73%, 23.64%, 11.76% and 17.30%, respectively in Chattiwan, Bhawanchuli, Gurji and Hakpara. It was also concluded that the forest area is at high risk followed by the bush and the settlement area in the Chattiwan, Bhawanchuli and Hakpara site and the cultivable land followed by the bush and the settlement area were found to be in high risks in the fourth site (Gurji).