Drone-based LiDAR survey to study land subsidence in Shimla

In order to conduct a comprehensive study of landslides and land subsidence incidents in the state’s capital, Himachal Pradesh State Disaster Management Authority (HPSDMA) would be conducting a drone-based Light Detection and Ranging (LiDAR) survey from October 21 to November 21.

The decision to conduct the drone-based survey was taken following recommendations from the Geological Survey of India (GSI) during a meeting held on September 7 with representatives from the district administration, GSI, Chandigarh, and other stakeholders.

The survey would be conducted by a firm — Convulsion Engineering Consultancy LLP — which has been tasked with compiling a detailed report. Anupam Kashyap, Deputy Commissioner, Shimla, said, “There has been a noticeable increase in landslides and land subsidence incidents in the city. In response to this, the state government sought advice from the GSI to conduct an in-depth investigation and develop strategies to mitigate occurrences of such incidents in the future,” he said.

“All necessary permissions have been obtained for conducting a drone survey in no-fly zones. A communication has been established with the military authorities for conducting the survey in areas under their jurisdiction,” the DC said. LiDAR technology utilises laser sensors mounted on drones to survey geographic features. LiDAR sensors send millions of laser pulses towards ground. After hitting the surface, these pulses bounce back to sensor mounted on drones, which measures the time taken for their return. This data helps create a precise 3D representation of the ground by collecting contact points that enable detailed mapping.