Development of Rockfall Early Warning System (REWS) for Prediction of Rockfall Hazard in Manikaran, NW Himalaya, India

ABSTRACT This study addresses the first rockfall early warning system (REWS) and the urgent need for monitoring and predicting rockfall hazards in the Parvati Valley, following a major landslide near the historic Manikaran Gurudwara in August 2015. The incident resulted in significant casualties and injuries, emphasizing the criticality of implementing preventive measures. The Gargi village, located approximately 1.5 km uphill from the Parvati River base, experiences recurring rockfalls, particularly during the monsoon season. Compounding the issue, the Manikaran-Bhuntar link road, a vital route to the Parbati Hydro Electric Project Stage-II by NHPC Limited, is situated within the runout zone of rockfall events. This research involves a comprehensive approach, including geological investigation, geomorphological zonation mapping, and a drone survey of the rockfall site upslope of Manikaran. Structural data from the rockfall site of the August, 2015 event was collected, and the active source area was identified on the southwest (SW) facing scarp. Anticipating future rockfall events, we have implemented an on-site wireless sensor network comprising tilt meters, crack meters, wireless nodes, piezometer, rain gauge, accelerometer, and gateway. The gateway wirelessly transmits real-time data to the Geotechnical Lab at the Department of Geology, Panjab University, Chandigarh, enabling early prediction of potential rockfall incidents. This integrated approach aims to predict the landscape evolution of the SW-facing scarp over the next 50 to 100 years, providing valuable insights into the potential rockfall hazard in Manikaran and the surrounding areas of Parvati Valley. The findings will contribute to proactive measures for safeguarding lives and infrastructure in the region.