Geomorphological analysis of landslide and early warning system for landslide risk mitigation in Nepalese mid-hills.

Abstract The Nepalese Himalayas is one of the world’s most active mountain belts, with widespread natural hazards of various types, including landslides, which claim numerous lives and properties in Nepal. Landslides occur due to the combined effects of seismic activity, monsoon rainfall, and improper land-use practices. The prevention and mitigation of landslides are challenging for countries like Nepal, however, low-cost techniques such as bioengineering with low-cost early warning systems have been implemented in recent decades. The Methum landslide near Lalitpur was selected as a case study to investigate the landscape dynamics along with triggering factors, and to evaluate the effectiveness of a landslide early warning system (LEWS). The study assessed aerial photos, satellite images, and precipitation records and conducted multiple field visits to analyze patterns of landslide evolution, landslide risk, and potential triggers. Heavy rainfall, sloped terrace farming, and earthquakes are identified as major landslide triggers. LEWS, installed, measures rainfall, soil moisture, and displacement activity and generates an alarm if any of these parameters exceed the threshold set. This monitoring system is a cost-effective technique and exemplifies the reduction of landslide risk at the community level in the landslide-prone mid-hills of Nepal.