Journal: Landslides

Authors: Kabin Lamichhane, Kamal Biswakarma, Biplav Acharya, Saroj Karki, Rajan KC, Mandip Subedi & Keshab Sharma

Publication Date: 18 July 2025

Abstract:

Nepal receives about 80% of its annual monsoon rainfall between June and September, with the heaviest rainfall occurring in the middle 2 months. Although rainfall-induced landslides and localized damage are common, the record-breaking 3-day rainfall from September 26 to 28, 2024, which caused economic losses exceeding 1% of the entire GDP of Nepal and 250 fatalities, is unprecedented. Most of the damage was concentrated in the Kathmandu Valley and surrounding areas, including Kavrepalanchok and Dhading. Twenty-five rainfall stations in central Nepal recorded their highest-ever 24-h rainfall during this event. This study provides observations of landslides and debris flows, identifies causative factors, and outlines short- and long-term strategies to enhance resilience in the Kathmandu Valley, which could also be applied to the surroundings and elsewhere with similar geology. Key causative factors include intense rainfall, pre-saturated slopes, weathered rock masses, poor road construction, unregulated sand mining, and reduced rainfall thresholds due to earthquake preconditioning. This study recommends integrated short- and long-term mitigation measures to address landslide and debris flow risks in the Kathmandu Valley. These include community awareness, real-time weather warnings, hazard mapping, structural and bioengineering interventions, and improved drainage. Policy actions involve revising legal frameworks, regulating mining, strengthening watershed management, and enforcing land use planning. Emphasis is placed on combining nature-based and engineered solutions tailored to Nepal’s diverse physiography and rainfall patterns, supported by institutional coordination and capacity building at the local level.

Read Full Paper