Assessing landslide risk on heterogeneous agricultural landscape in rural Himalayas

Agriculture is the main livelihood and food security source in India's rural Himalayas. At the same time, frequent landslides are increasing the risk of agriculture, particularly under the changing scenario of climate. However, a few studies explored the impact of landslides on the agricultural land in the Himalayan region. Therefore, the study focuses on two-fold objectives: i.e. (i) to analyze the impact of landslides on losing agricultural land, and (ii) to assess the risk of agricultural land to landslides. We consider the Darjeeling Himalayas of India as a case study of this research. The study area is composed of diverse agricultural lands such as tea plantations, pomiculture, and cropland. To achieve these objectives, a detailed landslide inventory database is generated that covers landslides from 2001 to 2024. We develop a GIS-based framework of the risk assessment using five indicators namely the susceptibility index of landslides, temporal probability index of landslides, total affected area index of landslides, proximity index of landslides, and recovery index of agricultural land. The study considers each village as a unit of analysis. Further, a composite risk index was developed by aggregating the five indexes.  Further, the spatial pattern of risk is analyzed using hot spot and cold spot analysis. The study found varying impacts and risks of landslides on tea plantations and frame land. The study will help to develop sustainable agricultural policy in the rural Himalayas.

Key words: Landslides; Risk index; Agricultural land; GIS; Hot-spot analysis; Darjeeling