Applications of GIS and Remote Sensing for Landslide Vulnerability Assessment in Madikeri Taluk, Kodagu District, Karnataka

Abstract

This study aims to identify and mark the landslide prone zones in Kodagu district using GIS and Remote Sensing. Kodagu received the highest rainfall ever in the year 2018 breaking the 87-year-old record set in 1931. One of the worst-affected areas was Madikeri taluk due to the heavy intensity of rainfall on the high slopes leading to slope failure and consequent landslides. In this study, Maps of Landslide Prone Zones are prepared; quantitative information on slope/ground stability conditions in the study area currently unaffected (or thought to be unaffected) by landslides, but where the terrain geomorphology and geology may indicate potential future landslides is provided and this study also attempts to enumerate the consequences of landslides in Kodagu based on the analysis of statistical data.

Weighted Overlay Analysis method in ArcGIS used in this study aids to identify and localize the landslides susceptible areas. High intensity rainfall, high slopes (greater than 35°), weak soils, geology, geomorphology, drainage density, land use & land cover of the study area – were found to be the prime etiological factors for landslides. The Thematic Maps of these parameters are generated using the ArcGIS software to depict landslide susceptibility zones in different Zones Classified as - very low, low, moderate, high and very high vulnerability zones.

The study concludes that Monitoring Rainfall from the beginning to understand the pattens; Undertaking Scientific Slope modifications to ensure stability of the soil; Monitoring ground water levels and its changes to reduce the hazards of landslides; Developing Soil Retention walls in the low stability soil formation zones and Soil Pinning technique are need of the hour. The natural drainage systems should remain undisturbed and creation of new ponds, wells etc. should be avoided. The human activities of industrialization, quarrying, irregular human encroachment of forests, etc. need to be regulated carefully to maintain the balance.