• Fulltext

       

        Click here to view fulltext PDF


      Permanent link:
      https://www.ias.ac.in/article/fulltext/jess/126/08/0116

    • Keywords

       

      Debris flow; watershed; GIS; modelling; mapping; analytical network process (ANP).

    • Abstract

       

      Rapid debris flows, a mixture of unconsolidated sediments and water travelling at speeds >10 m/s are the most destructive water related mass movements that affect hill and mountain regions. The predisposing factors setting the stage for the event are the availability of materials, type of materials, stream power, slope gradient, aspect and curvature, lithology, land use and land cover, lineament density, and drainage. Rainfall is the most common triggering factor that causes debris flow in the Palar subwatershed and seismicity is not considered as it is a stable continental region and moderate seismic zone. Also, there are no records of major seismic activities in the past. In this study, one of the less explored heuristic methods known as the analytical network process (ANP) is used to map the spatial propensity of debris flow. This method is based on top-down decision model and is a multi-criteria, decision-making tool that translates subjective assessment of relative importance to weights or scores and is implemented in the Palar subwatershed which is part of the Western Ghats in southern India. The results suggest that the factors influencing debris flow susceptibility in this region are the availability of material on the slope, peak flow, gradient of the slope, land use and land cover, and proximity to streams. Among all, peak discharge is identified as the chief factor causing debris flow. The use of micro-scale watersheds demonstrated in this study to develop the susceptibility map can be very effective for local level planning and land management.

    • Author Affiliations

       

      Evangelin Ramani Sujatha1 Venkataramana Sridhar2

      1. Centre for Advanced Research on Environment, School of Civil Engineering, SASTRA University, Thanjavur 613 401, India.
      2. Biological Systems Engineering Department, Virginia Tech, Blacksburg, VA 24061, USA.
    • Dates

       
  • Journal of Earth System Science | News

© 2017-2019 Indian Academy of Sciences, Bengaluru.