Enhancing Human Safety through Debris Flow Susceptibility Mapping and Risk Assessment in Wayanad District, Kerala

Debris flow is one of the Pervasive geological hazards in the Western Ghats claiming many lives and damaging properties every year. An extensive map illustrating debris flow susceptibility is essential in these regions, making flow routing models and vulnerability assessments necessary for effective risk management. In the present study the debris flow susceptibility was prepared by using r.randomwalk software utilizing Digital Elevation Model (DEM) and historical debris flow landslide incidence data from google imageries. The vulnerability assessment was carried out for buildings, roads, and agricultural areas as elements at risk. For present study 50 debris flow source areas were used to prepare the susceptibility map. About 771.87 sq.km (36.25%) area of the district is susceptible to debris flow impact, out of which approximately 210.83 km² (9.9%) area of the district falls within high-susceptibility zones. The village panchayat level risk map shows that Villages Meppadi and Pozhuthana of Vythiri taluk and Thirunelly of Mananthavady taluk are at the most risk to the debris flow events, while villages panchayats Vythiri and Mananthavady Municipality are the moderate risk. The research finding shows that the debris flow events are more probable on steep slopes and gullies at higher elevation, however, the extent is up to the lower land. The high debris flow susceptibility areas are dominant in zones characterized by slope range of 5°–15°, a negative plane curvature and flow accumulation of 0–2 associated with Open Forest. The map of vulnerable areas may assist planners in overall landslide risk management.