Prediction of flood risk zone of Ghaggar river basin, India using graph theory technique

Ghaggar river basin of northern India has been experiencing flash floods many times during the last three decades despite locating in semi-arid/arid regions. Identification of the flood risk zone of a basin is essential where the availability of flood-related data is limited. The present study proposed the graph theory to identify the flood risk zone using spatial database of the digital elevation model, land use and land cover, soil cover, population, rainfall, drainage density, distance from roads, rivers, and flood shelters. Further, the results obtained from graph theory were compared with the results obtained by Analytical Hierarchy Process. It is observed that graph theory can also identify the flood risk zone of a basin precisely with acceptable accuracy. Around 94.1% of the study area is observed to have a high flood risk using Analytical Hierarchy Process, whereas 100% area is observed to have a high flood risk using graph theory.