An identification and mapping of flood susceptible areas in the Wardha Basin using frequency ratio and statistical index models, India

Abstract

Floods are one of the most catastrophic and widespread disasters that cause loss of lives, infrastructure, livelihoods, and people. Therefore, the identification and mapping of flood-prone areas is crucial for flood disaster management. The main objective of this study is to identify and map the potential flood areas of the Wardha Basin using frequency ratio (FR) and statistical index (SI) models. The analysis was based on twelve determinants such as elevation, slope, aspect, curvature, topographic wetness index (TWI), stream power index (SPI), rainfall, distance from the river, stream density, soil types, land use/land cover (LULC) and distance from the road. The flood inventory map was prepared based on 377 flood sites. Flood locations were randomly classified as 70% training samples (264 flood points) and 30% (113) testing samples. According to the FR model, approximately 1% of the area belongs to the very high flood vulnerability category and 39% to the very low flood vulnerability category. On the other hand, the SI model results showed that 4161 km2 (7%) of the basin area is very high susceptible to flooding, while very low flood sensitivity covers 6011 km2 (13%) of the basin area. A comparative analysis of the FR and SI models showed that the SI model is very accurate for the Wardha Basin because it has a higher area under the curve (AUC) for success rate (88.24%) than FR (86.99%). The results of this study will assist planners and decision-makers in flood management and risk reduction in the Wardha Basin.