Predicting Flood Dynamics in the Narmada Basin: Integrating LULC Projections with Hydrodynamic Modelling

Flood risks in river basins are increasingly exacerbated by rapid Land Use and Land Cover (LULC) changes driven by urbanization, deforestation, and agricultural expansion. The Narmada basin, particularly its lower reaches, serves as a critical case study due to its hydrological importance, diverse landscapes, and susceptibility to monsoonal flooding. This study explores the interplay between evolving LULC patterns and flood dynamics in the lower Narmada basin through advanced machine learning and hydrological modelling techniques. The analysis starts by classifying historical and current LULC patterns using remote sensing data from Landsat and Sentinel-2, leveraging Support Vector Machine algorithms for accurate mapping. Future LULC scenarios are predicted using a Cellular Automata-Markov Chain model under various development trajectories. Rainfall data, combined with projected LULC maps, is processed through HEC-HMS to simulate rainfall-runoff relationships and estimate discharge. These discharge values are then used as inputs in HEC-RAS for detailed flood simulations, providing insights into flood extents and inundation depths under extreme rainfall events. Additionally, Long Short-Term Memory (LSTM) networks are employed to analyse and predict flood-prone areas by understanding the complex relationships between LULC changes, rainfall, and runoff. Preliminary findings reveal significant urban expansion and vegetation loss, intensifying flood risks in downstream regions, particularly near Bharuch city. Simulated inundation maps indicate substantial increases in flood extents in urbanized zones, emphasizing the need for adaptive land management strategies and optimized barrage operations. By combining AI-driven methodologies, hydrological modelling (HEC-HMS), and hydrodynamic simulations (HEC-RAS), this study offers a comprehensive framework for addressing flood risks in rapidly transforming landscapes. The results provide actionable recommendations for urban planning, flood mitigation policies, and sustainable water resource management in the Narmada basin.