HyEco: A hybrid hydrodynamic-cum-ecological modelling framework to demystify flood and human-health risks over flood-prone metropolis

This research introduces "HyEco" - an integrated framework comprising high-fidelity 3-way coupled hydrodynamic and ecological modelling. HyEco aims to capture the "unhidden tangible flood risks" and "hidden intangible public-health risks" in tandem, dynamically integrating flood and microbial processes at high spatio-temporal resolution. Urban flooding is being exacerbated by climate change and unregulated urbanization, posing significant risks to both the built environment and to public health. The latter is due to floodwaters often mobilizing a hazardous mix of untreated sewage, industrial effluents, and undesirable pollutants, leading to severe microbial contamination in the floodwaters. The research focuses on Delhi, India, a densely populated metropolis prone to recurrent urban flooding and associated health crises. The HyEco framework is used to simulate the 2023 mega-flood event.

The study's results show that approximately 63.5% of the Delhi region is categorized under 'high' to 'very high' flood risk zones. Through ecological modelling, the researchers determined that the level of microbial contamination - such as concentrations of Escherichia coli, or E. coli - far exceeded established safety thresholds. Lastly, a Quantitative Microbial Risk Assessment (QMRA) revealed elevated infection probabilities, particularly among children under repeated exposure and pedestrian splash exposures. From the research results, the HyEco framework is shown to offer a scalable and actionable tool for integrated flood risk management and climate-resilient public health planning.