How do river basin characteristics influence flood wave propagation?

This project aims to better understand how upland river basin morphometry and geomorphology influences flood characteristics. Billions of people live close to rivers and experience the negative effects of flooding.Their risk exposure is increasing due to climate change altering the magnitude and frequency of fluvial flooding globally.River catchment geomorphology filters a landscape's response to rainfall by shifting hydrological and sedimentological connectivity in the basin.Previous work has shown in-channel morphological changes can affect flood risk; this work will look beyond the channel and at the hillslope-river interface.Quantification of how catchment evolution and structure impacts flooding will allow disentanglement of basin geomorphology from other factors such as land cover, human disturbance and climate change on flood dynamics.This work will link upland river basin processes to downstream floodplains to forecast how antecedent landscape conditions will alter subsequent flood events.The project's goal will be achieved by a series of three papers.The first paper will look at an upland region, either in the UK,North America or the Himalayas,to observe how
past and present basin geomorphology impacts flood generation by comparing basins.Region choice depends on the level of geomorphic dynamics required and the clarity of river-hillslope coupling. Basin morphometrics and geomorphic change rates are quantified using satellite imagery (dependent on region chosen), digital elevation models(potentially from satellite photogrammetry)and old maps. Downstream gauging stations will help elucidate basin geomorphometry influence on various flood recurrence intervals generated from a Generalized Extreme Value distribution. Catchments with similar rainfall generation mechanisms (extracted from rainfall radar data), land cover and seasonality will be compared to remove those impacts on flood generation.In the second paper, identified basin morphological impacts on flood characteristics will be investigated using a model (e.g. Hydro-JULES). By using 'perfect landscapes' and natural ones seen in the first paper,Monte Carlo simulations will elucidate howgeomorphological change trajectories in catchments may influence flooding downstream.Landscape change influence will be quantified on how it could change future flood risk regarding flood peak duration,magnitude and lag time.The final paper will link themes explored in the first papers by applying found concepts to other regions.If it was possible at this stage,a global analysis of upland river basin geomorphology on flood risk could be undertaken.This could link with climate change influence on landscape evolution to allow better prediction of how landscape development could alter flood hazards.The three-paper framework allows for project adaptability if aspects become unachievable or external factors change. It also allows for a gradual increase in the work output and knowledge depth, providing chances to develop further skills and methods required. The project offers ample opportunities to collaborate with universities, business stakeholders and policymakers internationally. Knowledge garnered in this project is applicable to work ranging from Natural Flood Management to the creation of Hydro-JULES. It would provide a basis for separating basin geomorphometry from other factors influencing flood-change signals through time. Better prediction of how river catchment morphology influences flood seasons will allow for better preparedness of global flood risk.