Large-Scale Hydro-Morphodynamics

Scope

This is my main research project and likely the leitmotif of my career. Simulating river hydrodynamics and morphodynamics — computing flow depth, velocity and shear stress fields, as well as sediment transport through space and time for a given discharge — is essential for analysing fluvial processes across scales, beyond simple mass-balance budgets. However, the need to solve the computationally demanding Shallow Water Equations restricts current models (e.g., Delft3D, HEC-RAS) to small spatial domains and short timescales. To fully exploit high-resolution DSMs and capture fluvial processes over geological times, new efficient methods are required to derive high-resolution hydrologic and morphologic metrics from large datasets using physics-based approaches.

These methods are critical to address major unresolved questions related to multi-scale behaviour: how much of the present-day topography reflects long-term tectonic and climatic evolution versus the imprint of extreme floods? Can the frequency and magnitude of extreme floods be inferred from topography alone? Are morpho-sedimentary records truly representative of tectonic and climatic conditions, or do they merely stochastically record isolated events?

This project leverages a major shift in data availability. Geomorphology at global scale has long relied on low-resolution DEMs (e.g. 30 m SRTM) where most rivers are sub-pixel. Today, satellites such as Pléiades Neo provide metre-scale DSMs with repeated temporal coverage. Even higher resolutions are achieved through airborne LiDAR, with national-scale programmes becoming increasingly common (e.g. LiDAR HD in France, and comparable initiatives in Switzerland, Austria, Italy, Germany, the USA and New Zealand).

We are not limited by data availability anymore, but by our ability to process and analyse it.