We gathered hydraulic data characterizing over 1000 river segments. We developed international models to translate flow into hydraulics at any location. These hydraulic geometry models serve large-scale management of flows and habitats.

Temporal and spatial variations of river hydraulic characteristics (i.e. wetted width, water depth, flow velocity) across stream networks influence physical habitats and biodiversity, water temperature, nutrient and pollutants fluxes, sediment transport and associated ecosystem services. Therefore, improved hydraulic descriptions of catchments are essential for many ecological applications including the definition of ecological flows, the sound management of pollutions and the restoration of habitats. "At-a-station hydraulic geometry" relationships describe temporal changes in water depth, wetted width and velocity with the discharge at a given river reach. "Downstream hydraulic geometry" relationships describe spatial changes in hydraulics along a river or between reaches, at a given reference flow discharge (e.g., the median flow or mean annual flood flow). Although variations of both relationships have been widely documented, they are still largely unexplained. This work aims to improve knowledge about hydraulic geometry relationships and to develop models that predict hydraulic characteristics across river networks using an important intercontinental dataset of hydraulic measurements at reach scale. To predict hydraulic geometry parameters, many field-based, map-based or remotely sensed variables were analyzed in this study. This work show that hydraulic geometry is well explained by an intercontinental model, suggesting high generality of our models. The resulting hydraulic geometry models present considerable potential for improving national and/or catchment scale management tools. As an example of ecohydraulic application, we use our models to estimate the impacts of climate change on hydraulic habitats for fish in a large catchment

Références

• Gob, F., C. Bilodeau, N. Thommeret, J. Belliard, M.-B. Albert, V. Tamisier, J.-M. Baudoin, K. Kreutzenberger (2014) A tool for the characterisation of the hydromorphology of rivers in line with the application of the European Water Framework Directive in France (CARHYCE). Geomorphologie-Relief Processus Environnement, 57-72.
• Lamouroux, N. (2002) Estimhab: estimating instream habitat quality changes associated with hydraulic river management. Shareware & User's guide. Cemagref Lyon - Onema.
• Publications et communications :
• Morel, M., Tamisier, V., Pella, H., Booker, D.J., Navratil, O., Piégay, H., Gob, F., Lamouroux, N., 2019. Revisiting the drivers of at-a-station hydraulic geometry in stream reaches. Geomorphology 328, 44–56. https://doi.org/10.1016/j.geomorph.2018.12.007
• Morel M., Booker D., Stewardson M., Vivier A., Piégay H., Gob F., Tamisier V., Lamouroux N. (2018), Modélisation statistique de la géométrie hydraulique des tronçons à travers le réseau hydrographique et applications à la gestion des bassins versants / Modelling the hydraulics of river networks and management applications, I.S.RIVERS (2018), Lyon, France, June 2018.
• Morel M., Lamouroux N., Gob F. (2017), Revisiting the drivers of hydraulic geometry at reach scale in the hydrographic network, 9th International Conference of Geomorphology (ICG), New Delhi, India, November 2017.

Cite the thesis

Maxime Morel. Modélisation statistique de la géométrie hydraulique des tronçons de cours d'eau et applications dans la gestion écologique des bassins versants. Hydrologie. Université de Lyon, 2020. Français. ⟨NNT : 2020LYSE1083⟩. ⟨tel-03306715⟩

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