Olivier Bourgeois Département Sciences de la Terre et de l'Univers (Le réseau des diplômés de la formation Biologie/Géologie de l'Université de Nantes)
Geomorphology-based analysis and modelling of hydrochemical dynamics in rural watershed
Relief is underlying the dynamics of hydrological processes, and their space-time intergration of the watershed level. The drainage network is structuring within the relief: at the local scale through the drainage of flows from hillslopes and wetlands; and at the macroscopic scale by transferring flows towards the outlet where a composite signal finally emerges. Analysis, modelling and devonvolution of this structuring effect allow to understand and simulate the water dynamics across watersheds; to assess the effects of spatial arrangements of the natural and anthropogenic features within the watershed landscape, as well as land practices such as the agricultural ones; and to explore hydro-geographic good practices and alternatives.
Water related chemical fluxes (nitrogen, carbon…) are also structured by the drainage network, its interfaces with hillslopes and related compartments, and its overall geometry. This structuring effect is however much variable, depending on both chemical elements and hydrological variability, since diverse functionings enhance storage, leaching, transformations, dilutions…
Hydrogeomorphological and hydrochemical knowledge and methods have been extensively developed within the research unit UMR SAS, from several monitored rural watersheds of the agriculturally intensive Brittany region. These now allow to develop original coupling approaches. Hydrochemical knowledge will provide tracer informations to improve the geomorphology-based hydrological conceptualisation approaches. Conversely, the hydrogeomorphological modelling will allow to transfer and generalize local-scale hydrochemical knowledge towards mesoscale basins where societal challenges are huge (water pollution, green tides …). Finally the robustness of the geomorphology-based approach, enlarged to hydrochemical issues, will open avenues to explore scenarios of hydro-geographic land management.
References
de Lavenne, 2013 - Modélisation hydrologique à base géomorphologique de bassins versants non jaugés par régionalisation et transposition d'hydrogramme. PHD thesis, Agrocampus Ouest, Rennes. http://www6.rennes.inra.fr/umrsas/Publications/Theses
Publications of the agro-hydrology team: http://www.researcherid.com/rid/D-3726-2012
Conditions
3 years contract under the French regulations. National standard salary for a PHD. Starting October 2015.
Master diploma mandatory in geoscience, agronomy, physical geography, environmental modelling…
Offre n° 35981