H2O - Hydrology, Eco-Hydraulics and Waves

Key words: Hydrology, ecological continuity, floods, watersheds

The Eco-hydraulics and hydrology theme concerns natural flows over complex bottoms at different scales, directly related to operational issues ranging from flood forecasting to the restoration of ecological continuity (framework directive on water 2000/60/CE).

This group is structured by daily interactions with the staff of the OFB (French Biodiversity Office – Office Français de la Biodiversité) hosted at the IMFT. A cooperation agreement between the supervisory authorities of the IMFT (Toulouse INP, CNRS and UPS), the OFB and Institut Pprime de Poitiers formalizes a shared research project and the pooling of human and financial resources, thus defining the activities and functioning of the OFB / IMFT / Pprime “Ecohydraulic” R&D pole.

Methodology

The approaches developed are based both on experimental studies in the laboratory or on site and on numerical modeling tools. The originality of this work consists in taking into account the multi-scale variability, from highly three-dimensional local processes to the reach of rivers or the watershed.

The numerical models developed are transferred in the medium term to an operational use (MARINE: hydrological model for flood forecasting, Cassiopée: calculation aid software for the design of fishways – http://cassiopee.g-eau.net).

Scientific Themes

At the European and national level, in the field of turbulent free-surface flows on complex bottoms, the experimental and metrological expertise of the H2O group has been clearly identified and recognized in the European project Hydralab+  (2015-2019, https://hydralab.eu/) and the ANR Flowres (2015-2018, https://flowres.irstea.fr/en/).

In particular, the development of innovative optical techniques around PIV (stereoscopic multi-planar and/or scanned) or umbroscopy (integrated PTV at channel scale) now allows a rigorous change of scale from local 3D measurements to a vertical 1D description (Saint-Venant equations), giving access to all relevant components of the local flow. This expertise also includes the joint use of acoustic techniques, which are mostly used in other European laboratories or in situ studies.

Multi-plane PIV measurements in a canopy of regular prisms. (a) Reynolds tensor in the central vertical plane through the center of the prisms. (b) and (c) Reynolds tensor in a horizontal plane above the canopy and in the canopy (horizontal lines in figure a) reconstructed from 9 vertical planes of PIV measurements.

The “Hydrology at the catchment scale” theme includes several actions ranging from numerical rainfall-flow modeling to the estimation of the uncertainty associated with the response of a hydrodynamic model. The research work carried out is mainly dedicated to the improvement of the understanding and representation of flash flood dynamics, with in particular the identification of the dominant processes according to the characteristics of the rainfall event and the catchment area considered. Distributed modeling is the tool used to provide these elements of understanding. As a result, special attention is also devoted to the estimation of parameters in hydrodynamic models in general, as well as to the evaluation and propagation of uncertainties associated with this type of modeling. For this purpose, it was necessary to appropriate and adapt various mathematical techniques, in particular sensitivity analysis or data assimilation, in order to analyze the behavior and better constraint hydrodynamic modeling.

The research in hydrological modeling dedicated to flash floods has resulted in a high level of scientific production, while ensuring a transfer to the operational actors in the field. The SCHAPI-IMFT research agreement, renewed since 2006, is a striking example: one of the main missions of the SCHAPI (Service Central d’Hydro-météorologie et d’Appui à la Prévision des Inondations) is to support flood forecasting services at the national level. The MARINE model is part of the hydrological modeling platform PLATHYNES (PLATeforme HYdrologique pour la modélisatioN des Écoulements Spatialisés) of the SCHAPI, which is currently being tested and used for operational forecasting by several flood forecasting services. It is also registered with the Agency for the Protection of Programs. The H2O group is also very active in the international research program HyMeX – HYdrological cycle in the Mediterranean EXperiment

(http://www.hymex.org/).

The MARINE model: Modeling and Anticipation of Runoff and Flooding for Extreme Events. Schematic of the represented processes and implementation in PLATHYNES, the modeling platform with operational vocation of the SCHAPI

Within the framework of the IMFT/OFB/PPRIME Pôle Écohydraulique, a first phase of studies has allowed to understand the flows within the fish passes, such as the macro-roughness ramps for upstream migration and the ichtyocompatible water intakes for downstream migration, and in fine to improve their design criteria. This first phase has also resulted in the design and manufacture of a tiltable flume made entirely of glass intended to evaluate the efficiency of fish passes in relation to hydrodynamic characteristics (OFB Macrorugosité 2 project). This flume allows the development of innovative optical metrology, in particular for flows with steep slopes. A second phase of studies, currently underway, consists of acquiring feedback in situ, on devices that comply with the latest recommendations, to evaluate the effectiveness of fish passes. These studies, which are already well advanced concerning downstream migration, confirm the achievement of high efficiencies (80-100% for salmon juveniles and 95-100% for silver eels), helping to reconcile hydropower, a renewable energy source, and the restoration of fish populations. These results validate the operational transfer of technical recommendations on the design of devices. Our expertise on this topic is widely recognized beyond the national level, particularly in the European programs in which the Pôle Écohydraulique is involved: H2020 FIThydro and Interreg SudoAng.

Tiltable hydraulic flume of the Environmental Fluid Mechanics Platform

Theses and internships offered by the group

Members of the group

NomStatutGroupePage personnelleBatimentN° de Bureau
Astruc DominiqueChercheur Toulouse INP - Maître de ConférencesH2OEscande116
Cassan LudovicChercheur Toulouse INP - Maître de ConférencesH2OEscande105
Cavalcanti FlaviaPost-DoctoranteH2OEscande107
Courret DominiqueIngénieur OFBH2OEscande117
Dartus DenisProfesseur des Universités Toulouse INPH2OEscande115
De Billy VéroniqueIngénieure OFBH2OEscande113
Hauw DominiqueGestionnaire OFBH2OEscande102
Hosseinzadeh AtiyehDoctoranteH2OEscande107
Labedan MathildeIngénieure d'étudesH2OEscande107
Laurens PascaleChercheur UT3 - Maître de ConférencesH2OEscande115
Mercier OlivierTechnicien OFBH2OEscande101
Moulin FrédéricChercheur - Maître de Conférences Toulouse INPH2OEscande116
Poulet NicolasIngénieur OFBH2OEscande113
Richard SylvainIngénieur OFBH2OEscande117
Roux HélèneMaître de Conférences, responsable du groupe H2OEscande105
Sagnes PierreMaître de Conférences détaché, Chef de pôle OFBH2OEscande104
Thual OlivierChercheur - Professeur des UniversitésH2OCastex
Tomanova SylvieIngénieure OFBH2OEscande101

Publications of the group

RSS 10 dernières publications déposées dans OATAO – H2O