10 research outputs found

    Discours prononcé sur la tombe de M. François Rude, par J.-B. Delestre

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    Évaluation par modĂ©lisation inverse des apports latĂ©raux en crues et des concentrations en solutĂ©s : application sur une plateforme expĂ©rimentale et sur des bassins naturels

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    International audienceThis article discusses the areas and limits of application of the inverse model of the diffusing wave equation proposed by Moussa [1996] to calculate the hydrograph of the lateral flow and the solute concentrations (considered conservative over the duration of monitoring), and discusses the interest of the experimental platform for the validation of the model and its transfer for applications on natural basins. This work first allowed the creation of an experimental platform characterized by low space occupation, short experimental duration, high measurement precision, high quality and reproducible experimental curves, low water consumption and energy, and the possibility of testing a wide variety of hydrograph scenarios. To illustrate the approach, the applications are carried out on a rectangular canal and on a physical model of the downstream part of the Var. The platform provides a large number of flood events in a controlled environment, essential for verifying and validating the hydraulic models: diffusing wave, inverse model and Depth-Discharge-Concentration hysteresis. This work also allowed the development and application of the inverse model to calculate hydrographs of lateral gains and losses as well as concentrations. The applications on the experimental canal made it possible to validate the model equations, and the applications on natural basins made it possible to evaluate the lateral exchange flows and to propose a hydrological functioning diagram in flood of the basinCet article discute les domaines et limites d’application du modĂšle inverse de l’onde diffusante proposĂ© par Moussa [1996] pour calculer l'hydrogramme de l'Ă©coulement latĂ©ral et les concentrations en solutĂ©s (considĂ©rĂ©s comme conservatifs sur la durĂ©e du suivi), et discute l’intĂ©rĂȘt de la plateforme expĂ©rimentale pour la validation du modĂšle et son transfert pour des applications sur des bassins naturels. Ce travail a permis en premier la rĂ©alisation d’une plateforme expĂ©rimentale caractĂ©risĂ©e par une faible occupation de l'espace, une courte durĂ©e expĂ©rimentale, une grande prĂ©cision de mesure, des courbes expĂ©rimentales de haute qualitĂ© et reproductibles, une faible consommation d'eau et d'Ă©nergie, et la possibilitĂ© de tester une grande variĂ©tĂ© de scĂ©narios d'hydrogrammes. Pour illustrer la dĂ©marche, les applications sont menĂ©es sur un canal rectangulaire et sur un modĂšle rĂ©duit de la partie aval du Var. La plateforme permet de disposer d’un grand nombre d’évĂ©nements de crue en milieu contrĂŽlĂ©, indispensables pour vĂ©rifier et valider les modĂšles hydrauliques : onde diffusante, modĂšle inverse et hystĂ©rĂ©sis Hauteur-DĂ©bit-Concentration. Ce travail a aussi permis le dĂ©veloppement et l’application du modĂšle inverse afin de calculer les hydrogrammes de gains et de pertes latĂ©raux ainsi que les concentrations. Les applications sur le canal expĂ©rimental ont permis de valider les Ă©quations du modĂšle, et les applications sur des bassins naturels ont permis d’évaluer les flux d’échanges latĂ©raux et de proposer un schĂ©ma de fonctionnement hydrologique en crue du bassi

    Modelling lateral flow and solute concentration in a river channel during flood events

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    International audienceLateral flow L is a major process during flood events, which can represent either a gain for the reach such as surface runoff from hillslopes or water table drainage, or a loss such as overbank flow during extreme floods or infiltration into the aquifer. Despite recent progress in measurements, lateral flow cannot be measured and experiments cannot be carried out in situ due to the difficulty of controlling all exchanges along a river (river – hillslope – aquifer – overbank flow).This work aims at evaluating L and the corresponding solute concentration in a channel using the inverse model of the Diffusive Wave Equation DWE. Three applications are shown. First we realize 62 experimental flood scenarios on a novel experimental channel in the laboratory where the inflow, the outflow and the lateral exchanges are highly controlled, and we validate the hypotheses of the DWE inverse model and its ability to reproduce complex shapes of lateral flow hydrograph and solute concentration dynamics. Second, we apply the methodology on two French karst rivers in order to establish a scheme for surface-subsurface exchange during flood events. Third, application was carried on a physical scale model of the Var river Southern France to model the stage-discharge and concentration-discharge hysteresis relationships during flood events. Results are encouraging to extend this approach to a variety of sites, notably those affected by significant surface-subsurface-overbank flow interaction. The coupled experimental-modelling approach, for water and conservative solutes, opens promising perspectives regarding the evaluation of lateral flow on real channel

    Évaluation par modĂ©lisation inverse des apports latĂ©raux en crues et des concentrations en solutĂ©s : application sur une plateforme expĂ©rimentale et sur des bassins naturels

    No full text
    International audienceThis article discusses the areas and limits of application of the inverse model of the diffusing wave equation proposed by Moussa [1996] to calculate the hydrograph of the lateral flow and the solute concentrations (considered conservative over the duration of monitoring), and discusses the interest of the experimental platform for the validation of the model and its transfer for applications on natural basins. This work first allowed the creation of an experimental platform characterized by low space occupation, short experimental duration, high measurement precision, high quality and reproducible experimental curves, low water consumption and energy, and the possibility of testing a wide variety of hydrograph scenarios. To illustrate the approach, the applications are carried out on a rectangular canal and on a physical model of the downstream part of the Var. The platform provides a large number of flood events in a controlled environment, essential for verifying and validating the hydraulic models: diffusing wave, inverse model and Depth-Discharge-Concentration hysteresis. This work also allowed the development and application of the inverse model to calculate hydrographs of lateral gains and losses as well as concentrations. The applications on the experimental canal made it possible to validate the model equations, and the applications on natural basins made it possible to evaluate the lateral exchange flows and to propose a hydrological functioning diagram in flood of the basinCet article discute les domaines et limites d’application du modĂšle inverse de l’onde diffusante proposĂ© par Moussa [1996] pour calculer l'hydrogramme de l'Ă©coulement latĂ©ral et les concentrations en solutĂ©s (considĂ©rĂ©s comme conservatifs sur la durĂ©e du suivi), et discute l’intĂ©rĂȘt de la plateforme expĂ©rimentale pour la validation du modĂšle et son transfert pour des applications sur des bassins naturels. Ce travail a permis en premier la rĂ©alisation d’une plateforme expĂ©rimentale caractĂ©risĂ©e par une faible occupation de l'espace, une courte durĂ©e expĂ©rimentale, une grande prĂ©cision de mesure, des courbes expĂ©rimentales de haute qualitĂ© et reproductibles, une faible consommation d'eau et d'Ă©nergie, et la possibilitĂ© de tester une grande variĂ©tĂ© de scĂ©narios d'hydrogrammes. Pour illustrer la dĂ©marche, les applications sont menĂ©es sur un canal rectangulaire et sur un modĂšle rĂ©duit de la partie aval du Var. La plateforme permet de disposer d’un grand nombre d’évĂ©nements de crue en milieu contrĂŽlĂ©, indispensables pour vĂ©rifier et valider les modĂšles hydrauliques : onde diffusante, modĂšle inverse et hystĂ©rĂ©sis Hauteur-DĂ©bit-Concentration. Ce travail a aussi permis le dĂ©veloppement et l’application du modĂšle inverse afin de calculer les hydrogrammes de gains et de pertes latĂ©raux ainsi que les concentrations. Les applications sur le canal expĂ©rimental ont permis de valider les Ă©quations du modĂšle, et les applications sur des bassins naturels ont permis d’évaluer les flux d’échanges latĂ©raux et de proposer un schĂ©ma de fonctionnement hydrologique en crue du bassi
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