Showing papers by "Emmanuel Ledoux published in 2011"
TL;DR: In this article, an upscaling method is proposed to benefit from high-resolution hydraulic modeling at local scale to improve the simulation of river stages at regional scale, where the rating curves are used as boundary conditions and allow to calculate river stage, which is then used to calculate the exchanges between aquifer units and river.
49 citations
TL;DR: In this paper, the authors proposed an improvement to the simple unsaturated zone (UZ) scheme NonsatSW used in STICS-MODCOU, based on a comparison with the mechanistic model Metis considered as a reference as it solves Richards' equation.
Abstract: For predicting the evolution of solute concentrations in groundwater and testing the impact of remediation policies, a coupling between the agronomical model STICS and the hydrogeological model MODCOU was implemented When applied to the Seine River basin, this model accurately represents the temporal evolution of average nitrate concentrations in the aquifer, but with large local errors
We propose an improvement to the simple unsaturated zone (UZ) scheme NonsatSW used in STICS–MODCOU The modifications are based on a comparison with the mechanistic model Metis considered as a reference as it solves Richards' equation A more realistic saturation profile and a varying percolation rate are integrated in NonsatSW This new model, named NonsatVG, is assessed by comparing it with NonsatSW and Metis In an ideal case, NonsatVG generates a solute transfer and a dispersion closer to that of Metis than of NonsatSW In real cases, without additional calibration, NonsatVG and Metis simulate better the average transfer velocities of the observed nitrate profiles
Furthermore, modifications in NonsatVG give a direct relationship between the depth of the water table and the saturation profile We obtain, therefore, as in Metis, an evolution of the solute transfer velocity depending on the piezometric level These dynamics are not simulated in NonsatSW
Despite a modified water transfer through the UZ, NonsatVG is also as valid as NonsatSW in the modelling of water transfer to the saturated zone
Finally, an application to the Seine basin shows that solute transfer velocities are lower with NonsatVG than with NonsatSW, but are in better agreement with literature Copyright © 2010 John Wiley & Sons, Ltd
12 citations
01 Jan 2011
TL;DR: Les travaux souterrains (tunnels, mines, stockages, exploitations de gisements geothermiques ou dhydrocarbures) provoquent des discontinuites dans le sous-sol qui jouent le role de drain pour l'eau as mentioned in this paper.
Abstract: Les travaux souterrains (tunnels, mines, stockages souterrains, exploitations de gisements geothermiques ou d'hydrocarbures) provoquent des discontinuites dans le sous-sol qui jouent le role de drain pour l'eau. Ces drains modifient les ecoulements et entrainent un rabattement du niveau piezometrique des aquiferes environnants. Ils modifient egalement les cours d'eau en surface en creant des pertes ou des resurgences. Enfin, les travaux souterrains introduisent generalement de l'air dans le sous-sol, ce qui provoque des reactions d'oxydation de la roche et modifie en consequence la qualite de l'eau.
01 Jan 2011
TL;DR: In this paper, the authors describe the methodology of investigation and the geochemical modeling approach that was developed on the Bellezane mining site where tailings are disposed of, and then proved to be adaptable to other tailings deposit sites.
Abstract: Uranium has been mined in the Limousin area (France) until the end of the 90s. Nowadays mines are closed and restored. Rehabilitation operations were devoted to assure the stability of land and infrastructures as well as to collect mine water and keep under control the radionuclide release into watersheds. Environmental monitoring is conducted by the operator (Areva-NC) under the control of the French administration. The present paper describes the methodology of investigation and the geochemical modeling approach that was developed on the Bellezane mining site where tailings are disposed of. This methodology and the corresponding modeling approach then proved to be adaptable to other tailings deposit sites.