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Titre : | Etude et caractérisation de la ressource en eaux souterraines au droit du domaine de Sandricourt |
Auteurs : | Alexandre LE BOULCH ; Hugo RAIN ; Ulric NAGNONHOUN ; Hugo RAIN ; Ulric NAGNONHOUN |
Type de document : | Mémoire d'initiation à la recherche |
Année de publication : | 2019 |
Concepts : | HYDROGEOLOGIE |
Résumé : | The study of the Sandricourt domain's subsoil has been required because of nitrate pollution in the groundwaters of the Cretaceous chalk. A pumping was already installed in the chalk to use the water in the domain. To deal with this problem, one of the solutions is the installation of a capture in the Lutetian-Cuisian aquifer, which appear in the cuesta overhanging the domain. Then the objective has been to identify and quantify the water resource of these formations, with the perspective of an exploitation. Few geophysical methods have been used to study the geological formations on the Lutetian cuesta, and to see the connections between these layers. This study has required to use two geophysical methods, the first one is the Electrical Resistivity, to display the subsoil structures with resistivity measures, and the Proton Magnetic Resonance Sounding (MRS) method, that use the excitation of the molecules of waters in the subsoil to see permeable formations saturated with water. With these two methods, researches have been made on regional geology and hydrogeology, with sampling and local measures. Tomographic profiles enable modelization of the geologic layers in 3D. The MRS enable to estimate the water resource in the Lutetian cuesta's layers, showing good values of permeability and water content at 30 to 40m depth, assigned to Cuisian sands. The use of these two methods also allowed to confront their effectiveness, showing the lack of precision of the tomographic method when the depth exceeds 50m. The data enable to have a view of the structures and characteristics of the aquifer but shows the limits of the geophysical methods when it comes to the determinations of the yield of the aquifer, that need the use of « destructive » methods like a drilling. |
Spécialité : | Géologie |
Numéro de promo : | 81 |
numéro MIR : | 849 |