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Titre : | Études complémentaires de la ressource en eaux souterraines (études géologique et hydrogéologique) au droit de l'île d'Arz (Bretagne - Morbihan) et de l'équilibre eau douce/eau salée |
Auteurs : | Etienne CHAMBON ; Felix DE TALHOUET-ROY |
Type de document : | Mémoire d'initiation à la recherche |
Année de publication : | 2021 |
Concepts : |
POLLUTION
AQUIFERE RESSOURCES DEVELOPPEMENT DURABLE PENURIE PUITS GEOPHYSIQUE |
Résumé : | The Island of Arz is located in Brittany in the Gulf of Morbihan. Since 2018, two investigation campaigns have been carried out by students from previous classes within the framework of the Dissertation of Initiation to Research. This report is a continuation of the work carried out over the last three years. In September 2020, the total number of wells inventoried on the Island was 72, of which 57 were sampled. Such a quantity of wells on an Island of 330 hectares characterizes the need of the islanders to access natural water resources. The geological history of the Armorican massif shows that the aquifer studied is similar to a basement fissured aquifer. The insularity and the geological context of the area raise issues of sustainable development. Water scarcity and pollution have an impact on the social and economic environment of the Gulf Islands. The objective is to anticipate the needs of the Island and the evolution of water resources. The comparison and linking of data acquired on the Island over three consecutive years allows to observe the phenomena of salt intrusion over time, and to evaluate the evolution of its water resources. In order to respond to current problems, the study of the tidal phenomenon and the study of the island aquifer were carried out using water analysis methods, geophysical methods, and bibliographical research. The acquisition of piezometric measurements from each of the wells studied, the results of the chemical analyses of the samples, and the various electrical profiles, as well as their comparison with pre-existing data, will make it possible to propose elements of response to the problems raised. A second field campaign in April 2021 will also allow to deepen the study of the water resources of the Island of Arz. |
Spécialité : | Géologie |
Numéro de promo : | 83 |
numéro MIR : | 905 |