1. Insights into saline intrusion and freshwater resources in coastal karstic aquifers using a lumped Rainfall―Discharge―Salinity model (the Port-Miou brackish spring, SE France)
- Author
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Jean-Baptiste Charlier, Bruno Arfib, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Service National d'Observation sur le KARST (SNO Karst), Institut national des sciences de l'Univers (INSU - CNRS), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), This paper is part of the KarstEAU project (http://www.karsteau.fr) funded by the ‘‘Agence de l’Eau Rhône-Méditerranée-Corse', ‘‘Conseil Général du Var', ‘‘Conseil Général des Bouches du-Rhône' and ‘‘Région Provence Alpes Côte d’Azur'., Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), and Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)
- Subjects
Hydrology ,geography ,Water resources ,Hydrogeology ,geography.geographical_feature_category ,Coastal aquifer ,Lumped model ,Brackish water ,0208 environmental biotechnology ,Karst ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,Aquifer ,02 engineering and technology ,6. Clean water ,020801 environmental engineering ,Salinity ,Mediterranean sea ,Spring (hydrology) ,Saline intrusion ,Mediterranean Sea ,Seawater ,[SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology ,Geology ,Water Science and Technology - Abstract
International audience; The aim of this study was to develop a conceptual model of saline intrusion within coastal karst aquifers by analyzing Rainfall–Discharge–Salinity data and to assess freshwater resources using a lumped modeling approach. In a first step, we analyzed 4 years of data (rainfall, discharge and salinity times series) ofthe Port-Miou brackish submarine spring in South France (400 km2). A conceptual model of the aquifer was then designed to differentiate a deep brackish reservoir and a shallower fresh one. Salinity variations at the spring are assumed to be controlled mainly by dilution originating from the fresh water in the shallower reservoir. In a second step, a lumped modeling approach was developed based on the conceptual model to simulate discharge as well as salinity over time. We proposed a reservoir-model to take into account slow and fast components in the shallower part of the aquifer and a saline intrusion in the deeper one. This Rainfall–Discharge–Salinity model was calibrated and validated for two periods of 1.5 years at a daily time step and was also tested to reproduce a multi-annual evolution of the available discharge and salinity time series. Good simulation results were obtained to reproduce water and mass budgets as well as discharge and salinity dynamics during several hydrological cycles. The simultaneous modeling of hydrodynamics and quality data showed the robustness of the model in addition to its easy implementation. Our results led us to propose a new type of seawater mixing mechanism for brackish springs: the dilution type, in addition to the well-known Ventury suction and Head balance types. The application of the lumped model on the Port-Miou brackish spring validated the hydrogeological processes deduced from experimental data, given an initial quantification of the freshwater resources available in such complex brackish karstic aquifers.
- Published
- 2016