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Accueil du site → Doctorat → Espagne → 2018 → Contribución de las técnicas hidroquímicas, isotópicas e hidrodinámicas a la caracterización de acuíferos carbonatados y su relación con la red de flujo superficial. Aplicación al acuífero de Alcadozo (cuenca del Segura)

Universidad Politécnica de Cartagena (2018)

Contribución de las técnicas hidroquímicas, isotópicas e hidrodinámicas a la caracterización de acuíferos carbonatados y su relación con la red de flujo superficial. Aplicación al acuífero de Alcadozo (cuenca del Segura)

Hornero Díaz, Jorge Enrique

Titre : Contribución de las técnicas hidroquímicas, isotópicas e hidrodinámicas a la caracterización de acuíferos carbonatados y su relación con la red de flujo superficial. Aplicación al acuífero de Alcadozo (cuenca del Segura)

Auteur : Hornero Díaz, Jorge Enrique

Université de soutenance : Universidad Politécnica de Cartagena

Grade : Doctoral Tesis 2018

Résumé partiel
The increase of water demands in arid and semi-arid areas and the climate change scenarios that project a gradual decrease in rainfall in our latitude, augment the need to adequately study all aquifers in an area, even those littleexploited and known, and evaluate the resources they can contribute to the whole water resources system. In this context, the general objective of this thesis is to demonstrate that the use of multiple characterization techniques and hydrogeological research at different spatial scales, and the integration of the information they all contribute, is a conclusive methodology to stablish solid conceptual models on large carbonate aquifers of which there is little information. Another main objective is to advance in the integration of recharge estimation methods in order to improve the reliability of the values they provide, their spatial variability, and the information on the processes involved. The study area is the Alcadozo aquifer, which is located in the centre of the Albacete province and is part of the External Prebetic domain of the Betic Range. With an area of 509 km2, the aquifer is part of the Alcadozo Groundwater Body (GWB), which is formed by Jurassic (Dogger and Lias), Lower Cretaceous and Paleogene materials. The Jurassic limestones and dolomites constitute the main permeable formations, which overlay lowpermeability Triassic materials and form the aquifer studied. The area is characterized by a complex geologic structure consisting of a succession of folds and thrusts. The climate is semi-arid Mediterranean except in the western sector, where there is a marked continental influence. The relief is rugged (altitude between 944 and 1577 m a.s.l.) and display strong rainfall (600 mm to 360 mm from W to E) and temperature gradients (12 ºC in the W to 17 ºC in the E). The Mundo River is the main surface drainage axis. It is a calcareous Mediterranean mountain river and a tributary of the Segura River. Groundwater is almost unexploited in most of the GWB except in the eastern area, where there is irrigated agriculture. The general objective of the thesis has been split into several specific objectives : to define the regional groundwater flow ; to estimate recharge rates and their spatial distribution at regional scale, as well as the uncertainty ranges of the estimates ; to characterize groundwater and surface water hydrochemical and isotopic composition ; to identify the main solute sources and deduce the most relevant hydrogeochemical processes at regional scale ; to analyse the hydrodynamic impact that drilling of the Talave tunnel had on the groundwater flow and to know the current hydrodynamic relationship with the rock massif ; to develop a conceptual hydrogeological model on the functioning of the aquifer and to validate it with groundwater flow numerical modeling. The methodology used to achieve these objectives consisted in the application Spring and river flow rates and borehole and wells piezometric levels have been used to know the groundwater flow network pattern at regional scale, the magnitude of recharge and the location of recharge and discharge areas. Those data also allowed understanding the hydrodynamic behaviour of the two man outlets of the aquifer, the Ayna and Liétor springs. A particular survey was carried out in the Talave tunnel to locate and sample the main groundwater leaks inside the tunnel. The relationship between the Mundo River and the aquifer has been studied by means of water balances, chloride mass balances and radon activity balances. Interannual recharge to the aquifer has been estimated for the Ayna and Liétor springs catchments by modelling the Soil Water Balance (SWB), and for the whole aquifer surface by Atmospheric Chloride Mass Balance (ACMB). The confidence intervals of the recharge values have also been estimated, as well as the consistency of both methods. To perform the hydrochemical and isotopic studies, some 150 water samples has been collected from rivers, springs, wells, boreholes and the main leaks inside the Talave tunnel.

Mots Clés  : Acuíferos Aguas subterráneas Túneles Aguas superficiales Hidrogeología

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Page publiée le 25 février 2019