Science et changements planétaires / Sécheresse


Design of a piezometric monitoring network for the North Western Sahara Aquifer System Volume 18, issue 1, Janvier, Février, Mars 2007


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École nationale d’ingénieurs de Tunis (Enit), Laboratoire de modélisation en hydraulique et environnement, BP 37, Le Belvédère, 1002,Tunis, Tunisie, Centre de recherches et des technologies des eaux, Laboratoire de géochimie et physico-chimie des eaux, BP 273, Soliman 8020, Tunisie

The database of the North Western Sahara Aquifer System (NWSAS) is composed of 7,600 wells, among which 2,761 have a piezometric value related to the “Continental Intercalaire” or the “Complexe Terminal”. This number is reduced to 1,069 when at least two piezometric measurements are required. This population is subjected to a series of checks and filters in order to eliminate the maximum of meaningless values. A characteristic of the NWSAS is that instead of having a true piezometric network, only a set of disparate piezometric information is available. A reference network is therefore identified and built up by analysing, regrouping and filtering data, the final result being a network composed of 73 wells. A certain number of indicators for characterizing and evaluating the quality of that reference network are then proposed: space cover, monitoring of the extraction, control of drawdown and sustainability of the network wells. These indicators are but so many clues to be taken into consideration for a knowledgeable consolidation of the network.