Developing tools for managing hydrogeological data in a semi-arid region: the case study of Oulmès (Morocco)

Data and information required by hydrogeological studies are various and complex such as geology, topography, climate, hydrological and hydrogeological raw or pre-processed data. All these data need to be managed, and this can be done in a structured database. A (GIS-managed) hydrogeological database has been developed previously by the Hydrogeology Group of the University of Liège (Gogu et al., 2001) in order to capture, store, edit, query, update and display geographically referenced hydrogeological data. The development of this geo-relational database was constrained by a maximum storage of data with a minimum data redundancy, reduction of storage memory capacity and optimum ‘retrievability’ of information for further analysis. In recent years, the use of Geographical Information System (GIS) has grown rapidly in groundwater management and research. GIS is now widely used to create digital geographic databases, to manipulate and prepare data as input for various model parameters, and to display model output. Coupling GIS with this hydrogeological database provides a powerful tool. This GIS-managed hydrogeological database has been also developed for vulnerability-assessment techniques and numerical modelling for groundwater flow and contaminant transport studies. As well as linking between database and GIS, the design of coupling database with process-based numerical models was also performed. This methodology has been applied, in a semi-arid region: the "Oulmès plateau" located in the Mid-Atlas (Morocco). This study has led to a detailed hydrogeological map at the scale of 1/25000. First, data were collected from existing databases, studies and maps as well as through new field measurements. These data came from numerous and various sources and in different formats (paper or digital diagrams, images, spreadsheets…). After validation, it has been encoded in the hydrogeological database. Because data are geo-referenced, it can be easily represented on the map within GIS-software. The hydrogeological map displays several layers of information as topography, hydrogeological units, hydrographic network, wells, piezometers, isoline of piezometric heads