Project Components

• Hydrogeology and information system

Data structuring is essential for the NWSAS project whose aim is to optimise all the information compiled in the region to date. The collection of this information is a prerequisite to updating the assessment of knowledge on the basin's resources.
A preliminary analysis showed that all three countries had set about improving or reshaping their own information systems so as to organise disparate data and introduce automatic data processing tools. Emphasis should, however, be given to the fact that the systems now being planned or implemented have the following characteristics:
- they do not accommodate GIS data;
- data is structured in a way that is not always relational;
- the data bases are not connected to the processing tools and, more specifically, to the digital models.
The NWSAS project was anxious to establish a permanent information compilation and updating system which would be run by an organisation from the countries themselves. With this in mind, the approach that was used came from a data model concept that included both the NWSAS project requirements and the specific country needs in order to provide additional guarantees of sustainability. A common core that was used in building up the joint NWSAS data base was derived from this global model.
In sum, the conceptual approach and implementation procedure were based on the following elements:
- Approach based on data -> sustainable system receptive to change;
- Organisational design that takes account of existing structures and facilities;
- Involvement of national experts throughout the implementation phases;
- Choice of tools that are simple and readily useable by all;
- Attention to current and future post-project requirements (structure of joint management).

• Mathematical Model

• Consultation mechanism

The Algerian-Tunisian chotts in the TC constitute the area that is most exposed to salinity. It is also no doubt the region where the aquifer is the most vulnerable, where population density is higher and where pressure on the resource is the strongest. Calculations from the Model clearly show that continuation of the present abstraction rates would lead to additional drawdowns of 30 to 50 meters by the year 2050. This would not be acceptable for the Terminal Complex. The possibility that the aquifer would receive water percolating from the chotts would include a fatal risk of salinsation.