WHEN THE FOGGARAS OF ADRAR WAKE UP!

Abstract

In the areas of Touat, Gourara and Tidikelt, ancient inhabitants have exploited the lowlands of the Tademait plateau which offer topographic and hydrogeological conditions allowing the gravity exploitation of the groundwater on lower lands and without energy or pumping techniques. This ensured permanent water resources that allowed human presence in such hostile conditions over the centuries. This catchment technique has shown its secular effectiveness in the sustainable exploitation of the water resource. These foggaras still irrigate more than 50% of the irrigated area in the Touat, Gourara and Tidikelt and contribute to the stability of the oasis society. The introduction of  boreholes with powerful pumps intended for different uses since the 1980s had negative impacts on the traditional irrigation system, and consequently on the oasis ecosystem, by drying up of 1468 foggaras out of a total of 2283 foggaras in the study area. This situation requires doing a scientific research aimed at preserving the foggaras of the study area, which still have an important economic and ecological resource to the oasis people. In this context, we aim through this research to shed light on the current situation of the system and to offer the specialists of the field as well as the decision-makers a tool allowing a better water resources management in this area. This paper developed on the basis of a big set of data and field surveys on foggaras and boreholes in the area. It is organized as update the general context of the study area and the CI aquifer. In order to fully understand the foggara system and the problem of ground water resources exploitation in the catchment areas, we produce and analyze digital maps according to the problems encountered in the field. They are particularly related to hydrogeological and piezometric factors. In this context, we have drawn up a map of the water table drawdown. Finally, we show the case of the oases of Bouda which experienced, in 2017, a rise of the water table due to the abandonment, in 2016, of five (05) boreholes intended for the supply of drinking water and located in the catchment area of the foggaras. We show through this example the impact of boreholes, often installed without prior study, on foggaras. By using the results of this paper, based on the hydrogeological and piezometric maps made for the years of 2007 and 2016, we have been able to realize the drawdown map between these two dates. The map shows an explicit causality with the foggaras drying phenomenon. In the case of Bouda foggaras, we make explicit the interference between boreholes and foggaras and the sensitivity of the latter to the least drawdown in their catchment area. This shows the interest of reviewing the current aquifer management plan in the light of recent transformations in the area.