Une gestion plus active des réservoirs d'eau souterraine pourrait contribuer à mieux résister aux sécheresses

Abstract

Click to increase image sizeClick to decrease image sizeThe exploitation of the natural underground water tables has been limited, in most cases, to collecting part of their natural flow under the double constraint of the productivity of the works and of the conservation of the emergences from which the flow of the surface waters depends. As such, little benefit has been gailled from the aquifer reservoirs, whose volumes are indeed varied but often considerable, if only by taking advantage of the spontaneous regulating function of their seasonal and pluriannual fluctuations - except for the "evidenced overexploitation" cases which constitute a form of management to be rejected. In view of the increasing risk of water scarcity during droughts, there is a need for a new strategy for the exploitation of the undergrownd water, that would imply a more active use of that resource wherever possible. The feasibility of such operations depends of course on the knowledge of the underground reserves, on the direct costs of temporary production, on the socio-economic acceptability of the impacts on conventional exploitations and finally on the external effects (depletion of sources) and onthe potential for compensation. Within a more integrated approach of the water management, a larger, sensible and controlled use of the regulating capacities of the aquifers could enable the effects of droughts to be compensated for, in addition to the pluriannual management of large surface reservoirs. This would take place in a more competitive manner considering the fact that sites for dams are becoming rare and that the stilting of reservoirs reduce their capacity.