Los acuíferos kársticoscasos del País Vasco

Resumen

Karstic aquifers are of a great strategic importance in many regions along the world. These aquifers belong to carbonate formations which have been affected by fissuration and dissolution (karstification) processes. The karstification originates the internal drainage to be hierarchyzed, from the land surface until the flows reach the spring; in fact, this organized heterogeneity is the most important characteristic of the karstic aquifers, marking the difference with the other types of aquifers. In the karstic aquifer the capacity function is located in the rock matrix, which can be more or less permeable, whereas the transmissivity function is assured by the drain network (the conduits). The specific organization of the flows in this type of aquifer determines the methodologies to be used in its exploration. Among these methods are: the analysis of the hydrograph, the tracing tests, the spring chemiographs or the well logs (diagraphies). In this paper some specific applications of these techniques are presented as they have been applied in karstic aquifers of the Basque Country. Finally we want to attract attention on the necessity to value the karstic regions, beyond their interest as water resources reserves.