Convective thermal field reconstruction by ordinary kriging in karstic aquifers (Puglia, Italy): Geostatistical analysis of anisotropy

Abstract

The flow system in fractured aquifers is complex to define. A reliable outline of flow system in such a type of aquifers can be obtained by using natural tracers: among them, temperature demonstrates very effective usuage. Convective thermal fields, resulting from convective disturbance on conductive thermal fields, can be reasonably interpreted like analogues of flow systems. A geostatistical approach by Ordinary Kriging has been applied to groundwater temperature data obtained from temperature logs performed in two fractured karstic and coastal aquifers (Murge and Salento) of Southern Italy. The variographic analysis shows the potential of the geostatistical approach in outlining regional and local scale anisotropies. Moreover, vertical and horizontal Ordinary Kriging temperature estimations at different depths allow recognizing main recharge areas and preferential flow-pathways.