Structural characterization of a carbonate hydrostructures in the Umbria-Marche Apennines

Andrea Tamburini (a)
(a) Department of Pure and Applied Sciences. University of Urbino, via Cà le Suore, 2/4, 62015, Urbino, Italy. E-mail: andrea.tamburini@uniurb.it

This investigation aims to determine the hydraulic conductivity of the carbonate reservoir of SW limb of M. Nerone (Umbria-Marche Apennines) and to identify the patterns of groundwater circulation by using the Kiraly structural-geological method. The results show how the highest values of hydraulic conductivity (kmax ≈ 10-3 m/s) are linked to Calcare Massiccio Formation in the middle portion of karst aquifer, whereas the main direction of conductivity vectors is oriented toward about N210° (SSW). The effective infiltration calculated in the Giordano basin is about 118 l/s, a value rather higher than the mean discharge of the related karst spring (about 70 l/s). This discrepancy seems to be linked at the variation of some structural parameters (like the aperture sizes) with the depth. Therefore, the Kiraly method is a valid approach for estimating hydraulic conductivity values of the rock masses, but only if a shallow geological model is taken into account. For greater depths, method suffers strong limitations.

Carbonate reservoir, joints, hydraulic conductivity