ABSTRACT: Hydraulic data statistics on transmissivity coefficient (T; in m2.s-1) and hydraulic conductivity (k; in m.s-1) were extracted for limestone, dolomite and granitoid rock types from a database of 22,922 wells and hydrogeological boreholes maintained by the Geofond branch of the State Geological Institute of Dionýz Štúr – Geological Survey of Slovak Republic. For limestones, data from 238 boreholes could be analysed, and both dolomites (463 boreholes) and granitoid rocks (96 boreholes) are compared within the paper. Mean coefficient of transmissivity was relatively low for granitoids (6.51.10-5 m2.s-1) and in one order of magnitude higher for limestones (6.16.10-4 m2.s-1), due to permeability enhancement of fissures by karstification processes. The highest observed value of mean transmissivity coefficient, however, was obtained for dolomitic aquifers (1.04.10-3 m2.s-1), what is more than two times higher than T estimated for limestones. Dolomitic aquifers also show the highest median values of hydraulic conductivity (3.21.10-5 m.s-1), in one order of magnitude higher than granitoids (2.10.10-6 m.s-1) and three times higher than limestones (9.45.10-6 m.s-1). The data on hydraulic properties of these aquifer types show lognormal statistical distribution and high heterogeneity. Some particular lithological types were also analysed, bringing new information on the local hydrogeological properties, such as the uniformity of all dolomitic types of aquifers, the lowered permeability for Steinalm and Raming limestones in comparison with other types of limestones. We also assume that the borehole pumping tests dataset results from karstified rocks do not show the real hydraulic properties, but serve as an example of their irregular distribution, especially in the case of limestones, not as much in the case of dolomites.
bibliografický odkaz na článok:
Peter M. & J. Švasta, 2010: Porovnanie odporových hydraulických vlastností granitoidov a krasovatejúcich hornín na území Slovenska.- Podzemná voda ISSN 1335-1052, XVI, 1/2010, 85-102.