Hydrogeological research in boreholes at the test site in Melechov massif

 

Lenka Rukavičková

Geoscience Research Reports 40, 2007 (GRR for 2006), pages 212–215

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Abstract

Hydraulic properties of fractured granite massifs were studied at the test site in Melechov massif in Českomoravská vrchovina (Moravian Highs). These sites comprise four types of granite. Altogether 127 hydrodynamic tests in isolated borehole sections were carried out in five boreholes. The depths of the boreholes were from 150 to 200 m. Responses of hydraulic pressure on hydrodynamic testing in a selected borehole were monitored in several isolated sections of adjacent borehole using a multipacker system. The obtained data set has provided new information about hydraulic properties of fractured granites characterized by a very small permeability of the rock matrix. This set includes piezometric levels of fracture systems, vertical profiles of the hydraulic conductivity, identification of main conductive fractures and their interconnection among boreholes in the rock space. Fractured granite massifs have a wide range of hydraulic conductivity depending on the amount and character of the fractures. The open fractures in faulted zones have hydraulic conductivity 10 -5 m . s-1 on average, whereas the compact granite and granite with closed fractures or with fractures filled with secondary minerals have hydraulic conductivity in 10-10 m . s-1order.