Hydrogeologiczne cechy warstw krośnieńskich centralnej depresji karpackiej

Abstract

Przeanalizowano wpływ wykształcenia litologicznego dolnych warstw krośnieńskich na ich przepuszczalność i wodonośność. Stwierdzono statystycznie istotne różnice między wodonośnością ogniwa łupkowo­piaskowcowego i ogniwem piaskowców gruboławicowych. Określono potencjalne wydajności studni wierconych w dolnych warstwach krośnieńskich. Uzyskane wyniki porównano z wodonośnością i przepuszczalnością warstw magurskich. Wyniki badań opracowano przy zastosowaniu analizy statystycznej.THE HYDROGEOLOGICAL CHARACTERJSTICS OF THE KROSNO BEDS IN THE CENTRAL CAJU'ATHIAN DEPRESSION Analysis of the Lower Krosno Beds, presented in the paper, allowed for revealing a certain relation between their litho logic features and both their permeability and water storage capacity. Furthermore, the water storage capacity of the Krosno Beds occurred to be visibly lesser if compared with that of the Magura sandstone unit. This refers to both the Krosno Beds considered as a whole and their particular members as well. Variability in the storage capacity was also analysed in terms of depth. Thickness of permeable zone within the Krosno Beds, reaching 40 m at Besko, occurred to be diminished twice in comparison with the Magura Sandstones. Permeability of the Krosno Beds is analoguos to that of the Magura Sandstones; it reaches its extreme value at the summit parts, the medium one at the sides, and the lowest in the valley bottoms. Value of 1.4 x 10-6 m/sec is a medium permeability of the Krosno Beds in the zone from land surface to depth of 20 m, and 2.4 x 10-7 m/sec is a representative one for the depth interval from 20 m to 40 m. In both the cases the Krosno Beds reach permeability by one order lower than that of the Magura Unit. Based on the study of water storage capacity the potential well yields were calculated. When considering the water saturation in total thickness of both permeable zones mentioned above, then the potential yield of individual well installed to the depth of 20 m and pumped at potential drawdown of 20 m can reach 10 cu mph; another well installed in shale·and·sandstone complex to depth of 40 m is expected to yield 2.4 cu mph at 30 m drawdown respectively.