Groundwater capacity of a flysch-type aquifer feeding springs in the Outer Eastern Carpathians (Poland)

Abstract

The aim of the study is to assess the capacity of the flysch aquifer feeding springs in the Outer Eastern Carpathians using spring recession curves. The four selected springs are located in an area generally believed to be poor in groundwater. However, the selected springs were characterized by remarkably high average discharge of 3.2-9.6 L s^{-1}. Recession coefficients were estimated which enabled an aquifer capacity and groundwater residence time assessment. Despite similarities in elevation, precipitation, and lithology in the study area, a substantial variation in the recession coefficients and aquifer parameters was found. The average aquifer capacity of groundwater subsystems strongly varied in the small study area (4.9-49 m^{3} × 10^{3}). The mean groundwater residence time varied from 11 days to 50 days depending on the volume of groundwater drained by the springs. Differences in discharge, recession coefficients, groundwater capacity, and residence time were related to recharge areas of different size. Simple relationships between the topographic catchment areas of springs and their hydrologic parameters can become altered by local structural features: faults and fissures. The study demonstrates that tectonically produced structures may facilitate a larger supply of groundwater and the occurrence of high-discharge springs in a given area