Flow dynamics in a vadose shaft – a case study from the Hochschwab karst massif (Northern Calcareous Alps, Austria)

Karst aquifers are highly vulnerable to contamination due quick water flow through conduits. Their high heterogeneity and the poorly known infiltration effect of vadose zone make quantification recharge processes difficult. This study characterizes storage in upper with almost four years monitoring a permanent stream shaft (Furtowischacht). Its small catchment 4,500 m² is located former glaciated Alpine environment (Hochschwab, Austria). High discharge fluctuations between 0.002 19 l/s, relatively hydrograph recession coefficients, transit velocities 0.0015 2.4 m/s estimated salt tracer experiments indicate dynamic behavior. A fast point open karren dolines could be observed for rainfall events indicates karstified network rapid transmission. Snowmelt periods show only slower component diffuse infiltration. However, condensation within conduit system likely superimposed this signal. lumped-parameter rainfall-runoff model used simulate dual porosity approach. It low volume, which accordance 22 m³ (or 5 mm), deduced from analyses. In contrary, physicochemical parameters argue some capability: 1) After an increase discharge, electric conductivity reacts average delay 50 min; 2) Partly piston can recognized. These amounts may stored partial soil cover alone therefore presence hydrologically significant epikarst layer unclear.