SNOWMELT INFILTRATION AND STORAGE WITHIN A KARSTIC ENVIRONMENT, VERS CHEZ LE BRANDT, SWITZERLAND

With increased global temperature, the hydrologic cycle could undergo significant alteration including possible reductions in seasonal snow cover and shifts in amount and type of precipitation. Alterations in these parameters would invariable affect the volumetric and temporal distribution of groundwater recharge, particular in cold-regions. With the aim of extending the minimal current knowledge of cold season recharge processes to karstic aquifers, the present study examined the presence and magnitude of subsurface flow as it relates to inter-winter snowpack melt within a karstic environment. This was accomplished by evaluating the relationships between site lithology, climate, precipitation, snowpack outflow, soil pore water, vadose zone and watershed outflow. Data indicate that the quantity and duration of meltwater input at the soil surface seems to have a governing role on flow within the soil and epikarst. Extended influxes associated with prolonged snowmelt enable the saturation of underlying clays, and the consequent formation of a shallow perched lens. Thus, in karstic watersheds overlain by calcareous loess, clay layers within soil, and not the epikarst, may serve at the mechanism impeding infiltration and shallow lateral flow within these watershed may be occurring in shallow soils and not within the epikarst network as previously postulated. Hydrograph analysis of a vadose zone drainage point and watershed’s spring, show that the former has a governing role in the latter. This implies that a fundamental understanding of soil structure and distribution is critical when assessing recharge to karstic aquifers.