Resumen de An evaluation of physical and chemical discharge parameters at a spring that drains the epikarst: Kentucky, USA
Physical and chemical parameters measured at a spring discharge can be used to infer recharge type to the epikarstic catchment that recharges a spring. This study showed that conductivity, temperature, and stage, measured by a digital datalogger, can be used to determine the type and percentage of recharge, seepage versus concentrated, that contribute to a spring�s discharge point. Ewers Alley Spring is a small perennial spring which drains a groundwater basin developed solely within the epikarst. This spring was fitted with a digital datalogger to determine if changes in temperature, conductivity, and stage, which have been used to characterize springs that drain mature karst basins, can also be used to characterize recharge to a basin that is charged solely from groundwater stored in the epikarst. The study determined that changes in temperature, conductivity, and stage, in response to precipitation events, are reliable measures in determining recharge type to a drainage basin located solely in the epikarst. Changes in temperature, conductivity, and stage revealed that Ewers Ally Spring is dominated by seepage recharge conditions, and at baseflow, the groundwater in all probability is saturated in respect to calcium carbonate. During wetter periods of the year, when flow from the epikarst is greater, groundwater discharge from the spring is prone to be undersaturated in respect to calcium carbonate; this is due to the influx of stormwater into the epikarstic system. In spite of the fact that seepage recharge conditions are dominant, numerous vertical conduits and open channels present at this location can transmit water rapidly into the system. This results in quick-flow conditions that can travel quickly to groundwater springs in the basin. However, the effects of quick-flow conditions on Ewers Alley Spring, as a result of concentrated recharge, are limited due to the predominance of the overlying soil cover and the restricted radius of influence of open pits and shafts. Normalized Base Flow per unit discharge applied to Ewers Ally Spring calculates a spring recharge area, or basin size of 29,541 m2.
