STORM-EVENT RESPONSES OF FIVE KARST SPRINGS IN THE KAWEAH RIVER BASIN, SIERRA NEVADA, CALIFORNIA
All springs exhibited a distinct pulse of water moving through the system after the storm. However, temperature and specific conductance responses varied between springs. These differences are likely due to differences in both the dominant flow path and recharge component (diffuse vs. direct), as well as differences in geologic controls on the diffuse recharge component. Hydrograph separation and other methods were used to estimate relative contributions of event and pre-event waters discharging from springs, as well as to investigate the longer term responses of each spring as the relative contribution of each component changes over time.
Three response patterns were seen at the springs. Three springs had large and rapid contributions of event water to spring discharge: Big, Mossy, and Alder Springs. Each of these exhibited clear responses in stage, temperature, and specific conductance, indicating direct recharge and flow through conduits. In these springs, this storm pulse moved relatively quickly through the system, and temperature and specific conductance increased towards their initial values following the event. Tufa Springs showed a similar initial large decrease in temperature and specific conductance, but with a continued decrease in conductivity after the initial spike, which we interpreted to indicate a large direct recharge component followed by increasing dilution from relatively rapid diffuse infiltration through overlying glacial sediments. Crystal Cave Spring had a much smaller contribution of event water to its discharge and appears to have a strong input control on recharge at the stream-bed sinkpoint. These results document a range of karst systems within the basin that exhibit a diversity of controls on spring discharge and geochemistry in a mountain groundwater system.