THE ROLE OF KARST GROUNDWATER IN A SNOWMELT-DOMINATED HYDROLOGIC SYSTEM: THE KAWEAH RIVER, CALIFORNIA, USA
The river and springs have statistically similar baseflow recession coefficients (F1, 63= 2.799, p= 0.099) and river waters in basins with significant karst are geochemically similar to the karst springs within each basin. The percentage of total discharge that is derived from karst groundwater varied between forks depending on the amount of karst present, and between years, depending on precipitation. Measured contributions by karst springs varied from 3.5% to 16% during high flow and 20% to 65% during baseflow between forks and 3.5% and 6% during high flow and 20% and 36% during baseflow between years for the entire river. Modeled results were comparable to direct measurements.
These results show that karst aquifers may be the single most important non-snow storage component in the Kaweah River basin: mapped karst represents just 1.4% of the surface area, but water stored in karst represents a much larger portion of river discharge during both high flow and baseflow conditions. This suggests that when karst aquifers are present in mountain systems, even as a spatially small component, they can be a large component of the hydrologic system and provide substantial water storage.