ASSESSING GROUNDWATER RESOURCES IN A MOUNTAIN SETTING

Although most work in mountain hydrology has assumed negligible aquifer input, this may not be the case in many systems: mountain aquifers can provide significant temporal storage of water. Developing an understanding of these systems is essential for managing these resources. However, physical characterization of these systems can be challenging, with many occurring in remote areas where the use of typical methods for assessing aquifer parameters is difficult or impossible. Analyses of surface river discharge data, coupled with available surface geology data, can provide initial insight into and quantification of the extent and role of mountain aquifers within river systems. These methods were applied to available river discharge data from seven sub-basins in the Southern Sierra Nevada of California to characterize the role of groundwater in basin hydrology. Hydrograph characteristics of each drainage basin were compared with areal extents of various bedrock and non-fractured rock aquifers to estimate their role in maintaining baseflow discharge in the surface rivers. These data suggest that basins with significant amounts of karst have a substantial long-term storage component to the system. These data also suggest that basins with significant amounts of unconsolidated material (glacial deposits, talus, and alluvium) show a similar trend in groundwater storage.