Internal structure and hydrological functions of an alpine proglacial moraine

Abstract Understanding groundwater processes in alpine watersheds is critical to understand the timing of water release and late‐season stream flow for both headwater and downstream environments. Moraines and talus features can play an important role in groundwater flow and storage processes in alpine watersheds, but neither process is well understood for these features. We examined the complex hydrogeological environment of a partially ice‐cored moraine in the Lake O'Hara watershed in the Canadian Rockies. Electrical resistivity imaging (ERI) and seismic refraction tomography delineated regions of buried ice and frozen and unfrozen moraine material. Seismic refraction data also clearly indicated the depth to bedrock, which varied primarily due to the thickness of the overlying moraine material. Water levels in a lake and several tarns on the moraine responded differently to inputs of rain, snowmelt, and glacier melt, indicating the different degree of hydrological connectivity of these features to the groundwater flow system in the moraine. Such differences reflect the effects of bedrock topography and the location and geometry of buried ice. Ground‐penetrating radar images and ERI indicated regions of perched groundwater and focused infiltration. The location of these regions appears to be controlled by buried ice. All geophysical and hydrological data suggest that a relatively thin (<5 m) layer of saturated sediments and/or fractured bedrock likely provides a major flow system within the moraine. Copyright © 2011 John Wiley & Sons, Ltd.