Groundwater – Surface Water Interactions in Mountain Environments: Comprehending Heterogeneity

Jeffrey M McKenzie, McGill University, Earth and Planetary Sciences, Montreal, QC, Canada, Ryan Gordon, Syracuse University, Syracuse, NY, United States, Devin Cairns, University of Lethbridge, Lethbridge, AB, Canada, Laura Lautz, Syracuse University, Syracuse, United States, James Michael Byrne, University of Lethbridge, Geography and Environment, Lethbridge, Canada and Bryan G Mark, Byrd Polar and Climate Research Center, The Ohio State University, Columbus, OH, United States

Contact First Author: Jeffrey M McKenzie; jeffrey.mckenzie@mcgill.ca

Previously Published Material: A subset of the Cordillera Blanca research was presented at AGU. The Blanca research is in review with J. Hydro. The DEM analysis research is on the cusp of being submitted to a journal.

Abstract ID#: 36703

 

English Abstract:
In glaciated mountain catchments, groundwater is critical in maintaining surface water flows at mid- to high-latitudes during winter and in low-latitudes during the dry season. In these systems, groundwater-surface water interactions are difficult to characterize due to the complex and heterogeneous nature of the hydrogeology. We present results from two groundwater – surface water studies that quantify the magnitude of these interactions and attempt to understand the role of spatial heterogeneity.

At a headwater and mid-valley site in the Cordillera Blanca, Peru, tracer measurements of stream and spring discharge were combined with synoptic sampling of water isotopic and geochemical composition to quantify streamflow contributions from different groundwater reservoirs. At the headwater site, groundwater supplies approximately half of the dry-season stream discharge across a small meadow, with most originating from an adjacent alluvial fan and little (6%) from the meadow itself. At the mid-valley site, with more extensive meadows, groundwater is a large component of streamflow. Although, the most focused inflow of groundwater occurred across a moraine between two meadows (200 L/s or 18% of average discharge). Heterogeneous features, such as valley-crossing moraines and alluvial fans, demonstrate the heterogenous nature of groundwater – surface water interactions.

In the headwaters of St. Mary River Watershed in Glacier National Park, Montana, we have applied an automated geomorphometric model to a 10-m DEM in order to identify the approximate spatial distribution of geomorphic features, considered to represent the subsurface geology, and to delineate each of these features based on relative hydrostratigraphic differences (e.g. glacial depositional features, bedrock outcrops, periglacial landforms, etc.). The results further demonstrate the complexity of the underlying hydrogeologic system and how it may affect subsurface storage and residence times.

Back to: Groundwater-Surface Water Interactions I