Characterizing groundwater flow paths in an undeveloped region through synoptic river sampling for environmental tracers. Issue 1 (4th January 2022)

• Record Type: Journal Article
• Authors: Smerdon, Brian D.; Gardner, W. Payton
• Is Part Of: Hydrological processes. Volume 36:Issue 1(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-01-04
• Subjects: baseflow -- environmental tracers -- geochemistry -- groundwater -- groundwater age -- groundwater discharge -- isotope; Hydrology -- Periodicals; Hydrology -- Research -- Periodicals; Hydrologic models -- Periodicals; Hydrological forecasting -- Periodicals; 631.432
• DOI: 10.1002/hyp.14464
• Languages: English
• ISSNs: 0885-6087

Abstract

Abstract: Synoptic sampling of three rivers for a suite of environmental tracers is shown to be an efficient way to gain an understanding of groundwater flow paths for a previously unstudied large area in Alberta, Canada. For regional‐scale characterization, classical hydrogeological techniques are limited by the location and number of groundwater wells. This study demonstrates that rivers can become an easily accessible location to sample the distribution of groundwater flow paths discharging to surface water. Modelling of groundwater discharge to the rivers and groundwater mean age helps generate knowledge of groundwater circulation for a large area, which is useful for conceptual model development and focusing future characterization efforts. Results indicate that the benchland areas in this region, with higher topographic relief, had hydrogeological conditions that favoured deeper groundwater circulation with a modelled mean age greater than 100 years from recharge to discharge. Lower relief areas, which coincide with a transition in bedrock formations in this region, appeared to have much shorter and shallower groundwater circulation. The approach required a field program completed in 5 days and financial budget approximately equivalent to drilling a single borehole and installing a monitoring well. It is concluded that under the right conditions, where few classical observation points exist and knowledge is limited, synoptic sampling of rivers can be used to develop scientifically defensible conceptual models at a comparable scale to regional planning and resource management. Abstract : Synoptic sampling of three rivers is shown to efficiently generate a conceptual understanding of regional hydrogeology when combined with basic physiography and geology information. Analyses of multiple environmental tracers and river transport modelling provided estimates of the spatially varying flux and the mean age of groundwater discharging to rivers. For a region that had not been previously investigated, this approach defined conceptual models at the same scale as regional planning and resource management.