T82 Groundwater-Surface Water Interactions Under Climate and Anthropogenic Change

Tuesday, 27 October 2020
1:30 PM - 5:30 PM
Meeting Rooms

THE ROLE OF EPHEMERAL PONDS IN GROUNDWATER RECHARGE IN THE CANADIAN PRAIRIES

Paper number: T82-15
Program: Technical Sessions
Time: 4:50 PM – 5:05 PM

Authors

Abstract

The Canadian prairies are characterized by a mosaic of uplands and wetlands on the surface, and in the subsurface a sequence of surficial unconfined transmission aquifers, overlying clay-rich glacial till aquitards which are up to 100s of meters thick, with sporadic coarse grained inter-till confined aquifers There is consensus that the relatively shallow (< 50 m) confined aquifers in this environment are recharged with modern water, but the mechanism of recharge is not well understood. Published isotope data are ambiguous, and most researchers have suggested these aquifers are recharged by “depression-focused recharge”, which is to say snow and snowmelt runoff collect in wetland depressions, infiltrate after the soil thaws, and produce groundwater recharge. At our field site, St Denis, Saskatchewan, there is a confined aquifer approximately 30 m below the ground surface. In this study we used physical measurements and stable isotopes to explore the recharge mechanisms to the confined aquifer at St Denis. We propose a refinement to the conceptual depression-focused recharge model of this system, whereby ephemeral ponds are the dominant supply of groundwater recharge. This idea is consistent with all of the physical and chemical observations at our site.

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-359273

© Copyright 2020 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.