Freeze-Thaw Cycle Effects on Groundwater and Surface Water Interaction Amber KobesUniversity of CalgaryGLGY 699: Seminar Presentation

Outline

1. Introduction

2. Study Area

3. Methodology

4. Research Findings

5. Future Considerations

Introduction

Seasonal fluxes in the water level

Primarily in the shallow Groundwater Bearing Zone (GBZ)

Areas with discontinuous permafrost and seasonally frozen soils vary from continuous permafrost zones and warmer climates

Water can exist as liquid, ice, and vapour

Important for resource management

water redistribution and run-off

Engineering designImage sourced from Ireson, et al. 2013

Interaction: Summer

SW-GW interaction affected by:

lateral and vertical flow

baseflow

infiltration

evapotranspiration

runoff

vadose zone soil moisture (capillary)

Interaction: Winter

SW-GW interaction affected by:

lateral flow

baseflow

evapotranspiration

Baseflow is a source of water >0C

Interaction: Freeze-Thaw

Freeze-thaw cycle influences infiltration

primarily for shallow aquifers

Water and ice will exist in different

pores of the soil

Methodology

Hydrogeology Journal (2013) by Ireson et al.

Irdeson et al. combined a theoretical approach with field studies

Study Area: semi-arid region at Duck Lake, Warman and Outlook

Semi-arid

Topographically driven flow

Focus on freeze-thaw cycles in the vadose zone to provide a

conceptual site model

Movement of Water

Infiltration TypesRestricted: Snowmelt Runoff

Limited: Snowmelt Runoff and Infiltration dependent on temperature and saturation

Unconditional: Infiltration dominant

Infiltration type determines the timing and magnitude of infiltration and runoff

Effects of snow cover

Insulating properties

Atmospheric temperature has less influence

Smaller freezing front

Driving Factor of Freeze-Thaw?

Image sourced from Xie, et al. 2021

Grain size distribution affects freezing-

thawing cycles

Larger pores freeze first and thaw last

As temperatures approached 0C, reductions

in hydraulic conductivity were similar to air-

drying soil curves

Image sourced from Watanabe and Flury 2008

Groundwater Recharge

Snowmelt runoff will generate ponding in local topographic depressions

Ponded water causes ice below depressions to thaw faster than surrounding frozen zones creating Depression-Focused Recharge

Annual variability in Depression-Focused Recharge

Prairie wetland ponds are a primary source of water for aquifers

Isotopic composition is variable between wetland ponds that seasonally form in depressions and ponds having a constant water supply

Image sourced from Hayashi et al. 2003

Groundwater Recharge

Increase in storage in winter through to early spring (~100 mm, Duck Lake)

Reduced evapotranspiration

Slow discharge from surficial aquifer

Groundwater Recharge~60 mm in spring

Water at 0.1C is evidence of complete thawing

Vertical gradient upwards in the Spring and Downwards in the Fall

Baseflow Recession

Recharge from frozen ground and runoff affect methods used to model baseflow

recession

Suggests that frozen ground reduces baseflow in the winter due to reduced infiltration

Important study for areas with an increasing active layer

Further Research Implications

Ineffective monitoring in frozen conditions

How to accurately measure liquid water content?

Gravimetric and neutron probes – cannot distinguish between ice and liquid

Time domain reflectrology – difficult calibration

Estimation of groundwater flow in relation to proportions of net

infiltration vs vertical redistribution is limited

Studies recommended to investigate moisture below the freezing front

How increasing active layers will impact groundwater discharge

Study Findings

Interaction between soil and groundwater was controlled by atmospheric

conditions and topographically driven lateral groundwater flow

Larger pores freeze first and thaw last significantly impacting hydraulic

conductivity

Freezing induced groundwater is affected by:

Initial water table depth

Snow cover

Rate of groundwater inflow

Freeze-thaw cycles impact the water level height in the shallow zone but do

not necessarily reflect a gain or loss of water from the subsurface.

Questions

References

(1) Hong-Yu Xie, Xiao-Wei Jiang, Shu-Cong Tan, Li Wan, Xu-Sheng Wang, Si-Hai Liang, and Yijian Zeng. 2021. Interaction of soil water and groundwater during the freezing-thawing cycle: field observations and numerical modelling. Hydrology Earth System Science. 25. 4243-4257

(2) A. M. Ireson & G. van der Kamp & G. Ferguson & U. Nachshon & H. S. Wheater. 2013. Hydrogeological processes in seasonally frozen northern latitudes: understanding, gaps and challenges. Hydrogeology Journal. 21. 53-66.

(3) McGinn, Sean. 2010. Weather and Climate Patterns of Canada’s Prairies. Anthropods of Canadian Grasslands.

(4) Hayashi, M., van der Kamp, G., and Schmidt, R. 2003. Focused infiltration of snowmelt water in partially frozen soil under small depressions. Journal of Hydrology 270 (3-4). 214-229

(5) Wananabe, K. and Flury, M. 2008. Capillary bundle model of hydraulic conductivity for frozen soil. Water Resources Research 44(12).

(6) Bam, E. K. P., Ireson, A. M., van der Kamp, G., & Hendry, J. M. (2020). Ephemeral ponds: Are they the dominant source of depression-focused groundwater recharge?. Water Resources Research, 56, e2019WR026640. https://doi.org/10.1029/2019WR026640