Impact of Changing Snow Cover and Frozen Ground Regimes on Groundwater Recharge

Current Students Working on this Project
Katrina Rabeler, graduate student

Research Topics
Freeze and thaw cycles
Snow cover
Frozen ground
Groundwater
Climate change

Research Methods
Retrospective analysis
Statistical analysis
Numerical modeling

Conceptual model of how midwinter melt and subsequent freezeback events can create nearly impermeable frozen soil, reducing infiltration and groundwater recharge and increasing overland flow in subsequent melt events. (a) Snowmelt from midwinter melt events can infiltrate and cause discrete recharge events when soil is minimally frozen and has low moisture content. (b) Midwinter melt events can also increase soil moisture content and leave the ground exposed to subsequent cold periods, or freezeback events, creating a deep soil freeze. (c) In subsequent snowmelt events, the nearly impermeable frozen soil layer can reduce infiltration and recharge and increase overland flow.

Research Description

How do periods of mid-winter snowmelt affect the hydrologic cycle? How will this be impacted by climate change? The objective of this project is to determine the extent to which changes in freeze and thaw cycles alter groundwater recharge.

In the Midwest, development of a seasonal snowpack leads to groundwater recharge associated with the spring snowmelt which often accounts for a sizable percentage of the annual groundwater recharge. Mid-winter snowmelts are becoming more common with a warming climate and may shift a portion of this groundwater recharge to earlier in the year. However, loss of this snow cover also has a major impact on the soil thermal regime because the snow acts as an insulating layer. If cold but snow-free conditions prevail after a mid-winter melt, the potential exists for quick refreezing of soils in a nearly saturated state, resulting in low permeability frozen ground. Additional snow accumulation and subsequent melt is unlikely to result in infiltration due to the low permeability frozen ground, but rather will runoff the landscape as overland flow.

Understanding the multifaceted feedbacks between snow cover, frozen ground, infiltration and groundwater recharge are critical for predicting the ways in which groundwater resources will be affected by climate variability and changes in environmental conditions.

This project is funded by the Wisconsin State Water Resources Research Institute Program through the UW Aquatic Sciences Center. This material is based upon work supported by the U.S. Geological Survey under Grant/Cooperative Agreement No. G16AP00092. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the opinions or policies of the U.S. Geological Survey. Mention of trade names or commercial products does not constitute their endorsement by the U.S. Geological Survey.

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