Author
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Sharratt, Brenton |
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Submitted to: International Journal of Water
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/27/2008 Publication Date: 9/9/2009 Citation: Sharratt, B. 2009. Groundwater recharge during spring thaw in the Prairie Pothole Region of North America, Int. J. Water, Vol. 5, No. 2, pp.100–108. Interpretive Summary: Ground water in the Northern Plains of the US is replenished by snowmelt. Snowmelt accumulates in landscape depressions and forms temporary ponds; this water enters groundwater systems by percolating through soils that appear to be frozen. I found that water in these temporary ponds does not quickly permeate through a frozen soil matrix, but instead rapidly permeates through large unfrozen conduits or thawed soil beneath the landscape depression. Knowing when surface water infiltrates soil in the spring can help farmers plan field operations as well as aid engineers in managing stream flows and water resources in cold regions. Technical Abstract: Snowmelt collects in landscape depressions and appears to replenish groundwater in the Prairie Pothole Region of North America while the soil is frozen. Little is known, however, about the physical state of the soil at the time of recharge. Depth of snow, surface water, water table, and frozen soil were measured within a 2-ha landscape depression in Minnesota during spring thaw in 2000 and 2001. The water table rose by at least 1 m within 24 h after a pond formed within the landscape depression as a result of snowmelt. In 2000, unfrozen conduits (surface area of 0.1 to 0.4 m2) were found that protruded through the frozen soil underlying the pond. In 2001, the soil profile beneath the pond was thawed. Recharge of groundwater after snowmelt is a seemingly localized process where surface water infiltrates via unfrozen conduits or soil matrix beneath an ephemeral pond within a prairie pothole. |
