Alaska Section, American Water Resources Association

Richard Kemnitz, Alaska Section AWRA Northern-Region Director

I would like to invite you to the September 2001 Brown-Bag presentation by Helen French. Please note this meeting is the second Wednesday in March. We look forward to seeing you, please feel free to bring a colleague to the meeting.


September 12, 2001
Alaska Section AWRA, Northern-Region Brown-Bag Presentation
Alaska Department of Natural Resources, Large Conference Room
Noon to 1300


"Infiltration And Flow In A Heterogeneous Unsaturated Zone During Snowmelt"
Helen French

Dr. Helen K. French (PhD, MSc)
Department of Soil and Water Sciences
Agricultural University of Norway
P.O.Box 5028
1432 Ås
Norway


Abstract

Most of the groundwater recharge in Norway takes place during snowmelt. It is during snowmelt and after heavy rains that the risk of polluting ground water is the greatest. In coarse-grained aquifers the horizontal distribution of ground frost and basal ice can cause focused infiltration, which in turn can influence retention time in the unsaturated zone. The new main airport in Norway, Gardermoen, is situated on such an aquifer. De-icing chemicals, infiltrating during snowmelt, constitutes the largest potential for groundwater pollution in the area. The transport of de-icing chemicals and inactive tracers has been studied in a lysimeter trench, near the airport in south-eastern Norway, during several snowmelting seasons. The infiltration/melting pattern has also been characterised by melting plates and electrical resistivity techniques. Stochastic simulations in a 2D model have been employed, using only simplified boundary conditions on the surface to mimic the effect of basal ice. Electrical resistivity tomography has also been employed to study the flow process during the last melting period.

Figure 1, Figure 2, Figure 3