Moeller, Carolyn A., 2004. Modeling the groundwater flow system along a flow line of the Scandinavian Ice Sheet. [M.S. thesis] University of Wisconsin-Madison, 61 p. (04-6)

Basal water pressure and flow patterns are significant factors in controlling the behavior of an ice sheet, because they influence ice sheet thickness, stability, and extent. Water produced b y basal melting travels toward the ice margin through the groundwater system, and if present in sufficient quantities, as sheet or channelized flow. The flow of subglacial groundwater along a flow line of the Scandinavian Ice Sheet is examined using a two-dimensional MODFLOW-based profile model, assuming that groundwater flow is parallel to the ice flow line. The study area lies in the western fjords region in southwestern Norway. The modeled flow line runs through Nordfjord, from the modern-day glacier Jostedalsbreen, through the fjord, and westward to the shelf edge. Meltwater input to the groundwater model comes from a two-dimensional, time dependent, thermomechanically coupled ice flow model that runs along the same flow line. Hydraulic conductivities and sediment thickness are input to the groundwater model manually, but are also used in sensitivity experiments. Model results show that the sediments could not have transmitted all of the meltwater out of the fjord during times of ice advance and retreat, as well as at the maximum position at the edge of the continental shelf. Model runs for retreat phases also include a treatment of additional surface recharge that greatly impacts the bed conditions, which could explain non-climatically driven margin readvances during the overall retreat phase. Excess water could have been evacuated from the system via sheet flow or a drainage network, keeping porewater pressures at reasonable levels.