A Model of Basal Hydrologic Networks and Effective Stress Beneath an Ice Sheet
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Subglacial processes that control the water pressure and flow determine the large-scale behavior of the overlying ice by regulating basal resistance. We implement a model in which a steady-state subglacial conduit system is surrounded by fully saturated porous media. We investigate branching in this system at fixed angles of 15 degrees, 30 degrees and 45 degrees to the direction of ice flow and further assess these systems by calculating the hydraulic potential gradient to determine conduit flow path. We solve our governing equations for porous media flow and allow ice infiltration of the pore space to occur at a critical effective stress N infiltration. For low values of N infiltration, ice infiltration of sediment allows these conduits to follow their original paths. Where insufficient ice infiltration occurs, the conduit path instead lies parallel to the direction of ice flow. Our results speak to the importance of incorporating small-scale processes into models of subglacial hydrologic networks.