Borehole water-level variations and implications for the subglacial hydraulics of South Cascade Glacier, Washington State, U.S.A.

• Published in: Journal of Glaciology
• Main Author: Fountain, Andrew G.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1994
• Subjects: Journal of Glaciology
• Online Access: http://dx.doi.org/10.1017/s0022143000007383; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000007383

Abstract Boreholes were drilled in South Cascade Glacier to investigate the hydraulics of subglacial water flow. Results indicate that subglacial water pressures are generally close to local ice-overburden pressures and that a subglacial debris layer probably exists. Calculations indicate that the range of hydraulic conductivity of this layer is 10 −7 -10 −4 m −1 . The borehole water levels generally increased during the ablation season and may be caused by a seasonal evolution in the permeability of the debris layer. Water in the debris layer drains to a subglacial conduit, the existence of which is inferred by large diurnal variations in the water level of one borehole. These levels commonly reached the bottom of the glacier, indicating near-atmospheric pressures in the conduit.