The Hydrology of the Castleguard Karst, Columbia Icefields, Alberta, Canada^∗

Abstract

The Castleguard area is a classical alpine karst, characterized by high relative relief and partly overlain by glacier ice. Access to the subglacial aquifer is possible via a relict cave. Drainage of the glacier bed occurs at both the conduit and diffuse flow scales. The contemporary hydrology is dominated by supraglacial meltwaters, which have been traced into the groundwater system. More than 100 springs in the Castleguard Valley constitute a hierarchy based on size and relative elevation. Status within the hierarchy is demonstrated by behavior as “underflow” or “overflow” springs. Floods emerging from springs perched 300 m above the valley floor are an overflow probably derived from the Saskatchewan Glacier. Quantitative dye tracing has revealed complex spring behavior, largely in response to changes in the spatial distribution of recharge. The aquifer appears to be mature, with a well-developed conduit network. The numerous springs are a product of disruption by glaciation; disturbance appears to be the major effect of glaciers upon this karst aquifer. Ice may be drained karstically where sufficient pressure gradients exist; decreased ice velocities and erosion rates are possible effects of underlying karst upon glaciers.