Groundwater – Surface Water Interactions Discrete Fracture Networks of Bedrock Rivers
Groundwater – Surface Water Interactions in the Discrete Fracture Networks of Bedrock Rivers by Celia Sylvia Cassis Kennedy A Thesis presented to the University of Guelph In partial fulfillment of requirements for the degree of Doctor of Philosophy in Environmental Sciences Guelph, Ontario, Canada Celia Sylvia Cassis Kennedy, June, 2017 Abstract Groundwater – Surface Water Interactions in the Discrete Fracture Networks of Bedrock Rivers Celia Sylvia Cassis Kennedy Advisors: University of Guelph, 2017 Professor Beth Parker Professor Gary Parkin Professor Emmanuelle Arnaud Bedrock rivers exist where surface water flows along an exposed riverbed aquifer, but little is known about their physical and chemical properties. Groundwater and surface water are linked at the streambed interface, leading to shared sustainability issues. The sharing of common pathways into and out of the streambed fracture networks provides opportunity for the exchange of thermal, chemical and biological constituents, affecting water quality and ecosystem health. Alluvial rivers exhibit granular beds and their flow patterns are well understood. Much of our water-resource management decisions are based on alluvial river conceptual models using an equivalent porous media (EPM) approach. Since bedrock rivers are more challenging to instrument, their complex flow patterns have not been addressed in the discrete fracture network (DFN) context, thus, there is a gap in the literature. This is the first study of a bedrock river yielding a field-based conceptual model of the spatio- temporal variability of groundwater fluxes and head differentials between groundwater and surface water in the upper 0.30 m of an intact dolostone streambed. A field site along the Eramosa River, in Guelph, ON, Canada, was developed, where the longitudinally-stepped profile of a bedrock riffle-pool sequence exists within a channel meander.
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