The Athabasca River Basin faces challenging tradeoffs between energy produc- tion and water security as climate change alters the seasonal freshwater supply and water demand from the oil sands mining industry is projected to increase. Ef- fective water management will depend on a physical understanding of the scale and timing of water supply and demand. This dissertation aims to synthesize the impacts of water withdrawals and climate change on streamflow in the Athabasca oil sands region, in order to develop a scientific basis for the management of water resources. The combination of a land surface process model and a hydrological routing model is used to evaluate the influence of water withdrawals and climate change on streamflow under a variety of different scenarios, and to evaluate the adaptation options.
Climate warming is projected to be the primary driver of future streamflow availability, with little influence from direct water withdrawals. Seasonal patterns that show a decline in summer flows and an increase in winter flows are con- sistent with the response of a snowmelt-dominated basin to warming. Increases in the frequency of low flows that are below a threshold of maximum environ- mental protection suggest that daily bitumen production could be interrupted by up to 2-3 months a year by mid-century. It is also projected that water storage will be required to supplement river withdrawals to maintain continuous bitumen production under the impacts of future climate warming. Based on the model results, a range of water management options are developed to describe the poten- tial tradeoffs between the scale of bitumen production and industry growth, water storage requirements, and environmental protection for the aquatic ecosystems. This physically-based assessment of future water tradeoffs can inform water pol- icy, water management decisions, and climate change adaptation plans, with ap- plicability to other regions facing trade-offs between industrial development and ecosystem water needs.