Basin-scale water resource management entails consideration of competing— sometimes conflicting—operational goals and constraints. In the Columbia River Basin, legal, social, technological, and ecological changes suggest a need for a collaborative process to devise and select new water management strategies. Computer modeling for decision support offers a compelling method for using hydrologic simulation models as tools for engaging stakeholders in the process of envisioning, testing, and evaluating novel operational alternatives. This study details the process of developing a daily timestep simulation model of the mainstem Columbia and Kootenay Rivers and integrating the results of a survey to create operational alternatives that implement stakeholder priorities for river management. These alternatives are then modeled over a sixty-nine year period of record and compared to each other and a Base Case scenario using a suite of performance measures that provide information related to flood control, hydropower, instream flow, recreation, navigation, and shoreline goals. A key result of this comparison is that coordinated management of Canadian storage facilities can improve downstream ecological flow objectives at the cost of hydropower generation and certain shoreline objectives at Canadian reservoirs. Distributive and integrative solutions to these tradeoffs are proposed as potential opportunities to reshape the transboundary management regime of the Columbia River Treaty.
