ADDRESSING CLIMATE CHANGE UNCERTAINTIES IN THE INTERNATIONAL JOINT COMMISSION'S RIVER BASIN MANAGEMENT MANDATES: THE ST. CROIX RIVER CASE STUDY
This research implements this decision scaling assessment in the St. Croix basin in Northern Maine and New Brunswick – the easternmost land border between the United States and Canada. This work is the first implementation of the Climate Change Guidance Framework for the IJC. Several water level and flow requirements exist in the St. Croix basin: to meet hydropower, environmental, and recreational targets. By taking a bottom-up, decision scaling approach, we assessed how violations of these water level and flow mandates may change as a result of future climate change. We first defined the objectives and critical flow and level thresholds at various points in the basin. We then developed a coupled hydrology-water system model to analyze system performance under different future climate conditions, and implemented a “climate stress test” to assess violations to these critical thresholds. Results from the study was presented to the St. Croix Watershed Board and the IJC commissioners to provide quantitative information for decision making. Future applications of this framework can be useful for other watershed organizations to identify how climate change can uncover vulnerabilities in critical thresholds which affect basin level objectives.