The Republican River Basin is an important region for the states of Nebraska, Colorado and Kansas (the States) that includes highly productive agricultural lands, large reservoirs with recreational and wildlife habitat features, and established communities that rely on the agriculturally-driven economy and the water supplies that sustain it. The water management issues in the Republican River Basin are extremely complex and involve a long history of stakeholder involvement and activities. Declines in groundwater levels and streamflows have and continue to be widespread throughout the Basin, creating competition for limited water supplies and litigation. This Basin Study provided an opportunity for the three States to work toward overcoming some of these challenges by coordinating with the Bureau of Reclamation (Reclamation) to identify and evaluate alternative management and infrastructure changes that might benefit water users within the Basin, while strengthening the local economy and protecting environmental resources. The inclusion of future climate change scenarios provided an indication of the robustness of the system under climate variability, such as how the reservoirs and canals might operate and adapt under severe drought conditions, and how physical and operational changes may impact local economic benefits relative to costs. Because of the legal, physical, and institutional complexity of water operations in the Basin, the models developed under this Basin Study may be especially important in helping the States investigate relationships between management decisions and physical responses to the Basin water supply. The achievements made through this Basin Study are owed to the high levels of professionalism and collaboration displayed among Basin Study partners. Coupled with recent and ongoing negotiations and agreements, sustainable, win-win solutions to solving the Basin's complex water supply issues appear promising.