This case study describes how the Okanagan Basin Water Board and various partners initiated the Okanagan Water Demand and Supply project to support water planning, allocation, licensing and engineering decisions in the Okanagan system. The project developed science–based computer models of the water demand and supply systems in the basin, taking into account the impacts of climate change, population growth and land use. This project received funding from the BC Regional Adaptation Collaborative program. Project materials include a summary report, local government guide, online viewer to access the data and a related video tutorial.