K-water has led national policymaking in South Korea through a master plan established in 2015 to raise national awareness on integrated water resources management (IWRM). It has promoted leading pilot projects as a short-term plan. Since the construction of the initial dam on the Seomjin River in 1928, inefficient water management has persisted. There was a jumble of agreements, treaties, regulations, and various institutions that could not keep up with the changing conditions in dam operation and water use caused by the construction of the new dam and auxiliary spillways on the river. Also, there were four agencies designated as dam usage rightholders: Two more were added to the original two dam licensees. Accordingly, the initiative project established a consensus on the need to streamline dam operations and promoted deriving social agreements through a council composed of the field-level departments of each water management agency. After government mediation, dam management regulations were revised to determine adjustments in the dam usage rights and the basic priorities in water use. This IWRM pilot model, which promotes the rational use of a dam by multiple users, successfully satisfied each stakeholder’s agreed-upon rights in 2019, the first project year.