Two major dams, Daechong Dam and Yongdam Dam, are located in Geum River basin. Unlike Daechong Dam built in 1981, Yongdam Dam located in upstream of Daechong Dam is recently completed. However, since recent droughts have accentuated water shortage in this region, it is imperative to improve regional water management planning regarding trade-offs between regional water conflicts associated with limited water resource. The initial filling of Yongdam Dam was delayed due to concerns in that its operation would negatively impact water availability for Daecheong Dam. In addition, there is considerable debate over what values would be most appropriate for instream flows between two dams and below the Daechong Dam. Either instream flow from Daecheong Dam or instream flow from Yongdam Dam would have a significant impact on downstream water quantity and quality of the two dams. The trade-offs between municipal water demands and instream flows are explored in this study. Analyses for this basin were implemented based on "a shared vision model" using the  software environment.