Study on the Evaluation of the Water Supply Capacities of Multipurpose Dams

Recent climate change has significantly affected water quality and led to water shortages. Accordingly, this study re-evaluated the water supply capacity of the Daecheong Dam and calculated the additional water supply available to determine the feasibility of meeting the target water quality for the Mihogang River. The Mihogang River is directly influenced by the Daecheong Dam, which is situated in the middle section of the Geumgang River. A reservoir simulation was conducted over approximately 40 years (from 1983 to 2023) using the storage equation. The results of an analysis demonstrated that an additional supply of up to 0.11 m3/s could be provided while maintaining the planned supply amount over a five-day period, thus ensuring a water utilization reliability of 96.3%. In addition, an additional supply of up to 0.23 m3/s was found to be feasible within the supply range stipulated in the 2023 contract for a five-day period, thus ensuring a reliability of 98.7%. However, because the reliability of water utilization is typically evaluated based on the lowest water level, our study recalculated and reassessed the potential for additional supply to ensure that the water level complied with water supply adjustment standards. The evaluation results showed that although the water utilization reliability was met, the supply availability rate generally decreased and fell below the level of concern specified in the water supply adjustment standards.