The effect of reduced flow on downstream water systems due to the Kumgangsan Dam under dry conditions

Abstract

Water resource disputes for Transboundary Rivers are frequent and critical issues among countries. The Kumgangsan Dam was constructed (in North Korea) in the Transboundary River (North Han river) that affects the water resources downstream (in South Korea) of the dam. The amount of water resource (e.g., streamflow, discharge) downstream of the Kumgangsan dam has decreased after the dam construction which might cause decreased hydroelectric power and water pollution in the downstream dams, especially during the dry season. Thus, this study analyzed the changes in the inflow into the Euiam Lake (North Han River) by the construction of the Kumgangsan Dam through hydrological modeling and examined the discharge of Chuncheon Dam (inflow into Euiam Lake) considering the flow control in the Kumgangsan Dam under the dry condition scenario. In addition, the changes of base flow during different seasons were analyzed because the majority of streamflow is contributed by the base flow during dry and drought seasons. As shown in the results, it was found that the discharge from the Kumgangsan Dam has a wide effect on the downstream dams located in South Korea. The inflow of downstream dams was significantly influenced by the discharge of the upstream dam, and the base flow was also affected by the decreased discharge of dams. Based on these findings, upstream dam managements should be carefully considered to maintain the water resource and aquatic ecosystem for the downstream dam watershed. Furthermore, the results of this study can be used as the preliminary information when discussing the problems of water allocation and flood prevention with North Korea.