남ㆍ북한 공유하천의 관리 현황과 물안보 확보 방향

Abstract

Abstract Developing a Water Security Framework of Transboundary Rivers between South and North Korea The Bukhan and Imjin River are transboundary (i.e. shared) rivers which originate in North Korea and flow into South Korea. Because both rivers flow through the demilitarized zone (DMZ), they enjoy comparatively better environmental and ecological conditions than other rivers due to the minimal human presence in the DMZ. However, since dams have been constructed in North Korean territory (upstream) of the rivers, flow output and fisheries productivity has been decreasing. In spite of the necessity for cooperative management of the rivers, the division of the Korean peninsula has restricted cooperative actions between the two nations. In this study, Inter-Korean shared rivers were investigated from the viewpoint of "water security." Water security is a complex concept in the management, conservation and utilization of freshwater resources. The concept is useful in analyzing the diverse characteristics of transboundary rivers and to investigate their vulnerability to climate change. This study was thus aimed at developing basic principles toward devising a common water security framework between the two Koreas. We investigated both the conflicts and cooperation that have occurred between the two Koreas with respect to the Bukhan and Imjin River. At the Imjin River, fisherman have suffered from sudden discharges by North Korean dams without notification. After North Korea constructed the Im-nam Dam in the upper reaches of the Bukhan River, the downstream flow was reduced. This also led to difficulty in the operation of hydroelectric dams and the maintenance of water supplies. Although dialogue on flood prevention from the Imjin River took place several times after the Inter-Korean Summit in 2000, discussion on substantial measures was minimal. In the case of the Bukhan River, South Korea requested that North Korea provide notification of the discharge plans for the Im-nam Dam in advance. North Korea accepted the request and South Korea could take preventative action. Still, fundamental problems such as notification on discharges or flow management have still not been resolved, and only basic studies on the rivers were carried out. We focused on the Imjin River and analyzed the change of river flow, water quality and land coverage of the river. We compared the river flow of the upper and lower reaches of the Imjin River and the tributary Hantan River. Although the available data were limited, it seems that the contribution of the flow from North Korea to the lower reaches increased from October to December 2007. In other words, the flow from North Korea has increased since 2004. It is likely that the hydroelectric dams of North Korea in the upper reaches of the river were discharged to generate electricity prior to the construction of the Hwang-gang dam. The water quality of the upper reaches of the Imjin River was Grade I(a) to I(b) in terms of BOD, COD and T-P. However, tributaries showed poor water quality. The water quality of the tributary, Sincheon, was Grade VI in terms of COD and T-P. Despite the poor water quality of the tributaries, the large water quantity and high water quality of the mainstream has resulted in good water quality for the lower reaches of the Imjin. The BOD and COD of the downstream was I(a) to I(b) and I(b) to II, respectively. Therefore, it is likely that a change in the flow of the mainstream of the Imjin River may affect the environmental and ecological status of the lower reaches significantly. The change of land coverage in the Imjin River basin was analyzed between 1980 and 1990. More changes of land cover were observed near the DMZ. The land cover of the upper reaches showed more changes than that of the lower reaches. When the coverage of forest decreases and that of grassland increases, rainfall produces more sediment and it may degrade river water quality. The reduction of wetland areas in South Korea may cause negative impact on the aquatic ecosystem. The factors of water insecurity at the Imjin River were determined as follows - sudden discharge from North Korean dams, flood risk, long-term water shortage by the upstream dams, the development of North Korean regions in the future, and non-cooperative practices among South Korean institutions. In order to establish common water security in the Imjin River, there is no choice but to manage the river in cooperation between the two Koreas, treating the Imjin River as a transboundary resource. To minimize the risk of floods and droughts in the Imjin River basin in the future, a kind of 'Imjin River Management Committee' can be established and the water infrastructure, including dams can be managed by agreement between two countries. In the progress of negotiations between North and South Korea, "side payments" can be considered to reduce damages from floods and droughts. Once the river is polluted, restoration of the river will require substantially more time, effort, and expenditure, making negotiation more difficult. Accordingly, support for environmental infrastructure in North Korea can be studied as a preventative measure.