수질보전을 위한 새만금호 배수갑문 운영 대안에 관한 연구

Abstract

Operation of Gate for Conservation of Water Quality at Saemangeum Region Recently, development projects in the Saemangeum region have been revised to provide more intensive economic development while preserving ecological value. According to the new plan by the Office of the Prime Minister, Saemangeum will be developed as an international water city modeled after Venice or Amsterdam. As a consequence water quality in Saemangeum is growing more important. The development project now requires comprehensive water quality improvement plans not only for agricultural water (water quality level 4) but also for tourism and leisure (water quality level 3). If this is the case, the amount of water interaction between Lake Saemangeum and the outer sea is the most influential factor for water quality in this project. In this study, a simple gate operation model was developed and used to simulate the amount of water discharge interaction and the water level of Lake Saemangeum. The first simulation changes the water management level of Lake Saemangeum from EL.(-)1.5m to EL.(+)1.0m. The results indicated that the amount of water interaction decreased to 19% compared to the current water management level. The second simulation fixes the water management level of the lake and uses some of the gates while other gates remain permanently open. This did not affect water interaction as much as varying water management levels. In the third simulation gates were operated for 100 year flood events with and without ecological land development in the northern part of the Saemangeum region. The simulation results indicate that the flood water level can be raised up to EL.(-)0.27m with water management levels of EL.(-)1.5m. When ecological land development occurs with the lake dyke, the flood water level is 0.14m higher at a value of EL.(-)0.13m. When all the development plans are achieved, the response time to the flood wave was much faster than the current situation due to the decrease in volume of Lake Saemangeum. In addition to this, the management water level was set for EL.(-)1.5m decreasing the amount of water interaction to cause water quality problems. The best alternative for operating the gates to manage water quality in Lake Saemangeum would be an increase in the amount of water interaction. Therefore the management water level should not be considered as a strict guideline and should be managed more flexibly to increase the amount of water interaction.