流動制御構造物による海域底質環境改善技術 [in Japanese] Technology for Marine Sediment Environment Improvement by Current Control Structure [in Japanese]
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Issue of sediment deterioration in semi-enclosed sea due to eutrophication and stratification has been unsolved for a long time. The question, how to maintain biological production process by improving sediment condition, must be one of the most challenging themes for enhancement of marine resources. Various methods have been examined to clear this problem and developed such as dredging or sand covering, though, those require both huge cost for its construction and huge external energy for maintaining its function for long period in order to realize its purpose in the vast coastal area. Thus we propose this new method that improves sediment condition by current control at the bottom layer by means of ocean energy, tidal current, using our distinctive structure for increase of the dissolved oxygen concentration in the bottom layer water in the long term that realizes improvemet of sediment condition. In this study we examined the current condition around the structure by both numerical calculation and hydraulic experiment. Result of this survey apparently demonstrates that installation of the structure generates vertical mixture of the bottom seawater. Meanwhile, we monitored the fluctuation of sulfide, COD and oxidation reduction potential of the sediment around the structure to grasp the long term effect of the structure installation. Furthermore, it is known that this structure provides a massive amount of zooplankton around it and we measured the large number of aggregation of the black rock fish, <I>Sebastes inermis</I>, gathering around the structure. It is the remained task to clarify the relationship between these facts.
Eco-Engineering 20(2), 67-78, 2008-04-30
The Society of Eco-Engineering