Author(s): Masashi Miyagawa; Takashi Hoshino; Yoshihiro Suenaga
Linked Author(s):
Keywords: Rtificial Reef; Numerical Calculation; Current Contro l; Hydrau lic Experiment; Sed iment
Abstract: Issue of sed iment deterioration in semi-enclosed sea for maintaining biological production process has no t been solved for many years and must be one of the most challenging themes. Various methods have been exam ined to clear this problem, sediment degradation, though, none of the effective methods improving sediment condition in the seabed withou t any help of external energy such as fossil energy source has no t developed yet. Thus we propose new method, the distinctive structure and new technology, that improves sediment condition by current control at the bottom layer b y means of ocean energy, tidal current, for increase of the disso lved oxygen concentration in the bo ttom layer water. This structure was designed as an effective generator of upwelling and downward current accelerating vertical mixture of the bo ttom water mass. In this study we examined the highly detailed 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. We hope that this vertical mixture improves sediment cond ition in the longer term by promoting increase of d issolved oxygen concentration of the bo ttom seawater. Furthermore, we monitored the fluctuation of su lfide, COD and oxidation reduction potential to grasp long term advantageous effect of the installation of the structure.
Year: 2007