초록 |
In Japan, a number of various types of artificial reefs have been developed and settled to create fishery ground for the fishery production enhancement in coastal and off shore marine areas. There are many issues to be clarified about the suitable installation of artificial reefs, such as the relation between flow conditions and the biological effect of them. In this paper, a set of technologies newly developed to enhance marine resources is introduced. It consists of a hydraulic experiment and field research to select out the most appropriate shape for marine habitat restoration and a new fisheries resources enhancement structure that embodies multiple functions. The authors examined that the strong upward flow exists to the front of the panel specially designed for the generation of the upwelling water. Also, behind the structure, there are exists difference of the velocity between bottom and middle layer, besides the upward flow has been generated from the bottom layer as it was drawn into the fast current in the middle layer. Concerning the effective area of the structure, the main axis of the vortex generated by the structure has a tendency to be parallel to the direction of the mainstream, therefore it was confirmed that the effective area of vertical mixing reaches 20 times longer rearward than the structure height in length. The set of technologies was applied to coastal areas and was verified to improve biological environment in and around the fisheries resources enhancement structure. |