Abstract
The purposes of this study are to examine clearly the hydraulics functions of groins and the characteristic of fish behavior around the groins. To complete them, the hydraulics experiments and to observe the movements of fish were done.
As the results, 1) curved flow was formed by the groin, 2) low velocity areas were formed in the downstream of the groin and 3) The relativity of the riverbed scour, gravel deposit, and vorticity is low. Moreover, fish stayed in the low velocity areas and big vorticity areas. On the other hand, fish run up in the high velocity and small vorticity areas. Therefore, fish behavior depends on the vorticity.
In Addition, numerical analyses were done. As the results, the formation situation of a curved flow and vorticity reproduced roughly. However, scare of velocity or vorticity were not able to reproduce.
