EFFECTS OF FLOOD PLAIN ON MAIN CHANNEL WITH FLOOD FLOW OF THE MATSUURA RIVER

In the Matsuura river digs the ground in the rice field of Azame down because there were for a long time a lot of floods, makes a flood plain there, and the natural regeneration business that starts restore the marsh is done. In this study, the flow including this Azame was analyzed by the numerical simulation. As a result of the numerical experiment, it was understood to be suppressed even to about the half when the flood plain existed while flow velocity in the narrow section reached 4.5m/s in the current state without the flood plain river channel at the flow rate peak. Moreover, the source location of the maximum flow velocity shifted to the left bank neighborhood though the peak at the flow velocity of the main current part in the flood plain downstream edge was suppressed by about 60% of the current state river channel.