| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve water-quality environment, and to easily make fishes go up because a dam and a weir aiming at water utilization are installed in a river basin, movement in an upstream and a downstream of fishes is limited remarkably, fishes and shellfishes ingesting nutriments in water are decreased, nutrition is accumulated in water, water is contaminated and taste as food as well as fishery environment are lower remarkably. SOLUTION: Movable weirs 2 and 3 are arranged left and right respectively at both ends of the upstream and the downstream in a contact oxidation levee 1 with a large number of voids continuously formed in the longitudinal direction of flowing water in a river and a water way, fishes are made to go up easily by alternately operating the movable weirs 2 and 3 in the upstream and the downstream, and water in the river is permeated and purified in the contact oxidation levee 1 while the clogging of the levee 1 is prevented and a water- quality purification effect is continued by alternately operating the movable weirs 2 and 3 to the left and the right.</p> |
