AERATION PERFORMANCE OF LABYRINTH WEIRS OF BOULDERS

摘要

A set of aeration performance experiments was conducted in order to verify aeration efficiency for the linear weir, ogee-spillway type weir, and labyrinth weir. It was found from the experiments that the oxygen transfer efficiency at the labyrinth weir was the highest, while the efficiency at the ogee-spillway type weir was the lowest among the three types tested in this study. It was also revealed that the aeration efficiency of the labyrinth weir increases as the included angles become smaller. Based on the results of the experimental study, a prototype labyrinth weir made of crib with boulders was constructed and tested at a stream site. The averaged value for the oxygen transfer efficiency observed at the prototype weir was 0.18, that is lower than the values obtained from the lab experiment. It is expected that the results from this study would serve for the improvement of design of weirs with high aeration efficiency.