Recovery process of aquatic insect biota was studied through two years monitoring of water quality andaquatic insects in the river Yukiya where river improvement works have been carried out by considering waterenvironment. The water environment of the river Yukiya was sound judging from the water quality indices except for thecase of high turbidity, whereas it was not good from the biota of aquatic insect. Immediately after the river improvementworks the individual number and species of aquatic insects were very small and the burrowing type of insects waspredominant and then the net-spinning type dominant. It was found that the community structure of aquatic insect couldrecover in several months if the conditions of river bed, inflow of tributary and runup of aquatic insects were arrangedwell. In addition, it was shown that the high turbidity water caused by river improvement works did not damage the biotaof aquatic insects seriously.
