<総説>

四万十川におけるアユの産卵に適した 新たな環境場の創出に向けた取り組み

岡田 将治^＊,松岡 直明^**

Study On Extraction Of Enviromental Conditions Suitable For Spawning Eggs Of Sweet Fish And Prediction Of Its Change After Flood In The Shimanto River

Shoji OKADA^*, Naoaki MATSUOKA^**

^* * Department of Social Design Engineering, National Institute of Technology, Kochi College, 200-1, Monobe-Otsu, Nankoku, Kochi, 783-8508, JAPAN
^** Advanced Course in Civil Engineering, National Institute of Technology, Kochi College, 200-1, Monobe-Otsu, Nankoku, Kochi, 783-8508, JAPAN

Abstract

In the Shimanto River, the catch of sweet fish has been decreasing in recent years, main causes of the decrease are reduction of rapids for the spawning grounds. In this paper, we conducted detailed riverbed shape measurement before and after the flood using the UAV photogrammetry technique and survey of riverbed penetration near the spawning ground of sweet fish. Environmental conditions were extracted from the results of flow analysis during flood and the results of the search on the spawning ground, and the possibility of prediction of the formation condition of the spawning ground after the flooding was examined from the two-dimensional bed formation analysis.

Key Words: sweet fish, spawning ground, rapid and pool, penetration test of riverbed, two-dimensional bed formation analysis