河床材料の鉛直構造分析を用いた浅川中流域の河床環境評価

抄録

There are many kinds of habitats for fishes inside a river channel． One of the most improtant habitats is void generated among gravels and cobbles on the riverbed． Fish can take a rest from fast flow or sometimes even ray eggs there． However， number of voids is said to be decreasing in some rivers due to several artificial impacts． In order to preserve the voids on riverbed， it is essential to find out the mechanism of how gravels form the riverbed configuration． Against such a background， we carried out field measurements． At first， we investigated the Asakawa river that is the branch of the Tamagawa riverine system which is known to be owning a lot of habitats for demersal fishes such as weatherfish or Japanese dace． We investigated how sediments compose the layer of the riverbed．