早瀬の波立ちに着目した環境特性の把握

抄録

Since riffles change their environmental characteristics in every big flood, it is important to understand them in consideration of hierarchical structure of spatial scales for the maintenance or the evaluation of habitats in the riffles.

Then, we focused on wave patterns which are elements of landscape in the riffle. Waves are generated due to the physical elements which signify fluid and riverbed material properties, that is, waves will show the environmental characteristics visually. So, the objective of this paper is to show that waves are useful to understand the environmental characteristics in researching the relation between waves and these physical elements. Then, we categorize waves into 9 types by consideration of spatial scale of wave.

After some field observations and hydraulic experiments using the concept of scale, we found that the physical elements which defined wave patterns were Fr number, h/d (relative depth to gravel diameter), water surface slope, and gravel protrusion ratio (to mean riverbed surface). Finally, we showed that the physical environment in riffles was understood visually through the wave patterns which were main components of landscape in riffles.