Author(s): Tomoko Kyuka; Noriko Uchida; Ichiro Kimura; Yasuyuki Shimizu
Keywords: Vegetation invading process; Alfalfa; Morphodynamics
Abstract: The objective of this study is to observe the characteristics of seeds distribution by flow on bare sandbars, and to confirm the differences of bed morphological changes with and without vegetation on sandbars by means of laboratory experiments and numerical analysis. In the experiments, after sandbars were formed, alfalfa seeds were supplied from the inlet section of the flume. The result of experimental flume tests showed that alfalfa seeds, transported by flow, were settled at the front edge of sandbars during water discharge reduced. This is because, the flow at most downstream areas of sandbars and the front edge of sandbars de-creased earlier than that of middle area of sandbars during decreasing of discharge, as shown with the numerical results. This flow may cause the specific seeds deposition and make vegetation patches.