This research consists of three parts. First is the study about the flow influenced by the pile dike in the river. Second is an examination of whether regions in pile dikes are suitable as a habitat for fish. Third is a numerical analysis concerning the relationship between the flow and the behavior of fish.To complete the first part, velocity of flow and water depth in an open channel is measured. In the second part, fresh water fish (Tribolodon hakonensis) are released into the flow and their behavior is observed by video camera. Finally, the two-dimensional shallow water equation is used to examine the profile of the flow. The random walk method is adopted to examine the behavior of fish in the flow.The flow and the behavior of fish in the channel become clean through our experiment and numerical analysis.
It is necessary to be clear about the flow behavior in rivers influenced by the existence of trees and grasses on the flood plain. In this research, using a skewed compound channel with a group of trees on the flood plain, the behavior of flow in the main channel and the flood plain is studied. Authors' considerations are directed to phenomena due to the difference of arrangement of trees on the flood plain along the main channel. According to these experiments, if the arrangement of trees is changed for some reason, the flow in the skewed part changes in direction and scale. As a result, for maintenance of a river it is necessary for some notice to be taken of changes in this arrangement.Numerical analysis is used in an attempt to simulate the phenomena in the compound channel. In the analysis, the 2-D shallow water theory is adopted for simplification.
At the mouth of Nanakita River, elongated sand spit can be frequently observed due to predominance of wave motion, and is occasionally flushed during big floods. For a river planning with the presence of elongated sand spit, the unsteady flushing process of sediment at the river entrance should be considered, instead of a simple assumption of constant water level at the downstream end as has been usually employed up to now. The present paper describes influence of flood hydrograph on the time variation of river stage and corresponding development of bed topography under the actions of both tide and high flood flows at the mouth of Nanakita River during a design flood. The water level thus obtained is utilized as downstream end water level for the river planning.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.