Abstract
A paradigm for river management was shifted after a legal reform of the river act in 1997, where preservation and mitigation of natural environment became an essential engineering issue in addition to flood control and water use. After then, multi-phase flow researches in river engineering have tremendously changed their direction from hydrodynamics to ecohydraulics that is an integrated engineering disciplines consisting of hydraulics, ecology and biochemistry. Hydraulic engineers are required to develop engineering management tools of river ecosystem that is one of most critical issues for our sustainable life in the next era. There is a wide range of hydraulic engineering disciplines that are closely related multi-phase flows found in issues from disaster mitigation to preservation of nature. In this article, hydraulic engineering researches in the last decades are briefly overviewed focusing on multi-phase flows in a river system.
