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The reasons why levee breaches during floods are largely due to overtopping, seepage, and structurally induced piping. According to an analysis of domestic and overseas reported cases of levee breaches, overtopping was found to be the cause for approximately 40% of all cases of breach. Despite such efforts of previous research to establish disaster prevention plans associated with levee breaches, to enhance our understanding of the processes and reasons, further research regarding the prediction of levee breaches must be undertaken by accumulating test data under several different conditions and further verification of the data using numerical models must also be undertaken. In this study, development of technologies regarding a new environmentally friendly bio-polymer capable of protecting levees from erosion is being undertaken. Breach mechanisms was assessed using an image measurement system that collected data regarding the breach progress of the levee, close-up views of the breaching surface, and the formation of the final breaching cross-sections. Further, levee slopes were covered with a bio-soil mixed with a new substance for the purpose of analyzing the stability and the time delay effect.

Vegetation is one of the key factors in river management where environmental aspects as well as flood protection should be taken into consideration. Because of this, numerous studies have been done including experiments and hydrodynamic modelling. Because most of experimental studies were made in indoor laboratory flumes with artificial trees, there are still limitations in transfer of their result to actual channels. REC (River Experiment Center) of Korea has been operating three real-scale, nature-like outdoor experimental channels. In a straight channel, several 4x2 m actual willow patches were planted and have been grown last three years for studies on flow vegetation interaction. A set of intensive flow measurement was made around the first upstream willow patch using ADVs together with measurement of vegetation properties. The experiments were made under several different depth conditions simulating snow-melt and flash-flood. Distribution of flow around and through the patch was characterized along with vertical profiles. The results of the experiment enhance understanding on interaction of flow and actual vegetation in a natural channel and may also provide information on flow resistance used for hydrodynamic modelling and validation.