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River flood control plays an important and essential role to prevent the loss of life and property along the riverbank. This study designed a bend flume experiment to investigate the effects of flood diversion in the middle and lower of Han River using the method of passive control. The diversion breach evolution and the relations between the diversion flow through the breach and the influencing factors were analyzed. Four stages of the entire flood diversion process of non-cohesive dikes, namely overtopping, groove formation, breach stretching and stability stages, were proposed. The research results indicated that the particle size had an obvious effect on the erosion rate during the initial flood diversion, and little influence on the maximum diversion discharge. In addition, the water head between the inside and outside of river had a significant effect on the initial flow diversion. The greater the water head, the greater the diversion discharge that occurs. Key words: middle and lower Han River, flood diversion, bend flume experiments, non-cohesive dike, diversion process. Le controle des crues joue un role important et essentiel dans la prevention de pertes de vies et de proprietes le long du rivage. La presente etude a con^u des experiences dans un canal de jaugeage courbe afin d'etudier les effets du detournement des crues dans les parties mediane et avale du fleuve Han en utilisant une technique de lutte passive. L'evolution de la breche de detournement et les relations entre le debit de detournement dans la breche et les facteurs determinants ont ete analysees. Quatre etapes ont ete proposees pour tout le processus de detournement des crues pour des digues non coherentes : le debordement, la formation de sillons, l'agrandissement de la breche et la stabilite. Les resultats de la recherche indiquent que la granulometrie avait un effet evident sur le taux d'erosion durant le detournement initial des crues, et peu d'influence sur la decharge maximale du detournement. De plus, la difference de niveau d'eau entre les parties internes et externes du fleuve avait un effet important sur le debit de detournement initial. Plus la difference de niveau d'eau etait elevee, plus le debit de detournement etait grand. [Traduit par la Redaction] Mots-cles: parties mediane et avale du fleuve Han, detournement des crues, experiences avec un canal de jaugeage courbe, digue non cohesive, processus de detournement., Introduction Flood control plays an important role in mitigating flood disasters from occurring in rivers and watersheds, particularly in inundation prevention, flood risk management, and water resource management. The diversion [...]

This paper presents a double sweep algorithm for the simultaneous solution of dynamic wave flood routing in nonlooped open channel networks. The difficulty caused by an excessive amount of computer storage required when conventionally solving nonbanded matrix equations is eliminated by using sets of recursion equations written for each specific type of channel section. The size of the coefficient matrix can be reduced from 2N X 2N to just 2N X 4, where N is the total number of computational nodes for the entire system. Consequently, execution time is also significantly shortened. The more flexible choices of spatial coordinate directions for channel branches introduced here enable the equal treatment of all channel junctions. As a result, all nonlooped channel networks can be considered as networks of the true dendritic type. This makes the proposed model applicable to a broader range of practical problems.