Check dam is the most effective structural measure to protect inhabitants, properties, communities from sediment related disasters in river around mountainous and hilly areas. Check dam has a variety of functions. Among those, sediment control function is one of the most important functions of check dam. By this function, runoff sediment from upstream during large flood is saved temporarily, and this sediment is transported to downstream by medium or small floods which occur during several years or over decade after that large flood. Through this function runoff sediment is smoothed in the standpoint of time and damages by flood or sediment are reduced. The idea of this function was proposed about 70 years ago and was discussed based on qualitative recognition at first, but it had become to be discussed as a function of individual check dam quantitatively. Furthermore, the concept of this idea was gradually generalized after establishment of sediment control master plan. The process of discussions of sediment control function of check dam showed above is clarified in this paper by the review of previous papers and documents. This paper is useful for future study on sediment control effect functioned by check dam in mountain stream basins.

Key wordsFcheck dam, sediment control function, qualitative discussion, quantitative discussion