This paper presents an experimental approach to observe the drift woods containing effect on the debris flow daming up performance of open type steel frame check dam structure. The hydraulic model experiments with various parameter of beam's span and drift woods containment ratio are carried out. After checking the capture mechanism of open type check dam to the debris containing the drift woods, the debris capture ratio corresponding to the drift woods containment ratio are discussed. Significant effect on the trap performance by the horizontal clearance of the check dam and the woody debris containment ratio in the debris flow are found.

Key words�Ftrap performance, grid shape check dam, woody debris, drift woods containment