The purpose of this study is to rate a group of cutthroat flumes which have the same geometric shape. Because of geometric similarity, the behavior of all flumes which are dimensionally similar to those tested should be capable of being predicted within a degree of accuracy suited for field use. Twelve flumes were used in this study, all of which have the same shape. From this study, it can be concluded that the cutthroat flume is an accurate open channel flow measuring device, which accuracy is satisfactory under both free flow and submerged flow conditions.