Discussion: Rectangular Cutthroat Flow Measuring Flumes

The authors have presented a new design for flow measuring flumes. The flumes have a rectangular section and flat bottom, and do not have a throat section such as is provided for conventional measuring flumes. The unique feature of this design is the standard sidewall sections, which are used for all flumes ranging from 1 ft to 6 ft in throat width. In other words, the same design and length of converging and diverging sections are used for all throat widths. The authors state that "the use of a consistent geometric shape allows accurate predictions of discharge ratings for intermediate flume sizes." In addition to the rectangular flumes presented in this paper, the authors also have designed and calibrated trapezoidal cutthroat flumes, that do not have a throat section. The simplicity of the flumes is obvious and, from the information presented by the authors, it appears that they have many desirable features. The extent of field experience with the device is not given. It is assumed that the authors have had experience other than the laboratory calibrations in order to observe any particular field problems which are not apparent under laboratory conditions