Appendix B—Report of Sub-Committee on Current-Investigations of Special Committee on Flood-Waves

During the year which has elapsed since the presentation of the April, 1938, Report of the Sub-Committee on Current-Investigations on Flood-Waves, the following additional items have been noted with regard to investigations in progress in the United-States. It is not implied that this list is exhaustive. No additional data on foreign investigations have been received. (1) The Division of Research, Soil-Conservation Service, United States Department of Agriculture, in cooperation with the Horton Hydraulic Laboratory, Voorheesville, New York, has brought out a publication written by Robert E. Horton and entitled “Channel-waves subject chiefly to momentum control.” The fact that experiments on such waves were in progress in the Horton Hydraulic Laboratory was mentioned in the Report of our Sub-Committee for last year. The experiments described in the publication were performed in a wooden channel 130 feet long by 6-5/8 inches wide, with typical flow-depths of from one to six inches. The types of waves studied included the instantaneous increase, instantaneous decrease, gradual increase, gradual decrease, triangular, rectangular, and alternating. The velocities of these waves were compared with values computed by several well-known equations applicable to waves in which the effects of friction are negligible, the Koch-Carstanjen equation generally giving the best results. The publication calls attention to the desirability of making additional experiments in a much longer channel in order to study waves more comparable to typical flood-waves in rivers, where the effects of friction are more important than those of momentum.