Investigation of Hydraulic Flow Characteristics on Drop Structures

Drop structures are required if the slope of the ground level is steeper than the maximum allowable gradient channel. Drop structures become bigger as height increases. Its hydraulic capability may be reduced due to variations of jets falling on the stilling basin floor due to discharge changing. Drop structures should not be used if the change in energy level exceeds 1.50 m. The free-falling overflow on drop structures will hit the stilling basin and move downstream. As a result of overflows and turbulence in the pool below the nappe, some energy is dissipated at the front. The rest of the energy will be reduced downstream. The objectives of this study are to investigate the hydraulics flow behavior in straight and sloping drop structures and to investigate hydraulics flow behavior in a single and serial vertical drop (stepped drop). The hydraulic model results of single and stepped drop structures are compared to obtain flow behavior and energy dissipation information. The comparisons are specific to the flow parameters, including flow depth at the drop structures toe, flow depth after the jump, and hydraulic jump length.