HYDRAULICS OF FLOW THROUGH A ROCKHLL DAM USING SEDIMENT-FREE WATER

ABSTRACT Rockfill dams can be used to slowly dewater sediment detention ponds. Currently, there is no suitable relationship to describe flow rate through rockfiU in terms of rockfill characteristics. This woric describes the flow of clean water through rockfill sections of different lengths, mean particle sizes, and standard deviations of particle size. Sixteen rockfill structures of varying gradations were used to define the hydraulics of turbulent flow for sediment-free water. Using the friction factor-Reynolds number relationship, five equations were developed to relate design parameters (length of rockfill, width of rockfill, flow rate, average diameter of rockfill, and standard deviation of the rockfill) to the unknown values (head loss through the rockfill, average hydraulic head within the rockfill, average velocity, friction factor, and Reynolds number). These equations were adequate for developing a stage-discharge curve and a design procedure for a rockfill structure.