HYDRAULIC JUMPS IN SEDIMENT-DRIVEN BOTTOM CURRENTS

Laboratory experiments were conducted to observe the behavior of turbidity currents in the vicinity of a slope transition. Both sediment-laden and saline hydraulic jumps were produced. The vertical structure of the currents was found to depend on flow regime. The saline and turbid hydraulic jumps showed similar characteristics. The amount of water entrained by the flows through a jump was small. The change in flow regime caused a marked reduction of the bed shear stress downstream of the jump. In nature, a turbidity current experiencing a hydraulic jump will drop most of its bedload immediately downstream from the jump, while the suspended load will respond more gradually to the change in flow regime and will deposit sediment over a distance far exceeding 1,000 times the jump height.