The Role of Turbulence in the Settling of Mud Flocs


  • Eric Wolanski
  • Ronald J. Gibbs
  • Yoshihiro Mazda
  • Ashish Mehta
  • Brian King


Cohesive sediments, compaction rate, fluid mud, lutocline, settling velocity, suspended mud, suspended sediment concentration, turbulence regime


The compaction rate of suspended mud depends not only on the sediment concentration but also on the turbulent intensity. This effect appears to be due to the turbulence plugging micro-channels used in the dewatering process. The compaction rate decreases by a factor of up to 10 with increasing stirring or turbulence in the inhibited settling (fluid mud) range. Our findings are based on the results of laboratory experiments where this effect was measured directly, and on observations of the suspended sediment stratification cycle at tidal frequency in the Normanby River estuary, Australia.