DREDGED FINE PARTICULATE CONTROL

2016

Engineering and Design Challenges:

• Extreme Turbidity Limitation: <29 NTUs within 30 ft and <1 NTU into Biscayne Bay

  • Extremely dispersible fine clay particles; sudden, significant high flows

• Design for ability to use, move and reuse

• Dive inspections not possible due to the presence of crocodiles.

Solutions:

• 3-Barrier System Design:

  • Diversion Barrier to blunt the flow forces and dissipate jet flow

  • Bottom-Sealed Filter Barrier, anchored on shore, to settle and filter out larger turbidity particles and to reduce and diffuse fine clay particles

  • Outermost silt curtain, off the bottom, to allow greater time for particle settlement plus diffusion

• Computational Fluid Dynamics modeled flow analysis

• Innovative self-anchoring system, removing the need for divers to enter the water

• The primary filter barrier and outer silt curtain both had reefing capabilities which allowed depth adjustments and assisted with movement of the systems from one creek site to the next without removing them from the water

Outcome:

• Water quality results in compliance throughout the project duration, both near the barriers and in adjacent Biscayne Bay

• No significant operational challenges

• The contractor was able to reef, move and redeploy using an Operations Plan