Silt can carry pollutants, cloud waters an cover bottom life. How do you prevent or mitigate the problem?
The video above from Western Washington University shows how silt-contaminated currents move rapidly throug water bodies. The video shows how widely silt pollution will affect the waters, and illustrate how important it is to manage this when working by or in water bodies.
Construction activities, dredging, filling – they all produce silt that spread in the water bodies. Very often the silt particles carry pollutants and nutrients that affect the water environment negatively. The nutrients may cause algae bloomings, the pollutants may get into the marine life and accumulate in the food chain.
The prevention or mitigation of the silt distribution in the water bodies are important, and there are measures that can help.
A Bubble curtain will create a vertical current; “plume”. The vertical current will catch and divert the weaker currents carrying the silt particles. There will be sedimentation of the particles inside the bubble curtain. The curtain is not completely unpermeable, but correctly constructed it will substantially mitigate the silt pollution. Boats can sail across the curtain, and the bubble curtain are not damaged by propeller currents and other currents since there are only free air bubbles and not technical installation above the the seabed.
Silt curtains are basically a textile “wall” that separate the affected water from the water you want to protect. The textile has an integrated floater, normally a rigid or inflated pipe/hose, and a sinker like a steel chain or lead rope.
The silt curtains are efficient, but they are very difficult to open or cross by boat traffic. A silt curtain has a large area in water, affected by currents and tides, and are not suitable for installations in waters like rivers, tidal zones and generally places with currents.
Waens work with both the above types of silt pollution prevention. We can advice on the best measures depending on type of site, permit limitations, water conditions and duration of the works.