Silt curtains beyond dredging and reclamation

Silt curtains were originally designed to trap sediment during dredging and reclamation works to protect the environment. Today, they are being used for a much wider range of purposes, from dewatering, outfall containment to intake protection and many other projects where sediment control is required.

We recently supplied and installed our Ecobarrier silt curtains at the Louvre Abu Dhabi project site, as a precautionary measure to contain sediment in the event a newly-flooded area required emergency dewatering. The area, located on a waterway, had been reclaimed to enable construction. Upon completion of construction works, the reclaimed area was to be excavated and then flooded. As a precaution, a bund was retained in order to contain the flooded area while the main contractor confirmed there was zero leakage into the newly constructed buildings. In the event of a leak, the pumps would need to be reactivated and the area dewatered again. The silt curtains were installed prior to flooding to contain any sediment from the dewatering process. Following approval of the integrity of the flooded location, the bund would be removed and the newly flooded site would become part of the adjacent waterway.

To describe a more unusual application for silt curtains; we also recently installed silt curtains around a glass-bottomed floating structure to reduce turbidity caused by nearby outfall pipes and dredging works, while pumping clear water into the contained area to improve visibility.  While the silt curtains prevented contaminated water from entering the contained area, the clean water pumps improved visibility underneath the glass-bottomed structure within the contained area.

Essentially, wherever sediment control is required in a marine environment, provided the correct model, layout configuration and anchoring configuration is employed, silt curtains can be an effective solution.

Selection Criteria – An Important Factor

The caveat of model selection and anchoring configuration is an important one. There are a multitude of factors that influence model and anchoring selection, from tidal forces and wave height, to water depth, location, seabed condition, layout configuration, equipment, type of construction works, type of sediment, environmental regulations and sensitivity, just to name a few.

Some people refer to silt curtains as “a necessary evil”, although I admit I have heard them called far worse. Environmental protection arguments aside, from a contractors’ perspective, they are an added headache (and cost) to deal with during construction projects – and all too often this headache is amplified by the wrong silt curtain or anchoring model being selected or incorrectly installed. This generally results in the contractor spending time and money on repairing rogue silt curtains – or worse – in site shutdowns by authorities. When you are running a large-scale dredging project at a cost in the tens of thousands of dollars per day, this is not a situation anyone wants to find themselves in.

That is why it is worth spending additional time and sometimes (but not always) additional money, to select the right model from a reputable company who backs their designs with engineering knowledge and practical experience. Speak with the experts who don’t take a one-size-fits-all or a race-to-the-bottom pricing approach; speak with the experts who truly understand the design and environmental considerations of your project and their products. Be concerned if a supplier or manufacturer asks zero questions about your application or site conditions. Manufacturing these barriers poorly is not rocket science, but doing it well is much more difficult. If you are a contractor, choose a manufacturer who encourages feedback on their products’ performance; a manufacturer who wants to make their products more effective, easier to install and less of a headache for contractors.

And don’t be afraid to ask for advice. Even if it starts with “what is a silt curtain”.

As we continue to see more ambitious construction projects, which require new and unique construction methodologies, we expect (and hope) to see more innovative uses for marine protection barriers globally. If the engineering behind the designs is understood, we can push the boundaries of their application – and hopefully see less headaches turn into migraines.

For more information on silt curtains – how they work, model comparison and selection, anchoring, installation or maintenance – please contact us at +971 4 885 3944 or email [email protected].

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