What’s a Silt Curtain?

Silt curtains (also known as turbidity curtains, floatation curtains and silt barriers) are used to control sediment in bodies of water. Silt curtains work by creating a physical barrier which captures sediment and silt particles, preventing dispersion into the surrounding water. This helps to minimise turbity (cloudiness) maintaining water clarity whilst protecting marine life. They are constructed using heavy duty PVC material and feature a foam block float and geotextile skirt to trap silt as water passes through.

When to Use a Silt Curtain

Silt curtains help to protect the environment and maintain compliance with regulations. Some examples of instances in which silt curtains should be used include:

• During construction – to contain sediment generated by excavation, dredging and other disturbances.
• Dredging – the excavation of material from under the water.
• Shoreline protection – to control erosion caused by waves and currents.
• Pipeline installation – deployed to minimise sediment disturbance and dispersion.

Which silt curtain for my application?

There are three different classes of silt curtains which are designed to withstand different conditions.

Class 1 Silt Curtains (Low Risk Applications)

Class 1 silt curtains are designed for calm water conditions with minimal wave action and wind. They are typically used in small lakes, ponds, and calm river areas. These curtains feature a lightweight design and are constructed with a permeable fabric that allows water to flow through while capturing sediments and preventing their dispersion. Class 1 silt curtains are often used in environmentally sensitive areas where water quality preservation is crucial.

Class 2 Silt Curtains (Medium Risk Applications)

Class 2 silt curtains are engineered to withstand moderate wave action and are commonly deployed in sheltered water bodies such as marinas, ports, and small bays. They offer improved performance compared to Class 1 curtains by incorporating additional features to withstand increased turbulence such as larger floats, additional webbing and strengthening. Class 2 silt curtains have a denser fabric and may include flotation devices to enhance stability. These curtains effectively reduce sediment dispersion, ensuring better water clarity and protecting marine ecosystems.

Class 3 Silt Curtains (High Risk Applications)

Class 3 silt curtains are the most robust type, specifically designed to handle high-energy environments with significant wave action, such as open sea areas and coastal zones. They are constructed with heavy-duty materials, including stronger fabrics, heavy duty steel chains, and larger flotation devices. Class 3 silt curtains can withstand strong currents, tidal surges, and turbulent conditions while effectively containing sediment. Their enhanced durability and strength make them ideal for large-scale construction projects and offshore activities, minimising environmental impact and preserving water quality.

One of the great things about silt curtains is their usage versatility – they can be used to encircle a construction site as well as joined for extended continuous lengths.

Why Silt Curtains are Important

Silt curtains play a key role in environmental protection and compliance. A recent example illustrates how inadequate sediment control can result in environmental impacts and penalties.

The New South Wales Environmental Protection Agency (EPA) recently issued $30,000 in penalty notices following inadequate sediment and erosion controls during roadworks at Kosciuszko National Park. This resulted in a sediment plume stretching for more than two kilometres along waterways in the national park. Events such as this can have severe and lasting impacts on plants, wildlife and the surrounding environment. Kosciuszko National Park is home to endangered species including the alpine tree frog and smoky mouse. Following this incident EPA continued to monitor construction activity to ensure appropriate controls were implemented and no further instances of pollution.

Stratex is the expert in pollution prevention controls for your worksite. Our most popular silt curtains are listed below with custom made to order versions also available. Contact us to discuss your silt curtain requirements or explore our range erosion and silt control solutions.