How does dredging work?

Over time, lined ponds, tanks, wastewater plants and chemical ponds collect sediment and debris that can cause problems if left unattended. That’s where dredging comes in, a process of removing this buildup to keep water and other contents free of problems.

But what dredging means, and more importantly, how does dredging work? Let’s break down how some of the more traditional methods of dredging work versus the latest technology for cleaner, safer and less disruptive alternatives.

What does dredging mean?

Dredging is the process of removing sediment, silt, sand and debris from the bottom or internal bodies of water or chemical tanks, ponds and other containers. Sediment naturally collects over time due to erosion, runoff and other processes. While it might seem harmless, this buildup can lead to reduced water and holding capacity, blocked flow, damaged infrastructure and even environmental concerns.

Regular maintenance, including dredging, helps restore the original depth and function of lined ponds, tanks, cooling towers, wastewater plants and other facilities. It’s a crucial step that ensures these systems continue running efficiently and safely. How dredging works depends on the type of method used.

How does dredging work? Traditional Methods Versus Robotic Innovation

These days, dredging can generally be broken down into traditional methods versus new, robotic innovations. This is how they work.

Traditional Dredging Techniques

Traditional dredging techniques are used around the world, with different applications for different purposes, including:

• Mechanical dredging involving the use of heavy machinery, such as excavators or draglines, to physically scoop sediment from the bottom. While effective, it can be disruptive, often requiring water bodies to be partially drained and operated to be stopped.
• Hydraulic dredging where suction dredgers vacuum sediment and water slurry, pumping it away to be disposed of or reused. This method is commonly used for large-scale projects like harbours or river maintenance, but requires substantial equipment and logistics.
• Cutter-suction dredging which uses a rotating cutter to loosen compact sediment while a suction pump removes the sediment or buildup. This technique is more effective for dense or hardened sediment layers.

While typically effective, traditional dredging normally involves downtime, environmental disturbance, and high labour and equipment costs. Also, lowering water levels may not always be possible or sensible, causing more problems.

Robotic Dredging Techniques

In recent years, robotic dredging has emerged as a technological advancement in sediment management. Robotic dredging uses underwater autonomous or remotely operated vehicles equipped with sediment removal tools, often with cameras or navigation systems to navigate even in low-visibility environments.

Instead of draining ponds or shutting down your industrial or mine site operations, these robots work underwater (or chemical surfaces) with precision, gently removing sediment without damaging even the most delicate liners or disturbing aquatic life. Plus, there’s no need for divers to enter the water or chemical pond or tank, so it’s a safer option with reduced downtime, less environmental impact and high efficiency.

Why You Need to Dredge

Sediment and other debris buildup may be common, but it can severely impact your operations, as well as be a safety risk. The exact benefits of dredging depends on the exact setting, but can include:

• Ensuring full volume can be reached and maintained.
• Protecting pond liners to reduce the risk of debris ripping or damaging them.
• Maintaining operational efficiency.
• Complying with environmental regulations.
• Reducing risk of shutdowns or regulation penalties.
• Ensuring smooth operation.

All of this ensures less need for repairs, maintains the safety of your water or chemical storage containers, and better running operations.

How much does dredging a Lined pond cost?

Cost is often a concern for many businesses or government departments, so how much does dredging a pond cost? The answer can vary greatly, depending on:

• Pond size and depth, with larger ponds needing more time and resources.
• Sediment type and volume, as harder or more compact sediment may require more effort.
• Access and site conditions, such as difficult locations.
• Disposal needs, including handling and transportation of dredged materials.
• Method used, with traditional dredging requiring more labour and downtime costs, and robotic dredging often helping to reduce costs.

Robotic dredging can offer cost savings by reducing downtime and environmental disruption, also providing a highly effective result.

How often is dredging required?

How often dredging is needed comes down to how quickly sediment builds up and your operational needs. Some sites may require annual dredging, while others can go several years between cleanouts.

Signs you may need dredging include:

• A noticeable reduction in water depth or volume
• Visible sediment buildup or sludge
• Changes in water flow, quality or clarity
• Operational disruptions in tanks or ponds

Monitoring and assessing for sediment can help you stay on top of your dredging needs, preventing costly damage or operational problems.