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Sedimentation Management: Reservoir and Dam Dredging

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At the most basic level, dredging is the excavation of soil and rock beneath water. The process of dredging can be divided into four phases: excavation, vertical transportation, horizontal transportation, and material disposal or use. Types of dredging projects may vary, as dredging is often done for various reasons or goals.

The process of sediment removal from a reservoir or a dam by mechanical or hydraulic means, as well as other methods, is known as dredging. As a result, it may be used to keep the storage capacity of future generations without causing significant drawdown.

At the most basic level, dredging is the excavation of soil and rock beneath water. The process of dredging can be divided into four phases: excavation, vertical transportation, horizontal transportation, and material disposal or use. Types of dredging projects may vary, as dredging is often done for various reasons or goals.

The process of sediment removal from a reservoir or a dam by mechanical or hydraulic means, as well as other methods, is known as dredging. As a result, it may be used to keep the storage capacity of future generations without causing significant drawdown.

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What is reservoir dredging?

Reservoirs have long been used to provide sufficient quantities of water to large populations. They also serve as a habitat and food source for creatures that live in the region surrounding the reservoir, such as fish and frogs. While reservoirs are an important component of modern city water management, they are not flawless.

Reservoirs today are quite well-built, but their performance can be affected by activities like deforestation, pollution, and natural erosion. All of these factors produce dirt, silt, particles, and rubbish into the reservoir. This all accumulates at the bottom of the reservoir, taking up space that water could otherwise use.

Dredging equipment can remove or reduce this deposit, which might be natural or as a consequence of human action. As a result of the reservoir's expansion, its storage capacity may be enhanced.

What is dam dredging?

Dams are an essential component of modern water management. Dams may be utilized for a variety of purposes in addition to hydroelectric generation and local agricultural needs, among them being flood control. Sedimentation can accumulate along the bottom and edge of a dam, much like at reservoirs.

The accumulation of sand, silt, and other debris to the dam's capacity for water storage. Sediments in the same way can cause harm to turbines and other components that make up the dam. Dredging is used to eliminate these risks to the dam's performance and prevent future issues.

Sedimentation Management by Means of Dredging 

Dredging is a sediment management technique that may be utilized on a wide range of water bodies, but the specific characteristics and difficulties of many reservoirs and dams necessitate particular action. As a result, reservoir and dam dredging are not the same as other types of dredging.

Some main factors that make reservoir and dam dredging unique include:

  • Reservoirs are generally found in rural areas, away from major industrial coastlines, where the bulk of dredging equipment is deployed.
  • Reservoir access may be difficult in a few situations, notably if they are surrounded by steep-walled valleys or canyon settings.
  • Reservoirs are frequently built in watershed regions that receive a lot of rain and erode naturally, resulting in sediments entering the water. Sediment is carried downstream until it piles up within the reservoir as erosion proceeds.
  • Water levels in reservoirs built in deep valleys or canyons are almost always deeper, since much of the essential infrastructure is positioned near the impounding dam.
  • Dams may accumulate sand and silt buildup at their bases and edges. This accumulation of sands, silts, and other debris limits the amount of water that can be stored in the dam.

The most important elements in determining whether dredging is the most suitable and cost-effective method include:

  • The reservoir's location
  • Volume and physical structure of the material to be removed
  • Water depth
  • Material types, and processing
  • Transportation
  • Ultimate disposal of dredged materials

Understanding the types of dredgers

Reservoir and Dam Dredging Technologies

Reservoir and dam dredging is carried out using a variety of well-known procedures and technologies.

Dredging equipment and technique are divided into two categories: mechanical and hydraulic, although there are many variations on these themes that may be used depending on the reservoir's circumstances, and its built-up sediment.

Mechanical dredging

When it comes to mechanical dredging, the most common method is to use an excavator or crane with open digging or clamshell buckets. Mechanical diggers would be installed on a flat deck barge or flexi-floats and pushed/pulled by a work boat to the required work areas where they would remove sediments and deposit them.

Mechanical dredging may also be carried out by excavators working on land near the coast. In certain circumstances, water levels might be lowered for a short time. Mechanical excavators may move straight onto the lake bed (in some cases, necessitating pressure reduction methods to prevent sinking into soft material).

Benefits of mechanical dredging

  • Can dig through harder materials, such as cobblestone or other masonry, with a clamshell bucket, excavator, standard-size backhoe, and the like.
  • They can dig and grade to a high degree of accuracy.
  • Sediment volumes on land are reduced, making management and storage easier.
  • Removes significant amounts of sediments at or near the in-situ state present at the bottom of reservoirs.

Hydraulic dredging

Hydraulic dredging is the transport of sediments in a slurry form through temporary pipelines from the site of extraction to a designated repository area using dredging pumps.

If the pipeline transportation distance and/or extra elevation difference lowers the discharge slurry velocity of the dredge pump below acceptable levels, boosters may be necessary to fill up the material.

Benefits of hydraulic dredging

  • Avoiding the need for “double handling” of material onto land by pumping directly from the point of dredging to the point of stockpiling or disposal.
  • More efficient production rates are typically obtained by properly selecting equipment, piping, and pumps than through mechanical dredging.

Do you have a dam that requires dredging?

U.S Aqua is the leading provider of dam dredging services in the United States, and we’re ready to help your dam get back on track.

If your dam is still functional but just needs some maintenance, then let us take care of it for you. We can clean out sediment buildup or clear away any debris that may be clogging up your water flow without disrupting your operations at all.

No matter what kind of project you require done, give us a call today and see how quickly we can get started on it for you!

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References

Reservoir Dredging: A Practical Overview - https://www.westerndredging.org/phocadownload/Workgroups/Reservoir_Dredging/WEDA%20Technical%20Report%20-%20Practical%20Guide%20to%20Reservoir%20Dredging.pdf


About U.S. Aqua Services

U.S. Aqua Services was created to support the dredging process in advancing commerce and responding to its many challenges. To accomplish this, our dredging company assembled an exceptional group of experienced individuals and a diverse inventory of dredge equipment and excavator dredge pumps.

We offer dredging equipment rental services so you can have access to the latest and greatest in dredging technology without having to pay to maintain it, transport, and store it, along with dewatering services.

With an emphasis on mobility, dependability, durability, diversity, efficiency, and safety, our dredging rental company can ensure that our different types of dredging systems are easy to move through any terrain and can work in the most rugged and remote environments. Our multi-function hydraulic systems are built with jetting and mechanical options that can efficiently move loose sediment or stiff layers of clay.

US Aqua services also and maintains a ready fleet of Amphibious Marsh Equipment capable of completing projects in some of the harshest and most remote environments. U.S Aqua is also the dealer for Louisiana of the amphibious vehicle Fat Truck. No matter the size or scope of the job or the remoteness of your work location, you can rely on Fat Truck’s industrial off-road utility vehicles to get the job done right.