TABLE OF CONTENTS

What are Cofferdam Systems?
Types of Supplied Cofferdam Systems
Key Considerations When Choosing a Cofferdam System
Installation of Prefabricated Cofferdam Systems
Cost Considerations

Types of Supplied Cofferdam Systems

The primary types of cofferdam systems include water-filled, modular, and portable.

Water-Filled Cofferdams

These systems consist of large, flexible tubes that are filled with water to create a barrier. The water-filled design provides an adaptable and lightweight solution for controlling water in both large and small-scale projects. These systems are easy to transport, install, and remove once the job is complete.

Applications: Ideal for flood control, stream diversion, pipeline installation, and maintenance work.

Modular Cofferdam Systems

Modular systems are composed of prefabricated panels or structures that are assembled on-site. These units are engineered for easy assembly and can be reused across multiple projects. They are particularly useful for projects requiring long-term dewatering or water diversion.

Applications: Bridge repairs, dam maintenance, and long-term dewatering projects.

Portable Cofferdams

Portable cofferdams are designed to be highly mobile and are often water-inflated or air-inflated. These systems provide a portable option for quick response to flood emergencies or temporary dewatering of small work areas.

Applications: Emergency flood response, small excavation sites, and quick-fix maintenance jobs.

Key Considerations When Choosing a Cofferdam System

When selecting a prefabricated cofferdam system, there are several factors to consider to ensure the system fits your project’s needs…

Project Environment

Assess the depth, size, and flow rate of the body of water where the cofferdam will be used. Water-filled cofferdams, for instance, are well-suited for shallow or moderate-depth applications—while modular systems may be necessary for deeper waters or more complex conditions.

Material and Durability

Consider the durability of the materials used in the cofferdam system. For example, water-filled systems typically use tough, UV-resistant geotextiles—while modular systems might include steel or aluminum components. The environment, such as exposure to saltwater, may also influence material choice.

Ease of Installation and Removal

One of the major advantages of prefabricated systems is their quick installation compared to traditional built-in-place cofferdams. Most water-filled systems can be installed in just a few hours, while modular systems might take a bit longer depending on the project size. However, all prefabricated systems are designed with efficiency in mind.

Environmental Impact

Many prefabricated cofferdam systems are environmentally friendly, allowing for easier restoration of the natural environment after project completion. Water-filled systems, in particular, cause minimal disturbance to the surrounding area and can be easily drained and removed once the project is done.

Cost and Reusability

Prefabricated cofferdam systems can often be rented, which can be a more cost-effective option for short-term projects. For contractors who frequently perform dewatering tasks, purchasing a reusable system may provide better long-term value.

Installation of Prefabricated Cofferdam Systems

Installation is one of the primary advantages of using prefabricated cofferdam systems, as they are typically designed for quick and efficient deployment. Here’s a breakdown of the installation process for the different types of systems…

Water-Filled Cofferdams

Preparation: The installation area is first cleared of debris and any obstructions. Depending on the water flow and depth, the cofferdam is positioned either upstream or in the work area.

Deployment: The empty water-filled tubes are laid out in the required position. Water is then pumped from the water source (or an external water supply) into the tubes. As the tubes fill with water, they create a secure barrier that diverts or controls the flow.

Stabilization: The weight of the water provides stability. In some cases, additional anchoring is required—especially in areas with high water pressure or strong currents.

Removal: After the project is complete, the water is drained from the tubes—allowing for easy removal and reuse of the system in future projects.

Modular Cofferdams

Preparation: The installation site is prepped by leveling the area where the cofferdam will be placed. This is particularly important for ensuring the modular units connect correctly and provide a watertight barrier.

Assembly: Prefabricated panels are transported to the site and assembled. Modular systems typically use a combination of interlocking panels, braces, and other components that are bolted or connected together to form a solid barrier.

Sealing: Once assembled, the cofferdam is sealed to ensure no water leaks into the work area. Additional lining or sealing materials may be applied depending on site conditions.

Removal: Disassembling modular cofferdams is relatively simple. After the water is diverted or removed—the panels are dismantled, cleaned, and transported back for reuse.

Portable Cofferdams

Preparation: Similar to water-filled cofferdams, portable units require minimal site preparation. The area is cleared of any obstacles to ensure a smooth installation.

Deployment: The cofferdam is positioned and inflated using either water or air, depending on the system. Inflation usually takes only a few hours, making portable cofferdams ideal for emergency situations.

Stabilization: The weight and structure of the inflated cofferdam provide stabilization. In some cases, additional measures—like anchoring—may be required for added security.

Removal: Once the job is done—the cofferdam is deflated, packed up, and either stored for future use or returned to the supplier if rented.

Cost Considerations

The cost of prefabricated cofferdam systems can vary based on several factors—including the size of the system, the complexity of the project, and the duration of use. For short-term projects, renting a system may be more economical—while purchasing a modular or water-filled system may offer long-term savings for contractors frequently working in wet environments.

Leasing Options

Many suppliers offer leasing options for contractors who need cofferdams for one-time or short-duration projects. This can significantly reduce upfront costs.

Purchasing for Long-Term Use

For contractors involved in frequent marine or dewatering projects, investing in a reusable cofferdam system can provide cost savings over time—especially with systems designed for quick installation and removal.