Case Study

Temporary Cofferdam Installation in Bee Spring, Kentucky

The U.S. Army Corps of Engineers (USACE) managed a major maintenance operation at Nolin River Dam in Bee Spring, Kentucky, requiring temporary dewatering of the spillway and gate structure. The objective was to create a dry, stable work zone for the inspection and repair of critical hydraulic components.

Because the spillway consisted of solid concrete, traditional methods such as steel sheet piling could not be used. The steep grade, narrow work area, and continuous water flow further eliminated the possibility of using inflatable or earthen cofferdams.

At USACE’s direction, the project contractor implemented TrapBag® Cofferdam Bags — the only practical method capable of conforming to the concrete surface while maintaining effective water control under continuous hydraulic pressure.

Project Specifications

  • Product Used: TrapBag® Cofferdam Bags
  • Installation Configurations: 2-cell units placed in a single continuous row across the spillway
  • Material: Woven polypropylene with high-strength HDPE liner
  • Fill Material: Locally sourced gravel
  • Reinforcement: Supplemental liner coverage and precise bag fitting for added wall integrity

Initial Solution

To overcome the site’s steep, confined geometry and hard concrete substrate, the contractor deployed 4-foot-tall TrapBag® Cofferdam Bags to create a temporary containment system for dewatering.

Key System Features:

  • Independent 2-Cell Units: Each unit maintained a rigid, rectangular structure that fit flush with adjacent bags for consistent wall strength and alignment.
  • Adaptability on Concrete: The flexible base conformed to the concrete surface, eliminating the need for mechanical anchoring.
  • Watertight Liner Integration: A high-strength HDPE liner was installed along the cofferdam’s face to achieve full water containment.
  • Rapid Deployment & Reusability: The modular system allowed for quick installation, removal, and future reuse on other projects.

Unintended Longevity

Although designed for temporary use, the TrapBag® Cofferdam Bags maintained structural integrity for the entire duration of the repair and remained stable under extended hydraulic exposure — demonstrating long-term durability and continued usability beyond the initial project scope.

Project Expansions and Reinforcements

Following the successful performance of the initial cofferdam structure, additional reinforcement was applied to extend the work area and maintain continuous isolation of the gate structure. The modular configuration allowed the contractor to expand the cofferdam without full reconstruction, minimizing downtime and maintaining consistent water control.

Performance

The TrapBag® Cofferdam System performed exceptionally well under continuous flow conditions. The 2-cell configuration maintained alignment and stability throughout the project, even during periods of increased discharge from Nolin River Lake.

Performance Highlights:

  • Withstood sustained hydraulic pressure without shifting or failure.
  • Maintained complete water isolation for a safe, dry work zone.
  • Enabled uninterrupted repair operations under challenging hydraulic conditions.

Key Outcomes

  1. Successful Dewatering: The cofferdam isolated the spillway, allowing for safe and efficient gate repair operations.
  2. Time Efficiency: Installation and removal took less than half the time of conventional cofferdam methods.
  3. Sustainability: The reusable TrapBag® Cofferdam Bags reduced waste, transportation needs, and overall environmental impact.

Conclusion

The Nolin River Temporary Cofferdam Project showcases how TrapBag® Cofferdam Systems deliver reliable, reusable performance in environments where conventional cofferdams cannot be installed. The system’s adaptability on concrete surfaces, rapid deployment, and proven durability make it a trusted choice for hydraulic control and maintenance projects.

For more information on this project, visit:

TrapBag® Cofferdam Systems — the smart choice for fast, reliable, and reusable water control.

Installation Highlights

  • 4-foot TrapBag® Cofferdam Bags placed directly on concrete spillway

  • Integrated HDPE liner for complete water containment

  • Installed and removed in under half the time of traditional cofferdams

  • All components reused for future projects