Box Dam Water Intrusion Repair

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We were engaged by another contractor to provide geotechnical support to a state highway department in constructing foam walls on both flanks of a box dam. The objective was to mitigate water intrusion at the interface between the box dam and the select fill material used for the roadway embankment. The structure was situated directly on the Wisconsin River and was among the few box dams in the region required to operate to manage seasonal flooding of adjacent cranberry bogs.

Initial construction of the foam walls was completed successfully. However, upon removal of the sheet piling by the highway department, water began to infiltrate along the dam joints and beneath the dam almost immediately. This led to significant soil piping and flushing, creating a high risk of roadway embankment erosion and potential failure. With the cranberry harvest imminent, full reconstruction of the dam was not feasible due to both time constraints and the substantial cost involved.

In response, we developed a strategy to seal the dam from the interior. The plan included targeted void filling, application of waterproofing measures, and structural stabilization to ensure the dam’s continued operational performance and the long-term preservation of the dam & roadway.

The highway department faced a situation with extremely limited options. Full reconstruction of the box dam or extensive repair from the outside was not feasible within the available schedule, particularly with the cranberry harvest imminent. Time constraints and the high cost of conventional methods eliminated alternative solutions.

Our team was the only viable option to address the issue effectively. There was no margin for error—failure to stabilize the dam could result in significant soil erosion, roadway compromise, and disruption of cranberry bog operations, with potential costs reaching well into the millions of dollars. The problem demanded an immediate, reliable solution, and we were tasked with delivering a repair that would restore structural integrity, prevent further water intrusion, and ensure the dam and roadway remained operational through the critical harvest period and beyond.

To address the water intrusion and structural concerns, our team implemented a targeted foam injection strategy using 2.5 tons of HF402 HydroFoam. HF402 was selected specifically for this repair due to the large body of water and persistently wet conditions at the site. HydroFoam is engineered to resist hydrolysis—the chemical breakdown of materials in water—and is capable of setting and maintaining dimensional stability in fully saturated conditions, making it the optimal solution for sealing the dam joints and voids.

The repair process included deep foam injection at the end of the box dam to prevent water intrusion beneath the structure. We installed 16 injection sites per joint of the dam, which allowed the expanding foam to displace failed butyl and completely fill all voids within the joints. After the deep injection, we performed open-spray applications along all dam joints to ensure that every area was fully sealed. In addition, the exposed sheet piling and remaining seams were sprayed with HydroFoam to guarantee zero water infiltration.

Following completion of the process and removal of the main sheet piling, the dam was thoroughly tested and demonstrated zero water intrusion, effectively mitigating the risk of millions of dollars in potential damage to the roadway and surrounding cranberry bog operations. The total cost for the project was approximately $80,000, representing a fraction of the potential loss while providing a permanent, durable solution.

Throughout the project, we collaborated closely with local engineers and commissioners to meet all operational and regulatory requirements. It was a privilege to deliver a solution that not only stabilized the structure but also ensured continuity of critical local infrastructure and agricultural operations.