Photo By Melanie Peterson | Orwell Dam, near Fergus Falls, Minnesota, Sept. 16.... read more read more
The Orwell Dam is making waves with its latest improvements, including the installation of bulkheads to facilitate the replacement of its Tainter gate chains. These upgrades are designed to ensure the dam continues to operate smoothly and efficiently for years to come.
In mid-August, the pool at Orwell Dam, near Fergus Falls, Minnesota, was drawn down 14 feet over the course of 30 days to facilitate repairs and critical inspections in mid-September.
To safely complete the repairs and inspections, bulkheads were used to stop the normal flow of water through the spillway.
“Using a crane, the district’s maintenance and repair crew lifted and inserted five bulkheads weighing roughly 25,000 pounds each into slots upstream of the dam gate to block the flow and allow for schedule work to be completed,” said Billy Thomson, project manager.
While the bulkheads were in place, the two low water control pipes in the abutment walls maintained the minimum required flow of 80 cubic feet per second downstream into the Otter Tail River. After the repairs and inspections were complete and the bulkheads were removed, river levels gradually returned to normal within
three to four weeks.
Another key component of the project was the replacement of the heat shield on the dam gate, Thomson explained. The heat shield is critical for preventing ice buildup during the winter months when the dam is elevated from the water to mitigate operability issues.
The dive team also played a vital role in the project, inspecting the dam’s underwater features using a remotely operated vehicle. Once the chain replacement was complete, divers rehabilitated the floor drains in the stilling basin, a critical component for the dam’s structural stability.
“The dive team used pneumatic tools, a hammer drill, air jet, and air lift to remove compacted aggregate from 48 floor drains,” said Kraig Berberich, dive coordinator. “Divers worked at depths of 4 to 8 feet, inspecting each drain with a camera before filling it with fresh aggregate.”
Divers completed the repair work while managing water flows from 20,000 to 130,000 cubic feet per second through the low-flow control pipes, he explained.
“It’s impressive to see the various disciplines across the district coming together on site to execute the project after more than a year of planning,” Thomson said. “The maintenance and repair section; dam safety experts; divers; civil, mechanical and structural engineers; safety personnel; and Orwell Dam site staff. These inspections are essential to ensure the dam performs as designed for years to come and inform future maintenance needs.”
Orwell Dam, owned and operated by the Corps of Engineers, is a 72-year-old structure built in 1953. Standing 60 feet tall and stretching 1,344 feet at its crest, the dam plays a vital role in water supply for municipalities and agricultural needs. It also supports recreational activities such as for hunting, boating, fishing and other outdoor activities around the lake.
| Date Taken: | 12.05.2025 |
| Date Posted: | 12.05.2025 16:03 |
| Story ID: | 553193 |
| Location: | FERGUS FALLS, MINNESOTA, US |
| Web Views: | 27 |
| Downloads: | 0 |
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