“What these gates are, they kind of live in the water just waiting for an emergency,” said Leeanne Wimer. U.S. Army Corps of Engineers mechanical engineer, Riverdale. “We’ve never had to use them.”

Construction on Garrison Dam began in 1946 but it wasn’t until January 1956 when the dam began generating power, meaning water was allowed to flow through the intake structure to the nearby power plant and its five turbines.

“The bulkhead gates drop down in front of the penstock gates,” explained Todd Lindquist, Corps project manager, Riverdale. “They would be used to stop water if we had to do work on the regular gates. We are pulling them out and making repairs and repainting them.”

Sounds easy enough, but the gates are massive.

Kim Fundingsland/MDN Contractors are doing work on bulkhead gates on each of the five penstocks at the Garrison Dam Intake Structure. The process includes inspection and painting. The work began a year ago and is not expected to conclude until 2021.

“They are 12 feet wide by 26 feet tall and weigh 50 tons each,” said Wimer. “We’ve got 10 of them, two for each of the five penstocks.”

Contractors began working on the gates last year and won’t finish up until later in 2021. The gates were last worked on in the mid-90’s, but only repainted and little else was done. This time the gates are undergoing a complete inspection, such as a thorough examination of all welds, and making repairs as needed.

“The lifting beams at the top of the gates is being looked at and load tested. A contractor uses a machine to test to a certain tonnage,” explained Wimer.

“It’s a lot of work,” added Lindquist. “They have to be sandblasted and repainted with a vinyl paint that meets government specifications for an underwater structure.”

Contractors had to construct special stands on which to place the gates so they can be inspected and repainted. A crane is used to move the heavy gates onto the stands.

Work includes replacement of the guides on the sides of the gates. The guides fit over a slot rail built into the concrete of the intake structure that allows for the gates to be raised or lowered as necessary. As for paint, there’s an obvious color choice.

“White makes the most sense. You can see any damage easier if the gates are white,” said Wimer.

Also, said Wimer, work on the gates can continue through the winter months because all work will be done inside a heated structure. Lindquist added that contractors are also removing some asbestos from the intake structure that was part of the original construction project approximately 70 years ago.