Sunday, July 25, 2021

1935 Mississippi Lock and Dam #5 at Whitman, MN

Constructed and placed in operation May 1935. Site underwent major rehabilitation from 1987 through 1998. Dam consists of concrete structure 1,619 feet long with six roller gates and 28 tainter gates. Earth embankment 18,000 feet long.
A lift of 9'

The red line highlights the earthen embankment. The yellow line shows where there is a culvert under the embankment to keep the wetlands wet.
Satellite plus Paint

Building dams in a swamp is challenging. Now that I've studied a few more dams in the upper-Upper Mississippi, I've noticed that the river channel is typically not as well defined as it is in the lower-Upper Mississippi. As shown by the red line above the dam is over three miles long because of the earth embankment. Furthermore, there is another dam, #5A, just a few miles downstream from this one with another long embankment. And it has a lift of only 5.5'.
At the time of construction of Lock and Dam Number 5T the river was about 2 to 2-1/2 miles wide, with the main channel at the foot of the bluff. The river normally maintained a width of 800 feet, widening to 2 miles in flood stages. Prior to construction, the river bottom rose gently from the river to the Wisconsin bluffs and was overgrown with brush and timber. [HAER-data]



Matthew Cooper posted four photos with the comment: "Lock & Dam 5."
I think the American Duchess is upbound and the photos are in reverse order. That is why I reversed them when I copied them. In the last photo, look at all of the speedboats that are coming into the lock to go downbound.




HAER-grid, Part 1

HAER-grid, Part 2

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