Mississippi Lock and Dam #5A at Minnesota City, MN

(John A. Weeks III; HAER; Satellite)

USACE-mission
- Constructed 1932, placed in operation in 1936. Last major rehabilitation 1989 through 2000.
- Dam consists of a concrete structure 682 feet long with five roller gates and five tainter gates. Earth embankment 22,000 feet long.
- Concrete overflow spillway 1,000 feet long.
USACE-content
A lift of 5.5'
This site is closed to the public.

The red line highlights the earthen embankment. 

Satellite plus Paint

Roger Adank posted three photos with the comment:

WHY DID THEY SQUEEZE LOCK & DAM 5A INTO SUCH A SHORT STRETCH OF THE MISSISSIPPI?

Lock & Dam 5A wasn’t part of the original plan for the nine-foot navigation channel. It was added later, creating Pool 5A, a stretch of river only about 9.7 miles long and one of the shortest pools on the Upper Mississippi.

A 1932 Corps report explains why it was added. Winona, Minnesota, is built on a large island in the river valley. Because of that setting, engineers determined that Pool 6 could not be raised as high as originally planned without damaging the city’s sewer system and other structures and increasing the risk from high water. Adding 5A allowed engineers to keep the river level near Winona about 5½ feet lower than the original plan would have required.

That decision did more than add another lock and dam. It created a separate 9.7-mile pool through the Fountain City area, giving the Corps another place to control water levels. During dry periods, 5A helps keep the pool from dropping as much as it would under natural river conditions. Today Pool 5A includes backwaters, wildlife areas, Merrick State Park, and numerous places used for boating, fishing, paddling and wildlife watching.

A pretty remarkable piece of the Upper Mississippi shared by communities, parks and refuge lands along the Wisconsin Great River Road and Upper Mississippi River National Wildlife & Fish Refuge.

Tara Eric Corson: Winona is not on a river island. It does have 2 large man made lakes within the city but the city of Winona is in no way an island.

Roger Adank: Tara Eric Corson Good catch. I should have worded that more carefully. The National Park Service describes Winona as resting on a sandbar between the Mississippi River and Lake Winona, not literally as a river island. That setting is where the historic “Island City” description comes from. Thanks for pointing it out.

Bob Miller: Two 5s and no 23.

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The fixed spillway in the earthen dam.

Satellite

Screenshot, Flood of 2019
Bruce Larson Prairie Island Campground will be underwater for a while.
Wanda Blankenship is it ever going to go down? they are saying the river will not get back into its banks until late may. i live in cape girardeau, mo

Bruce Larson commented on his post

Sara Neave

John Weeks III

John Weeks III

John Weeks III

Update:
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In addition to providing two spare gates, the Rock Island District also loaned their Hercules 60' ringer platform barge that David Pickett caught going through L&D #18.
Two of the four photos posted by David Picket with the comment: "Corp of Engineers Rock Island district's rig @ lock and dam 18."

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David Pickett posted three photos with the comment: "Corp of Engineers crane, The Hercules. We're eliminating lock gates."
Levi Kriete  350 tons over the stern at a 70’ radius.

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HAER-grid, Part 1

HAER-grid, Part 2

The title used to say the dam was at Winona, MN, even though references put it at Minnesota City, MN, or Fountain City, MN. After discovering L&D #5, I now understand why they don't use Winona. Namely, there are two dams within a few miles of each other near Winona.

Angle Binnar shared USACE's post
We will have four temporary closure periods at Lock and Dam 5A near Fountain City, Wisconsin, from 7 a.m. to 7 p.m., July 19, 21, 26 and 28, to replace the lock chamber’s [90-year old] miter gates.
More: https://go.usa.gov/xJdJy
Sam Schropp: A really good view of the break on the outdraft.
Bob Reynolds: Sam Schropp , I thought the same thing when I looked at the picture.