Coon Rapids Dam
Mississippi River Dam
Coon Rapids, MN

Coon Rapids Dam

• Structure: Coon Rapids Dam.
• Location: River Mile 866.2.
• Dam Width: 2,150 Feet Overall, 1,000 Foot Longest Structure.
• River Elevation (Pool): 823 Feet.
• River Elevation (Outflow): 810 Feet.
• Water Fall: 13 Feet.
• Date Opened: Built 1913, Rebuilt 1997.
Original dam was built in 1913 was made of earth and concrete resting on wood and steel piles. Demand for hydro power dropped in the 1960s, and the dam was abandoned December 31, 1966. Structure was taken over by the county park districts to be used as a regional recreation area. The dam itself and the overhead pedestrian bridge was removed and rebuilt in 1995 to 1997. While the old dam had 33 gates, the new dam has 10 gates, but they are much larger. Five of the gates are crest gates, which means that water flows over the gate, and the gate lifts up to stop the flow of water. Four of these crest gates are inflatable rubber bladders. The Coon Rapids Dam is the largest dam in the world that uses these rubber gates.

The Coon Rapids dam does not have a lock system for navigation traffic. That means that this is the true head of navigation for the great river. All dams south of this point have locks and are primarily for navigation, with the Keokuk Power Dam being the notable exception. The Coon Rapids dam is primary for recreation to maintain a constant pool depth. Dams north of here were installed for a variety of reasons from flood control and reservoir management to hydro power and logging.

The photo above is looking east across the main river channel structure. The photo was taken during a period of high water. The noise and power of the water flowing through this dam is nothing short of amazing. The photo below is looking east towards the walkway that runs across the top of the main dam structure. This walkway is open to the public and is heavily used by pedestrians, bikers, and rollerbladers.


Coon Rapids Dam
Coon Rapids Dam
The photo above shows some of the fishing platforms on the west side of the dam. The photo below shows the first gate of the dam, and the walkway above the dam structure.

Coon Rapids Dam
Coon Rapids Dam
The photo above shows a sign that explains how the inflatable dam gates function. The dam features five inflatable gates. The photo below is looking up river on a cold windy spring afternoon.

Coon Rapids Dam
Coon Rapids Dam
The photo above is looking towards the east across the main dam. This view is from during the spring runoff, which means a high volume of water flowing through the dam. The photo below is the dam on the east channel of the river. This channel once fed the power house and contains the overflow channel.

Coon Rapids Dam
Coon Rapids Dam
These two photos show the lower of two bridges over the dam overflow gates.

Coon Rapids Dam
Coon Rapids Dam
The photo above is a view of the east channel dam taken from the upper overflow channel bridge. The photo below is another photo of the lower bridge across the overflow outlet.

Coon Rapids Dam
Coon Rapids Dam
The photo above is a view of the overflow channel. Prior to the rebuild, this outlet contained a roller gate that could be adjusted hydraulically. Today, that gate is part of a history exhibit. The overflow is now a fixed concrete gate that allows water to flow over the spillway once it reaches a certain level. The photo below shows the fishing deck on the east channel dam structure.

Coon Rapids Dam
Coon Rapids Dam
The photo above shows an earth fill section of the dam on the far east end of the structure. The building in the background is the Anoka County dam visitors center. Note that there is also a visitors center on the Hennepin County side of the dam. The photo below is a historical marker placed at the dam site.

Coon Rapids Dam

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Photo and text by John A. Weeks III, Copyright © 2005, all rights reserved.
For further information, contact: john@johnweeks.com