Mason City 12th Street Dam

River/Stream: Winnebago River

Location: Mason City, Cerro Gordo County
        Latitude: 43.162293
        Longitude: -93.193075
        Click here to view an aerial map of the dam.

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Upstream view of dam from river right at high water.

Built: n/a

Owner: City of Mason City

Height: 3 ft.

Length: 100 ft.

Hazards: drownings, urban, portage, visibility, varying

Warning Signs:


Comments: encased sewer pipe

Approximately three blocks north of this dam is what is left of the Decker Rock Dam. That dam was built in 1865 to provide water and ice for the Decker packing plant. It was 1 foot high and 120 feet wide.

Fatalities 4

  • April 27, 2015, close call: two men in a raft, one injured, after their raft was entrapped by the dam's hydraulic
  • April 17, 2015, close call: two kayakers escaped injury after their kayaks got caught in dam undertow
  • June 27, 1996, Mike McCloskey & Rudy Heredia, went over the dam while tubing
  • July 8, 1955, Norman Pheil & Enoch Kaloplostos, swimming * **

* Pheil and Kaloplostos drowned upstream at the former dam near the "Sugar Beet" bridge on Highway 65 near the American Crystal Refining Co. plant.

** Pheil was the son of Norman Pheil Sr., whose body was found in Willow Creek east of Mason City Feb. 28, 1951. The older Pheil had been missing about a month when his body was found.

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View of dam horizon line from upstream on the east bank.