Mon-Maq Dam


River/Stream: Maquoketa River

Location: Monticello, Jones County
        Latitude: 42.244765
        Longitude: -91.172125
        Click here to view an aerial map of the dam.

View of dam from below on river left

Built: 1910

Owner: Jones County Conservation Board

Height: 9.5 ft.

Length: 441 ft.

Hazards: usage, visibility

Warning Signs: good

Portage: Portage on river-left (east bank.)

Comments: 2008 flooding severely weakened and undermined the dam. Jones County Conservation is exploring options to modify the dam and water trail. Three options for replacing the dam with structures designed to enhance the river's natural and recreational attributes are under consideration.

Alternative A, the most expensive at an estimated cost of $2.8 million, entails four stone structures resembling mini-waterfalls. The largest, with a 3-foot drop, would be built at the dam site. Three smaller ones, each with a 1 1/2-foot drop, would be constructed in a 2-mile stretch of river upstream of the dam.

Alternative B (estimated cost: $1.8 million) would consist of the stone structure with the 3-foot drop at the dam site.

Alternative C (estimated cost: $2.3 million) entails replacement of the dam with a rock arch rapids consisting of from six to seven drops, each in the 12- to 18-inch range.


Warning sign with portage marker