Project Description

Underwood Creek Flood Control & Habitat Restoration – Wisconsin

Concrete-lined flood control channels, like the one constructed on Underwood Creek in the 1960s, were designed with flood control in mind, but not public safety, aesthetics, or wildlife. Milwaukee Metropolitan Sewerage District (MMSD) worked with Inter-Fluve and the US Army Corps of Engineers (USACE) to design and construct the $11.6 million Underwood Creek project to improve all of these objectives. Initially, almost a mile of concrete-lined channel and several 2-4-foot drop structures were removed. In its place, a natural-looking and functioning channel that mimics a high-gradient mountain stream was constructed.

2019 American Council of Engineering Excellence (ACEC) Award, Best of State.

During the 1960s and 70s, Underwood Creek was altered for flood management purposes. These alterations included channel widening, construction of a trapezoidal concrete ditch, and sheet pile drop structures 2-4 feet high. This image shows the upper channel and one of the sheet pile drop structures.

This image shows the channel at normal summer flows as riparian habitat takes hold. Navigating infrastructure like the train on the left and private property on the right while meeting design goals for fish and aquatic organism passage was a challenging component of this project.

The river bed was raised so that the upper-most drop structure was no longer a hurdle for migrating aquatic species. This upper 1/3 of the project was the steepest portion of the project reach.

This image shows how water moved through the mid-channel after one of the largest rains of the 2018 summer. The water is slowed as it pushes into the floodplain.

The lower channel required sheet pile and block retaining walls to be installed to provide hydraulic capacity within the property boundaries while providing space to naturalize the stream. A two-tiered retaining wall was installed maximizes capacity, with a meandering stream and overbank flow accommodated between the lower walls. This image taken during a rain even in summer 2018 shows how the lower channel design provides more opportunity for riparian habitat and natural channel design while providing protection to private property (left) and the railroad (right)