Mayville Dam Reconstruction & River Restoration
Rebuilding Critical Infrastructure Along the Goose River
When historic flooding damaged Mayville Dam #2 in 2022, the City of Mayville faced more than just repairing a damaged structure. The flood had severely eroded the riverbank, exposed existing infrastructure, and left behind a low-head dam that no longer met the community’s long-term safety and environmental needs.
Comstock Construction partnered with Moore Engineering and the City of Mayville to reconstruct the site using a modern river restoration approach. Rather than simply replacing the original dam, the project transformed this section of the Goose River into a safer, more resilient waterway through engineered earthwork, erosion control, and rock riffle construction.
Today, the completed project not only protects the river corridor from future flooding and erosion but also improves recreation, fish habitat, and public safety for generations to come.
Why the Project Was Needed
Spring flooding caused extensive damage to the existing dam and surrounding riverbanks, washing out portions of the embankment and compromising the aging structure. Repairing the original low-head dam wasn’t the best long-term solution.
Instead, project partners chose to reconstruct the river using a design that works with the natural flow of the water. This approach improves flood resilience, reduces future maintenance needs, restores fish passage, and eliminates the dangerous hydraulic conditions often associated with traditional low-head dams.
The result is a safer, more sustainable piece of infrastructure that better serves both the community and the surrounding environment.
Heavy Civil Construction & Earthwork Scope
As the civil contractor on the project, Comstock Construction completed a wide range of earthwork, excavation, and river restoration activities to reconstruct and stabilize this section of the Goose River. Our scope of work included:
- Demolition of the existing dam structure
- Removal of damaged sheet piling
- Salvaging existing rock for reuse where possible
- River channel excavation and grading
- Repair of flood washouts and eroded riverbanks
- Embankment reconstruction and stabilization
- Installation of approximately 13,000 cubic yards of riprap
- Placement of nearly 1,000 engineered boulders
- Construction of the new engineered rock riffle system
- Final grading and site restoration
This type of heavy civil construction requires careful coordination between earthmoving operations, hydraulic design, environmental considerations, and precise rock placement to ensure the river performs as intended for years to come.
What Are Rock Riffles?
One of the defining features of the project is its engineered rock riffle system. Unlike traditional dams that create a single vertical drop, rock riffles use strategically placed boulders and riprap to gradually step water through the channel while maintaining a more natural river profile.
The design helps slow water velocities, reduce erosion, improve water quality through natural aeration, and allow fish to move freely upstream. It also eliminates the dangerous recirculating currents commonly found below low-head dams, creating a much safer environment for anglers, paddlers, and other recreational users.
Learn more about Safer Dam Alternatives on our blog post here.
Built for the Future
The completed Mayville Dam Reconstruction project provides lasting benefits that extend far beyond replacing aging infrastructure.
By combining excavation, grading, erosion control, and river restoration techniques, the project protects the surrounding landscape from future flood damage while improving the health of the Goose River ecosystem. Community members can once again enjoy safer fishing, boating, and outdoor recreation, while the City benefits from a more resilient piece of infrastructure designed to withstand future high-water events.
Projects like this demonstrate how thoughtful civil construction can solve complex infrastructure challenges while creating lasting value for the communities we serve.
See more of our Civil Projects here.