Mentor Marsh Salt Fill Remediation Project

Project 357-21
Mentor Marsh Salt Fill Remediation Project
Mentor, OH

The Mentor Marsh is one of the largest natural marshes that remains along Lake Erie. In 1971, the marsh became Ohio’s first State Nature Preserve. Unfortunately, in the late 1960’s, unusable low-grade salt from a local salt mine was deposited into the original streambed of the Blackbrook Creek, a natural tributary feeding the east end of the marsh. The salt leached throughout the marsh, killing off the indigenous plant life and allowing for the non-native invasive species of Phragmites (large perennial reed grass) to take over. The Phragmites are extremely flammable when they dry, which have led to several wildfires – most notably in 1992 and 2003 where over 350 acres of the marsh land perished. Throughout the following decades, unsuccessful remediation efforts to prevent the salt leachate included: capping the salt with fly ash; rerouting the Blackbrook Creek to the north; and culverting the Blackbrook Creek.

The Mentor Marsh Salt Fill Remediation Project is one of the final efforts by the Cleveland Natural History Museum, the Ohio Environmental Protection Agency (EPA), and the Ohio Facilities Construction Commission (OFCC) to restore the marsh to its natural landscape. The remediation project removes over 165,000 tons of salt and fly ash, and repurposes 80,000 cubic yards of clean soil to recreate the natural alignment of the Blackbrook Creek.

Separating the clean material from the waste material has been a key component of this project’s success to date. The team is able to differentiate between the material types saving significant amounts of money by avoiding hauling off additional soil to the dump. Great Lakes has successfully kept this project from being a nuisance to the residents neighboring the project by communicating with them throughout the project, limiting dust on-site, and maintaining positive relationships with the neighbors.
The OFCC, administering the project on behalf of the EPA, selected the Design-Build project delivery method. The Great Lakes Construction Co.’s Design-Build team members are Osborn Engineering and HzW Environmental Consulting. The Design-Build team developed our plan over the winter of 2021/22 and began the excavation in May of this year. The project will be substantially complete at the end of October 2022 with final contract completion at the end of September 2023.