Coordination, Innovation, and Respect for the Environment

At the heart of Duluth, Minnesota—near Lake Superior—Brennan led a large-scale environmental remediation project at Munger Landing, removing historical contamination from over 34 acres of the St. Louis River. This multi-year effort addressed legacy pollutants including PCBs, mercury, dioxins, and furans through precision hydraulic dredging, sediment dewatering, water treatment, and the strategic placement of clean sand and habitat materials.

"The scale and scope of this project demanded constant coordination, innovation, and respect for the environment," says Project Manager Casey Evenson

The Third Ward Milwaukee River remediation project is a pivotal step in cleaning up the Milwaukee River. It targets the site of a decommissioned manufactured gas plant that once operated in the area. 

A Collaborative Effort to Clean Milwaukee's River

Brennan was selected as the prime contractor for this ambitious project, tasked with dredging contaminated sediments and treating water to restore the river's health. Working closely with GEI Consultants, Inc. (GEI), the project’s design engineers, Brennan is delivering comprehensive solutions that combine environmental restoration, water treatment, and marine construction expertise.

Brennan embarked on a vital restoration project for the middle section of the Lake George Canal. The primary goal was to protect aquatic organisms by separating them from contaminated sediment through a multi-layer sediment cap.

Initial Site Challenges

Hydrographic surveys revealed areas of varying slope and stability as the first layer of cap material was placed over the canal bottom. These issues were attributed to soft underlying sediment within the canal footprint. The success of this project hinged on effective collaboration between Brennan and the U.S. Army Corps of Engineers (USACE) to address these types of challenges.

Capping is an integral part of the remediation of a water body. As the benthic community generally lives on the bottom of a lake or river, these micro-organisms are a key piece of the ecological food chain. They are also very sensitive to contaminants, and any level of exposure can greatly reduce their population. Putting a cover, or cap, of clean material such as sand, engineered materials, or stone over the bottom of the waterway can provide the clean environment in which the benthic community can flourish while trace amounts of contaminants are left to safely decompose underneath.