A formerly contaminated water system has evolved into a safe and serene setting where local Bangor community residents now recreate, wildlife and plant life flourishes, and nature enthusiasts and students study a revitalized river ecosystem.   This transformation is due in part to: 1) an innovative treatment to remove 27,445 tons of contaminated sediment and debris, 2) a cooperative coordinating effort between the city and the DEQ, and 3) a combination of state funding and settlement monies from liable parties to address the contamination.  Future plans include boardwalks, nature trails and fishing platforms by this Van Buren County river community.

Bangor Sediment Remediation Project

The CR 681 Black River site, also known as the Bangor Mill Pond, is a state funded sediment remediation project implemented by DEQ Remediation and Redevelopment Division staff with the Kalamazoo District office.  The site is a formerly impounded portion of the Black River, located within the City of Bangor in Van Buren County. 

Sediment Sampling

Following several rounds of sampling, sediments contaminated with polychlorinated biphenyls (PCBs) and chromium were identified in the Black River and surrounding marshland (former Mill Pond) near the outfall of the former Du-Wel plant, and downstream as far as the dam at Second Street.  The plant historically was a metal plating, die casting and painting facility.

The site was recommended for state funding because of the effect of PCBs and the direct contact hazard for heavy metals in the sediments. 

 Sediment Removal

The most cost effective remedy was to remove the contaminated sediments and dispose of them offsite.  The remedy involved mechanical excavation, along with an innovative combination of hydraulic dredging using geobags for sediment dewatering.   The geobags used at this project were large porous geofabric bags measuring 220 feet long and 7 feet in diameter placed in an impermeable containment area located just off shore.  Contaminated sediment was pumped directly from the hydraulic dredge into the geobags through 600 feet of flexible pipe.   Waste water drained from the geobags was filtered, treated with two types of activated carbon, tested and returned to the river.  The geobags were opened and the dry sediment material transported to a licensed landfill.  This innovative treatment process is also being implemented at other DEQ projects in Monroe and Oakland counties (click on county name to view project).

   Mechanical excavation                    Hydraulic dredging                          Geobags: sediment dewatering

 Following sediment removal, additional sampling was completed to confirm that cleanup levels had been achieved.  In all, 27,445 tons of contaminated sediments and tree stumps were removed.   A cooperative effort between the city and DEQ also resulted in stream bank erosion control measures to prevent scouring and erosion around existing river bridge supports.

Waste water treatment

 Engineering Controls

• Sediment controls using in-stream turbidity curtains

•  Water clarity monitoring at least 4 times per day

•  Water quality monitoring

•  Erosion and runoff control

•  Stream diversions

• Temporary sheet pile dam (to raise the water level in one area of the project)

•  Dust suppression

•  Equipment decontamination

•  Perimeter security fencing

•  Stream bank restoration

                                                                 Stream turbidity curtains

Work completed

The Bangor sediment remediation project now provides for unrestricted recreational use of the area and the city plans to build boardwalks, nature trails, and fishing platforms.  The total cost of the project was nearly $4.4 million, with approximately $1 million received in a settlement with the former operator of the Du-Wel facility.  The DEQ Level of Effort consultant for the project was MACTEC Engineering and Consulting, and the Trade Contractor was Homrich, Inc.   An environmental excellence award by the Michigan Association of Environmental Professionals was recently awarded to MACTEC for this project.

Final stream bank restoration

incorporating rip rap for erosion control

Additional Information

Two recently published articles on this cleanup effort, written by Bangor City Manager Larry Nielsen, include: 

• Restoring the Connections, Stories of Ecosystem Restoration in the Great Lakes, Tip of the Mitt Watershed Council, 2004; scroll down to story on page 12, entitled:  Polishing a Jewel – Sediment Removal Restores Bangor’s Natural Assets, at this web address:  www.greatlakesrestoration.net/examples.html. 
• Perseverance pays off to clean Bangor’s Mill Pond, in Michigan Municipal Review, July/August 2004. 

The project files for the Bangor sediment remediation project are available through DEQ Project Manager Carol Hefferan, DEQ Remediation and Redevelopment Division, Kalamazoo District Office, 7953 Adobe Road, Kalamazoo; or by calling:  269-567-3500.