Union Street Dam Monitoring

October 27, 2023 Update

The DPS Parks and Recreation Division will be performing tree maintenance activities at the Union Street Dam. The work will be taking place on the north and south sides of the Boardman River. The work will begin on October 27, 2023 at 7:30 am and will continue with appropriate signage until complete. 

The trail over the dam between parking lot J (south side of river) and the alley on the north will be closed to all bicycle and pedestrian traffic during the work with Cass and Union Street will serving as the detour. Access to the river and boardwalk will remain in place from the Union Street Bridge and Lot J. Appropriate signage will be in place.  Please use alternate routes avoiding this area to reduce congestion, delay, and promote worker safety. 

The maintenance is being performed in accordance with the State of Michigan EGLE Dam Safety Inspection Report for Dam ID No. 511. In 2021, a required MDEQ Dam Safety Unit inspection was performed and indicated a downgraded rating from Good to Fair/Poor condition. The Michigan Dam Safety recommended several maintenance activities and investigatory tasks in the inspection report which included tree maintenance. In November 2021, the City began contracting for dam monitoring services. The location of tree maintenance at the Union Street Dam is at the future site of the FishPass project. A start date for FishPass construction has not been determined at this time.

The City has contracted for monitoring services of the Union Street Dam due to an MDEQ downgrade of dam condition. A required MDEQ Dam Safety Unit inspection was recently performed and indicated a downgraded rating from Good to Fair/Poor condition. The Michigan Dam Safety Unit inspected the Union Street Dam on May 27, 2021, and recommended several maintenance activities and investigatory tasks in their June 18, 2021 inspection report.

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Background

The City of Traverse City has been permitted through a Joint Permit Application process with the USACOE and MDEQ for the replacement of the Union Street Dam. Due to unexpected delays, because of the litigation against the City in connection with the FishPass Project, the City has contracted with AECOM to perform monitoring services at the Union Street Dam that began in November 2022. The scope of work is as follows;

• Establishing a topographic survey and survey monuments on the dam
• Investigating slope stability and seepage and monitoring piezometer levels
• Evaluating spillway capacity
• Evaluating and planning for tree removal
• Monitoring and developing sheet pile Gap Closure
• Monitoring and planning for the repair of Concrete surfaces
• Inspecting submerged portions of the dam through dive/video inspections
• Updating the project operations and maintenance plan
• Conducting two (4) quarterly inspections of the dam and project structures; including a survey of monuments

Initial work will include surveyors and engineers on-site to measure, document, and photograph the site. Additional work will set reference monuments with hand tools on existing structures. The geotechnical "slope stability" component of this work will require a drilling equipment truck and vehicles on-site to facilitate the installation of water level monitoring devices. Future monitoring will include specially trained divers, who will conduct an underwater dive to inspect subsurface components of the dam. The monitoring work will enable reproducible measurements that when compared can indicate any change or movement in the conditions of the dam.

Funding

$134,600 from the Capital Projects Fund is funding the Union Street Dam monitoring services.