PLT30 - Restoration and Innovation: The FishPass project on the Boardman-Ottaway River

Abstract Description: The Boardman-Ottaway River, a vital tributary to Lake Michigan, has undergone significant restoration to address historical logging and dam impacts. Covering a watershed of 291 square miles and contributing one-third of Grand Traverse Bay’s water volume, the river’s ecological health is crucial. The FishPass project represents the culmination of a 20-year restoration journey aiming to reconnect 211 miles of river while balancing ecological and infrastructural needs.

Historical interventions, including the construction of the Union Street Dam in 1867 and upstream dam removals (Brown Bridge Dam in 2012, Boardman Dam in 2017, and Sabin Dam in 2018), have paved the way for this innovative project. FishPass addresses the “connectivity conundrum” by striving to maintain a free-flowing river while preventing the spread of invasive species such as sea lamprey.

The Union Street Dam, located 1.1 miles upstream of West Grand Traverse Bay, presents unique design challenges. The project must navigate environmental contamination from the former Traverse City Iron Works foundry and relocate critical utilities.

Key elements of FishPass include the Arced Labyrinth Weir and the Fish Sorting Channel. The Arced Labyrinth Weir, with its compact footprint, meets desired rating curves and provides a complete barrier to fish passage while handling a variety of flow conditions. It maintains a constant upstream pool elevation and includes a 6-inch overhang for sea lamprey control. The Fish Sorting Channel ensures safe passage for desirable fish species and incorporates a gantry crane, data carriage, and stoplogs for research manipulation, providing the opportunity for progressive invasive species research on the Great Lakes.

The process used to select and configure fish sorting tools will follow an approach inspired by material recycling, emphasizing automation and integrating multiple technologies targeting sortable attributes of fish (phenological, morphological, behavioral, and physiological). FishPass will operate as an adaptive management project where researchers will annually assess fish communities and habitat use above and below the facility, apply different treatments to optimize fish sorting and passage efficacy, and adapt operations to maximally benefit the watershed and accommodate stakeholder desires.

A construction progress update through August 2025 will highlight milestones achieved to date.

The FishPass project restores ecological connectivity while also showcasing innovative engineering solutions to complex environmental challenges. This project stands as a model for future river restoration efforts, balancing ecological integrity with infrastructure resilience and opening doors for key invasive species research.