Balm Grove Dam Removal

On beautiful Gales Creek, at the Balm Grove site, partners are coming together to accomplish a long-held community goal: Removal of a small dam with a big impact to fish in Gales Creek and the larger Tualatin River Watershed.

History of Balm Grove Dam:

The Balm Grove Dam, a small, obsolete concrete structure located in Gales Creek, 12 miles upstream from where the creek joins the Tualatin River near Forest Grove, has been impeding fish passage for generations. This dam has blocked access to critical spawning habitats for species such as coho salmon, winter steelhead, mountain whitefish, and the endangered Pacific Lamprey. In response, local conservation organizations including Tree For All, Clean Water Services, the Intertwine Alliance, Metro, Northwest Steelheaders, Oregon Department of Fish and Wildlife, Trout Unlimited, Tualatin Riverkeepers, and Tualatin Soil and Water Conservation District have prioritized its removal. The project aims to restore fish populations, benefit wildlife, and return Gales Creek to its natural state.

Historically Balm Grove Dam was a popular recreational area that dates to 1936 when the dam was initially built for swimming. However, as the area ceased functioning as a gathering spot, the dam remained, posing safety hazards, and blocking fish passage. In 2016, Tree for All partners purchased the property to remove the dam and restore the creek. After several years of community outreach, revegetation efforts, and site surveys, a team of experts developed plans for the dam's removal, aiming to restore the natural flow of Gales Creek. This effort is part of a larger, community-driven project to improve the overall health of the Tualatin River Watershed, benefiting not just fish populations but the entire ecosystem.

In summer 2022 the Balm Grove Dam was removed, opening 35 miles of upstream habitat. For more information about the removal of Balm Grove Dam, visit Tree for All.

Pacific Lamprey:

Pacific Lamprey (Entosphenus tridentatus) hold significant cultural value for Indigenous tribes in the Tualatin River Basin, including the Confederated Tribes of Grand Ronde. Historically, Pacific Lamprey were a vital food source and held cultural significance, providing essential nutrients during times of scarcity and fostering strong cultural bonds. Beyond their role in traditional diets, lamprey are seen as symbols of ecological balance and interconnectedness within their communities. Ecologically, Pacific Lamprey contribute to the health of river systems by supporting the food web and nutrient cycling. However, due to habitat degradation and migration barriers like the Balm Grove Dam, their populations have declined significantly. Collaborative restoration efforts involving local tribes and conservation groups are now focused on improving fish passage and restoring habitats. These initiatives not only seek to recover lamprey populations, but also to honor and preserve the cultural heritage tied to this vital species.

Dams, such as the one at Balm Grove, pose a significant barrier to Pacific Lamprey by obstructing their migration routes and disrupting their life cycle. Unlike salmon or steelhead, lamprey lack the ability to leap over obstacles, making dams impassable for them. These barriers block access to essential spawning and rearing habitats, leading to reduced reproductive success and smaller populations. Additionally, the altered flow and water quality conditions caused by dams further degrade the environment that lamprey depend on. By removing the Balm Grove Dam, the project is expected to open up approximately 29 miles of habitat to winter steelhead, over 25 miles to coho salmon and Pacific Lamprey, and over 87 miles to coastal cutthroat trout, along with significant benefits to mountain whitefish and sucker species. In addition to improving fish passage, the removal will enhance sediment and wood transport, water quality, and native plant communities, ensuring the restoration of the creek’s ecological balance and connectivity.

The Tualatin River Watershed Council has been monitoring Pacific Lamprey populations in Gales Creek using eDNA (environmental DNA) sampling since before the removal of the Balm Grove Dam. eDNA is a method that detects genetic material organisms leave behind in their environment, such as in water or soil, allowing species identification without direct observation. Before the dam’s removal, no Pacific Lamprey eDNA was detected upstream of the dam. However, in the first year after the dam was removed, Pacific Lamprey eDNA was detected just upstream of the former dam site. By the second year, Pacific Lamprey eDNA was found 8 miles upstream on the mainstem of Gales Creek, indicating a significant restoration of habitat and fish passage following the dam removal.