Small Dam Removal Provides Big Benefit for Fish
Gales Creek winds for more than 50 miles through western Washington County, offering some of the best fish habitat in the region. But 12 miles upstream from where Gales Creek joins the Tualatin River, an obsolete, three-foot-tall dam at Balm Grove has impeded fish passage for decades, blocking access to more than 35 miles of high-value spawning habitat. Gales Creek, alone in the Tualatin Valley Watershed, is recognized as critical habitat for winter steelhead, an anadromous (migratory) fish listed as threatened under the Endangered Species Act. The creek is also home to cutthroat trout and lamprey, as well as anadromous coho salmon, which travel hundreds of miles during their lifetime and eventually return to their birth streams to lay their eggs.
Size: 12 acres
Stream length: 1,167 feet
First planting: planned for 2020 or 2021
Five decades ago, Balm Grove Dam was built to create a swimming and boating area north of Forest Grove. Over time, however, after zoning and ownership changes, the site ceased to function as a recreational facility. Yet the dam remained in place, creating a bottleneck between the stream’s upper and lower reaches.
By raising water temperatures and altering flows, the dam has a negative effect on all fish species in Gales Creek. Additionally, the dam functions as a physical barrier to all but the strongest of the anadromous fish. The more that Tree for All partners learned about the dam’s effect on fish passage, the more concerned they became. Clean Water Services (CWS), Tualatin Riverkeepers, Tualatin River Watershed Council, Oregon Department of Fish and Wildlife, and Metro all declared the Balm Grove site as a top restoration priority.
In 2016, the family that owned the property that includes Balm Grove Dam sold it to CWS. Metro and the Tualatin Soil and Water Conservation District committed money toward the purchase. CWS then embarked upon project planning, to develop a design for riparian restoration; a determination of full versus partial removal of the concrete dam; decisions about adjustments of the channel bed and banks; and a strategy for long-term stewardship of the site.
In 2017, CWS launched a geomorphic assesment of the stream, to help predict and guide the stream's response to dam removal. Site preparation, including mowing and the removal of undesirable plants, has begun. 2018 is a year of preparation, including project design, permitting and contracting, along with continued removal of invasive plants.
Dam removal could begin as early as the summer of 2019 and could last two summers. Revegetation is expected to begin in 2020 or 2021 and last several years. In the long term, partners will monitor conditions in and around the stream, making adjustments as needed to promote ecological health.
Other current activities at the site include the Tualatin River Watershed Council's continued community outreach and fish-monitoring activities, and a community science/student education program through Portland State University's Student Watershed Research Project. Through SWRP, high school students are learning about the watershed while building a long-term water quality data set that will help provide insights about stream condition, ecology and biodiversity.
This project will open up more than 35 miles of prime habitat to cutthroat trout, coho salmon and winter steelhead. Since a stream that’s healthy for fish is healthy for recreational activities, the project is expected to increase birding, fishing, hiking and camping in the public lands along upper Gales Creek. Tree for All partners are excited that removal of the Balm Grove Dam—the single most important step that our community can take to directly benefit aquatic life in the Tualatin River Watershed—is finally within reach.