A Popular Trail, a Healthy Creek
Gales Creek is one of the Tualatin River’s major tributaries, and Forest Grove’s B Street Trail is a popular place for people to access Gales Creek. Erosion can be a significant problem at this location, as is the meager presence of native vegetation. In the summer of 2019, Tree for All partners are launching a three-year enhancement project just upstream of the B St Trail Bridge that will improve creek stability, water quality and fish and wildlife habitat. The project is designed to reconnect the creek and the floodplain without increasing flood risk for the adjacent demonstration farm.
First planting: 2008 (entire Natural Area); 2019 (current project)
Size: 3 acres
Stream length: 175 feet
Plant communities: Riparian Forest
This small site is home to many challenging features, including two earthen berms and the remnants of a railroad trestle. The berms, built long ago for flood control, don’t protect the adjacent road or farm from flooding in high water events. They do, however, disconnect the creek from its floodplain, reducing water quality and increasing high-water impacts downstream. The remnant trestle increases erosion in the creek. In many spots, the creek banks are very steep, with little to no vegetation to stabilize the banks or cool the water. Any stream enhancement activity in this area needs to avoid increasing the flood risk for the infrastructure that flanks the site: A popular trail with a pedestrian bridge; a major road; and a teaching farm operated by Pacific University as a demonstration site for sustainability initiatives.
This site is part of the larger Gales Creek Forest Grove Natural Area, where Tree for All partners have been active for more than a decade. Now, Metro, Clean Water Services and the City of Forest Grove have come together to plan a three-phase, three-year project that will improve water quality, creek stability, fish and wildlife habitat, plant communities and recreational opportunities along this particular reach of Gales Creek, just off the B St Trail.
Phase 1, Summer 2019: Contractors will remove the remnant railroad trestle; rebuild the creek bank to slope more gently and connect with the floodplain; and place large wood (habitat logs) along the channel and below the creek’s high water line. This phase will wrap up with the planting of thousands of native plants, which will help stabilize the creek, shade the water and create wildlife habitat. To keep people safe during heavy construction, Phase 1 will involve several brief closures of the B St trailhead, as well as a temporary closure the entire B St Trail.
Phase 2, Summer 2020: Clean Water Services will work to restore better connection between the creek and the floodplain on the south side of the creek by building a shallow swale full of wetland plants. During very high water events (typically 2-3 days per year), this floodplain reconnection is expected to result in two changes:
· Water will move more slowly in the creek, decreasing erosion, and
· Water will move through the full floodplain, improving ecological function in that area by providing native plants and wildlife the environment that suits them.
This project is not expected to increase the risk of flooding of human infrastructure.
Phase 3, Summer 2021: After the plants have become established in the shallow swale, CWS crews will remove a portion of the outer berm to let wintertime creek water flow into the swale from time to time. This phase will also include opportunities for volunteers from the Forest Grove and Pacific University communities to plant native trees and shrubs on the rest of the floodplain.
This project will create habitat that helps to regulate temperature, sediments and nutrients on Gales Creek, home to some of the most important winter steelhead habitat in the entire Tualatin Valley. Thanks to the growing network of trails, thousands of visitors will have an opportunity to experience the benefits of ecological enhancement, within easy reach of downtown Forest Grove and Pacific University.
Partners will continue to monitor and manage the plants, streambanks, habitat logs and other elements of the project for at least 20 years. The area is permanently protected as a public natural area. The Gales Creek Forest Grove Natural Area will become an even more valuable hands-on learning site for local students, from pre-K through graduate school, for years to come.