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. Establishing native riparian forest habitat can be challenging. In the summer of 2019, Tree for All partners launched a two-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 reconnects the creek and floodplain while helping to protect the adjacent road and demonstration farm from flood risk.

Gales Stream a B Street Trail Gallery

Work done to reconnect the floodplain in both phases of the project helps to nourish the surrounding forest and wet prairie and enhances habitat for steelhead in the creek.

An incised portion of the creek was widened in Phase 1. Now the creek can more readily rise and flood the forest.

To prevent erosion after construction, field operations crews apply straw to bare soil.

Field operations crew applies special erosion control fabric to the floodplain opening on Phase 2.

A non-functional berm was removed to open up the floodplain.

Wet prairie habitat was created 2013-2018.

B St trail follows an obsolete railroad right of way. This project removed the remnant railroad trestle, which aggravates erosion. (Trestle is visible on the left of this spring 2019 photo.)

Spring, 2019: The obsolete, eroding railroad bed separates the creek from its floodplain. Vegetation from this area, already somewhat sparse, has already been removed to prepare for this phase of construction work. The area will be replanted in the fall and winter of 2019-20, as part of Phase 1.

Native camas flourishes amidst spring rains in a nearby wetland.

The project will reduce streamside erosion, starkly visible in this spring 2019 photo.

The B St trail is a popular destination, easily accessible from Forest Grove yet not far from farms and the foothills of the Coast Range. (Photo: Spring 2019)

In preparation for construction during the spring of 2019, a team of Xerces Society staff and volunteers surveyed and relocated native freshwater mussels, which can live up to 50 years and filter water all their lives. All native freshwater mussels in Oregon are considered sensitive or threatened.

Aug. 20: A creek stabilization project like this requires a lot of logs— and trail closures so it’s safe to truck in the wood.

Aug. 28: This project removed the obsolete railroad trestle.

Aug. 29: Crews used specialized equipment to safely remove the obsolete trestle supports. All in all, about 58,000 pounds of creosote-treated trestle material was safely removed. In addition, the team removed 150,000 pounds of railroad fill and replaced it with good soil.

Sep. 5: Crews used heavy equipment to excavate the work area down to the level of the creek.

Sept. 24: The team placed a special turbidity curtain in the creek to protect water quality, then used a sein net to remove fish and other aquatic organisms from the channel work area. Heavy rains hit early this year, complicating this effort.

Sep. 24: Tree trunks pounded deep into the bank play a critical role in stream stabilization.

Oct 3: Creekbank stabilization involves multiple strategies and materials, including coconut fiber fabric, logs and 6,000 cuttings from native trees and shrubs.

Oct 8: Starting from the bottom and moving up, crews created a total of nine soil lifts to reshape the creekbank.

Oct. 10: As the construction portion of Phase 1 neared completion, construction crews applied 125 pounds of native grass and wildflower seed. Revegetation crews will soon arrive to plant native grasses, wildflowers, shrubs and trees that will ultimately re-grow into a healthy riparian forest, as seen in the background of this photo.

Oct. 15: The project includes some drainage improvements along the trail.

Oct. 21: As the fall rains began, the creek began to rise and interact with the rebuilt bank.

12.20.19 As the creek rose with winter rains, the water moved as the project team intended.

12.20.19 Portions of the path that have historically flooded are staying dry in winter rains, thanks to the drainage component of the project. The team is taking steps to help the public understand how important it is to enjoy the project from the trail and avoid walking on the newly planted areas.

12.21.19 As the December rains continued, the water covered the entire project area, submerging all levels of the rebuilt bank and flowing over the trail and into the area created to hold high flows.

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The Site

First planting: 2008 (entire Natural Area); 2019 (current project)
Size: 3 acres
Stream length: 175 feet
Plant communities: Riparian Forest

Featured

Habitat Connectivity

Recreation and Human Health

Community Involvement

Protects Water Quality

The Challenge

When the project began, this site was home to many challenging features, including two earthen berms and the remnants of a railroad trestle. The berms, built long ago for flood control, didn’t protect the adjacent road or farm from flooding in high water events. They did, however, disconnect the creek from its floodplain, reducing water quality and increasing high-water impacts downstream and upstream. The remnant trestle increased erosion in the creek. In many spots, the creek banks were very steep, with little vegetation to stabilize the banks or cool the water. All 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.

The Transformation

This site is part of the larger Gales Forest Grove Natural Area, where Tree for All partners have been active for more than a decade. In 2019, Metro, Clean Water Services and the City of Forest Grove came together to execute a two-year project to improve water quality, creek stability, fish and wildlife habitat, plant communities and recreational opportunities along this reach of Gales Creek, just off the B St Trail.

Phase 1, August 22-October 15, 2019: Contractors removed the remnant railroad trestle, rebuilt the creek bank to slope more gently and connect with the floodplain, and placed large wood (habitat logs) along the channel and below the creek’s high water line. This phase, which enhanced a total of 1.5 acres, wrapped up with the planting of thousands of native plants, which will help stabilize the creek, shade the water, create wildlife habitat and revegetate an old, unintended trail.

Phase 2, 2020: Phase 2 tackles the remaining 1.5 acres of the immediate project area. On the south side of the creek, a Clean Water Services’ Field Operations crew restored connection to the floodplain by removing about 80 feet of non-functional berm. 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.

Seven large wood structures have been added to the site. Berm material was moved from an ineffective berm to reinforce a berm that helps protect Pacific University’s teaching farm. Planting will follow this winter.

Together, the two phases of work here create habitat that will help to regulate temperature, sediments, and nutrients on Gales Creek, home to the most important winter steelhead population in the Tualatin Valley. And 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 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.