Wildlife habitat is a precious resource in the Tualatin River watershed and Washington County is one of the fastest growing counties in the state. While more people are finding a new home alongside our river, streams, and forests, there is increasing pressure to pave and build on wildlife habitat. At Tualatin Soil and Water Conservation District (Tualatin SWCD), we put targeted funding towards the preservation and enhancement of key wildlife habitats, one log at a time.
Tualatin SWCD is charting a new course for a stream south of Cornelius. The stream flows northeast through farms and nurseries, between the greens of a golf course, and under roads before reaching the Tualatin river. The name of the stream is Fern Creek, a designation only recently approved by the U.S. Board of Geographic Names in the spring of 2022 at the request of local landowners. Our work to enhance the stream is multi-pronged, meant to benefit the aquatic, wetland, and upland forest habitats at the site.
The goal of the project has been to remedy missing habitat elements.
At the beginning of the project in 2018, Fern creek was degraded. Steep banks disconnected the stream from its floodplainFloodplain Low-lying land adjacent to a body of water that is susceptible to flooding or prolonged wetness. and lack of shade from trees and shrubs made the creek too warm to support aquatic wildlife. The stream also followed an unnaturally straight path.
When streams aren’t interrupted by beaver dams, plant roots, fallen trees, and other elements of a healthy plant and wildlife community, the water can become damagingly powerful. With too much energy, water carves out soils from the streambank and carries away unfiltered pollution and sediments. In these conditions, water moves too quickly to benefit the floodplain or interact with groundwaterGroundwater Water held underground in the soil or in crevices of rock., and it worsens downstream flooding. A healthy stream is dynamic: the stream is connected to its floodplain and water will spread out (flood) when levels are high, allowing gravel and soil to build up creating islands of vegetation, shade, and habitat for wildlife.
To enhance the floodplain and the stream:
- We’ve intentionally placed logs and felled trees to change the course and speed of the water to:
- Encourage the water to naturally replenish groundwater stores
- Expand the wet areas to make the floodplain hospitable to plants and wildlife
- Reduce erosion on site and downstream
- We’ve treated invasive species and are adding over 75 species of native plants to welcome wildlife and support a biodiverse ecosystem.
The site was first treated to allow native plants to gain a foothold over weeds.
The stream and floodplain had little plant diversity when we first reached the site. As visible in this picture, much of the floodplain was dominated by Reed canary grass. This invasive plant creates a challenging mat of dead grass and roots that stop new native plant seeds from establishing. We treated the invasive weeds in the spring of 2019 and each winter since we have added more native plants to the site.
We didn’t need to look too far for the wood we needed.
A densely planted douglas-fir forest stands just uphill from Fern creek. In timber settings like these, trees are planted close together to encourage quick growth to outpace any weeds. Years later, smaller and unhealthy trees are selectively removed before harvest. We thinned this overstocked forest which has two benefits. Now thinned, the remaining trees have room to grow and more sunlight reaches the forest floor to provide light to the understoryUnderstory The layer of plants that exists closer to the ground under large trees. plants we’ve installed. Also, thinning provided a local source of wood for the project, reducing project costs and energy consumption.
Thousands of plants have been planted and seeded.
A variety of native plants were selected that would benefit a diversity of wildlife: welcoming beaver to create ponds, providing food and homes for birds, and encouraging insects that would benefit, not harm, the neighboring blueberry farm.
| Smaller plants were introduced as seeds: American slough grass, willow dock, Tufted hairgrass and Water foxtail, for example. | |
| Larger plants went into the ground with a thin stem and bare roots: Piper willow, Sitka willow, Douglas spirea, Common snowberry, Red osier dogwood and Swamp rose, for example. |
We are in the middle of an ongoing, multi-year project.
When completed our project will result in 28.5 acres of restored floodplain and wildlife habitat. We expect to see ongoing transformation with winter rains, modifications by beaver, and new plants.
This project would not be possible without the enthusiasm, support, and permissions provided by the landowners, Alan Jesse, President at Forest Hills Farms and second generation farmer and Anna Jesse, Vice President at Forest Hills Farms and third generation farmer, and Tualatin SWCD Board Director.
We thank our contractors in this work who have contributed their expertise to ensure a successful project: D. Franco Restoration Inc., Biohabitats, & GeoEngineers Inc.
