Remeandering: A Chance to Revisit Choices Made Decades Before
Fanno Creek originates in Portland’s West Hills, and runs through the city of Tigard from its northern border with Beaverton to its southern edge at the confluence with the Tualatin River. In the 1970s, while installing a sewer pipe in preparation for the coming population boom, the Unified Sewerage Agency (now Clean Water Services) straightened a short reach of Fanno Creek just south of Main Street. For decades after this intervention, the once-meandering, now ditch-like creek was not only unnatural looking but also ecologically unstable.
By the early 2000s, Clean Water Services and the City of Tigard had identified creek remeandering as a priority. Yet it took more than a decade to align the resources to make the project happen. Today, thanks to the actions of Tree for All partners, a healthier and more naturally flowing stream runs through Fanno Creek Park, making positive contributions to the economic, ecological and community health of downtown Tigard.
First planting: 2019
Size: 6.5 acres
Stream length: .25 miles
Plant communities: Riparian forest, scrub-shrub wetland
Without natural curves to help dissipate the energy of the flowing water, this portion of Fanno Creek became prone to erosion. Invasive plants and poor water quality followed, as did trails prone to flooding and at risk of crumbling into the creek. During high flows, a pedestrian bridge that obstructed creek flow contributed to the trail flooding. While the creek itself was straight, there were considerable twists and turns in the path between identifying it as an ecological enhancement priority and actually breaking ground on a project.
In 2007, the City of Tigard and Clean Water Services began to lay the groundwork for what would become known as the Fanno Creek Remeander project. The goal was to reduce erosion, thereby improving water quality, wildlife habitat and the pedestrian experience in Fanno Creek Park between SW Ash and SW Main streets. Almost a decade later, the timing was right and the resources were aligned to embark upon a project that would:
Create a better-functioning channel for Fanno Creek, closer to what it would have been before it was straightened.
Improve floodplain wetlands and streambanks through revegetation of native riparian and wetland plants.
Replace the Ash Street pedestrian bridge with a new one that gives both people and water more room to move.
Add an overlook and pedestrian/bike trails that follow Fanno Creek.
As is true with most Tree for All projects that involve construction in streams and rivers, most of the on-the-ground activity needed to take place during the “in-water work window” that, in our area, begins July 15 and runs through September.
Construction, which began and ended in the summer of 2018, involved excavating a new channel, filling the old one, replacing the pedestrian bridge, and putting in place short-term approaches to stabilize the streambanks for the winter between construction and revegetation. For example, some of the streambanks were constructed of soil lifts: Layers of soil wrapped in coconut fiber blankets, with dogwood branches placed horizontally between them.
In the spring of 2019, revegetation will begin. As they have at hundreds of other Tree for All sites, professional forestry crews will install bareroot trees and shrubs, as well as a diverse array of native herbaceous species – all carefully chosen to stabilize the creek banks and create important wildlife habitat. In time, they will mature into a plant community that prevents erosion, shades the creek, provides habitat, and adds to the aesthetic appeal of the area.