Why Wetlands Matter: Restoring a Small Creek Makes a Big Impact for the Local Community
By Dana Bivens, a Public Affairs Officer for the U.S. Fish and Wildlife Service
Wetlands are essential for ecosystems. They offer important habitat for waterfowl, fish, frogs, beavers, and many other species. They also provide a lesser-known benefit to humans by cleaning the water we drink. These unassuming, marshy habitats are in fact instrumental in removing dangerous pollutants from an ecosystem.
When it rains, moisture falls to the earth and travels downhill into streams and rivers. On the way, it collects whatever is in its path. From dirt and garbage to excess fertilizer on lawns and oil from cars on the streets, urban runoff can wreak havoc on the environment. Excess nutrients from fertilizer cause algal blooms that create low oxygen zones in ponds, lakes, and oceans. These low oxygen areas suffocate aquatic wildlife and plants, killing fish and decimating submerged aquatic vegetation. Sediment trapped in the water column blocks sunlight from reaching underwater plants, causing them to wilt and die. This deprives many organisms of food and shelter, leading to further population declines. Chemical contaminates from pesticides, motor oil, and other substances are harmful to human, plant, and animal health. In short, runoff poses a major threat to all living creatures in a watershed. Restoring healthy wetland ecosystems can go a long way to minimize the effects of urban runoff.
What is a wetland and why are they important?
A marsh or wetland is an area where water floods lowlands, leaving vegetation partially or completely submerged in shallow water. Wetlands can be seasonal or permeant but are characterized as a transitional stage between a waterway and upland habitat. When water flows from a stream and into a wetland, it spreads out and slows with the help of submerged and emergent vegetation. The slower water velocity and vegetation helps to trap sediment and pollutants carried through runoff, removing them from the water. Wetland plants also help to absorb nitrogen and phosphorus, which are common pollutants from fertilizer use. As water leaves a wetland it is cleaner, and these ecosystems help to improve habitat and water quality for all users downstream. Marshes are so effective at cleaning water that many municipalities rely on them as a primary method for purifying this vital resource for homes and businesses.
How is the Service working to restore wetland habitats?
A few miles from Portland, Oregon, the U.S. Fish and Wildlife Service recently completed a wetland restoration project at Tualatin River National Wildlife Refuge. This project was designed to help the refuge’s many animal residents while also supporting water quality initiatives for the surrounding community. The 1,400-acre refuge sits within the watershed of the Tualatin River and is surrounded by the homes and businesses of Tualatin, Tigard, King City, and Sherwood, Oregon. The urban refuge is a sanctuary for local wildlife in need of wetland and lowland habitat that has slowly shrunk due to expanding urban development. Additionally, this natural oasis offers visitors a chance to escape the hustle and bustle of the Portland metro area without having to travel far from home.
Prior to its establishment in 1992, the refuge lands were used for agricultural production, which dramatically changed the natural landscape. Chicken Creek, which runs through the western portion of the refuge before connecting with the Tualatin river, was straightened and channelized to help drain the land for crop growth and dairy farming, and to provide irrigation water during dry summer months. These channels syphon water from the land and have high sides that prevent seasonal flooding needed for wetlands to thrive. In addition to changing the ecosystem’s hydrology, agricultural channels make poor wildlife habitat. Fish, frogs, and other animals need meandering waterways and debris such as rocks and fallen trees behind which to hide from predators and forage for food.
In 2018, refuge staff started working on a plan to return Chicken Creek to its original path and create more wetland habitat on the refuge. In addition to reestablishing the stream, the plan called for the removal of a road and culverts that bisected the wetland. Removing this road would allow water between two sections to flow naturally, further expanding the marsh. In total, the project would restore 280 acres of contiguous wetlands on the refuge, expanding habitat for waterfowl and other wildlife. The restored stream with improved habitat and fish passage will also support cutthroat trout, Coho salmon, lamprey, and many other iconic species. Visitors will be able to view wildlife from an extended trail network that circles the wetland, and the community will benefit from cleaner water at a fraction of the cost of a wastewater treatment plant.
The restoration project broke ground in 2019. The first step was the cut a new stream trail that followed its historical path. To accomplish this, the refuge brought in heavy machinery to dig a new, winding channel. Workers then placed fallen trees among oxbow turns and soft bends to provide critical sheltering habitat for aquatic species. Before redirecting the water into the restored pathway, however, teams of biologists and volunteers removed the existing aquatic wildlife from the old agricultural channel. Over multiple stages, wader-wearing volunteers and staff armed with nets and buckets gently caught thousands of animals including crayfish, cutthroat trout, and freshwater mussels. In total, nearly 3,000 animals representing nineteen different aquatic species were caught before staff redirected the water to the new stream. Volunteers then released the rescued wildlife upstream, unharmed.
The old half mile agricultural ditch was replaced with nearly two miles of meandering stream that winds its way among rose spirea, red osier dogwood, and nine bark in the refuge lowlands. Refuge staff and volunteers also planted willows, sedges, and federally listed Nelson’s checkermallow to restore native vegetation in the wetland. The return of Chicken Creek’s natural flow has already begun to attract a variety of creatures that historically called this marsh home. Ducks and geese are feeding in the marsh, and beavers are actively building dams, which helps to create even more lush, diverse wetland and riparian habitat along Chicken Creek.
Next, workers removed a road and culverts which separated two sections of the refuge lowlands. The raised road would have blocked waterflow between the areas on either side, so by removing it, the entire 280-acre wetland is connected and continuous. In addition, workers used cranes and heavy machinery to dismantle two water control structures on both ends of the restored stream channel. Removing the culverts, road, and water control structures was the final step in improving fish passage and returning the wetland habitat to its original state.
Restoration work was completed in the fall of 2021, and water is already flowing through the refuge lowlands. Over the winter, volunteers will plant thousands of trees and shrubs to help stabilize the banks and create ideal riparian habitat for wildlife. By spring 2022, visitors to the refuge will be able to enjoy the expanded trail that encircles the newly restored wetland. Totaling 3.6 miles with two new bridges, this trail offers great wildlife viewing opportunities for local residents and visitors. School groups will also be able to come and learn about wetland ecology and see the habitat and the wildlife it attracts firsthand.
Partnerships make conservation possible
Restoration projects like this wouldn’t be possible without the time, effort, and support of our many partners. Clean Water Services, Friends of the Tualatin River National Wildlife Refuge, Willamette Water Supply, Ducks Unlimited, Oregon Department of Fish and Wildlife, and the Tualatin Soil and Water Conservation District all worked together to build back a better wetland for the community and wildlife. Restoring Chicken Creek benefits local wildlife, cleans water for the community, and gives visitors an outdoor recreational outlet in a crowded urban center. The value of our natural ecosystems and the benefits they provide are multifaceted and investments in conservation often give back many times over. Partnerships make conservation possible and when we work together, we can do amazing things for wildlife and the community.