Watershed Restoration Recovers Watershed Health and Functions

Information
Photo shows a stream with rip-rap along banks and large rootwads in the water with a neighborhood street in the background.
Watershed restoration leads to cleaner water, builds community resiliency, and makes Portland healthier and more livable for people, fish, and wildlife. Restoration work restores the functions that communities rely on from natural systems (aka nature).

What is Watershed Restoration?

Watershed restoration strives to repair the damage done to our environment and natural systems (like rivers and streams) by poor development choices and human activities. Restoration projects:

  • Help manage stormwater to improve water quality in rivers and streams.
  • Reconnect and restore floodplains to reduce flooding and protect people and property.
  • Support salmon recovery by removing culverts and other barriers for threatened and endangered fish.
  • Improve habitat in and around a stream to help reduce water temperatures and create places for plants, fish, and wildlife.
  • Build community resiliency, which will make our community better prepared to deal with wetter winters and hotter, drier summers.

One Project, Many Benefits

Each dollar spent on watershed restoration generally results in several improvements to watershed health and benefits for people, fish, and wildlife. Read more about why healthy watersheds are important for our community. For example, when we restore a floodplain and reconnect it with its creek, we help protect people and property downstream from the damage caused by flooding. But that work also can:

  • Create habitat for threatened and endangered fish like salmon – giving them a place to find food and rest.
  • Provide protection for young fish from a fast-flowing, turbulent stream.
  • Replenish groundwater, which flows into the creek during the hot summer months replenishing the creek and helping to keep the water cooler.
  • Reduce erosion around and into a stream, which helps protect water quality but also can prevent landslides and property loss.
  • Add back into the landscape native plants, which native animals have relied on for food and shelter for centuries.
  • Increase the number of trees in the riparian area – the area of land along the edge of the creek – which is essential to keeping streams cool and for adding large wood into a stream later. Read more about this below.

Just like trees, the benefits from these projects build and grow each year. Over time, we see more fish going farther upstream. Native plants and trees spread more seeds to establish more native plants. More trees by the stream provide more shade and cooler water temperatures making it better for fish. Over time (often decades), the benefits from restoration re-establish the natural cycle that had been lost.

Find Restoration Projects

Along with the help of many partners, Environmental Services has completed and is working on many watershed restoration projects around Portland. Learn about current and future Environmental Services projects. Find information about past projects that are now part of our watershed monitoring activities.

Explore completed watershed restoration projects that are currently being monitored by Environmental Services.

What Does Watershed Restoration Look Like?

Stream and Wetland Restoration

Photo shows a stream with rip-rap along banks and large rootwads in the water with a neighborhood street in the background.
Stream restoration can include restructuring the stream channel, removing pipes or other efforts to control it, and allowing it to flow more naturally and spread out when water is high. 

We need our natural systems like wetlands, soils, and streams to collect and transport much of our annual rainfall. They work together with our pipe system to protect people and property. But rivers and streams do more than just carry water. They are also home to fish, birds, and wildlife. And, we are required to protect water quality and drinking water supplies for generations to come.

Aerial photo of wetlands with several ponds visible
Wetlands are "the kidneys" of the landscape. They store water and filter out pollutants while providing habitat for animals.

Wetlands are special ecosystems that lie at the intersection of terrestrial (land) and aquatic (water) systems. They are often described as “the kidneys of the landscape” because they filter out pollutants to improve water quality. Wetlands play a critical role in the water cycle. They collect and hold water to prevent flooding. To grow, wetland plants take in elements like nitrogen and phosphorus that could pollute and harm rivers and streams in high amounts.

Stream and wetland restoration aim to restore those functions lost through poor development choices. Projects can include:

  • Restructuring a stream channel to remove development – like buildings built next to the stream or in the floodplain – and prior attempts to control its flow. This allows the stream to flow more naturally.
  • Removing culverts or other structures that constrict stream flow and cause water temperatures to rise or block fish from swimming through.
  • Removing buildings or streets from a floodplain to give a stream space to spread out and reduce downstream flooding.
  • Creating backwater channels or ponds to create habitat for fish and wildlife.
  • Excavate fill from wetlands. Many wetlands were filled with rock and dirt in order to make it possible to build on them. Removing the fill provides more storage for stormwater, while creating habitat for wildlife, including birds and amphibians.
  • Replanting wetlands and stream banks to improve shade, plant diversity, and habitat for wildlife.

Removing Fish Barriers

Photo shows before image with a creek flowing out of a small round pipe under a street next to an after photo, which shows the same creek flowing under a bridge.
This culvert replacement at SE Bybee Blvd was the last culvert replacement along Crystal Springs Creek. Now fish have an open path from Johnson Creek to the lake and that prime habitat upstream.

Structures like culverts under streets or dams in a stream can block salmon and other aquatic species from reaching habitat they need. These structures can also cause erosion, make temperatures in a stream rise, or cause such powerful flows that fish cannot swim through. Removing culverts can open up crucial habitat for salmon and trout that has been blocked for decades.

Stream Daylighting

Photo shows a green space in the park with lots of trees and plants with a path running around the outside of it.
For more than 75 years, a stream flowed through a pipe under part of Spring Garden Park. In 2013, Environmental Services "daylighted" or brought the stream back to the surface where it can now collect and filter stormwater while providing habitat.

As Portland made space for streets and buildings, we buried many streams underground in pipes. Buried underground, the stream cannot support fish and wildlife. In pipes, water flows too fast and can cause erosion when the water rushes into the stream.

Daylighting a stream means removing the pipe, returning the stream aboveground, and allowing it to flow naturally. Then, it can again provide critical habitat for fish and wildlife.

Revegetation

Photo shows a close up of purple lupine in front a creek with a bridge in the background.
At Foster Floodplain Natural Area, lupine blooms each spring. Native trees and plants are critical to restoration and support populations of native birds and wildlife.

Plants provide habitat, soak up rain, cool and clean the air and water, and provide food for fish and wildlife. Restoration almost always involves revegetation: the process of removing nuisance or invasive plants and replanting with native trees, shrubs, and groundcover. Native plants provide food and habitat for our local insects, many of which spend much of their lives in our city’s streams and become food for native fish and wildlife. This cycle helps to keep our streams and rivers healthy.

Adding Large Wood

Photo shows still waters of the Columbia Slough with large trees with rootwads resting in the water.
Many of Portland's creeks and streams lack large wood that can create pools and refuge for fish while attracting the insects they eat for food.

Logs and other large pieces of wood in a stream provide food and refuge for bugs and fish. Large wood creates pools and prevents erosion. In streams, it collects sediment and stores organic matter like leaves that becomes food for bugs, which become food for fish.

When the Project is Done, Monitoring Begins

Once completed, Environmental Services watches over the restored area. Restoration takes time – years and more often decades. During that time, our monitoring team tracks its progress, checks for restored watershed functions, and makes adjustments when and where needed. Learn more about how we take care of the site after restoration to make sure it’s on the right track.