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Johnson Creek Watershed

Information
Photo shows a creek freely flowing over rocks and boulders
The Johnson Creek watershed is the largest drainage basin in the city, and is important habitat for salmon, steelhead, and trout including several threatened and endangered species. The watershed spans 34,560 acres covering parts of two counties and four cities in the Portland metropolitan area.
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About the Johnson Creek Watershed

Johnson Creek starts at its headwaters in Clackamas County, east of Boring, and flows 26 miles west to meet the Willamette River in Milwaukie. The watershed drains about 54 square miles, including parts of Clackamas and Multnomah counties, and the cities of Gresham, Happy Valley, Portland, and Milwaukie. Approximately 40 percent of the watershed is in Portland.

While it flows west, the creek passes through upland forests, farms, neighborhoods, wildlife refuges, and industrial properties. It goes along trails, under roads, and through golf courses. It is a natural refuge in an urban environment, and one of Portland's most important resources.  

History and Flooding

The Johnson Creek floodplain is thought to be a remnant of the Missoula flood. That same flood carved out the Columbia River Gorge and the Willamette Valley 15,000 years ago. Flooding has continued to be a predominant issue in the watershed. The largest flood on record happened in 1964, and a storm in December 2015 caused the highest peak flow recorded in the creek.

Two projects that significantly impacted the watershed's natural hydrology were the construction of the Springwater Rail line in the 1890s and a Works Progress Administration creek project in the 1930s. Both separated the creek from its natural floodplain.

Today, Johnson Creek is critical habitat for many coho and chinook salmon, steelhead, and cutthroat trout listed under the Endangered Species Act. Oregon’s Department of Environmental Quality lists Johnson Creek as a water quality limited 303-d stream. This label is due to: 

  • High temperature (from lack of riparian canopy). 
  • Bacteria (from wildlife, agriculture, and septic systems). 
  • Toxics (primarily from remnant pesticides). 

Learn more about the Department of Environmental Quality's Water Quality Assessment Program.

How the Watershed Is Doing Today 

The Johnson Creek watershed has room to improve. In the most recent report card, the watershed received grades of: 

  • Hydrology – A
  • Water Quality – C
  • Habitat – C+
  • Fish and Wildlife – D+

Review the Johnson Creek Watershed Report Card for more information.

Work We've Done to Improve Conditions

To improve scores, our past and current project focus on: 

  • Restoring floodplain and stream banks.
  • Lowering stream temperatures.
  • Increasing riparian canopy (planting trees along stream banks). 
  • Adding large wood to streams. 

Learn more about the 20 projects completed in the Johnson Creek watershed with the help of many community partners to address environmental issues along the creek. These efforts over the past 25 years help to reduce the risk of flooding and improve the health of the creek to support salmon recovery and a more resilient Portland.

Work We're Doing to Improve Conditions

Current and upcoming stream restoration work includes:

Projects to repair, replace, or extend sewer pipes and to better manage stormwater help protect water quality in the creek by keeping harmful bacteria and pollution out. Find information about all current Environmental Services projects.

Important Fish and Wildlife 

Large populations of salmon used to inhabit Johnson Creek. Salmon numbers declined once urbanization began and there were more streets, roads, and buildings built in the watershed. Salmon populations declined further after the Works Progress Administration project of the 1930s straightened and rock-lined the creek.

Photo of a scientist with gloves holding a long, eel-like fish, called a lamprey
Fish biologists find a Pacific lamprey during a study at a project site along Johnson Creek.

The creek has the highest number of native fish species in Portland streams. Although nine of the 28 total species captured during studies are non-native, 99 percent of all the fish are native. Native reticulate sculpin, redside shiner, and speckled dace are the three most commonly captured fish. Rainbow/steelhead trout and cutthroat trout are regularly captured. Pacific lamprey, western brook lamprey, coho and Chinook are infrequently captured in the creek. 

Rare, red-shouldered hawks have been spotted in natural areas along Johnson Creek. The crow-sized green heron can be seen throughout the watershed, hunting in creeks and wetlands, and flying along stream corridors. The most common birds on stream surveys are song sparrows, robins, and crows. In deeper forest, one may hear the musical song of the Swainson’s thrush (known as “salmonberry bird” to Indigenous tribes). Colorful, silky-plumaged cedar waxwings frequent the watershed as well, sporting their bandit eye-masks and waxy red feather tips. Powell Butte is home to grassland birds rarely found elsewhere in Portland: kestrels, meadowlarks, and Savannah sparrows. 

Johnson Creek also acts as a wildlife corridor for species not always observed in large cities, including: 

  • Deer
  • Coyote
  • Bear
  • Cougar

There are sensitive species living in the riparian areas of Johnson Creek. These include three salamander species (long-toed, northwestern, and Columbia), two frog species, and one toad species. We also see painted turtles in the upper watershed (east of 162nd Street). Other sensitive species have been sighted in the following specific areas: 

  • Salamanders at 162nd and Kelley Creek.
  • Great horned owls, red-legged frogs, hawks, and coyotes at 182nd and Springwater Corridor.
  • Tall bugbane at Powell Butte.

How to Experience the Johnson Creek Watershed 

Take a tour of Crystal Springs Creek in the Johnson Creek watershed to see a vibrant urban waterway supporting populations of threatened salmon and trout species.

How to Get Involved 

The Johnson Creek Watershed Council offers stewardship and educational opportunities. Learn more and find upcoming events on the council's webpage.