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The City of Portland, Oregon

Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

1120 SW 5th Ave, Suite 613, Portland, OR 97204

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Challenges to Watershed Health

Portland's watersheds face many challenges.

Graphic button: Link to Portland's watershed mapPollution, erosion and other urban challenges affect the health of our rivers and streams. Some challenges, like declining salmon populations, are regional or global. However, many are also local challenges and relate to things like:

  • Old or inadequate infrastructure
  • Poor development choices as the city grew
  • Individual Portlanders’ actions

Challenge  Stormwater runoff from streets and parking lots 

Photo of stormwater runoffWhen it rains in urban areas, water runs off of streets and other hard surfaces instead of soaking into the ground. That stormwater runoff washes pollutants from hard surfaces into streams and rivers.

Solutions include using green infrastructure like trees, rain gardens and ecoroofs to soak up rain, slow down runoff and filter pollutants.

Photo of flooded intersection

Flooding  Challenge

Streams and rivers used to flood regularly. Floodwaters replenished the land and soaked into the ground. Now development has disconnected our urban streams and rivers from their natural floodplains, which leaves water no place to go during high flows. This can mean flood damage to homes, businesses and infrastructure.

Solutions include restoring floodplains and stream banks to more natural conditions.

Photo of erosion


High volumes of stormwater can wash away stream banks, cut down hillsides and damage roads and buildings. Eroded soil washes into streams and rivers, damaging water quality and habitat.

Solutions include using low-impact development and managing stormwater on site when possible.

Challenge  Pollution from yards and homesGraphic of cleaners and garden chemicals

Fertilizers, chemicals, and detergents we use in our homes and on our yards can pollute rivers and streams and are toxic to fish and wildlife.

Solutions include reducing your use of home and lawn chemicals, being careful about what you flush, and naturescaping your property.

Photo of culvert blocking fish passage

Culverts that block fish and water

Challenge15 species of native salmon and other fish found in Portland are threatened or endangered. Many culverts block fish access to habitat in the upper reaches of streams. Other culverts are too small for water to flow naturally, causing water to back up.

Solutions include removing old culverts and replacing them with new ones designed to allow fish to pass and water to flow more naturally.

Challenge   Loss of habitat

Graphic showing loss of habitatFish and wildlife need access to and connections within their habitats for food and shelter. Urban development can disturb habitat networks and prevent fish and wildlife from finding the resources they need to survive. 

Solutions include protecting and restoring valuable habitat areas in the city, and adding trees and other nature to our neighborhoods.

Photo of concrete stream bank


Hardened riverbanks

Rock and concrete walls along rivers and streams leave no place for fish to hide, no way for animals and people to safely access the water, and in some cases can make flooding worse.

Solutions include removing concrete and restoring stream banks to more natural conditions where we can, and protecting the best existing habitat from new damage.

Photo of ivy covering hillside and trees

Invasive species

ChallengeInfestations of invasive plants and animals can damage our parks, forests and streams, and cost a lot to manage. In Oregon, controlling invasive species and the damage they cause costs about $125 million each year.

Solutions include rapid response to manage new invasive species before they become established, and continuing to remove ivy and other persistent invasive plants from our urban forest.