Challenges to Watershed Health
Portland's watersheds face many challenges.
Pollution, 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
Stormwater runoff from streets and parking lots
When 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.
Flooding
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.
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.
Pollution from yards and homes
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.
Culverts that block fish and water
15 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.
Loss of habitat
Fish 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.
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.
Invasive species
Infestations 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.