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Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

1120 SW 5th Avenue, Room 1000, Portland, OR 97204

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Linnton Neighborhood Volunteers Go After Ivy Along Hoge Creek

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Funding from the Community Watershed Stewardship Program will help support the project

Watch the transformation of Hoge Creek in Linnton Neighborhood from ivy-covered to lovingly-restored with native plants.  Neighborhood volunteers have received grant funding from the City of Portland’s Community Watershed Stewardship Program and have worked with Portland Parks and Recreation to save mature trees from climbing ivy, remove ivy near the stream and restore the area with native woodland species.

The group has recently been awarded $6,200 to continue the work on a restoration, outreach and pollution reduction project for Linnton Creek in Forest Park. The project will remove invasive vegetation, restore native plants, and install an interpretive sign and a plastic bag dispenser to encourage dog owners to pick up after their pets to reduce pollution in the creek.

The Community Watershed Stewardship Program (CWSP) helps Portlanders make improvements in their neighborhoods and communities, while also improving the health of our watersheds. CWSP is a partnership between Environmental Services and Portland State University. Visit the CWSP website to learn more about stewardship projects and future funding opportunities. 

Three Juvenile Red-tailed Hawks released on the Portland Building Ecoroof

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Three juvenile red-tailed hawks were discovered on downtown streets near the Portland Building recently, apparently having fledged their urban nest a little too early.  The hawks were too young to fly or hunt for themselves, so after a week of rehabilitation at the Audubon Society of Portland’s Wildlife Care Center, they were released on the Portland Building’s ecoroof.  The parents, who were still in the area raising young, spotted the birds and have resumed caring for them - bringing in rats, squirrels and pigeons while the juveniles continue to build their flight muscles on downtown rooftops. 

Ecoroofs do a great job managing stormwater, while they cool and filter the air, reduce costs, and they look good.  Now we know they also make great sites for urban raptor releases!


Photos by Bob Sallinger

An Ecoroof Milestone: Portland Reaches its Millionth Square Foot

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Portland has recently passed the one million square-foot mark for extensive ecoroofs built.   These ecoroofs manage over 23 million gallons of stormwater annually, making our rivers and streams cleaner and cooler while providing a little habitat, and cooling our urban environment at the same time.  Though we’ve been passed by larger cities like Washington DC, Toronto, and Chicago, Portland has seen a slow, steady increase in ecoroof construction since our first was built in 1996. 

Extensive ecoroofs are thin-soiled vegetated roofs which manage stormwater using drought-tolerant plants such as sedum.  They are contrasted with intensive roofs, which have deeper soils, larger plants and often are more garden-like.  We have an additional 750,000 square feet of intensive greenroofs. 


Alien Plant Invader: Milk Thistle (Silybum marianum)

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An update on successful efforts to fight this plant, and what you can do to help

This world traveler comes from the Mediterranean region, but is also found in places like Australia, South Africa, Chile, Pakistan, and Canada, to name a few. Milk thistle is a B listed species in Oregon and is widespread in southwestern part Oregon and the Willamette Valley.

There are several reasons to be concerned about milk thistle. One is that a single plant can produce about 6,000 seeds that can stay viable for nine years! Seeds can spread in many ways including wind, water, mud, vehicles, animals, machinery, agricultural produce, and in flower or vegetable seed packets. Milk thistle will overstay its welcome anywhere it can find fertile soils that are often disturbed. Like many other invasive species, milk thistle will form dense patches that outcompete native plants for moisture, sunlight, and nutrients. One of the worst things about milk thistle invasion is that it accumulates nitrates and can poison cattle and sheep. We don’t want this plant to spread!

While many thistles look alike, the distinctive green and white marbling of the leaves gives away milk thistle’s true identity. The leaves also have spiny margins, are lobed, hairless, and quite large, with leaves at the base reaching 20 inches long. It is an annual or biennial and grows between two and six feet high. Between April and July, a solitary large purple flower emerges at the end of each stem. The flower is typically about two inches across, (though four-inch flowers are possible) and is surrounded by one to two-inch spines. Ouch!

Since milk thistle seedlings require light, the best way to send a “not welcome” message is to plant competing vegetation. It’s also important to remove sources of soil disturbance. If you have a small patch, hand pulling can be effective (watch out for those spines), but you should follow up with planting a native replacement, such as a native perennial grass. Low amounts of herbicide can help control milk thistle as well. Your best chances for successful control are when the plant is still a seedling, or as it grows into a rosette. If you find milk thistle, please contact Mitch Bixby at Environmental Services to discuss options.

Invasive species affect us all. They damage forests, streams, rivers and our property. Nationwide, invasives cause an estimated $120 billion in damages every year. In Oregon, the costs of controlling invasive weeds and the damage they cause amounts to about $125 million each year. It costs a lot less to control new invasive plantsbefore they become infestations, but we need your help. Read more about the problems caused by invasive species and why Environmental Services is concerned about their impact on water quality.

Catch up on previous Alien Plant Invader posts:

Look! An Owl!

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Check out this video of an adult Barred Owl found on an early-morning bird survey

This adult Barred Owl perched near field biologist Adam Baz while he was conducting an early-morning bird count for the Environmental Services watershed monitoring program on June 8.

Environmental Services collects data along rivers and streams and summarizes the information in Watershed Report Cards. We’re working hard to improve the health of our rivers and streams. By tracking how they’re doing, we can see what’s improving and where we need to do more.

We measure birds, fish, and bugs (macroinvertebrates) because they are indicators of overall environmental health. Some bird and fish species are also protected under the Endangered Species Act or are at risk of becoming threatened or endangered.