This story will appear in the Summer 2015 issue of Our Big Backyard, a quarterly magazine about parks and nature. Read more stories, plan an outing with a field guide, and find out more about fun nature events and classes. The summer issue comes out at the end of June.
Can a landfill ever become a community asset and natural attraction?
Metro is hoping to find out in North Portland.
For more than 50 years, garbage from the Portland area arrived at the St. Johns Landfill. The landfill closed in 1991 after receiving about 14 million tons of trash.
Now, the landfill – technically part of Smith and Bybee Wetlands Natural Area – is finding new life as St. Johns Prairie. A years-long effort is underway to transform the 240-acre site into a prairie full of native plants to attract Western meadowlarks, streaked horned larks, Western painted turtles and other wildlife.
The overall plan for the site includes building a public trail with views of Mount Hood along the eastern and northern edges of the prairie to connect Chimney Park in the south to Bybee and Smith lakes in the north. For now, the landfill remains closed to the public and continues to be actively monitored.
One of the first steps in the prairie’s restoration began last November with the seeding of 17 acres. This spring, sedges, camas, yarrow, daisies, different types of buttercups and dozens of other types of native plants blossomed.
"I chose a list of plants so that something will be blooming from spring to early fall," said Elaine Stewart, a Metro senior natural resources scientist who is leading restoration efforts at the prairie. "There will be lots of nectar and pollen, and the flowers will emerge at different times of year."
The wildflowers attract insects and pollinators and, in turn, birds and wildlife that feed on them. In particular, Stewart hopes to attract Western meadowlarks and streaked horned larks.
"The Western meadowlark is the state bird, and it’s almost gone from this part of the valley," she said. "Hopefully with the new and improved habitat, we’ll see them."
In recent years, employees at the landfill have maintained the newly created habitat for streaked horned larks. They have also used 2-D and 3-D lark decoys and a recorded loop of calls to attract the birds. The larks, which nest nearby in Rivergate, have visited the site but haven’t stayed to nest, said Therese Mitchell, a landfill and environmental specialist.
"One day when monitoring, while the vocal attraction was playing and the 3-D decoys were out, I saw one streaked horned lark running around the sound system box and jumping up at the decoy closest to the sound system box," Mitchell said. "Amazing! I don’t know if the lark was trying to fight with the decoy or woo it."
The decoys have also attracted their host of predators, including curious coyotes and juvenile bald eagles that chomped at the wooden decoys.
Restoration work at a former landfill comes with unique challenges. For instance, a network of pipes that allows for the safe control of methane and other landfill gases crisscrosses the prairie.
A protective plastic cap covering the landfill sits about a foot and a half below the surface, meaning trees and tall plants with extensive roots are largely out of the picture.
On top of the plastic cover sits a layer of sand and a layer of top soil. The sand and soil, along with the site’s gently sloping hills, ensure water drains quickly in order to minimize the chances of water interacting with the garbage and causing contamination. But those features also cause the soil to dry out quickly, which can make it more difficult for plants to grow.
But the challenges are easily outweighed by the benefits. Restoring St. Johns Prairie continues the transformation of the landfill from a public liability to a community asset, said Paul Vandenberg, principal planner for the landfill.
"We’re continuing to reclaim the landscape through environmental monitoring, habitat restoration and the construction of trails that will allow the public to experience the site again," he said.