Clarification appended

Greenway Park used to have a beaver or two living along Fanno Creek, which winds through the area, and the park-goers and animals lived in harmony.

But now a family of beavers calls it home and they're flooding the park. The beavers have dammed Fanno Creek, and Tualatin Hills Park & Recreation District gated off a loop section of the flooded trail at least six months ago.

Even after several days of dry weather, the trail remains underwater. The main trail takes walkers and bikers around the high water but, lately, it's been flooding, too, when it rains, said James Wilson, a frequent trail user.

Wilson said he has watched the park, which has playgrounds, basketball courts, tennis courts and disc golf as well as an extensive trail system, transform into a lake over the last three years.

"Beavers are cool animals but you can't let them destroy the thing," he said. "This is not a lake, it's a park."

THPRD was waiting to see if Fanno Creek would wash away the dams, said Bruce Barbarasch, superintendent of natural resources and trails management. But that hasn't happened, and the park district is considering other options.

Barbarasch said THPRD could let nature run its course and make a portion of the park a wildlife area. Other options could include rerouting the flooded trail or building a boardwalk or bridge over the area.

Building a new trail or a boardwalk, however, is expensive and the park district doesn't have funding for it at the present time, he said.

Nearly 100 percent of Greenway Park is in a flood plain, Barbarasch said.

Asked why THPRD would build trails in a flood plain, he said the park was developed decades ago and, "there is only so much usable space."

The park district has heard from people on both sides of the beaver issue, he said. Some people want the beavers to take up residence. Others believe taxpayers should have full use of the park.

On a sunny Tuesday at noon, dozens of people walked the trails while others played disc golf and kids climbed on the playground structures.

"There's no reason they (THPRD) can't find a way to make it work for both," said Mike Barrett, who walks the park daily during his lunch break.

He has bypassed the gated portion and entered the closed trail, as have many people, and has seen the telltale pointed tree stumps gnawed by beavers. He described some as "huge."

"We had a beaver here for years and we coexisted," Barrett said. "This year, the beavers have blossomed."

Wilson worries about the park infrastructure, paid for by taxpayers, getting destroyed. After several dry days, water in Fanno Creek was high enough to hit the bottom of a walking bridge, and Wilson said it covers the bridges when the water rises on rainy days.

He wants the park district to break up the dams and let Fanno Creek flow its natural course again, let the beavers rebuild and break up the dams when the water reaches a certain flooding level.

Beavers are making a comeback in their namesake city and they're good for creating habitat for other creatures and helping with water quality, Barbarasch said.

According to National Geographic, Beavers are 60-pound plant-eating rodents that prefer to burrow in the banks of rivers and lakes. They build dams in "less suitable habitats" to create ponds where they live off aquatic plants, roots, barks and leaves. They're famous for their flat tails, which they slap on the water to warn of danger.

"Beavers are second only to humans in their ability to manipulate and change their environment," according to National Geographic.

Barbarasch said THPRD will consider their options this spring, get thoughts from the public and evaluate the best approach.

Clarification: The flooded portion of the trail is a loop of the main trail. The main trail itself is not flooded.

-- Wendy Owen

503-294-5961