At Fernhill Wetlands, reshaped lagoons to become fertile habitat for wildlife
In just two years, Clean Water Services turned a two-acre asphalt parking lot into a lush wetland that doubles as a wastewater-treatment facility.
The magical marsh was on display last Saturday, when about 100 people attended the annual Birds & Brew festival at Fernhill Wetlands on Forest Groves southern edge.
We had huge, huge tours, said Sheri Wantland, public involvement coordinator for CWS. Lots of young kids, teenagers.
But the two-acre Lower Treatment Wetland is just the first act, a model for what CWS officials hope to do with the more highly visible South Wetland 90 acres that were once home to three sewage lagoons, thousands of birds and hundreds of bird-watchers every year. That all stopped last May, when CWS drained the lagoons and began reshaping them.
The earth-moving finished last Friday, just ahead of this weeks rains, which are the first step toward refilling the now heavily contoured basin. Workers will install heavy pipes and other hydraulic structures over the next few weeks.
By the time the rainy season ends next summer, the new, improved wetland should be full of water again.
According to Wantland, the redesign aims to meet the wastewater-treatment needs of Forest Grove and Cornelius as the cities continue to expand. With the help of a few other cutting edge purification projects, the wetland will keep treatment costs down while also drawing more wildlife.
As the water-resources management utility for the Tualatin River watershed, Clean Water Services not only treats wastewater and manages flood-protection projects, but also maintains healthy rivers and streams for both people and wildlife. Habitat improvement is part of its mission.
Still, the success of the two-acre Lower Treatment Wetland surprised even the people who created it.
It was pretty exciting to see so many species come into an area that used to be a parking lot. Pretty impressive, said Jared Kinnear, the recycled-water program manager who helped engineer the transformation.
Treatment wetlands are usually designed with a flat bottom, Kinnear told members of the Clean Water Services Advisory Commission during a tour last Wednesday, Oct. 8. We did the opposite.
Thats because flatness encourages monoculture crops, which are ideal for farmers, but not for wetlands, where they support only a few species of animals.
So before CWS filled the wetland-to-be with water, a bulldozer dug into the flat ground and furrowed it, letting species that like wetter conditions germinate at the bottom of the furrow while others staked out the top.
The idea was to get diverse plant cover and lots of it so the shade would cool the water.
It worked. Instead of the usual monocultures found in treatment wetlands, Kinnear said, last year we had 23 wetland (plant) species and 80 percent cover. This year we had 36 species and 95 percent cover.
The 13 new species this year all came in as volunteers, Kinnear said, their seeds inadvertently carried by ducks and other birds. Less than one percent were invasive species such as canary grass and Canadian thistle.
The plan is to expand that two-acre success into Fernhills big 90-acre South Wetland.
When the renovated area is in full swing, CWS Forest Grove treatment facility should be able to discharge treated wastewater into the Tualatin River year round.
Currently, it can do so only during the colder months because high summer temperatures cant cool the wastewater, much of which has been heated by humans for a variety of uses, said John Dummer (pronounced Doomer), principal engineer for CWS Watershed Management Department.
If emptied into the Tualatin, that warmer water could create oxygen-sucking algae blooms and other problems that would hurt salmon and steelhead, Kinnear said.
So for about half the year the hot half Forest Grove and Cornelius wastewater gets pumped from Forest Grove through a 17-mile pipe to CWS much larger Rock Creek Treatment Plant for processing.
But Fernhills renovated wetland should eventually provide enough plant cover to shade and cool treated wastewater, even in summer.
While the renovation is pricey, its far less expensive than the alternative expanding the Rock Creek treatment plant. That would have cost $31 million, said Diane Taniguchi-Dennis, deputy general manager for CWS, while the wetland project costs only $18 million.
Billions of seeds
The big 90-acre South Wetland will be more wildlife-focused than the Lower Treatment Wetland and the Water Garden just to the north. To help mark the border between the people area and the bird area, the city of Forest Grove will donate a couple of giant cedar logs from its watershed so they can be aesthetically placed between the two areas.
Public paths will circle around the South Wetland pretty much as before, though with more aesthetic curves to improve the walking experience. As before, no dogs will be allowed.
Originally, the South Wetland was made of one 50-acre lagoon called Fernhill Lake and two 20-acre lagoons called Cattail Marsh and Eagles Perch Pond. Built in 1964, the lagoons stopped being used for sewage years ago, Wantland said.
Under the new design, there will be only one 21-acre open pond, on the east side of the Fernhill Lake area. The other 70 acres will be emergent wetlands with pockets of open water dotting a patchwork of sedges, rushes and Bur reed all plants that help remove pollutants from wastewater.
More than 3 billion seeds have been planted, Kinnear said, using a hydroseed concoction that includes fertilizer, mulch and a tackifier (basically superglue) to keep the seeds stuck to the ground where they fall. Otherwise, theyd float to the top of the water when it starts raining and the wind would blow them towards shore en masse.
Another 750,000 partially grown species have also been planted in the area, Kinnear said.
Dreams coming true
The designers spoke with local birders and members of Portland Audubon to get ideas for the site.
One of the things they loved is when we lowered the ponds, the shorebirds showed up, said Taniguchi-Dennis. So we actually created some habitat for shorebirds.
They said If you guys could give us 500 square feet wed be happy, Kinnear remembers. CWS multiplied that request by 200, devoting about three acres (roughly 100,000 square feet) of mudflats on the southeast side of the pond, hoping a variety of long-legged, long-beaked sandpipers will flock to the shore.
C&M Construction, which is handling the renovation, inserted about 225 old logs into the 90-acre footprint. About half the snags will stand upright to attract flickers, wood ducks and other cavity-dwelling birds. The rest will be more horizontal or slanted, to be used by turtles, ducks and other species.
To help keep track of the number and diversity of species that come to the new wetland, Portland Audubon will begin doing bird counts in mid-November, Kinnear said.
There will be no stocking the pond with fish, reptiles or amphibians, said Dummer, the project manager. But the heavy flooding that usually occurs during winter should allow such critters to enter the area from adjacent wetlands, as well as the nearby Tualatin River and Gales Creek.
Pretty much amphibians and microinvertebrates will come in naturally, Dummer said.
We took the Field of Dreams approach, Kinnear said. If you build it, they will come.JW_DISQUS_ADD_A_COMMENT