The Corvallis Wastewater Treatment Plant produces an end result of clean water–but when pumped into the Willamette River, it still has the potential to kill fish, including endangered salmon. The problem isn’t pollution, but one of temperature: the wastewater is simply too hot.
To solve the problem, the Corvallis Public Works Department is planning to pump the water under the Willamette River to a constructed wetlands. Pipelines drilled under the riverbed would send some of the water across the river to irrigate OSU’s Trysting Tree Golf Course. Another 4,000 feet of pipe would lead to the Orleans Natural Area, which would be converted into an artificial wetlands where the wastewater would cool before entering the Willamette River.
“We are designing it so that it would be a community amenity, including walking paths, interpretive signage, and habitat for birds and wildlife–and it’ll be right in close proximity to the city,” said Utilities Division Manager Tom Penpraze of the Public Works Department. “We think it’ll be a good way to solve a regulatory requirement and create a community amenity at the same time.”
The proposed park–which would include about a mile of trails–has been compared to the Talking Water Gardens in Albany. The latter is an engineered wetlands complete with waterfalls and trails that cools Albany’s treated wastewater before release into the river.
However, the Corvallis project may not be all it’s talked up to be–not least because the Orleans Natural Area is currently slated for reestablishment as a native floodplain forest. Students, Boy Scouts, and other local groups–including the city at one point–have already planted an estimated 800 trees that wouldn’t survive the conversion.
The Corvallis Parks, Natural Areas, and Recreation Advisory Board has voted against the project, saying that it would prefer the city keep to the current Master Plan for Orleans. Detractors say that the area is too small to compare to Talking Water Gardens; the Department of Transportation has an easement for a future expansion of the Route 34 bypass that could eliminate a large portion of the park; the site has poor public access; significant flood current is likely to go through the site after a 20-year flood event of large or moderate size; part of the area (the fledgling town of Orleans, wiped out by a flood in 1861) is a protected site listed on Linn County’s Historic Register; and another site, the “Bean Field,” could be turned into a closer approximation of the Talking Water site for less than the cost of the Orleans project.
Additionally, the plan relies on unproven technology. Because the chosen site is too small to cool the water on the surface like Talking Water, an unproven method of pumping water into shallow groundwater would be implemented to cool it further.
A computer simulation performed by OSU for the Oregon Department of Environmental Quality was inconclusive–and the heat may have detrimental effects to the area beside the river known as the hyporheic zone. Talking Water Gardens does not release water directly into the river but has a diffuser, a pipe with nozzles buried on the river-bottom that spreads the treated water out over a large area. The Corvallis plan does not involve a diffuser; water is released directly into the hyporheic zone.
This makes some wonder if Corvallis will be paying for an experiment whose results may ultimately benefit the state more than the city.
No tax money would be involved in the project; citizens of Corvallis would ultimately foot the bill. Household utility bills would increase by several dollars a month for several years to finance the $15 million project.
Penpraze maintains that it’s what the community wants.
“We went through a two-year public process to look at a number of different alternatives to solving the temperature issue, and this was the alternative that the community said was most acceptable to them,” said Penpraze, who listed town meetings and an online survey among methods used to solicit input.
He added that reforestation of Orleans Natural Area probably isn’t in the cards.
“The issue is there’s no plan in place and no money; right now there’s a farmer that’s farming the field for a hay crop, so it’s hardly a natural area. We believe we could make it closer to a natural area than currently exists.”
In addition to cooling the water, plants in the constructed wetlands would help remove ammonia, nitrates, and other substances that adversely affect the health of the Willamette River–including some that are not yet regulated but could be in the future.
When it comes down to it, both sides seem well-intentioned. Public Works is trying to meet water quality standards, and environmentalists are concerned about losing a Natural Area. If the plan goes through, construction would begin in late 2013 or early 2014. Both the Urban Services Committee and the Corvallis Parks, Natural Areas, and Recreation Advisory Board next meet on Thursday, Sept. 20. For more information about the project or to provide comments or input, visit http://www.ci.corvallis.or.us/tmdl”www.ci.corvallis.or.us/tmdl
By Jen Matteis