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Environment | Water

New Center Tests Sustainable Stormwater Methods

PUYALLUP — Curtis Hinman looks skyward to a ceiling of clouds in Western Washington. It’s a mid-summer day that could break into either sunshine or showers.

Hinman is hoping for rain.

If it rains enough today, he will be able to take the first official readings at Washington State University’s Low Impact Development Research Program in Puyallup, a new, one-of-a-kind in the nation facility for testing sustainable stormwater management.

“We’re just getting started. We’re hoping to collect a water quality sample from a storm this afternoon,” said Hinman, the director of the program and co-designer of the facility.

The low-impact program is part of the Washington Stormwater Center, created under a 2009 mandate from the state legislature and funded through $1 million in grants from the Washington Department of Ecology. The University of Washington hosts a sister site in Tacoma.

Hinman’s work focuses on stormwater management projects, including rain gardens, rain harvesting cisterns and permeable pavement.

About half the Puyallup site looks like an ordinary parking lot but is covered with porous asphalt and pervious concrete instead of traditional blacktop. Water seeps into this alternative pavement rather than skimming across its surface. Researchers here are studying how much water percolates through these materials and how well the materials filter pollutants from stormwater.

The other half of the site is dedicated to what Hinman calls “bioretention research,” or the study of rain gardens. Rain gardens, which are shaped like a bowl and built to absorb and naturally purify runoff, were first developed in Maryland in the early 1990s and have been gaining in popularity across the United States. But research on how well rain gardens work has been mostly anecdotal. The stormwater center’s data will provide hard evidence about which plants thrive in rain gardens and which soils filter contaminants most effectively.

Each research station has monitoring equipment that will provide detailed information, which will eventually be published online in real time. Weather stations will monitor temperatures, rainfall, wind and relative humidity. Other sensors will collect runoff and flow data from the test pavements, rain gardens and cisterns.

“What’s really unique about this is that we built in all this research capability into a functioning stormwater facility,” Hinman said. “Replicated research is often done in a laboratory on a small scale. Here we have full-scale, replicated research. It’s unusual.”

This research is getting started just as cities and counties nationwide are in making a big shift away from conventional stormwater management, which whisks away rainwater through networks of pipes and sends it to nearby ponds or waterways.

“In the past, we’ve provided a drain and a way for water to get off the property. And as long as that water went down the drain, that’s all people needed to know,” Hinman said. “And probably all they cared about.”

But these stormwater management methods are causing one of the nation’s largest water pollution problems. When rain flows over nonabsorbent surfaces such as roofs and roads, it gathers whatever happens to be there. Roofing materials contain heavy metals like copper and zinc. Lawns can contain fertilizer and pesticides. Roads are covered with grit, grease and oil.

All those contaminants are carried into streams and estuaries. This form of pollution, called non-point source pollution, accounts for 85 percent water pollution in the United States, according to the Environmental Protection Agency.

About 75 percent of the pollutants found in Puget Sound are carried there by runoff, the Washington Department of Ecology reported in 2008.

Another part of the problem is that in many older neighborhoods, stormwater pipes and sewer pipes are often one and the same.

“We have these pipes that were built for the capacity 70 years ago, but we’ve built so much impervious surface since then,” said Anne Nelson, who works with the City of Portland’s Bureau of Environmental Services.

Nelson is leading a large-scale project to install more than 500 “green streets” in urban Portland. The green streets will replace impervious surfaces with rain gardens, eco roofs and permeable pavement that will filter and divert stormwater, ultimately relieving the sewer system.

With so much pressure on aging combined sewer-stormwater systems, it doesn’t take much rain to cause them to overflow. And when they do, a slurry of stormwater and untreated sewage empties directly into waterways.

“We’ve been building infrastructure this way for 100 years, connecting pipes and sending water to and from a centralized facility,” Hinman said. “Now we’re realizing that’s not such a good idea. And we need to start disconnecting.”

And soon that likely will be the rule in Washington state.

“The way we’ve done stormwater in the past hasn’t worked well and we need to make some shifts from conventional methods to more sustainable methods. The question is how far and how fast,” said Bill Moore, stormwater manager for the Washington Department of Ecology.

Ecology officials are drafting new stormwater management rules that will require the use of low-impact, or green, infrastructure, where it’s feasible. But what exactly does “where it’s feasible” mean?

“We now know how to build green roofs, but do you want to require every single family house to have a green roof? That’s a feasibility question,” Moore said.

An advisory group for the department has been working for the past two years to spell that out in the state’s new green infrastructure guidelines. The language for these rules will be released in October for public review and comment, and the department has until July 2012 to revise and adopt the new stormwater requirements.

“It’s a big transition. We’re one of the few regions in the United States now requiring low-impact development as the first choice for stormwater management,” Hinman said. “It’s one of the largest shifts in a long time in how the built environment, looks and works.”

For some the shift is exciting, but others have misgivings about stormwater changes.

“A lot of people who are pushing for these controls don’t realize, or are dismissing, the challenges to maintain them,” said Curt Crawford, who is a manager in King County’s Stormwater Services division. “My concern is that because we’re building on individual lots, and we’re expecting property owners to maintain them.”

Crawford has seen property owners give up on rain gardens and fill them in because they don’t like them or because contractors didn’t install them properly. But his biggest concern is that property owners may not want to maintain something that’s beneficial to the whole community but not necessarily a big benefit to their individual properties.

Crawford also worries about what all this means for the future.

“There’s a lot we don’t know about the long-term effects and durability of low-impact development,” Crawford said.

And that’s where the Stormwater Center’s research comes into play.

“Right now we don’t have many good answers for people on how to control pollution once it gets into the stormwater,” Moore said. “This research will help us be able to quantify how well these particular practices remove pollution from stormwater.”

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