Winter 2007

stormwater
photography by Andy Duback

A flood of knowledge
Seeking better ways with stormwater

Alexey Voinov holds a glass over his desk. “If you pour it on a sponge, all your water will soak in and then evaporate or slowly trickle out,” he says. Then he runs his hand across the smooth desktop. “Or, if you spill on this table, it will flow down onto the floor with a big splash.”

“When we build conventional developments and houses,” continues the research associate professor in the Gund Institute for Ecological Economics, and one of five UVM faculty working on a research program called Redesigning the American Neighborhood, “we are replacing our sponge—which is soil, plus vegetation, plus subsurface flows—with a desktop—which is pavement. When a storm comes, imagine what happens.”

To see what happens, on a rainy day, head south from Burlington on Route 116 and turn at the sign for Butler Farms. Here, on former pastureland, 258 big houses on third-of-an-acre lots form the quintessential American subdivision. Strung along immaculate curving streets, the houses look out on close-cropped lawns, driveways that park four or five cars, and a wide roadway bordered by concrete curbs and frequent storm drains. As the rain pounds down on a gray November afternoon, oily eddies form over each drain, collecting water into pipes beneath the street and dumping into a ditch that runs through the center of the subdivision.

Or at least it looks like a ditch. This modest stream, overhung with dead goldenrod and stitched together with metal culverts, is actually Tributary Seven of Potash Brook. In two hours of heavy rain, it becomes a swollen rush, receiving from Butler Farms and adjacent Oak Creek Village more than a million gallons of water—carrying sediment, Turtle Wax, engine oil, lawn fertilizer, and Fido’s most recent deposit—on a non-stop trip to Lake Champlain.

A microcosm of countless neighborhoods, streams, and lakes throughout the nation, this South Burlington watershed is one focus of investigation by the Redesigning the American Neighborhood Program. With support from Sen. James Jeffords, the multi-year effort has been funded by the Environmental Protection Agency and brings UVM researchers (primarily from the Rubenstein School for Environment and Natural Resources and the Gund Institute) together with numerous partners outside the University to ask the question: How can we better manage stormwater in urbanizing landscapes?

Answers at Every Scale
Dig a detention pond is the traditional answer. And this neighborhood, under pressure from tightening state regulations, might do just that. “But that’s not their only choice,” says Breck Bowden, the Patrick Chair in Watershed Science and Planning and the lead investigator in the program. “And it may not be the best choice. We want folks to be aware that there are alternatives to big-scale engineering.”

One of them is growing near the corner of Moss Glen and Mill Pond lanes. Here, in front of a tidy red house owned by Anita and Russ Shapiro, a tiny wall of stones borders a garden. It seems an unlikely bit of stormwater engineering. But, as water flows off the roof, it doesn’t run out into the street. Instead it drains into this  “rain garden,” a gentle depression in the yard that pools water behind the stones and, over a few days, lets it percolate back into the compost-rich soil or get soaked up by a selection of water-tolerant plants, like black-eyed susans. 

One of two such demonstration gardens built in this neighborhood by one of the program’s partners, Jessica Andreoletti of the Winooski Natural Resources Conservation District, it is an example of what these researchers call “green” or “distributed” stormwater systems that are built at a household or neighborhood level and try to mimic natural patterns of water flow.

Of course, a few rain gardens will not handle all the stormwater in Butler Farms. But if they were built at every house, in combination with other improvements—“we could bring this neighborhood’s impact on Potash Brook way down,” Bowden says. “And that would be good for more than just the stream. Anyone who drinks water, swims, boats, fishes, or pays taxes should care about this.”

“The heart of the stormwater question is realizing that every watershed has numerous options for intervention—at several scales,” he says.

At a household scale, simple interventions, like rain barrels under downspouts and strips of native vegetation between the brook and lawn, are attractive low-cost options, while cisterns and “soakaway pits” built under lawns and driveways have proven effective in other cities. “And if people behave differently, that’s a form of stormwater treatment,” Bowden notes. Cleaning up after the family pet, letting already-rich lawns take a fertilizer break, developing a designated car-wash site in the neighborhood, planting trees—all help.

And what about permeable pavement, replacing curbs with grass berms, or making the roads narrower? These, and other options, are described as part of a decision-aid “toolbox” on the program’s website (uvm.edu/~ran) that the UVM researchers have developed for planners in other communities to use. At a larger scale, existing swales in the development could be converted to handle stormwater or a nearby wetland could be engineered to absorb pollution.

One of the researchers in the program, John Todd, is a world-renowned innovator in ecological design. If there was a will to do so, he and his colleagues are confident that neighborhoods like this one can be greatly improved, and new developments—like the proposed “Marceau Meadows” subdivision now seeking a stormwater permit for construction on a hundred acres above Butler Farms—could be designed to have almost no stormwater impact.

Stormwater

A Daunting Problem
“But whatever intervention the neighborhood chooses requires an investment, and most folks don’t realize that stormwater is their problem or even a problem at all,” Bowden says. “So we’re creating a dialogue.”

It’s a dialogue driven by a $2 million price tag. The homeowners in Butler Farms and Oak Creek Village face a daunting problem: Their 1980s’ stormwater discharge permits are long expired, their little tributary is part of a larger EPA “impaired” stream, and they have an October 2007 deadline to renew their two permits.

Their existing stormwater management system, two elderly detention ponds at Oak Creek, is not much use. Working well, detention ponds do a reasonable job protecting downstream waters, but they need to be dredged and their pipes cleared. These two have been neglected for years. Now they are choked with sediment.

So with support from the UVM team, officials from South Burlington, and Jack Myers, a consulting engineer from Stantec Inc., the neighborhood has formed an unofficial “stormwater working group.” Drawing on the Redesigning the American Neighborhood Program’s rigorous studies of the clay soils and water flow in the area, insights from a neighborhood survey, and several “watershed field days” and other gatherings, the group is now considering several proposals for new stormwater systems. 

The researchers’ goal: Assist the neighborhood with these stormwater choices, while developing an understanding of what approaches are going to work here, not just ecologically but socially. The neighbors’ goal: Pass muster with Vermont’s Agency of Natural Resources and renew their permits.

Distributed systems, like rain gardens, are better for water quality and a natural water cycle than the “old paradigm of drain it, pond it, get rid of it,” says Jim Pease ’79, with the Agency of Natural Resources. But they’re less well-studied, require individual maintenance, and might be costly and disruptive in the short run. No final decision has been made (and even how this decision will be made, considering there is not a formal homeowner’s association, remains cloudy) but Myers’ engineering studies suggest that a modern version of the old-fashioned detention pond appears to be the cheapest, easiest option for getting a permit. For many homeowners who already feel blindsided by having to foot the bill for a stormwater fix, that’s what counts.

If they choose the updated detention pond, the system will start with a small “forebay” that will catch the initial surge of sediment, branches, and garbage and could be dredged on a regular basis. From there, water would flow down to a larger pool that catches most of the volume from a storm. This pool also helps moderate water temperatures, helpful to cold-loving fish downstream, and exposes the water to UV light from the sun that helps kill unwanted bacteria. This system, Myers calculates, will cost $2.3 million. Barring help from the city or the state legislature, this means about five thousand dollars per household.

“I don’t even understand why our neighborhood has to pay for it,” says Anita Shapiro. “The guy who developed this place should be liable.” But the developer is long gone.
“We could do something with that five thousand dollars,” her husband says. “It doesn’t seem fair; we already have wicked taxes.”

Fair or not, the effect of a 1997 Vermont Supreme Court ruling is that violations of land-use regulations are a “cloud” on a person’s property title. In other words, the Shapiros are part of a group of three thousand homeowners in South Burlington, and a scattering of others across Vermont, who face the specter that they might have difficulty selling their property until they can renew their stormwater permit.

But getting a permit may get harder. As the federal government has moved into a next phase of enforcing the Clean Water Act—and diffuse sources of pollution, like stormwater, have become the leading cause of water contamination nationwide—the EPA has ordered every state to develop plans to restore their most damaged waters. Vermont’s stormwater laws have provoked a swirl of legal fights and new rules, but the upshot in the state’s seventeen “impaired” waterways, like Potash Brook, is that, starting next year, stormwater permits will be granted based on tougher, more scientific measures of water pollution and health.

If this regulatory pressure is the stick, then South Burlington’s new stormwater utility is the carrot. Just like a monthly fee for trash collection, the city’s utility charges homeowners $4.50 per month to maintain their stormwater systems, from drains to ponds. This innovative approach is the first such effort in Vermont, and people in Butler Farms and Oak Creek want in: Once they are part of the utility, their headache is done, since the city takes over the permit and  manages the stormwater system. But the utility won’t let them join—until they have a workable stormwater management plan.

A Trip Down Tributary Seven
So why, exactly, does the American neighborhood need redesigning in terms of stormwater? What’s so wrong with having rain just dump into a ditch? A trip down Potash Brook tells the story.

Tributary Seven begins in a wet meadow at the south end of Butler Farms. At this headwater, Bowden and graduate student Alexander Hackman set up probes that measure both the quantity and quality of water during storms. Usually, the volume here is low, and the water is pretty clean.

The same measurements taken on the downstream side of the development look a lot different. As rainwater moves across impervious rooftops, asphalt, and compacted lawns, it picks up an unhealthy brew of sediment and chemicals. The data these researchers collected over two field seasons show that during storms, loads of sediment more than double and phosphorus increases by 40 percent between the two monitoring stations.
And, instead of a gradual build-up of stream volume as would happen in a natural watershed, “the brook goes from a little trickle to a biblical flood in ten minutes,” says Hackman. In a very big storm, they calculate, more than three hundred tons would run off this neighborhood. That amount of water does roughly the same damage as driving a bulldozer up and down the streambed for the better part of an afternoon.

This sudden blast—that hydrologists call storm surge—continues downstream, and joining dozens of similar flows, dumps into the mainstem of Potash Brook, scouring out phosphorus-laden soil from the streambank all the way to the lake. In this cloudy, dirty rush of water, few varieties of insects or native fish can survive. And the ongoing accumulation of phosphorus in the lake is a big problem. Beach closings, algal blooms, poor fishing, and a host of other ills on the lake cannot all be blamed on industrial outpipes or cows standing in streams. Stormwater is now the leading cause of water pollution in Burlington Bay.

Enlisting the Community
But it’s not easy to see. “You can come up with the best water treatment technology in the world,” says one of the program’s partners, Juli Beth Hinds, looking down at a spaghetti-pile of culverts coming out from under Butler Drive, “but if people don’t understand why they should use it, or pay for it, or if they feel cut out of the process, they aren’t going to support it.” As South Burlington’s planning director, Hinds is on the frontline of what she calls Vermont’s “stormwater permit wars,” and she welcomes the combination of scientific expertise and community education skills the UVM team has assembled.

“This is an affluent, professional neighborhood with a lot of civic activity,” Hinds says, “but there are not many people here who would spend their weekend doing streambank restoration.” The UVM program’s survey showed that only half of the residents realize that stormwater ends up in Lake Champlain (not in a treatment plant) and more than 65 percent use lawn fertilizer, one of the culprits in water pollution. These statistics hint at what might be the biggest challenge—and lesson—these researchers have uncovered: There is little understanding of stormwater, and cleaning it up, like many environmental problems, is perceived as somebody else’s job.

But not every resident sees it this way. As Bill Craig ’67, a member of the neighborhood’s stormwater working group, notes, “We’re all responsible, so each neighborhood should do its part. It’s a big effort, sure, but we’re going to have bite the bullet or kiss the lake goodbye.”

Adding to the challenge, the science of stream recovery is in its infancy. Alan McIntosh, Bowden’s co-leader on the program and an expert on stream biology, notes, “managing stormwater is the worst of two worlds. It’s very high in scientific uncertainty, and it’s very expensive. We don’t yet understand enough about how stream organisms are responding to a combination of pollutants and stresses to be able to confidently say ‘here is what you have to control to bring back mayflies and fish.’”

And what Evan Fitzgerald discovered isn’t encouraging. One of a group of graduate students conducting research through the Redesigning the American Neighborhood Program, he has been studying what happens to “all the bugs in the stream,” he says, as a natural watershed becomes developed. Fitzgerald notes that when an area is very lightly developed, its water remains in “good biophysical health, but there’s a threshold.” As more houses and roads are built, like what much of South Burlington has already experienced, many sensitive species just aren’t found. “The take- home message,” he says, “is that, above 5 percent impervious cover, we don’t see any stream conditions that are good; they’re fair at best or poor.”

The hurdles Hinds, McIntosh, and Fitzgerald describe are exactly why the Redesigning the American Neighborhood Program sees “shared learning” as its core work and doesn’t have a one-size-fits-all-watersheds answer. There is still much to learn from research on Potash Brook and from comparing it to other federally “impaired” and pristine streams nearby. “And part of our research is simply listening to homeowners, planners, developers, and policymakers—trying to understand what science is going to be most useful,” Breck Bowden says. Whatever intervention is finally put into place at Butler Farms can be evaluated over time using data from the program’s monitoring stations as a baseline of change and improvement.

“We’ve spent two hundred years putting ourselves in this situation: we’ve got to expect that it will take us more than five or even ten years to fix those problems,” Bowden says. But he is optimistic. “We have engineered people going to the moon and built the Aswan High Dam,” he says. “We can put our minds to problems close to home like stormwater pollution and solve them.”

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