Small rain gardens can have big impact on lake
MIDDLEBURY — “People keep stopping us and asking questions,” said Lauren Slayton and Justin Willis, the two landscapers planting out the new rain garden in the Riverfront Park at the Marble Works in Middlebury early this month.
Straight down the bank from the park, Otter Creek rushes toward Lake Champlain. Every grain of soil and every drop of water that runs off the Marble Works parking lots and rooftops and into the river contributes its own very small part to the very large problem of Lake Champlain’s phosphorus pollution.
“Basically, during a rain event, the entire south parking lot used to sheet across the park and go directly into the river,” said Ryan Emilio, of the Marble Works Partnership.
This one small spot shows in miniature why Lake Champlain cleanup requires all hands on deck for all Vermonters and how simple looking things like rain gardens can be important parts of the solution.
Emilio said that only about half to a third of the runoff from the south lot drains into the existing rain garden. So the Marble Works Partnership wanted to create a new rain garden to catch the rest. Last year they rebuilt the curb along the south end of the south parking lot so that it would better funnel stormwater into the rain gardens area. At the end of October and beginning of November, they installed the new garden itself.
“We’re responsible for the environment just as well as everybody else is, and that’s a big parking lot,” said Emilio. “We’re just trying to do our part.”
A rain garden is a depression — this one was clawed out by a small backhoe — planted to catch and filter stormwater. In 2013, the first rain garden was installed at the Marble Works in a partnership amongst the Marble Works Partnership, the town of Middlebury, the Otter Creek Natural Resources Conservation District and the Let It Rain program, with some public donations. It was designed by LandWorks landscape architects, which has offices in the Marble Works, and installed by volunteers.
The new rain garden is being installed by the Marble Works Partnership alone. Slayton and Willis, the duo hired to do the actual planting, are tweaking the original LandWorks planting list, adding some of their own favorites, along with plants suggested by Greenhaven Gardens and Nursery.
Like the Marble Works complex, many of the towns throughout Addison County are built along rivers, which rush down off the western slope of the Green Mountains. Steepness and proximity combine to rush pollutants and eroded soil particles, with phosphorus ions attached, directly into rivers and on into the lake, explained Kevin Behm, assistant director of the Addison County Regional Planning Commission.
In Addison County, certainly, runoff from towns and other developed areas doesn’t usually have far to go to meet a conduit to the lake.
Not only that but the rugged Green Mountains that define so much of the state also mean that Lake Champlain has what experts call a high “watershed ratio” of 18-to-1. According to the Lake Champlain Basin Program’s “State of the Lake” report, “For every square mile of lake area, there are 18 square miles of land area in the watershed that drain into the lake.” By way of comparison, the “watershed ratio” for the Great Lakes ranges from just 1.5 to 1 to 3.4 to 1. That means, as the report further explains, that “acre for acre, the watersheds of those lakes have a much smaller impact on their water quality.”
So in Vermont every square mile that drains into the lake has an impact on the lake, and remediation of drainage problems from every square mile also has a great impact.
“This is a long-term problem, a long-term solution,” said Jim Pease, a specialist in the development of municipal stormwater management programs for the state’s Department of Environmental Conservation.
Pease stresses that thinking about stormwater runoff isn’t just something that towns need to do; it’s the responsibility of every Vermonter in the Lake Champlain watershed. After all, the EPA has ordered Vermont to reduce phosphorus pollution from streets, roofs and back roads by 22.2 percent in the Otter Creek watershed.
According to Pease, even simple things like rain barrels or channeling your driveway or gutter runoff into your own lawn or garden or even taking your gutters down entirely can make a big difference.
“People make fun of rain barrels because they only hold, what, 55 gallons,” said Pease. “But if you multiply that out by thousands it would be a substantial amount of water” kept out of the lake.
“If it’s a 22 percent reduction, that’s a lot of developed land that has to be better at managing its runoff,” Pease continued. “It’s a very difficult problem because you’re dealing with thousands of properties and many, many sources of pollution. It’s not like the old problem of, well, we have a factory or a pipe or a wastewater plant or whatever it is, and we just have to get that fixed. We’ve got to find a Vermont solution.”
For more on how rain gardens can benefit Lake Champlain, see the related article, “Gardens change the face of a community” and “Asphalt is out, greenspace is in.” Reporter Gaen Murphree is at [email protected].