SAAWA learns how to reduce stormwater from homes

Speaker discusses driveways, lawns, roofs

By Elaine Ezerins

Staff Writer

The Facts

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ST. ALBANS — Homeowners can help reduce the impact of stormwater runoff on Lake Champlain’s water quality by making their property stormwater neutral, said Becky Tharp of Lake Champlain Sea Grant at the annual St. Albans Area Watershed Association (SAAWA) meeting Thursday night down by the Bay.

Tharp, the guest speaker of the night, heads an organization called the Green Infrastructure Collaborative (GIC), which is a partnership between the Agency of Natural Resources’ Department of Environmental Conservation and Lake Champlain Sea Grant at the University of Vermont (UVM).

GIC promotes low impact development and green stormwater infrastructure in Vermont watersheds to manage stormwater runoff from developed lands.

For her presentation, Tharp said every person can do their part to help improve the water quality of Lake Champlain and its surrounding waterways, not just farmers or wastewater treatment facilities.

When deciding what to speak about, Tharp jokingly said she was told by SAAWA that nobody wanted to hear about rain barrels because they weren’t going to make a difference in the grand scheme of things.

“To a certain extent, I understand we’re not going to save Lake Champlain by putting in a rain barrel,” Tharp said, “but I also think there’s a rule for everybody to sort of look really carefully at their own property… You have complete jurisdiction over it and you can decide where your roof runoff goes.”

Tharp gave some tips on how to take action on small sites such as single homesteads. For residential lawns, she advised the crowd to let their grass grow longer than three inches because studies show the extra length boosts the quality of the turf and increases the depth of the roots upping infiltration rates.

Infiltration is a natural process by which water enters into and through soil and other porous materials. According to the Vermont Green Infrastructure Initiative, it assists in the management of stormwater by removing sediments and pollutants, decreasing peak flows, recharging groundwater and delaying the transport of stormwater to nearby waterways, therefore reducing flash flooding.

Another green infrastructure practice homeowners can implement in their yards is replacing part or all of their lawn with native trees and shrubs, Tharp said. These plants have deeper root systems and absorb a lot more water, allowing for higher amounts of evapotranspiration.

A part of the water cycle, evapotranspiration is when the water evaporates from the earth’s surface into the atmosphere. Trees and other plants absorb the water through their roots and transfer it up to the atmosphere through their leaf pores. It’s a critical part of the water cycle because it represents a considerable loss of water from a watershed, according to the Green Infrastructure Collaborative.

Tharp also suggested homeowners aerate their lawns on an annual basis to increase infiltration rates and always test the phosphorus levels of their lawns before adding any fertilizer. For growing grass, the phosphorus levels tend to be “perfectly fine” in the Lake Champlain watershed, she said.

When managing stormwater runoff from the roof, homeowners should think about making their property stormwater neutral, which essentially means not exporting any stormwater runoff from the property. This can be done in a number of ways, Tharp said, including installing a rain barrel, rain garden or other green infrastructure set up.

With a rain barrel, the water runoff collected from the roof can be used during a dry period. “This year, we’ve had quite a lot of long dry periods and we’re seeing an increase in interest in using cisterns in Vermont,” Tharp said, describing them as larger rain barrels that can be buried with a pump attached.

Tharp said it doesn’t matter which type of green infrastructure the homeowner decides to go with, its just important to keep the water from running off the roof onto the driveway and flowing into the street where it will fall into catch basins because those ultimately empty into Lake Champlain.

When water runs off developed lands into storm drains, it picks up hydrocarbons, animal feces, trash, debris, phosphorus, and salt, among other things, along the way, Tharp said.

She said dirt driveways needed to be treated the same as dirt roads because research out of UVM shows their phosphorus loading to be nearly as significant. Directing water off dirt driveways into the soil adjacent to the driveway instead of the main road can be accomplished by installing infiltration trenches along the side or by lowering the surface of the ground on either side of the driveway.

Tharp also advised owners of properties along the shore to become Lakewise certified, which essentially states that the property is in compliance with The Vermont Shoreland Act. Passed in 2014, the act established state regulations for guiding development within a protected shoreland area, which is the area 250 feet from the mean water level of all lakes greater than 10 acres in size.

For more information about green stormwater infrastructure and the collaborative, visit