In November 2007 the Winooski NRCD contracted the environmental engineering firm EcoSolutions to design and build a stormwater treatment system that would decrease runoff and pollution in the impaired Potash Brook watershed of South Burlington. A highly channelized tributary of Potash Brook runs through Farrell Park, a 23-acre recreational park. The park is managed by the City of South Burlington and includes two athletic fields, a small playground and 0.75 acres of gravel parking lot. Due to the lack of floodplain in the tributary, sediment from the Farrell Park gravel parking lot was exported directly to Potash Brook. EcoSolutions proposed an Advanced Wetland Stormwater Filter (AWSF), for treating stormwater runoff generated from Farrell Park.

The AWSF is comprised of four distinct components, which include:

1) an inlet distribution system;

2) an outlet collection system and water level control;

3) a filter media; and

4) the Advanced Flushing System. 

Flow through the wetland is horizontal. Influent stormwater is introduced at one end, on the bottom of the wetland and collected a the top of the opposite end. A series of manifolded infiltration chambers are installed at even intervals perpendicular to the flow on the bottom of the wetland to minimize short circuiting.  

Three different layers of stone are arranged within the wetland cell, with the largest on the bottom, and graded to pea stone on the top. The permanent water level is maintained just below the surface of the pea stone with an adjustable stand-pipe system. The AWSF has a unique flushing system that provides the opportunity to rejuvenate the wetland cell by allowing accumulated sediment to be safely flushed from the stone media. The flushing system enhances treatment and extends the life of the system. 

The AWSF is the first of its kind to incorporate a flushing system in the nation. However, standard gravel wetlands observed at the University of New Hampshire’s Stormwater Center have proven to be superior to the 9 other stormwater treatment systems studied by the Center. The Center found gravel wetlands to be effective at removing an average of 99% of the Total Suspended Solids

The Winooski NRCD wishes to express their gratitude to EcoSolutions, LLC and partners for their expertise and commitment, the City of South Burlington Stormwater Utility Crew for their in-kind donation of machinery and labor, and the Environmental Protection Agency for their financial support.

Avoid Cabin Fever… Become a District Volunteer

Lend a hand at the Conservation Plant Sale; assist with the Rain Barrel Community Project in area schools; seek out new urban conservation project sites; gain experience with writing grants and implementing environmental education lesson plans; or participate in community outreach events as a District representative.  Volunteering is a great way to promote sustainability in your watershed while engaging in local environmental issues and resolutions. 

To learn more about these volunteer opportunities visit our website,  www.vacd.org/winooski

Vermont Rain Garden Manual: Gardening to Absorb the Storm

Just in time for spring, Vermont’s own Rain Garden Manual is available for free to anyone who is interested in protecting our local rivers and lakes through gardening. This sixteen page, full color Manual includes step-by-step instructions on rain garden design and installation; five creative planting plans; information about curb-cut rain gardens (perfect for urban streetscapes); a rain garden plant list (including 150 plants suitable for Vermont rain gardens), and an explanation of how rain gardens are compatible with the Vermont Stormwater Management Manual. 

Starting April 1st, pick up a copy of the Manual at Elmore Roots Nursery (800-42-PLANT), Elmore, and Arcana Gardens & Greenhouse (802-899-5123), Jericho. These two local garden centers have demonstrated a commitment to protecting our local waterways by providing financial support and committing to carry rain garden specific plants and supplies.

This work is sponsored in part by: Lake Champlain Sea Grant, NOAA National Sea Grant College Program,  US DoC.; The Cooperative State Research, Education, and Extension Service, US Department of Agriculture, under Agreement No. 204-51130-03108; Environmental Protection Agency; Chittenden Bank