Raingarden and rainwater harvesting system nourishes James Island community garden
JAMES ISLAND — Medway Park and Community Garden on James Island has a new raingarden and rainwater harvesting system that will help people in the Riverland Terrace neighborhood supply fresh vegetables for themselves and a community food bank and keep toxins out of their local waterways, thanks in part to Clemson Master Rain Gardeners and architecture students.
The installation will also serve as inspiration for park visitors, according to Leslie Wade, community gardening coordinator for the Charleston Parks Conservancy.
“The raingarden and rainwater harvesting system here at Medway will show the neighborhood what they can do with harvested rainwater in their home landscapes and that it is possible to harvest rainwater and put it to use. The system will also take away some of the garden’s reliance on city water for watering the beds for irrigation,” Wade said.
The Charleston Parks Conservancy’s Community Gardening Program includes Medway Park and Community Garden, Elliotborough Park and Community Garden and Magnolia Park and Community Garden.
Medway has 61 garden beds for lease by members of the community and 12 larger garden beds devoted to growing produce for local food pantries. Medway also has a pavilion designed and constructed by a team of Clemson University architecture students.
Wade joined landscape professionals from 25 South Carolina cities and towns who designed and installed the Medway Garden systems as the field day exercise for Clemson Cooperative Extension’s Master Rain Gardener professional certification training.
“This field day has given me the technical skill to take the knowledge I gained in the online course and actually put it into action in other parks and residential spaces. We’ve learned site selection, plant material, sizing, soil amendment. It’s been a very comprehensive class,” Wade said.
Kim Counts Morganello, Clemson Extension water resources agent and Master Rain Gardener coordinator, said the Master Rain Gardener course is a response to growing demand from clients who want to convert the state’s abundant rainfall into landscape features that can water gardens, control erosion and moisture, and provide habitat for wildlife.
“More and more homeowners call our Extension offices with concerns about rainwater puddling on their property and moisture near their home foundations. There’s growing interest in raingardens and rainwater harvesting systems and in sustainable landscape design and incorporating green gardening practices,” Morganello said.
Morganello led a team of Clemson water and horticulture experts in designing the Master Rain Gardener hybrid certification course. The course includes a letter of completion track, which is online instruction intended for home gardeners, and a certification track, which also includes a field component and is intended for professionals. The Master Rain Gardener course was offered for the first time this spring. The Medway Garden field day was the culmination of the certification track.
Charleston County averages approximately 51 inches of rain per year and South Carolina averaged 49.8 inches of rainfall per year over a 30-year period from 1970 to 2000, ranking it 11th among the states, according to data from NOAA National Climatic Data Center. Much of that rainwater falls in torrents due to dramatic storm events, runs off impervious rooftops, driveways and streets, then rolls into rivers and streams, picking up an array of pollutants along the way.
“With raingardens, we’re able to slow that water down and give it an opportunity to infiltrate into the soil. In this way, we can use physical, chemical and biological processes to clean the water before it flows into waterways,” said Cal Sawyer, Water Resources Extension specialist and associate professor in Clemson’s agricultural sciences department.
Sawyer taught students how to perform a soil percolation test to determine the water absorption rate of the soil in preparation for creating the garden. It was no surprise that the percolation test water disappeared fast into James Island’s sandy soil.
The all-day installation included instruction in site selection, raingarden shape and design, soil amendment, plant selection, and site and soil assessment. Participants also had the opportunity to learn firsthand about rainwater harvesting system design.
The Medway Garden system will harvest and filter water running off the roof of a pavilion designed and constructed in 2017 by a team of Clemson University architecture students.
J.T. Pennington, who is earning his master’s in architecture at Clemson, was one of 12 architecture students who worked with the Charleston Park Conservancy to design the Medway Garden pavilion.
The students took their design cues from an analysis of the landscape and how the park was being used.
“The pavilion has a horizontal east-west orientation and the roof is pitched to flow rainwater into the cistern and shade the gardeners from the late day and evening sun. The pavilion also has tool lockers on the west side of the building to shade the lockers from the sun,” Pennington said.
Pennington said the 820-square-foot roof will shed approximately 510 gallons of water during a 1-inch rainfall and divert it to a 750-gallon cistern which will overflow into the 140-square-foot rain garden. The system has been designed to handle a 1-inch rainfall.
The pavilion also includes a vegetable wash table and is designed to be a Good Agricultural Practices (GAP) certified, FDA-approved facility where the harvested food can be rinsed and prepared immediately for distribution to food banks rather than being transported to a separate site.