Rain Gardening in the Lowcountry!

 

The Seabrook Island Garden Club’s March meeting was entitled Rain Gardening in the Lowcountry! and featured guest speakers Lee Bundrick and Sean Cannon from the Kiawah Conservancy. Given the increasing concern about flooding caused by stormwater runoff, communities and individuals are interested in exploring what can be done to mitigate flooding in low-lying areas. Rain gardens are a simple nature-based strategy that can be implemented to help address flooding.

 

Lee Bundrick began with an explanation of the “science” behind rain gardens. Since rainwater is the primary source of freshwater in coastal areas, the Conservancy and the College of Charleston initiated a groundwater monitoring program on Kiawah Island to assess changes in the water table caused by rising tides and more frequent flooding events. While most of the rainwater on the island is captured by the forest and vegetation, the water table is relatively shallow (2-3 feet) and can only hold a limited amount of water. If rainwater cannot infiltrate the ground quickly enough, it begins to run off or pool in certain areas. As an increasing number of impervious surfaces such as houses, roads, driveways, and sidewalks take over previously forested areas, water pooling and flooding become more problematic. Unfortunately, this runoff water often contains pesticides, plastics, fertilizers, petroleum-based particulates, etc. These contaminants end up in the local waterways and can impact the wildlife and local ecosystems. One mitigation effort that grew out of this study was a recommendation to educate local communities and residents on the benefits of establishing rain gardens to mitigate flooding.

 Sean Cannon’s role with the Conservancy is to help communities and individuals design and implement rain gardens. He offered the following instructions on how to establish a rain garden on your property.

 1. At its core, a rain garden collects rainwater, holds it for a limited amount of time, and filters it before slowly releasing the water into the ground. The first step is to determine where water pools on your property. This is often a dip or depression in a low-lying area of the yard. Rain gardens, however, should not be placed in areas where water pools but should be located upslope of such an area to capture the water and eliminate the pooling.

2.    Rain gardens should not be placed too close to foundations since they do collect and hold moisture. Ideally, a rain garden should be at least 10 feet away from any type of structure on your property.

3.    It is important to amend the soil in the area using two parts sand and one part topsoil to maximize drainage. The rain garden should be at least 12-24 inches in depth with a 3-4 inch topping of cedar mulch.

4.    Ideally, the garden should be planted with native plant species. Some examples include river oats, scarlet sage, beautyberry, canna lilies, blue flag iris, and cardinal flowers. Plants should be drought-resistant but able to tolerate damp conditions for extended periods.

5.    Once established, rain gardens are relatively low-maintenance areas. They require weeding but generally do not require irrigation.

The Kiawah Conservancy staff members are willing to help communities and individuals design and establish local rain gardens. Most designs are very simple. The key is finding plants that will thrive in your area. Please feel free to contact Lee and Sean for assistance.

 

M. Lee Bundrick is the Senior Ecological Health and Conservation Coordinator for the Kiawah Conservancy and has been working on Kiawah Island since 2019. He holds a Bachelor of Science in Horticulture from Clemson University, a Master of Science in Environmental Studies from the College of Charleston, and a Master in Public Administration from the College of Charleston.  He works primarily in the areas of land protection, land stewardship, and environmental research, with a focus on the Kiawah River Watershed region covering Kiawah, Seabrook, and Johns Islands. He is a Certified Master Rain Gardener and is also an Adjunct Professor at the College of Charleston where he currently teaches the introduction to environmental and sustainability studies for the graduate school. Lee’s contact information is: lee@kiawahconservancy.org.

Sean Cannon is the Restoration and Enhancement Specialist for the Kiawah Conservancy. He earned a Bachelor's of Science in Business Administration from the University of South Carolina and a Master's of Science in Environmental Studies from the College of Charleston. Sean focuses on the implementation of Nature Based Solutions, habitat restoration, and community outreach and education. He is a Certified Master Rain Gardener and received a letter of Completion in Stormwater Pond Management through Clemson Cooperative Extension. Sean’s contact information is: sean@kiawahconservancy.org.