From The Blog

The Marsh is a Critical Barrier to Protect Our Island from Flooding; Let’s Keep it Healthy

Kiawah’s marsh is the frontline to protect our barrier island from storm surges and extreme tidal events, so maintaining its health is imperative. Its grasses, oyster beds, and mudflats act as natural buffers, moderating high-water events. One way to protect the vitality of the marsh is through increasing pervious surfaces on Kiawah, which reduces the impacts of stormwater. This would include converting parking lots, driveways, patios, and walking paths from asphalt and concrete to pervious materials like pavers and crushed aggregate.

When stormwater runs off of impervious surfaces, it collects pollutants, which are carried into storm drains. Kiawah’s drainage system has several outfalls, all of which empty into the Kiawah River and the marshland. If water can immediately penetrate the ground instead of entering storm drains, pollutants are filtered out in the soil before reaching the aquifer, and the groundwater benefits from replenishment.

Another threat to marsh health is erosion from stormwater runoff. A sudden influx of stormwater channeled into rivers and streams from pervious surfaces in the drainage system is known to cause erosion and flash flooding events. If water can penetrate the ground, it reduces the quantity of water in storm drains that can detrimentally impact the marsh.

In addition to protecting the marsh, pervious surfaces can help protect the value of your home by reducing your property’s flood risk. If your driveway, patio, or walkway requires replacement, or if you’re building a new home, consider utilizing pervious surfaces on your property.

You may also find cost savings if your neighbors join in on a similar replacement project. The aging Oceanwoods neighborhood, recently harnessed group negotiating power to reduce the cost of replacing 60 driveways with pervious pavers by 50 percent. The regime garnered group discounts from the material and installation provider, the surveyor, and the ARB.

The Town of Kiawah Island’s Marsh Management Workgroup is spearheading an effort to expand education about the benefits of pervious surfaces. The group, comprised of representatives from several island entities and community members, is putting together a resource guide of ARB-approved pervious materials, like the Belgard Pavers that the Oceanwood neighborhood used, and will be hosting a series of lunch-and-learn events for local design and building professionals. In addition to pervious pavers, the ARB may currently approve other pervious options like dark gravel or pervious concrete. Meanwhile, the group is developing a map of Kiawah’s surfaces to determine its pervious to impervious surface ratio. This can be analyzed to determine optimal areas for impervious to pervious conversion, and will also serve as a tracking tool to monitor how the ratio changes over time, and how it impacts flood events.

To follow along with the meaningful work of the Marsh Management Workgroup visit the town’s website at kiawahisland.org/marsh.