Since 2015, our community has experienced a number of named storms and major flood events, causing many residents to question how to best manage water in the home landscape. The following are considerations for addressing flood- and erosion-prone areas in your yard.
Treat your property like a small watershed. Next time it rains, grab your umbrella and step outside to observe. Note the source and the destination of stormwater runoff during rainy weather. The source may be an area of impervious surface, such as a rooftop or driveway, where rainfall is unable to infiltrate. The destination may be a ditch, storm drain, backyard creek, stormwater pond, adjacent property, or even a low spot in your yard. When considering how to manage water, knowing the path water travels from source to destination is helpful in identifying management strategies.
Incorporating landscape beds into lawns can help manage water. Plants native to our region, including perennials, grasses and shrubs, typically have deeper roots than a traditional turf grass. This deeper root system will allow water the opportunity to infiltrate, or soak, into the ground. Once established, native plants often require little to no irrigation, as these plants are adapted to Lowcountry conditions. Avoiding excessive irrigation helps to ensure soil is not saturated, which will help with infiltration the next time it rains.
If your yard experiences periods of saltwater inundation during high tides or storms, consider using salt-tolerant plants. The Carolina Yards plant database can help with plant selection at Clemson.edu/cy/plants or visit Clemson’s HGIC factsheet 1730 and 1856 at Clemson.edu/hgic for additional information.
Establishing or protecting trees on personal property can help manage water. All the way from the leaf canopy to the roots, trees are nature’s heavy lifters in managing stormwater. Through the processes of interception and transpiration, as well promoting infiltration, a mature tree can handle up to hundreds of gallons of water during a single rain event. Research had shown that the canopy of a live oak tree can intercept upward of 30 percent of rainfall before it hits the ground.
Where possible, avoid soil compaction. When vehicles and other heavy machinery are driven or parked on turf grass and other landscaped areas, these areas become increasingly compacted. Once compacted, an area that functioned as a pervious surface can become an impervious one.
When installing a patio, walkway or driveway, consider using a diverse array of materials, including interlocking pavers, gravel grid systems and even permeable asphalt or porous concrete. These surfaces have improved porosity over traditional paver systems, allowing water to soak back into the ground. If you are on a budget, another pervious or semi-pervious option is creating walkways using stepping stones or mulch paths.
Rain gardens and rainwater-harvesting systems are becoming increasingly popular. These features assist in returning the site to pre-development hydrology, reducing the volume of runoff generated by allowing water the opportunity to slow down and infiltrate. Rainwater is managed on-site, thus reducing the strain on our storm drainage system, which is designed to manage flooding in the community. A rainwater harvesting system captures and stores water flowing off of the roof; this water is later used for irrigation or other nonpotable water uses. A rain garden is really a misnomer, as this landscaped depression is more often dry than wet. Rain gardens are designed to encourage infiltration.
If you want to learn rain garden and rainwater-harvesting system design, register for Clemson’s Master Rain Gardener course, now open at Clemson.edu/raingarden.
As you have identified the destination of water leaving your yard, make sure to keep runoff conveyance areas clear. Remove accumulated yard debris and litter from your ditches and drains before and after storms. When doing lawn work, compost or bag yard debris for pickup. Call your local government if you notice a significant issue or maintenance need.
In extreme cases, consider installing a sump pump, French drain or other system that will physically move the water in your yard. Consult with a professional on the most appropriate options for you.
Lastly, stormwater runoff is untreated. Water that flows across the landscape into the street, storm drain, or ditch is being discharged into a nearby water body. The pollutants that are picked up along the way, such as excess fertilizers, pet waste, gasoline and litter, can wreak havoc on water quality in Lowcountry waterways.
These same waterways are the ones we depend on for recreation, food, our local economy and way of life. We all play a role in managing stormwater runoff for both water quantity and water quality.