How to Stop a Runaway Driveway

Our client in Rabun County has a fabulous lot on Lake Burton but not a lot of money to do all that is needed in terms of post construction landscaping. They’ve done things in bits and pieces such as planting trees and bushes, putting down sod, building a retaining wall. The driveway, though, was beyond them. Also, the house sits at the bottom of a hill. It has had issues – not serious ones, just enough to be worrisome – with water in the crawl space.

Several factors are at play:

  • The location of the house 
  • The loss of vegetation on the uphill side of the house due to construction 
  • The slope and condition of the driveway 

They came to us initially because the gravel, and hence the driveway, was sliding (washing) into the woods (Image 1). It looks awful. And, they were concerned about the drainage to and around the house. To help with both, we came up with a way to improve the situation with the sliding driveway and protect the home from the wash of water that comes down the hill.  

Driveway washing into sideyard
Image 1: Driveway? Parking lot? Pathway into the woods? No, it’s the driveway washing into the side yard. The house is down the drive to the right.

Did you know that Rabun County gets the highest amount of rainfall of any county in Georgia? So, dealing with drainage is especially important for a home on a lot with a steep grade. (Although, drainage for a house on a flat lot in a place of high rainfall is almost equally challenging… but that’s another story.) 

Why don’t they just pave the driveway?  

Here are some pros and cons. 

  • Economically, a paved drive is initially more expensive. However, if you use gravel, over time the rocks will slip this way and that, potentially leaving property owners to pay again and again to replace their lost driveway material. 
  • Aesthetically, a paved drive would provide a clean and tidy look to the property and secure the footprint of the driveway. 
  • Environmentally, it’s a trade-off. Driveways are conduits for water and runoff from sloped gravel typically carries a significant amount of sediment (Image 1 & 2). Paved driveways, though, collect pollutants, such as oil, that will drain directly into living areas of the property. Those same pollutants, on a gravel drive, soak into the gravel, filter through the soil, recharge the groundwater, and keep pollutants out of the lake. 
  • Managing rainfall on a paved drive is more complex and requires a greater capital investment. The water will unquestionably run faster and in greater volume (because the pavement is impermeable) down the hill than it will when falling on gravel. Managing that faster, higher volume of water involves an entire site plan and different infrastructure.
Image 2: Here’s the drive. Note the smooth (relative to gravel) surface from bottom to top, an unimpeded pathway for water to flow down – and a gentle slope to the right. You can see how the gravel was running off into the side yard.

Image 2 shows the driveway as we found it during the winter. You can see the steepness of the grade and how the drive is pretty much a smooth run from top to bottom. Despite its permeability, water coming down the driveway and through the woods had nowhere to go except to the house. Another issue for the drive was that it sloped toward the side yard. It is because of that slope that you can see how the gravel was sliding off into the woods. 

Our solution was to add two swales to the drive toward the top and regrade the driveway at the bottom to redirect runoff. We also restructured an existing trench to guide run-off more effectively. Image 3 illustrates the elements of a swale.  

Elements of a swale
Image 3: elements of a swale

What is a swale? provides an excellent definition of a swale. “A swale is a depression created in the ground that carries rainwater by gravity away from your home and property…. Therefore, a swale collects the water by being the lowest point in a given area and then is pitched to wherever you want the water to go. When we say pitched, we mean the ground is sloped to allow the water to roll downhill within the swale.” 

swale example
To help understand, here is a photo that shows a main trail and a swale dug out to the left at a diagonal. In the woods, there are often more than one swale.

On site, two swales were dug by hand and with the use of a small excavator/bucket on the driveway. (See Image 4) They will need to be maintained and dug out periodically to make sure they are still deep enough to do their job. A third was dug immediately in front of the house as an additional deterrent to keep water away from the foundation. 

Image 4: One of the swales created on the driveway. It drains diagonally downhill from left to right. The rock on the right is not a part of the swale.
Image 5: Another of the swales created on the driveway. It drains diagonally downhill from lower right of the picture to upper left.

Six to 8 inches of gravel were added to the drive lower down. We graded it and the parking area below the drive, to get the water to drain away from the house and over to the edge of the yard. 

Image 6 shows all the swales and the more directed drainage. The swales will slow the wash of the gravel and direct it so that the hillside will not continue to be covered in gravel. Work remains to be done in the side yard. Simple beginning solutions include the application of hardwood mulch and planting of additional groundcover. 

Image 6: Looking down the drive, the three swales appear in the picture as darker grey shadows across the driveway.

What is the water on your property doing? Does it drain away from the house? Is the driveway doing what you want and need it to do? Every lot and every house present a different set of drainage issues. Call or email Art of Stone to discuss the situation at your place.  

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