Permeable Surface Driveways Reduce Run-off
I grew up on an asphalt street, and our house had an asphalt driveway. When we would visit my grandfather in Florida, I saw driveways that were two narrow concrete strips in grass. I thought they were way cool – so unlike my neighborhood! I guess I liked the greenery best.
We also lived at the top of a hill. I remember rainwater running down to the bottom where there was a small creek, which would unsurprisingly flood. This was fun stuff for me as a kid playing in the rain, but now I know that run-off is not a positive thing. Old-fashioned driveways like I saw in Florida are much better for the environment.
The importance of greenery
Water runs off a solid surface, such as asphalt or concrete. It will flood a neighborhood or run into a storm drain, picking up oil and gas residues, pesticides, road salt and trash, all of which eventually ends up in a river or lake. Rainwater and snowmelt should be watering the ground it lands on, not some far away body of water.
If a driveway is partial grass, water can soak into the soil instead. This helps the land, recharges aquifers, and reduces wasted, polluted run-off. Grass and soil will filter storm water, and return clean water to the water table.
The driveways in Florida I liked as a kid are called Hollywood or ribbon driveways. They originated in the 1920s, and I think they should make a comeback! They use much less impervious material than a paved driveway, are less expensive to install, and lend themselves to a wide variety of groundcovers.
The strips can be made of things besides concrete. Permeable pavers with planting pockets can make a lattice or checkerboard design in the strips. These pavers now come in heavy-duty recycled plastic for an even more environmentally friendly driveway. And you don’t have to stick to installing strips! You can do your entire driveway or parking area with them.
Permeable surfaces without the greenery
If you do not like the look of grass in your driveway, you can create a seemingly solid surface that serves the same purpose as plant material. Any type of block, brick or stone can be inlaid with sand (permeable) instead of mortar (impervious). Storm water will drain through the sand as it would through grass. Sand is also flexible and will give with freeze/thaw cycles, and it does not pack down. It will stay porous.
Your driveway can be a work of art with bricks, pavers or stones, too. Find unique shapes for some fun curb appeal. Lay them in something more interesting than a grid, or combine them for a one-of-a-kind driveway in your neighborhood. Get creative!
Stones of various sizes are visually attractive, like cobblestone roads from centuries ago. You can be green without the greenery by finding local stone, too.
Good old-fashioned gravel is a permeable surface. I’m a big fan of crusher fines, which are tiny pieces of gravel that are tamped down to make a porous surface as hard as concrete. Water moves through it, instead of over it and down the road. It is great for walkways, and I’m sure it would make an effective, greenery-free driveway.
So if your driveway needs a makeover, choose a permeable option. Run-off might be fun for kids to splash around in, but it’s something we should try and avoid. Greenery or not, permeable surfaces are green.