Here in the Pacific Northwest, we get a lot of rain. Sometimes it comes in sheets, and sometimes it comes in a drizzle, a little each day for a week or two.
All this rain can take a major toll on our stormwater systems, rivers and lakes. The rain needs somewhere to go, and when it hits hard surfaces like streets and driveways, it tends to run sideways, carrying contaminants and debris along with it.
However, not all hard surfaces need to create runoff. Below are some ideas for driveways or parking areas that allow rainwater to soak into the soil while providing a solid base for your vehicle.
Concrete or brick pavers: Interlocking pavers or bricks themselves are impervious, but because they are installed with open space in and between them, they can act as pervious surfaces. Pavers come in all shapes and sizes, and one of the cool things about them is that you can allow grass to grow between the pavers, creating interesting patterns. A downside, of course, is that then you’d have to mow the driveway.
Plastic grids: Grids made of plastic serve much the same function as pavers. They provide a hard surface that resists potholing and erosion while ensuring that most of the ground remains pervious. As with pavers, though, one thing to remember is that the exposed ground can become quite packed, reducing the permeability of the driveway. That is why most gravel driveways, for example, are considered impervious surfaces.
Parking strips: One simple way to reduce the area of impermeable surfaces is simply to, well, make the area smaller. Parking strips — areas of concrete, tile, brick or a similar nonporous surface — can be placed just where the car tires would go, leaving the rest of the space for grass or low-lying ground cover.
Porous asphalt: Porous asphalt looks similar to traditional asphalt — that black road surface that you’re familiar with — but with air pockets, or voids, that allow rainwater to filter through the surface instead of running off into stormwater ditches. Here is a video showing the construction and demonstration of porous asphalt.
Pervious concrete: Like porous asphalt, pervious concrete provides a completely solid surface, unlike plastic grids or concrete pavers. In fact, pervious concrete looks almost like traditional concrete, so it is an excellent option for homeowners who want the look of a standard driveway with the performance of a non-pervious surface. In fact, pervious concrete has many uses around the home and is free of many of the issues that plague porous asphalt. As a Bellingham concrete contractor specializing in pervious concrete, Custom Concrete has installed pervious throughout Whatcom and Skagit counties. We think pervious concrete is the best option for environmentally friendly surfaces at home.