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Marin IJ Articles

Permeable landscaping can be good for you and the Earth

  • Karen Hamblett
  • I don't know about you, but whenever I see someone's driveway or walkway with a well-designed permeable landscape — any type of landscaping that allows water to seep through — I'm always impressed and wish I could completely redo my own.

    If you are fortunate to be in the beginning stages or redesign phase of your home's driveway or walkways, there are lots of options worth considering. Even if you aren't in a redesign phase, there are things you can do to improve the look of your landscaping and won't be detrimental to the environment.

    So why should you consider permeable landscaping as an alternative to begin with? Preventing water runoff from rain or irrigation systems by allowing it to drain into the ground reduces the amount of pollutants that flow into the street and storm drains and ultimately into the ocean.

    According to the Sierra Club, "Just a 30-by-30-foot patch of concrete can shed over 550 gallons of water in a 1-inch rain. Multiply that by thousands of homes, and you're talking a tidal wave of potentially tainted H2O." Runoff water also can contribute to erosion and reduces the amount of water table replenishment in your immediate area.

    One benefit that hits closer to home is that replacing your asphalt or concrete driveway or walkways can reduce temperatures around your home. You know when you step out of your car on a hot day in a large parking lot how it feels significantly warmer? That's because the heat-absorbing quality of asphalt increases ambient air temperatures. Less asphalt means cooler temperatures around your home.

    There are a variety of permeable materials and ways to use them that create different looks. Have you noticed that more medians on streets are being planted to allow for some permeability? You can do the same in your driveway by cutting in a grassy "median" in your driveway using a sturdy plastic honeycomb base that will reduce runoff.

    Recall those old-fashioned ribbon driveways? Check out this blog for some beautiful photographs of some: tinyurl.com/mtc9f54. I've seen a variation of this design with an all-over honeycomb design using grass in front of several homes locally, and they look just lovely.

    Another option is a permeable paver system. The University of Delaware describes permeable paver systems as "specially fabricated paving units designed to replace asphalt and other impermeable paving materials. Interconnected pore spaces within the material channel water into the underlying soil or into a special storage layer which forces slow percolation during periods of heavy rainfall. Permeable pavers are often laid on a bed of sand or gravel to enhance drainage properties."

    If you're wedded to the look of concrete or asphalt, there are permeable options available to you. Pervious concrete and porous asphalt are mixed using less fine material to allow more water to seep through while maintaining their durability.

    You can create beautiful walkways around your home and throughout your garden using small smooth stones or pebbles laid on sand and soil. They are the least expensive to install but require more maintenance if they are heavily used as the stones displace easily. A combination of pavers laid in small pebbles works well, too. You can intersperse grass or low-growing groundcover plants between pavers, such as Creeping thyme (Thymus serpyllum), Baby tears (Soleirolia soleirolii) or Scotch moss (Sagina subulata).

    Keep your eyes open when driving around or visiting neighbors to see how beautiful and unique some permeable designs can be, and start envisioning what you can do in your space. Whatever steps you choose to take to incorporate permeable landscaping around your home, enlist the help of a professional familiar with local building codes and the installation of whatever material and method you select.