Making Parking Lots more Water Friendly

Making Parking Lots more Water FriendlyWhen it comes to water conservation and reducing stormwater runoff, everyone has a part to play from homeowners and landlords to businesses and developers. One way business and developers can increase their role in stormwater reduction is through the installation of rain friendly parking lots.

Parking lots cover large areas of what would otherwise be permeable soil. When it rains, the rain that used to soak into the ground at the site now becomes runoff. And, since it runs off through a parking lot, it picks up pollutants like oil, grease and other fluids from cars.

Parking lots deal a double whammy to stormwater and wastewater management. First, they increase stormwater volume and secondly, the runoff requires additional treatment before it can return to the water supply. There is a better way.

Going Permeable

Businesses require parking lots for their customers. That’s a simple cost of doing business. However, developers and current business owners can make different choices about how to build those parking lots.

Permeable, or porous, parking lots are one of the latest trends in green building design. Instead of using concrete or some other surface that water can’t penetrate, these parking lots utilize materials that allow water to seep through.

Once the water seeps through the porous materials, it collects in a reservoir. Here, it can either return to the soil much like it would in a rain garden (passing through layers of rock and gravel to help clean the soil) or return to the stormwater system, but in a more measured flow than standard parking lot runoff.

Chances are, you have seen a permeable parking lot before. The Capital Regional District in British Columbia advocates for them. And the Cement Association of Canada considers them an ideal solution to manage stormwater runoff, actually reducing the need for other runoff management systems.

Materials in Permeable Parking Lots

Developers can choose between two methods of constructing permeable parking lots — pervious concrete and permeable interlocking pavers.

Pervious concrete looks a lot like a rice cake. It is made in much the same way as traditional concrete but with a lower sand content. It can allow 200 litres of water per minute to pass through it to the soil below.

Interlocking pavers come in a variety of styles and many call for allowing grass or other low growing herbs to grow up within the paver grid system. Interlocking paver systems are typically used more in residential projects or projects with lower traffic volumes, like parking strips or walkways.

Benefits of Permeable Parking Lots

The benefits of permeable parking lots are similar in many ways to the benefits of rain gardens. Choosing this type of parking lot can bring about both positive environmental benefits and monetary benefits as well. They include:

  • Reducing overall stormwater runoff;
  • Recharging the groundwater;
  • Reducing heat islands, especially in an urban environment;
  • Preventing warm water runoff from affecting native marine life;
  • Increasing a building’s LEED point value for green building;
  • And reducing the need for other, costlier stormwater runoff management systems like retention ponds, pumps or drainage pipes.

Some utilities may even provide grants or other creative funding solutions to help businesses install these parking lots because they help the entire system work more efficiently and ecologically.

Water, our most valued and shared natural resource, needs us all to do our part to ensure the long-term health of our water systems. Wildlife, developments and residential users don’t need to compete against each other to secure the water they need. Innovative solutions like permeable parking lots help us work together to make sure we have enough water for all who need it, both now and into the future.

Liquid Assets WCW13

Register Today