A driveway is a standard addition to most properties, but if you’re concerned about installing the most commonly used materials and their impact on the environment, there are other, greener options. A driveway can be defined as green depending on its permeability, the materials used, and the heat island effect.
Both concrete and asphalt surfaces have the ability to direct storm water. On the plus side, this means that water can be diverted from an area in which it would otherwise pool and cause damage, but on the down side, this can mean that town drain systems become overloaded. It also means that potentially useful water for your own property is drained away. If, however, your driveway is made of more permeable material, it has the ability to absorb much of this water, meaning that you’re not contributing to the problems that arise where storm water finally is released; these problems include the release of harmful chemicals into the ocean or other water ways, flooding, and erosion. Permeable driveways can be made from many materials, including crushed stone & seashells, pavers or permeable concrete. If you live in an area where snowfall is expected, a surface that stays in place after you shovel or snow-blow is optimal.
One great option for a green driveway is, once again, a permeable material. Permeable concrete can provide a smooth driveway that allows for water absorption into the ground, it is relatively inexpensive, and it retains curb side appeal for many years. If you do decide to go with concrete, consider the strengthening and green properties of flyash. This product is made from coal and will decrease the environmental impact of your concrete.
Pavers are another wonderfully green option, and can look very pretty, although they do take a little more maintenance during nice weather if grass is allowed to grow up between them. Less maintenance but providing an attractive foil to the pavers would be moss or another groundcover to fill in the spaces between the pavers, and this would also increase permeability.
Although more limiting (as most towns and cities would not allow for it), one of the most green driveways you could probably have is simply a dirt or gravel drive. Depending on the seasons in your location, the driveway might need less or more attention than another type of material (filling ruts, having it smoothed).
Heat Island Effect
Radiant heat is an issue that most paving jobs simply don’t take into account. A smooth black surface is going to absorb heat during the day (making it uncomfortably hot to walk across on a sunny day) but radiate it back into the environment at night. You might want to consider a more environmentally friendly gray or other lighter colour to lessen the heat island impact. If a lighter colour isn’t an option, consider planting shade trees or shrubs to help decrease the amount of direct sun your driveway might get, especially during the spring and summer months.
To gain a greater understanding about different types of pavement and asphalt, see our previous post titled ‘Different types of pavements‘