Finally, there is an alternative to impervious asphalt-paved parking lots that contaminate freshwater systems, increase pollution and flood risk, and have a biodiversity value of zero.
The sealants applied to protect the asphalt are known pollutants as well. Due to the harmful effects of asphalt, pervious concrete and vegetated swales are the latest trend in eco-friendly parking lots.
Pervious concrete has the same physical characteristics as concrete, but has storm water quality benefits of more permeable soils. It is made of stone particles held together by cement, which creates about 20% void space. This space allows absorption of more water than asphalt, which in turn leads to less water run-off.
The color of the pervious concrete is much lighter than asphalt, which allows for a cooler environment when compared to the heat island effect given off by asphalt.
A vegetated swale is an open, shallow channel containing attractive plant materials with an impressive ability to filter pollutants. Each vegetated swale tolerates inundation, and requires little summer irrigation.
When used together with pervious concrete, vegetated swales help reduce water run-off volume while protecting the quality of the water that does run-off into freshwater systems.
Ecological parking lots are proven to have less total water run-off, lower ambient air temperatures, and have vegetation grow faster and healthier than an asphalt parking lot. They are the latest trend in making cities across the world become eco-friendly.