It is the massive amounts of runoff from these parking lots that actively transports trash, debris, silt, and other pollutants into the city s drainage ways, waterways, and ultimately the Gulf of Mexico. This water that is unable to penetrate the surface of an asphalt or concrete parking lot must be disposed of and is directed into ditches and canals, where trash and debris on the ground are picked up by the water and carried into the streams and creeks of the Dog River Watershed. With every rain, parking lots drainage systems are flooded with runoff containing pollutants that drip from cars and accumulate on the asphalt below. These metals enter the creeks and streams when rainwater washes them from parking lot surfaces and can be very dangerous to the environment. Another interesting point to consider is that since asphalt is impermeable, water is often left standing on the surface of the pavement after a rain.
Stagnant water can become a breeding ground for insects and harmful bacteria.
These pests and other insects would be considered a nuisance to the area s residents , and oftentimes impermeable parking surfaces play an integral part in birthing these aggravating insects. Another problem with impermeable parking lots that is not so obvious, is their effects on the local weather. In the summer time, blacktop asphalt absorbs much of the solar energy that would otherwise be reflected by natural surfaces. When the asphalt heats up, local convection currents, or updrafts, are formed by the heat accumulated in the surface of the blacktop, i.e. thermal pollution. This causes the air above the ground to rise.