Porous Paving

Why use porous pavement instead of regular concrete or asphalt?
- allows more land area to absorb water
- reduces runoff into storm drains by creating a larger reservoir for storm water
- this reduces the risk of flooding or overflowing of drainage networks
- reduces the cost of maintaining storm water infrastructure such as drains and retention ponds

By paving with this new type of aggregate, the adverse effects of blocking off so much land which would naturally filter water and create a groundwater reservoir would be alleviated. Instead of increasing runoff when it rains, the pavement will help draw down water into the ground, which will recharge groundwater reserves in the form of aquifers. Toxins which would normally be found in the runoff and added directly to streams will be eliminated by natural filtration through the ground. This will ensure a more reliable supply of water for future generations who live in the area. The health of the ecosystems around the area will also increase, including the vegetation bordering any roads which will receive a more gradual supply of water from the broader infiltration area. Since groundwater serves as the fresh water supply for most areas around the globe, this is a very important feature for our future habitation of many areas of the world.

The porous pavement also has the benefit of maintaining cooler temperatures in the paving areas and in surrounding streams where water normally heated after pooling on the pavement would drain to. It has the potential to reduce the "urban heat island effect" and the increased heath of surrounding plants can also reduce the heat normally radiating from paved areas. Since some of these systems include planted turf as the top layer, and help surrounding vegetation grow, it could be considered that the pavement helps reduce our carbon footprint by absorbing CO2.

There are a few requirements for the area however. The soil type must be able to drain at least a certain amount of water or it will still pool up and possibly harm the structure of the porous pavement. A few different types of porous pavements and what they consist of can be found here. Because the system has multiple layers, it must be deeper and more carefully engineered than any average road. There is also some maintenance requirements, which are not present for normal paving, that differ depending on the type of paving used. We can all do our part in reducing the damage done by normal paving by using simple methods of porous paving in our own driveways. This may be as simple as using crushed stone or seashells which do not hinder water percolation as normal asphalt driveways do.