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.

A little solar powered wind

Today I was walking through a small earth day festival in my town and noticed an interesting looking fan. This fan, as it turns out, is installed into the attic of houses and pushed air out of the attic. What's so cool or even environmentally relevant about this? This fan is capable of reducing your electric bill in the summer, and it's solar powered! Since I just attended a lecture on solar power panels this past week I thought it was an interesting, smaller, and more cost efficient alternative to large panels which generate electricity but are costly to install.

The benefit to these fans is that they circulate air within the attic with the combined help of either a soffit or a gable vent, diagrams of which can be seen at the bottom of this page. The idea is that the vents allow air from the outside to enter, and the solar powered fan pulls the air that heats up in the attic out of the house. The fan is capable of moving air at a rate of 800 to 1200 cfm (cubic feet per minute). This prevents the air in your attic from reaching extremely high temperatures that are caused by the attic's stagnant air collecting heat from the sun heating the hot roof and keeping it insulated in there. This stagnant air collects and begins to radiate heat into the rest of the home. It also prevents the hot air in the rest of the home from rising up and radiate into the attic, and from there out of the house.

By circulating the air and keeping the attic and the house cooler, it reduces the need for energy on the airconditioning unit. Since this is one of the major energy consumers in the home during the summer, it will make a but impact on reducing cost. This reductiong is only possible because of the solar panel that comes attached to the fan. The unit is therefore not connected to the rest of the wiring of the house. The benefit of the fan being solar powered is that it operates during the highest concentrations of sun light. Since the highest need for cooling occurs when the sun is at its height, this system works out amazingly because it works it's hardest when it is needed the most.

One downfall is that it does cost slightly more than electrical systems according to one site, but if you consider the savings and that it doesn't have to have the extra connection to the electrical system, then it works out in the end to be more economical. The system to be very simple to install compared to other solar powered or electrical systems. There is also the advantage that this can be installed into any type of home with an attic. At the festival one woman was interested in installing one into her Victorian home. This therefore seems like a great way to retrofit a home to be more environmentally friendly and sustainable with minimal additions so that the character of the home is maintained.