Ten Steps Toward Sustainability -- Step 9: Support Green Roofs and Porous Pavement

Municipalities can build green roofs on city structures and create incentives for private building owners and developers to use them. Green roofs typically have a layer of soil with plants; their greatest advantage is water management, since they can absorb 50-60% of the rainwater that falls on them. This means that storm water enters the municipality's drainage system in a slow, controlled flow, rather than the typical high-volume surge from impervious surfaces that frequently cause storm water overflows to mix with sewage. Green roofs also help buildings stay cool in the summer and retain heat in the winter. Portland, Chicago and Toronto all have green roof programs.

Similarly, porous pavement can reduce storm water flooding and pollution by permitting water to pass directly through concrete or asphalt into the soil rather than sheeting off. Philadelphia recently announced it intends to use porous pavement in its storm water management program.

For general information on green roofs, see www.greenroofs.com.