I like the idea of rooftop gardens. Maybe this could work here in Sherman Oaks.
Nine Cities, Nine Ideas
Local governments around the globe are coming up with some of the most innovative ways to cut energy use. There are lessons here for places of all sizes.
CHICAGO
LET YOUR GARDEN GROW
About eight years ago, the Windy City began overhauling 15 million square feet of its municipal buildings to make them use less power. On many of the buildings, city officials decided to put in a novel feature: rooftop gardens.
The first was planted atop the 11-story Chicago City Hall, a nearly century-old landmark where the temperature on the roof -- as on many other downtown buildings -- would soar to as high as 160 degrees on hot days. Gardens can keep a roof as much as 70 degrees cooler, city officials say, because all the greenery reflects heat while providing shade. Consequently, less energy is needed to keep a building cool.
The City Hall garden, completed in 2001, covers about 20,000 square feet of the roof, using more than 100 hardy species that can withstand Chicago's fierce winds and temperature extremes. The savings were felt immediately, with the annual power bill for the building falling by 11%, or almost $10,000, city officials estimate.
Since then, the city has expanded the green-roof program dramatically. Now 4 million square feet of municipal and private rooftops either have a roof garden or are in the process of getting one, says Suzanne Malec-McKenna, Chicago's commissioner of the environment. In so doing, Ms. Malec-McKenna says, the city has made sure to use lightweight, permeable soils to keep the rooftops from becoming too overloaded. Waterproof membranes are also fitted below the garden to keep rain runoff and other water from leaking into the building.
A different kind of problem cropped up on the City Hall roof soon after it was finished. "We had a grasshopper invasion," Ms. Malec-McKenna says. "But thankfully the birds got them."
-- Jim Carlton (Wall Street Journal, February 11, 2008) To read full article go to wsj.com