Chicago City Hall Green Roof project was started to curb the Urban Heat Island Effect.
Completed in 2001, the rooftop garden at Chicago’s City Hall was designed to test different types of green roof systems, heating and cooling benefits, success rates of native and non-native vegetation, and reductions in rainwater runoff.
The city of Chicago was forced to consider green roofing after a 1995 heat wave claimed a number of lives due to extreme inner city temperatures. Extreme temperatures are caused “Urban Heat Island effect” which is caused by the city’s concrete, buildings, and roads absorbing the heat, creating a very hot situation. Stormwater is also an issue, as the storm water and sewage systems are not equipped to handle heavy rains, often overflowing and causing sewage pollution during downpours.
Considering the sprawl of our cities to accommodate the ever-expanding population (let’s stop having so many kids, people!), building green roofs in our cities is the way of the future.
Studies have shown that on an overcast day at 74° the temperature on the roof is 74° reducing the pressure on indoor heat and air demands. A black tar roof would be 156° and even a highly reflective white roof would be in the range of 105-110° comparatively. Air quality is increased, storm water runoff is managed more effectively and the heat island effect is greatly mitigated by green roof installations.
Citing that a new generation of civil engineers is looking into the benefits of green roofs, Ed Snodgrass, an author on the subject, feels the primary drivers are storm water management, energy savings and moderating the heat island effect. As a living system, a green roof solves many of these problems simultaneously and does it mostly for free he says. Source: www.growingagreenerworld.com/episode122/
Denver Green Roofs:
In Denver, green roofs are also popping up. Some of the green roofs in Colorado include buildings at: Denver Botanic Gardens, and on the U.S. Environmental Protection Agency (EPA) Region 8 Office in Denver.
It’s great to see Denver companies specialize in Green roofs including Green Roofs of Colorado, so I am excited to see more projects popping up in our super-sunny city!
Read more about the greening of Chicago’s City Hall roof here: www.asla.org