The Chicago City Hall roof garden is the first example of economical and sustainable water management in roof planting, in the City of Chicago. Visitors can enjoy a stroll along curving paths of lightly contoured landscaping. Varieties of sedum, compliment the trees and shrubs planted on both shallow and deep substrates across the roof of the City Hall.
Chicago is one of five major US cities taking part in the Environmental Authority's “Urban Heat Island Initiative” pilot project. The initiative seeks to reduce the temperature and smog levels in several US cities. Roof planting is one of the key elements of the program, which is also intended to relieve overloaded sewers during heavy rainfall.
Parts of the roof were removed for statical reasons prior to landscaping, with water provisions for the roof plants embedded in the process. Rainwater from the penthouse is stored in several small tanks and supplied to the plants when needed.