What are rain gardens?
Rain gardens are areas of native vegetation and plants that absorb rainwater (from roofs and other impermeable surfaces) before runoff can occur. They can be used on a household or community scale. There are many excellent publications on rain gardens, such as the University of Wisconsin’s "Rain Gardens: A Household Way to Improve Water Quality in Your Community."
Additionally, there are a number of other alternative stormwater management methods. They are outlined in Chapter 2 of the publication, The Practice of Low Impact Development (available at www.huduser.org/publications/PDF/practlowimpctdevel.pdf).