3. Education and Research: the rain gardens are the testing board that also visually displays the process of runoff controlling, rain water collection, cleaning and re-using.In the Ripple Gardens, the site is specially designed to visualize the water movement through the site. It becomes an educational facility to the visitor to understand the strategies behind the design. In the rain garden of windmill garden, the water cleaning process can be measured and recorded by a monitoring pond. The researcher can test the water quality there after storm. When the quality of water researches to a certain level, it will be led to a cascade and the reflecting pool for the visitors to enjoy.