Developed in the 1990s on the basis of the Australian "Water Urban Design" (WSUD) approach to sustainable water management, rain gardens are intended to encourage the natural hydrological cycle, and to slow down and purify rainwater by infiltrating into the ground and replenishing the water table.

Massive soil sealing in the urban environment has always created major problems of surface runoff with increasingly frequent flooding due also to the effects of climate change.

Rain gardens are designed to control the process of rainwater infiltration in an urban environment or in predominantly sealed spaces. They are characterized by a slight depression in the ground where the water is collected and by a soil stratigraphy that favours slow infiltration. The vegetation is composed of ornamental species that can withstand temporary submersion and are also able to carry out a partial filtering action of certain pollutants and solids transported by rainwater.

In addition to these functions, rain gardens can be designed to create suitable habitats for certain species that can find favourable conditions for refuge and nourishment.

he following species can be found in this raingarden: