Who can talk about the basic connotation and design principle of rain garden?

Rain garden is a light green space that imitates the collection and leakage of rain in nature. It is mainly used to collect and absorb rainwater on the roof or ground, and purify the leaked rainwater through the comprehensive action of plants and various filling layers. The purified rainwater can not only supplement groundwater, but also be used as urban landscape water and toilet water.

(New Curriculum Standard 20 15) The main purpose of laying bark mulch is to keep soil moisture.

(New Curriculum Standard 20 15) The filling layers that play a major role in the purification of infiltration rainwater are planting soil layer and sand layer.

(20 15 New Curriculum Standard) The core function of rainwater garden is to control and utilize rainwater.