Abstract:The retention effects of three depths 10 cm, 15 cm and 20 cm of concave green spaces under the conditions of adding three padding matrixes of volcanic, coal cinder and zeolite are studied. The influences of adding three paddings of volcanic, coal cinder and zeolite on the decontamination effects of concave green space are inspected. The results show that the greater the concaving depth, the better the reduction effect of green space on rainwater. But for safety reasons, the concaving depth should be controlled within a certain safe range. The different paddings will also affect the retention and decontamination effects. The retention effect of the device with the added volcanic is relatively good. The removal efficiency of total phosphorus is also good, and its removal rate is 82.7%. The removal rate of total nitrogen with the added coal cinder is the highest, and is 48%. The removal rate of COD with the added zeolite is the best, and is 34.9%. The removal rates of SS are all higher by adding three materials, and are about 95%.