A sustainable approach to urban stormwater drainage must integratethe entire urban drainage system. One way to achieve this is to maximize infiltration rates on the land lot by using rain gardens, which are a compensatory technique based on bioretention and waterproof areas compensation. This paper presents an experimental rain garden study, implemented in Recife, Brazil, evaluating the retention, storage and infiltration of the rainwater collected from the roof. Due to the high infiltration rates on the surface (312,0 mm/h), the waters quickly infiltrate into the structure. The models introduced by Horton and Mezencev were used to simulate the infiltration characteristics of the natural soil and those of the first layer of the rain garden, yielding satisfactory results. A financial cost analysis was carried out in order to estimate installation costs for recurrence times of 2, 5, 10 and 25 years, and rain durations of 10 min to 120 min. During the monitoring period,no overflow was observed. The pilot rain garden presented good results and proved to be a suitable technique for stormwater management.
Compensatory techniques; Urban drainage; Retention; Infiltration
