[Hydrological Performance Assessment of Permeable Parking Lots in High Water Areas]

In order to evaluate the hydrological performance of permeable pavements in mitigating the surface runoff, four pilot-scale permeable pavement units were constructed in Shanghai and compared with impervious pavements. Three of the permeable facilities with waterproof liners included a pervious concrete pavement (facility Ⅰ), permeable interlocking concrete pavement using cement stabilized macadam as the base course (facility Ⅱ) and permeable interlocking concrete pavement using macadam as the base course (facility Ⅲ). The other two facilities were a conventional permeable interlocking concrete pavement without a liner (facility Ⅳ) and an impervious concrete pavement control (facility 0). V-notch flow meters, data loggers, and a rainfall meter were mounted to monitor the hydrological data. A double-ring infiltrometer was applied to evaluate the infiltration rate of the pavements. During the one-year experiment, the surface runoff and the underdrain discharge flow rate of the four pilot-scale facilities were continuously monitored in actual rainfall and the total volume reduction, peak flow reduction, and peak concentrating time of different facilities were investigated. The results showed that the surface steady infiltration rates of permeable interlocking concrete pavements were less than those of the pervious concrete, and the surface steady infiltration rates of the two types of surface layers decreased after one year of usage. The surface runoff reduction of the four facilities showed no significant differences. The water volume reduction rate of the three types of facilities was weak. The annual total volume reduction rates were 24.2%, 28.5%, and 28.4%, and the controlled rainfall amounts were 5.2 mm, 7.8 mm, and 7.8 mm. The peak flow reduction rate and the time to the peak flow of facility Ⅰ were smaller than those of facility Ⅱ and facility Ⅲ. The peak flow reduction rate and the time to the peak flow of the three facilities showed significant negative correlation with rainfall intensity.