Comparison of Runoff Control Performance by Five Permeable Pavement Systems in Zhenjiang, Yangtze River Delta of China

Abstract

Urban stormwater management measures, such as permeable pavement systems (PPSs), have been widely implemented to alleviate increasingly severe urban water-related problems. However, the effectiveness of PPSs in runoff control under different rainfall conditions has not been fully investigated, particularly in China. Therefore, there is an urgent need to study the hydrological benefits of different PPSs in China. In this paper, five PPSs at the Zhenjiang sponge base, including one pervious concrete (PC), two permeable interlocking concrete pavements (PICP1 and PICP2), and two permeable bricks (PB1 and PB2), were selected as study cases. Surface runoff coefficients, underdrain runoff coefficients, total runoff volume reductions, and peak flow reductions during rainfall events throughout the flood seasons of 2019 and 2020 were calculated. The influence of rainfall characteristics, pavement type, and pavement age on PPS hydrological performance were evaluated by statistical analyses (p<0.05). The results revealed that the average values of surface runoff coefficients, underdrain runoff coefficients, total runoff volume reductions, and peak flow reductions by the PPSs were approximately 0.025, 0.003, 98.1%, and 96.4%, respectively, in 2019 and changed to 0.045, 0.001, 96.3%, and 92.4%, respectively, in 2020. PC performed best with regard to surface runoff control at the initial stage of operation, followed by PB and PICP. Both rainfall depth and rainfall intensity had a significant correlation with each hydrological performance metric. The increase in surface runoff generation from 2019 to 2020 mainly resulted from the clogging problem, which was closely related to pavement type and surroundings of PPSs. PB performed better than PC and PICP in terms of sustainable hydrological performance. The results provide a scientific reference for the design, construction, and operation of PPSs and can aid with the sustainable construction of sponge cities in China. This study evaluated the runoff reduction performance of five PPSs under natural rainfall events, which were observed during the flood seasons of 2019 and 2020 in Zhenjiang, Yangtze River Delta of China. In total, approximately 96% of the rainfall was captured by the PPSs during the monitoring period, and the PPSs performed better in lower-intensity rainfall events. However, the runoff reduction performance of the PPSs decreased markedly with operation time due to clogging, which is closely related to the pavement type and site surroundings of the PPS. To maintain the function of PPS for runoff control in a long period of time, the permeable brick system is the best type of PPS compared with PC systems and PICP systems. The results indicated that the application of PPSs in sponge city construction could be beneficial in the mitigation of urban floods, and adequate attention should be paid to the clogging problem of PPSs at every stage of PPS design, construction, and operation.