Effect of Permeable Block Performance on the Urban Water Cycle

Due to the rapid changes in precipitation patterns resulting from ongoing climate change, urban watercycle problem associated with extreme rainfall events are becoming increasingly severe. In response, the Ministry of Environment of Korea introduced the concept of Low Impact Development (LID) in the 2000s and has implemented stormwater runoff reduction facilities nationwide. This study investigates the impact of permeable block performance, one of the most widely adopted LID facilities, on the water cycle in urban drainage.

Initially, experimental analyses were conducted to assess the fundamental performance and clogging-induced degradation of various types of permeable blocks. These evaluations focused on examining the basic functionality of the blocks and the impact of clogging on their performance. Based on the experimental findings, the SWMM model was employed to investigate the effects of permeable block performance on hydrological processes across watersheds of varying scales.

The results indicated that the application of permeable pavement significantly improved the water cycle regardless of watershed size, with the extent of improvement dependent on the coverage area of permeable pavement. Notably, infiltration showed the largest increase across all watersheds, followed by increased evaporation and reduced surface runoff. In terms of peak runoff, significant reductions were observed in watersheds where permeable pavement covered more than 10% of the total area, although the reduction effects were marginal in most regions.

An investigation into the effects of clogging revealed that, compared to the initial installation phase, infiltration decreased by up to 34.2%, evaporation by up to 3.2%, and surface runoff increased by 0.7%. Furthermore, the study confirmed that clogging had the most substantial impact on the performance of permeable blocks, with performance degradation becoming more pronounced as block porosity increased.

These findings highlight the necessity for future research to establish correlations between porosity and clogging and to identify optimal porosity levels. Moreover, effective policy interventions are required to mitigate the impact of clogging by preventing the ingress of debris from the surrounding environment.

 

Accknowledgement

This work was supported by Korea Environment Industry & Technology Institute(KEITI) through R&D program for innovative flood protection technologies against climate crisis, funded by Korea Ministry of Environment(MOE)(RS-2023-00218973)