Clogging Resistance of Porous Pavements and Investigation on the Effectiveness of Various Cleansing Methods

Abstract

<p>Permeable pavement (PP) adopts porous materials which features an open network of pores to allow infiltration of stormwater through the pavement into the base/sub-base layers. As one type of sustainable urban drainage system (SUDS) measures, PP is one of the most widely used stormwater management facilities in urban areas due to its good hydrologic performance and the advantage of no occupying extra space (Li et al., 2022). The hydrologic benefits of PP include mitigating the peak and volume of surface runoff, delaying the peak flow, and enhancing groundwater recharge (Liu and Chui, 2017), etc.</p><p><br></p><p>PP has gained increasing attention as a sustainable measure to deal with urban flooding in recent decades. However, one of the most significant concerns with PP is its ability to withstand clogging from continual and long-term usage (Hu et al. 2020). That is, the porosity of PP shows a loss of in-situ permeability over time due to collecting solids such as sediment and organic matter in stormwater runoff. And clogging would over time degrade the performance of PP. Regular maintenance should thus be carried out to minimize clogging and to retain the permeability of PP. In fact, the loss of permeability has been studied by many previous studies using numerical simulation and laboratory experiments (e.g., Pezzaniti et al., 2009). However, less studies evaluate the effective lifetime of various types of PP (i.e., the number of years that the PP will be fully clogged). And the maintenance effectiveness of various cleansing methods such as waterjet and vacuum has been investigated (e.g., Hu et al., 2020). Nevertheless, the effects of waterjet and vacuum pressures on the cleansing effectiveness has not been well understood for different PP.</p><p><br></p><p>This study aims to estimate the number of years that the PP would be fully clogged if no maintenance was conducted, and to evaluate the effectiveness of typical cleansing methods (i.e., waterjet and vacuum cleansing) on restoring the permeability of clogged pavers. The main ideas are to accelerate the clogging by introducing sediments onto the PP artificially in laboratory experiments and observe the degree of depreciation in permeability of PP after continuous simulated clogging conditions. Afterwards, the different cleansing methods are performed on the totally clogged PP to evaluate their recovery effectiveness. PPs are a major focus for Hong Kong’s Drainage Services Department (DSD) in their policy to implement SUDS in future stormwater management schemes. With Hong Kong’s challenging geology and high levels of urbanization, the benefits of making SUDS commonplace are numerous and hence the studying and evaluation of these SUDS designs will bring great value socio-economically and in public safety in an increasingly harsh climate.</p>