Investigation into the sediment accumulation processes that occur in permeable interlocking concrete paving systems in Australia

One of the guiding principles of water sensitive urban design (WSUD) is centred on mitigating adverse effects of urban stormwater runoff such as increased urban flooding and deteriorating receiving water quality. In WSUD, permeable interlocking concrete paving (PICP) systems are known to be an effective source control measure to reduce stormwater flows and pollution loads. However, little is known about the effective lives of PICP systems in Australian practice because of their relatively recent emergence as a WSUD technology. There is a perception that PICPs that are used as source control devices, and designed to infiltrate runoff, will tend to clog quickly and result in high maintenance and replacement costs. This paper presents interim results from a forensic investigation into the sediment accumulation processes that occurred in a PICP that has been in service for over eight years. Previous research literature on the clogging processes of PICPs is reviewed and the various methodologies used are examined. The main aim of this study, which included both laboratory and field work components, was to examine and quantify the sediment accumulation processes that take place within the various aggregate layers used in typical PICP systems under rainfall and runoff Australian conditions. Initial results of the forensic investigation are presented in the paper. The final results of this research will have significant long term implications for stormwater management in Australia. The research will provide the answers to various important questions relating to future implementations of PICPs and alleviate many of the perceived problems associated with these systems.