Analyzing the impact of hydrological storage and connected impervious area on the performance of distributed kerbside infiltration systems in an urban catchment

Abstract

The popularity of subsurface distributed storage-based kerbside stormwater infiltration systems is increasing because they can be integrated within the strict spatial constraints of existing infrastructure. Distributed systems operate based on the concept of spreading a limited amount of storage throughout the catchment area to achieve runoff management objectives. Storage can also limit the performance of urban stormwater systems. This study investigated the role of storage capacity, especially the volumetric capacity and the emptying time, in the performance of kerbside leaky well systems in a residential catchment area with a native clay soil environment. A detailed, process-based deterministic hydrological model was used to analyze hydrologic storage via a continuous simulation approach. The model was calibrated against catchment outflows measured with stormwater infiltration devices. Individual kerbside infiltration systems were also calibrated to monitor the behavior of on-site kerbside infiltration systems. By using approach of continuous simulations during designed scenarios, this study considered the prestorm storage availability in the hydrological analysis. The results demonstrated that hydrologic storage greatly influences the performance of kerbside leaky well systems during higher-intensity storms. In addition, the results show that distributing a stormwater storage volume equal to thirty-five 1-kL rainwater tanks across the catchment area as a kerbside infiltration system could notably reduce the runoff flow rates and volumes. The results further highlight that the addition of more homes within the connected area could diminish the stormwater reduction benefits achieved through the installation of a distributed kerbside infiltration system.