Enhancing stormwater management: Bridging data gaps to guide ecosystem protection

Current management of runoff from urban developments in Australia is underpinned by the use of generic load reduction objectives. Appointment of these percentage load reduction targets was, at the time appropriately and heavily, influenced by international stormwater quality data collated prior to 1995 (Makepeace et al., 1995). Recent research is raising questions about the appropriateness of guiding stormwater managing via such historic data sets and the use of percentage load reductions of traditional nutrient indicators that do not identify whether the nutrient is in particulate or dissolved state. Drapper et al. (2022) observed mean concentrations for Total Suspended Solids, Total Phosphorus and Total Nitrogen across 77 urban East Australian catchments between 1993-2021 to be 30-60% lower than reported in the international data set. Szota et al. (2024) propose new or additional indicators of pollutant removal rates are required to gain a more cost effective and comprehensive understanding of stormwater quality and the performance of treatment trains. The need to understand concentrations of contaminants in stormwater for effective protection of receiving waters and their ecosystems is undisputed. However, changes in urban design and density, climate, construction and transport technologies, and anthropogenic behaviours post 1995, make a review stormwater quality data specific to Australian catchments timely. This research seeks to bring together published and grey data sets held by governments, industry and research institutions specific to runoff from urban Australia catchments. It will identify patterns in parameters used to characterise stormwater quality across different sectors and provide knowledge of how the concentration ranges for traditional stormwater quality indicator compare to those guiding stormwater management modelling software such as MusicX. The research will also provide recommendations regarding the appropriateness of adopting additional parameters as standard measures for characterising stormwater quality.