With increasing human populations in coastal regions, there is growing concern over the quality of wastewater treatment plant (WTP) discharge and its impacts on coastal biodiversity, recreational amenities, and human health. In Australia, the current system of WTP monitoring and reporting varies across states and jurisdictions leading to a lack of data transparency and accountability, leading to a reduced ability to comprehensively assess regional and national scale biodiversity impacts and health risks. The National Outfall Database (NOD) was developed to provide a centralized spatial data management system for sharing and communicating comprehensive, national-scale WTP pollutant data. This research describes the structure of the NOD and through self-organizing maps and principal component analysis, provides a comprehensive, national-scale analysis of WTP effluent. Such a broad understanding of the constituents and level of pollutants in coastal WTP effluent within a public database provides for improved transparency and accountability and an opportunity to evaluate health risks and develop national water quality standards.

This report provides a preliminary data analysis of the river outfalls around the Hawkesbury-Nepean coastal catchment areas located in central NSW, and ranks them according to the total flow volume and nutrient load to determine the potential health and environmental impact.  The main targeted audiences are decision makers, water authorities and general public.  The key points of this report are 1) higher nutrient discharged is mainly in the lower catchment areas, 2) larger capacity Waste Water Treatment Plants (WWTP's) discharge the highest nutrients load into the catchment areas, 3) inconsistency within the datasets which makes the analysis difficult to conclude the extent of nutrient impacts in the inland river.  Improved Australia-wide inland outfalls monitoring is needed to identify the extent outfalls impact on water quality and riverine ecosystems.  A standardised format of dataset is required to help researchers and stakeholders to assess water quality data of WWTP outfalls.