Estuary water quality data has been collected by the Estuaries and Catchments Team of the Environment, Energy and Science Group in the Department of Planning, Industry and Environment since 2007. Data has been collected using a standard monitoring protocol outlined in 'Assessing estuary ecosystem health: Sampling, data analysis and reporting protocols. NSW Natural Resources Monitoring, Evaluation and Reporting Program', most recently updated in 2016 and available on the NSW environment website. The data has been used to monitor the aquatic ecosystem condition of over 160 estuaries in NSW over time. Adopting the principles of the National Water Quality Management Framework, the data has been used to develop NSW specific guideline values for a range of physico-chemical water quality indicators for each estuary type. This allows comparison of observed data to these guidelines to assess condition of any estuary in NSW. As part of the Marine Estate Management Strategy Implementation Plan Stage 1, a NSW water quality database has been developed, where this data is now stored. Water quality monitoring in NSW estuaries is ongoing, and updated data will be made available routinely.

Estuary water quality data has been collected by the Estuaries and Catchments Team of the Environment, Energy and Science Group in the Department of Planning, Industry and Environment since 2007. Data has been collected using a standard monitoring protocol outlined in 'Assessing estuary ecosystem health: Sampling, data analysis and reporting protocols. NSW Natural Resources Monitoring, Evaluation and Reporting Program', most recently updated in 2016 and available on the NSW environment website. The data has been used to monitor the aquatic ecosystem condition of over 160 estuaries in NSW over time. Adopting the principles of the National Water Quality Management Framework, the data has been used to develop NSW specific guideline values for a range of physico-chemical water quality indicators for each estuary type. This allows comparison of observed data to these guidelines to assess condition of any estuary in NSW. As part of the Marine Estate Management Strategy Implementation Plan Stage 1, a NSW water quality database has been developed, where this data is now stored. Water quality monitoring in NSW estuaries is ongoing, and updated data will be made available routinely.

The Surface Water Science team in DCCEEW employs WaterNSW to monitor water quality at almost 200 sites every month within the major rivers and streams of NSW, through the State Water Quality Assessment and Monitoring Program (SWAMP). This data is used to understand long-term trends in water quality throughout NSW and to develop scores for the water quality index. An annual report is written for every major river and its tributaries within the Murray-Darling Basin as well as the major rivers of the North coast, Hunter and South coast catchments and published in the NSW DCCEEW Water Publications Library. These reports include background information for each catchment including extreme events, catchment use, monthly rainfall, daily flow and dam capacity data. The reports also show the water quality index rating for each site within the catchment as well as water quality data. A new addition has been made to the 2022-2023 reports which includes long-term trends in water quality over the last 10 years.

From October 2017 through September 2022, the National Water Quality Network (NWQN) monitored 110 surface-water river and stream sites and more than 1,800 groundwater wells for a large number of water-quality analytes, for which associated quality-control data and corresponding statistical summaries are included in this data release. The quality-control data—for samples that were collected in the field (at all 110 surface-water sites, 350 groundwater wells, and 16 quality-control-only sites), prepared in the laboratory, or prepared by a third party—can be used to assess the quality of environmental data collected by the NWQN through the estimation of bias and variability in reported results. The general analyte groups that were monitored at NWQN surface-water and (or) groundwater sites and have associated quality-control data in this data release include major ions, nutrients, trace elements, pesticides, volatile organic compounds, hormones, pharmaceuticals, radionuclides, microbial indicators, sediment, and environmental tracers. For each analyte group, the data tables contain results for one or more of the following types of quality-control samples, where relevant: blanks, matrix spikes, and replicates collected at field sites; laboratory blanks, reagent spikes, and matrix spikes prepared by the USGS National Water Quality Laboratory (NWQL) (quality-control samples prepared by other analyzing laboratories are not included in the current data release); and third-party blanks, spikes, and reference samples prepared by the USGS Quality Systems Branch (QSB). For each relevant analyte, tables of summary statistics characterize the frequency and concentrations of blank detections, the typical magnitude of and variability in spike and reference-sample recoveries, and the typical variability between replicate concentrations. Tables included in this data release: Table1_SiteList.txt: Information about National Water Quality Network sites that have associated quality-control data. Table2_AnalyteList.txt: Information about National Water Quality Network analytes that have associated quality-control data, including available aquatic-life and (or) human-health benchmarks and selected information regarding analytical methods. Table3_BlankData.txt: For all relevant analytes, results for blanks collected at field sites, prepared in the laboratory, or prepared by a third party. Table4_SpikeData.txt: For all relevant analytes, results for matrix spikes prepared in the field, matrix spikes prepared in the laboratory, reagent spikes prepared in the laboratory, or reagent spikes prepared by a third party. For matrix spikes, results of paired environmental samples are included. Table5_ReplicateData.txt: For all relevant analytes, results for field replicates and paired environmental samples. Table 6_ReferenceData.txt: For all relevant analytes, results for third-party reference samples. Table7_BlankStats.txt: For all relevant analytes, summary statistics for each type of available blank sample. Table8_SpikeStats.txt: For all relevant analytes, summary statistics for each type of available spike sample. Table9_ReplicateStats.txt: For all relevant analytes, summary statistics for field replicates. Table10_ReferenceStats.txt: For all relevant analytes, summary statistics for reference samples.

From October 2017 through September 2022, the National Water Quality Network (NWQN) monitored 110 surface-water river and stream sites and more than 1,800 groundwater wells for a large number of water-quality analytes, for which associated quality-control data and corresponding statistical summaries are included in this data release. The quality-control data—for samples that were collected in the field (at all 110 surface-water sites, 350 groundwater wells, and 16 quality-control-only sites), prepared in the laboratory, or prepared by a third party—can be used to assess the quality of environmental data collected by the NWQN through the estimation of bias and variability in reported results. The general analyte groups that were monitored at NWQN surface-water and (or) groundwater sites and have associated quality-control data in this data release include major ions, nutrients, trace elements, pesticides, volatile organic compounds, hormones, pharmaceuticals, radionuclides, microbial indicators, sediment, and environmental tracers. For each analyte group, the data tables contain results for one or more of the following types of quality-control samples, where relevant: blanks, matrix spikes, and replicates collected at field sites; laboratory blanks, reagent spikes, and matrix spikes prepared by the USGS National Water Quality Laboratory (NWQL) (quality-control samples prepared by other analyzing laboratories are not included in the current data release); and third-party blanks, spikes, and reference samples prepared by the USGS Quality Systems Branch (QSB). For each relevant analyte, tables of summary statistics characterize the frequency and concentrations of blank detections, the typical magnitude of and variability in spike and reference-sample recoveries, and the typical variability between replicate concentrations. Tables included in this data release: Table1_SiteList.txt: Information about National Water Quality Network sites that have associated quality-control data. Table2_AnalyteList.txt: Information about National Water Quality Network analytes that have associated quality-control data, including available aquatic-life and (or) human-health benchmarks and selected information regarding analytical methods. Table3_BlankData.txt: For all relevant analytes, results for blanks collected at field sites, prepared in the laboratory, or prepared by a third party. Table4_SpikeData.txt: For all relevant analytes, results for matrix spikes prepared in the field, matrix spikes prepared in the laboratory, reagent spikes prepared in the laboratory, or reagent spikes prepared by a third party. For matrix spikes, results of paired environmental samples are included. Table5_ReplicateData.txt: For all relevant analytes, results for field replicates and paired environmental samples. Table 6_ReferenceData.txt: For all relevant analytes, results for third-party reference samples. Table7_BlankStats.txt: For all relevant analytes, summary statistics for each type of available blank sample. Table8_SpikeStats.txt: For all relevant analytes, summary statistics for each type of available spike sample. Table9_ReplicateStats.txt: For all relevant analytes, summary statistics for field replicates. Table10_ReferenceStats.txt: For all relevant analytes, summary statistics for reference samples.