Waterway Health Review

Hornsby Shire Council has monitored water quality to assess aquatic ecosystem health since 1994. This program is one of the most intensive monitoring programs undertaken by any Local Government in NSW.

In 2019, Council finalised a Waterway Health Review which analysed 22 years’ worth of data and provides a comprehensive understanding of the current conditions of our creek, estuary and river systems in combination with recommended management actions to protect Hornsby Shire’s highly valued local waterways into the future.

Significant Findings of the Waterway Health Review

  • In general water quality at most long-term freshwater sampling sites has remained relatively stable despite an ever-growing population and increasing development pressure
  • Waterways in urban areas generally have poor water quality through time
  • Long-term improvements in water clarity have been achieved at many freshwater sites, however, persistently elevated nutrient concentrations, electrical conductivity and pH remain an issue
  • Long-term improvements in phosphorus concentrations have been achieved at two out of three (Larool Creek, Thornleigh and Sams Creek, Mt Ku-ring-gai) monitoring sites associated with industrial land use
  • Estuarine sites in the Hawkesbury River are exhibiting impacts from pressures that extend well beyond the Hornsby LGA, particularly with regards to increasing nutrient concentrations
  • Most sources of faecal bacteria in both fresh and estuarine waterways are associated with pulse, or intermittent, pollution events that are likely to be rainfall related
  • Significant improvements in nutrient concentrations are evident following the completion of Sydney Water upgrades to the Hornsby Heights and West Hornsby Wastewater Treatment Plants in 2003, however, no further improvements are evident since this time.

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