Water catchment projects

Hornsby Shire’s waterways are vital to our environment, lifestyle, and community wellbeing. That’s why we’ve launched a revised Catchment Health Program - a proactive initiative that combines science, action, and community care to keep our creeks and rivers healthy.

The program includes:

• A Sentinel Monitoring Program: We’ve set up 15 monitoring sites across the Shire to keep a close eye on water quality. These sites act like environmental “check-ups,” helping us detect changes early and respond quickly to any potential issues. The next round of intensive sampling will take place in 2026/27.
  
  

  Find out more

• A Bespoke Catchment Health Program: We've completed detailed investigations across six priority sub-catchments across Hornsby Shire to better understand local water quality issues and identify practical solutions. Investigations have now been completed, or are underway, to pinpoint pollution sources, assess risks to creek health and guide roll out targeted management actions to reduce pollution and improve waterway health. Findings are helping shape future works, education programs and policy improvements to protect and restore our waterways. These efforts will be guided by data from our monitoring program - so every decision is backed by science.

  The six priority sub-catchments are:

  • Upper Calna Creek (Asquith/ Hornsby)
  • Upper Still Creek (Arcadia, Galston, Berrilee)
  • Upper Laughtondale Gully Creek (Maroota, Laughtondale)
  • Upper Colah Creek (Dural, Galston, Glenorie, Arcadia)
  • Georges Creek (Glenhaven)
  • Pyes creek (Castle Hill, Dural, Cherrybrook)

  Find out more

Cleaner Industries, Healthier Waterways

Urban areas with heavy development often struggle with poor water quality in their creeks and rivers - a challenge known as Urban Stream Syndrome. In Hornsby Shire, this issue is especially relevant in our three main industrial precincts: Hornsby, Thornleigh, and Mount Ku-ring-gai.

These areas have historically contributed to pollution in nearby waterways. That’s why Council has launched a targeted program to improve water quality in these catchments through smarter monitoring, investigation, and action.

What we’re doing

• Our approach combines data, science, and collaboration to tackle pollution at its source:
• Analysing long-term water quality data to understand historical trends in industrial catchments.
• Profiling local businesses to assess their potential pollution risk using a risk-based framework.
• Tracing pollutants through the stormwater network to identify and address point-source pollution.
• Combining education and regulation to help businesses reduce their environmental impact.

Where are we at

• Completed preliminary desktop research and historical data analysis
• Commencement of business profiling and pollution risk assessment in Thornleigh

Next steps

• Building more informed understanding of potential industrial pollution sources through partnership with internal Environment Branch and Compliance teams
• Collaborating with the EPA in pollution source tracking programs within our industrial catchments
• Developing new compliance and education programs.

By working together with local businesses and the community, we’re taking meaningful steps to protect our waterways and create a cleaner, healthier environment for everyone.

At Hornsby Shire Council, we’re committed to protecting our waterways through science, innovation, and collaboration.

We’ve teamed up with researchers from the University of Technology Sydney to investigate water quality issues in urban catchments. We have completed an intensive monitoring program in West Pennant Hills, using microbial source tracking to pinpoint sources of contamination linked to sewer and stormwater infrastructure. Microbial Source Tracking is a scientific method that assist us in identifying whether faecal pollution in waterways comes from humans, pets, livestock, or wildlife, helping managers target the most effective response.

The findings helped with the development of targeted sub-catchment scale education programs, which is planned for implementation in 2026/27.

We’re also keeping a close eye on the health of the Hawkesbury estuary through a network of real-time monitoring stations. These stations provide up-to-date information on:

• Overall estuary health
• Swimming conditions
• Algal bloom alerts

View HawkesburyWatch Dashboard

This ongoing program ensures we can respond quickly to changes and make informed decisions to protect one of our region’s most important natural assets.

Tracking Recovery After the Floods

Between 2021 and 2022, eastern Australia experienced a series of devastating floods that left a lasting impact on our natural landscapes. One of the hardest-hit ecosystems was our mangrove forests—vital coastal habitats that help stabilise shorelines, filter water, and support marine life.

In the Hawkesbury River, these floods caused widespread thinning and dieback of mangroves across multiple estuaries. In response, Hornsby Shire Council’s Catchments team launched a long-term Mangrove Health Assessment to monitor the damage and track signs of recovery.

What we’re doing

• Annual Visual Surveys - Every year, we assess mangrove health along 33 kilometres of shoreline, from Bar Point to Wisemans Ferry, documenting areas of dieback and regrowth.
• Long-Term Monitoring Sites - We’ve established eight dedicated monitoring sites across the river, each representing different levels of flood impact. At these sites, we track three key indicators of mangrove health:
  • Seedling numbers
  • Pneumatophore density (the aerial roots that help mangroves breathe)
  • Canopy cover

This data helps us understand how mangroves are responding over time and guides future restoration and protection efforts.

Why it matters

Healthy mangroves are essential for clean water, climate resilience, and biodiversity. By monitoring their recovery, we’re not just protecting trees—we’re safeguarding the entire river ecosystem for future generations.

Previous reports 

• 2025-2026 Mangrove Health Assessment report(PDF, 2MB)
• 2021-2023 Mangrove Health Assessment Report(PDF, 16MB)

Every drop of water that runs off our streets, driveways, and rooftops eventually flows into our local creeks and wetlands. At Walumeda Wetland in West Pennant Hills, we’re working to raise awareness about how everyday stormwater runoff affects the health of Berowra Creek’s headwaters.

Listening to our community

So far, we’ve connected with residents through:

• A community survey
• An information display
• Local outreach events

The feedback we received has given us valuable insight into how the community views water quality and stormwater issues.

Curious about what people had to say? Read the Walumeda Catchment Community Survey Report(PDF, 4MB).

What’s next

Your input is helping shape the future of this project. We’re using what we’ve learned to:

• Design more effective education campaigns
• Encourage positive behaviour change
• Support the long-term health of Berowra Creek, Walumeda Wetland, and the surrounding stormwater network

Together, we can protect our waterways—starting right here in our own backyards.

Further information: YourSay project webpage.

Through the CRR program Council is investing in projects that protect and restore the health of our local waterways. One of the key tools we use is the installation of Stormwater Quality Improvement Devices - smart infrastructure designed to stop pollution before it reaches our creeks and rivers.

Currently Council is working on:

• Construction of two gross pollutant traps at Kenburn avenue, Cherrybrook
• Construction of gross pollutant trap at Glen Street, Glenorie
• Upgrade of Clarinda wetlands, Hornsby

The program also supports a number of pollution prevention initiatives such as environmental education, industrial auditing, street sweeping, and emergency spill response and pollution regulation. 

For further information on the current and upcoming CRR devices visit Current and Upcoming CRR Projects.