Catchments Remediation

The Catchments Remediation Rate (CRR) is a special rate paid by Hornsby Shire residents to fund projects that repair and protect local waterways.

CRR Annual Performance Report - 4MB

The Catchments Remediation Rate is levied at five percent of Council’s ordinary rates and raises $3 million each year that is used to install and maintain stormwater quality improvement devices within the Shire’s four major catchment (drainage) areas: Berowra Creek, Cowan Creek, Upper Lane Cove River and Hawkesbury River.

Why is the rate needed?

The 1970s and 1980s saw the increasing urbanisation of Hornsby’s sensitive bushland catchments and an influx of tens of thousands of new residents. Sediment runoff from developing and newly developed residential areas and nutrient pollution from sewage treatment plants contributed to the deteriorating quality of local creeks and estuaries.

Unsavoury smells from the natural waterways became more potent and more common; algal blooms were becoming more substantial and more frequent; run off and sewage overflows in wet seasons became more difficult to manage; frog watchers noted the loss of familiar species; recreational fishermen caught fish with black livers; bush walkers watched weeds intrude into relatively pristine natural reserves; indigenous plants died or were depleted by theft; and locals watched the sea grass retreat under increasingly muddy water.

Source: A New Legend - The Story of the Berowra Creek Community Contract

By the 1990s it was clear that Hornsby Shire’s waterways were under severe stress. Berowra Creek was being despoiled by instances of fish kills and algal blooms. Urgent action was needed.

A New Legend - The Story of the Berowra Creek Community Contract - 10.5MB

How did the rate come about?

To force the State Government to see how desperate the situation was Hornsby Shire Council placed a moratorium on the processing of any development application located within the West Hornsby Sewage Treatment Plant’s catchment area until action was taken.

The strategy worked and in April 1994 a Statement of Joint Intent (SoJI) was signed between Hornsby Shire Council, NSW Government, Environment Protection Authority, (Sydney) Water Board and the Hawkesbury-Nepean Catchment Management Trust. The principle intent behind this “community contract” was the ecologically sustainable development of Berowra Creek catchment and recovery of the environmental health of the Creek.

Original Signed Statement of Joint Intent (SoJI) 1994 - 625kb

The SoJI not only acknowledged the significant impacts of polluted urban stormwater run-off but instigated the upgrading of the West Hornsby and Hornsby Heights Sewage Treatment Plants (reducing nutrients through increased levels of wastewater treatment) and the creation of the CRR.

The following video gives a full account of the dramatic events that led to the creation of the CRR:

What projects does the CRR fund?

Since 1994 the CRR has funded the construction of more than 400 Stormwater Quality Improvement Devices (SQuIDs) across Hornsby Shire. These SQuIDs help improve the quality of stormwater by removing pollutants such as litter, sediment, nutrients and heavy metals. Projects include the following devices and works: Rubbish net

Biofilters (also known as Bioretention Basins or Raingardens) – vegetated sand filters that trap litter, remove sediment and filter out pollutants such as nutrients and heavy metals.
- Biofilter and Raingarden Factsheet - 122kb
- Examples of Biofilter interpretive educational signage:
Gross pollutant traps – a range of rubbish racks, baskets, nets and other infrastructure that remove litter, leaves and sediment from stormwater runoff.
Continuous Deflective Screening (CDS) devices – underground concrete chambers that screen stormwater by using a vortex action to capture pollutants.
Graduated trash racks – angled screens that use streamflow velocities to capture organic matter and gross litter pollution.
Sediment basins – trap sediment from stormwater preventing it entering waterways.
Artificial wetlands – similar to sediment basins but generally larger and vegetated by native aquatic plants.
Stormwater harvesting schemes – collect stormwater runoff to be reused for irrigation on playing fields and ovals.
- Examples of Stormwater Harvesting interpretive educational signage:
Leachate treatment facilities – treat polluted leachate from two of the Shire’s former tip sites at Arcadia Park and Foxglove Oval.
Creek remediation works – the stabilisation of creek and drainage lines to prevent further erosion.

Current CRR - Capital Works Projects

Three biofiltration basins have been constructed at Thomas Wilkinson Ave Dural, Cawthorn St (Rofe Park) Hornsby Heights and Lessing Park, Hornsby.
Three gross pollutant traps have also been constructed at Cawthorne St, Hornsby Heights , Lessing Park, Hornsby and Reddy Park, Hornsby.
Stormwater harvesting has been partially installed at Cawthorn St (Rofe Park) Hornsby Heights, once completed the harvested water will be used to irrigate Rofe Park.
A biofiltration basin , gross pollutant trap and stormwater harvesting is currently under construction at Normanhurst Park, Normanhurst.
A biofiltration basin is schedule for construction at Nirimba Avenue Reserve, North Epping and a gross pollutant trap is scheduled for construction at Margaret Ave, Hornsby Heights.

Site Location	Device	Completion
Thomas Wilkinson Ave, Dural	Biofiltration Basin	15-01-20
Cawthorn Rd ( Rofe Park), Hornsby	Gross Pollutant Trap , Biofiltration Basin & Stormwater Harvesting	24-04-20
Lessing Park , Hornsby	Gross Pollutant Trap, Biofiltration Basins	23-10-20
Reddy Park , Hornsby	Gross Pollutant Trap	06-11-20

Site Location	Device	Status
Normanhurst Park, Normanhurst	Gross Pollutant Trap , Biofiltration Basin & Stormwater Harvesting	Completed
Margaret Ave, Hornsby Heights	Gross Pollutant Trap A gross pollutant trap was completed in December 2021 at Margaret Ave, Hornsby Heights. The gross pollutant trap will provide treatment to stormwater flows by screening and capturing water pollution such as litter and floatable waste from entering our bushland and waterways.	Completed
Nirimba Reserve, Epping	Biolfiltration and Creek line Remediation A biofiltration basin and creek line remediation works were completed in November 2021 at Nirimba Reserve, Epping (photo attached). The biofiltration basin included plantings that will provide pollutant removal by supporting microbial processes that utilise nutrients amongst other pollutants. The project also re-established the natural features of the watercourse (i.e., plunge pools, settling pools etc.) that provide habitat and enhanced the ecological diversity of the site.	Completed

Environmental Benefits

Water quality / biological treatment of stormwater pollution.
Reduction of pollution loads impacting the terrestrial environment and waterways.
Enhancement and protection of indigenous habitat.
Reduction of wastewater flows and flooding impacts.
Reduction of the dependency of potable water and cost savings from reusing water.
Engagement of WSUD, ecological sustainability and water conservation practices.

CRR Device Definitions

Biofiltration Basins

Biofiltration basins are landscaped shallow basins used to slow and treat stormwater runoff . Stormwater is directed into the basin where the stormwater percolates through the system (media) underlying soils treating stormwater pollution (i.e. nutrients , bacteria and fine sediments )

Gross Pollutant Traps

Gross pollutant traps are screens that capture gross pollution such as litter, floatables and organic debris from stormwater runoff.

Stormwater Harvesting

Stormwater is harvested from surface drains, creeks and treated and reuse for irrigation. The process differs from rainwater harvesting whereby the water is collected from the roofs.

What else does the CRR fund?

Maintenance of stormwater quality improvement devices
Water quality monitoring and research
Environmental education
Street sweeping
Industrial auditing
Emergency spill response
Environmental compliance and management.