Catchment management

Image of SCA officers conducting hazard reduction burns.

The SCA has fire management plans for all Special Areas including hazard reduction burns.

The Sydney Catchment Authority (SCA) manages 16,000 square kilometres of drinking water catchment to protect the raw drinking water supplies for around 4.5 million people, or 60 percent of the state’s population.

To best protect water quality, the SCA adopts a multiple barrier approach, which includes:

  • protecting the quality of water entering the storages by monitoring and influencing activities in the catchment
  • improving the quality of water entering the storages by protecting and managing catchment lands (Special Areas) surrounding the storages
  • optimising management of the storages
  • having extensive and comprehensive water quality and quantity monitoring networks.

The SCA collects water from five catchments, with 62 percent of the catchment land privately owned, 28 percent national park, nine percent SCA freehold, and the remainder Crown land.

Activities in the catchment have potential to adversely affect water quality. Impacts can be caused by inflows of pollutants from point sources such as sewerage system discharges, and from diffuse sources such as agricultural run-off and urban development.

Responding to these risks requires a full suite of land management, regulatory, and incentive tools to affect change. These include managing the Special Areas, which are protected lands surrounding water storages, setting controls on land use planning, and devising assessment tools for new developments. It also involves rectifying existing polluting activity through various catchment improvement works including the use of regulatory mechanisms, funding works, and educating the community.

The SCA prioritises the actions it takes in the catchment to protect water quality using the process described in the following figure. 

Image of Figure 1 - Catchment Planning and Delivery System

Figure 1 - Catchment Planning and Delivery System. View larger image of Figure 1.

The Catchment Decision Support System has been used over the past 12 months to help prioritise catchment actions. Using the best science and research, it assesses water quality in the catchment based on potential pollution sources for four primary pollutants: nitrogen, phosphorous, sediments and pathogens. The catchment is mapped for the location of potential sources and key pollutants and their risk to water quality. 

Prioritising catchment programs also involves considering broader Government priorities as well as the outcomes of the catchment audit. The SCA also identifies potential partnership opportunities where it may access additional catchment resources to deliver its programs.

This strategic approach allows the SCA to deliver targeted catchment protection initiatives that provide the best water quality outcomes.

The SCA manages its own lands and works in partnership with many others to achieve its vision of ‘Healthy catchments, quality water – always’. Figure 2 shows the SCA’s current catchment programs under the Healthy Catchments Program.

Image of Figure 2 - Catchment Programs

Figure 2 - Catchment Programs. View larger image of Figure 2.

Over the past decade, the SCA has delivered key catchment management and land-use planning initiatives including the implementation of 'Sustaining the catchments – the regional plan for the drinking water catchments of Sydney and adjacent regional centres'. This planning instrument is a key tool in the ongoing management of catchment water quality. The SCA also continued to deliver on the important Accelerated Sewerage Program, which helps to reduce the risks to the water supply through the upgrade of sewage treatment plants. The SCA is spending $37.7 million on this key program. The organisation also maintains a strong focus on mining in the catchment and undertakes science and research to help determine long-term impacts.