Waterway management through sub-catchment prioritisation studies in the Hornsby Shire LGA

Rubio A1, Guise K1, Wainright M2, Dela-Cruz J3

1Hornsby Shire Council, Natural resources Branch,

2Alluvium Consulting,

3Department of Planning, Industry and Environment


Waterways in the Hornsby Shire LGA extend for 1200 km in freshwater reaches and approximately 200km in estuarine waters. Despite Hornsby Shire Council’s desire to protect and improve condition of its waterways, limitations on funding and resources make this challenging. Hornsby Council has reviewed several approaches where catchment management actions were prioritised for specific sub-catchments based on waterway use, sensitive environmental values, existing and future threats (including diffuse and point sources) and changes to land use among other components.

In particular, one of the approaches used has been the implementation of Stage 1 of the Risk-based framework for considering waterway health outcomes in strategic land use planning decisions (Dela-Cruz J, et al 2017). This NSW framework presents a structured approach that decision-makers, such as councils and environmental regulators, can use to help manage the impact of land-use activities on the health of waterways.

Critical to this work is to use a methodology that allows stepping down from a high-level basin scale (e.g. Hawkesbury- Nepean catchment) to a local sub-catchment scale (i.e. suburb or streets along a section of a waterway) with adequate resolution to implement management actions and that quantifies any improvements.

The presentation will discuss the various waterway health outcomes that can be achieved by working at different spatial scales when prioritising works in a catchment.


Ana is an environmental scientist at Hornsby Shire Council. After 20 years of research in academia working with the oyster industry decided to work in estuary management where she can combine her scientific skills with natural resources management. Ana’s current role is to develop a CMP for the Hawkesbury River System. Ana  is also involved in maintaining and responding to an extensive estuary monitoring program in the Hawkesbury that involves real-time telemetry-based water quality monitoring stations. This information feeds on a wide range of applications including predictive modelling of public health issues at recreational estuarine sites and catchment health management approaches.