Mapping outflow events

This project maps the extent and impacts of coastal outflows on marine ecosystems.

What are coastal outflows?

Coastal outflows are the plumes of fresh water that flow from rivers into the sea.

When scientists know these three things, they can better understand how outflows affect water quality along the open coast and if the quality is changing. They can also understand how the outflows may impact offshore reefs.

This will help us make better decisions about what we can do to manage the impacts of coastal outflows.

What have we achieved so far?

Entered the final season of sampling for our collaboration with CSIRO in Bega, Shoalhaven and Macleay. This project focuses on measuring coastal outflows to help scientists understand their positive and negative impacts, particularly on water quality along offshore reefs and the open coast.

The goal is to determine if water quality is changing over time, allowing us to make better informed decisions for managing the impacts of coastal outflows.

Sensor stations have been installed at the Iluka breakwater entrance to Clarence River and the breakwall at the Entrance in Tuggerah, which includes hydraspectral sensors that will calibrate satellite based remote sensing.

This setup will provide higher temporal and spatial resolution of real-time water quality information, contributing to improved monitoring for estuarine and coastal management as well as extreme event response.

The data these sensor stations collect, will enhance satellite derived water quality algorithms, which are essential for monitoring and prediction tools.

Published a co-written paper titled Mapping total suspended solids (TSS) and dissolved organic carbon (DOC) in complex coastal waters using deep learning enhanced remote sensing in scientific journal, Ecological Informatics.

Through our collaboration with CSIRO, we completed a major field campaign and developed an in-water bio-optics library for 9 estuaries across the NSW Marine Estate. This dataset captures the optical characteristics of diverse water types and forms a critical foundation for remote-sensing models and future monitoring programs.

We also delivered a decadal, statewide deep learning model built from the Spectral Library collected between 2022 and 2025. This model gives us a clear picture of water quality across NSW, extending into southern Queensland, northern Victoria and Lord Howe Island.

We contributed to a series of peer reviewed papers that advanced understanding of coastal water quality and ecosystem responses.

We shared Coastal Outflows project findings across several scientific forums, including national conferences, technical hubs and community seminars.

Presentations highlighted emerging insights into coastal water quality and advancements in monitoring and modelling. A project briefing outlined key achievements and demonstrated how new tools are improving understanding of coastal processes.

Pesticide risk exposure metric study brings together the Ecotoxicology team within the Environmental Protection Science Branch, Ballina Shire Council, Shoalhaven Council and the Port Authority of NSW and University of Queensland. It trials a Queensland based pesticide risk assessment metric measuring pesticide exposure and delivery from 4 key NSW estuarine catchments (Hunter, Shoalhaven, Clarence, Richmond) to coastal waters.

The project aims to record a timeseries of seasonal concentrations as measured at the entrance surface waters of these systems.

The two real-time water quality sensor stations deployed at Iluka, near the mouth of the Clarence River, and in Tuggerah Lakes on the Central Coast use state-of-the-art monitoring equipment, including a CSIRO Hydraspectra sensor that records surface reflectance every 10–15 minutes, 24 hours a day. Each station also includes a Xylem EXO system that measures water quality parameters at 4 depths through the water column.

For more information about our achievements in Marine Estate Management Strategy, please visit our report page.