Performance of the Hunter River Salinity Trading Scheme

The Scheme has proved tremendously successful and is widely supported by the community that contributed to its creation.

We administer the scheme with guidance from an operations committee with representatives of the community, industry and the government. The scheme uses a market-based instrument to successfully address a serious environmental problem.

Performance summary: 2021–22

The Hunter River Salinity Trading Scheme performed well in the 2021–22 financial year by largely maintaining electrical conductivity (EC) levels in the river within target levels during periods of industry discharge.

This was despite unprecedented high rainfall and flows in the Hunter River leading to increased salt loads carried past Singleton. The extreme wet weather also presented water storage and management challenges for industry. However, participants managed their onsite water within the regulatory framework, only discharging during available opportunities. In doing so, participants have supported the overall scheme objective, by balancing their need to discharge with the needs of agricultural water users.

We acknowledge the challenges for industry and will be reviewing the scheme to ensure its continuing effectiveness in extreme weather events.

2021–22 performance report

The map below identifies the locations of each sector of the Hunter River referred to in the Scheme.

Hunter Valley map

Previous performance reports

Each year we assess and report on the performance of the scheme.

Longer-term scheme performance

While the scheme operates to manage salinity levels in the river as a result of industry discharge, occasional exceedances still occur, caused by diffuse sources of saline runoff. New mines can readily be granted discharge licences, with significant economic and employment benefits for the valley.

However, since the scheme started, river salinity has more consistently been below the salinity target.

These improvements have occurred since higher average rainfall has occurred after the scheme began, granting scheme participants more discharge opportunities and maintaining salinity targets.

The graph below shows that in previous dry spells (in the early 1980s and 1990s) average salinity levels were very high. These have not been repeated during the time since the scheme commenced.

Monthly Average Electrical Conductivity at Singleton 1980 to 2002


The graph below shows the yearly average electrical conductivity at Singleton between 1993 to 2022. It shows that the average EC was higher in the period before the commencement of the Regulation in 2002 while average EC has stayed well below the target since the commencement of the Regulation.

Chart showing Annual Average Electrical conductivity at Singleton 1993 to 2022