How the Hunter River Salinity Trading Scheme works

Salty water is only discharged when there is a lot of low salt, fresh water in the river. Every 2 years, a credit auction is conducted, where people can trade their salt discharge credits. People can only discharge the amount that their credits allow.

The Scheme involves a finite system of 1,000 salt credits that participants can buy and trade, allowing them to discharge their saline water into the Hunter River at times identified by the Service Coordinator, WaterNSW. WaterNSW operates and maintains a series of water flow and quality monitoring gauges along the river, providing real-time data which is then used to identify discharge opportunities.

Discharge opportunities are identified to the participants by publication of river registers. These are a notification published by WaterNSW when the flow in a particular sector of the river is high enough to allow discharge of saline water without going over the target EC for that sector. Each published river register includes a Total Allowable Discharge (TAD – referring to tonnes of salt) number which, together with their number of discharge credits, guides participants as to what they can discharge.

For the purposes of the Scheme, the river is divided into 3 sectors (Figure 1), with sector specific salinity targets. Flow conditions dictate when a river register is issued and hence discharge is permitted. These salinity targets and flow conditions are set out in the Protection of the Environment Operations (Hunter River Salinity Trading Scheme) Regulation 2002. In summary, when the river is in:

• Low flow, no discharges are permitted
• High flow, participants can discharge quantities based on the number of credits they hold
• Flood flow, participants can discharge freely irrespective of the salt credits they hold, if the salinity targets are not exceeded; this is monitored by WaterNSW.

Figure 1: Map of Hunter River sectors