Wet weather discharge FAQ

Generally, our small to medium lagoon-based sewage treatment plants are subject to an occasional wet weather discharge. The recycled water produced by these plants is used to irrigate nearby land. During periods of wet weather, holding lagoons fill-up and we can’t irrigate the surrounding saturated land.

Heavy rainfall causes high inflow into sewage treatment plants. The storage capacity of holding lagoons is exceeded and discharge into a local waterway is required to ensure that the dams do not overflow.

A wet weather discharge poses no additional risk to public safety or the waterway. Risk assessments are completed for all discharges. These assessments look at the risks associated with public health, health and safety, and the environment.

A monitoring program is carried out during the discharge to ensure there is no impact on raw water extraction for potable water supplies.

The length of a wet weather discharge is influenced by the levels of holding lagoons and rainfall. Generally a wet weather discharge will continue for several weeks. 

North East Water will cease the discharge as soon as practicable.

We notify the following stakeholders before a wet weather discharge is commenced:

• Department of Health and Human Services
• EPA Victoria
• EPA NSW (when discharged into Murray River)
• Goulburn Murray Water
• Local governments, and
• Catchment Management Authorities.

Wet weather discharges are completed in accordance with the EPA Victoria sewage treatment plant licence conditions and guidelines. 

We are required to contain all inflows to a sewage treatment plant up to a 90th percentile wet period where storage water is used for irrigation.

As the statistic suggests this means that wet weather discharges should only occur in a greater than one in ten year weather event.

To ensure we meet that requirement, the construction of additional storage is scheduled for Benalla, Chiltern and Rutherglen in the next 3-5 years.

North East Water on 1300 361 622.