Short term approach for managing wastewater discharge

As of Monday 31 March, 2025, fully treated wastewater will be diverted from the disposal field and discharged directly into the Shotover River, using a historic channel north of the facility that was used for discharge prior to 2019 (in line with QLDC’s resource consent at that time).  The indicative location of the discharge channel is shown below:

To ensure appropriate mixing of treated wastewater with river water, regular work in the Shotover River is also anticipated to maintain a flowing braid near the discharge point.

Under the RMA QLDC will need to apply for resource consents from ORC for the ongoing effects of the works.

QLDC is therefore seeking short-term consent(s) for this disposal method, which would be expected to expire on or before 31 December 2030 (when the long-term disposal option is operational).

A wide range of options to try and resolve the effects of ponding at, and from, the disposal field have been considered, including:

• Gravel filling areas to the south of the disposal field to remove ponding and prevent human contact.

•  Expansion of the existing field.

• A combination of options which would retain the current disposal field but utilise a direct discharge for volumes beyond the field’s capacity.

• Bird netting to prevent birds settling on the areas of ponded water.

All of the options noted above would require new or additional resource consents from ORC and come with their own adverse effects.  QLDC has also investigated trying to repair the disposal field and providing buffer storage within the treatment ponds to try and minimise spillage from the field.
None of these options are considered suitable to address the core issues and manage the identified risks in a suitable timeframe. 

Yes.  Under the RMA QLDC will need to apply for resource consents from ORC for the ongoing adverse effects of the works.  QLDC will therefore seek short-term consent(s) for this disposal method, which would be expected to expire on or before 31 December 2030 (when the long-term disposal option is operational).

While a short-term discharge of treated water into the Shotover River is not an easy decision to make, in this situation QLDC is confident it is the most responsible option that can quickly and conclusively address the risks discussed above, particularly the risk to aviation safety.

However, it is useful to understand that given the proximity of the existing disposal location to the Shotover and Kawarau rivers, the current facility’s treatment processes are already designed to produce a quality of treated water appropriate for the receiving environment (in this case the Shotover River and Kawarau River). As such, the community can have confidence the action will not result in a degradation of the environment.

Discharge to water is common in Aotearoa New Zealand, with over 200 treatment facilities across the country discharging to water currently. 

Historically, the Shotover WWTP has performed effectively and consistently achieves compliance with the quality standards set out in its resource consent for treating wastewater at the point of discharge.   Historical monitoring of the previous river discharge did not identify any significant in-river water quality and ecological adverse effects after reasonable mixing with the river flow.

The discharge, while larger than occurred in the past, will be of a better quality and, from the end of this year, 100% processed through the MLE plants (achieving an even higher overall standard).

QLDC acknowledges that there have been two instances in recent times where the treatment plant experienced failures which resulted in the discharge of partially treated wastewater. In the wake of these incidents QLDC and its operations contractor have been reviewing practices and contingency arrangements to make the treatment plant’s operation as robust as possible. These events occurred in December 2023 and July 2024 and were reported to ORC at the earliest opportunity.

As outlined above, the plant’s operations are monitored closely and QLDC will be supplying an increased frequency of monitoring results to the ORC in response to this change in situation.

Click below for sampling results from Shotover WWTP, dating back to 2018.

Further monitoring data will be published here when it becomes available.  

Currently the treatment plant processes around 12,000m3 of wastewater per day.

This represents less than 2% of the flow in the Shotover River and less than 0.2% of the flow in the Kawarau River (in low flow conditions).

To put this in context, a volume in excess of the total daily volume of water processed through the treatment plant passes through the Kawarau River every 3 minutes.

Yes, the standard of treatment achieves the quality required for contact recreation such as swimming and with suitable mixing in the river flows poses no risk to human health. 

QLDC will be completing extensive in river monitoring to ensure effects on the environment are understood and to enable action to be taken should anything unexpected be observed. 

No, the standard of treatment and degree of mixing/dilution will mean that there will be no impact to the downstream water quality.   

Yes.  QLDC has engaged directly with representatives of Aukaha and Te Ao Mārama and acknowledges the significance of the change in disposal method from an iwi perspective.

QLDC places significant value in its relationships with local iwi and remains committed to working alongside our iwi partner representatives Aukaha and Te Ao Mārama through the selection of the long-term disposal solution. 

Bird strike is an issue globally for all airports and Queenstown Airport Corporation has a comprehensive wildlife management plan, particularly focused on birds. QAC uses a range of tactics to manage the risks associated with birds and bird strike, including bird-scaring, such as light flashes and sound to disperse and deter birds. Before each flight, the airport emergency services team completes airfield checks.  

However, QLDC has been notified by QAC of increased waterfowl activity around the ponded field which poses an elevated risk to aircraft operations in the area (including being close to/under the main flight path). In the January 2025 survey, it was observed that 252 birds had taken up residence on the disposal field.  QAC considers that QLDC needs to take urgent action to reduce the risk of bird strike.

The temporary discharge solution will allow the disposal field to drain completely, removing the ponded areas from the site, stopping any discharge from the disposal field, and in doing so entirely removing the new standing water which is attracting waterfowl to the area. 

No, this is not required.  Shotover WWTP continues to produce highly treated wastewater, and the current challenges with the disposal field are not adversely affecting the final receiving environment of the treated water (namely the Shotover and Kawarau rivers).

It’s important to highlight that there has been considerable investment in this treatment facility over the past decade, with upgrades resulting in significant improvements to the quality of the treated water whilst also providing for the capacity to meet the growth demands of the Whakatipu basin.

Right now, work is underway on the construction of a second process treatment train at the plant. Once complete (by the end of this year) this investment will allow the oxidation ponds on site to be fully retired and will achieve a further improvement in the quality of the treated water produced by the plant.  

QLDC is committed to working with ORC and iwi to develop a more robust long-term approach for the disposal of treated wastewater from this facility. QLDC believes the scale of investment prioritised through the current Long Term Plan ($77.5M) speaks to this commitment.

Halting development in the short term will have an extremely limited impact on the flows entering the treatment plant and as such the volume requiring disposal. This is an issue affecting the community today, but one that requires a solution that will endure into the future. It is important to recognise that the development community will play a pivotal role in helping to fund the long-term disposal approach. 

The disposal mechanism can be changed over for next to no cost. However, QLDC is planning some subsequent work to clear vegetation and improve the channel. This work has not yet been costed, but the costs involved will be minor.  Ongoing environmental monitoring costs, and the costs of obtaining consent for the ongoing adverse effects (including potential mitigations) will also be incurred.