ORC has been regularly undertaking testing to monitor compliance with consented limits and conditions. This occurred at a standard series of locations to enable trend data to be collected. Testing included investigation of E. coli – Escherichia coli, TBOD – Total Biochemical Oxygen Demand, TN – Total Nitrogen, and TSS – Total Suspended Solids.

The samples were analysed based on consents parameters, and, where appropriate, other parameters used to detect wastewater. Sampling is completed by ORC staff in line with sampling procedures and analysed in an independent lab.  

From 7 April 2025 a new set of standardised sampling locations were set up to specifically monitor the discharge on site. You can find out more about this monitoring programme in the sections above. These sites were sampled weekly until 11 August and they are now sampled monthly along with a site inspection. 

From August, ORC will be doing monthly testing  on site to monitor compliance with consented limits and conditions and the Enforcement Order rather than weekly. This will happen at the  standard series of locations to enable trend data to continue to be collected. Testing included investigation of E. coli – Escherichia coli, TBOD – Total Biochemical Oxygen Demand, TN – Total Nitrogen, and TSS – Total Suspended Solids. The samples are  analysed based on consents parameters, and, where appropriate, other parameters used to detect wastewater. Sampling is completed by ORC staff in line with sampling procedures and analysed in an independent lab. 

Under the Enforcement Order, QLDC is required to undertake monitoring on site. ORC will audit this monitoring and the results regularly to ensure that they are compliant and to check for any impacts on waterways. These results will continue to be supplied on this webpage.

ORC will continue to monitor the Kawarau River at Chard Road State of the Environment Monitoring site once a week to ensure the community has access to frequent monitoring results and to continue to provide information to downstream water users. 

Yes, ORC has been undertaking inspections to monitor the site and monitoring the results of sampling undertaken.

Now that the Enforcement Order is in place as well as the monitoring required under the resource consent  QLDC are  now required to undertake a wide range of monitoring and supply these results to Council.  Staff have reviewed what QLDC are required to do under their Enforcement Order; what the results of our monitoring programme to date have shown and balanced this against the continued need to provide information and confidence to the public. With this in the mind the monitoring for the site has changed to monthly compliance sampling on site and the continuation of weekly monitoring of the Kawarau river at Chard Road will continue. 

 The approach to monitoring will be looked at again once any decision is reach on the consent; if there are impacts on the environment or upgrades are made on site.  

You can download the result sheets from the testing sample results above.

On 31^st March, samples were taken from the discharge channel itself and upstream and downstream in the Shotover River. These samples showed E. coli levels of 730 CFU (colony-forming units) per 100 mL of water in the discharge channel and 370 CFU/100 mL at the downstream location. 
  
These higher E. coli results are not a reliable indication of the treatment performance of the Shotover WWTP, as they were taken after the discharge left the treatment process and were likely affected by the first flush of any natural materials in the channel, such as rabbit droppings and decaying vegetation. 
  
The sampling round conducted on 7^th April 2025 was more extensive and included the final discharge at the official sampling point downstream of the UV tertiary treatment stage as well as the discharge channel and other upstream and downstream locations (refer official map). The Shotover final effluent (IN25.0273B) sampled at the official point post-UV was fully compliant with the consent limit of 260 CFU/100 mL, showing an extremely low result of less than 1 CFU/100 mL. The sample taken in the discharge channel 7^th April 2025 showed E. coli was 4 CFU/100 mL. For comparison, in New Zealand, the drinking water standard for E. coli is less than 1 CFU/100 mL.

The discharge to the Shotover is being undertaken via Emergency Works provisions provided under s330 of the RMA.  The decision to use this power, was made by QLDC. Any questions on this must be directed to QLDC.  

This means that there is not currently a consent or application in place for this activity with specific limits. Subject to affects being ongoing, QLDC must apply for one within 20 working days of notifying ORC of emergency works.    

When a consent application is received that relates to the emergency works, or any other short-term application for the site then ORC will know more about how the discharge will be managed. If and when an application is received and accepted for processing by ORC, a notification assessment will be undertaken to determine whether the application can be processed on a non-notified basis, or whether it should be limited notified or proceed with full public notification.   

Any QLDC application for retrospective consent, or consents around SWTP operations will be viewable online shortly after it's lodged with ORC. ORC will not comment on an application while it is being assessed. 

Once the application is online this does not mean it is open for submissions or feedback – it will be online for information and awareness.  Any decision on public notification and submissions will be made in line with the RMA. 

The timeline to process an application depends on whether additional information is required and whether the application is notified or non-notified.

Questions been raised about the impact of the discharge on the Shotover and Kawarau Rivers and what role dilution plays.

We can compare the volume and contaminant concentrations of the treatment plant discharge with the flow in the rivers to better understand the impacts.

One way to assess the impact of an activity on a river is to look when the flow is lowest, and the river is most vulnerable to impacts. A common way to do this is by calculating the average flow of a river during the lowest 7 days of the year. In the Shotover River this 7-day low flow is approximately 14 m³/s or 14 ‘cumecs’.

Per the discharge consent, ‘the volume of wastewater discharge shall not exceed an annual average of 11,238 m³/day’. This equates to an average flow of 0.130 m³/s, or 130 Litres per second. The ratio or ‘dilution factor’ between the plant discharge and the river flow can be determined from this equation:

Using this equation shows the average rate of discharge from the plant will be ~108 times less than the flow of the Shotover River, assuming the river is at its lowest flow rate. Most of the year the river will have a higher flow than 14 m³/s, and the proportion of plant discharge flow compared to the Shotover flow will be less.

By comparison, the Kawarau River, as measured downstream from the Shotover confluence, has a much higher 7-day low flow of 89 m³/s. Consequently, the rate of discharge from the treatment plant will be ~680 times less than the flow of the Kawarau River in low flow conditions. Most of the year when the rivers have a higher flow rate, this proportion will be less again.

The Shotover and Kawarau Rivers have important roles in diluting the discharge from the treatment plant. Any contaminant loads in the treated effluent, such as E. Coli or nitrogen, will be mixed and diluted in the larger rivers. In the Shotover they will be diluted by a factor of at least 108, and in the Kawarau the rate of dilution is likely to exceed 680. 

Any decision on if this discharge is appropriate and on effects moving forward will be assessed through any consents and compliance processes.

The process to apply for the enforcement order, including expert advice, laboratory costs, lawyers, staff time, vehicle and monitoring of the site cost ORC $274,047.50 (GST exclusive) (excluding mediation costs). Through the Enforcement Order process, QLDC has paid ORC a contribution of $235,000 (GST exclusive).

The cost of responding to incidents on site was $25,209.00 (GST exclusive)

The cost of monitoring consent compliance on site was $17,107 (GST exclusive)

The Order requires QLDC to take specific actions to avoid, remedy and/or mitigate effects on the environment by specific dates relating to:

• Amendments to the Operations and Management Plan
• Training
• Sampling and monitoring
• Repairs and improvements to the WWTP
• Upgrades to the MLE Plant and other parts of the system
• The Disposal field

ORC staff will monitor compliance with the requirements of the order as well the resource consent.

ORC would consider any non-compliance in accordance with its Resource Management Act Compliance and Enforcement Policy.

QLDC are required to undertake the following monitoring:

• Collect weekly samples and have these samples analysed at an accredited laboratory for various elements that could indicate that the plant is not fully functional. These sample results must be supplied to ORC. In the event of a sample exceeding the consented limits, more frequent sampling is required.
• Provide ORC with an investigation and monitoring plan for the purpose of monitoring the effects of non-compliance. This plan will include groundwater, surface water quality and ecology monitoring appropriate to the nature of the discharge. That plan must be implemented.
• If the disposal field is being used, undertake a visual inspection of the bund on a monthly basis and provide a record of those inspections to the ORC.
• If the DAD Disposal field is operational as at 5 May 2025, commence measuring the volume of treated wastewater overflowing from the Disposal Field and the water level in the Disposal Field for a period of 3 months or until the DAD disposal area is no longer used (whichever is the later).
• The Operations and Maintenance Manual is to be amended to include:
  • the monitoring of trends in the aeration manifold pressure.
  • the monitoring of turbidity levels at the outlet of the combined wastewater streams.