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Previous updates - Jan to June 2017

Previous updates - Jan to June 2017

Updated 8 January 2018 9:43am

Latest News - 23 May 2017

The landfill operator and their consultant have prepared a construction programme for the completion of the already commenced stormwater solution over the next 7 months. The programme of works has been reviewed by GWRC to ensure that it reflects the urgency with which the works are required to be completed and that the works will not create downstream flooding effects. GWRC’s reviewer has confirmed that the construction programme is appropriate and reasonable. The construction programme timetable and a more detailed staging plan are available on this page. The construction of the stormwater diversions is a substantial undertaking and requires the construction of two dams in the headwater streams (to ensure that downstream flooding effects are not exacerbated). All works on the stormwater diversion system are scheduled to be completed by the end of December 2017. Completion of the different stages of work will be as follows:

  • Completion of bottom swale to outlet into the stream by mid-June 2017
  • Completion of eastern swale by end September 2017
  • Completion of eastern dam by mid October 2017
  • Completion of western swale by end October 2017
  • Completion of western dam by end December 2017

GWRC will be meeting with the landfill operator and their consultant on site at least once a month to check progress of the works against the programme of works. We will continue to keep you updated as the works progress.

Latest News - 18 May 2017

There is discolouration in the Owhiro Stream and a sediment plume in Owhiro Bay from rain in the last 24 hours. This rain has mobilised sediment which has been disturbed during the construction of the stormwater diversion channels at T&T landfill. We have been on site and are working with the landfill operators and their contractors and consultants to ensure that erosion and sediment control measures are in place to minimise the release of sediment into the stream. A discharge of sediment from the site during the early phase of construction was expected as there are limited options to manage the release of sediment from within the diversion channels themselves. We expect the release of sediment from the site to continue to decrease as the works progress and as additional sediment treatment measures are put in place.

Latest News - 10 May 2017

Further information on GWRC enforcement decision

We have been asked for some clarification on the enforcement decision for the November/December discharge from T and T Landfill.

Three infringement notices were issued to T and T Landfills Limited who operate the site.  These were for each of the occasions that officers visited the site as a response to public notifications during the November/December discharge.

An infringement notice is issued where there is a breach of the Resource Management Act (RMA) serious enough to warrant punitive action but not so serious as to require laying charges.  They may be issued for each offence that we have evidence for and to each offender involved. 

Offences under the RMA are criminal offences and the level of proof required is “beyond reasonable doubt” for each offence.

The decision on the punitive outcomes was made by a panel which included, team leaders, managers, investigating officers, and compliance and consents officers.  Some of the important factors considered in this case were:

  • Level of environmental effect – this is specific to this incident and does not relate to the ongoing, background effects of the discharge (the recently published ecological report was a key source of information for this discussion)
  • Nature of the receiving environment – this included discussion around the value of the Owhiro Stream to the community
  • Mitigation and aggravation – this included discussion around the historic nature of the landfill underneath the current landfill, the circumstances under which the consent was granted, the steps taken to remedy or mitigate (both before and after this incident)
  • The “level of criminality” was also discussed
  • Consistency with other previous cases
  • How punitive action will affect Environmental Outcomes

By weighing up these various factors we came to the decision to issue the infringement notices.

NB – we also recovered the cost of our investigation from T and T Landfills. 

For further information on our investigation and enforcement process, please see -

Environmental outcomes

Alongside the punitive outcomes our focus has been on how we will work with the landfill operator to make changes onsite to reduce the adverse effects of the discharge by 'fast tracking' mitigation measures such as the wetland and clean water diversion construction. We are asking whether the consent conditions are ‘fit for purpose’ to address the peaks and ongoing discharge and looking closely at ongoing water quality monitoring results. These will be used to determine whether the mitigation measures being taken are effective or further adaptive management changes are required on the site.

There will be further updates on the ongoing actions in the coming weeks.

Responses to ideas and questions raised at the Community Information Day

A number of questions and ideas were put forward by the community during the Information Day held on the 25th March. We have put together some information and responses to these which can be viewed on the ‘relevant documents’ list on this page.

Latest News - 02 May 2017

The full ecological report commissioned by GWRC on the November 2016 incident has now been made available here. This provides further detail in relation to the key findings as per previous update. 

Latest News - 27 April 2017

Sample results from April 2017 incident

Since 6th April there has been discolouration, high flows and foam in the Owhiro Stream as a result of the ongoing discharge from T&T Landfill. GWRC took water quality samples on the 10th April and have received the sample results. As with previous incidents, the sample results indicate that the concentrations of contaminants in the landfill tributary increased as a result of the passage of water through the landfill. This is likely to have resulted in chronic and acute toxicity effects on aquatic life during this period. These results, while disappointing, were expected as the stormwater diversion channels are still under construction. This is why GWRC compliance focus is working with the landfill to get the diversion works done as quickly as possible. More on this below.

Ecological report

The ecological report commissioned by GWRC on the November 2016 incident has been finalised and will be released shortly. The assessment provided in this report was used to inform the enforcement decision which was made in relation to the incident late last year. The report will be available in the ‘relevant documents’ list on this page.

Key findings from the report are:

  • Long term monitoring data indicates that the discharges from T and T Landfill cause a number of significant adverse changes in water quality and ecology
  • “Spikes” in contaminant concentrations in the discharge have been measured, leading to effects greater than the ongoing discharge
  • The mitigation measures, diversion of stormwater and implementation of a treatment wetland are needed urgently to mitigate the effects of the discharge

Onsite construction works on mitigation measures

The work to install the stormwater diversion channels is well underway and we have been onsite.


The landfill operator has also installed a pump to pump clean water from the Mitchell Street gully into the diversion channels. Pumping has occurred over the last few days and the gully is now empty of water  - this was critical work as it reduced the amount of water that could have filtered through the fill material and would have drawn out more leachate if it was left to drain through the landfill. The pumping out caused some discolouration of the stream, but this was seen as a necessary step to reduce the overall impact on the stream.

We have received a more detailed works programme from the landfills engineer and this currently being reviewed by GWRC independent engineering consultant to ensure that it demonstrates the urgency which mitigation measures need to be put in place as expressed by the landfill and GWRC ecologists. Once finalised, the works programme will be made available on this site. The construction of the stormwater diversion channels remains a priority as this will see the contamination levels in the stream reduces significantly.

Latest News - 11 April 2017

Over the past 48hrs, GWRC have received five notifications of discolouration and foam in the Owhiro Stream. This has been linked back to T and T Landfill and the discharge appears similar to that from November/December 2016.  This discharge has been linked to the recent high rainfall and an increase in water flowing through the fill.  A GWRC officer attended the site yesterday to investigate and sample.

The work to install mitigation measures required under T and T Landfills consent, to reduce the effects of discharges, is ongoing. 

T and T have informed us they have an engineer on site today to look at ways to reduce the current high flows through the landfill.  GWRC are continuing to work with T and T to ensure the effects on the Owhiro Stream are minimised.

As in the previous incident, we are in contact with Regional Public Health. Whilst we do not envisage any human health impacts, we would like to take this opportunity to reiterate best practice advice around staying healthy around recreational water and home gardening as per our update on 08 December 2016

Please see the FAQ’s and Previous Updates for further information.

Latest News - 23 March 2017

GWRC's investigation concluded

GWRC’s investigation into the T&T Landfill discharge incidents in November and December 2016 has concluded that the landfill breached its resource consent conditions and the Resource Management Act 1991 (RMA). The action we have taken is as follows:

  • T&T have been issued with 3 infringement notices for specific breaches
  • A formal warning has been issued to the director of the T&T Company 
  • Advice letter confirming a breach of the consent and RMA have been sent to the consultants to T&T landfills
  • Advice letter confirming a breach of the consent and RMA have been sent Wellington City Council (as they own part of the land the site operates from)

Our focus since the incident has been working with the landfill operator to make changes onsite to reduce the likelihood of reoccurrence of an incident like this happening again by 'fast tracking' mitigation measures such as the wetland and clean water diversion construction. The landfill has been co-operating fully with GWRC in putting these measures in place, and appreciates the urgency of the situation, and the impact its site had on this occasion to the stream and the community of Owhiro Bay.

Compliance programme changes following the conclusion of the investigation

In addition to the work we have been doing with the landfill operator, GWRC’s compliance programme over the next few months will focus in on whether the consent conditions are 'fit for purpose'. This is common practice after an incident of this nature, and an important step in the regulatory process.

We will also be looking closely at ongoing water quality monitoring and ecological survey results which will tell us how the stream is recovering following the incident. This monitoring information and the ecological reports from the incident will be used to determine whether further adaptive management changes are required on the site.

Latest News - 16 March 2017

Ecological Assessment of Owhiro Stream released 

Following the unconsented discharge into the stream from T and T Landfill late last year, the ‘adaptive management’ provisions of the resource consent were set in motion. Adaptive Management is a tool used in consents where environmental monitoring shows there is a need to adjust the management of a site or issue.
Water quality monitoring following the discharge showed a breach of the consent conditions and this meant the operator had to undertake an ecological assessment of the stream.

The discharge discoloured the stream and left an orange residue on the stream bed. The ecological assessment gives us an understanding of how the discharge has affected the stream environment. 

What the assessment says

The ecological assessment shows a rising trend in some contaminants in the tributary downstream of the landfill, particularly ammonia, iron and manganese. It goes on to state that these contaminants have had a significant adverse effect on invertebrates (insects, snails, etc.) in the landfill tributary. The contaminants had a lesser but still measureable effect on invertebrates in the Owhiro Stream immediately downstream of the confluence.

The effects of the discharge require mitigation.

What the landfill needs to do now

The report says the priority should be diverting streams around the landfill, including the minor side gullies and the two main branches of the landfill tributary. Diverting the streams and local stormwater around the landfill will reduce the amount of contaminants entering the stream. This will enable any remaining contaminants to be more effectively treated by the wetland at the toe of the landfill.

GWRC has advised the consent holder to complete the construction of the wetland at the toe of the landfill including wetland planting. The wetland construction is complete and planting has started. GWRC has advised the consent holder to begin diverting the streams and stormwater around the landfill to reduce the amount of water flowing through the landfill, and work is underway. Given the conclusions of the report, GWRC is also having discussions with T and T Landfill about changes to the proposed work programme and further mitigation. 

The incident investigation

The incident, that occurred prior to Christmas, is still under investigation. GWRC has received a formal response from the landfill and is assessing all available evidence.  An enforcement decision will be made prior to 22 May 2017.

Latest news – 03 March 2017

Wetland works

Further shaping and planting of the wetland has been happening this week. GWRC will complete a compliance inspection of these works in the week beginning 6th March 2017.

Stormwater diversion works

Works to cut a diversion channel to take cleanwater out of the wetland have commenced – see photo.

Change of conditions consent application

GWRC is working its way through further information submitted by the landfill and clarifying some further points with them.

Ecology report

The landfill was required to undertake an ecological assessment of the Owhiro Stream, as required by the adaptive management conditions of their consent. GWRC have received this, and are considering its findings at present. 

Latest news – 7 February 2017 

Wetland works

GWRC undertook a compliance inspection on 2 February 2017 to inspect the works on the wetland. The wetland is to be located at the toe of the landfill and will provide some attenuation and pre-treatment of the discharge prior to it entering the tributary of the Owhiro Stream below the landfill. T&T landfills have commenced construction of a wetland and it is likely to be complete within the next few weeks.


Wetland construction on 02 Feb 2017

Change of conditions application

T&T landfills have obtained the written approval of Wellington City Council on the change of conditions application which will allow them to construct stormwater diversions via open swales around the landfill. GWRC is currently waiting for further information on the application before processing of the application can be completed. 

Latest news – 19 January 2017 

Further sampling and testing

Another round of water quality sampling was undertaken by GWRC officers on 18 January 2017.  The results from this will be analysed, with the other samples, to look at whether levels of contaminants have fallen since before Christmas and what this means for environmental impacts on the stream.

Latest news – 09 January 2017 

Further sampling and testing

4 lots of water quality sampling have now been completed in the Owhiro Stream in the 4 weeks leading up to 22 December 2016.  GWRC have also engaged an ecologist who, along with GWRC Environmental Scientists, is carrying out an assessment of the effects on the aquatic life.

This sampling and assessment of effects is in addition to the monitoring that T and T Landfill are required to carry out under their consent.

New links added to webpage

Following the community meeting on the 15 December 2016, we have added some useful links and documents to the right hand side of this webpage.

One of these links is Greater Wellington Regional Council’s mapping page for Recreational Water Quality. Information specific to Owhiro Bay can be accessed by:

  • Choosing ‘Select a local area’
  • Selecting ‘Wellington’ from the drop down menu
  • Selecting ‘Owhiro Bay’ from the list of sites provided.

Please note that the test results referred to on this page are part of the weekly water quality monitoring done by Wellington’s regional, city and district councils during the official summer swimming season (December to March), and does not relate to the further sampling and testing mentioned above. The safety of water for swimming is determined by measuring ‘faecal indicator bacteria’ (enterococci in coastal waters and E. coli in rivers) which indicate likely levels of pathogens in the water. Results are then compared to national guidelines. You can also use this page to access water quality information for a range of other sites in the Wellington Region. 

Updates prior to January 2017