Landfill - background information
Rotorua’s district landfill was established in 1970.
Today the former open face tip is capped and sealed and operates as a refuse transfer station and recycling collection facility. This followed significant investment by Rotorua Lakes Council to make improvements to better protect our environment and public health and safety.
The decision to transition to a refuse transfer station and collection facility was made in 2016 in recognition of historic legacy issues associated with the open face facility.
Today the landfill is well managed by Council’s contracted operator Waste Management, which has implemented many improvements on Council’s behalf.
Rotorua Lakes Council’s Waste Strategy, which was adopted in 2016, sets out detail of steps taken to address landfill legacy issues and protect the facility and surrounding environment.
In early 2017, with work to cap and seal the landfill underway but not yet completed, a series of severe weather events caused saturation of the landill site and on 6 April 2017 there was further significant rain.
Stormwater mixed with leachate (a by-product of waste breakdown), breached the leachate disposal system and flowed onto land within the landfill site.
The amount of rainfall in the 30 days prior to 6 April 2017 was described by experts as the equivalent of a one-in-200-year event. It was the heaviest period of rainfall on record in the Whakarewarewa catchment and additional significant rainfall on 6 April 2017 was more than the landfill system was capable of handling.
The rainfall on 6 April 2017 caused surface flooding and multiple slips and treefalls across the Rotorua district and Bay of Plenty region, closing roads. The rain event also caused the flooding of Edgecumbe.
The effect of the breach on the receiving environment is not known but as a result of the leachate breach at the Rotorua landfill site, Bay of Plenty Regional Council brought six charges against Rotorua Lakes Council under the Resource Management Act.
Four of these (relating to green waste) were subsequently dismissed by the courts and a fifth was withdrawn by the Crown after Rotorua Lakes Council agreed to plead guilty to the remaining charge of breaching resource consent by discharging stormwater contaminated with leachate onto land in circumstances where it may enter a waterway.
While there was no evidence of adverse environmental impact in waterways as a result of the leachate breach, Rotorua Lakes Council has acknowledged the incident and extended an apology, without reservation, to mana whenua. Council accepted that it failed to meet its own expectations and that it let mana whenua and its neighbours down in this respect.
Capping and sealing of the landfill was completed in 2018.
History of Rotorua Landfill:
- The landfill was established in 1970 as an open-face landfill. The original landfill was in 3 stages, with further stages added over time.
- In 1997, Stage 1 was closed and Stage 6 opened.
- Between 2008 and 2014, BOPRC issued a number of abatement or improvement notices to Council. The leachate system was re-engineered in an effort to address the issues.
- In September 2015, Council commissioned landfill experts Tonkin & Taylor to provide comprehensive engineering advice on the state of the current landfill and options for mitigation.
- Following this advice, in early 2016, the Council committed to significant investment to transition from an open face landfill to a capped and sealed facility and the construction of a waste transfer station.
- To give effect to that decision, in July 2016 the council contracted Waste Management to carry out the construction work and manage the day-to-day operations at the facility. While the facility is managed by a contractor, as the consent holder, RLC retains primarily responsible for what occurs at the site.
- Work towards capping and sealing the site was underway in 2017 and was completed in 2018.
- The work to cap and seal the historic landfill was completed in 2018 and today, the facility operates as a waste transfer station.
- Rotorua district’s waste is transported to Tirohia, which has a facility that meets modern standards.
Frequently asked questions
30 days of rain accumulation meant the landfill site was already fully saturated when the extreme weather event of 6 April 2017 occurred and caused a leachate overflow. This was the weather event that caused the flooding of Edgecumbe as well as surface flooding and multiple treefalls and slips across the Rotorua District and wider Bay of Plenty.
Some leachate overflowed onto land at the Rotorua landfill, instead of going through the installed wastewater system.
The level of rainfall that occurred was well above the expected design capacity of the landfill’s stormwater management system and led to some stormwater that was partially contaminated with leachate to break through and flow to land. It had the potential to find its way into the Tūreporepo stream, although there is no evidence of adverse effects in the stream.
Capping and sealing of the former open tip face was completed in 2018. Work towards this was already underway at the time of the April 2017 incident.
Bay of Plenty Regional Council (BOPRC) laid six charges against Rotorua Lakes Council (RLC), each carrying a maximum fine of $600,000 – a potential total liability of $3.6million.
The challenge against four charges relating to green waste was of a technical nature and ultimately resulted in two being dismissed by the Court of Appeal and two being withdrawn.
RLC defended the other two charges on the basis of mitigating factors including that the landfill was already in the process of being capped and sealed – which was known to BOPRC – and that the severe weather experienced prior to and on 6 April 2017 was well out of its control and beyond the landfill’s capacity.
On that basis, RLC considered the charges unreasonable and the potential penalties to be a significant cost liability for ratepayers.
Ultimately, the Crown withdrew one remaining charge when RLC agreed to plead guilty to one count to bring the matter to a close.
RLC has to date incurred $480,463 in legal costs and $215,193 in technical engineering advice.
The Council is the owner of the site and the consent holder for the site and remains primarily responsible for consent compliance.
The length of time reflects the legal and technical complexities of the case. The case included a procedural decision that was appealed to the High Court and Court of Appeal, before progressing to the Environment Court for decision.
A restorative justice process was also undertaken prior to the sentencing hearing which occurred over two days in October 2021. (see HERE on RLC’s website)
Environment Judge Jeff Smith reserved his decision at that time and delivered his decision on 19 November 2021.
RLC has made significant investment into the landfill to ensure the protection of the environment, and public health and safety.
The work to cap and seal the historic landfill was completed in 2018.
There was no evidence of adverse environmental effects . However, the incident has been acknowledged by Council and an apology has been extended, without reservation, to mana whenua. Council accepts that it failed to meet its own expectations during the landfill transition and that it let down mana whenua and its neighbours.
The facility has been capped, sealed and grassed.
A leachate monitoring and management plan is in place.
Improvements at the landfill site have included creating new temporary leachate ponds and new bunding.
The site is checked daily for leachate compliance and when rain is forecast. Waste Management checks the ponds carefully to ensure they have sufficient capacity to divert stormwater away from the leachate ponds.
Council will continue to look for improvements wherever possible.
There has been no repeat of what occurred on 6 April 2017, including during the significant rainfall at the end of April 2018 - which resulted in widespread flooding in Rotorua and a state of emergency being declared in the Rotorua suburb of Ngongotaha.
Further work that will happen at the site includes planting of trees covering up to 3 hectares of land adjacent to the capped landfills and removal of vegetation from the old landfill cells.
Council commissioned a report on the landfill in 2015 which made a number of recommendations to address historic issues at the site. The work recommended would itself have posed a risk and would have seen the site still an open face tip. Council determined that the best way to protect the environment and public health and safety was to cap and seal the landfill and that decision was made in 2016.
The same year Council contracted Waste Management to take over the day-to-day management of the site and to progress work to cap and seal the landfill. Work to progress that started in 2016 and capping and sealing was completed in 2018.
The work to cap and seal the landfill was a significant investment, requiring extensive engineering and earthworks.
That work took some months to complete and the weather events of March and April 2017 occurred before the work had been completed.
When waste decomposes (especially organic waste) it produces gas and liquid. Leachate is the liquid produced in the landfill as a result of the breakdown of waste.
At the landfill site, the leachate is captured and directed into the wastewater system and fully treated at the Rotorua wastewater treatment plant.
Rainfall can enter into landfills naturally, which has the potential to flood and overwhelm leachate management systems. For that reason, it is important to manage stormwater so that where possible it is diverted away from leachate, and also to ensure that leachate management systems have enough capacity to not be overwhelmed.
In this case, stormwater entered the landfill. The mixed stormwater and leachate then overwhelmed and broke through the leachate system.