Solutions to solve the Intergenerational Inequity of our Legacy Landfills

Climate change will continue to reveal the disconcerting legacy of waste management in Aotearoa New Zealand. This was highlighted following the flooding of the Fox River township on the South Island’s West Coast in March 2019, where a legacy landfill eroded and distributed over 15 tonnes of municipal waste along 50km of pristine coast.

The cost of the clean-up was over $2.8m, which the Government paid for as it was unaffordable for the local authority. While there was significant media attention over this incident at the time, sadly, it is not unique.

Following the flood, the Ministry for the Environment (MfE) produced a climate change inundation/flood risk assessment tool to quantify the landfill sites at risk. Current reports suggest there are somewhere between 300-400 across Aotearoa.

How did we get to this point?

A combination of informal dumping and poorly sited local landfills - typically in obscure, convenient, ‘low-value’ locations such as gullies, gravel pits, mangrove swamps and low-lying areas - has resulted in many of the problems we face today.

Up until the 1970s, there was a lack of awareness of the environmental impacts of waste disposal, or a true understanding of the future impacts of climate change on landfills. There were limited controls of municipal and industrial waste, and it wasn’t until the 1980s that more active landfill engineering through things like landfill lining and guidelines were introduced.

While waste content has changed over time, waste management has improved with knowledge and awareness. With these advances we must now solve the issues associated with legacy sites.

Are we properly set up to solve this problem?

The Full Cost Accounting Model developed by MfE encourages planning for all phases of a landfill lifecycle, including a provision for 35 years of aftercare.

A national review of Long Term Plans (LTPs) by Audit NZ highlighted a gap in financial planning. The expectation for the current round of LTPs (2021-31) is that “councils should actively seek to identify the potential effects of climate change on their assets and activities. Assumptions about climate change and its effects should be based on sound supporting information and should be key building blocks for the LTPs.”

Who will fund this massive undertaking?

The cost of remediating 300-400 at-risk landfill sites is enormous (hundreds of thousands of dollars per site) and in most cases, it’s a challenging undertaking.

Some argue that those who generated and dumped the waste are responsible. A different perspective is that the environmental impact of waste and risks associated with climate change were not anticipated when these sites were developed, resulting in an unfair burden to those in charge of dealing with the effects today.

Are there solutions to the funding conundrum?

Identifying funding streams for the remediation and protection of these sites now is paramount. For a long period of time, New Zealanders have benefited indirectly from low-cost waste disposal strategies that resulted in these sites.

A remediation fund set up as a further extension of the linked waste minimisation levy makes sense. Managing such a fund centrally in a similar way to the Earthquake Commission (EQC) may have some merit. Contributions from landfill owners could be based on risk levels, which could arguably be more effective than each landfill owner setting aside their own contingency fund.

MfE are currently seeking proposals for a new waste strategy, so now is the perfect time to be looking at potential solutions for this legacy issue.

We must do a better job of turning risks into opportunities

With an increasing population, rising land costs, greater demand for development and open space, income-enhancing site remediation may be financially viable. By using landfill mining techniques, we have improved the performance and resilience of landfill sites (e.g. Barrie’s Landfill, Ontario).

Advancements in geotextile capping products facilitate broader use of closed landfill sites. They appear more resilient to storm bursts than traditional clay caps, and can reduce long term care by up to 90% by minimising infiltration and leachate production.

Lightweight concrete has been successfully used to address weight/stress distribution challenges (e.g. building developments and shipping container storage yards) allowing broader land use opportunities for some sites.

The impact of landfill improvements that uplift the land value around a site should also be considered. Pohe Island in Whangārei is a great example of a landfill site redevelopment that benefits the community. This site now provides both passive and active recreational opportunities with walking and cycling paths, a skatepark, sports fields, BMX tracks and further plans for a destination playground. These are important opportunities for inclusive, culturally responsive projects that meet community aspirations and may attract commercial activity around them.

Development with a future-focused mindset

The race to achieve carbon neutrality around the world is on. Te Mana o te Taiao, the New Zealand Biodiversity Strategy, calls for the potential for carbon storage from the restoration of indigenous ecosystems to contribute to our net emissions targets.

WSP Sweden’s Scott Cole, argues that the value of nature has rarely been factored into the price of land in his article ‘Biodiversity Offsets: The Price of Survival’. This is true for New Zealand’s closed landfill sites, as in most cases operators didn’t have to pay for the destruction of nature. Imagine if we could flip this by establishing an opportunity to increase carbon credits and turn sites from financial liabilities to income producing havens of biodiversity?

Conclusion

Closed landfills - particularly the 300+ sites that have been identified as being at risk from the impacts of climate change - represent a huge financial burden for Aotearoa as well as a significant reputational risk for our image as an ecological haven.

If we don’t act now, it is clear that more landfills will succumb to climate change, risking environmental and human health and the cost of remediation will increase.

No one of the ideas and innovations identified above will be a magic bullet for all these sites but the important thing is that we must broaden our thinking beyond traditional approaches, and we must act now, to prevent exacerbating the financial burden for future generations.