Going to Waste: A Look at Christchurch’s Landfill by the Lake

An #iSeeChange story

Image: Burwood Landfill in Christchurch, New Zealand (Lily Bui)

CHRISTCHURCH, NEW ZEALAND — Imagine you are hiking through a serene temperate forest surrounded by pine trees and crisp morning air. Suddenly, you come across a sign that points you toward, of all things, a landfill.

Two weeks ago, this happened when I went mountain biking at Bottle Lake Forest Park, a recreational park northeast of Christchurch’s city center. I noticed some dusty trees near where the park meets the landfill, so I made this post on iSeeChange, a citizen science and public media project about climate change. A question had begun to nag at me. What are the environmental impacts that come with juxtaposing woods and waste?

But first, some context. The placement of this particular landfill was a direct result of a recent brush with catastrophe. In 2010–11, aseries of earthquakes shook the city and claimed 185 lives, destroying a significant amount of infrastructure. After the quakes, an area of Bottle Lake Forest Park was designated as a repository for demolition waste while the city rebuilt. It is still being used.

In essence, my question was really about how catastrophes can prompt, even accelerate, environmental change.
Image: Dusty trees near the landfill (Lily Bui)

According to the Christchurch City Council website, rubble and silt from the earthquake is being recycled at the park, and the area is slated for rehabilitation around 2020. “Exclusion zones” on the official park map delineate areas reserved for landfill-related activity. If you look up a recreational map of the forest, you might come across something like this:

Image: Exclusion zones delineate where the landfill areas are. (Christchurch City Council)

Increasingly curious, I decide to pose my iSeeChange question to a park ranger. Warren Hunt, the Bottle Lake Forest park ranger who is kind enough to answer my e-mail, invites me back to the park so he can give me a closer look at the landfill. When I arrive by bicycle, we hop into his four-wheel drive (‘4WD’ in Kiwi shorthand) and drive past the landfill gates.

Image: View from the 4WD, passenger side (Lily Bui)

On the way over, he tells me that the area has actually been an official city landfill since the 1980s but was closed when the nearby Kate Valley Landfill replaced it in the early 2000s. Burwood only recently opened up its gates again to accept rubble (i.e. concrete, wood, metals, and other structural materials) after the earthquakes and is managed by Burwood Resource Recovery Park (BRRP).

“While it’s a major disruption to the forest, I believe it’s for the greater good of Christchurch,” Warren says, reassuringly.

At one point, we end up at the base of a tower of rubble, at least two stories high. I am taken aback by the fact that I’m looking at what used to be a building, or several buildings. Up close, I’m able to catch fragments of the anthropocene: a window frame, a room partition, broken benches, door knobs, table legs, car bumpers. This visual archaeology is stunning and simultaneously eerie.

Out loud, Warren recalls taking another visitor to the same site who became emotional at the sight of a New Zealand flag stuck in the debris. Warren had let him keep it.

Images: Up close to the rubble at Burwood Landfill. (Lily Bui)

An initial report drafted by Environment Canterbury Regional Council (ECAN) in July 2012 outlined some anticipated environmental effects of storing demolition waste at Bottle Lake.

For instance, storm water runoff poses a risk to the adjacent ocean and forest as well as the soil beneath the landfill. Increased levels of chloride, iron, and leachate in groundwater have been reported in ECAN’s initial findings after demolition rubble began to make its way into the site. As yet, after thirty years of operation, regular tests have not found evidence of leakage into the sea.

Waste that gets buried underneath the ground in the landfill produces carbon dioxide and methane gas, which does not occur in large volumes when the weather is not too rainy or not too humid. However, according to research in the Bottle Lake Management Plan, “each tonne [sic]of refuse produces 200 cubic meters/tonne of landfill gas.” That means even if the rate of gas production is low, the process of gas production is merely slowed down, not halted completely.

In due course, the city has come up with a clever solution for this problem: converting gas byproducts into energy for reuse. Warren tells me that the methane gas produced from the landfill was previously used to heat QE2 Park, a large community pool nearby: “The methane from the landfill powered the whole complex.”

Image: How methane gas from the landfill is collected and used to generate electricity. (CCC.govt.nz)
Image: The “Recovernator” processes the earthquake waste to sort through metals, timber, rubble, and soils. (TransWasteCanterbury.co.nz)

“The use of landfill gas as a fuel for generating electricity is well proven in New Zealand and overseas,” says a source from BRRP, Ltd. “The new Kate Valley landfill in Canterbury should generate enough electricity at its peak to power all of north Canterbury.”

Waste, an inevitable byproduct of human presence, is an essential aspect of city management — and sometimes a markedly un-lovely topic. However, the way in which cities address waste’s removal and return to the environment can speak volumes about its values.

(In some instances, some smart city projects have experimented with ways to track the location and to more efficiently monitor levels of waste.)

Storing demolition waste at Burwood Landfill is certainly a temporary solution — the result of a challenging decision made to mitigate post-disaster circumstances. The original plan for reopening Burwood bears the recovery process in mind not only as something possible but something that is necessary.

While the long-term environmental impacts of using Burwood Landfill as a demolition repository remain to be seen, as Warren says, in the meantime, “We’re managing it.”

Do you have a question about changes you’re seeing in the environment? Join the climate change conversation and post it on #iSeeChange.

Lily Bui researches sensor technology for #iSeeChange and is also a M.S. candidate for MIT’s Comparative Media Studies program. She is working on some urban sensing projects while cycling around Christchurch, New Zealand.