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An Aargau floodplain forest is cut down. Because underneath there is an old waste dump that needs to be rehabilitated.
Waste handling in Switzerland was relatively careless up until the 1960s. The waste was dumped somewhere on the outskirts of the village or town, and that was it. Years later, this takes revenge, many communities have to clean up their former landfills. A special case is the remediation of such a landfill in Windisch, at the so-called “water castle” in the canton of Aargau.
The “Fröschegräbe” area is somewhat hidden in the forest, near the confluence of the Aare and Reuss. On a walk, pensioner Ernst Rauber remembers how the “Ochsner buckets” with municipal waste were emptied here. “People also came from neighboring communities and dumped everything, even leftover paint. That was just the way it was, »says the Windisch eyewitness.
The landfill was later closed and developed into a nature reserve over the decades. Today the area is considered an amphibian spawning area of national importance. The problem: The floodplain protection forest looks natural from the outside, but the subsoil is heavily polluted, as cantonal studies have shown.
There is poison in the nature reserve
Zinc, lead, PCBs (poisonous chlorine compounds, formerly used as hydraulic fluids and plasticizers) and other substances are stored in the ground. “We know from the soundings that there is construction waste here in addition to household rubbish,” explains Mayor Heidi Ammon (SVP).
The floodplain forest «Fröschegräbe»
The canton therefore ordered a complex clean-up: several hundred trees had to be felled on an area the size of around three football pitches, then the contaminated sites were dug up and the landfill was refilled with new, clean soil from the area.
The costs, which are mainly borne by the federal government and the canton, are around CHF 2.5 million. However, such a complex clean-up does not always make sense, explains Michael Madliger from the Contaminated Sites section of the Aargau Department of the Environment. The encroachment on nature is major, and it will take years for the protected floodplain forest to recover from this encroachment.
Nevertheless, in this case it is worth cleaning up the landfill, the mayor and the cantonal expert are convinced. Because it’s about groundwater. “One of the most important groundwater intakes in the canton is in this area,” explains Michael Madliger.
In Aargau alone there are 600 former waste pits. Many of them stay where they are. However, there is a need for action at 58 landfills: They are permanently monitored or even completely rehabilitated, as in Windisch.
A little history of waste disposal
It was not until the 1970s and 1980s that politicians in Switzerland introduced more strictly regulated waste management. The first waste incineration plant was opened in Zurich in 1904, but Basel and Bern only followed suit in the 1950s. “And it took a little longer for these communities to realize that the supposedly harmless waste was actually a problem,” says Madliger.
Now, some of these traces of the past are being removed at great expense. However, the “waste problem” is far from being solved: other countries still have no waste incineration plants. And construction waste, for example, still has to be landfilled in Switzerland, as there are still no sensible recycling options.