I grew up one kilometre from the edge of a brown coal mine and surrounded by many others. I remember staring in awe and fear at this massive hole, scared of getting too close after hearing stories of people buried alive because they walked along the unstable mine walls.

My family lives in the Lausitz region of Germany once home to 30 brown coal mines. Situated between Berlin and Dresden, the region has been shaped by this industry for over 100 years. It was the German Democratic Republic’s energy powerhouse – its Latrobe Valley – with coal mining the largest source of jobs.

That changed with Germany’s reunification, when the economy restructured to a market approach and most of the mines were closed. The only major industry was gone, leaving the countryside punctured with massive holes, and the community with big questions about how to make the region viable again.

The Latrobe Valley in Victoria, Australia, is starting to face similar changes. Hazelwood power station and mine shut down a few months ago and the world is moving away from fossil fuels. People are asking the same questions we did in Germany 15 years ago: how do we transition to a more diverse and sustainable economy, while continuing to provide jobs for local workers? What do we do with the dangerous pits left behind?

The same solutions are put forward too. Engie, the owner of Hazelwood, is proposing to fill all or part of the mine pit to become a lake and recreation area. The inspiration comes from the Lausitz, but some of the key challenges of this solution seem not to be given enough attention.

In my early teens, as I watched these massive mines around our house fill with water, I got excited about the prospect of living in an area renamed ‘Neuseenland’, meaning the land of new lakes. But while I was able to enjoy summer days swimming in some of these flooded mines, the process of filling them with water has been very slow. Many have already been filling up for 10 or 20 years, and are still a long way from being safe.

This is in a region of Germany with plenty of water. The huge pits could be filled with combinations of diverted waterways, groundwater access, rainfall and large amounts of reprocessed mining water, transferred from other nearby operating mines.

These water sources are not available to the same extent in the Latrobe Valley. To give a sense of scale, it would take more water than is in all of Sydney Harbour just to fill one of the brown coal mines. Where will all this come from? What are the downstream impacts of taking this much water? Would a lake be safe for the public to use? The Hazelwood inquiry into mine rehabilitation identified these looming challenges, and the Victorian government has created a rehabilitation commissioner and an advisory committee to start finding answers, but right now we just don’t know.

Then there’s the environmental contamination. In the Lausitz, mining had already polluted the waterways with high amounts of iron hydroxides, calcium and sulphates. Flooding the mine pits spread this pollution even further, degrading local ecosystems. Increasingly salty waterways now threaten drinking water supplies to Berlin and surrounds and make water management more expensive. Mining companies are the biggest users of water but don’t even have to pay for it.

For local communities, other major consequences include rising groundwater flooding basements, cracking building structures and shifting the ground.

Landslides are a real worry. In the Lausitz in 2009, a 350-metre wide strip of land – including buildings, a road and a viewing platform – slid into the adjacent pit lake, burying three people. In 2010, in an area where the former mine surrounding was regarded as very stable and settled, 27 hectares of forests sank into the earth. This will come as no surprise to people of the Latrobe Valley, where the Princes Highway was closed for eight months in 2011 due to landslides related to the adjacent Hazelwood mine.

There have been many more such incidents in the Lausitz, and the risk prevents whole areas from being accessed, which were used for farmland, wind farms, industry or forests. Yet when the Lausitz is promoted as the poster child of mine rehabilitation through flooding, many of these challenges aren’t mentioned.

Community consultations on the future of the Hazelwood mine will begin in September. So far, the community has expressed many ideas other than filling the mine pit with water but these remain ignored. Engie is unwilling to release the full list of rehabilitation concepts they considered before settling on the pit lake solution. This makes it difficult for the community to understand the recommendation and weigh it up against alternatives.

Before more planning proceeds on the assumption that a pit lake is the only option, the lessons learned from the experience in the Lausitz should be aired and discussed in the Latrobe Valley. It’s important to avoid the potential negative consequences of flooding mine pits as best as possible from the beginning, and to make sure the mine owners pay for the precious water they are taking, like everybody else does.

Most of all, the community needs to have a bigger say in what happens to retired mine pits. Like me, the children of Morwell, Moe and Traralgon in Victoria will grow up surrounded by massive, dangerous holes in the ground. Their families have the most at stake in what happens, so they should have the loudest voice in shaping the region’s future, not the corporate mine owners who shaped its past.