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On the night of July 14th 2021, endless rain turned this stream into a massive flood. It was a once-in-a-century flood, and it turned the Ahr valley into a huge experiment in how to prepare for the next big one. Because while building back, people here have been working out many small and big fixes, so that this can never happen again. "There's a lot of construction work going on here." This is where the flood came through five years ago. The total rainfall for an entire month in two days.
It washed away cars, houses, trees, piled them up against bridges, and - once they broke, the wave rode on with even greater force. The Ahr river runs over 85 kilometers from a mountainous region into the Rhine River in Western Germany. On its way down, the water killed 135 people and razed many parts of the valley to the ground. Especially here, in the town of Bad Neuenahr-Ahrweiler. "This all looks very makeshift." I'm here to meet the people who are building back better.
"Hello." Some of whom barely survived the flood five years ago. "Since we lived near the Ahr River, my neighbors and I kept going down to the river to watch it. At 10:30 p.m., I noticed that the water was rising rapidly. You could hear something coming toward you. At that moment - practically in that very second - I turned toward the street where we live, and the water was already rushing in. It was practically coming from every direction." She lived just 50 meters from the river back then, in a neighborhood like this one.
She didn't want to show us the place - that's still too painful - but she did send these videos of how it started. "I went back into our house where my son was still asleep. I pulled him out of bed, and we fought our way through the water. We encountered all sorts of things along the way - garbage cans, branches, and who knows what else. At one point, I lost my strength and told my son that we won't make it." That was before the local government asked her and everyone else to evacuate. Around the same time, a police helicopter was filming the scenes in the valley from above.
People are sitting on rooftops, using their flashlights to signal for help. For most of them, it didn't come that night. Alexandra Wiemer made it to her mom's house, a little up the hill. And even here, the flood was still passing by the next morning. When she got back to her own home, nothing was the way it used to be. That's also why in her new home, a couple of things are different. "Here, the wall was built and raised quite high. The basement windows are down there. The flood barriers were added later. And if all else fails, we still have sandbags that we can place in front of the windows."
"Wow, that's very sandy and heavy." "And why are they already lined up out here?" "These are precautions so that if anything happens, we can act quickly." But this new home is just as close to the river as her old one. "Why did you decide to keep living near the Ahr after all?" "Because it's nice to live by the water, and because I'm not afraid to keep living here by the Ahr. Period." She says that all the flood survivors she knows have stayed in town. Then, if people don't move away from the river, and the risk of another flood, they have to adapt to it.
Judging from all the construction work going on in this town, they are. Five years ago, 80% of the town was flooded. Like here, where the water breached the medieval wall and submerged the historic old town. Hermann-Josef Pelgrim is one of the organizers of this new extra wall. "The idea here is to use an engineered rock structure - a retaining wall - to prevent the river from breaking into the historic old town. It's a very solidly anchored wall, built with bored poles 1.20 meters in diameter and driven 15 meters deep." This way the water can't get under the wall either and make it collapse from below.
"So, it hits the wall, flows on, but doesn't it run in there? Isn't that the weak spot?" "Yes, you're absolutely right." This is the same weak spot five years ago. The water crashed right into the fire station. You can still see the tiles from where the truck washroom used to be. "Was the fire department able to help, or were they unable to help?" "No, they couldn't help here - the water was meters high.
The fire department was unable to function at this location." To avoid this, the new fire station is being built on the other side of the river, where the force of the water is less intense during a flood. And its being built on underground stilts so that the station will not collapse. The town is also setting up green spaces with underground trenches. They help to catch and carry away water during heavy rain. And the 16 bridges that have been destroyed get upgraded. This medieval one was torn down by all the debris and cars that crashed into it. These bricks are all that's left of it. And this is the new one.
"This bridge will not collapse, even in the event of extreme flooding." "Under no circumstances?" "Under no circumstances." Because everything should fit underneath, water and debris. Other locations will soon get another kind of bridge that can be lifted up. The town is spending more than €1 billion on reconstruction. The money mostly comes from a fund set up by the German federal and state governments. But despite the huge effort here, there's a catch.
"Anything that isn't caught upstream ends up in the river downstream. In other words, it's a shared responsibility." So, let's go upstream. Driving up the river, I get the feeling it's not just how much came down here during the flood. But also, that there's so little space everywhere. On this map from about 220 years ago, you can see that in many places we just saw, there was hardly anything back then. The Ahr meandered freely, sometimes with several arms at the same time. But then, as people moved into the valley, they channeled the river and built on its banks.
This makes flooding more likely - which is exactly what happened in the place we are headed now. This used to be a camping ground and now it's just completely empty. The water level here was among the highest during the flood five years ago. It rose to the same level as this church. "The water here was several meters above our heads. You can still tell by the dirt on the building across the street, for example, which hasn't been cleaned up yet." More than seven meters above ground.
The town was submerged in water. Most of it was rebuilt, but not this piece of land. This man, Bruno Büchele, has got totally different plans for it. "You can tell how the slope drops off here and the entire riverbank has become flatter. The area that has been lowered here used to be part of the river's old course." The area gives the river space to flatten out and is an experiment to let nature take over again. The same thing is being done all along the river, including in the town we went to earlier.
Büchele says that locals along the river sold parts of their land to make space for these plains, with grasses, shrubs and trees. Others were skeptical, because uprooted trees blocked and damaged bridges during the flood. The plan for the river course now is a mix of narrow spaces, where flood can pass through without water and debris pooling up, and then those wide and wild areas where the water can spread and slow down. Makes sense to me. But that's still not all. "Right here along the waterway, we can take many preventive measures by creating more space, but of course these efforts will only be fully effective
once retention measures are in place to technically reduce the volume of runoff arriving here." Isn't German such a beautiful language? It literally means holding back measures. And to see what that means, we need to drive up the river a little further and into a side valley. Okay, looks a little boring, to be honest, but apparently that's a really big deal. We've got a stream down here, we've got a little dam with a gate. And then all of this is a big low-lying plain. So when it rains really heavily, and that stream grows bigger,
the water will fill that plain and not hit the village. Simple as that. This is the basin during the flood five years ago, 40 million liters of water. It did leak a little, but didn't break. Just like a second basin outside this town. And that's what "saved their asses", a local official told me. And because they worked so well, 17 such retention basins are now planned along the Ahr and its tributaries. Just way, way bigger. Like, a hundred times bigger. This example from another place in Germany shows what they could look and work like.
It's a 28m high dam that includes tunnels for road traffic and wildlife. In normal times they are open. But when a flood is brewing, they are closed, and the water is retained. If it all goes to plan, construction of such dams in the Ahr Valley will cost more than €1.5 billion and take decades to build. Provided nobody forgets about the flood. Plans for such basins were already made after another devastating flood in 1910, so more than a century ago. But those old plans were never put into practice. The money was used on a nearby racing course. the Nürburgring, instead - as if the flood hadn't happened. "Risk seems quite abstract and distant.
We hear about it, we read about it, but we never think we are going to experience that." But according to climate vulnerabilities expert Indu Murthy, major floods happen all the time, and in many parts of the world. In the past months alone, in China, southern Africa, Indonesia and Afghanistan. Floods killed at least 3000 people and destroyed billions of dollars in infrastructure every year. "When we say 'one-in-a-hundred-years-flood', it does not mean it will not happen for 100 years. What we are meaning is that there's a 1% chance in any given year for that magnitude of flood to happen."
The science is clear that the risk is increasing as cities grow bigger and global warming accelerates. Warm air holds more moisture, which makes rain more heavy. But just as the risk is known, so are the defenses. "Many effective measures are also low cost, whether we are talking early warning systems, community preparedness or land-use, zoning and nature based solutions, they are dramatically cheaper per life saved." There are countries and cities from Bangladesh to Singapore and the Netherlands, that use all these measures to protect themselves. And it's very much what we see happening in the Ahr valley too. So what happens when the next flood is brewing here?
If it all goes to plan, the retention basins along the Ahr and its tributaries are the first line of defense. This chart shows how much the water levels would drop if the basins were closed and filled, compared to the flood five years ago. In short: quite a lot. Further down the river, like in Altenburg, it could safely spill over into those new floodplains. And with new walls and bridges in Bad Neuenahr-Ahrweiler, the water would largely just run off - while the firefighters head out safely from their station on stilts. And Alexandra Wiemer, what would she do? "Then I would run straight into the vineyards - out of experience - to save us, to save our lives."
"How far away is that from here, roughly?" "It's not that far away. If we hurry, we're there in four minutes." that can make all the difference. I'm honestly impressed by how much is happening here along this river. Certainly a lot to learn from. Big, expensive efforts - too expensive for many countries - but also small, low-tech fixes. When the next flood comes, we will know whether it has paid off. Is flooding a risk where you live? And if so, how do you prepare? Let us know in the comments below! Subscribe for more videos like this and check out dw.com for more stories.
