A map on the Internet shows where Frankfurt will be under water during the next heavy rain. Above all, your benefits point to the future.

The city of tomorrow must look different from the city of today. We know that – and the heavy rain hazard maps, which have been available to everyone since Wednesday at geoportal.frankfurt.de/starkregen, provide further evidence.

All areas are listed there that die in the event of a rare, exceptional or extreme rainfall under water; so crown the three categories. Those zones that would then be flooded more than a meter high are colored purple. This naturally includes the underpasses, such as the theater tunnel, but also the train stations, especially the Südbahnhof and Höchst. But many other places in the city are also at risk of flooding if the climate crisis gets serious and causes more and more heavy rain.

“In the future, due to climate change, we will have to adjust to the fact that such extreme rainfalls will become more frequent,” said climate and environment department head Rosemarie Heilig (Greens) at the presentation on Wednesday. The heavy rain hazard maps are not the solution to the problem, but the way to the solution. “We now have the first comprehensive overview of where heavy rain events occur,” says Environment Office Manager Peter Dommermuth. “The offices have been waiting desperately for this instrument.” In addition to the offices, the fire brigade and the city of Offenbach were also involved in its creation. The basis for the calculation is explained, among other things, by a digital terrain model, surface use plans, water courses and building contours – but not every curb was found, according to Alexander Kehl, Head of the Environmental Monitoring Department at the Environment Agency. It is always important to include the current situation on site.

Mobility department head Stefan Majer (Greens) reminds that at the Südbahnhof “real flash floods” rushed in the B-level and in the subway shaft until so-called hinged bulkheads at least helped. According to Majer, around 1800 so-called hazard areas in the city are identified by the heavy rain maps – 140 of these are access points to local public transport. “The fire brigade is ready if something happens,” he says, “but our goal must be that we intervene beforehand.” As far as the Nidda die and especially their tributaries are concerned, solutions are only possible together with the neighboring communities, especially in the Vordertaunus.

Speaking of solutions: What follows from the heavy rain hazard maps? What does the city do with the fact that the Frankfurter Berg is an endangered place, or the school on the slope in Bergen-Enkheim? What to do if the environmental agency has determined on the basis of the maps: Rüsterstrasse, east of Westendplatz, the area around Dominikanergasse and the intersection with Fahrgasse, Ostendstrasse – “these are areas that we hadn’t even focused on before”, such as Dommermuth says?

“We know the places where the heavy rain could hit mercilessly – we have to take precautions now,” says Rosemarie Heilig. In some places, authorities should also “urgently get their files out” before the water comes. Majer: “The card shows: Oh – a few people should soon take a look at what they keep in their cellars.” In other words: The cards help as a basis for the future. The development of building areas such as the luminaire in Bergen-Enkheim would “probably no longer be approached today”, says Majer.

Otherwise: self-protection is the magic word. The city will create retention areas where it can, says Rosemarie Heilig, and also direct areas where rainwater can collect without damage. This can be seen, for example, in the green areas on the Riedberg. But: Private property owners also have to prepare themselves and reserve areas for infiltration, for example.

More about heavy rain hazard maps and how citizens can protect themselves is explained in a leaflet that can also be found at www.frankfurt.de/starkregen. Help is available by phone, 069 / 212-71409, and by email: [email protected]