Flood Hazard and Flood Risk
We can’t control nature. But we can prepare ourselves for it. Berlin is ready should floods loom after extremely long or heavy rain.
On the one hand, flood hazard maps have been developed for this purpose. They predict the location, severity and potential water depth of floods. There are three scenarios: if peak water levels are likely to occur only every 200 years, there is a low probability. Areas affected by flooding every 100 years on average are assigned a medium probability. Areas affected more frequently than that, have a high probability. In Berlin, the shores of the Tegeler Fließ, Panke, Erpe, Untere Havel/Untere Spree and Müggelspree are in danger of flooding. They have been declared flood areas, which limits the options for development there, for example.
On the other hand, flood risk maps have been developed, listing the affected areas under each probability category. These maps indicate how many people live in those areas and whether, for example, a UNESCO World Heritage settlement or a water conservation district is at risk.
Relevant authorities and planners, but also the residents, can prepare themselves for the worst-case scenario using these maps. The maps focus only on flooding caused by high water levels of a river or a lake itself, however. They disregard the failure of dams or groundwater pushing up from the ground.