Personal precautions against flooding and heavy rainfall

In some parts of the city, there are areas that are at risk from flooding or heavy rainfall. These can be taken from the  flood hazard map (HWGK) of the state of Baden-Württemberg (opens in a new tab) and the  heavy rain hazard map (SRGK) of the city of Stuttgart.

The flood hazard (HQ) is given in annual values and quantifies how often flood events can statistically occur. The abbreviation HQ stands for the discharge volume during flooding. For example, with HQ10, HQ50 or HQ100, a flood can be statistically expected every 10, 50 or 100 years. In reality, however, such an event can occur more frequently and climate change is also increasing the probability of heavy rainfall events.

 Heavy rainfall events (opens in a new tab) can also lead to flooding far away from bodies of water. Properties on a slope, in a hollow or in a valley are particularly at risk. The sewer system cannot be designed for heavy rainfall, as this would be neither economically nor technically feasible. Such events can also lead to backwater on roads and surfaces.

In the  flood hazard map view (opens in a new tab), you can display the desired inundation areas and flood depths in the city area. To do this, click on the "Specialist data" area in the top left-hand corner of the map via the "Topics" menu.

Active warnings of heavy rainfall events and the associated increased probability of flooding are provided by the  Federal Office of Civil Protection and Disaster Assistance with the NINA warning app (opens in a new tab) and the  German Weather Service with the WarnWetter app (opens in a new tab).

The warnings are also broadcast in the public radio media and usually cover larger areas, as it is not possible to predict exactly where heavy rain will occur, especially during summer thunderstorms.

According to the Federal  Water Resources Act (opens in a new tab), anyone who may be affected by flooding is obliged to take precautions against flooding as far as possible. The construction and extension of buildings is generally prohibited in designated flood zones. Exceptions are only possible through flood-adapted construction methods in consultation with the lower water authority.

There are three strategies for flood-adapted construction projects. Some of these measures are also possible for existing buildings:

• Evasion: Building outside the danger zones, such as using elevations or elevating buildings.
• Resist: Preventing water from entering, for example by using (mobile) protective equipment, sealing house walls, windows and other openings or installing shut-off valves, such as the non-return valve in the connecting sewer.
• Giving way: Preparation for (partial) flooding by selecting suitable building materials and appropriately planned room use with possible floating protection for furniture.

The civil engineering department of the state capital Stuttgart monitors, maintains and cares for the streams and rivers in Stuttgart and thus ensures good water drainage in the watercourses in the city area.

In addition, the Civil Engineering Office operates 55 flood retention basins to protect citizens from accumulating water. On the Neckar and Feuerbach rivers, for example, there are dams and walls that protect the surrounding area from flooding. The protective measures will be further expanded.

Other bodies of water will be successively examined for their flood risk. The flood hazard map is being updated and recommendations for flood protection are being drawn up.