The installation of a new siren costs around 10,000 euros. Depending on the location, this can also be somewhat cheaper or more expensive, the spokesman for the Bonn professional fire department explains further. The costs for operation and maintenance amounted to about 400 euros per year per system. "The new sirens, unlike the old ones, are buffered with a rechargeable battery and can thus continue to operate for some time even in the event of a power failure." He also said their range is significantly greater than the old sirens.

In addition, the fire department has reportedly purchased 18 mobile warning systems. These emit a warning tone, and information can also be relayed via a loudspeaker system on the roof of the vehicles. Twice a year, there is a test alarm in Bonn. The systems are tested in March and September. Bonn was also involved in the first nationwide warning day last September. However, the day turned out to be a flop in large parts of Germany: At that time, it became clear that many municipalities no longer operated any sirens at all, and the messages from the warning apps Nina and Katwarn only arrived on smartphones half an hour late (the GA reported). For Frenser, however, the sirens are especially important, as they still have a "wake-up effect," he says.

According to Peter Esch, head of Bonn's civil engineering department, the measuring stations installed a few years ago at the particularly endangered creeks (Ippendorf, Lengsdorf and Endenich; the Hardtbach system along Duisdorf via Lessenich-Meßdorf, Dransdorf and Graurheindorf; in Bad Godesberg from the border of Wachtberg to the banks of the Rhine in Mehlem as well as the course of the Vilicher Bach on the other side of the Rhine) help to keep an eye on the water levels when storms with heavy rainfall threaten. In some cases, cameras are also installed at the culverts under the bridges, explains Esch. The costs vary for the different locations of the water level measuring stations and depend, among other things, on whether the location is equipped with a camera, whether there is already the possibility of a mounting for this, whether a mast must be set, whether a network connection is available or whether an energy supply must be provided via solar panels. Esch: "The range is from 7500 to 15,000 euros." Part of the maintenance is carried out by employees of the civil engineering department, for whom personnel costs are incurred. According to Esch, the commissioned maintenance of the measuring stations costs about 500 euros per site per year.

As soon as the measuring stations, which have three alarm levels, are on red, signals are received by the fire department, which then in turn sends so-called explorers to the affected stream courses, as Frenser explains. During the severe storm on Wednesday, July 14, alarm level 1 was triggered at the first three measuring stations along the Hardtbach system, followed by alarm level 2. Many cellars in Lessenich were flooded, the fire department had to evacuate some houses; in addition, debris and logs had accumulated on the banks of the creeks. In Mehlem, which had been hit hard by the last floods, the storm had a mild outcome thanks to the new spillway.

However, in the event of a disaster in Bonn due to a flood wave, the fire department can rely on many forces: The professional fire department has around 400 full-time employees, and the volunteer fire departments have up to 600 volunteer members. In addition, special vehicles could be used to rescue people from houses in flooded areas in an emergency. For example, the Bonn fire department currently has 13 vehicles that, unlike standard fire engines, can drive through deeper water - between 60 and 120 centimeters of water depth. These include fire trucks, as well as logistics vehicles and rescue vehicles. "The special vehicles have provided valuable services in the past in Bonn and most recently on the Ahr River," says Frenser.

In addition, there is close networking with the four aid organizations in Bonn - DRK, Malteser, Johanniter and ASB - and a concept for emergencies "that we can pull at any time." The fire department and aid organizations train for operations in the event of a disaster during regular large-scale exercises, such as in the Rheinaue. However, these exercises had to be suspended during the pandemic for reasons of infection control, says Frenser, who believes that the city of Bonn is well positioned overall for an emergency. However, even he could hardly have imagined a catastrophe like the one that occurred ten days ago on the Ahr, Swist and Erft rivers in these latitudes.

(Original text: Lisa Inhoffen, Translation: Mareike Graepel)