What is a flash flood alarm

By Regina Bluhme, St. Wolfgang

The fear of a flash flood like in Simbach in Lower Bavaria last year does not leave the mayors in the district in peace. St. Wolfgang is currently having floodplains determined in the area of ​​the municipality. For the first time, this also includes calculations for heavy rain. Among other things, the report is intended to serve as a basis for future flood protection measures. In the district as a whole, the issue of funding for protective structures is under discussion in the district, which not all municipalities receive. The Munich Water Management Authority sees the funding guidelines as "new challenges" due to the new weather phenomena.

"The municipality of St. Wolfgang is currently having floodplains identified in order to gain in-depth knowledge of the dangers of flooding in its municipality", is how Gabriele Merz, deputy head of the Munich Water Management Office, sums up the project. In these planning documents, among other things, it is simulated how the runoffs of the waters react to certain amounts of precipitation. The branch manager of St. Wolfgang, Christian Miksch, speaks of a "heavy rain hazard map" when it comes to the planned report. Not only would the bodies of water be examined, but this time also the runoff from streets and canals. At the same time, the topography and development on site are also taken into account.

As Christian Miksch reports, the community is currently waiting for corresponding offers from three engineering offices. After the decision on an offer, the funding application will be submitted to the Munich Water Management Office. According to Gabriele Merz, the costs for this planning can be funded up to 75 percent.

From the future documents on the floodplains, St. Wolfgang hopes to be able to sound the alarm before a flash flood occurs, says Christian Miksch. In addition, the documents are also intended to help "look very closely and, if necessary, check the location" when designating building land. And of course the project is also the basis for further considerations "which flood protection measures are necessary on site", says Miksch.

Such a basic determination is "a very good measure for services of general interest" and in principle eligible for funding for every municipality, adds Merz. What the municipality decides on the basis of this flood report for protective measures, for example the construction of retention basins or polders, is a matter for the municipality. "Measures to protect those affected in areas that are considered to be at risk in the event of a 100-year flood event are, however, eligible," said Merz. In St. Wolfgang, for example, there are several third-order bodies of water and thus funding could flow here for protective measures.

But how does it look in areas that have no third-order bodies of water, "without a specific waterway connection", as it is called in official German? There currently no protective measures could be funded by the water management, so Merz. Nevertheless, there are funding programs from the agricultural administration, she adds. But the deputy head of the water management office also says: weather phenomena such as the "undoubtedly increasing heavy rain represent a new challenge" and it could well be that "the funding guidelines will be adapted to the new challenges". However, nothing is ripe for a decision.

Perhaps this statement gives Hans Wiesmaier hope again: The mayor of Fraunberg and district chairman of the Erdinger Municipal Association urges that all municipalities in the district should receive funding for their protective measures against flooding. "Simbach has shown that it can actually affect any community, even one where a flood has never occurred," emphasizes Wiesmaier. Some communities feel that they have been left alone in the expansion of flood protection. "Often there are many smaller measures that are not funded - it cannot be that only large projects receive funding," complains the district chairman of the Erdinger Municipal Association. The guidelines should be changed due to the new weather phenomena. "There should be support for all communities that set out to protect against floods."