Werner schaup sits in front of a revolving shelf and takes out a folder on the subject of flood protection. Since the catastrophic rain in the summer of 2007, nearly 20 folders have accumulated. Schaup, head of the civil engineering office in forchheim, pays for: design plans, further plans, plans for "preventive flood protection in kersbach, ground surveys…
Everything is ready to start with the construction of protective measures. But the crucial question has not been answered: will the municipalities of forchheim, baiersdorf, langensendelbach, effeltrich and poxdorf succeed in joining forces to form an association?? In other words, if the five potential partners in a special-purpose association can agree on who will pay what share of the 30-million-euro flood protection project, it will be up to them to decide?
Flood protection is difficult to communicate to the public, says werner schaup: "you can’t make people understand that we’re working on it because they can’t see anything."
Mayor franz stumpf understands the impatience of the population. It "worries" him, he recently told the city council that no "solution for flood disposal" had yet been found for kersbach and burk found.
From a purely planning point of view, the solutions are in the drawer. The "negative messages, of which stumpf speaks, refer to the zweckverband baiersdorfer raum. There is a dispute about the funding distribution key. In december, the mayor of oberburg added another percentage point: forchheim was prepared to pay 15 percent. This was stumpf’s final offer. "Should be completed by 31. If no solution is found, forchheim will withdraw from the special-purpose association."
As complex as the subject may seem, the core of the matter is very simple, outlines schaup: the water from langensendelbach, poxdorf, effeltrich and kersbach ultimately arrives in baiersdorf. Four large ditches dominate the landscape: the schaeihergraben, the kreuzbach, the regnitzgraben and the schwolgraben. These four inlets produce a peak flow of 40 cubic meters per second in the event of a flood wave such as the one in july 2007.
If the water masses are to reach the main-danube canal without first flooding baiersdorf, the so-called kreuzbach culvert must be suitably coarse. To be precise: it must be twice as large as it currently is. In addition, a retention basin had to be built to the east of the railroad line to allow the water to flow away at a reduced rate.
The communities above baiersdorf have their own flood problems, but they can’t solve them without baiersdorf. Because, says werner schaup, the "treatment of water" that stumpf talks about a law applies: "it is forbidden to simply pass on the water to the underlying municipalities." For the flood wave that arrives in baiersdorf, the others are also partly responsible – and they have to pay to contain the wave.
That’s why the water management office put the brakes on the forchheimers when they started planning an islandization. Werner schaup understands the strategy of the kronach authorities: "a joint solution makes more sense, and there are no technical differences of opinion between the municipalities." But, at the same time, the civil engineer emphasizes: "the alliance must function in such a way that the kersbach problem is solved right from the start." This means: the water of the schwolgraben has to be diverted past kersbach.
If the five potential partners do not come to an agreement, the forchheim island development could be realized. Legally, this is possible, says werner schaup: because the construction of a 55,000-square-meter retention basin in kersbach made it possible to pass on only 500 liters per second "and that’s legally okay".
This island solution would look like this: the water coming from the schwolweihergraben is led into a retention basin. The basin is a roughly 55,000-square-meter flat area bordered by a wall and designed as a recreational area. Around 64,000 cubic meters of water could be collected in this basin before it continues to flow towards the danube canal. Consequence of the throttling: the water masses, which previously flowed uncontrollably towards the pfarrgartenstrabe (the lowest point of kersbach), could be bundled and forwarded in small quantities.
Functional protection from 2014
64,000 cubic meters, about the same amount as the rain that hit kersbach in 2007. In 2012 and 2013, the people of kersbach were also exposed to such a "heavy rain" unprotected. But if the city council gives the go-ahead for the islandization at the end of march, the flood protection system in forchheim would be "operational by the end of 2013", estimates werner schaup.