Status: 24.09.2023, 12:00 a.m.
By: Bernhard Jepsen
Fish died in the creek bed on September 17th. © Private
On Friday a week ago, the Wörthersbach was diverted to the new rainwater retention basin west of the former BHS steel construction hall. Unfortunately, the action caused collateral damage: the lower reaches of the stream ran dry, causing crabs and fish to die.
Peißenberg – Normally, the Wörthersbach, which is also popularly called "Stadelbach" in its course in the district of "Wörth", is a rather calmly flowing trickle. However, the fact that it does not carry any water at all has not happened so far, even during extensive dry periods in summer. But last weekend the time had come. The stream bed between the outlet at the new rainwater retention basin and the culvert at the Josef Lindauer House fell dry. On Monday, numerous calls were received at the town hall. Initially, neither the relevant authorities nor the municipal administration knew.
The cause of the drainage was then determined a day later. On Friday a week ago, the Stadelbach had been diverted into the new rainwater retention basin. Actually, the dam system is only supposed to retain water during heavy rainfall and the risk of flooding. But after the relocation, water flowed into the retention basin, but none out. Shortly before the throttle structure, the Wörthersbach seeped into the subsoil, which was not yet sufficiently compacted.
The new stream bed of the Wörthersbach meanders through the new rainwater retention basin. In order to prevent seepage in front of the outlet structure, improvements were made last Tuesday with heavy equipment and filling material. © Bernhard Jepsen
On Tuesday, therefore, the building yard and the construction company commissioned for the construction of the retention basin arrived. Gravel and clay were used to mechanically solidify the soil. But that wasn't the only immediate measure. Since then, water has been pumped into the lower reaches of the Stadelbach via a hydrant. In addition, Benedikt Beck – a freelance biologist hired by the municipality – has collected around 100 crayfish and stone crayfish as well as brown trout and eels remaining in pools. Reversing the rerouting of the stream was not an option for Mayor Frank Zellner: "We want to finish the rainwater retention basin," said the head of the town hall. The problems with the infiltration were "not to be expected".
There are calls on social media to "hold the culprits accountable"
Zellner is now hoping for rainy weather at the weekend. Then the artificial irrigation could be stopped at the beginning of the week. So far so good. Nevertheless, there was plenty of criticism on social media. In various forums there is talk of "environmental scandal", "mess" and "bottomless impudence". It also calls for "the guilty parties to be held accountable".
Also in the building committee on Monday evening, the dried up Wörthersbach was already an issue. Jürgen Forstner asked about the causes and criticized the Lower Nature Conservation Authority and the Water Management Authority. In the case of flood protection measures, according to the municipal council of the Free Voters, both authorities imposed massive environmental requirements and blocked procedures in some cases – "and then a stream dries up – and no one knows what". Otherwise, every single fly or mosquito would be taken into account: "And suddenly everything is fine," says Forstner.
The dry stream bed of the Wörthersbach in Peißenberg. © Ralf Ruder
The transfer of the Stadelbach to its new stream bed, which flows through the retention basin, had been approved by the authorities. According to Bernhard Müller, head of department at the water management office, the original and now abandoned section of the stream south of the basin was "properly fished out" – by Benedikt Beck. This, in turn, is perceived by the Weilheim Fishing Association as "very strange" in retrospect. In any case, they were not informed about the action, explains Managing Director Stefan Schröpfer when asked.
Water supply should be restored quickly
Background: The fishing association has held the fishing rights on the Wörthersbach for ages. From an ecological point of view, Schröpfer says, the drainage did not cause "the huge damage" - "even if every dead individual animal hurts". It is now important that the natural water supply is quickly restored. "Something else is certainly pleasing. But we don't want to nail anyone to the cross now," Schröpfer says conciliatory. The water management office has also given the all-clear. "It doesn't look like any major damage at the moment," Bernhard Müller confirms.
Benedikt Beck also speaks of a "manageable damage pattern". The large population of crabs can be found above the rainwater retention basin anyway. In addition, the company had "reacted relatively quickly with emergency measures" to the dehydration. What's more, with projects such as a stream relocation, adverse effects on flora and fauna could never be completely avoided. Residents, on the other hand, report to the local newspaper that numerous fish and crabs had already died in agony at the end of May during a "test closure" of the now completely abandoned section of the stream next to the retention basin.