Aare river power plant Rupperswil Numerous fish die in the Aare because of a disturbance in the power plant

Aare-Flusskraftwerk Rupperswil, Hundreds of fish died in the river due to a technical failure at the power plant From July 30th to July 31st, hundreds, possibly thousands of fish in the Aare River near Rupperswil died as a result of a disruption at the hydroelectric power plant, according to the national fishing association. The water level at the SBB power station dropped by 2.5 meters overnight, effectively drying up the fish migration path. According to the SBB, the incident was caused by a technical malfunction. The local fishing association has filed a complaint. The Rupperswil-Auenstein run-of-river hydropower plant produces approximately ten percent of Switzerland’s railway electricity. At the end of July, a technical issue led to severe consequences. “On the night of July 31st, the water level at the Rupperswil-Auenstein power plant drastically dropped by 2.5 meters due to a technical problem,” explains Alexander Roschi, spokesperson for the Swiss Fishing Association (SFV). The power plant, located in the canton of Aargau, holds a concession until 2075. The SBB recently invested five million Swiss francs in environmental measures around the facility. During the incident, the newly renovated bypass channel for fish was completely dried up for several hours, blocking both upstream and downstream fish movement. Water organisms such as fish, crustaceans, and insects were affected, with many dying as a result. The local fishing association has submitted a formal complaint. Despite efforts to restore water flow after the disturbance was noticed the following morning, the fish could not be saved. Officials from the Canton of Aargau were present on site, according to Roschi. They considered emergency fish removal, but it was too late. “Unfortunately, it was already too late,” he says. Based on images, the fishing association estimates that hundreds, possibly thousands of fish perished during the incident. A pedestrian discovered the dead fish and alerted the police. However, counting the exact number proved difficult because the dry streambed was later flooded with large amounts of water. A key part of the bypass channel at the Aare power plant is a 770-meter-long, nature-friendly side stream that connects the existing bypass channel with a branch of the Aare. Images from the fishing association show this stream was left dry after the incident. The SBB responded to inquiries from SRF stating that they informed the relevant authorities promptly upon discovering the issue. “We deeply regret what happened. It was a technical fault,” says media spokesperson Sabrina Schellenberg. The cause of the technical failure remains unclear. The Rupperswil-Auenstein power plant operates automatically, like many other river power plants in Switzerland. This has been criticized by the national fishing association. “Previously, these power plants had staff on-site. Such incidents occur repeatedly nationwide.” A similar incident occurred on July 28th along the Albula River, where thousands of fish died due to a sudden drop in water levels below the Sils power plant in the Domleschg region. The operator of that plant is the Zurich City Electricity Works.