At last – full speed ahead for fish: the fish bypass at the Mühlenschleuse sluice at Großer Burstah has now been completed, enabling fish to pass unhindered from the Elbe river system to the Alster and its tributaries. For the first time in years, fish such as sticklebacks, eel and sea trout – and later even salmon – can now, once again, reach the Alster, find feeding biotopes there, and spawn. Three further fish bypasses are to be constructed in the upper reaches of the Alster by 2019.
Senator for Environment Jens Kerstan declared during the opening ceremony of the fish bypass “At long last, fish can once again pass freely from the Elbe to the Alster. The Mühlenschleuse sluice is an important element in a series of fish bypasses now stretching from the Town Hall Sluice to the sluice at Fuhlsbüttel. Our aim is to create near-natural rivers as a basis for species-rich life communities that are typical for these waters. I am delighted that the fish ladder at the Mühlenschleuse sluice has now been completed, representing an important step.”
The Agency of Roads, Bridges and Water (LSBG) was commissioned by the Ministry for Environment to construct the fish passage, which cost €1.5 million. “The limited space available at the construction site for the fish pass presented a major challenge. Nonetheless, the fish bypass was successfully installed as planned,” stated Olaf Müller, Division Manager of LSBG.
Located at the side of the Mühlenschleuse sluice, the fish ladder enables fish to bridge a height difference exceeding two metres, depending on the tides, over several stages. They are raised by a leading flow that enters the system. The fish manage to migrate upwards via a series of connected troughs through which water flows. The slotted walls between the basins are arranged so that there are rest zones within the troughs where the water is calm. Further sluices are to be redeveloped and made passable for fish by 2019.