DE
Due to deficits in the existing fish ladder at the Kostheim hydropower plant on the River Main, this was optimised in cooperation with the Federal Waterways and Shipping Administration. For this purpose, we were commissioned by our client to construct an additional fish ladder close to the turbine outlet of the hydropower plant. The water volume from the inlets was increased via a doping channel in order to improve the fish pass's accessibility. We provided services in the fields of structural engineering, hydraulic engineering and specialised civil engineering.
The structural and hydraulic engineering work on this project was particularly challenging.
After an approx. 2,000 m² construction pit shoring, which was carried out on the land side due to the immediate proximity to the Main, the groundwater was lowered by means of lowering and expansion wells. This was followed by the approx. 5 m deep excavation pit and the reinforced concrete work for the approx. 4.5 m high doping channel.
It was necessary to attach watertight shoring boxes (so-called swallow nests) to the bank wall for the new fish entrance or inlet to be built. The shoring boxes were prefabricated from sheet piling profiles on land, lifted into the Main and connected to the existing bank wall or river bed using divers and sealed to create a watertight excavation pit. Subsequently, 2 openings, each 30 m² in size, were cut into the bank wall below the water level of the Main, consisting of an overcut bored pile wall, in order to carry out the reinforced concrete work for the access and inlet structures.
