The programme “Rhine 2040” aims at restoring the ecological continuity of the Rhine from Lake Constance to the North Sea and that of priority tributaries for recolonization. This target was developed in detail in the “Master Plan Migratory Fish Rhine”. The “Habitat Patch Connectivity Rhine” equally aims at restoring ecological continuity.
Once the connected habitats of the Rhine and its tributaries present an ecological continuity, animals may move up- and downstream and plants may be carried away by the currents. After eventual extreme situations, such as floods and low water periods, they may recolonize up- or downstream sections from lateral waters. Therefore, ecological continuity is a very important functional characteristic of the Rhine ecosystem.
Transverse structures, such as pipings and conducts, weirs or barrages may seriously interfere with or completely obstruct migration in a water body. This may particularly be demonstrated on the example of migratory fish species, which, for the purpose of reproduction need to migrate between the headwaters of freshwater bodies and the sea. Bypass rivers, fishways or fish passes may maintain or improve ecological continuity at barrages.
That fish may migrate upstream the Rhine and into the Black Forest River Kinzig?
This is possible, since the fish passage at Gambsheim was accomplished in 2006. The ICPR programme „Rhine 2020 – Salmon 2020“ aims at restoring the continuity of the Upper Rhine for fish as far as Switzerland.