ABSTRACT
At the 16th Rhine river Ministerial Conference on February 13, 2020 in Amsterdam, a new “Rhine 2040” program was adopted. One of the objectives of this program is to complete the restoration of fish continuity between the North Sea and the Schaffhausen falls, a restoration initiated during the Rhine 2020 program with the commissioning of fish passes on Strasbourg and Gerstheim EDF Hydro run-of-river plants.
To do this, two fish passes have been included in the “France Relance Plan” in September 2020 and are in progress: one on Rhinau Hydropower scheme and another one on Marckolsheim Hydropower scheme. These run-of-river hydropower systems each consist of a dam and a diversion canal equipped with shiplocks and a hydro plant. In order to guarantee fish attractiveness, passes are installed downstream of the plant in the tailrace canal and designed to be non-selective with respect to fish species.
The two ‘twin’ fish passes for Rhinau and Marckolsheim sites, designed by EDF engineering teams, in consultation with local NGO’s, the French administration and river foreign stakeholders (Germany, Switzerland), consist of the following structures:
8 entrances distributed on the left bank and on the right bank of the tailrace canal, allowing adaptation to river flowrate or level conditions to make the pass as best attractive as possible;
An attraction flow of 15 m3/s delivered by pumps or turbines depending on the banks;
A bank-to-bank fish conveying bridge-canal 120 m long allowing fishes to be collected on the right bank;
A series of basins allowing to pass the plant’s head (12 m) and upstream levee up to the headrace canal.
It should be reminded that EDF had initially proposed to study and implement an innovative solution on Rhinau scheme, based on a fish capture-transport and floating barge system, in order to guarantee the deadline for the restoration of fish farming continuity on the Upper Rhine in 2020. This proposal was ultimately not selected by the Authorities.
Fish pass works at Rhinau Hydropower site started in 2022, with a target completion date of 2025. The provisional timetable for Marckolsheim site is 2022-2026.
These major environmental measures and structures will improve fish migration conditions while adapting to the operating conditions of the Hydropower schemes.
