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Pilot Project: Dörverden Fishway

The European Water Framework Directive (EU WFD) obligates Germany’s Federal Waterways and Shipping Administration (WSV) to maintain or, where needed, restore ecological connectivity at dam structures along federal waterways. Therefore, the dam structures are to be retrofitted with upstream and downstream fishways. As migration corridors to smaller bodies of water, federal waterways play a particularly important role for fish such as salmon, eel, burbot, and barbel.

In a nationwide prioritization concept, the Dörverden barrage was selected as a pilot site to investigate fundamental questions about the effectiveness of upstream fishways on the migration flows of fish. Björnsen Consulting Engineers is designing and planning the construction of the new fishway at the Dörverden barrage, with technical support from the Federal Waterways Engineering and Research Institute (BAW) and the Federal Institute of Hydrology (BfG). Special requirements are posed by the confined spatial conditions in front of the power plant, the relatively large underwater fluctuations, the control of the necessary water dotation, and the measuring and counting devices for the BfG/BAW’s scientific monitoring program.


  • Planning for a fishway in the existing dinghy lock
  • Planning of a collection gallery to connect the right bank and outlet area of the HPP to the fishway.
  • Planning of the bank access point (right bank)
  • Variable dotation up to 8 m³/s and variable opening of all entry points
  • Planning of extensive facilities for the BfG and BAW R&D monitoring project (fishweirs, VAKI counters, DIDSON sonar, telemetric detection of ascending fish, holding basins, etc.).

Key Data

  • Weser near Dörverden, river km 308.832                      
  • 3-field weir, mean fall 4.0 m
  • Full supply level at headwater: 14.60 mNN
  • Water level W30 at tailwater: 10.30 mNN
  • Water level W330 at tailwater: 12.67 mNN
  • Mean flow (MQ): 198 m³/s
  • Hydroelectric power plant (HPP): 176 m³/s; 4.2 MW

Our Services

Project planning and structural engineering for phases 1–6, feasibility study for mobile collection gallery, geotechnical report, technical equipment for water dotation and fish counting, EIA preliminary examination, LCP, technical appraisal under species protection law, hydrological-hydraulic studies and verifications (analytics, 2D, 3D), health and safety coordination


Wasserstraßen-Neubauamt Helmstedt
Walbecker Straße 23 b, 38350 Helmstedt