Projects

Feasibility study: Opening up the Borsteler Binnenelbe

Client: Electrabel Kraftwerk Stade GmbH & Co. KG
Project duration: 2008 to 2009

Three coal-fired power stations are planned in close proximity to Stade Bützfleht. The tidal area of the river Elbe between Hamburg and Cuxhaven is almost continuously reported as a Site of Community Importance (SCI) according to the Habitats Directive; only ports are excluded from the SCI. The power stations require large quantities of cooling water from the Elbe. Despite all precautionary measures, it is not possible to completely avoid the negative impact on species from the Habitats Directive. In particular, the Twait Shad (Alosa fallax) needs the tidal area of the Elbe as an important spawning and nursery area. Therefore, compensation and mitigation measures will be essential.

The Borsteler Binnenelbe, with a length of about 3.5km, was excluded from the influence of the tides by building a new main dike in the seventies. It is connected to the Hahnöfer Nebenelbe by two small tide gates (cross-section of each opening is 3.0m x 3.2m and length of the closed tide gate is about 50m). This tide gate is almost impassable for fish. By connecting the Borsteler Nebenelbe to the natural tideway, an additional habitat of about 20 – 50ha (depending on water-level) could be re-created and a good conservation status would be provided for the Twait Shad. Furthermore, this will have a positive impact on the other fish fauna.

The low flow areas of the shallow waters could provide retreat and nursery areas for the Twait Shad as a protected species of the Habitats Directive (Appendix II). In particular, larvae and juvenile Twait Shad prefer to stay in riparian water with low flow rates. Thanks to these measures, the primary production and, consequently, the nutritive base will presumably improve. To meet the biological goals for fish, new openings with a width of about 25m should be built in the main dike of the Elbe, replacing the existing tide gates. That would enable tidal influence on the Borsteler Binnenelbe on the one hand, and guarantee a continuous coastal protection system along the Elbe on the other. Furthermore, a parapet at a height of about 2.5m and a length of about 4,500m should be built along the south bank of the Borsteler Binnenelbe and the branch canal to the Borsteler port to control a normal tide.

In cooperation with IHP Engineering Company, Stade, ARSU was commissioned by Electrabel Kraftwerk Stade to develop a feasibility study. If this study generates a positive result (the criteria are ecological efficiency, technical feasibility and political acceptance), a planning approval procedure for the ‘Opening Up of the Borsteler Binnenelbe will follow immediately.