Fish passages
Although a large number of fish passages have been constructed, migrating fish still encounter a large number of obstacles.
Current situation
Migrating fish encounter a large number of obstacles in the water, for example closed-off inlets, weirs and hydro-electric power stations. "Fish passages" (also known as "fish ladders" or "fish ways") are constructed to enable them to overcome these barriers. A large number of such passages have now been constructed in the Netherlands and more are planned. Most of them are located in the east of the country, mostly in brooks. There are also fish passages in the major water bodies, for example at the weirs in the Lower Rhine/Lek and the Meuse and at the locks in the Afsluitdijk (the causeway separating Lake IJssel from the sea).
Fish passages are often only installed when weirs are undergoing maintenance or being replaced; this means that it may take a long time before the whole water body is suitable for migrating fish. The weirs at Hagestein and Amerongen on the Lower Rhine/Lek still do not have any fish passages; nor do those in the Meuse at Grave and Borgharen. In the case of the Afsluitdijk, very little account is yet taken of fish movement into the Lake IJssel. As of 2005, the outlet sluices for the Haringvliet dam will be left ajar.
Regional water bodies still have thousands of weirs that are not shown here. According to information provided by the water boards, only a few brooks are completely or almost completely accessible to migrating fish.
Policy objectives
The Third and Fourth Memorandums on Water Management (Derde/Vierde Nota Waterhuishouding) include the objective of restoring the migration routes for salmon and eel in the Rhine and Meuse by 2000. The 13th Ministerial Conference of the Rhine States in 2001 adopted a programme for sustainable development of the Rhine; one of the objectives of the programme is to make it easier for fish to migrate.
One of the objectives of the Policy Decision on Freshwater Fisheries (Beleidsbesluit Binnenvisserij) taken by the Ministry of Agriculture, Nature Management and Fisheries is to optimise the routes for migrating fish in inland waters. No specific targets have been set, however, for the number of weirs or the length of the rivers along which fish will be able to migrate.
Technical note
The map shows the location of the main saltwater/freshwater transitions at which a sluice constitutes an obstacle for migrating fish. The weirs in the major rivers are also shown, together with the number of weirs where a fish passage has been constructed. Existing and planned fish passages in regional water bodies are also shown. In the case of small water bodies, several dozen more fish passages are planned than are shown on the map.
References
- Kwaadsteniet, P.I.M. de (2000). Vismigratie boven water. In: Themadag Vismigratie boven water. Organisatie ter verbetering van de Binnenvisserij. Nieuwegein.
- LNV (1999). Beleidsbesluit Binnenvisserij. Ministerie van Landbouw, Natuurbeheer en Visserij. Den Haag.
- RIVM en DLO (2001). Natuurbalans 2001. Milieu- en natuurplanbureau. Kluwer. Alphen aan den Rijn.
- V&W (1989). Derde Nota Waterhuishouding. Water voor nu en later. Ministerie van Verkeer en Waterstaat. Den Haag.
- V&W (1998). Vierde Nota Waterhuishouding. Water kader. Regeringsbeslissing. Ministerie van Verkeer en Waterstaat. Den Haag.
- V&W (2000). Besluit beheer Haringvlietsluizen. Rijkswaterstaat HK/AW 2000/81. Ministerie van Verkeer en Waterstaat. Den Haag.
