Recommendation in the spotlight: Removing weirs from streams and rivers, the challenge for watercourse management
A lot of weirs fragment our streams and rivers into numerous smaller sections. They were built, among other things, to turn mills, generate hydropower, make watercourses navigable, and regulate water discharge.
For nature, the consequences of impoundments are great: the habitat for the aquatic fauna and flora deteriorate as free-flowing rivers turn into monotonous watercourses with almost stagnant water during periods of low discharge. Fish can no longer migrate freely or die in the hydropower turbines, sediment transport is disturbed, water and sediment quality deteriorate... Partly because of this, very few Flemish watercourses are in good ecological condition.
Good water quality is not enough for aquatic plants and animals to flourish again. The importance of good habitat quality in this respect cannot be overestimated. Removing weirs from our streams and rivers is a drastic but necessary measure to sustainably restore watercourses. That is why the EU Biodiversity Strategy 2030 set the target of restoring at least 25,000 km of rivers by removing barriers by 2030 at the latest.
>> Read the full Recommendation (in Dutch)
image above: simulation of a built-in fish lift in the Velpe near the Arnauts mill (© www.vislift.nl; simulation: Duquennois & Schrijer, 2023)