Rivers in the Eden Valley contain numerous old weirs which were built for historic reasons, such as powering mills, raising river bed levels or redirecting water courses. Nowadays, many of these are redundant and can pose a maintenance and liability issue for their owners.
Weirs also alter how natural rivers behave, creating a ponded section upstream of the barrier and changing how gravel moves down the river. This not only adversely affects the wildlife habitat, but can also change erosion, deposition and flood risk, all of which may be a problem for people and property.
They make it difficult for fish to feed and breed. The River Eden and its tributaries support a number of fish species which need to move up and down rivers to feed and breed. Some fish only migrate a few hundred metres whereas others, such as Wild Atlantic salmon and eels, must travel thousands of kilometres. Their journey within rivers can be impeded by man-made barriers such as weirs, culverts, bridges and dams.
All reduce the likelihood of fish being able to move freely to find food, hide from predators and successfully breed. This threatens the continuing survival of these species.
Weirs and other barriers within rivers raise the level of the river bed, alter how gravels move through the river system and make it difficult for fish to move up and down the river.
At Eden Rivers Trust, we support the removal or modification of weirs to help return the river to a more natural state. This benefits both communities and the environment – more natural rivers have diverse habitats which support a range of insects, fish and other wildlife. They function in a more sustainable way and are more resilient to climate change. They can also enhance the landscape and enjoyment of the countryside.
Removing weirs allows the river to shift and store gravel more appropriately and creates the range of features such as gravel beds and bars, riffles and pools which river wildlife needs to survive. It also enables fish to move freely as water levels fall or rise.
Removing barriers such as weirs is just one of a wide range of techniques we use throughout the Eden catchment that restore natural processes to rivers or help existing natural processes work more efficiently. We look at the catchment as a whole, not just the immediate area, in order to research, design and implement appropriate techniques that address the local problem without adversely affecting the rest of the river course.
How you can help
Weirs are dangerous places – they have fast-flowing currents and deep water. If they are falling into disrepair, they may have obstacles hidden under the water. Don’t play or swim near weirs.
If you notice a problem with a weir, please notify Environment Agency on 0800 80 70 60