WTT Blog - Tagged with weir removal

A year has already flown by since we (me at WTT, Pete Turner at EA & Kevin Sunderland at Aire RT) worked in partnership to remove the weir at Coniston Cold on the Aire, North Yorks. I’m currently champing at the bit awaiting a bespoke permit from the EA to tackle another. The funding is in place. The owner has granted permission for full removal having seen the transformation at Coniston Cold. The next weir will present its own challenges… but more on that in another blog.

I wanted to focus on developments at the site formerly known as Coniston Cold Weir....

A WTT advisory visit in 2016 on behalf of Birdsgrove Fly Fishing Club (BFFC) to the River Dove, Derbyshire, identified seven weirs along the 5km length of river fished by the club. The impoundment of water by these structures is detrimental to river habitat, fly and fish populations,especially from a fish passage persepctive, and natural sediment transport. The advisory visit report stimulated a debate within the club about what could be done to improve the fishery and it was decided to work towards the removal of the two weirs that had been built by the club in the past.

And so it comes to pass….Coniston Cold weir, which in various forms has been a man-made obstruction to fish passage on the R Aire in N Yorkshire for the past 180 years at least, is no more. Instead, there is now 20.4km of uninterrupted free passage along the Aire and a major tributary.... and all for less than £8k!

Coniston Cold Weir: 19m wide and 1.2m headloss, with a 4m horizontal block-stone apron

I will not reinvent the wheel and spend time here discussing how weirs cause environmental issues. The evidence is abundant and simple to find in the scientific literature, and my colleague Paul Gaskell has recently summarised much of that, here. Then there are global-local events like World Fish Migration Day to raise awareness and I would wager that almost every conservation body involved with river restoration has a hit-list of target weirs on their local patch.

I’ve just had the pleasure of hosting two MSc students from Queen Mary University of London (co-supervised with Dr Chris Eizaguirre), partly for the WTT Annual Get Together, and partly to undertake some fieldwork specifically for Charlotte Pike’s project. I alluded to their research projects in a former post and now I have the pleasure of handing over to them to update you.

Charlotte’s project focuses on the use of stable isotopes to determine the success of river restoration. I will be analysing samples from pre and post intervention works against an unimpacted control site on the same river to see how the restoration has affected the ‘architecture’ of the food web. Hopefully it should be more like the control! The intervention works have been carried out by the Ribble Rivers Trust at two locations; Bashall Brook and Towneley Hall. At Bashall Brook, a riparian zone has been created where banks of the river were previously bare; essentially livestock exclusion fencing now removes the impacts of grazing and poaching. This strip of vegetation acts as a buffer to reduce nutrient run-off from farmland, keeps the ground more stable and resilient to flood damage to reduce soil erosion, and provides necessary refuge for wildlife. At Towneley Hall, a partial weir removal and a rock pass re-instates the connectivity of the River Calder allowing fish to move between formerly fragmented habitats. These interventions have been conducted to improve the quality of the habitat at these two sites, and it’s my job to find out what changes have occurred as a result!