Skip to main content

Weirs tha bin?


Admittedly, the pun in the title only works if you are familiar with South Yorkshire dialect. However, the industrial North has a particularly large selection of barriers to fish movement in the form of artificially engineered weirs. These affect all gravel spawning species of fish (from barbel, grayling and trout throught to the big hitters of the migratory reproducers; the eels and salmon). In addition, all barriers to movement (including weirs) reduce the ability of fish to avoid pollution incidents and/or subsequently return to their home patch. Moreover, the impoundment of water behind weirs increases the siltation by reducing current speed (sometimes for surprisingly long distances upstream of the structure - depending on weir head height and stream bed slope). Increased siltation is obviously not good for spawning gravels. Regulated slow flows also tend to homogenise the habitat in the impounded reaches, resulting in lower variety of invertebrates and fewer good holding features for fish. The fish that are present in the slower water are often very difficult to approach without spooking them in the flat water. However, it is almost universally true that the pool downstream of the weir (where the water rushes in providing oxygen, cover and more variable/interesting habitat) will be an excellent fish holding area. Therefore, in removing such barriers, you are often asking anglers to take a great leap of faith that the resultant overall improvement will be worth it. To those people, I would ask if I could take you fishing in pocket water this summer and lets see what we catch relative to our results in the canal-like sections.
The report I'm reading at the moment details plans to tackle the 24 weirs on the 8km of the River Sheaf (a tributary of the S. Yorks Don). The tributaries of the Sheaf itself house a further 20 weirs of their own. I read somewhere that the main river Don used to have something like 300 plus weirs - but that these days there are somewhere around 30 weirs on the main river that represent a "significant barrier" to fish movement.
P.S. the title translation would be "Where have you been?" rather than an enquiry as to the location of a waste receptacle.

Comments

Popular posts from this blog

First Survey Record of Wild Trout Returning to Lyme Brook Habitat Works Site!

You may have seen the first three phases of works on the middle reaches of the Lyme Brook (shown in previous blogs Here and Here) from project works that began in 2015...

Well although the first surveys after that work found some nice coarse fish populations - there was no cold hard evidence that any trout had found the newly-improved habitat...Until now!
I received a phone call today from Matt Lawrence who is the EA's Catchment Host for the Trent Valley Catchment Partnership (with key partners Groundwork West Midlands and the Wild Trout Trust who conceived and delivered the habitat works). Matt told me that he'd had some exciting preliminary reports from a EA Midlands fisheries surveys team. Their survey on 7th September had caught several wild trout as part of their sample on the habitat works site.
These are the first modern records of trout in the brook and is also the exciting news that we have been waiting for on these first phases of work to create spawning, juvenile an…
Catching and Releasing the first Fly-Caught wild trout from a stream that was dug out of a city-centre pipe was probably the highlight of 2016 for me!

Buried in a brick tunnel under England's industrial developments of the 1800s, a section of the Porter Brook in Sheffield was brought back to the surface by a bold project co-ordinated by Sheffield City Council and involving the Wild Trout Trust, The Environment Agency and many more partners.

You can now witness the actual process of freeing the Brook from its pipe - and the creation of functioning trout-stream habitat in this short video.



Yet, the above video does not show the completed park that was a huge part of the entire project - and it does not show the planted vegetation beginning to develop in the summer of 2016. And, it does not show any fly fishing or video of a trout capture...

But the film, below, that was made by the excellent Huckleberry Films as part of the Canal & Rivers Trust "Living Waterways" awar…

A previously buried section of stream produces the first fly caught trout in >160 years

As near as I can work out from the archaeology report, this section of river - recently brought back to the surface in dramatic fashion by Sheffield City Council, the EA and the WTT partnership - was buried in a low brick tunnel somewhere around 1853 to 1868. The northern half of the site was certainly buried underground BEFORE the time the 1853 map was produced....and the rest of the brick tunnel was placed over the top of the stream before the map of 1868...

Of course, it is not easy to tell what the water quality was like in that section even BEFORE the stream was buried...and whether there were trout surviving in the stream when it was sealed underground...

What is damned sure is that you couldn't wave a fly fishing rod around in that underground tunnel once they'd built it!

This was still the case until the completion of the massive project to remove the brickwork and create an attractive "pocket park" in the city centre. You might have seen from This Previous …