15th June 2017One of the most rewarding aspects of the work we do is witnessing the benefits that can result from our work. Working on the recovery of rivers can often be an uphill struggle, with positive changes taking time to manifest and come to the fore. This isn't always the case however and a recent project that we have been heavily involved in has displayed some positive changes almost from the point of inception.
The site is on the River Cam, just outside the centre of Cambridge. Fishtek were commissioned by Cambridge City Council to design (both the outline and detailed construction design) a new natural bypass channel, with the aim of improving fish passage in the River Cam. Working with Cambridge City Council and the EA, Fishtek proposed a design utilising a clever automatic upstream flow control structure to vary flow into the pass, with the channel downstream of this point formed as a natural bypass channel of timber beams, rocks and gravel (built by Five Rivers). A couple of images of the final pass are shown below (all images courtesy of Ellis Selway, EA):
Although the pass currently looks a bit 'raw' with the bare ground exposed, that will quickly re-vegetate and the final structure will blend into the landscape. Within days of the pass being opened, fish were seen using it, including eels. More recently, dace and minnows have been seen using the pass, as well as some very large chub! An image of these is below (the dark grey splodges in the pic). This is all fantastic news and bodes well for the future performance and use of the fish pass.
27th April 2017We have been heavily involved in the large 'Unlocking the River Severn' project, spearheaded by Severn Rivers Trust and the Canal and Rivers Trust, for the last couple of years. Aimed at restoring runs of shad to the River Severn, Fishtek have worked with Arcadis to deliver the designs for several large fish passes on the navigation weirs on the lower Severn. Once installed, these will enable shad (which are currently prevented from migrating up the river) to return to their native range.
As an additional part of the project, we have been commissioned to install a fish counter at a tidal weir below where the first fish pass is proposed. Earlier this week, one of the Severn Rivers Trust team Tim Thorpe took this fantastic footage of a twaite shad going up over the fish counter. Heartening to see and hopefully a portent of things to come up the entire length of the river in the future.
30th March 2017
We continue to work closely with the Environment Agency and JacksonHyder to deliver various fish passage projects and we are excited to provide a further update on this successful collaboration.
Our Senior Engineer, Mike Lakin, recently went to view Gretton Weir fish pass on the River Wellend in Northamptonshire. The fish pass was designed by Fishtek Consulting and built by JacksonHyder on behalf of the Environment Agency. It comprises a single flight of Larinier fish pass and three notched pre-barrages, as well as a separate eel pass for the upstream passage of critically endangered European eel. The site visit allowed for us to check that the fish pass was functioning as designed and also gave us a chance to capture a few photos. The fish pass has significantly improved habitat connectivity at the weir, which was previously a significant barrier to all upstream migrating fish.
10th March 2017Last year we posted about the design and construction of Stony Startford bypass channel on the River Great Ouse, Milton keynes (http://www.fishtek.co.uk/news.php?page=CgkIBRjg3dyezCoQr8HftqXN8pJ1). Drone photography has since been used to capture the channel and we are pleased to see it has become well established with wildlife and vegetation. Bypass channels are an excellent 'close-to-nature' fish passage solution that aim to replicate a natural channel. As well as re-connecting existing riverine habitat additional habitat is created that can provide refuge to fish and promote biodiversity for other species including birds, mammals and invertebrates.
It has been a while since our last news update! Partly because we have been busy carrying out all kinds of fishy work and partly because our twitter account has taken over as our regular news bulletin. Please follow us for regular updates of our work: https://twitter.com/fishtekconsult
For the last year or so we have been working closely with Jacksonhyder to deliver the fish passage element of the TWGR (Thames Weir Gate Replacement) project, an Environment Agency project that aims to update weir gates on the River Thames and install best practice fish passes. We reported on the completion of the eel pass at Caversham weir last year, which is a novel eel passage solution designed and fabricated by Fishtek that has been installed alongside the updated sluice structure. Further information about Caversham can be found here: http://www.fishtek.co.uk/news.php?page=CgkIBRihk-Ky0yoQr8HftqXN8pJ1.
The second of three sites has since been complete and our Senior Engineer, Mike Lakin, recently went to view the works. The sluice gates at Cookham weir have all been updated and Larinier fish passes have been installed in place of the gates at either end of the weir. The fish pass on the true left bank also contains vertically mounted eel tiles to allow for the upstream passage of European eel. The fish and eel passes were designed by Fishtek as a series of discrete aluminium units that could be assembled on site and lifted into position. This method negates the need for within channel concrete works and the requirement to transport large objects. The main body of the fish pass is formed from a series of aluminium sheets that have been bolted together using webbing plates. Internal struts have been used to strengthen the structure and flanges have been installed to create water tight seals where required. It is a simple and cost effective solution that significantly improves habitat connectivity for migratory species and resident (non-migratory) fish. Along with other works being undertaken within the Thames catchment, the fish passes at Cookham weir contribute to meeting objectives of the Water Framework Directive and will aid with the recovery of the fishery of the wider Thames catchment.
Combined Larinier fish pass and eel pass on the true left bank (viewed from downstream)
Combined Larinier fish pass and eel pass on the true left bank (viewed from upstream)
Larinier fish pass on the true right bank (viewed from downstream true left bank)
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