26th September 2017A recent Fishtek project has involved a first for us - the use of a helicopter to install a fish pass! The pass in question was installed on the River Ness, just outside Inverness and is a temporary structure (an Alaskan A fish pass and lead-in channel) designed to enable migratory salmonids to move up and over an existing weir while works are being carried out on the weir. The pass is temporary as it is only required to be operational while work is being carried out on the existing fish pass on the weir, which will render this existing pass temporarily unusable.
The use of a helicopter was required as access to the site is very difficult. A crane could not be brought to site and the sections of fish pass were too large to lift with the machines available. It might be a relatively common sight in some parts of the world (e.g. Alaska, where this type of pass was originally devised), however it's not every day that you see a fish pass floating through the Scottish air.
|The fish pass being roped up (image courtesy of Ness District Salmon Fishery Board)|
|The fish pass being flow across the River Ness (image courtesy of Ness District Salmon Fishery Board)|
18th July 2017Technological advances mean that there are an ever increasing array of tools available for the environmental scientist. One of these is the drone, which seems to be cropping up almost everywhere at the moment.
Fishtek has recently invested in a drone, the primary intention of which is to allow us to gain aerial footage and images of sites where we have been commissioned to look into options to improve fish passage and/or design a fish pass. Getting above structures such as weirs, sluices and dams will give us a different angle to assess the barrier, as well as potentially improving the ease with which we can assess large barriers that may have sections that are difficult to access by foot.
Below is some footage shot recently at a site up in Scotland where Fishtek have been asked to look at providing the designs for a temporary fish pass. The footage shows the weir in question, as well as the current structure that fish use to pass over the weir.
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.
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