www.managingwater.co.uk Fish Passes & River Structures
MIKE HUMPHREY, GLEVUM PR
A Helping hand for the Eels and elvers
The critically endangered European Eel, which has seen its numbers sink dramatically over the past 30 years, has been passed a lifeline by the Environment Agency which has recognised the necessity to assist these creatures back into their home territory. All European eels share the only known spawning ground in an area of the Sargasso sea, south of Bermuda. Eel larvae follow the Gulf Stream and North Atlantic Drift to return to Europe metamorphosising into glass eels when they reach the continental shelf. Glass eels are attracted to freshwater and enter UK rivers in spring, historically in great numbers After an average of six years for males and nine years for females, eels mature, stop feeding and become silver in colouration. Silver eels swim downstream towards the sea
to begin the long migration of 5,500km back to the Sargasso Sea, where they spawn and die. CW Engineering have employed their own knowledge plus the industry’s best technology to create
a method to assist the eels & elvers in their migration. A 150m long eel and elver pass has been installed at the mouth of the Great Ouse, helping their migration around the major flood control sluice at the river’s tidal limit.
to close the pipe through the flood wall. The cabinet allows for retro-fitting of camera equipment and cabling. Now it’s all downhill for the elvers through another HDPE plastic pipe which exits into the fresh water of the Great Ouse. A number of
The pass is in 4 stages, by-passing a sluice where the tidal range can exceed 6 metres: On the salt water side there is an ACE recycled plastic eel ramp with brushes fitted to assist ascent. This is followed by an HDPE plastic pipe with ACE spiral elver brushes which runs underground.
At the highest point there is a secure galvanised cabinet housing a 2 way pump which assists the elver’s progress as they ascend and descend through the system, plus flow adjustment stopcocks and ACE penstock
rodding /inspection points have been set at ground level in the pipework to allow cleaning to take place.
Due to site security and vandalism, the design and specification was modified to reduce the risk of damage to the installation. The cover was mounted on the channel at an angle of 45 degrees in order to deter vandals from walking along the tray.
Dickey Dye says this project has brought home to CW Engineering how important it is to assist these creatures with their instinctive desire for maintaining their life cycle. CW Engineering would be extremely pleased to assist in these projects utilising all it’s experience gained and developed on these types of projects
www.fadsdirectory.com
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