Thetford, a small market town in Suffolk, features an important crossing of the Little Ouse River and a large sluice gate structure which controls its…
Eel Passes – Fully tailored packages
- Modular eel passes allowing installation around any structure
- Proven design, developed with nationwide experts
- Robust, long lasting construction
- Customisation available if required
- Survey, design liaison and installation all part of the service
Historically, water control structures such as weirs and pumping stations prevent a barrier to the natural migration of eels and elvers. Causing declining numbers over recent years. ACE has worked tirelessly with nationwide experts to develop a range of passage equipment to reduce the impact of the installation of our flow control equipment. In turn, this naturally lead to ACE being employed nationwide to advise and supply eel passes around existing and new structures.
Elvers have a natural instinct to seek out fresh water, having started life in the sea. When they encounter a barrier, they attempt to migrate upstream. For instance via wet grass, leaks in structures and other sources of fresh water. This has been hampered in recent years following improvements in seal designs on sluices, removal of vegetation and urbanisation. However, the installation of ACE eel passes can reduce this decline. By simulating wet grass and providing an attraction flow, elvers can find a safe route to continue their journey inland.
Our eel passes follow a fairly simple concept to use elver’s instincts to attract and promote safe passage:
- Suitable climbing substrate, and a flow to keep it moist (usually HDPE channel, with brush substrate of a suitable pitch)
- A point of no-return at the highest point (to ensure safe passage)- typically a splitter box
- Swift, smooth descent to flush eels into the upstream watercourse, away from seaward flow
Although the concept is simple, the delivery can be complex due to obstructions, traffic routes and existing services. a modular, proven concept, which allows the systems to be unobtrusive and work with minimal disruption is often used. Updates and modifications to the eel passes accommodate particular requirements to suit sites. Whether this includes provision to trap and monitor eels, provide public interaction facilities for education, or additional security to prevent vandalism. We can assist.