This January, Colne Valley Regional Park completed the construction of an innovative fish channel, known as an Eel & Fish Pass, to resolve the migration issues of eels and other fish in the Colne River in Denham.
The aim of the project was to help improve the conditions of an endangered species and deliver significant environmental benefits, and with the help of a £25,000 grant from Grundon, via the Landfill Communities Fund, the project kicked off in September 2022.
The Colne River, like many British rivers, features a weir (a small barrier built across the river) to control the water level upstream and mitigate flooding, akin to a small-scale dam. Unfortunately, these massive barriers prevent eels and other fish from migrating upstream and reaching vital habitats for their development. The number of young European Eels has dropped dramatically since the 1980s and they are now classed as ‘Critically Endangered’.
Fortunately, the successful installation of Eel & Fish Passes in Denham has made it possible for eels and other fish to swim upstream past man-made weirs and allowed them free movement to reach the next stretch of the river. Grundon is delighted to have helped fund such a crucial environmental development to help protect and support the healthy migration of European Eels.
Colne Valley Regional Park has been an ideal habitat for eels for thousands of years, with over 200km of rivers and canals and over 60 stunning lakes. European Eels migrate over 3000 miles from the Sargasso Sea to European freshwaters for most of their adult life: enjoying the bountiful wetland habit of the Colne River Catchment and its abundant sources of food. Eels depend on transatlantic currents to carry them across the ocean to our shores and use the tides of rivers to carry them upstream, but once they arrive at non-tidal sections, they’ll have to swim to the next leg of their journey.
Working hard, ‘eeling great!
To ensure the eels and fish could transverse the weir at Colne Valley Regional Park, a simple and effective modular Eel & Fish Pass was installed. The modular Eel & Fish Pass involved mounting tiles onto the edge of the weir, enabling eels to navigate the structure with minimal impact and disturbance. These tiles are textured with a special climbing substrate, providing travelling eels with a brush-like grip to transverse across the structure. This low-impact solution requires low volumes of water to follow through the eel passage frame, calculated carefully to ensure minimal disturbance of the landscape or hindrance to the weir’s primary purpose.
The Eel & Fish Passes were continually monitored throughout their construction and did not significantly alter the flow of water over the weirs, resulting in no increase in the river’s flood risks. Additionally, there was minimal damage to the local environment, only one tree was removed to enable access to the site and was promptly replaced with another, and the Park’s walking routes and thoroughfare were kept accessible as normal.
Pontoon installed in the river
Installation complete
/
Colne Valley Regional Park aimed to provide a sustainable solution to resolve the urgent migration issues affecting critically endangered European eels and as a supporter of the project, we are thrilled to see the river’s ecosystem thriving as a result. The eel passes have increased the number of freshwater eels and fish upstream and encouraged high species diversity, promoting the health and enjoyment of the river’s local wildlife and Colne Valley visitors.
Grundon is committed to supporting environmental conservation and has donated well over £5million to a wide range of environmental and community projects across the South of England, via the Landfill Communities Fund.
Find out more about Colne Valley Regional Park’s Eel Passes or contact enquiry@colnevalleypark.org.uk
