Constructing the country’s largest fish pass

Delivered on behalf of the Environment Agency, the £12m scheme involved the construction of a 200m long, 6m deep and 6.5m wide fish pass, enabling a wide range of species such as salmon, trout and eel to safely bypass the Holme Sluices structure and access spawning and feeding grounds further upstream.

Holme Sluices is a key component of Nottingham’s flood risk management infrastructure, originally constructed in the 1950s as part of an extensive flood defence programme. The structure crosses the River Trent and plays a vital role in controlling water levels on either side of the sluices to reduce flood risk in the city. However, the difference in water levels upstream and downstream has historically created a barrier to fish movement, preventing many species from travelling freely along the river.

The Colwick Fish Pass is divided into 20 ascending chambers into which water flows through narrow slots. Fish of all species swimming upstream to lay their eggs in the gravel riverbeds of the Trent tributaries such as the River Dove and the River Derwent will be able to pass through these slots and rest in the chamber above before continuing.

We supported the project by specifying and supplying a Bubble Curtain, which formed part of the site’s environmental protection measures during the build.