Hexham Fish Pass is a project that will significantly benefit the long-term ecology of the River Tyne for current and future generations. Situated on the River Tyne in Northumberland, Hexham Fish Pass is a two stage fish ladder which facilitates the migration of salmon and coarse fish past a high weir to their upstream spawning grounds. Set against the backdrop of an iconic 220 year old stone bridge, this project realises the aspirations of the many project stakeholders and addresses the resultant engineering challenges of working within a major river.
In May 2016 the Hexham Fish Pass received high commendation at the prestigious Robert Stephenson awards for the £0.5-£4m category.
Background and Introduction
The bridge crossing the River Tyne at Hexham is founded on a series of wooden piles on a sand and gravel riverbed. The weir adjoining the bridge is the most significant impediment to fish movement on the Tyne* * – even during normal flows. The watercourse of the River Tyne is very dynamic due to environmental and human induced factors. As a result, scour of the downstream reach has occurred. This has resulted in significant water level drops at low flows; posing a significant challenge to fish migration. A fish pass was previously installed in the 1960s; however this has become less effective in low flows. With scouring predicted to continue and potentially impact the ecology of “England’s best salmon river” the Water Framework Directive dictated the clear need to consider options to avert these issues. Environmental offsetting from the second Tyne Tunnel project, channelled through TROOA and the NECA, and the emergence of the TRT as the river’s guardian brought together a suitable funding package. The bridge custodians and project client, NCC, also identified necessary repairs to the southern section of the apron. BT Bell, who were involved from early conceptual stages, were appointed to undertake a feasibility study to support a suitable design for a low water fish pass. This included significant research into river levels/flows in hydrological reports, analysing potential locations for the pass and significant consultation with project stakeholders. This study was in conjunction with EES who managed environmental aspects. BT Bell also conducted the design of the fish pass, including new sheet pile wall and catch arms.