Feasibility, design and delivery
The Tyne is the most important river in England for Salmon. Prior to our work, the the most significant obstacle for migrating fish on the Tyne was Hexham weir. Despite the picturesque sight of salmon leaping every season, salmon, trout, eels, lamprey and coarse fish were all obstructed by the weir.
In 2010 RCS commissioned a major Feasibility Study on behalf of Tyne Rivers Trust for improved fish passage at Hexham. We engaged Prof. Malcolm Newson, Elliott Environmental Surveyors Ltd, BT Bell Civil Engineers, AMR Geomatics, and Stirling University Centre for River Ecosystem Science for specialist riverbed hydro-morphological, engineering, flow hydrology, topographical surveying, and fish passage expertise.
As well as project managing the 9 month study RCS contributed to the principal environmental inputs, stakeholder and community engagement, constraints mapping, and options appraisal and presentation of solutions at this most challenging of sites.
Geomorphological survey and assessment techniques were used, together with archival investigations (old photographs, maps and oil paintings) to determine the progressive incision of the channel downstream of the bridge. This situation directly contributed to the current fish passage issues and the report highlighted that the situation will continue to worsen. Other constraints included the Grade 2* listing of the bridge and its 1771 timber foundations, an enormous range of river flows, a weir 100m wide with complex flow patterns, a potential hydro interest, as well as a number of local users including anglers, rowing and canoe clubs and public access. Fisheries and fish pass specialists from the EA were involved throughout.
Following this extensive feasibility study, the preferred solution was the construction of a supplementary fish pass in a carefully selected location. Further formal environmental assessment, EIA screening and scoping and pre-application consultations, (with engineering design provided by BT Bell), was followed by a first-time successful planning application on behalf of TRT to Northumberland County Council and fish pass consent granted by the Environment Agency Fish Pass Panel.
Once built, the fish pass was immediately used by migrating salmon and further monitoring by the Environment Agency shows that it continues to work effectively for a range of species.