Durham Hydro – Update.

20 Oct

During the current season (2019) the number of migratory fish trying to enter the Archimedes screw chamber seems to have declined. This is in no small part due to the operators Durham County Council, to there credit, turning the screw revolutions down during the period May till the end of October. This has reduced the white water at the base of the screw providing less of an attraction to migrating fish. Although during periods of high water fish have still been using the Larinier fish pass at the side of the screw.

There does not appear to have been any significant fish mortalities this season and it is believed that the operators have still been able to generate sufficient energy to meet their needs.

The protective flaps over the chamber also appear to have worked and it is anticipated that these will be lengthened in due course as a further preventative measure.

Along with these measures the Environment Agency have commissioned an independent report from a company specialising in the design of fish passes. The report highlights flaws in most of the existing Framwellgate fish passes with recommendations and costs on how to rectify matters.

With the EA still under austerity controls, only limited funding is available and the EA have decided to bid for 2020 funding to improve fish access to the lower weir near to the Archimedes screw, one of the reports principal recommendations. This will entail using stop logs to reduce the flow through the central notch and diverting water to the notch in the weir adjoining the screw which will also be reduced in depth and widened to create easier access. At the same time work will be undertaken to the base of the Larinier fish pass to create more white water in an attempt to draw fish away from entering the screw chamber.

Everything depends on funding of course so let’s hope it happens.