The Court of Appeal has allowed an appeal by the Environment Agency against a High Court judgment which indicated that it may be liable for the effect of the operation of a fish pass on a nearby hydroelectric turbine. The Environment Agency has a statutory power in s 10 Salmon and Freshwater Fisheries Act 1975 to install and maintain fish passes in connection with weirs and other obstructions in rivers, to allow the passage of migratory fish such as salmon. In Pigot v Environment Agency the Claimant, who owns and operates a hydroelectric turbine on the River Kennet, sought declarations that the Agency was liable to him in nuisance due to the diminution in the flow of water through the turbine as a consequence of the operation of a fish pass. The Agency argued that it benefited from a defence of statutory authority. That argument was rejected at first instance ( Env LR 25).
On appeal, the Court of Appeal found that whilst the Agency did not have a general defence of statutory authority where the installation of a fish pass injured the Claimant’s turbine, it did have a defence in circumstances where the injury arose only through the installation of a new turbine, after the fish pass was installed. On the facts, that was an answer to the intended claim in nuisance.
The judgment is available here: Pigot v Environment Agency  EWCA Civ 213.