On Stream has been involved at Huckworthy Hydro on the river Walkham for many years. Our services include design services during scheme development, license compliance work, ecological programme coordination, interpretation and presentation.
At the design stage the system had to pay due regard not only to the historic aspects of the old mine leat and surroundings in a National Park, but also to fish protection measures, which included fine inlet screens, automated egress arrangements, fish pass facilities with recording facilities and automated outfall screening. In addition the abstraction regime is specially designed at the site to provide enhanced flow variability at times of fish migration. All these aspects required careful design and careful operation, and the licenses issued include arrangements to validate the efficacy of the arrangements.
This site includes a 1km deprived reach with migratory fish present, and therefore it was vital that any license granted included robust conditions, and this requires annual ecological work, characterising fish behaviour and passage past various aspects of the scheme. This includes monitoring the fish pass which was built on the old weir as a mitigation measure, as well as monitoring the inlet and outfall areas, and the health of the depleted reach. This is completed largely via underwater recording and annual analysis and reporting. Further electrofishing and expert visual observation is employed, which is coordinated by On Stream and presented annually.
In addition On Stream provides complete asset management to the site, including site support, statutory reporting to EA and OFGEM and emergency response.