Oakenshaw weir is the first of two large weirs on Hyndburn Brook which pose a barrier to fish migration. The 4 metre steeply sloping stone built weir face is on the main river and because of its large size it poses a major barrier to fish migration.
This weir historically provided water for the Oakenshaw Print Works, a large industrial site downstream from the weir. Once the printworks closed, the two large reservoirs the weir diverted water into were turned into landfills before being sealed and planted with trees. The weir has also been utilised for utilities and a large main sewer passes across the river behind the crest of the weir.
Due to the size of the woodland, the tight angle of the bend in the river where the weir is located and the lack of available, suitable land surrounding the weir a ‘close to nature’ bypass channel has been created to enable migratory fish to pass around the weir. This bypass channel has been created through the rough grassland on the inside bend of the river which is thought to have been the rivers original pathway prior to modifications.
An additional woodland planting scheme is now being planned which will slow the flow of rainwater, increase shade on the river and help to control water temperatures, and increase tree cover and habitat connectivity in the area.
Overall this by pass channel will improve approximately 2.5ha or 1.3km of habitat with the associated woodland improving a further 1.2ha of habitat.
High rainfall has tested the bypass channel and the 2017 electofishing surveys revealed that juvenile salmon fry have been found at the bottom of the channel which is an early sign of the channels success.