Improving passage for Salmon on the river Taf Fechan
This project a weir on the Taf Fechan near its confluence with the Taff Fawr. Although both rivers were essential to the Cyfarthfa Iron Works (please see the separate report of the Cyfarthfa weir project) this particular weir does not appear to be one that had been built to facilitate water abstraction. Indeed, there is evidence that at one time the river had flowed to the south of its current course. Despite erosion, over time, having worn two distinct channels, one at each side of the weir it remained an impediment to fish passage. The larger, south sided, of these channels encapsulated a deep pool which it was considered could be a basis for a form of fish ladder.
Surveys were carried out and measurements showed that four steps were needed to create an effective easement for migratory fish. A large channel was excavated in the adjacent rock and a fish pass using stainless steel bars and concrete, to form pools, was constructed. The outcome appears to be successful.
We have observed Salmon spawning in the pool below the weir over several years. However, within three weeks of the work being finished a radio tagged salmon was tracked one hundred meters above our new fish pass. The following images show the work carried out.
Construction of the fish pass
The finished fish pass