OLD PENRHIWCEIBER COLLIERY SITE
On this site a very large weir had since the shutting of the old colliery broken away from both banks creating substantial erosion on east and west banks with the possibility, if not removed of undermining them completely.
The Trust with all permissions in place set about removal. However, unsuccessful trials to cut it with a mechanical jack hammer proved fruitless and it was decided to use a large track machine with a hydraulic pecker.
Access was difficult and over land with knotweed prominent on both sides. After a visit by the contractor and agreement with all parties it was decided that a short steep route that would miss the knotweed was favourable.
Permission from the landowners was granted for the new route and the weir was successfully removed. The river had formed a deep hole on the downstream side of the weir and it was realised that to stabilise the river bed this had to be filled in. This was done by using the broken sections from the weir and some dry river shoal.
Typically when breaking up the weir we came across some amazing reinforcement material from metal bars to twisted wire and in the final section a whole car engine, waste not want not.
On completion the river was regraded the banks reinforced. Successive floods have done the final grading, and erosion of the banks, particularly towards the railway line has now stopped.
Whilst this weir was regarded as passable at all flows, the main benefits of the work are; improved channel diversity, river connectivity, reduced build up of debris, reduced bank erosion particularly towards the railway line. It has also scoured and cleaned the gravels downstream of the site improving conditions for spawning fish. No mean feat on a recovering industrial river.