In late October last year the River Crane and the Duke of Northumberland’s River were both devastated by the uncontrolled discharge of an enormous volume of raw sewage. The incident occurred due to the blockage of a large Thames Water sewer main and the subsequent release of effluent into the river rather than allowing it to flood Heathrow Airport.
Over the last year the Friends of the River Crane Environment (FORCE) have been reviewing what has happened in response to this disaster and how the river is coping. We know that, immediately following the pollution event, the river was essentially dead, all the fish and river insect life being killed along the 20 kilometres of the River Crane and Duke of Northumberland’s River between the outfall (next to the A4 in Cranford) and the River Thames.
Around 7,000 mature fish, including seventeen different species, were bagged up and sent to Mogden to be counted and we estimate that upwards of 10,000 fish were killed in total.
Over the last year we have witnessed a slow recovery of the river. FORCE undertook its first regular river sampling in March and found that no fish, and only a few river insects, had returned. Over the last few months we have seen that the numbers and variety of insect life have largely returned to the river. Fish numbers are also slowly recovering naturally.
At the end of last year the Environment Agency drafted a strategy for restocking the lower Crane with fish farmed at their facility in Calverton. The strategy aims to introduce several species over a 4 year period. The first batch of 5500 fish were released into the river in December 2012, they included 1,500 Chub, 1,500 Dace, 1,500 Roach and 1,000 Barbel, all paid for by Thames Water. The fish selected were young and were species that were present in the river prior to the pollution event. Further fish releases are planned following a period of monitoring.
FORCE have been working with the Environment Agency and other members of the Crane Valley Partnership on plans to restore and improve the river Crane. We had been hoping to encourage a more natural recover of the river but we understand that this would have taken longer to achieve, somewhere between 10 to 15 years.
FORCE would like to see a restocking strategy that reflects the species of fish that were present in the river prior to the pollution incident. We are hopeful that the Environment Agency have undertaken to re-stock the river with a wide variety of fish and that the scheme will be supplemented by fish passes installed on the river that will allow a natural recruitment of fish from the Thames and upstream. This is important as it is not possible to include fish such as eels and bullheads in the restocking scheme.
FORCE also looks forward to the imminent recruitment of an officer to develop and implement a plan of action for the restoration of the river over the next five years, with the bulk of the funding being available for river improvement projects. This post is being funded though a formal commitment from Thames Water to work with the Crane Valley Partnership.