WATER TUNNELS in east London are reported to have been clogged up by an infestation of mussels clinging to the inside of the pipe work.
Contractors for Thames Water have already removed thousands of tonnes of the rapidly breeding zebra mussels from 3m diameter raw water transfer pipes at reservoirs around east London.
Site workers are manually scraping off the mussels, which have a distinctive black and white shell, because strong chemicals cannot be used in the water network.
Thames Water is reported to have acted after engineers noticed a drop in water flow in the pipes.
A spokeswoman for Thames Water rejected reports that an infestation of mussels could pose a threat to the capital's water supplies. She told GE the problem only affected the raw water transfer pipes which bring fl ow from the river into the reservoirs and poses no threat to water supplies.
The shells are believed to have entered the raw transfer pipes from the river, having got there on the bottom of ships.
'This is not an anything unusual and it affects quite a lot of water pipes around the UK, ' said the spokeswoman. 'It's something we do as routine and something we are completely on top of. It doesn't affect us in any way in terms of the water supply, ' she added.