More than 400 fish died when 3km of river was polluted with sewage and trade effluent, Chelmsford Magistrates’ Court heard on Tuesday . 

Services pleaded guilty to causing the pollution, which came from a combined sewer overflow in Thaxted, Essex. The company was fined £36,000 and ordered to pay full costs of £5,973. Mrs Claire Corfield, prosecuting for the Environment Agency, told the court the overflow ran into a stream which feeds into the River Chelmer and could have been avoided. “Anglian Water admitted that before the incident this stretch of sewer was not included on the schedule of planned preventative maintenance,” she said. A member of the public reported pollution and dead fish in the River Chelmer. 

Agency staff investigated and found sewage solids and rags discharging into the stream from an outlet in Park Street, Thaxted. There was a blockage in the foul sewer at the junction of Copthall Lane, Weaverhead Lane and Tanyard, the court heard. An Anglian Water operative cleared the blockage and told Agency staff they had cleared a blockage in the same stretch of sewer a week before.

A manager from the water company told investigating officers that the blockage had been caused by a third party blockage of debris comprising a metal handle, part of a bicycle brake, an old cover, various bits of lateral and private sewers. He said that since the blockage, the combined sewage overflow had been included on the list of preventative maintenance.

Mrs Corfield told the court that a total of 421 fish had been killed including lamprey, bullhead, minnow, stickleback and stone loach. She said lamprey had a limited distribution in East Anglia and in parts of the UK their numbers were declining – 52 dead lamprey were found. Bullheads are also highly protected because of their environmental vulnerability – 50 dead bullheads were recorded. After the hearing Environment Agency officer Silvia Moros Perez said: “This site was poorly managed and this pollution and these fish deaths could have been avoided if appropriate preventative measures had been in place for this section of sewer.” Anglian Water Services Ltd pleaded guilty to:

On or about 24 June 2011, you did cause the entry into inland freshwaters, namely a tributary of the River Chelmer, of poisonous noxious or polluting matter, namely sewage and trade effluent, at Park Street, Thaxted, Essex Contrary to Regulation 12(1)(b) and regulation 38(1)(a) of the Environmental Permitting (England and Wales) Regulations 2010