On Tuesday 24 June 2014, Severn Trent Water pleaded guilty at Nottingham Magistrates’ Court to one charge of pollution in Nottinghamshire. They were fined £10,000, ordered to pay £2,659.63 in costs, along with a £15 victim surcharge.

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The charge was brought by the Environment Agency contrary to Regulation 38(2) and 12(b) of the Environmental Permitting (England and Wales) Regulation 2010. On 12 March 2012, Environment Agency officers attended an incident on the Potwell Dyke watercourse in Southwell, Nottinghamshire. The incident was reported by Severn Trent Water who said that water pollution had discharged into the watercourse from their combined sewer outfall. Under the terms of their environmental permit consent, Severn Trent Water were permitted to discharge into the Potwell Dyke but only during storm conditions, when flows in the overflow exceed 15 litres per second. This is to protect the downstream properties from the risk of flooding during a storm. At the time of the pollution report weather conditions were dry.

On attendance officers went to the footpath just off Halloughton Road, where it was possible to see the outfall to the Potwell Dyke from Severn Trent Water’s combined sewer overflow. There was no flow from the outfall at that time, but officers observed debris around the outfall and solids on the bed of the watercourse. The water flowing down the Potwell Dyke from upstream of the outfall showed no visible signs of pollution. When officers looked at Potwell Dyke from the footbridge, downstream of Halloughton Road, the water appeared cloudy. The officers also saw dead fish in the watercourse immediately around the bridge. Both officers continued further downstream to establish how much of the watercourse had been impacted by the pollution. Tests carried out showed that ammonia levels were elevated in places as far as 2km downstream.

On 15 March, Environment Agency officers returned to Southwell and met a representative from Severn Trent Water where they had contractors on site working to remediate the pollution and remove debris from the watercourse. The Potwell Dyke was grey/brown and still appeared cloudy at the sewer outfall. In places a pale scum was visible on the surface of the water. The following day an officer returned to the Potwell Dyke. Severn Trent Water’s contractors were still on site and had placed sandbags in the watercourse to prevent excess solids being carried downstream during the clean up from the culvert.

The watercourse appeared much clearer downstream of the sandbags than upstream.

Speaking after the case, an Environment Agency officer in charge of the investigation said: Although Severn Trent Water reported the discharge to us immediately, it was too late to prevent the pollution of the Potwell Dyke. We do everything we can to protect the environment, local rivers and watercourses. This case sends out a clear message that we will not hesitate to prosecute as necessary when environmental damage is caused. In mitigation, the court took in to account Severn Trent Water’s early guilty plea and said that culpability was low because of their inspection regime and no previous incidents at this location. Severn Trent Water’s response to the incident was adequate; there was remedial action taken and a minimal impact on the ecosystem.