Source: Environment Agency
We would like to update you on the recent pollution incident on the River Crane. We were made aware of reports of two incidents in the Twickenham area of the morning of Thursday 3 October 2013. These appeared to be associated with heavy rainfall. We were then alerted that afternoon by the monitoring station on the River Crane of low dissolved oxygen and high ammonium levels.
An immediate investigation began, with an Environment Officer deployed to site that afternoon and multiple officers on site the next day from first light. Working with Thames Water we began to trace the course of the pollution through the surface water sewers. As a precautionary measure Thames Water ceased pumping sewage sludge through their foul main, which is located in the area. The discharge from the outfall stopped on Friday afternoon and we began to see improvements in the water quality.
Investigations showed that a Thames Water main carrying treated sewage sludge between their treatment works at Mogden and Iver was fractured by an unknown third party. It was sewage sludge from this damaged pipe that caused the pollution. The damage to the sludge pipe was repaired by Thames Water on Saturday morning 5 October. The Environment Agency is now carrying out a criminal investigation into identifying those responsible.
We are asking for the public’s help for information relating to this incident. You can find full details of our appeal at the end of this update.
We have been assessing the full impact of the pollution incident which affected the River Crane. Our water quality monitoring stations have revealed water quality downstream of the site of pollution recovered to the levels found before the incident in a matter of days. Environment Officers have also been walking the riverbanks, to visually assess any significant deposits of sewage sludge along the watercourse and any other physical impact to the environment. Whilst along much of the length of the River Crane the water clarity has improved, there are some stretches, particularly where the river is more slow flowing, where the water remains turbid and deposits of sewage sludge have been identified. We have been conducting upstream and downstream fishery and invertebrate surveys, to give a clearer picture on the impact to river life.
Although a significant number of fish and invertebrates died, we have seen evidence that some have survived; fisheries surveys are still ongoing.
Appeal for information
Between Thursday 26 September and Thursday 3 October 2013 we believe a low loader lorry delivered a 360 tracked excavator to open land at the Parkway (A312) junction with High Street, Cranford, TW5. The excavator was picked up by another low loader lorry – possibly the same one – on Wednesday 2 or Thursday 3 October. While the excavator was on site, tipper lorries entered and deposited soils and other material which was pushed up and shaped into a low embankment around the site by the excavator. We believe that this activity happened during the day, into the evening and throughout the weekend.
The weight of the vehicles, and possibly excavations carried out, appear to have fractured a sewage sludge main that runs beneath the site and the sludge escaped via the surface water drains to the river causing the pollution. We are appealing for information that will help us identify any of the lorries or machinery used. This includes for instance make, model or registration numbers, company names, livery or hire company names to assist our investigation. The site entrance is next to a 24 hour bus stop and The Queens Head pub. The operating area is visible from Cranford High Street and the A312 Parkway.
Both the waste and water pollution offences carried out were criminal offences.
You can report any information through the incident hot line on 0800 80 70 60 or through Crimestoppers on 0800 555 111, or online HERE
