What’s polluting the river Wandle?

By - Friday 17th March, 2017

Pollution is seriously affecting the flow of the river through Wandle Park

River Wandle, Friday 20th January 2017.
Photo by Amanda Kentfield, used with permission.

On Monday 24th February, early morning dog walkers saw an oil slick at the downstream end of the Wandle river, next to the skatepark in Wandle Park. Next day, although still present, it was much reduced and by Thursday 27th only a couple of small smears remained on the surface. Then on Friday 28th, a new and much larger slick appeared.

By Saturday, this slick was affecting the entire visible length of the river. There was a strong smell of petrol. Dippers were spotted diving into small gaps in the surface of the oil. By Sunday, it was once again reducing, but thin oil slicks were still visible where the end of the culvert discharges into the park and a lot of oil remained at the downstream end. The culvert was evidently the source of the problem.

Oil slick on the Wandle, Monday 24th February 2017.
Photo by Peter Ball used with permission.

I had first became aware of pollution in the park on Friday 20th January, when the Wandle’s water was discoloured by what appeared to be antifreeze. I now understand that similar problems had been observed by others prior to this. Since 20th January, pollution has recurred on an almost daily basis. As my concern about the issue increased, I began daily observation with photographs from 20th February.

So where does this culvert run? It presumably crosses under the railway and tramline, then under Waddon New Road, passes underneath the length of the footpath directly adjacent to the south side of the Wandle Arms pub, then crosses the end of Bourne Street. Bourne Street covers a tributary stream and ponds. The culvert then runs between the Salvation Army barracks and the back gardens of Rectory Grove, curves to run along underneath Roman Way and the Old Town dual carriageway, then follows Southbridge Road. Flood risk maps of the area show the source of the Wandle as being in the centre of Caterham (despite an urban legend that it rises beneath the Swan and Sugarloaf on Brighton Road). Pollution could therefore arise from any site along this route, via Victorian surface water drainage systems between Croydon flyover and Caterham.

The other main possibility is that more recent roads, including the roundabout underneath Croydon flyover, Roman Road and the Old Town dual carriageway, drain into the culvert. On a rainy day, oil slicks appear along busy roads: this is often light oil condensing out of exhausts, or caused by drivers with fuel leaks. The surface water drainage infrastructure in this area originates in the 1960s, a period when such drainage into the river would have probably been regarded as acceptable.

Image by Croydon Council, used with permission.

The pollution was reported to Croydon Council and to the Environmental Agency, which undertook an immediate investigation led by Kyle Cullen, Environment Officer from the South London Land and Water Team. Two EA teams attended the site to sample the water. The teams concluded that the water chemistry is ‘within the safe range’ and that ‘the most likely cause of pollution is run-off of oil and other liquids’. Kyle Cullen stated that ‘one of the main problems in this area is the level of commercial and residential activities impacting the site’.

The EA has now closed the incident since its finding was that the Wandle’s water chemistry had not breached safe levels. It states that visual inspections and water sampling will continue when officers are in the area. 

Despite the EA’s conclusions, I remain concerned. Although the two measurements taken were within safe limits, my observation is that visible levels of pollution fluctuate greatly from day to day. Without consistent daily measurement (which is expensive), it’s therefore possible to conclude that levels are within acceptable limits when in fact they are not. But in any case, I consider the current situation unacceptable.

Since 20th February, when I started walking the length of the river in Wandle Park every day, there has not been a single day on which I could not see at least some visible pollution. On 14th and 15th March there was a large amount of strange white and blue scum on the surface of the river, trapped by the lower bar of the gate at the end of the culvert – this will obviously flow into the park once the water level rises. As photographs show, the river’s appearance when these slicks are discharged into it is worrying.

Scum on the river in Wandle Park, Wednesday 14th March 2017.
Photo by Peter Ball, used with permission.

It is inevitable that wildlife will be affected by the pollution: think of the birds diving into gaps in the oil. A pair of dippers is nesting in the bank; these feed on invertebrates which live in the polluted water. Mallard ducks feed on water plants growing on the bed of the river and I have seen a pair of water voles nesting in the bank (although not recently, unfortunately). On 14th March there was an adult dead frog upsidedown on the middle of the river bed.

Park users are worried about the impact of pollution, as well being affected by the unpleasant smell and appearance of the river. Many in Croydon are proud of the work that was done to resurface the Wandle, and the way that this has enriched the lives of local people.

On Monday 12th March, two council notices were put up in the park asking users to be aware of pollution incidents, to report these to the EA and to be mindful of possible causes such as run-off from garages or pouring antifreeze or oil down drains. It is to be hoped that the source of the problem can quickly be identified and resolved.

Peter Ball with Liz Sheppard-Jones

Peter Ball with Liz Sheppard-Jones

Peter Ball moved to Croydon three years ago. He's a mathematician and former full-time communard hippie, architectural draftsman and planning technician for the Peak District National Park. Nowadays he's a partner in a translation company and a computer consultant. 'Quite conventional and boring sort of bloke', although his description of himself, is not the view of others. Liz Sheppard-Jones is a member of the Citizen's editorial team whose views are personal, not reflective of editorial policy.

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  • Rosie E

    Really glad you’re raising the profile of the Wandle’s health (and we’ve always wondered where exacty it flows before arriving at the culvert.)

    A few years ago there was a massive drive to clean it up from here to Beddington Park before fish were released into it..I think it was featured on Blue Peter and we waded along stretches of it in celebration… memory unfortunately hazy on the details of which organisation masterminded it though…

  • blath8@googlemail.com

    Interesting …….. I wonder if the Environment Agency person testing the water would have been happy allow their child or pet to wade in the river …..

    Thanks for highlighting this – is there a way to carry out independent tests on the water quality?

  • Isabelle

    I been walking alongside the Wandle recently and looking to collect some of the berries and fruits that grow along the hedgerows, and I’m worried about picking these for eating and preserving if there has been a long history of contamination in the river Wandle. It is still quite industrialised with commercial properties surrounding but not the kind of industry that directly pollutes the river. It sounds likes from the article that the water pollution is within the safe limit but I’m not sure how much this can affect the fruits. Would anyone be able to advise? Thanks