Tag Archives: Pollution

Wandle cleanup: December 2014: Wandsworth

This December we returned to Trewint Street in Earlsfield. It was a cold cleanup, but 20 dedicated volunteers powered through to remove a serious amount of rubbish from the River Wandle.

This month’s cleanup was funded through the Living Wandle Landscape Partnership as part of our River Guardians project. Before we got started, I gave everyone a brief update on our current work tackling pollution along the Wandle. The Wandle Trust has been busy trialling several new methods for pollution mitigation including Siltex and mycofiltration.

After this and the Health & Safety Briefing, it was time to get stuck in.

The first item on our cleaning agenda was a motorbike upstream of our cleanup site. Chris volunteered to head a team of 6 volunteers to pull this from the river. Luckily, the bike was a recent dump and hadn’t had the chance to sink into the sediment yet.


With brute force and a couple of grapples, the bike was soon pulled onto the bank – and we couldn’t resist having a little ride.

Going for a ride

With the bike removed, the team headed back downstream to tackle some other big items which had been spotted.

The first of these was a whole armchair, wedged under the Trewint Street bridge. With grapples, the chair was dragged to the concrete banks and up the side. But not before our workers had a little rest.

The Armchair

It wasn’t our wading team getting all the glory at this cleanup, there were some serious hotspots for fly-tipping at our site. Our litter pickers shifted wooden pallets, fencing and several other large pieces of rubbish, clearing the island at Trewint Street bridge.

Fly Tipping

After all this hard work we were ready for our tea break. As it was so close to Christmas, we had mince pies and ginger cake this month, kindly supplied by Sally and Jana.


Following lunch, it was time to move on to the washing machines further downstream. Pulling these up a vertical concrete bank was not an easy task but our volunteers managed the impossible. Using carefully placed grapples, both washing machines were retrieved from the river fully intact!

Washing Machines

Terry from Wandsworth Borough Council showed up to collect the rubbish in the afternoon, by which time our pile was already worryingly large. In fact, we were told to stop shortly after lunch as we had already filled up the rubbish lorry!

The Rubbish Pile

So what did we find? 1 stove, 1 motorbike, 1 garden fence, 1 Thomas the tank engine toy, 1 hanging basket, 1 computer, 1 tyre, 2 suitcases, 2 washing machines, 7 bikes, rolls of carpet, 60 bags of rubbish and endless fencing panels.

Huge thanks to Mark who met me early to load and unload the van; Sally and Jana for catering for our 20 volunteers; Theo and John for helping supervise everyone on the day; to the Waste Management Team at Wandsworth Council for organising collection of all the rubbish on the day.

Thank you to all our volunteers for coming: Aaron, Alice, Carol, Charles, Chris, David, Derek, Diana, Gerald, John L, John N, Mark, Michael, Mike, Penny, Polly, Rose, Sally A, Sally P and Theo.

So what did I learn from this month’s cleanup? No matter how steep the bank, hauling a washing machine up a vertical concrete cliff is always possible.

The Siltex is in!

Have you walked past Carshalton Ponds today? If you have, you may think it is looking a little different…

The White Carshalton Ponds

The ponds have turned a milky-white colour. But do not fear, this was intentional! Working with the Environment Agency, we have just added two tonnes of Siltex to the ponds.

Siltex is a natural chalk-like substance which helps to increase the speed of silt breakdown by stimulating natural processes. (Click here to read more about why we are doing this).

We had eight dedicated and brave volunteers join us at 8am on chilly Tuesday morning. Everyone was kitted out with waders, goggles and masks – Siltex isn’t dangerous but we wanted to be extra careful.

Siltex Volunteers

Steve stepped up as Captain Siltex to join Olly in the boat, throwing Siltex overboard in the deeper waters. For the morning, our vessel was kindly lent to us by Sutton Council. In the afternoon, Olly and Steve commandeered a smaller boat from the Sutton Ecology Centre. Without these boats, we wouldn’t have been able to apply the Siltex at all so we are extremely grateful to Dave Warburton, Ian Hudson, Warren Chapman, Collin Franklin and Mark Featherstone for loaning and delivering these boats on the day.

Captain Siltex

While Steve and Olly sailed the open seas, the rest of us were adding Siltex from the shore, showing off our throwing skills. This allowed us to get a good coverage over the shallower parts the boats could not access.

Adding Siltex by hand

Throughout the day, the Environment Agency were taking readings further downstream to ensure everything was working as it should.

Olly will be monitoring this regularly for the next few months to determine if it is a cost effective solution to the management of silt at Carshalton Ponds. Last week, Olly and I took some pre-Siltex water samples on a chilly and damp morning.

The Water Samples

Why are there four different bottles I hear you ask?

The reason for this is that there are several different substances which are of interest in the ponds. We are interested in what effect the Siltex might have in speeding up the breakdown of several contaminants (e.g. car exhaust particles) as well as reducing the overall volume of mud. Different tests are required for different substances – for instance hydrocarbons (oils and fuels) stick to plastic, so must be stored in a glass bottle if they are to be extracted and analysed. So different bottles are needed for each different test!

While we were out we rescued Woody from the Wandle – he is now our unofficial Mascot for the project! He even joined us for the Siltex event, although came out a little worse for wear….

Woody Before and After

Keep your eyes peeled for more updates!

The Problem with Urban Duck Ponds

In a highly developed landscape such as Greater London, urban ponds can provide an important haven for wildlife and therefore it is important to keep the waters happy and healthy.

Carshalton Ponds

Unfortunately over time urban ponds tend to fill up with sediment washed from the surrounding area such as leaf litter and bird droppings. Have you ever been for a walk along the Wandle to Carshalton? If you have, you will have undoubtedly seen a mass gathering of wildfowl at the ponds. These high densities of geese and ducks can be a particular problem with their droppings increasing the organic content of the ponds, resulting in algae blooms and a deterioration in the water quality.

The Birds!

So what can we do?

The Wandle Trust are trialling Siltex in Carshalton Ponds as a potential solution to the surplus of silt.

Siltex is a natural chalk-like substance which helps to increase the speed of silt breakdown by stimulating natural processes. It is environmentally friendly and is harmless to plants and animals.


In the next week, we will be applying the Siltex powder to the mud in Carshalton Ponds. The effects of Siltex will then be monitored closely over the next few months by our staff to determine the effectiveness of the measure and its effects on water quality.

We will of course keep you updated with our news – so keep your eyes out for more Siltex blogs.

Pollution-Busting on the Wandle

Over the last 2 years, the Wandle Trust has been intensifying efforts to tackle the considerable problem of pollution in the river. Often contamination can be tackled by our partners in the Environment Agency, tracking down pollution to the source. However, this does not work for all sources of contamination.

For example, contaminants such as particles from car exhaust, the loss of engine oil and other contaminants from the roads can all be washed into the river from no one “point” source. This is known as diffuse pollution.

To illustrate this, there are about 2.5 million cars in London, and 16% of them leak oil. It has been calculated that this would equate to 261,635 gallons of oils dripping onto roads every year! Much of this oil will work its way into London’s surface water drains and then the rivers.


Although changes to the law and car technology may help one day in the future, we need to start acting now. It has been the Wandle Trust’s mission to find out how the contaminated waters from the surface water drains can be cleaned up before entering our river. This is vitally important because water quality is a major determinant of what wildlife can live in the rivers, how beautiful the rivers are, and how much the community value their local water landscapes.

In the current phase of our Pollution Busting Project, four measures are being installed and trialled to determine their effectiveness in reducing the contamination coming into the River Wandle. These measures are the most promising selected from several which were investigated by the Trust and they are called:

  • Downstream Defenders
  • Mycofilters
  • Siltex
  • Smart Sponges

There will be more information about these appearing on our websites in the coming months. We look forward to telling you more about this exciting new phase of our work!

Pollution Monitoring on the Wandle: Two Years Later

It’s hard to believe that it has been almost two years since the Wandle Trust teamed up with the Environment Agency to clean up pollution on the River Wandle.

Our Pollution Monitoring Scheme has trained 50 local volunteers to attend and assess Category Three pollution incidents and report back valuable information to us and the Environment Agency.

Another great element to this scheme was regularly monitoring specific outfalls along the Wandle that have been a problem in the past. Volunteers adopted an outfall close to them and checked the site once a week for signs of pollution. This information was fed back to the Environment Agency allowing them to prioritise and investigate key issues.

The pilot scheme has been a huge success demonstrating the value of volunteers in monitoring pollution in an urban environment. Its innovative and collaborative approach earned the scheme the Rivers Trust Award for Science and Innovation in 2013 – a huge achievement for all those involved!

To celebrate this award and the success of the scheme, we invited our dedicated volunteers to Strawberry Lodge in Carshalton for some evening tea, coffee and cake.

Our Volunteers and their Award

The Environment Agency are very grateful to all the volunteers involved and have put together a short piece to summarise what was achieved thanks to their hard work. Click this link to download: Environment-Agency.pdf (138kb).

The scheme is also being rolled out on the Hogsmill and Beverley Brook. If you’re interested in becoming involved, please email us at volunteering@southeastriverstrust.org.


Trout in the Classroom 2014: A fond farewell

At the end of April, on a bright spring day, the Trout in the Classroom graduates of 2014 finally got the sending off they deserved. Five south London schools along with the Deputy Mayor of Merton (Councillor John Sargeant) and Wandle Trust staff and volunteers were there to mark the event.

The Deputy Mayor began proceedings with a perspective on just how far the river has come since he was a boy growing up in the area. He then gamely obliged us by stepping into a pair of waders and lowering himself into the river to help the children with the release.

Deputy Mayor talking at release 2014

There was no shortage of excitement on display. For the children, the day was the culmination of a fascinating journey of discovery into the life a native fish species – from egg to alevin to fry – literally opening up a whole new world.

Kenley fish at release 2014

As an adult watching the event, it strikes you how tangible the exhilaration of the children is – something that is perhaps no longer that familiar to us. It extended to secondary level – if in a more controlled fashion! – as students from Francis Barber PRU and Sutton Grammar also were clearly pleased to be in the river and part of the event.

Mayor with Kenley students at 2014 release

I was particularly interested in the reaction of students from Culvers House primary school, some of whom spent their time enthusiastically picking up litter and pointing out rubbish on the river bed. Although wishing to oblige them, by the time those in the water got around to looking for the rubbish, too much silt had been kicked up for it to be seen, to the disappointment of the children.

Kenley Release 2014

Their enthusiasm nonetheless impressed me, and it struck me how much their optimism and belief in their ability to make a difference is such a precious commodity that young people are uniquely gifted with, and is something that we should be doing our very best to protect and cultivate. It is a crucial part of changing things for the better. And with its story of successfully reintroducing a breeding population of brown trout into a once heavily polluted and industrial environment, Trout in the Classroom once again demonstrated how it can play such an important role in keeping that optimism alive.

Note: River pollution and Trout in the Classroom

Anyone familiar with TitC will notice that the release was a little later than usual. Normally timed to occur before the Easter holidays, the release day this year had to be postponed by a month on account of a significant pollution spill in the river.

Following the heavy rains over the winter, large amounts of water entered the works as a consequence of the high water table and mixed with the untreated sewage. This overwhelmed the treatment plant storage capacity and Thames Water were obliged to discharge the raw sewage directly into the River Wandle. Although no fish kills were reported, oxygen levels were severely depleted.

Even since the release, further pollution incidents have occurred. The connection to Trout in the Classroom is appropriate as it serves as a reminder how the Wandle is still a river with an uncertain future facing significant man-made threats. This is why education projects like TitC have a vital role in helping local people feel invested in the health of the river and the species that depend upon it, and can teach them to be alert to any deterioration in its condition. In turn, this could help build the consensus for the authorities and water companies to make the investments required to eliminate these threats.

(All photos: (c) Mike van der Vord)

New pollution issue: Monday 12 May 2014

We have had reports from Thames Water and the Environment Agency of a new issue on the Wandle (possibly a different one from Friday’s issue). There is pollution entering the river from the sewage effluent channel at Watermeads Lane which has potential to become a serious issue for the river. There are a number of channels and outfalls that feed into the effluent channel (not just the sewage treatment works) and the source and identity of the pollutant is unknown at present. The EA and Thames Water are currently investigating.

Please can you keep your eyes and noses on the river.

If you see any signs of pollution (rags, solids, smell, suspended solids, murky water and especially fish or wildlfe in distress) please call the EA on 0800 807060.  

Any observations anywhere downstream of the effluent channel confluence (photo and a note of what you can see/smell) would be appreciated to pollution@wandletrust.org or call on 07771770418

Pollution update: Friday 9 May 2014

You may have noticed that the river below the effluent channel input at Watermeads Lane is very murky brown recently.  Polluted water is entering the river from the effluent channel and is colouring the water as far downstream as Morden Hall and beyond.

eff channel silt

Confluence of the effluent channel and the Wandle showing heavy suspended solid pollutant entering the river.

Kate Mc Dermott from the EA is investigating the issue at the moment.  Investigations as to where the source is located are ongoing.

The Environment Agency team are out on the river today conducting a biological assessment to see what impact the pollutant that is depositing is having on the flora and fauna in the river.  There have been no reports of fish in distress thankfully but invertebrates are likely to be at risk.

eff channel bug count

Invertebrate monitoring on site today – this will tell us what the impact is on the river health.

We will update this site once we know more.

Mycofiltration: using mushrooms to clean the river!

Mycofiltration is the pioneering technique of using fungi to filter out pollutants from water.  First developed in the USA by Paul Stamets, we are trialling it here along the River Wandle for the first time in the UK!  We have put several ‘mycofilters’ around surface water outfalls that drain into the river to capture pollutants such as heavy metals, hydrocarbons, bacteria and excess nutrients and will be monitoring their effectiveness over the coming year.

A mycofilter is basically a hessian sack filled with wet straw and wood chip and mycelium (the non-fruiting part of fungi).  They look a bit like slightly mouldy sandbags, but don’t let that put you off!!  They are doing important work.

Getting to the point of being able to install mycofilters along carefully selected study sites by the Wandle took several stages…here’s what we did in a quick run-through:

Stage 1: preparing materials


40 kg of mushroom spawn was ordered from a specialist UK supplier and carefully weighed out to the correct portions needed per hessian sack.4 m


Several locally sourced straw bales were acquired from Bushells Farm in Carshalton.


Freshly chipped wood sourced from native deciduous trees cut by Sutton Council was collected from Central Nursery Wood Station in Croydon.

 Stage 2: building

Then the first of three workdays was held at Sutton Ecology Centre to make the mycofilters themselves.








All the materials needed: straw, wood chip, hessian sacks, mycelium spawn and a plentiful supply of fresh water were laid out as an attractive buffet (!) for volunteers to build


Volunteers worked in pairs – one to hold the bag open and the other to scoop in the materials.


The ingredients were layered like a special lasagne: first a good layer of wet straw…


Then a scoop or two of wood chip…


Then a generous sprinkling of mycelium was added and the layering process repeated, until the bags were tightly packed and full.


The finished sacks were put into rubble bags to protect them and volunteers took a bag or two each home with them to develop in their gardens over the next few weeks.


After five weeks typically, the mycelium had grown throughout the sacks and was visible on the outside as a white feathery network of filaments – they were ready to install!

Stage 3: installation

Three more workdays were held to invite the volunteers back with their sacks and to install them at the study sites by the river.


The first site tackled was Bennetts Hole Local Nature Reserve in Mitcham, where pollution was entering the site via pipes from a neighbouring Industrial Estate feed to a reedbed.


Despite a hailstorm during proceedings, no one’s ardour was dampened and three sets of installation were completed successfully.


Thanks to everyone who braved the inclement weather!


Despite the weather, there was no let up and installations were then carried out at the Mill Race in Grove Park


at Wandle Bank


Butter Hill


and Beddington Park!

The mycofilters will now be monitored regularly, with water and silt samples sent away for analysis.  Watch this space for further updates!

 If you notice the mycofilters have been disturbed or removed at any site, please let us know. 

 Thanks to everyone who has worked so hard to help Claire with this project; it has been great fun and you can feel proud of the fact that you are all conservation pioneers!

Photos by Claire Bedford, Mark McLellan, Bella Davies and Erica Evans.

Pollution alert: Storm flows from Caterham Bourne through Beddington sewage treatment works

Following our recent report that record rainfall this winter has resulted in the reappearance of the Caterham Bourne, we’ve just received this information from the Environment Agency:

Because of the high ground water from the Caterham Bourne, ground water is being pumped into the foul sewer to relieve flooding issues in the Kenley and Purley area.  This is also to protect Sutton and East Surrey’s potable water treatment works at Kenley.

Because of this there has been an increase in water flowing into Beddington Sewage Treatment Works and the Works are running under storm conditions. This means that the water coming from the works is a mixture of final treated sewage and storm water.
This has been going on for a few days now and could last for a while. However, several partner organisations including the EA, Thames Water, local Councils, the Police and Fire Brigade are working to manage the situation as immediately and effectively as possible.

Needless to say, we are taking this situation very seriously, and will post updates here as we receive them.

Update 1 (2.30pm, Monday 24th Feb): the EA have informed us that “free ammonia” NH3 levels are currently very low in the lower river, and no environmental damage has been detected so far.  However, sludge which has been scoured from Beddington’s storm tanks may be getting into the river, and may look like shredded toilet paper or similar.

Update 2 (12pm, Tuesday 25th Feb): There is sewage debris, sludge and fungus being seen all along the river downstream of the effluent channel to at least Penwith Road.  Water is not being pumped to the foul sewer now but the amount of water entering the sewage treatment works is still high and is therefore still operating  under storm conditions.   Dissolved oxygen levels are low but not thought to be a cause for concern yet.

If you’re out on the river and notice offensive smells, unusual quantities of sanitary products, or fish or other wildlife in distress below Beddington STW, please phone them in to the usual EA hotline: 0800 80 70 60. Thank you!