Reg. Charity No. 1091000

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It’s a Midge Issue!

Last Friday morning Luke and I went to Ravensbury Park to meet MP Siobhain McDonagh as well as Area and Environment Managers from the Environment Agency, London Borough of Merton Councillors and over 20 local residents. Local residents have been suffering from clouds of midges emerging from the river through the Park and have understandably had enough! So we all met to discuss what could be done about it.

Chironomus plumosus MHNT

An adult midge (“Chironomus plumosus MHNT” by Didier Descouens – Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons – http://commons.wikimedia.org/wiki/File:Chironomus_plumosus_MHNT.jpg#mediaviewer/File:Chironomus_plumosus_MHNT.jpg)

The midges are chironomids which spend the first part of their lives in the river itself. They then pupate and emerge as flying adults, surviving for only a few days to mate and lay eggs at the river’s surface. The problem is that there are so many midges emerging in Ravensbury Park that local residents can’t even open their windows, and it makes a walk through the Park quite unpleasant (and a cycle though the park pretty much impossible without swallowing a few along the way!)

These clouds of midges are an indication that the river ecosystem is out of kilter: the conditions are such that the midge population is not being kept in check as it naturally should, so it has boomed in the last 5 years (notably since the pollution incident in 2007 according to local residents).

Midges are ubiquitous creatures which inhabit most freshwater environments, but they particularly like still or slow moving water. During our meeting we observed that there are likely to be a number of contributory factors to the booming midge population, which all combine in a ‘perfect storm’ in Ravensbury Park (and possibly in Morden Hall Park too):

  • The slow sluggish nature of the water caused by weirs which impound the river, slowing flow and causing silt to drop out. Midge larvae thrive in these silty low-oxygen environments where other river life finds it hard to survive.
  • Ironically the Park’s many beautiful trees are likely to add to the problem, because the midges eat leaves which fall in and line the riverbed, breaking down to create more of these silty low-oxygen conditions. This is a reason why tree management around rivers is important (as well as allowing more light to reach the riverbed so that a diversity of plants can survive).
  • Another factor is likely to be a decline of predators such as other aquatic invertebrates (including damselflies which local residents said used to be much more abundant in the park) as well as fish, birds and bats. It’s possible that the many pollution incidents that the Wandle has suffered has contributed to the decline in fish, and the fish also tend to get washed downstream in high flows and can’t return upstream due to the number of weirs.
  • Finally, the water quality of the Wandle is very nutrient rich, as much of the flow is sustained from the effluent from Beddington Sewage Treatment Works. Beddington is operating within its licensed limits but the water quality downstream changes and this may contribute towards conditions that favour midge larvae in the Ravensbury Park area.

So what can we do about it? Well, the problem needs to be tackled holistically, addressing all of the issues – and we all have a role to play in this.

Currently, Luke is working in Ravensbury Park to help improve flow and habitat in the Back Channel. This involves thinning out some trees to increase light reaching the river, creating a low-flow channel to enhance the river’s resilience to drought conditions, enhancing the diversity of river habitats and increasing the velocity and turbulence of the water (making it more like a river and less like a pond).  Later this year, the Living Wandle Landscape Partnership Scheme is also planning to start similar work on the main channel through the Park.

All these improvements will help to reduce the conditions in which the aquatic midge larvae thrive in and restore the habitat for animals which would predate on them.

By continuing such river restoration – re-naturalising the Wandle and making it resilient to pressures like climate change – we will chip away at the problem, reducing the number of midges and hopefully encouraging many more attractive species to return to the Park.

January 29, 2015   No Comments

Going Round the Bend: Next Stop a Re-naturalised River

By Lawrence Hemmings, our River Restoration Volunteer

After a great deal of planning by Luke the habitat improvement works on the Ravensbury Park Back Channel have begun with the help of our contractors – Ru and Jack of AquaMaintain. The digger and dumper have arrived as have the hazel faggot bundles posts, not forgetting the loathsome pile driver (a 20 kg hammering tool essential for river habitat work). And without further ado splash!  Work could commence.

In order to create a more biodiverse, naturally functioning river, complete with runs, glides, pools and riffles, the Ravensbury Channel needs a little encouragement.  By securing the faggot bundles in an irregular zig-zag on both sides of the river, the variation in flow will scour out deeper pools, form riffles, and, with any luck, some gravels will appear – perfect spawning grounds for amorous fish!

The Back Channel

So Luke, Jack and I splashed into the river with our trusty pile driver at the ready. We pinioned hazel faggot bundles in place by hammering in stakes on both sides, and a new bank line quickly started to appear.

Meanwhile our adept digger driver Ru set about clearing the brush from the park-side bank of the river where we have removed the toeboarding, sheet piling and other bank reinforcements. In no time at all Ru had begun re-grading the steep-sided river banks, which will allow us to connect the river to its natural soil bank. The bank can then be planted with typical marginal plants, such as sedges and reeds, creating a continuum from aquatic to terrestrial habitat. We will also be digging a small back water, where the slack flows will allow fish fry to seek refuge away from the perils of the fast lane – the new turbulent Back Channel.

The Back Channel

Stay tuned for more updates!

January 29, 2015   No Comments

Wandle cleanup: January 2014: Merton

The one with the grabber lorry

With Sunday 11th bring the second Sunday of January – it was time for the first Wandle Trust cleanup of 2015.  Last year, we pulled out 8.5 tonnes of rubbish from the River Wandle – and we are keen to break this record in the next 12 months.

We started 2015 in Merton on North Road and as usual we got started after a Health & Safety briefing. We had 38 volunteers with us on a sunny but chilly Sunday morning – as well as our faithful supervising dog, Basher.

Basher

We split into two teams – waders and litter pickers. Our wading team hopped in the river and worked upstream finding all sorts of rubbish. It didn’t take long before they scouted out some “challenges” including a buried water tank which took grapples and some serious muscles to heave out of the river.

Water Tank

Soon our litter pickers returned having scouted out the park and surrounding area. They had discovered 3 trolleys further upstream and a giant piece of plastic roofing wedged by a tree downstream; both of which our wading team just couldn’t resist!

The trolleys were relatively simple – muscles and grapples – with all three trolleys in relatively good nick so we could push them (or hitch a ride in them) back to the rubbish pile.

Trollied

The plastic roof sheeting was another story. Roughly 3 metres wide and 5 metres long, the sheet was awkward and heavy to pull out of the river and disentangle from the undergrowth on the banks. However once free, all it took was a couple of huskies to pull the sheet back up the hill to the rubbish pile. Woof woof!

Plastic Roof

Huskies!

After hauling this sheet up the hill, we decided everyone deserved a break so we all gathered back at the tent for cheese scones and hot tomato soup kindly supplied by Sally and Jana.

But I wouldn’t let everyone rest for long as we had plenty of rubbish to remove! The afternoon saw the usual collection of Wandle objects:

Many many bicycles – including one which was so new, we rode it back to the pile!

Bicycle

Scooters galore!

Scooters

A golf club

A car door – my new ride…

My new ride

and a toy dinosaur – I always have to find a toy.

Dinosaur

At half two, Stan from Merton Borough Council appeared with the grabber lorry to collect the rubbish causing a stir of excitement back at base.  We got to see the grabber in action as it crushed our metal water tank as if it were made of paper.

Crushing Power!

So what did we find? 1 wheelchair, 1 leaf blower, 1 giant plastic roof sheet, 1 plastic dinosaur, 1 vacuum cleaner, 1 water tank, 1 car door, 1 frying pan, 1 bucket, 1 petrol tank, 1 orange, 1 lemon, 1 pineapple, , 1 half coconut shell, 2 traffic cones, 2 barrels, 4 tyres, 7 scooters, 7 bicycles, lots of carpets, miscellaneous piping, bags and bags of other junk.

Huge thanks to Gideon and Michael who met me early to load and unload the van; Sally and Jana for catering for our 38 volunteers; Theo and John for helping supervise everyone on the day; to the Waste Management Team at Merton Council for organising collection of all the rubbish on the day.

Thank you to all our volunteers for coming: AJ, Bella, Bertie, Charles, Chris E, Chris L, Claire, Dave, David, Derek, Elliot, Felix, Gerald, Gideon, Guy, Harry, Jamie, Jana, Jane, Jason, John, Keith, Mark, Matylda, Michael F, Michael H, Ollie, Penny, Richard, Sally, Stewart, Theo, Tim, Toby and Wally.

So what did I learn from this month’s cleanup?  That even if it looks like there is little rubbish in the river, the Wandle volunteers will somehow find enough to fill a lorry!

January 19, 2015   No Comments

Fungi versus Diffuse Pollution

Our Water Quality Officer, Olly, has been having a busy few months working to tackle urban diffuse pollution on the River Wandle.

If you missed the introduction to his work – have a quick read now!

This week, Olly, myself and some lucky volunteers will be installing the next pollution mitigation measure: Mycofilters.

Mycofilters (Mycos for short) are mesh sacks packed full of straw, wood chip and mycelia (the non-fruiting part of fungi). Over time the mushroom mycelia grow throughout the sack and create an expert filtration device. Once placed in the river, the mycelia filter out contaminants from the water which passes through them.

Mycos!

The Wandle Trust has already trialled growing and installing these filters. In November 2014, we held another successful volunteer day to make a further 60 bags with a slightly modified and more robust design.

This week we will be taking these fully grown Mycos and installing them on sites where pipes are potentially polluting the river. The Mycos will be installed securely to ensure there is no flood risk and will be monitored carefully over the next two months to determine their effectiveness.

So if you spot something odd looking close to the river – it is probably a Myco! Please don’t remove them and if you see one in jeopardy – let us know!

A BIG thank you to our Myco-making volunteers from November. Thanks to you we managed to make 6 Mycos in less than four hours! I’d also like to thank our sewing team who took the time to sew up 60 bags for us to stuff full of pollution busting goodness.

Our Myco Makers!

 

January 14, 2015   No Comments

Have you made your New Year’s Resolutions yet?

Have you made your New Year’s Resolutions yet?

I am sure many of you have started to think about what New Year’s resolutions you might make for 2015. If you’re like me, I usually go for “exercising more”, which means joining the gym and then proceed to never use my membership…

But help is at hand. The Wandle Trust has some suggestions for your resolutions this year, and they’re a bit different because they’re all about your local river!

Resolution One: Report Pollution!

If you spot a pollution incident on the Wandle or any other river, report it to the Environment Agency on 0800 80 70 60. You are the eyes and ears for your local stream so don’t hesitate to report anything you think is unusual!

Connect your House right

Resolution Two: Connect Right

Some pollution is caused by bad plumbing. Houses may have been connected to the wrong drainage system, sending waste directly into the nearest river. You can check that your house is connected right at www.connectright.org.uk

Resolution Three: Clean with Care

Phosphates are a big problem in both urban and rural rivers. A high phosphate level reduces water quality and increases the growth of algae blooms. Eco-friendly detergents are specially manufactured to have a minimal phosphate content, so you can use these to protect your river and its wildlife.

Wash with Care!

Resolution Four: Wash with Care

If you wash your car or wheelie bin directly on the road, any chemicals you’re using will go straight into the drains on the road which lead to the river. However if you wash these items (and anything else) on your gravel drive or grass garden, you are adding a buffer which reduces chemicals heading to the river.

Resolution Five: Save Water

The more water you use, the more water needs to be abstracted from local water sources and treated by your local sewage treatment works. So by using less water, you keep more water in  the river for wildlife, but also reduce the volume which needs to be cleaned.

What are your New Year’s Resolutions for 2015? Let us know by Twitter or Facebook!

January 7, 2015   No Comments

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.

Motorbike

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.

Cake

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.

January 6, 2015   No Comments

Recruiting: Invasive Non-Native Species Officer

The Wandle Trust is recruiting a part-time Invasive Non-Native Species (INNS) Officer to help coordinate and deliver work to tackle aquatic INNS on the River Wandle.

Japanese knotweed

Japanese knotweed can shade out natural flora

INNS can have a negative impact on rivers by both directly out-competing native species and indirectly altering habitats, for example by causing the excessive ingress of silt which can smother the natural gravel riverbed.

The post is supported by the National Lottery through the Heritage Lottery Fund and is part of the Living Wandle Landscape Partnership, a programme which involves the local community in the restoration and enhancement of the River Wandle landscape.

The Project Officer will be responsible for the day-to-day implementation of the River Wandle Invasive Non-Native Species Action Plan and Work Programme.  The role will involve both coordinating the work of a range of partners and contributing to the delivery of the INNS Work Programme.

This post is now closed.

HighImpact logo CMYK

December 19, 2014   No Comments

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!

December 10, 2014   No Comments

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.

Siltex

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.

December 6, 2014   No Comments

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.

DiffusePollution

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!

December 6, 2014   No Comments