Author Archives: Bella

Wandle cleanup: June 2018: Wandsworth

For June we headed to Ravensbury Terrace in Earlsfield, Wandsworth.

At this event, Polly was accompanied by myself (Hannah) and Lucy. We will be taking over from Polly and running the cleanups from July 2018. This month was our chance to learn the ropes!

We kicked off the day in the usual style, with a Welcome Talk and Health & Safety briefing. It was a wonderful warm and sunny day, so it came as no surprise that everyone seemed keen to get wading shortly afterwards.

We had a great turnout, with around 50 volunteers working in and alongside the river. Whilst removing litter, some of the group concentrated on removing Himalayan balsam, an invasive plant species, from the river banks.

Here is the before and after!

Although we had recently visited this site back in January, the group quickly found our first big item – a Boris bike!

Followed by… another bike!

As the day went on, we found some other interesting items including a driver’s license, a teapot, a gold watch, coconuts, and a raccoon (don’t worry, not a real one), which Polly gave a new home.

Our break for lunch was a nice opportunity to cool off, drink some water and of course fill up on some cake.

The second half of the day was spent removing anything we had missed, and we found some wooden desks, and this teapot!

So what did we find? 1 VHS, 1 carpet, 1 speaker, 1 scooter, 1 Disney art box, 1 teapot, 1 raccoon, 1 bracelet, 1 watch, 1 driver’s license, 1 bucket on wheels, 1 trolley bag, 2 bikes, 2 footballs, 2 coconuts, 2 golf balls, 2 wooden desks, some silver piping and lots of glass and plastic bottles, food wrappers, plastic bags and bits of cloth – and bags and bags of other junk.

We also spotted a Cinnabar moth, which I had never seen before (thanks Dave)!

See you next month!

Hannah and Lucy

Huge thanks for the warm welcome, and to everyone who helped unpack and pack up the van during the event, Wally and Maddy for supervising the Event Tent, and Wandsworth Council for organising collection of all the rubbish the next day, Big Yellow Wandsworth for providing free storage space for our equipment and to our funders, Tesco!

Thank you to all our volunteers for coming:  Aaron, Alison, Anne, Bridget, Charles, Chris, Dave, David C, David D, Derek, Ed, Eiryn, Ethan, Garth, Gemma, Gideon, Guy, Hugh, Ian, Jack, Jane, Jason, Jeffrey, Jo, Joanne, Joe, John, John, Luke, Madeline, Mark, Martin, Nick, Nicola, Paul, Per, Phil, Raphael, Robyn, Rory, Sally Ann, Sheila, Simon, Steve B, Steve N, Suzanne, Thomas, Wally and William.

The Wandle’s a Winner!

After

We’re delighted to announce that we are a category winner in the 2016 UK River Prize. The Carshalton arm of the Wandle has won the ‘Urban Project’ category and is one of four category winners who will now go forward as finalists for the overall river prize.

The overall UK River Prize will be announced at an awards dinner at the River Restoration Centre’s Annual Conference in Blackpool on the 26th April.

You can read the River Restoration Centre’s press release here (UK_River_Prize_Finalists) to see the other category winners and finalists who we’re up against. Each finalist will make a short video about their project which will be shown at the awards dinner.

Keep your fingers crossed!!

Recruiting: Part-time River Education Officer

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We are recruiting a brand new position at the Wandle Trust!

This part-time Education Officer role will deliver our Living Wandle Landscape Partnership Scheme Education project. The role will involve developing education packs about the River Wandle and a ‘Wandle in the Classroom’ programme to enable school children to help rear river plants and animals and release them into the Wandle.

Further details are available here: EducationOfficer_JobDescriptionFeb2015.

To apply, please send email a CV (2 pages max) and a covering letter (2 pages max) focusing on your relevant experience, knowledge and skills, before 5pm on Monday 6th April.

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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.

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.

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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.

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!

A little light goes a long way…

Our restoration projects along the Wandle are all progressing well, and it is time to introduce the next site on our list: the Ravensbury Park Back Channel.

The Ravensbury Park Back Channel is a remnant of the industrial milling era along the Wandle. Back channels, or “by-pass channels” were used as a mechanism to control the water passing through a mill allowing us to increase or decrease the flow depending on how much power was required. Although no longer used for this purpose, the back channel at Ravensbury Park has become part of the park’s landscape and could offer a valuable refuge for wildlife in the Wandle; in particular fish which could use the channel to by-pass the weir.

So what’s the problem?

  1. Channelisation

Like so many urban and rural rivers, the Ravensbury Park back channel has been engineered and modified to contain the river within a predetermined channel. This removes habitat and creates a stream with little variation.

Wooden banks and channelised nature of the stream

Wooden banks and channelised nature of the stream

  1. Un-natural banks

To protect the surrounding landscape from flooding, the natural sloping banks of this stream have been replaced with concrete and wood. This creates a ‘hard-edged’ bank and prevents important natural communities of marginal and aquatic plants from establishing here. A more gradually sloping vegetated bank provides habitat for many different species of riverine wildlife. Without this habitat there is a significant loss of biodiversity.

Concrete banks

A high concrete bank removes all interaction with the stream ecosystem.

  1. Little light

The Ravensbury Park back channel suffers from low light levels due to a dense tree canopy. This canopy limits the growth of aquatic plants both around the stream as well as within the stream.

A dense vegetative canopy prevents aquatic plant growth

A dense vegetative canopy prevents aquatic plant growth

Each of these issues on their own have negative consequences, but combined they significantly impact on the ecological structure and function of this little stream.

What can we do?

Over the next few months, the Wandle Trust will be taking steps to restore the Ravensbury Park back channel. This work is being funded by Defra’s Catchment Restoration Fund, and is also part of the Heritage Lottery Funded Living Wandle Landscape Partnership.

The main aim of the restoration works will be to create new habitats both in the stream and along the margins that will support fish, invertebrates and birds. More importantly, our works will provide a favourable environment for both aquatic and marginal plants which are a fundamental source of food and shelter for some organisms; vital for a thriving ecosystem.

We will be working further on our plans for this stream so keep your eyes peeled for new updates.

 

Welcome to Polly, Luke and Olly! (and sorry to Norfolk’s rivers!)

In the past few weeks we have had three new members of staff join the Wandle Trust & SERT team.

Polly Bryant joins us from Norfolk County Council and will be running our volunteer events; Luke Mitchell, who has been undertaking research on the River Stiffkey in Norfolk, will be working on river restoration projects – you may well bump into him in Ravensbury Park; and Olly van Biervliet, previously at Norfolk Rivers Trust, will be picking up our water quality projects from Claire.

(Whilst we’re very sorry to see Erica move on – at least she’s moving to Norfolk!)

Within half an hour of arriving at the Trust, Polly, Luke and Olly were already getting stuck into our river restoration work at Hackbridge!

Luke, Polly and Olly get stuck in!

Luke, Polly and Olly get stuck in!

Hackbridge river restoration – the work progresses.

The river has continued to change quickly as our skilled contractors from Cain Bioengineering bring to fruition our plans. Nick, Jimmy, Alex, Will and James (with the occasional visit from Pete) have been working hard to continue the bank formation, backwater creation and island regrading with diggers, faggot bundles, stone, gravel and a lot of hard work.

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The Cain Bioengineering crew hard at work:

This has resulted in a narrowing of the low flow channel and increased flows instream.  The narrowing and meandering river channel brings a lovely diversity of flow to the river which is important to give different habitats for different species of fish, plant and invertebrate life.

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Increased flow diversity brings increased habitats:

As the work progressed the rivers natural gravels were revealed by the increased energy of the water and the working of the bed.  the gravels vary in size from very small to ‘cow skull’ size pieces of flint.  It is amazing to think that many of these gravels have probably not seen the light of day for hundreds of years!

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Natural Wandle gravels:

A causeway has been  built which creates a separation of the river from the backwater pond area.  A bed of stone was laid onto which coir geotextile (appropriate considering how many coconuts we find in the river!) was laid. Gravel was used to weight the coir down and then silt and sediment from the pond area was laid over this and the coir folded and sown shut to create, in essence,  a large sausage like growbag!

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The making of a causeway:

More silt and sediment was then overlaid ready for planting up with marginal plants.

The electricity cables were eventually spiked and cut to prove that they were indeed abandoned and this then allowed work to commence on the removal of the 3rd weir below the footbridge.

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Proving the electricity cables are dead so we can excavate the bed:

The breaker soon made short work of the concrete and brick structure and the river was free of its last obstruction (around Culvers Island that is!). Soil from the island and sediment removed from the backwater pond area was placed onto the new banks ready for our planting events on 6,7 and 8th September.  There is still space to attend if you would like to. Contact Erica Evans at Erica.Evans@wandletrust.org to sign up.

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The third weir bites the dust:

Many passersby have commented on how clean the river now looks as the silt has been shifted and the clean gravels are seen. The increased water flow and movement is important in increasing oxygen levels in the water too. The Heron loves the work and has been seen at all times of day feasting on the thousands of tiny fish in the area.

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The heron enjoys it’s rich feeding grounds:

The Contractor’s work will soon be finished – watch this space for a final update!

Then it is onto the planting and hopefully good growing conditions this autumns!