Author Archives: Tim

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!

Hackbridge river restoration project underway!

After months of planning and preparation the weir removal and river restoration project at Hackbridge is finally underway!

Those of you who have crossed the road bridge over the river or walked along the Wandle Trail in the past few weeks will have seen big changes with heavy machinery in the river, the sound of breaking concrete and the sight of a river re-emerging.

Our skilled contractors Cain Bioengineering with site manager Nick and his team of Alex and Jimmy have been working hard to bring to reality our vision for the river.

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Gravel, stakes and hazel faggot bundles at the ready in the compound:

The work started with the removal of the heavily creosoted toeboarding from around the edge of the island.

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Toeboarding removed from the island and an old speaker found in the river!:

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The toeboarding still smelt strongly of creosote after many years in the riverbank:

A new island bank line was then created with hazel faggot bundles secured with chestnut stakes and backed with coir netting in order to extend the island and narrow the river.  Sediment from the channel (of which there was a lot!) was then placed behind the new bank line.  This sediment is a result of the weirs slowing the water flow and causing sediment particles to settle out and smother the natural gravel bed.

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Scraping sediment to place behind the new bank line:

After the creation of a new bank line parts of the island were regraded to create a gradually sloped bank that will be planted up at a later date with plants suitable for the different habitat zones created. The dead trees were retained as they are an important habitat for all sorts of creatures including bats, woodpeckers and invertebrates.

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Regrading the island with the excavator:

With the bed nearest the weir cleared of much of the sediment the weirs were breached and the process of breaking up the old weir structures begun.  The weir was found to be made up of cast iron plates, concrete, brick and lumps of chalk.  The cast iron was recycled and the proceeds will be converted into a pair of waders for our volunteer events!

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Smashing up the old weir:

Once the weirs were breached the water levels dropped upstream and the process of narrowing the channel was started with a combination of more posts and faggot bundles or stone.

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Forming a new bank line to narrow the river:

A sinuous meandering channel is starting to take shape and will allow for a variety of depths and flows with deeper faster flowing outside bends and shallower slower flowing inside bends providing varied habitats.

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Starting to take shape:

There have been many practical challenges along the way with sewer pipes, water mains and electricity cables criss crossing the river to be identified and avoided.  The joys of urban river restoration projects!

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Locating an electricity cable:

Look out for more updates as the work takes shape over the next week!

We will be holding a number of planting events to plant the island with native plant species in early September so please get in touch if you are interested in getting involved.

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.

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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.

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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

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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

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

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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.

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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

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

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

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Then a scoop or two of wood chip…

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

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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.

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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.

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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.

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

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Thanks to everyone who braved the inclement weather!

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

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at Wandle Bank

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Butter Hill

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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.

Hogsmill eels get a helping hand

Volunteers and staff from the Thames Anglers Conservancy and the Zoological Society of London (ZSL) joined forces this week with the Wandle Trust to help eels enter the Hogsmill River that runs through the centre of Kingston.

The European eel is now considered Critically Endangered due to the drop in the number of young eels (elvers) entering our rivers. It is a wonderful and iconic species with a life cycle that encompasses a 10,000 km round trip from the Sargasso Sea. Despite being such a long distance traveller eels aren’t particularly good swimmers .Volunteers from Kingston University, with the support of ZSL, have been monitoring the number of elvers (young eel) migrating up the Hogsmill and are yet to find any.  A possible reason for this is that they can’t get past the steep smooth concrete channel under Clattern Bridge.

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Richard making some adjustments at the top of the weir

By adding special ‘eel tiles’ to the riverbed that give the eels something to crawl through we hope that we can help them enter the Hogsmill. If we can open up all of London’s rivers more eels will grow to maturity in London meaning more will be able to swim back to the Sargasso Sea to breed.

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Attaching the eel tiles

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Eel tiles in place

It was great to be able to work in collaboration with TAC and ZSL. By working locally on our rivers we are able to make a difference on an issue that goes far beyond our shores.

Many thanks to Dave,  Keith, Richard  (TAC) and Joe (ZSL) for their enthusiastic help with this project!                                                             TAC image zsl logoWandle_Trust_Logo_HighRes

Come and join in some Balsam Bashing this Sunday!

Sunday 4 August 2013: Culvers Avenue, Hackbridge SM5 2BE

Beddington Park July 2012 _13_

One of the Wandle Trust’s big river restoration projects starting this year will be at Hackbridge, thanks to generous funding from DEFRA’s Catchment Restoration Fund.  However, physical improvements to the river cannot commence until the Himalayan balsam is brought under control.   So, we will be running a Balsam Bashing day there on Sunday 4 August.

The event, which will take place between the usual 11am and 3pm, meeting just off Culvers Avenue, Hackbridge, L.B. Sutton, SM5 2BE.

For more information and location please click here

 

Wandle life: Purple Loosestrife

I often blog about pollution and work we are doing to improve what is wrong with the river.  However, there is a lot of wonderful sides to the Wandle too!

This is the first of an occasional blog on the life found in and around the Wandle for you to look out for…

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Purple Loosestrife on the banks of the Wandle at Butterhill (Carshalton)

It is time for the beautiful Purple Loosestrife (Lythrum salicaria) to be seen flowering on the banks of the river. This  plant is a perennial plant loved by bees and butterflies.

It was used in the past as an astringent medicinal herb to treat diarrhea and dysentry.

Keep your eye out for a splash of beautiful purple as you walk or cycle along the river banks!

Wandle Park Revival, 6th July

2,000 visitors were predicted to attend the Wandle Park Revival event on Saturday 6 July, but the lovely weather attracted over 7,000 people and the Wandle Trust was there too, appropriately located right next to the river!  Dozens of interested people stopped by to ask questions and share reminiscences of their childhood in the park before the river was buried in a concrete pipe, and we chatted to young and old alike and handed out lots of copies of the Wandle vision document.

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Meanwhile, moustachioed gentlemen in top hats rode penny farthings along the footpaths to the sound of a harmonica and percussion from a traditional one man band,

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and as the sun rose higher in the sky, children and dogs automatically gravitated towards the water for a paddle.

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Following Croydon Council’s £3.5million transformation of the 123-year-old park that has returned the River Wandle to the surface for the first time in 40 years, the park’s Victorian splendour has been brought back to life and a host of new and improved facilities have been created.

The three year scheme, made possible by the Heritage Lottery Fund (HLF) and Big Lottery Fund (BIG) Parks for People programme, has also restored the bandstand, water-fountain, ornamental planting and boating lake, plus created a new skate park, ball court, open-air gym, pavilion and community garden, all set against the backdrop of the Wandle.

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Some 50 stalls and stages provided a wealth of entertainment for the crowds, and during the day three plaques were unveiled at the new bandstand by The Mayor of Croydon, senior Croydon councillors and Wesley Kerr of the Heritage Lottery Fund (HLF), which provided £1.9m towards the project. The scheme was also supported by £400,000 from Mayor of London Boris Johnson’s Help a London Park scheme, Croydon Council’s ‘Parks to be Proud of’ initiative, and Barratt Homes as part of their neighbouring New South Quarter housing development.

Pollution in Pickle Ditch, Merton

There is a blocked foul sewer in the Pickle Ditch at Priory Retail Park in Merton which is causing raw sewage to leak into the river.  Thames Water have responded promptly and have deployed aerators where the Pickle Ditch meets the Wandle.  They also have tankers at St Georges Avenue overpumping the blocked sewer. Our thanks to Thames Water and the Environment Agency for their quick response.

Although there are  a number of reasons this sort of thing happens, one of the main causes is fat blockages. We can all help stop these things happening by never pouring oil or fat down the drains! Always dry wipe your plates, cooking tins etc.. before washing up.