Banging the drum against road runoff at the UK Rivers Summit

Banging the drum against road runoff at the UK Rivers Summit

Brown trout were able to return to the River Wandle and breed successfully for the first time in nearly 100 years thanks to the South East Rivers Trust’s work, Co-CEO Dr Bella Davies told the UK River Summit on Tuesday. Ian Lamont, our Communications Officer, reports.

An enthralled 100-strong audience at the second annual Summit heard that road runoff had been stopping trout spawning on the Wandle. The summit brought together campaigners, NGOs, politicians and industry experts to debate issues affecting rivers, in the historic setting of the National Trust’s Morden Hall.

Dr Bella Davies talks at the UK River Summit
Dr Bella Davies talks at the UK River Summit about preventing road runoff

Bella explained that a mechanical device called a hydrodynamic vortex chamber – effectively a big drum – had proven to be the solution to help brown trout thrive once more. It had been fitted to key parts of the river to filter out numerous chemicals and pollutants before they reached the Wandle.

Bella urged a captivated audience at the Summit to “implore policy makers to listen, investigate and do something about,” road runoff because the “solutions are there” to stop contaminants from roads reaching our rivers. She outlined the struggles to bring back brown trout, an iconic species, to the special habitat of this chalk stream, one of only about 220 such rivers globally.

The trouble trout had in the Wandle

A “top predator” and “keystone species” in the eco-system, brown trout had struggled to thrive in the Wandle because of pollution, with the last one caught there in 1934. The industrial revolution was huge in bringing about that scenario, but modern day road runoff had become the modern culprit, she explained.

One of the first projects run by the Wandle Trust (which later became SERT) was Trout in the Classroom, said Bella. School children helped breed the species, but after the fish were released they did not breed successfully in the river, surveys proved, despite Environment Agency data showing that the water quality was high.

Those who saw the Wandle regularly noted that the water turned black every time it rained. Conclusions were drawn that the cause was road runoff. A commissioned study by a Queen Mary university student identified 15 types of Polycyclic aromatic hydrocarbons (PaH) pollutants and copper in the river.

So how could the issue be solved?

Road runoff pollution filter
A giant hydrodynamic vortex chamber filters our road runoff and sends clean water into the River Wandle’s Carshalton Arm

A hydrodynamic vortex chamber was selected to capture the pollutants before they reached the river – and a year after its installation another EA fishery survey found there were 67 juvenile trout on a 200m stretch of the river.

“Urban pollution and road runoff are one of the three main sources of pollution in Britain alongside agriculture and sewage. It is the reason that 18% of water bodies fail their target of good ecological health. It is also massively underestimated and under-monitored,” Bella explained.

She added that road traffic sends about 300 toxic chemicals, for example from catalytic converters in vehicles, into rivers via drains. Microplastics, tyre wear, paint, rust, pesticides, road chemicals and garden runoff are other examples of sources of such pollution washed in by the rain.

Bella said about road runoff: “It’s toxic and much of it can’t be broken down by micro-organisms in the water environment. It’s persistent and it builds up in the sediment and can affect the entire eco-system.

“The impacts of road runoff are widespread and very scary. We know they can cause harm to insects and to human health. The PaHs are particularly nasty – they can affect an animal’s ability to reproduce…and can cause death outright, especially in the summer when it hasn’t rained for a while. When it rains, we often see fish kills because the contaminants have washed straight into the river.”

Describing how the vortex chamber worked, she said that dirty water goes into the device at the upstream side, the “big drum” retains the sediment and then cleaned water is sent into the river.

These had never been retrofitted into roads before, so our project leaders worked closely with manufacturers to make them work and fitted them on to the three main surface water drains coming into the Carshalton Arm of the Wandle.

“That was the first time trout had spawned successfully on the river for almost 100 years,” Bella stressed.

Other solutions to road runoff, she said, included nature-based ones such as wetlands, such as the  Chamber Mead on the Hogsmill. Ideally both would be in place, with wetlands bringing amenity, flood and biodiversity benefits.

‘It gives me hope, but policy has to change’

Removing pennywort
Removing pennywort at Morden Hall Park during the UK Rivers Summit

Bella concluded: “These solutions give me hope that it is possible to tackle road runoff, but we need to do it everywhere. It is estimated that there are a million outfalls in the country and that’s probably underestimated. They are completely unmeasured and unregulated.

“I implore the policy makers to listen, investigate and do something about it. We have to shout louder to make sure this actually happens. We know there are effective solutions out there so let’s build them quickly.”

In her welcoming remarks, Bella invited people to “celebrate all rivers” but in particular the Wandle. “It’s unusual to be a chalk stream, it’s even more unusual to be an urban chalk stream and it’s even rarer to have one with a footpath all the way alongside it,” she said, referencing the Wandle Trail.

The Summit also gave us the chance to show attendees our volunteers’ work on the River Wandle at the National Trust-owned park. About a dozen people donned waders to cross the river and head to the main park for a guided river wade to see how our volunteers have turned a straight river into one flourishing with wildlife. Participants also had the chance to remove pennywort from the river next to Morden Hall, appropriately during Non-Native Invasive Species Week, which highlights how plants and animals that have come into our rivers cause them harm.

Click below to hear Bella’s full speech about the road run-off solution.

Riverflying the flag for healthy waterways

Lou Sykes, our Catchment Officer for the River Loddon, has recently recruited volunteers to undergo training for riverfly monitoring on this catchment for the first time. In this blog, she emphasises the importance of this monitoring, details what volunteers should be looking for and puts out a call for more volunteers across our wider river networks.

This year, the Loddon Catchment Partnership is focusing on investigating poor sources of water quality. We at the South East Rivers Trust (SERT) have conducted riverfly volunteer training to educate the public about freshwater invertebrates, as these creatures can serve as indicators of pollution.

Twelve volunteers have completed the riverfly monitoring training and are now regularly conducting surveys on the upper Loddon near Basingstoke to initiate the riverfly regime in this area. They are now part of a nationwide initiative to assess water quality in rivers. By consistently monitoring the river, they can identify reductions in water quality and report potential pollution issues to the Environment Agency.

So, what are Riverflies?

Volunteers checking a river sample
Volunteers checking a river sample for an RMI survey

They are tiny creatures that live in our rivers (hopefully!). Creatures such as mayfly have an evolutionary history going back hundreds of millions of years. They will spend most of their life in the water as nymphs or larvae feeding on plant life or algae.

They do important work, such as keeping things clean or stopping the build up of too much detritus.

Others are predatory and feed on other aquatic invertebrates. Some make cases from leaves, twigs, tiny pebbles and sand, acting as little underwater architects.

Others cling to rocks in faster moving waters. Some create little shelters in rocks and build little nets out of silk which they produce to catch food as it passes by.

Why are riverflies important?

Riverflies are often referred to as the canaries of our rivers as they are excellent biological indicators for monitoring water quality. The canaries reference comes from an era when mining for coal was a prevalent industry in Britain: canaries would be sent down mines before humans to test how toxic the air was. If the birds died, it was not safe for minors to enter.

Similarly, riverflies are sensitive to pollution, so finding them in the water gives us an indication of the state of the river. With Rivers Trust statistics showing that only 15% of rivers in England are rated in good overall health, riverfly monitoring is a valuable way to test the continued health of a stretch of river.

A polluted section of the River Loddon
A polluted section of the River Loddon

Riverflies live comparatively long lives as nymphs or larvae on the riverbed and are relatively localised within the waterway. The types of riverfly you can find vary based on habitat diversity, flow rate, water level and water quality, so you can tell how your river is functioning based on the groups that you find.

Monitoring for riverflies is a nationally important citizen science initiative (known as RMI), developed to monitor the health of rivers and to detect potential pollution events.

The Riverfly Partnership is a network of organisations, representing a wider range of stakeholders from anglers and water course managers to conservationists and relevant authorities that are looking to protect the water quality of our rivers and conserve riverfly habitats.

How  do we survey for riverflies and what are we looking for?

We survey for riverflies using a kick-sweep sample. Essentially, this involves kitting up in a pair of waders, grabbing a net and getting into the stream to ‘kick’ the riverbed and disturb the gravels to knock invertebrates living on them into your net. Your net is also swept through submerged vegetation to capture any invertebrates living in those, too. These, plus a hand search of large rocks or any other items that can’t make it into your net (yes that does occasionally mean the odd shopping trolley) make up the sample you look at.

This goes in a tray on the bank to be analysed, looking to estimate numbers of three key groups of riverflies: the up-wing flies or mayflys (Ephemeroptera), caddisflies or sedges (Trichoptera), and stoneflies (Plecoptera). We also assign freshwater shrimp (Gammarus) to this category too.

What’s next? Sign up to help!

A riverfly monitoring tray
A riverfly monitoring tray helps volunteers count numbers and types of samples

Having empowered our new volunteers on the Loddon, we are looking to expand and recruit more people to help monitor the health of rivers.

We have already lined up more training later this summer, for another group of volunteers on the Loddon catchment, giving more people the thrill of knowing they are contributing to vital data.

But we would like to know if you would like to get involved, across our 12 catchments (click through to a map to find your local river), which covers an area from Reading to Dover and down to Hastings.

Would you like to know more about the creepy crawlies living in your local river and what they show with regards to water quality? Could you spend a few hours each month monitoring a stretch of river?

We are interested in building a picture of potential volunteers, for whom we can design opportunities. Please get in touch on the below form to register your interest, so that we can understand how many people might want to be trained as riverfly monitors and where they are from.

Hundreds attend Chamber Mead wetlands opening

Hundreds of people attended Saturday’s Chamber Mead wetlands open day, many of them volunteering to start the mammoth task of adding 10,000 plants to the edges of this important pollution filter for the River Hogsmill.

The 2000m2 series of wetlands has been created to divert pollutants, coming from the Green Lanes stream, away from the globally rare chalk stream and will increase the numbers and types of wildlife across the Hogsmill Local Nature Reserve.

Egrets and ducks were already enjoying the wetlands as crowds gathered to hear Dr Bella Davies, Co-CEO of the South East Rivers Trust (SERT), explain the reasons for creating the wetlands in partnership with Epsom & Ewell Borough Council, which owns and manages the nature reserve.

Mayor cuts ribbon
The Mayor of Epsom & Ewell Rob Geleit cuts the ribbon to open the wetlands

The wetlands were then officially opened thanks to a ribbon being cut by The Worshipful Mayor of Epsom & Ewell, Councillor Rob Geleit.

In her speech, Bella explained that the project had been conceived more than a decade ago by the Hogsmill Catchment Partnership. This group of organisations and individuals wanted to address the issues of poor water quality in the Hogsmill. It is one of only about 220 chalk streams worldwide. Clear, cool waters in such streams should provide special conditions for creatures such as trout, eel and water voles to thrive.

“Many years ago we identified the Green Lanes stream was bringing poor water quality in. We discovered there was a whole load of urban runoff coming from Epsom,” Bella said.

“Surface water drains were sending [polluted] water straight from roads into the river – and that included lots of nasty things like hydrocarbons, heavy metals from tyres and catalytic converters and microplastics. In addition, there are misconnected pipes for example where toilets are plumbed in wrongly. People pour items down drains, there are pesticides from gardens – and all that is really toxic.

Volunteers start to plant up the wetlands
Volunteers start to plant up Chamber Mead wetlands

“There is another really big impact which came from the sewer storm tank overflows. Further up the Green Lanes stream there are two sewers that come together … and to stop them from backing up into your homes, there is a storm tank system where water flows up and theoretically goes back into the sewer. But in exceptional circumstances it overspills into the Green Lanes stream.

“Trying to fix that is really difficult,” Bella continued. “We worked with Thames Water to make the performance of the storm tanks as best as they could and they have reduced the number of times they spill massively.

“Another option is to clean the water before it goes into the river – and that’s what the wetlands are here to do.”

Plants are added to the wetlands
The public had the chance to added plants to the wetlands

About 90% of wetlands have been lost in the past 100 years, Bella added, and this nature-based solution would bring lots of other benefits. “It might look a bit raw, but it is a great time to see it [before plants are added].”

Trapping the silt in the initial pond was “really important,” she explained, because otherwise that silt smothers the river gravels in the water, restricting wildlife’s ability to thrive.

Contaminants coming from Green Lanes are also cleaned through the plants, before the cleaned water is sent back into the Hogsmill downstream of the popular stepping stones.

Multiple benefits of the wetlands include it becoming an attraction for wildlife such as damselflies and dragonflies, Bella added. It is also “really important” for local climate regulation. Those living near water experience lower temperatures which will be “really important” in hot summers in particular.

The wetlands cake by Heidi's Cakes
A special cake was created by Heidi’s cakes in Carshalton to mark the occasion

“There is also increasing evidence of the importance of nature for health and well being – and that’s amplified when we are near water. It helps decrease stress and also is a really great educational resource,” she added, referencing a new nature trail that has been put up around the site.

Delivering multiple benefits meant SERT, which leads the catchment partnership, has been able to appeal to a wide range of different funders. The development of the wetlands has  received funding from The Coca-Cola Foundation, Natural England (through the Species Recovery Programme), the Environment Agency, Surrey County Council, the Rivers Trust, the Zoological Society of London, Garfield Weston Foundation and Thames Water, with in-kind support from the landowner Epsom & Ewell Borough Council. The new wetlands are part of the wider Replenish programme in partnership with the Coca-Cola Foundation and the Rivers Trust. The aim of Replenish is to restore millions of litres of water in this and other local catchments, in turn improving biodiversity.

In total, about 300 visitors through the day had the chance to start the task of putting in vegetation around the wetlands and go on guided walks to hear more about the project.

Family friendly activities such as craft and the chance to explore what lives in the water through riverfly demonstrations were also available. Visitors also enjoyed a fabulous cake, baked to look like a wetland flush with wildlife, created by Heidi’s cakes in Carshalton.

Watch Dr Bella Davies speech in full below.

Your river needs YOU this May Bank Holiday weekend

We need your contribution from Friday 3rd to Monday 6th May, for the Spring edition of the Big River Watch.

Volunteers from across our region made a valuable contribution to the Rivers Trust’s first Big River Watch last September – and now your local waterway needs you again.

Whether you are an individual, a family, a group of friends or can organise formal group activities, we need your eyes on rivers to gather crucial data. You or your group don’t need to be a river user, just interested in your water-based environment.

BRW Poster 2024 Spring
Download this poster for the Big River Watch and encourage others to take part from 3rd to 6th May

We’re inviting all nature lovers across the 12 catchments served by the South East Rivers Trust to download an App and spend just 15 meaningful minutes connecting with nature.

What will you spot? Birds and animals in and around the water or vegetation below the surface can be a sign of healthy rivers. Meanwhile, you may see signs of pollution such as coloured water.

In September 2023, we were delighted that 223 surveys were submitted from across our region – stretching from Reading to Dover and down to Hastings – for the first UK and Ireland-wide survey.

There were a total of 3,600 surveys, with 5,871 people getting involved – 60% of them saying they were new to citizen science. So you don’t need experience, just enthusiasm and a love of nature.

Across our dozen catchments, 53% recorded at least one sign of pollution such as algae, livestock and road run-off, sewage and silt. UK and Ireland wide, 54% of people spotted some kind of pollution, but 73% felt their river looked healthy.

We know that looks can deceive, because across England and Ireland not a single river is classed as in good chemical health. Just 15% of river stretches in England are in good overall health. Chemical and nutrient pollution can be hard to identify, but can be very harmful to the life within the ecosystem. It can also hinder wild swimming and paddling and put people off using rivers for canoeing and other recreational activities.

A four day period including a bank holiday gives you and your groups plenty of time to take just a few moments along your nearest river to complete this biggest ever survey about them. The results will supply us with the data to locate the issues, pinpointing the priorities to improve our precious waterways.

Big River Watcher

As our handy map that helps you find your river shows, our area is wide, covering Berkshire and parts of Hampshire, Surrey, south London, Kent and much of Sussex.

So galvanise your group – residents associations, ramblers or youth group – and spring into action! Why not circulate the poster (attached) to encourage others?

The campaign again will be asking you how your local river makes you feel. Previous responses ranged from calm, happy and relaxed to concerned and sad at the state that rivers are in.

Last time you also submitted pictures of what you saw – from the good, to the bad and the bikes! Beautiful sunsets contrasted with the litter that was sadly often evident.

To take part, head to the Rivers Trust’s campaign page and download the App to submit results.

Chamber Mead wetlands recognised at sustainability awards

Chamber Mead wetlands and their importance to the River Hogsmill were recognised at the 2024 Edie Sustainability Awards in London last night (6th March).

The shortlisting in the Nature and Biodiversity Project of the Year category was a huge honour for everyone involved at the South East Rivers Trust as well as the partners who have helped make the 2,000m2  wetland a reality.

The wetlands were recently completed in Surrey on a stretch of the Hogsmill just south of London. They will filter pollutants and become a haven for wildlife protecting 5km of the river, which is a rare chalk stream.

Part of the Chamber Mead wetlands
Part of the Chamber Mead wetlands with the public bridge in the background

This is a fantastic example of a nature-based solution improving the condition of our rivers. The project has diverted a contaminated tributary into the wetlands, which act as a filter before reconnecting cleaner water into the Hogsmill downstream of the famous Stepping Stones.

One of only about 210 chalk streams in the world, the Hogsmill suffers from urban road runoff, raw sewage discharges and misconnected plumbing that sends drain water directly into the river. A healthy chalk stream’s pure water, stable temperature and flows provide longer growing seasons than other rivers and support important habitat for species such as brown trout and native crayfish.

Creation of the wetlands has been carried out in partnership with Epsom & Ewell Borough Council, which owns and manages the Hogsmill Local Nature Reserve, a popular greenspace which will now benefit from this new community asset.

Bella Davies, Co-CEO of the South East Rivers Trust, said: “We couldn’t be more delighted that the Chamber Mead project has been recognised by the Edie Awards. The project has been more than 10 years in development. It has brought together a wide range of partners and funders to step up and share responsibility for improving water quality in the Hogsmill river, one of the country’s rare and precious urban chalk streams.

Dr Bella Davies at the Edie Awards
Dr Bella Davies at the Edie Awards

“Wetlands such as these are a great way to improve water quality, especially in urban areas, in this case by filtering water from one of the Hogsmill’s headwater tributaries. This water has been contaminated by toxic urban road runoff and sewage from storm tank overflows and misconnected pipes. The water will now enter the Hogsmill after it has been cleaned by the wetlands and help bring back endangered river wildlife such as brown trout and eels.

“We’re also thrilled that the public will see the wetlands develop into a space where wildlife such as dragonflies, birds and butterflies can thrive providing more opportunities to experience nature on their doorstep.”

SERT is now preparing a series of planting days for schools, community groups and the public to take place in the Spring, as well as an open day to introduce the project to the community.

Supported by the Hogsmill Catchment Partnership, the Chamber Mead Wetland project has received funding from The Coca-Cola Foundation, Natural England (through the Species Recovery Programme), the Environment Agency, Surrey County Council, the Rivers Trust, the Zoological Society of London, Garfield Weston Foundation and Thames Water, with in-kind support from the landowner Epsom & Ewell Borough Council.

The new wetlands are part of the wider Replenish programme in partnership with the Coca-Cola Foundation and the Rivers Trust. The aim of Replenish is to restore millions of litres of water in this and other local catchments, in turn improving biodiversity.

Volunteer to tackle pollution on the Beverley Brook

Do you see pollution in the Beverley Brook and want to do something about it? Did you know that misconnected household plumbing is sending sewage water straight into our precious waterways?

Rivers should be healthy spaces for wildlife and places people can enjoy, but they are plagued by pollution – some of it coming straight from our homes.

This spring, you can become a citizen scientist and help us identify, map and assess polluted outfalls along the river, which rises in Cuddington Park, Stoneleigh, and passes through New Malden, Wimbledon Common and Richmond Park. This is all in partnership with Zoological Society of London (ZSL) for the latest round of their Outfall Safari programme.

A polluted drain spills into a river
A polluted drain spills into a river

Solving the problem of misconnections

Our drainage network is serviced by two systems. One collects rainwater and flows directly into rivers. The other takes foul wastewater from buildings to sewage treatment works to be cleaned first.

When appliances such as washing machines, sinks or toilets are incorrectly connected into the rainwater drainage system, this pollution spills directly into rivers. Signs of these plumbing misconnections can be as obvious as detergents or waste from toilets appearing in the water. These misconnections can become a chronic source of pollution with serious impacts on water quality and wildlife.

In 2016, ZSL created a method to survey London’s rivers to identify and report polluting drains. Before then, the scale of the issue was completely unknown. Now the method is used nationwide.

The results from volunteer surveys are reported via an App to the Environment Agency and Thames Water. The water company then addresses the misconnected plumbing with property owners or local councils.

What difference has it made?

Volunteers will learn to understand and identify pollution from drains on the Pyl Brook
Volunteers will learn to understand and identify pollution from drains on the Pyl Brook

Outfall Safaris on the Beverley Brook were last conducted in 2019. Then, 57 out of 196 drains (29%) were found to be spilling pollution into the nine miles of river which includes the East Pyl and Pyl Brook tributaries.

Emma Broadbent, Volunteer and Engagement Officer at the South East Rivers Trust, said: “We’re excited to be focusing on the Beverley Brook, because last time our volunteers surveyed the river they found a high number of polluting outfalls. We are eager to find out what the situation is now, five years on.

“We know from the work on other rivers that Outfall Safaris really work. Last year, we surveyed the Wandle, finding just nine polluting outfalls from 135 drains, compared to 2019 when we found 16 that were polluting the river. Signing up to take part is a valuable way for any river lover to make a difference.”

During training, participants will gain an overview of water quality issues in the catchment, learn how outfalls become polluted and will be given full instructions on how to assess them and report them via bankside surveys. There is no need to enter the water.

How do you get involved?

Training takes place on Wednesday 20th March from 1.30pm to 3.30pm at Worcester Park Library, Stone Place, Windsor Road, Worcester Park, KT4 8ES. Sign up here.

Participants must be aged 18 or over, attend the training in person and be able to commit to carrying out the Outfall Safaris in March and April. Specifically, you will need to be able to conduct surveys during dry periods, at least 48 hours after wet weather. This is to ensure any pollution is not masked or diluted by rainwater drainage.

Across London and the South East of England, Thames Water, ZSL and local volunteers have prevented 4,243 misconnected appliances from polluting watercourses: 23% of them were washing machines and 21% kitchen sinks.

If you have further questions email Sam Facey, ZSL’s training co-ordinator.

New Chamber Mead wetlands brings fresh hope for Hogsmill  

The South East Rivers Trust (SERT) has completed the construction of a 2,000m2 pollution filter which will bring major benefits to the Hogsmill chalk stream.

When planting takes place in the spring, the newly constructed Chamber Mead wetland will protect and improve 5km of river downstream, filtering pollutants and becoming a haven for wildlife. 

Chamber Mead wetlands during construction
The wetlands took shape during several months of construction

The project has been carried out in partnership with Epsom & Ewell Borough Council, which owns and manages the Hogsmill Local Nature Reserve, a popular greenspace which will now benefit from this new community asset. 

The wetland is a crucial project for the Hogsmill, which suffers adversely from pollution such as urban road runoff, raw sewage discharges and misconnected plumbing that sends drain water directly into the river.  

Water from the Green Lanes Stream has been diverted through a sediment trap and two wetlands. Filtered, cleaner water is then reconnected to the Hogsmill downstream of the famous Stepping Stones. 

News about the wetland’s completion comes in the week of World Wetlands Day, on Friday 2nd February. 

Dr Bella Davies, Co-CEO of SERT, said: “We are delighted that the construction phase of this important wetlands project has now been completed. It is destined to become a jewel in the crown of the Hogsmill Local Nature Reserve. The public has shown great enthusiasm for this project, and we will soon be calling on volunteers and community groups to add the plants that will really make the wetlands flourish as a magnet for wildlife. The water quality improvements that will result from the wetlands are designed to help the river become a healthier place for all, especially wildlife that thrive in a chalk stream, such as brown trout.” 

Councillor John Beckett, Chair of the Environment Committee at Epsom & Ewell Borough Council, said: “The council is committed to protecting and enhancing biodiversity in our borough, as per our Biodiversity Action Plan 2020-30.  This partnership project with the South East Rivers Trust will help to ensure that the Hogsmill Local Nature Reserve is a place where nature can thrive; from woodpeckers, hedgehogs and bats – to species whose numbers have dwindled such as water voles, fish and eels. We know our residents cherish this Local Nature Reserve and I hope that many can join the community planting days, which are a unique opportunity to be part of this fantastic project.” 

Michele Cooper, Environment Agency Catchment Coordinator, added: “In partnership with local communities, the Environment Agency is investing millions in chalk stream restoration projects across the country to foster more sustainable abstraction, tackle pollution from agriculture and the sewage system, and restore more natural processes.

“Chalk streams are precious habitats, havens for wildlife and highly valued by local communities and visitors alike. Together with our partners, we also continue to work hard to protect and enhance wetland habitats to benefit people and nature. Their future depends on collective action and this partnership project is therefore a much needed and welcome step towards addressing the many pressures these rare watercourses face.”

Part of the 2000m2 wetlands at Chamber Mead
The construction of the 2000m2 wetlands at Chamber Mead has been completed

SERT is now preparing a series of community planting days, to take place in the Spring. These will give residents the chance to plant the vegetation to help the wetlands counter pollutants.  

Schools, community groups and residents will be given opportunities to install plants that have been specifically selected to filter pollution, trap sediments and attract a variety of wildlife. Plants selected include yellow flag iris, ragged robin, purple loosestrife and brooklime.  

In time, SERT will also offer guided walks and outdoor education sessions for school children. A nature trail is planned for families to interact with the wetlands as they develop, alongside information boards which will detail the reasons why the wetlands were needed and the types of wildlife that should be attracted. 

The construction was carried out with Five Rivers environmental specialists.

Supported by the Hogsmill Catchment Partnership, the project has received funding from The Coca-Cola Foundation, Natural England (through the Species Recovery Programme), the Environment Agency, Surrey County Council, the Rivers Trust, the Zoological Society of London, Garfield Weston Foundation and Thames Water, with in-kind support from the landowner Epsom & Ewell Borough Council. The new wetlands are part of the wider Replenish programme in partnership with the Coca-Cola Foundation and the Rivers Trust. The aim of Replenish is to restore millions of litres of water in this and other local catchments, in turn improving biodiversity. 

 

The Chamber Mead wetland
The Chamber Mead wetland will become a ‘jewel in the crown’ of the Hogsmill Local Nature Reserve

Going down the drain in the name of plastic research

As part of our Preventing Plastic Pollution (PPP) project, the South East Rivers Trust carried out a trial by putting guards under drains in public streets, to collect and assess the types of litter that are ending up in rivers.  Hannah Dry, our Plastics Project Officer, reports.

Trialing new ways to prevent plastic pollution

Drain guards trial
Opening a drain guard to see what litter has been captured

Our work over the past three years for the Preventing Plastic Pollution project has involved many cleanups and litter categorising events, education sessions and workshops and setting up a River Guardians scheme.

These were to make the public aware of the problems caused by plastic in rivers and oceans and to help communities think about how they might reduce their reliance on single-use items, which accounts for 50% of the of the plastic that reaches oceans via rivers.

Another principal aim of PPP, however, was to investigate and trial innovative ways to prevent plastic reaching rivers in the first place.

One way in which we did this on the River Medway,  our section of the 18-partner PPP project, was to trial the use of drain guards on public streets. What goes down these public drains goes straight into the river. The idea was to capture litter, to see what types were common and to examine the scheme’s potential – if scaled up – to preventing litter reaching rivers.

We worked in partnership with Kent County Council to put in six drain guards around Maidstone town centre, installing them for a nine-month trial.

The problem with drains

Potential for scaling up drain guards
Monitoring took place regularly during the nine-month trial

Drainage pipe networks are complex. Ownership is fragmented between different organisations such as local authorities, water companies, internal drainage boards, highways authorities, businesses and private individuals. These bodies only maintain the drain, but the responsibility of preventing pollution sits with no one.

What we do know is that rainwater drainage systems are a source of pollution directly into rivers – and a lot of this pollution is plastic. Once in the river, it is difficult to remove, resulting in immense damage to the environment, organisms and affecting water quality – and finally ending in marine ecosystems.

Last June, we installed drain guards to capture the debris, not just to prevent it reaching the river network but giving us the chance to see what types of litter were common.

The guards – which were nicknamed witches’ hats because of their triangular shape – are made from a geotextile material and designed to sit beneath a drain grill to act as a filter, catching plastic litter and debris that are washed in through runoff.

Monitoring these drain guards every few months, we found that we had to fit new models in three of the drains after four months because of issues with cigarette burn holes. Emptying and categorisation of the litter occurred at every monitoring session throughout the trial. The purpose of the trial was to assess the feasibility and effectiveness of the drain guards in preventing litter getting into the drainage network and to assess their potential to provide a long-term solution for stopping plastic pollution from point source discharge outlets into the Medway.

What we found

Litter in a drain guard
Cigarette butts were the most common find when emptying drain guards during our trial

There is no doubt that plastic litter falls into our drainage networks from roads and pedestrian walkways. Plastic was found in every drain guard during every monitoring session. Over the course of the trial, the guards caught and removed more than 774 items.

The locations to trial the drain guards were chosen based on the footfall and on their proximity to amenities such as bar and pubs. That was exactly where we found the highest volume of litter, the biggest number of cigarette butts and bits of rubbish that can be directly linked to the consumer – such as lemon slices, plastic straws, and beer bottle lids.

This gave us the chance to assess the influence of amenities with the volume of litter in the drain as well as giving an opportunity to engage with passers by on site and to use the information later on to engage directly with pub/bar goers and owners.

The most frequent litter type, by far, was cigarette butts (423). Their filters are made from a chemical compound – usually cellulose acetate, a type of synthetic fibre. It takes years to break down.

The next most common item that we found were unidentifiable plastic items (172). These were too small to be categorised or too degraded, having been out in the environment too long. The strangest things we found were half a toothbrush handle and metal magnetic balls.

We also found 74 pieces of used chewing gum. It is common for chewing gum to contain plastic polymers such as polyvinyl acetate, which gives chewing gum its elasticity. Again, this means it will take a very long time to break down.

The items we found in the guards varied drastically between locations. Bottle tops, cigarette butts, straws and were all found in the guards outside pubs, whereas the guards placed on the high street next to shops typically collected items such as receipts and sweet wrappers.

Is there potential for scaling up?

Hannah before opening a drain guard
Hannah before opening a drain guard

The theory behind installing drain guards is sound – stopping pollutants before they become an issue for river ecosystems. However, the wider use of drain guards still, arguably, addresses the symptom rather than the cause of plastic pollution.

Consistent categorisation of litter during every emptying of drain guards is unrealistic, as it is time consuming and requires multiple people. Therefore, it is likely they would only be used to prevent plastic debris from entering river catchments. Yet this is still a very valuable function and something that we as a society must consider if we are to have any effect on the amount of plastic entering our rivers.

The complex nature of drain ownership and tailoring the size and shape to different sized drains, to ensure litter is collected more reliably, are also challenges that would need to be overcome.

And then there was the glamour factor…

This trial was not a glamorous one. A lot of the time was spent inspecting drains and counting very degraded and contaminated piece of litter that many people would find very disgusting. Not to mention the smell of the drains! Imagine sewers.

Yet it is necessary. Only by counting and categorising what we find down these drains can we then begin to understand the type and scale of the items and begin to think of ways to prevent it getting there in the first place.

There is too much plastic flowing into our rivers. Once it finds its way into a river, it is very difficult to remove. We need all stakeholders to take responsibility for the drainage networks and monitor and stop what is falling into them.

This trial provided data about what is entering the drainage network and how this differs between locations. It has tested different technologies to address this issue and highlighted areas where it could be feasible long term.

Tips for a sustainable holiday season

In an effort to improve the environment we live in, Preventing Plastic Pollution, one of SERT’s ambitious primary projects, focuses on reducing single-use plastic on the River Medway as part of a much wider effort across both France and England.

At this festive time of year, being aware of reducing our plastic waste is something everyone can – and should – take a moment to think about.

We asked staff at the South East Rivers Trust for their ideas and top tips for creating an environmentally friendly and sustainable holiday season, and below are their thoughts and recommendations.