New Chamber Mead wetlands brings fresh hope for Hogsmill  

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

New online tool highlights nature-based solutions to tackle road runoff

A new online tool has been launched this week to help tackle road runoff pollution in London’s rivers by highlighting the best places to install nature-based solutions such as wetlands.

The development of the first-of-its-kind tool by Thames21 builds on years of research by the environmental charity and its partners Middlesex University and the South East Rivers Trust, which contributed with mapping, scoping and reporting.

Pollution from our roads adds to a number of problems for our rivers coming from sewer overflows, litter and misconnected drains. However it is often the Cinderella of pollution topics, because it receives far less public attention than sewage or agricultural causes.

Research from the Rivers Trust shows that the UK’s 1,600 rivers are affected by a cocktail of chemicals that are speeding up aquatic nature-loss, affecting insects, birds and mammals.

Road runoff goes straight to rivers
Road runoff goes straight to rivers

Road runoff can contain residue from oil spills, as well as tyre and brake wear from vehicles. These build up during dry weather and are then washed into rivers and streams when it rains.

The new tool will help decision makers prioritise the right water quality improvements:

  • in greenspaces that lie between the road and the river
  • at road locations in Outer London where surface water drains to the rivers; and
  • on London’s main strategic road network (includes Transport for London’s roads and some sections of National Highways’ and local authority roads)

Thames21 started its initial road runoff project identifying key polluting roads in 2019, with funding from the Mayor of London, Transport for London, and the Environment Agency. The British Geological Survey built the online decision support tool ‘Road Pollution Solutions’ and provided some additional support through the UKRI NERC-funded CAMELLIA project.

The South East Rivers Trust contributed research on sites in South London, including Surbiton, using its GIS mapping technology and catchment-based approach, identifying places where solutions such as wetlands could be built to counter the pollutants. By providing a natural barrier and filter using nature-based solutions, some of this road runoff pollution can be captured and prevented from entering rivers in the first place.

Users of the tool can search different boroughs, pinpoint particular areas and see just how polluting they are. This will help to prioritise where solutions could be put in place as mitigation. The tool shows the location of rivers, sewage outfalls and areas that drain into waterways.

Online road runoff tool example
An example of how the road runoff solutions user guide works

Modelling has shown that 2,415 road sections covering a total of 451.43km of London’s roads assessed pose a high risk of causing road runoff and are therefore a priority. Roads where heavy goods vehicles regularly apply their brakes are often the worst affected.

Community groups can also easily see pollution hotspots and help to suggest solutions by working for example with the authorities or through catchment partnerships.

The tool – which extends to all outer London boroughs – allows uses to access data by boroughs or river catchment and includes the Wandle, Beverley Brook, Hogsmill, Upper Darent, Lower Cray and Upper Cray.

Working in partnership, authorities responsible for these roads could intervene by providing nature-based solutions in these areas to help make runoff cleaner, and improve water quality in local rivers and watercourses.

Find out how the tool works by reading the user guide.