Engineering a natural filter system to tackle pollution

IT’S not often the engineers who look after our roads get involved with wildlife-rich reed beds, but that is exactly what is happening on the A38 near the busy Newton Abbot junction.

Highways England is joining forces with Stover Country Park and Devon County Council to deliver a giant reed bed filter system, which will help to keep water clean at the popular Stover Lake nature reserve and provide valuable habitat for wildlife.

The sustainable scheme, also supported by Natural England, is designed to capture and filter water runoff from the busy A38, as well as from nearby industrial sites and farmland before it enters the lake.

The water can carry pollutants such as oil and metal residue into the lake and this has contributed to the poor water quality and reduced di- versity of wildlife. Reed beds offer a natural solution to the problem and around 3,800 sq m of the unique habitat will be planted upstream of the lake and its country park to act as a natural barrier and filter pollutants.

The area will also provide varied habitat for a range of wildlife. At the same time the park, which is designated a local nature reserve and a Site of Special Scientific Interest (SSSI), will be improving sustainable drainage at the site. Highways England project manager Darren Painter said: “When completed, this work will make Stover Park more enjoyable for visitors as well as tackling pollution and providing valuable habitat for wildlife. The twin reed bed system starts by providing a physical barrier to polluted water – then, following absorption, microbes work to break down even more

An artist’s impression of the completed scheme at Stover Lake nature reserve pollutants, resulting in clearer water which will help the lake to regenerate and flourish.”

It is hoped that by reducing pollution, white-water lilies – not seen at the lake since 2007 – will once again cover the water area, providing suitable habitat for a variety of dragonflies and damselflies.

The reed beds will also support a range of birds, insects, reptiles, amphibians and mammals including otters.

Rob Ballard, ranger at Stover Country Park, said: “The construction of the reed bed system will help the regeneration of the lake, its water plants and waterfowl. Visitors and school groups will be able to view the reed bed creation from a special interpretation viewing area.”

Councillor Roger Croad, Devon County Council cabinet member with responsibility for environmental services, added: “The council is rightly proud of Stover Country Park. It’s an important habitat for wildlife and is extremely popular with visitors so we want to ensure it provides the best possible environment.”

Work at the site will start later this month and is expected to continue for up to seven months. To create the reed bed 6,000 tonnes of soil will be removed, and four varieties of reed native to the area will be planted.

For most of the construction work it will be necessary to close the cycle path running through the park. Closures will be publicised in advance and posters showing a diversion route will be on display.

Some of the existing on-road drainage will be modified to connect with the reed beds, which will involve an expected eight nights of closures on the A38 or the slip roads.