Natural dams restore Plynlimon’s wetlands

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22 JULY 2010NEWS RELEASE No: 13845

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The wild summits, rolling foothills and deep valleys of Plynlimon may be one of the remotest parts of Wales but the wetland areas and deep peat bogs provide the perfect habitat for a host of wildlife and plants.

Keeping the water levels right in Plynlimon’s wetlands and bogs is an essential part of the management of this vast landscape in order to protect and restore its special habitats.

One way to maintain water levels is to dam forest drains and – as befits such a rural location – Forestry Commission Wales, in partnership with the Environment Agency, has installed over 30 new dams made of straw and heather bales in the drains at Hafren Forest, on the slopes of Plynlimon.

The dams will slowly release water from the forest drains into the streams and rivers that flow across Plynlimon, instead of allowing a sudden rush of water as would otherwise happen after a heavy rainfall.

With the drains blocked by the dams, a peat layer will gradually build up creating a new peatland site that will become covered in heather and trees.

The dams are expected to last many years and, as they are made of natural materials, they will quickly become covered with grass and vegetation and blend easily into the landscape.

As well as protecting Plynlimon’s habitats, the dams will prevent the build-up of silt, which can cause damage to fish stocks, further downstream.

Forestry Commission Wales’s Local Area Manager, Jim Ralph, said, "The River Severn (Afon Hafren) has its source in a deep peat bog near Hafren Forest before setting off across the slopes of Plynlimon on its long journey to the Bristol Channel.

"Using these natural dams to restore the peatland in Hafren Forest will help preserve the special landscape character of Wales and also have benefits all the way downstream to Bristol."

The installation of the natural dams is part of a programme of work to improve the landscape at Plynlimon and follows the felling of conifers in Hafren Forest and planting of broadleaved trees such as birch and rowan.

Forestry Commission Wales works with a range of partners to manage Plynlimon including The Plynlimon Project, the Montgomeryshire Wildlife Trust and Environment Agency Wales which part-funded the installation of the natural dams in Hafren Forest.

Environment Agency Wales Biodiversity Officer, Charlotte Owen, said, "Environment Agency Wales continues to enjoy working closely with Forestry Commission Wales at Hafren Forest to restore internationally important peat habitat.

"It is hoped that the work will also serve to reduce flood risk lower down in the catchment, as well as improving our rivers to meet Water Framework Directive objectives."

Picture caption: One of the natural dams that have been installed at Hafren Forest

Forestry Commission Wales

About 14% of Wales is covered by woodlands. Of this, 38% (126,000 hectares/311,000 acres) is owned by the Welsh Assembly Government.

Forestry Commission Wales is the Welsh Assembly Government’s department of forestry and manages these woodlands on its behalf.

Forestry Commission Wales provides advice on forestry policy to the Minister responsible for forestry. It provides grant aid to the private sector and regulates forestry by issuing felling licences.

Forestry Commission Wales is also part of Forestry Commission GB and contributes to the international forestry agenda.

More information on the woodlands of Wales is available on

Press office contact: Mary Galliers,, 0300 068 0057.