Constant flooding and erosion had been causing some serious problems for Merthyr Tydfil Council who manage an old reclaimed tip site, close to the village of Bedlinog in the Taff Bargoed Valley.

Bedlinog after works, more natural flows
Bedlinog installing the VMax C350
Bedlinog, installing the VMax C350
Bedlinog naturalising the channel
Bedlinog post works with riffles and more natural flows
More natural flows after the works
Installing the VMax C350
Installing the VMax C350
Naturalising the channel
Post works with riffles and more natural flows

Constant flooding and erosion had been causing some serious problems for Merthyr Tydfil Council who manage an old reclaimed tip site, close to the village of Bedlinog in the Taff Bargoed Valley.

Hard channel before works was prone to flooding
Hard channel before works was prone to flooding
Bedlinog pre works
Before the works

Salix were brought in to do a full site analysis, design and implementation of a restoration scheme which would slow the flow of the Nant Llwynog, a concrete-lined channel that takes water from the mountains at high speed and in large volumes.

Salix were also tasked with stopping the flooding and erosion of the public footpath alongside the stream, whilst improving the habitat.

Salix proposed holding more of the water up at the top end of the park by desilting two of the ponds and by creating three new ponds linked to the main channel to attenuate floodwater. Salix also recommended reshaping the stone-lined channel to create a grass and reed-lined swale.

A channel through the middle of the large top pond was desilted and its exit to the swale was raised to increase attenuation capacity. Installing Rock Rolls and seeded soils in the stream bed, protected with an anti-erosion turf reinforcement mat, increased capacity at the top of the park. A new area of wet woodland was planted next to the new attenuation pond to further enhance biodiversity and reduce runoff.

To preserve the footpath, the second existing pond was also dredged and a new pipe installed to take excess water beneath the footpath to a new attenuating pond. Water from this wetland pond can pass back into the main channel further down the hill via another underground pipe.

By focusing our efforts upstream, the need for hard engineering was completely removed by controlling the velocity of the water in the park. This has improved the public amenity and biodiversity at the same time, and reduced erosion downstream.

Rolf Brown, Countryside Officer for Merthyr Tydfil County Borough Council said:

“The aim of the project was to better manage water through the park in a way that was environmentally, ecologically and visually beneficial. We approached Salix to devise a sustainable system that would minimise erosion in the valley and improve the landscape.

Environment Agency Wales – now Natural Resources Wales – favoured creating a more natural appearance to the existing engineered drainage channels, and grant monies were offered by them for reducing flash flooding impacts by slowing down water runoff by creating more ponds and wetlands and naturalising the stream course.

Several years on the installed system continues to prevent erosion, has ‘naturalised’ and is regularly visited and monitored by local residents interested in the improved biodiversity. The significant visual impact now makes the valley appear very natural rather than an obvious industrial reclamation site, and forms a key link between the village of Bedlinog and the Merthyr & Gelligaer Common Landscape of Special Historic Interest.”

Products Used

Pre-filled Rock Roll

Rock Rolls are a robust and permanent revetment for use around reservoirs, shorelines, lake edges, streams and river banks. They are cost-effective revetments that are suitable alternatives to rock rip rap and gabions in many scour applications.

Native Plants

Salix are the UK’s largest grower of native wetland and wildflowering plants in the UK – perfect for use in green infrastructure, peatland restoration, wetland restoration and creation and other habitat projects In response to demand for a wider range of species for specific habitat types we have developed a range of plug grown species for three key habitats: Salt marsh, Sand dunes & Moorlands. Wetland Plants Salt Marsh Moorlands Sand Dunes Salix are the largest grower of native wetland plants in the UK. Salix wetland nurseries have been designed and built specifically for commercially growing native wetland plants for supply

VMax³ Shear Stress Turf

Salix have the facilities to contract grow turf using the VMax range of Turf Reinforcement Mats (TRMs). VMax C350 or P550 is used as the reinforcement element within the turf giving unprecedented scour protection performance.


Client: Merthyr Tydfil Council
Location: Bedlinog, Taff Bargoed Valley
SUDS & Drainage Channels