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Natural Resources Wales (NRW) is considering the construction of a large centralised flood storage area along the banks of the river Cadoxton, just north of Dinas Powys to reduce the notional and mathematically modelled risk of flooding in the village. Flood management is clearly a complex issue that demands rational scientific thought, careful economic analysis and sound decision making. It must also respect national policy and reflect the concerns and views of local residents and the wider population. Many residents of Dinas Powys believe that the construction of a hard-engineered dam on an ecologically sensitive site would be irresponsible on a grand scale and hugely disproportionate to the small size of the catchment. We urge NRW to adopt smarter, natural flood management policies, not just in Dinas Powys but throughout Wales.

An empty pond in Workmans Wood, Sheepscombe, to collect and attenuate high flows on the Sheepscombe Brook.

 

Natural flood management (NFM) schemes help rivers and surrounding land maximise their natural ability to store or slow water. Examples include restoring river bends, increasing the number of small decentralised flood storage ponds and changing the way land is managed to enable soil to absorb more water. They do not include hard engineering approaches that work against or disrupt natural processes. NFM best when a ‘catchment based approach’ is taken, where a plan is developed to manage the flow of water along the whole length of a river catchment from its source to sea. Evidence for the effectiveness of natural flood management schemes is gaining significant ground. Sixty projects are underway in England, but, to the best of the author’s knowledge, there are currently only four in Wales. It appears that NRW was involved in the implementation of just two of these. In contrast, there are well over 1000 schemes in place across Europe.

Restored wet woodland at Sandall Beat Wood Site of Special Scientific Interest. (source: Environment Agency)

The project at Olway Brook in Monmouthshire involved the construction of buffer strips by local farmers along a 500m length of the watercourse. Since 2013, implementers recorded a reduction in sediment load in the channel, greater channel conveyance capacity, improved water quality and reduced flood risk. The Pumlumon Project in Powys is on a much larger scale, involving 40,000 hectares of the Cambrian Mountains. Measures included peat regeneration, moorland grip-blocking and natural flood storage areas. The project began in 2007 and embraces the principles of environmental sustainability, retention of natural beauty, improved wildlife diversity, clean water, carbon storage and natural flood control. The area has witnessed a rise in the water table, a large reduction in flood peaks in lowlands and an increase in wildlife. It is a very good example of working with natural process that are being adopted across the rest of the UK and across Europe, and is what we want to see more of in Wales.

Please do not underestimate the sense of hydro-citizenship in Dinas Powys and beyond. With over 1200 Facebook followers who are opposed to the construction of a hard-engineered dam, our residents want to work with NRW to find a more acceptable and sustainable solution to flood risk in this small area of Wales.

Don’t forget to join our Facebook group: Stop the Dam in Dinas Powys, or follow us on twitter: @stopdinasdam