Rivers are active systems and their direct ecological influence can often reach well beyond a recognisable riverbank. Where river valleys broaden, then periodically rivers will break their banks and flood surrounding low-lying ground. The areas affected are floodplains. They are particularly important habitat, sites periodically fed by flood water and river silt, and even went not flooded they have damp soils, and high water levels.     

 

Nationally, very little species-rich floodplain grassland remains. Most has been agriculturally improved and in the valleys of south Wales much has been lost to employment, road and residential development, and landfill. Within south Wales, unimproved floodplain sites are now very rare, however in RCT we are lucky to still have areas of species-rich floodplain grassland and the County Borough supports a network of species-rich and diverse sites. The best examples support intricate mosaics of dry and wet grassland, swamp and associated alder woodland and willow scrub and overgrown ditches. Management of floodplain and grazing marshes is essential to their conservation, conservation grazing or ‘cut and collect’ grassland management are important management tools. 

 

Recent work investigating the carbon holding capacities of different habitat types has shown that species-rich floodplain grasslands represent a very important carbon store. These same sites are also natural flood management sites which at times of high river flow can flood and protect houses and homes.  Conservation management to retain and enhance our species rich floodplain for biodiversity reasons is also delivering carbon sequestration and flood defence. 

  

Particularly important species-rich floodplain marsh occurs in the River Ely catchment at Pant Marsh, Pontyclun and Llantwit Fardre, and the SSSI quality floodplain wetlands of Coedcae Marsh, on the Nant Melyn at Talbot Green.  There is also more modified habitat in Pontyclun. On the Ewenny Fach, the Wildlife Trust owned Llanharan Marsh is a superb floodplain wetland.  Along the River Cynon, floodplain grasslands occur between Hirwaun and Llwydcoed, at Tirfounder Fields, the Wildlife Trust reserve at Pwll Waun Cynon and the adjoining Council’s wildflower area at Peace Park, Mountain Ash and at Abercynon. Although more agriculturally improved, there is also considerable floodplain grassland habitat potential in the Taff Valley which can be seen from the Taff Trail, and valley side view-points including the towering views of the Lower Taff from Craig Yr Allt or the Garth Mountain. Experience in nature reserves and the ecological renaissance of the Tirfounder Fields wetlands illustrates the capacity for greater restoration of floodplain habitats in RCT. If there is the potential for nature recovery, whilst also providing flood protection for downstream homes, this could be an excellent example of a win-win.