Evaluations and the Dowlais Free Drainage System
The Dowlais Free Drainage System is a complex drainage system, which supplied water to Dowlais Ironworks (Plates 14-15). It used a series of hand-built drainage channels called leats and natural watercourses to control the flow of water on the mountain. The leats and natural water courses connected a series of holding ponds such as the Sarn Howell, Longtown (Tre-hir) and the Soap Vein Ponds which controlled the flow of water to the Dowlais Company Ironworks. The watercourses ran both above and below the ground, which were inter-connected at predetermined points either to run out into the existing pond watercourse system or underground pondage areas to be pumped to the surface. From these ponds/reservoirs water would be taken to various mills and furnaces, within the Dowlais Ironworks.
The watercourse system was developed on Cwmbargoed Mountain from c1818, and the Sarn Howell Watercourse was in operation by 1839. By 1868 this unique system for channeling water had been completed. At this time, the Dowlais Ironworks was the largest in the world, and made use of large amounts of water for water balance winding gears at its mines, water power at the ironworks, steam engines, and cooling. Watercourse and reservoirs evolved into a uniquely large and densely developed industrial water control system which was described by John A. Owen in 1975 as ‘truly the work of genius.’
Two archaeological evaluations have been carried out so far, these involve excavating in 20x2m trenches placed to target archaeological features.
The evaluation of the area to the north of the Soap Vein Dam consisted of 1280m² of well considered trenching divided into 20m x 2m segments. The main focus of the evaluation was to identify any remnants of the Dowlais Free Drainage System (DFDS), preserved prehistoric landscapes and any unknown or unforeseen archaeological features or deposits. No trenches were placed on any features, such as the DFDS, which were already recorded in previous investigations (Roberts 2003). A rapid initial survey of 400m² yielded negative results; therefore, it was decided to extend the evaluation a further 880m². The additional evaluation again produced negative results.
The area around the Longtown Pond was evaluated by a series of 20m x 2m trenches (Plate 14). The trenches were positioned over potential archaeological features identified from maps and aerial photographic evidence. The evaluation identified several as yet unrecorded lengths of the DFDS and three small feeding ponds. A host of natural watercourses were identified and some were found to be interconnected with the DFDS. It would appear then, based on the evidence recorded thus far, that the builders of the DFDS utilised many natural watercourses and integrated them into their complex water management system. Immediately to the south of the Longtown dam as a brick valve house. This would have controlled the water flow from the pond down the leats and watercourses to the scheduled Sarn Howell Pond.
Finds
During the Longtown pond evaluation a prehistoric flint scraper was recovered and during the excavation of a water holding reservoir to the southwest of the Longtown Pond a broken flint arrowhead of probable Neolithic date was recovered from the ground surface.
Bibliography
Roberts, R. 2003. East Merthyr Reclamation Scheme, Phase III, Merthyr Tydfil: archaeological field survey. GGAT report no. 2002/075.
Owen, J. A. 1975. The History of the Dowlais Ironworks 1759 – 1936. Newport: Starling Press Ltd.