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Rhaslas Pond South Dam is a post-medieval dam located in Wales, constructed to impound water across terrain underlain by the Pennine Middle Coal Measures Formation and South Wales Middle Coal Measures Formation. The bedrock geology, formed during the Moscovian period, comprises mudstone, siltstone, sandstone, coal, ironstone and ferricrete—deposits typical of the South Wales coalfield that shaped the region's industrial development. This substantial water management structure reflects the exploitation of local resources and the hydrological demands of industry during the post-medieval period. The dam's construction takes advantage of the natural valley topography carved into these carboniferous strata. The monument is protected by Cadw under reference GM624, recognising its historical significance as evidence of early modern engineering and settlement patterns in the Welsh coalfield landscape.
Rhaslas Pond South Dam is a scheduled monument protected by Cadw under reference GM624. View the official record →
Rhaslas Pond South Dam is a post-medieval dam located in Wales, constructed to impound water across terrain underlain by the Pennine Middle Coal Measures Formation and South Wales Middle Coal Measures Formation. It is designated a Scheduled Ancient Monument by Cadw under reference GM624.
Rhaslas Pond South Dam dates from the post medieval period, and is classified as a dam. It is one of over 32,000 scheduled monuments protected across the UK.
Rhaslas Pond South Dam is a Scheduled Ancient Monument, legally protected by Cadw — the body responsible for designating and safeguarding heritage sites in Wales. The official designation reference is GM624.
Several scheduled monuments lie within 10 km, including Cefn Merthyr Round Cairns (7 km), Dyke 387m E of Clawdd Trawscae Farm (7.1 km), Coed Cae Round Cairns (7.4 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Rhaslas Pond South Dam's history, each drawn from the record and mapped to the exact spot:
Every location is different. Not every section appears for every place, only what the historical record actually holds turns up in a report.
Rhaslas Pond South Dam stands on Pennine Middle Coal Measures Formation And South Wales Middle Coal Measures Formation (Undifferentiated), bedrock that formed in the Moscovian. The rock here is mudstone, siltstone, sandstone, coal, ironstone and ferricrete.