MERTHYR Tydfil, Wales: A 226-year-old stone bridge that has been submerged beneath Llwyn-Onn reservoir since 1911 has re-emerged as Wales experiences exceptionally dry weather.
The two-arched bridge, believed to have been built around 1800, has now appeared twice in two years because of falling water levels. It was previously visible during the severe drought of 1976 and reappeared again in 2025, reports the BBC.
Natural Resources Wales (NRW) said Wales received only 8% of its long-term average rainfall for July, while many rivers were at “exceptionally low” levels.
Drought Reveals Hidden History
The unusually dry conditions have exposed several other archaeological and historical features across Wales.
The Royal Commission on the Ancient and Historical Monuments of Wales said heatwaves in June revealed traces ranging from prehistoric long barrows and forts to Roman buildings.
Among the discoveries were cropmarks showing a rectangular Neolithic long barrow in Welshpool, Powys, dating back about 5,000 years.
Archaeologists have also gathered new information about buried Roman buildings at Caerhun Roman fort in Conwy.
At Dinefwr in Llandeilo, Carmarthenshire, drought conditions revealed outlines of former Nissen huts.
The temporary structures were used during and after the Second World War, initially as a hospital and later as a prisoner-of-war camp. They were subsequently converted into temporary homes for local families during a housing shortage, creating a settlement known locally as “Tin Town”.
Environmental Concerns
The drought has not yet created an immediate threat to household and business water supplies, with Welsh water companies saying reservoir levels remain relatively healthy following a wet start to the year.
However, NRW said groundwater levels were falling in parts of Wales, with some below expected levels.
The agency said it was receiving reports of “wide-reaching impacts to the environment” and warned that conditions across Wales’ natural environment were continuing to deteriorate.
NRW’s Rhian Thomas said the effects of the prolonged dry weather were increasingly visible and that teams were monitoring weather forecasts and river flows.
“With no strong indications for notable rainfall in the forecasts, and risks of further heatwaves over the summer, it’s more important than ever that we all use water wisely,” she said.
“Every drop we waste is less water for our rivers and wildlife when they need it the most.”
The reappearance of the historic bridge offers a striking reminder of how extreme weather can temporarily uncover landscapes and archaeological features that have remained hidden for decades or centuries.
