The blistering heatwave that has scorched Wales has had an unexpected benefit – revealing long-lost archaeological sites across the country. A lack of rainfall in July, coupled with months of drought conditions, has led to the emergence of 'crop marks' which, when viewed from the air, expose hidden structures buried beneath the earth.
According to the Royal Commission on the Ancient and Historical Monuments of Wales (RCAHMW), Wales has experienced just 5% of its average July rainfall this year. The prolonged drought has also triggered severe grassland damage in some areas. As a result, distinctive patterns in vegetation have become visible from above – these 'crop marks' are created when plants growing over buried features access varying levels of moisture and nutrients, resulting in contrasting colours and growth.
Dr Toby Driver, an archaeologist with RCAHMW, has been leading aerial surveys from locations such as Haverfordwest and Caernarfon to document the fleeting discoveries. He notes that while these opportunities for aerial archaeology were once rare – occurring every five to seven years during 'record heatwave summers' – they are now becoming an annual occurrence. The team is racing against time, however, as these marks can disappear just as quickly as they emerge when the weather breaks.
Among the significant finds are a 5,000-year-old Neolithic long barrow in Welshpool, Powys; new details of buried Roman buildings at Caerhun Roman fort in Conwy; and 'parchmarks' of First World War practice trenches beneath a golf course at Deganwy, Conwy. A previously unrecorded Iron Age or Romano-British double-ditched farmstead has also emerged near Llandysul, south Ceredigion.
While the east and north-east of Wales have been particularly dry since mid-May, extensive heatwaves in late June have now affected grasslands nationwide. Dr Driver's team is utilising digital enhancement techniques to make faint crop marks 'pop' and reveal hidden details, ensuring these crucial historical insights are preserved amidst challenging windy conditions for aerial photography.