Claerwen Reservoir

The Claerwen Reservoir and its dam stand in the uplands of Powys, Wales, as the largest and final addition to the Elan Valley Reservoir system. Built mainly of concrete with a dressed stone exterior, the gravity dam sits on solid rock foundations to balance the reservoir’s pressure. Completed in 1952, it was designed to blend with the valley’s earlier Victorian-style dams. Italian stonemasons were hired after British craftsmen were still rebuilding London in the late 1940s. The dam took six years to finish and is nearly twice the size of the other Elan Valley dams. The reservoir holds almost as much water as all the other Elan Valley reservoirs combined. Queen Elizabeth II officially opened it in 1952, one of her first royal duties as monarch. Water flows through an underground aqueduct to the Caban-coch reservoir before reaching Birmingham. The project required vast materials: over a million bricks, half a million tons of crushed stone, and 70,000 tons of sand transported from as far as the Severn Valley. Around 370 workers, including locals, laboured on site, housed in temporary camps or daily transported from Rhayader. Beyond the dam, the Claerwen National Nature Reserve stretches between Rhayader and Pontrhydfendigaid. Its peaty, acidic soils support rare plants like water plantain and carnivorous butterworts. The reserve also hosts breeding red kites and merlins. In 2015, the dam appeared on *Top Gear*, where Richard Hammond recreated a Land Rover advert by winching a vehicle up and down its face. The surrounding uplands remain largely untouched, offering quiet walks among oligotrophic lakes and raised mires.