The National Botanic Garden of Wales is set on a historic parkland estate, dating back around 400 years. The heyday of the estate was in the early 1800s, when owner, Sir William Paxton, commissioned designers to create one of the finest Regency landscape gardens and water parks in Britain.
Water originally flowed around the estate via an artificial ‘necklace’ of interconnecting lakes, ponds and streams linked by a network of dams, sluices, bridges and cascades. By the mid-19th century, however, the estate had fallen in to a slow decline and the artificial lakes were eventually drained in 1934.
Although today little remains of Paxton’s landscape, in 1815 he commissioned artist Thomas Hornor to portray his estate in an album of watercolours. Hornor’s paintings have survived and, together with his accompanying narrative, are now being used to guide and inspire the National Botanic Garden of Wales restoration of the landscape as part of a £6.7 million project supported by the Heritage Lottery Fund.
Dam and river engineering specialists at HR Wallingford are part of a team using Hornor’s paintings to design infrastructure that will recreate the lakes, streams and cascades in the Garden.
HR Wallingford’s project manager, Alexandra Murphy, said: “We are using the historical landscapes captured by Hornor to inspire new dam and infrastructure designs that will allow us to reinstate the main reservoir (Llyn Mawr), a secondary smaller reservoir (Llyn Felin Gat) and bring the main waterfalls back to life. The landscape of the estate will be completely transformed.”
HR Wallingford will use the new Floods and Reservoir Safety Edition 4 Guidelines to calculate the spillway requirements for both dams, and will work with project partners Mann Williams on spillway design. The use of concrete grass systems will ensure that the spillway is sympathetic to its surroundings.
“Our challenge is to design structures that capture the essence of the original structures, whilst using modern design techniques and standards to ensure they comply with current legislation. We are also investigating options for hydropower schemes to generate renewable energy for use around the Garden,” said Murphy.