Although relatively small in size, the valley of Thirlmere, formerly known as Wythburn, is dominated by its large reservoir and its looming, steep-sided fells. The bulk of Helvellyn hangs impressively over its eastern edge with the mighty Skiddaw and Blencathra to the north. Dunmail Raise to the south of Thirlmere is considered to be the boundary between the north and south Lake District. The famous cairn at the summit of Dunmail Raise is said to be the burial place of King Dunmail, the last monarch of the medieval kingdom of Cumbria, dating to around 945AD.
One of the best-known Lakeland archaeological sites is the stone circle at Castlerigg, just to the east of Keswick, which probably dates to Neolithic times and sits in the dramatic natural amphitheatre formed by the surrounding fells. There are also good examples of Neolithic rock art at Steel End and a Bronze Age ring cairn on Armboth Fell.
Today, it is the physical aspects of the water industry that stand out in the main valley. The Thirlmere reservoir is the most obvious of these but the dam infrastructure itself is considered to be of historic value. It was the first ever masonry gravity dam and one of only two arch dams in England and it supplies Manchester with water via a 96-mile long underground aqueduct. Other industries to impact Thirlmere were copper and lead mining as well as slate quarrying.
Thirlmere’s story includes the growth of the politicised landscape preservation movement, where the struggle between natural beauty and national interest was tested on a large scale for the very first time. The Thirlmere Defence Association formed in 1877 to oppose the flooding of the valley and the creation of the reservoir. Visionaries such as Canon Rawnsley and the social reformer Octavia Hill, influenced by the philosophy of John Ruskin, joined the fight. But Parliament voted in favour of the Manchester Corporation Water Works and the thirsty, fast-growing urban population in Manchester, and the dam was built. Today, United Utilities owns 4700 hectares of land in the Thirlmere Valley and the reservoir continues to supply around 11% of the water demands of the North West of England.
But despite the defeat, the battle was a significant moment in the history of the conservation movement, both in the UK and globally. It inspired the formation of the National Trust and it brought to a head the appreciation of the vulnerability of the Lake District landscape, and public access to it.
Thirlmere is also greatly important to the Romantic writers and artists movement and was the location for the ‘Rock of Names’ - the customary meeting point for the Wordsworths and Samuel Taylor Coleridge, and now reconstructed and relocated to Dove Cottage in Grasmere . Thirlmere was also the inspiration for William Wordsworth’s poem ‘The Waggoner’ and Walter Scott’s poem ‘The Bridal of Triermain’ and a place that continues to inspire visitors to this day.
Click here to see the full valley content from the World Heritage Site nomination document.