Howthwaite Grasmere Holiday at Howthwaite near Grasmere, Cumbria | The Landmark TrustManchester needed a new water supply and in 1878 the Corporation announced their plan to dam up Thirlmere, raising it by several feet and inundating or enclosing a large area of common land. The project, known as the Thirlmere Development, caused an uproar. https://www.landmarktrust.org.uk/search-and-book/properties/howthwaite-11481