Thirlmere, East Bank Looking North, Cumberland, 20th century. Thirlmere is a reservoir in the Borough of Allerdale in Cumbria and the English Lake District with a filter station and dam at the northern end. Constructed in the 19th century by the Manchester Corporation to provide the industrial city of Manchester with water supplies, the 96 mile-long Thirlmere Aqueduct still provides water to the Manchester area.
