The new works, to be officially opened by the Prince of Wales today, were specifically designed to avoid spoiling the landscape, which is in a Site of Special Scientific Interest. The architects were instructed to study the design of a barn in a nearby farm.
As much as possible has been built underground, with both the treatment plant and the process tank buried. Passers-by see what appears to be a traditional "farmstead" (detail, left), arranged around a courtyard and built in the traditional Cumbrian materials of St Bees sandstone, split river cobbles and green slate roof.
Ennerdale Water has been supplying water to the people of west Cumbria since the last century, but the former treatment works had become outdated. As part of the project, North West Water has improved the "fish pass" which allows salmon and trout from the River Ehen to reach their spawning grounds in Ennerdale Water.
Photographs: Brian Harris