 The freshwater pearl mussel relies for part of its life on the presence of salmonids, a group of fish including salmon and trout.Sellafield has previously used water from the River Ehen for cooling on the site, but ceased this operation in the 1990s.There is a weir on Ennerdale Water, and as at 2016 the valley continues to be an important source of drinking water for customers of United Utilities in West Cumbria.