New fish pass opened on the River Derwent
'The Department for Environment, Food and Rural Affairs (Defra) said that Britain's rivers are the healthiest for over 20 years.'
This higher quality of water means that salmon, sea trout, otters, and other wildlife can return for the first time since the industrial revolution.
Over the past 25 years, baby eel stocks in rivers have fallen by 95%.
Mr Benyon said: "By allowing salmon and sea trout to return, this fish pass will create exciting new opportunities for fishing in the area and benefit the local economy."
The Environment Agency is also revitalising 9,000 miles of Britain's rivers by 2015.
The project will include habitat creation for endangered species such as water voles.