Once sewers, UK's rivers are now the cleanest in 150 years

The quality of water in Britain has improved.Some of the country's  rivers were little better than sewers a generation ago, but are now the cleanest in more than a century.
 
Figures show that water quality has improved year on year for the past two decades, and serious water pollution incidents have more than halved since 2001.
 
In the past decade, British waterways have returned to conditions not seen since before the 19th century Industrial Revolution, the UK Environment Agency claims.
 
The improved quality of water has resulted in the return of wildlife species such as salmon, otters and water voles, reports The Independent.
 
It quoted Ian Baker, the head of water in the UK Environment Agency, as saying: "Rivers in England and Wales are at their healthiest for over a century, with otters, salmon and other wildlife returning to many rivers in record numbers in locations across the country. The last decade shows how far we've come in reducing pollution and improving water quality and river habitats."
 
A generation ago many British rivers were little better than foul-smelling drains. Such channels of untreated pollution are now largely a thing of the past, thanks to policing by the agency and investment by water companies, and also to the fact that most of Britain's heavy, old-fashioned smokestack industry, once the major pollution source, has disappeared.
 
River like the Thames in London, the Mersey in Merseyside and Greater Manchester, and the Tyne in Newcastle, are seeing a major resurgence of life.
 
This year the Thames beat hundreds of other rivers across the world to win the International Theiss River Prize, which celebrates outstanding achievement in river management and restoration.
 
The prize recognised the astonishing transformation which the river has undergone, especially since the introduction of treatment for London's sewage, which once was dumped raw into the river.
 
A 1958 survey at Tower Bridge found no fish in the river, the Thames is now home to at least 125 different fish species, including smelt and shad - while its estuary supports shellfisheries and is a nursery for commercial sole and bass stocks.
 
The Mersey, which once was also biologically dead, now also has a run of salmon and sea trout, while the river Tyne is now the most productive salmon river in England.
 
A new European law, the Water Framework Directive, will make ecological quality the new benchmark, and from 2015 Britain's rivers will be expected to be of "good" ecological quality.
At the moment, only 26 per cent of rivers in England and Wales hit that target, with 56 per cent of "moderate" quality, 14 per cent "poor" and 2 per cent "bad".