Best practice: the Thames
In 1957 the River Thames in London was so polluted that it was declared biologically dead, with little or no life able to survive in its noxious whirls. A survey a year later at Tower Bridge found no fish in the river. It is now said to be the cleanest it has been for 150 years and is one of the cleanest rivers to pass through a city in the world. Millions has been spent on upgrading and expanding water treatment works to deal with the city’s waste and strict legislation now prohibits the dumping of polluted effluent into the river. At the same time more than 400 wildlife habitats have been deliberately created and work has begun on ‘re-naturalising’ tributaries and streams that had been encased in tunnels or culverts to prevent flooding in the 1960s and 70s. The European Water Framework Directive now stipulates that by 2015 all of Britain’s rivers must meet its criteria for good ecological quality. At present only a quarter of the rivers in the country meet the target, which means the work continues. For example, London has a US$3.6 billion ‘super sewer’ in the pipeline that would prevent untreated sewage from periodically spilling into the Thames during rainstorms.