Conservationists have been given a 100 per cent score by civil engineers for their wildlife ecology work sprucing up old derelict east London waterways through the Olympic Park.

They’ve also been given a 92 per cent rating for ‘sustainability’ following the �2 million Bow Back Rivers regeneration project in the run-up to the summer Olympics.

The top rating was given to the Canal & River Trust by the Institute of Civil Engineers’ sustainability awards for 2012.

The work involved dredging four miles of silted-up channels, clearing choking weeds, removing wrecked cars, dumped tyres and other fly-tipped rubbish, as well as preventing soil erosion along the riverbanks running past the Olympic Stadium.

More than 80 per cent of dumped material such as metal, timber, old cars and electrical appliances was reused and 15 per cent recycled, while only two per cent had to be buried in landfill sites. The trust recycled nearly 38,000 tonnes of waste.

The waterways which are vital for flood management along the Lea River had become neglected, un-navigable and prone to vandalism and dumping over several decades.

Invading weeds like Japanese Knotweed, Giant Hogweed, Duckweed and Floating Pennywort were given their marching orders. This allowed oxygen levels in the rivers to rise, attracting fish and other wildlife.

New wildlife habitats have also been created, such as nesting sites and resting posts for specific species which include kingfishers and sand martins, while dead wood was used to encourage fish spawning.