Agroup of lads stands in an excited huddle over a tiny pot. “It’s like a dolphin!” one of them exclaims recklessly as they peer through a magnifying glass at a shrimp barely more than a centimetre long flailing around in the water. But their excitement is not without some foundation - what they have caught is a burrowing mayfly nymph and you don’t see many of them around these parts. “Finding this is really good,” says Gwynneth Buss, an enthusiastic woman in waterproof and wellies, who is leading this minibeasts search in the Ladybrook stream. “They’re fairly unusual here and they need clean water.”

The Ladybrook valley cuts through the suburbs of Stockport, forming a ribbon of beautiful, gurgling waterside amid the hubbub. Many of this Year 5 class from Great Moor Junior School live locally, but few have visited the stream and some were unaware of its existence. Even their teacher, Paul Lewis, admits that though he “lives around the corner” from Ladybrook, he has not been there before.

Gwynneth Buss is one of the education officers for the Mersey Basin Trust, a charity which aims to help schools, voluntary organisations and community groups value and cherish the rivers and streams on their doorstep. Few people would associate Merseyside with any river other than the Mersey itself, but there are in fact 2000km of waterways winding through this region which is densely populated with six million people. Gwynneth Buss’s job is to raise awareness among schoolchildren about the nature of these waterways as part of a wider campaign to combat pollution.

The trust is in contact with more than 4,000 schools in Cheshire, Lancashire, Merseyside, Derbyshire and Greater Manchester. Great Moor pupils were taking part in the trust’s Water Detectives programme, which will reach more than 3,000 children and adults through the year. Armed with worksheets, nets and stopwatches, magnifying pots and metre sticks supplied by Gwynneth Buss, the pupils’ task is to measure the flow and depth of the Ladybrook stream, and hunt those “beasts” which are indicators of clean water.

Megan McDermott-Hughes, age 10, is certainly impressed by her tiny, wriggling, catch. “I didn’t know that anything lived in that river,” she says. Paul Lewis is grateful for having been shown an invaluable teaching resource “only half-an-hour’s walk from the school”. He says: “We would never have realised that this was so good unless we’d been told. We would have probably hired a bus to go further afield.”

Gwynneth Buss worked as a trust volunteer with schools for six years before recently becoming one of its education officers. She says: “Kids just love coming to these rivers and their enthusiasm is infectious. I’ve worked with some in inner-city areas who have never been to a stream before. They’ve just seen pictures in books. We try to take schools to the closest safe stream so pupils can have some sense of ownership. If my work makes one child have more respect for rivers then it is worth it.”

Although the Water Detectives project is mainly for primary schools, the trust also works in a more tailor-made fashion with secondaries and sixth-form colleges on ecology projects or comparing different waterway environments - a river source with flood defences, for example, for geography coursework.

The trust also runs StreamCare, acting as adviser to local groups that wish to adopt a local watercourse and take part in its long-term upkeep by removing litter; improving access; planting trees and wild flowers at the water’s edge; constructing footpaths and designing leaflets and signs.

The trust has its origins in the visit to Merseyside of Michael Heseltine, as Conservative minister for the environment, after the 1981 Toxteth riots. It was hard to imagine then that the Mersey and its tributaries, among the most polluted waterways in England as a legacy of the Industrial Revolution and the growth in the chemicals industry, supported thriving fisheries businesses in the 19th century, when salmon was the staple diet of the working man.

What followed Michael Heseltine’s visit, according to Caroline Downey, the trust’s executive director, was a rare example of government farsightedness, when in 1985 pound;4 billion was committed over 25 years to setting up the Mersey Basin Campaign. This brought all the major statutory environment agencies under its umbrella on the task of cleaning up the rivers to support fish, develop attractive waterside environments and encourage people to value the waterways.

The trust receives pound;80,000 a year in government grants, largely to support this undertaking. The campaign has been remarkably successful, with more than 90 per cent of rivers in the Basin now up to fair or good quality, and salmon have again been sighted, leaping the weirs at Howley and Woolston on the Mersey near Warrington.

But there is much work still to be done. The trust is presently seeking funding to extend its work by setting up links between schools and their neighbourhoods - local wildlife, landscape, residents and heritage groups - and using river projects as a basis for “active citizenship”. Rivers, says Caroline Downey, “do have a wow factor with children. The next step is to harness this natural enthusiasm and channel it towards actively caring for their local rivers and streams”.

Water and watercourses provide a link to exploring: Geography - in the study of river features, processes and systems. Human influences, both good and bad.

Investigative science - looking at living things in the environment, habitats, adaptations, variation and classification.

History - looking at legacies of Industrial Revolution, cultural heritage and working life.

Practical field work - applying methods and techniques of measurement and sampling to river processes and water quality.

Cross-curricular - links to maths, English, citizenship, global education and education for sustainable development.

Creative work in art, drama and literacy.

Water Detectives folders are available from the Trust free to schools in the Mersey Basin, plus pound;4.95 Pamp;P, and pound;5 plus pound;4.95 Pamp;P for other schoolsMersey Basin Trust Tel: 0161 620 8262Email: merseybasintrust@hotmail.com