After the deluge, a dead river springs back to life

A small jewel-like river that had partially died because of drought and years of over-abstraction of water has been brought back to life by the autumn rains.

A small jewel-like river that had partially died because of drought and years of over-abstraction of water has been brought back to life by the autumn rains.

The river Misbourne in Buckinghamshire, which flows for 17 miles through the wooded hills of the Chilterns, had almost disappeared. It had been dry for more than five years on several stretches, and grass grew over its gravelly bed.

But the record downpours of late last year have recharged the aquifer, or water-bearing layer of rock, that feeds it to such an extent that it is now flowing strongly along its entire length, to the delight of the local people.

The Misbourne is a chalk stream, a type of small river typical of parts of southern England. Chalk streams are very lovely, very rich in wildlife - and very vulnerable.

Rather than being fed by rainwater running off the land, they are fed by water stored in and filtered by the porous chalk underneath them, which means they have a steady flow and temperature and a low acidity, and are crystal clear. As a result they support teeming insect life, plentiful fish populations, a profusion of aquatic wild flowers, colourful birds such as grey wagtails and kingfishers, and scarce animals such as water voles and otters.

But because the chalk is porous, if the water level in the aquifer drops they can run dry, especially if water companies, extremely keen to acquire water of such purity, take too much out in their boreholes.

This happened with the Misbourne, as it has with several of southern England's chalk streams over the past decade, such as the Darenth in Kent. In 1997 the Misbourne was virtually dry, with only a short stretch flowing at Denham, near where it joins the Colne, a tributary of the Thames.

However, a £3m restoration scheme set up by the Environment Agency with Thames Water and Three Valleys Water, the two companies that had been doing the abstracting, helped the river recover by piping in water for consumers from outside the area. But even early last month there were significant stretches in the picturesque Chiltern villages of Great Missenden and Chalfont St Giles that remained dry.

But the autumn rainfall, the heaviest since records began in Britain, eventually had its effect, and later last month the stream began a steady flow throughout its length. Not only that; it is now flowing from half a mile above what is normally regarded as its source, Mobwell pond north of Great Missenden; something local people say has not happened for 80 years.

"It's such a pleasure to see it flowing again," said Sarah Bentley, 28, who runs the Chiltern chalk streams project, set up by the management of the Chilterns Area of Outstanding Natural Beauty to champion the rivers that run through the chalk hills. "The week after it started again I went to the section that flows by the car park in Great Missenden, and people who had been shopping were coming over and peering in, saying, 'Oh, fantastic!' and 'Isn't it marvellous?' Everyone is delighted."

Some of Britain's chalk streams are world famous as trout fisheries. But, Ms Bentley said, chalk streams also represent an internationally valuable and rare habitat, which in Europe only occurs in southern England and northern France. "They're one of the most beautiful parts of the English landscape and superb for wildlife," she said. "They have a magical quality, partly because the water is so clear. They tend to be quite narrow and fast-flowing, so they are your traditional babbling brooks."

Her project, which is a partnership of 15 organisations including water companies, local councils and the Environment Agency, is intended to champion a group of smaller rivers. They include the Ver (at St Albans), the Gade, the Bulbourne, the Chess, the Wye (as in High Wycombe), the Hughenden stream and the Hamble brook. Several have run dry in the past, and the project aims to give them long-term protection.