Environment: China battles to revive its two sacred rivers

China has launched a massive pounds 18bn campaign to save the Yangtze and Yellow River valleys from ecological disaster. The project will take 33 years to complete. Teresa Poole in Peking asks if China is paying the price for its breakneck economic development.

Chinese poetry has waxed lyrical for thousands of years over the mighty Yangtze River and its sister to the north, the Yellow River. The fertile valleys are considered the "cradle of the Chinese nation", though the Yellow river is mourned equally often as "China's sorrow", because of its habit of bursting its banks and causing great loss of life.

A modern poet might find that other, less attractive, aspects of the landscape catch his eye these days. Nearly half the 2.5 million square kilometres in question is suffering from serious water and soil erosion, an official report at the weekend said. Trees have been cleared at such a rate along the river valleys that 1.6 billion tonnes of mud is carried down each year by the Yellow River alone, much of it washed down from the hills of the Loess Plateau which flank the upper reaches of the river.

In the middle and lower reaches, the riverbed is rising at a dangerous rate of 10cm a year as this silt is deposited, demanding a constant topping- up of the dikes which hold back the waters from flooding the surrounding lower land.

Stopping this alarming rate of soil erosion will the goal of the 230bn yuan (pounds 18bn) project. The answer is more trees. China aims to to plant 26 million hectares of forest by the year 2030, which, in theory, would cover just under two-thirds of the eroded areas. The population density in the valleys is so high that every possible strip of arable land has been utilised, and trees were chopped down long ago for fuel or cleared for farmland.

Bringing big projects to fruition is always a problem in China. But the central government has in recent years at last woken up to an environmental crisis which has overwhelmed the country, a crisis caused both by decrepit Communist industries and then by the economic boom of the past 20 years. This latest initiative marks the first time that the central government will fund more than half the cost of a major, long-term ecological programme. In the past, local government and farmers were held responsible for paying for forest-planting schemes.

China's two biggest rivers are the life lines of the country, running from sources high on the Tibetan plateau in Qinghai province and sweeping eastwards and downhill across the country. Together, the two broad valleys account for more than half China's total GDP output, and include some of the China's principal grain regions. Ambitious hydro-electric schemes, including the Three Gorges Dam on the Yangtze, have been started. But soil erosion is a huge problem for these power projects, too. The biggest challenge for the dams is the build-up of silt behind the dam walls and inside the turbines. The tree-planting campaign may help solve this.

This time, it should be clear quite quickly whether Peking is serious about its campaign. A pilot programme is due to take place in 100 counties this year. Each year, China's rivers present a destructive pattern of flood and drought damage, which China seems powerless to control. Each summer, central and southern China suffer terrible flooding which kills several thousand people. At the same time, the north-east runs short of water. The lower reaches of the Yellow River in 1997 notched up a record for the length of time the river ran dry in Shandong province, ruining the harvest in the heart of China's grain-producing region.