The middle and lower reaches of the Yangtze River have moved into their rainy season. This type of weather, alternating as it does between rain and sun, adds to the charm of the West Lake.

The annual report on China's environment by the State Environmental Protection Administration (SEPA) came as quite a shock for those fascinated by the beauty of West Lake when it was released on June 5.

It showed a significant reduction in the water quality of the West Lake. Last year along with Donghu Lake in Wuhan, Hubei Province and Daming Lake in Jinan, Shandong Province it had dropped below Grade V.

The problem with the West Lake water is that it contains too much nutrient. The technical term is eutrophication (nutrient pollution) a condition of aquatic ecosystems where high nutrient concentrations can stimulate algae blooms.

Yu Xinhua, is head of the Hangzhou Environmental Monitoring Headquarters. He says the water quality in West Lake has not in fact changed significantly in recent years. The combined index representing a number of different measures has actually taken a turn for the better. Some of the various water quality indices for the West Lake have reached Grade IV, Grade III or even Grade II.

However, nitrogen content has always remained high, with this particular index regularly failing the Grade V standard as stipulated in the Environmental Quality Standard for Surface Water. The figures come from several local environmental monitoring sites.

But SEPA has now introduced a new more onerous method of evaluation. It is something of a "one strike and you're out" approach. It means that if just one of the full array of indices drops below its Grade V criteria then the lake will be evaluated as failing to satisfy Grade V.

This has led to a number of famous lakes around the country, including the West Lake to be downgraded for the first time to below Grade V for their water quality.

Yu Xinhua, a specialist in environmental protection, thinks pollution resulting from visitors, hotels and those who live around the lake can be readily dealt with. The real problem comes from a huge tea plantation beside the lake for this is the home of Longjing (Dragon Well) tea. It covers tens of thousands of mu (1 mu = 0.0667 hectares) and over fertilization with too much nitrate and phosphate fertilizers can be seen as the main culprit in the eutrophication of the lake.

In recent years the Hangzhou municipal government has moved to slow down the eutrophication of the West Lake. It has brought in such measures as dredging to remove silt, the prevention of sewage discharge into the lake and the Qiantang River diversion project.

"However solving the problem of eutrophication of the West Lake is not something that can be accomplished overnight," said Yu.

(China.org.cn translated by Zhang Tingting, July 8, 2003)