Located in Minqin County of west China's Gansu Province, the reservoir has a capacity of 99.3 million cubic meters and is used to irrigate an area of 879,100 mu (about 58606.7 ha).

Since last year the reservoir has become increasingly dirty as fresh water inflow dropped and more pollutants flowed in.

The water resources department in Gansu decided to tackle the problem by diverting 30 million cubic meters of Yellow River water and gradually draining off polluted water.

On April 16 last year, over 10,000 kilograms of dead fish was spotted floating in the reservoir, and the problem occurred again on March 20 of this year.

Zhang Xiansheng, who makes his living breeding fish in the reservoir, said that even three years ago the reservoir was clean enough for people to swim in. But now the water is often black, afloat with dead fish and pollution.

Hongyashan Reservoir is located on the lower reaches of Shiyang River, and receives less water every year because of other reservoirs upstream.

The average volume of fresh water flowing into the lower reaches has decreased from 542 million cubic meters in the 1950s to 84 million cubic meters in 2002, severely reducing the reservoir's ability to self clean.

However, the volume of waste water into the reservoir increases year by year. Last year, Wuwei, a city at the upper reaches of Shiyang, discharged 29.33 million tons of waste water into the Shiyang River, an increase of 84 percent on the 13.43 million tons in 1998.

At present, one-third of Hongyashan's inflow every year is polluted waste water.

In order to reduce pollutant input in the Wuwei region of the Shiyang River, Gansu water will invest 150 million yuan (US$18.1 million), and is considering legally protecting the river by regulating pollution.

(People?s Daily May 28, 2003)