Algae affects water supply in central China cities

CHANGSHA, Oct. 24 (Chinese media) -- Yellow algae emerged in

a major river in central China after days of lower than normal water levels due

to less rainfall recently and affected water supply in at least two cities.

The large amount of algae began to emerge in

filtering ponds of three plants of the state-owned Zhonghuan Water Company. The

buildup led to frequent blockages in the ponds, according to the Xiangtan

City-based company in Hunan Province.

Usually, the filtering ponds were washed every 24 to

36 hours. At present, they had to be washed each two hours in the most serious

situation, said Yuan Cheng, Zhonghuan Water deputy general manger.

Large areas of algae could be seen in the section of

the Xiangjiang River passing through Xiangtan.

Yuan said the city was experiencing water shortage

and its urban Hedong District only had a supply volume half its usual amount.

Apartments in high-rise buildings were suffering from low pumping pressure.

Hunan's main Xiangjiang River saw its water level hit

a record low 26.82 meters at 8 a.m. on Friday in Xiangtan, 0.04 meter below the

previous low.

The combination of the low water level, its high

content of ammonia and nitrogen, and the high temperatures of recent days had

contributed to the algae outbreak, according to experts.

After the summer flooding season, the river drainage

area only had precipitation of 16 mm, 64 percent less than the average in the

same period in recent years, according to the provincial hydrological resource

bureau.

Algae was also affecting water supply in Zhuzhou City

downstream. Monitoring by local environmental authorities showed the amount of

algae was 10 times greater than usual, affecting the city's water clarifying

plants in different degrees.

The plants had increased the amount of chlorine put

into the water to clean it before the filtering process, a Zhuzhou Tap Water

Company official said.

Polluting factories along the river were being closed

in such cities as Changsha, the provincial capital, to reduce pollution.

Two hydroelectric facilities, one upstream and the

other midstream, began to discharge more water downstream at 8 a.m. on Friday,

according the Hunan Provincial Flood Control and Drought Relief Headquarters.