Chinese senior officials on Monday called for enhanced measures to curb lake pollution and facilitate lake rehabilitation at the 13th World Lake Conference that opened Monday in Wuhan, known as "the city of a hundred lakes".

Chen Zhili, vice chairwoman of the Standing Committee of the National People's Congress, China's top legislature, called for greater legislative powers to stop lake water pollution and to prevent lakes from disappearing.

Chen called for the establishment of special lake protection laws and regulations and implementation of strict judicial and administrative means in the management and supervision of industrial, agricultural and household waste, especially that of highly-contaminating facilities such as paper mills and chemical plants.

Lakes, a key element in sustaining ecological balance, remained fragile in the face of rapid industrial growth and increasing human activities, which led to serious contamination and shrinkage that in turn threatened people's living environment, she said.

China has more than 24,800 natural lakes. However, an average of 20 lakes disappeared every year, and about 88.6 percent of the lakes are in eutrophic state, she said.

Hubei Province, once known as "a province with 1,000 lakes," currently has 2,438 square kilometers of lakes, or about 34 percent of the total in the 1950s.

The shrinkage of water area, water pollution and the degradation of ecological functions are the major problems threatening worldwide lakes and bringing direct impact on people's lives and production activities.

Efforts must be taken to further restructure economic development and to eradicate outdated production methods that consumed enormous natural resources and produced massive waste, a main challenge to the fresh water ecological system, she said.

People should have a correct understanding of ecological characteristics of lakes, based on which industries and development scale by the lakeside are determined, she said.

Zhou Shengxian, China's Environmental Protection Minister, described China's water environment as still "serious", calling for more efforts to improve ecological functions of water environment.

A number of key lakes across China had suffered outbreaks of blue algae over the past decade, forcing local authorities to launch emergency treatment campaigns.

The government of Jiangsu Province realized in 2007, after an outbreak of algae in the Taihu Lake, that stopping waste discharges into the lake was more effective than just cleaning the water.

Two major outbreaks of algae in Erhai Lake in Yunnan Province between 1996 and 2003 triggered problems in drinking water supply. Six pollution control projects on waste treatment, soil erosion, water system restoration and public education had greatly improved water quality in the lake.

Japan's experience in protecting Biwa Lake from degradation, which involved limiting waste discharge, higher discharge and environment assessment standards, and strict requirements for the treatment of household sewage since the 1970s, also inspired China in lake pollution control campaign.

"Lake contamination exists everywhere in the world. Water stays in a lake much longer than in a river, so it can take 100 years to tackle a polluted lake. Cleaning up a lake needs many preferential policies from the government and costs much," said Masahisa Nakamura, scientific committee chairman of the International Lake Environment Committee, at the conference.

Chen Lei, Chinese Minister of Water Resources, admitted that the country is facing major challenges in low flood prevention capacity, shrinkage and degradation of lakes, and deterioration of water quality and ecological functions of lakes.

A survey in 2007 showed 27 of the 43 lakes surveyed suffered from eutrophication, and 12 of them seriously, Chen said.

He proposed to clean and renew the lakes by ways including waste prevention and treatment, connecting lakes with rivers, clearing silt, bio-tech management and comprehensive treatment of estuaries.

The minister also urged the establishment of laws on lake management and industrial development at an early date, while maintaining strict supervision and punishment over illegal activities.

He said the Chinese government supports technological innovation to enhance lake protection and development.

"Tackling lake contamination needs a long-term plan which can span as long as 20 years and needs consistent efforts," said Jin Xiangcan, a leading expert on water environment at the Chinese Research Academy of Environmental Science.

Containing the pollutant discharge is the key, and it needs the support of various government departments, he said.

"The lake-related problems China is facing now happened in the U.K. and the United States several decades ago," said Jeffrey A. Thornton, managing director of Environmental Management Services Limited based in the U.S.."It's good the Chinese government has realized the importance of environment protection amid the rapid economic development", he said.

Raising the awareness of reducing waste discharge in daily life among children and local residents is also a pressing task for the government, he said.

At least 1,500 delegates from about 45 countries are attending the conference, which runs till Thursday under the theme, "For the Rehabilitation of our Lakes: Global Challenges and Chinese Innovations."