Flood-control will be ambitiously upgraded along South China's Pearl River Valley to protect the country's most populous and prosperous area.

Billions of yuan have been earmarked to ensure the safety of millions of people and key cities and regions including Guangzhou, Hong Kong and Macao.

"The latest plan will double the existing standards of water-control projects including dikes, reservoirs and embankments," Wang Qiusheng, deputy director of the Pearl River Water Resources Commission (PRWRC), told some 100 experts examining the blueprint, which if passed by government stake holders, will be completed by 2020. The criterion is expected to be redoubled to prevent havoc from being caused by the worst deluge in 200 years.

Other cities including Nanning, Wuzhou, Liuzhou and Guangzhou, Foshan, Zhaoqing and Zhongshan will also be given protection.

Severe flooding is an annual threat to the region dubbed China's economic engine.

An integrated system will collectively control a network of dams, slewgates, dikes and other anti-flood measures. Although experts passed the planning in principle, it has to be submitted to the State Council for final approval. The timeline for the start of construction has yet to be revealed.

"Improving flood-control capacities along the Pearl River will enable us to ensure a sustainable development along its valley and delta over future decades," Jing Zhengshu, vice-minister of water resources, said.

However, he admitted "there is a long way to go" before the flood defence becomes a reality.

And he admitted the region's booming economy will remain at the mercy of severe floods in the meantime.

"As the largest river in South China, the water course system has not been rectified completely with all flood-control facilities well renovated and updated," Jing said.

The delta borders Hong Kong and Macao and produces about 60 per cent of the region's total gross domestic product (GDP).

The danger has risen because of shrinking flood plains. Land reclamation of tidal flats is also preventing flood waters from flowing naturally.

"If devastating floods occur, the consequences would be too ghastly to contemplate with the valley's sub-standards water-control projects and aging reservoirs," Jing warned.

Covering six provinces and autonomous region of Yunnan, Guizhou, Guangxi, Guangdong, Hunan and Jiangxi, the river valley has played a key role in pushing forward national economy.

With a population of more than 96 million, the river valley is providing China with 11 per cent of the total GDP and 37 per cent of the total gross export value.

Floods along the Pearl River and its tributaries are the biggest threat and could jeopardize the economy.

In 1994 alone, more than 18 million people were affected by floods which caused more than 28 billion yuan (US$3.4 billion) worth of damage.

Today, 23 million people and 690,000 hectares of cultivated land have been brought into effective protection with more than 12,000 kilometres of sea walls, dikes and hundreds of reservoirs built over the past fifty years.

Editor: Yan