The dam of the Son La Hydroelectric Project nears completion. – VNA/VNS Photo Ngoc Ha
HA NOI — Deputy Prime Minister Hoang Trung Hai emphasised the opportunity more than 800 delegates from 90 countries had to ensure water security as well as cope with water deterioration and climate change when he opened the 78th annual meeting of the International Commission for Large Dams in Ha Noi yesterday.
The meeting would also provide the chance to promote the development of technology in dam safety, he said.
"The Viet Nam Government has given much attention to the use of hydroelectricity as a clean and renewable source of energy for the country's soco-economic development," the deputy prime minister told the delegates.
"Numerous hydropower plants had been built or were under construction," he said.
These included Hoa Binh, Yaly and Son La.
The deputy prime minister said the operation of hydropower plants, dams and reservoirs helped to balance and harmonise the use of water for electricity, production and domestic use while providing flood mitigation.
The Government had also given priority to water resources and management and had built thousands of reservoirs dams and irrigation systems as well as a dyke system extending over thousands of kilometres. Indian Council of Power Utilities President C.V.J Varma told the meeting: "Hydropower is the most important and widely-used renewable resources of energy and the construction of dams to provide hydropower and irrigation water and to regulate river flow to prevent floods and droughts is essential."
Global water consumption doubled every 20 years and about 1.8 billion people were expected to live in regions of absolute water scarcity such as North Africa and Middle East by 2025, he said.
"Their futures will depend on prudent development of water resources, including large dams and storage reservoirs."
Viet Nam Deputy Natural Resources and Environment Minister Nguyen Thai Lai told the delegates that heavy dependence on international rivers meant that his country's water-security was questionable.
More than 60 per cent of the total average yearly surface water discharge was generated from outside the country.
"There are also potential water shortages and river basin stress, particularly during the dry season, while underground water sources are poorly assessed and understood and under severe development pressure in some places," he said.
Water resources were among the key natural resources most affected by climate change which also threatened dam safety while Viet Nam was one of five countries most vulnerable to sea-level rise.
"The Mekong and Red river deltas are projected to be the most seriously inundated," he said.
"Assessments show that in a 1 m sea-level rise, Viet Nam would lose 5 per cent of its land and 11 per cent of the country's population would be affected."
To better water resources management, Viet Nam would focus on:
The protection of water sources and quality;
The establishment of approaches to river basins;
The provision of accurate data and information for all water managers;
The provision of basic water services to communities; and
Strengthening international relations in water management.
Viet Nam has hundreds of river systems with a total yearly flow of 843 billion cubic metres and hydropower potential of 85,000 GWh per year.
A range of issues
The two-day meeting of the International Commission for Large Dams will deal with diverse key issues.
These include water-resource planning; flood-and-drought mitigation; dam construction and safety; the optimisation of reservoirs; water utilisation as well as irrigation and drainage. The managing director of the Japan Dam Engineering Centre's Engineering Department, Shigeki Kanou, briefed the meeting about the re-development of the Hongouchi-Teibu dam as part of the Nagasaki emergency flood dam project. The emergency project had been undertaken in response to severe flooding in 1982, he said.
It was intended re-develop water reservoirs on major rivers as multi-purpose dams to control floods.
The reconstruction of the reservoirs focused on increasing the thickness of the existing dam to ensure safety and constructing a new spillway to ensure flood control.
The commission's seismic committee chairman Dr Martin Wield focused on the lessons learned from the earthquake in China's Sichuan Province on May 12, 2008.
"Ground shaking causes vibration in dams; their appurtenance structures and equipment as well as their foundations," he said.
"Mass movements like rock falls cause damage to gates, spillway cracks and retaining walls while overturning transmission and other lines."
Earthquake hazard was multi hazard and dams were not inherently safe against earthquakes so technology for building dams that could safely resist strong ground shaking should be applied, he advised. — VNS