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HCM City plans for big floods

Update: June, 25/2009 - 00:00

HCM City plans for big floods


The tradition of using dykes and steel could be unsustainable.

People travel in the floods in Nguyen Huu Canh Street, HCM City’s Binh Thanh District. — VNA/VNS Photo Trang Duong

HCM CITY — Hundreds of experts gathered yesterday in HCM City for the second day of an international workshop on climate change, calling for new strategies to protect Viet Nam’s highly vulnerable southern region.

Speaking at the meeting beginning on Wednesday, Professor Le Huy Ba, the rector of the Institute for Environmental Science, Engineering and Management, said flooding in HCM City was caused partly by a combination of rain, rising tides and urbanisation.

Climate change, however, in recent years was the major cause behind increased flooding, he said.

Ba said the problem was worsened by the fact that residential urban areas and industrial parks had not followed a master plan, which had led to inadquate drainage systems.

Dr Christopher George, executive director of the International Association of Hydraulic Engineering and Research, said the traditional approach of using dykes, concrete and steel could lead to unsustainable solutions.

A new balance between natural, economic and social functions was needed, he added.

"This requires a deep understanding of these functions, and calls for a knowledge-based, integrated approach in information gathering, modelling and decision-making," he said.

"Decision-makers at the government level will need to make informed selections among options which are frequently in conflict and uncertain," he added.

Long-term strategies

Nguyen Kim Dan of the Saint-Venant Laboratory for Hydraulics in France said that to improve flood prevention, HCM City must develop medium- and long-term strategies based on interdisciplinary knowledge about floods, risk assessment and management.

During the last few years, traditional methods of flood protection have been replaced by a new paradigm based on risk management, including risk analysis methodology that takes into account all benefits and costs.

Dan said urban flooding could not be eliminated and a flood-resilient strategy had to be developed to protect vulnerable areas in Viet Nam.

Prof. Hiroaki Furumai of the research center for water environment technology of the graduate school of engineering at the University of Tokyo, said that it was necessary to have a comprehensive control programme for urban flooding inundation.

New criteria should be developed for flood management, including protecting human lives, conserving city functions, and protecting private property.

Furumai said collection of data on drainage systems, land use and rainfall inundation was important for the city to deploy countermeasures like the New Quick Plan for Stormwater Control, Sewerage Mapping and Information System (SEMIS).

An early urban flooding warning system using mobile devices could also spread messages to people.

Publicising an inundation hazard map would be a strong incentive for relevant stakeholders to co-operate and would be useful for citizens to understand the situation, he said.

J P Lobo-Ferreira of the groundwater division of the Portuguese National Laboratory of Civil Engineering said an urban flood control policy should emphasise the use of urban runoff and flood simulation to identify the most hazardous zones.

Dr K M Nabiul Islam, senior research fellow with the Bangladesh Institute of Development Studies, said the most important way of confronting the alarming situation was to obtain a better understanding of climate change and its dynamic, which is linked to water or flood management.

He said it was important to improve the knowledge of how natural hazards magnified by urbanisation and climate change could cause havoc to human life and property.

Coordinated efforts in urban infrastructure development, land-use planning, strong enforcement, participatory investment and a safe water supply, as well as regular and adequate provision of resources at the local level, constituted the major elements of a comprehensive urban flood and climate risk management, Islam said. — VNS


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