Since the center of Da Nang has been hit by massive flooding for two years in a row, Dr. Le Hung from the Da Nang University of Science and Technology has said the coastal city needs to seriously consider its approach to planning and developing a drainage system to prevent the situation from worsening.

Six periods of unusual rainfall have been recorded in the central region of Vietnam in the last ten years, Dr. Hung said, citing statistical data from 1979 to 2022.

The increased average rainfall is causing local floodplains to spread. The most severe flood was the historic inundation on October 14, 2022 in Da Nang.

Natural crises in recent years have shown that the drainage systems in both Da Nang and other central coastal cities cannot meet the demands of the current situation, even if the tide recedes.

Dr. Hung believes that cities need to pay attention to various factors to avoid being affected by flooding.

In general, it is important to expand the channels of drainage systems that are directly connected to estuaries.

These systems must be connected directly and in a way that prevents water immediately flowing to the surface.

Hung also pointed out that city officials should thoroughly consider drainage system issues when building roads to reduce the risk of upstream flooding.

“Officials in charge of water supply and drainage systems, infrastructure, municipalities, construction, bridges, roads, and natural disaster prevention must have knowledge of hydrology and hydraulic systems,” Hung said.

“This is the basis for solving drainage problems in cities.

"Therefore, the authorities in charge of this sphere must have officials who, with their in-depth expertise, can make important decisions with a significant impact on the community."

A look at the flood map of Da Nang shows that most of the inundated areas are in the low-lying regions with inadequate drainage systems.

In order to contain such floods, Da Nang needs to expand its rivers and build more sluices, for instance on Ha Khe Street leading to the sea or at Tran Thi Ly Bridge linking to Asia Park.

It is necessary to divide drainage according to catchment areas.

This is because the current drainage system, which directs rainwater from Le Thanh Nghi, Nguyen Huu Tho, and April 30 Streets to Do Xu Canal before flowing into the local Cam Le River, is too far.

The way water is diverted from lower-lying areas to higher-lying areas is inadequate.

Also, the drainage system connected to Phu Loc River would become better with separate areas for drainage, wastewater, and storm water, according to the expert, as the inclusion of such storm water may limit drainage capability.

The floodgates should be restructured to avoid bottlenecks.

Although the upstream sewage system is good enough, the stagnant conditions cause flooding at the gates of the pumping stations of Ong Ich Khiem and Thuan Phuoc.

Due to these conditions, the pumping stations cannot work fully as the water volumes are not sufficient.

In order to fully control flooding in Da Nang, drainage systems and technical infrastructure need to be thoroughly reviewed.

Local authorities must consider the existing plans for the drainage system and for protection against flooding.

Apart from identifying the number of flooding points after rainfall, they should also consider the extent of the inundation at each point and the capacity to handle the flooding in the areas.

The municipality should phase investments in infrastructure to improve adaptive capacity to natural crises.

Last but not least, it also needs such measures as more warnings about natural disasters and ones about potential flooding areas so that residents can plan accordingly.

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