Thu Duc loses $54 mln to floods annually: expert

Nguyen Huy Dung, a senior disaster risk management specialist for the World Bank in Vietnam, speaking at a conference to collect opinions on general planning for Thu Duc, said 31% of its land area floods during rains, and this is expected to rise to 37% by 2050.

Annually the floods cause losses of $54 million – or 13% of its revenues, to put it in perspective — and the figure would rise to $84 million in 2050.

The figure represents only direct damages caused by flooding and does not include damage to infrastructure and impacts on economic activities and people’s livelihoods, he said.

“Normally [such] indirect damages are three or four times the direct losses and hundreds of times in some cases.

“In 2003 New York City had a storm that caused $30 billion in damages and most of it was from the stock market and financial and economic activities.”

Thu Duc City was created in 2020 by merging the former district of the same name with Districts 9 and 2.

Spreading 211 square kilometers and with a population of more than one million, Vietnam’s first “city within a city” is expected to account for 30% of HCMC’s economic output and 7% of the country’s per year.

It is also set to become an “innovative urban area” encompassing the hi-tech park in the erstwhile District 9, the university neighborhood in Thu Duc District and a new urban area and financial center on the Thu Thiem Peninsula in District 2.

But flooding is a worry, causing traffic chaos and misery for the local populace every time it rains heavily or river tides rise.

A foreign man wades through the flood in Thu Duc City’s Thao Dien Ward, one of HCMC’s expat quarters, in May 2022. Photo by VnExpress/Quynh Tran

As for solutions, Dung said Thu Duc is surrounded by the Saigon and Dong Nai rivers and should therefore take full advantage of them for water drainage.

It should slow down the water flow and minimize the flow from the upstream to downstream by increasing water filtration and storage, he said.

Then, the water will not flow downstream all at once which would increase drainage pressure and cause flooding down river, he explained.

He said HCMC does not necessarily have to build a dyke to cover the whole city, but have it partially covered and leave the rest to reduce flooding.

In future the northwestern and southeastern areas would suffer more damage due to flooding, and so it is necessary to tweak construction density through land use plans, he said.

Nguyen Do Dung, director of enCity Urban Solutions, an international consultancy for solving urban problems with offices in Vietnam and Singapore, said Thu Duc should build tidal control corridors with sluices placed at the canal mouths to prevent both flooding and salinity.

Reservoirs are the optimal solution to store runoff when the drainage system could not function due to rising river water levels, he added.

HCMC chairman Vo Van Hoan said local authorities need to ensure that any urban planning for Thu Duc dovetails with the overall plans for HCMC.

It is expected that the general planning project for Thu Duc City will be submitted to the HCMC administration in November and the central government in December.