HCMC to expand drainage capacity to mitigate flooding

By Ha An   June 28, 2020 | 11:40 pm PT
HCMC to expand drainage capacity to mitigate flooding
A tidal flood control project in Nha Be District in HCMC. Photo by VnExpress/Trung Nam.
HCMC’s drainage system is expected to expand to nearly 2,100 square kilometers, thrice bigger than originally planned to address the widespread flooding issue in the city.

Renovation of the city’s drainage system by 2030 with the vision to 2050 to address flooding will be expanded to cover 23 districts, except Can Gio. About 20 years ago, the plan focused only on 650 square kilometers, which covers 32 percent of the inner city and surrounding areas.

The new plan aims to renovate and upgrade the drainage system and devises special plans for rainwater drainage. Experts have taken into account population growth, climate change, sea level rise and subsidence – factors not included in the previous plan.

It serves to regulate ground elevation and surface drainage, which includes an upgrade of the city’s reservoir system and prioritizes investment in water drainage and wastewater treatment.

The plan entails studying the impact of neighboring provinces such as Dong Nai, Binh Duong, Tay Ninh, Binh Phuoc, and Long An on HCMC’s drainage infrastructure.

Consultants have surveyed sewers of all kind stretching 835 km and measured the cross-section of rivers and canals. They additionally promoted implementing an hydraulic drainage model and calculated city’s overall sewer capacity.

Phan Thanh Tuan, deputy director of Project Steering Committee 5 under the Management Board of Urban Infrastructure Construction Investment Project, said the project objectives are tied with natural and social issues to avoid rampant concrete construction and narrowing water flow.

However, in order to effectively reduce flooding, the project needs to be 80 to 90 percent complete, to include a management mechanism for rivers, canals and ditches.

The completed drainage proposal will be submitted to Project Steering Committee 5 by September end.

The committee will then consult with different departments, experts and communities before HCMC People's Committee submits the plan to the Ministry of Construction for appraisal and later the prime minister for approval.

According to Dr Ho Long Phi, former head of the Center of Water Management and Climate Change at Vietnam National University in HCMC, the expansion of drainage planning is necessary because the old plan is outdated and the city has been seriously affected by climate change and urbanization.

However, to achieve efficiency, the plan needs to be included in overall urban, transportation and ecosystem planning, he noted.

The expert suggested the city implement a roadmap to solve the flooding problem first and identify which areas need to be addressed first and for how long. The city should also avoid not executing the plan timely and let the city sink, he said.

Phi said authorities need to develop a system of scattered water storage areas in central residential areas as a short-term solution to combat flooding.

New residential areas should have space for water storage and a rainwater drainage system, both of which should be regulated, he stressed.

Last year, Climate Central, a U.S.-based nonprofit news organization that analyzes and reports on climate science, revealed most of southern Vietnam, including Mekong Delta and HCMC, could be flooded by 2050.

A study by Vietnam's Ministry of Natural Resources and Environment in 2016 found sea levels would increase by one meter by 2100, and would potentially flood about 18 percent of HCMC and 39 percent of Mekong Delta.

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