The plan was announced at a workshop on urban drainage, flood control and wastewater treatment held by the city's Department of Construction on September 15.
Le Ngoc Linh, deputy director of the department, said that following the administrative merger, the city covers about 6,778 square kilometres and is divided into 23 major drainage basins with varying terrain and hydrological conditions.
HCM City faces growing risks from extreme weather, high tides, sea-level rise and land subsidence, while outdated planning and poorly connected drainage infrastructure hamper flood control.
The expanded city has 159 sites that are regularly flooded, including 76 in the former HCM City, 52 in former Binh Duong Province and 31 in former Ba Ria-Vung Tau Province.
Between 2026 and 2030, the city plans to complete 87 projects costing about VND 140 trillion, aiming to largely address flooding at 50 sites, including 34 in the former HCM City, nine in former Binh Duong and seven in former Ba Ria-Vung Tau.
According to the department, flood control should shift from tackling individual sites to basin-wide management, factoring in extreme rainfall, high tides, sea-level rise and land subsidence.
The city plans to combine conventional drainage infrastructure with green infrastructure, retention lakes, stormwater storage areas and nature-based solutions. Digital data and forecasting and warning technologies will also be used to improve management.
HCM City also aims to collect at least 80 per cent of urban wastewater by 2030 and treat 40-45 per cent to required standards, compared with about 52 per cent and 19.5 per cent, respectively, at present.
Linh added bottlenecks extended beyond treatment plant capacity to poorly connected collection networks, pumping stations, connection points and transmission pipelines.
The city plans to prioritise infrastructure to channel wastewater to treatment plants operating below capacity, while coordinating collection networks with road and alley upgrades, urban renewal and flood-control projects to avoid repeated roadworks.
Consultants warned that without flood-control investment, annual losses could reach USD 150 million by 2100. Coordinated infrastructure projects and nature-based