Hanoi moves to build 2 emergency underground tanks to tackle persistent flooding

The tanks are planned for an area in front of Hang Da Market in Hoan Kiem Ward and a vacant site near Cau Duong slope in Phu Dong Commune, the official told Tuoi Tre (Youth) newspaper.

The underground tank near Hang Da Market will have a capacity of about 2,500 cubic meters, while the tank at Cau Duong slope is designed to hold about 1,800 cubic meters, the official said.

Preparatory work is under way, with construction targeted for completion before the 2026 rainy season, he added.

The projects are classified as urgent works aimed at easing chronic flooding in parts of the Vietnamese capital.

Flood mitigation is one of five major challenges identified in Hanoi’s long-term master plan with a 100-year vision approved by the municipal People’s Council, alongside environmental pollution, traffic congestion, urban order, and food safety.

Under the plan, Hanoi aims to expand underground infrastructure, including drainage works integrated with transport systems, pumping stations, and water collection facilities.

The city is also studying large-scale underground rainwater storage combined with transport infrastructure, as well as additional retention lakes in low-lying areas prone to flooding.

In the longer term, the plan envisions construction of a large underground reservoir with a capacity of about 125 million cubic meters in the 2036–45 period to address widespread flooding across the capital.