Hanoi: Why Did Quang Trung Street Still Flood Despite the Completed Drainage Project?

On July 10, 2026, the Hanoi Technical Infrastructure Management Center released new drainage data. The center operates under the Hanoi Department of Construction. Specifically, the report addressed a heavy 30-minute downpour on July 9 that triggered localized flooding across several central streets.

The center reported that a low-pressure trough across northern Vietnam brought heavy rain on July 9. Central Hanoi saw widespread rainfall between 40mm and 80mm. Some areas recorded even higher levels. Yen So reached 84.4mm, while Viet Hung saw 73.6mm. Hoang Mai recorded 63.7mm, and Hai Ba Trung hit 52.8mm. Thanh Liet also reached 46.5mm.

The intense, short storm caused immediate flooding at multiple key capital junctions. Floods hit the intersections of Lien Tri–Nguyen Gia Thieu and Quang Trung–Tran Quoc Toan. The waters also stalled traffic at Phan Boi Chau–Ly Thuong Kiet and the Ba Trieu five-way intersection.

Photo: Collected 

When the downpour hit, the center ordered the contractor to open the discharge gate into Bay Mau Lake inside Thong Nhat Park. Opening the gate secures drainage for the surrounding neighborhood. However, this step faced complications because the city is still inspecting and handing over the new infrastructure before its official launch.

“However, workers delayed opening the sluice gate,” stated Mr. Nguyen Duc Hung, Director of the center. “This gate connects the Quang Trung Street drainage axis to the Thong Nhat Park regulating lake. Unfortunately, the delay caused the localized flooding. Workers finally opened the gate, and the water receded completely within 30 minutes.”

Mr. Hung emphasized that the new drainage system usually clears water rapidly. The city controlled all other potential flooding points. He blamed the single failure on yesterday’s delayed manual operation of the Thong Nhat Park sluice gate.

“We held an emergency review meeting on the night of July 9,” Mr. Hung affirmed. “Our team drew lessons regarding system operations. We will ensure this failure does not happen again.”

The anti-flooding project commenced in March 2026. It features 22 separate infrastructure components. The initiative included extensive construction at 16 downtown locations. These include key streets like Ly Thai To, Le Phung Hieu, Le Lai, and Phan Chu Trinh. Work also targeted Ly Thuong Kiet, Trang Tien, Tran Nguyen Han, and Tran Nhan Tong. Finally, crews updated Quang Trung, Quan Su, and Nguyen Trai.

Crews finished all construction after four months of active work. These completed systems now play a vital role. They regulate stormwater during the city’s current rainy season.