Along with the completed drainage project now in operation, for many years, Hanoi City has invested tens of thousands of billions of VND to construct pumping stations to support drainage efforts. Despite this, the recurring situation of “flooding whenever it rains” continues to be a persistent issue.
Flooding During Rain Showers
From the beginning of the summer season (May) to June 22, there have been 5 rain showers in Hanoi. The rainfall intensity compared to many previous years has been at an average of 50 to 70 mm. However, many streets in Hanoi have been severely flooded, causing several vehicles to stall. The most recent rain on the afternoon of June 20 led to flooding on streets such as Vu Trong Phung, Cu Loc, Thuy Khue, Ton Dan, Duong Dinh Nghe, Tran Binh, Phan Van Truong, Hoa Bang, and others.
In fact, a rain shower on the afternoon of June 12 lasted only about two hours but caused dozens of streets to be deeply flooded, completely paralyzing traffic: Trang Tien, Thai Thinh, Truong Chinh, Huynh Thuc Khang, Nguyen Trai, Pham Hung, among others. Additionally, in Nam Tu Liem District, rainwater flooded many basements of mini-apartment buildings, submerging many residents’ motorcycles parked underground.
Flooding on many streets in Hanoi on May 8, 2023.
Regarding this rain event, Mr. Trinh Hong Son, Deputy Director of the Hanoi Drainage Company, stated that a convective cloud area caused the rain on June 12 in Hanoi, with recorded rainfall ranging from 10 to 71 mm/hour.
Specifically, in Ha Dong District, the rainfall was 71.9 mm, in Thanh Xuan District it was 70.7 mm, and in Nam Tu Liem District, it was 69.9 mm. Discussing the flooding situation, Mr. Son noted that due to the heavy rainfall concentrated in certain urban areas, flooding appeared in locations such as Quan Nhan Street, the underpass of Thang Long Avenue, Nguyen Trai, Trieu Khuc (Alley 97 to Ao Dinh), Bui Xuong Trach, and Vuong Thua Vu.
Reflecting on the five recent rain showers, the leadership of the Hanoi Drainage Company indicated that compared to the same period in 2022 (where rainfall exceeded 150 mm/hour), the rainfall in the early summer months had an average intensity of 30 to 70 mm/hour. However, these rain events still exceeded the design capacity of the drainage system in the city, particularly the rains on May 8, June 12, and June 20.
Is the Drainage Infrastructure “Powerless”?
Rain caused water on Nguyen Trai Street to rise above half the wheel of a motorcycle on June 12, 2023.
Regarding the current drainage system, the leadership of the Hanoi Drainage Company stated that the infrastructure, pipelines, and pumping stations from the Hanoi drainage project have been completed and have a capacity of 310 mm/2 per day (equivalent to rainfall of 50 mm/2 per hour).
However, the company representatives noted that most of the rain events causing flooding in the city recently had rainfall intensities exceeding the design capacity of the project (50 mm). In fact, many rain showers in 2022 had intensities ranging from 100 to 180 mm/hour, tripling the capacity of the city’s drainage system. Since May 2023, there have been 5 rain showers across the city, all exceeding 50 mm/hour, with the rain on June 12 and the evening of June 20 having the highest intensities, ranging from 60 to 70 mm/hour.
From this reality of the drainage infrastructure, Mr. Trinh Ngoc Son, Deputy Director of the Hanoi Drainage Company, stated that for rain showers with rainfall up to 50 mm/hour, the city does not experience flooding; for rain showers with rainfall from 50 to 70 mm/hour, the city will have 11 flooding points, including locations such as Ly Thuong Kiet – Phan Bo Chau, Duong Thanh – Bat Dan (Hoan Kiem), Nguyen Khuyen (Dong Da); Hoa Bang (Cau Giay); Thuy Khue (La Pho slope, Tay Ho); Minh Khai Street (Hai Ba Trung); Thang Long Avenue (Nam Tu Liem)… For rain showers with rainfall over 70 mm/hour, the city experiences 19 flooding points…
Regarding flood prevention solutions in the coming time, Mr. Son mentioned that the company has been and is implementing various solutions. Specifically, for the city center area: the company is conducting renovations and dredging of the drainage systems that have been built, including underground sewers constructed decades ago. Additionally, they are utilizing technology-based monitoring systems to connect data on water levels in the sewer systems and regulation tanks to coordinate with lakes, pumping stations, and irrigation dams for proactive and efficient management during rainfall. For the western and southwestern areas of Hanoi – where flooding persists due to rapid urbanization but infrastructure development has not kept pace, the company must mobilize machinery and personnel to assist with forced pumping for drainage.
For areas that frequently experience flooding, including 11 points that have existed for many years, Mr. Son stated that the unit has coordinated with relevant agencies to implement various renovation measures to reduce flooding. However, the leadership of the Hanoi Drainage Company acknowledges that the measures to reduce flooding are only temporary solutions. To truly address the flooding issues in Hanoi, the Hanoi Drainage Company believes that a systematic planning approach is necessary, which includes the prompt completion of the Yen So Pumping Station and the Lien Lac Pumping Station, as well as effectively implementing supplementary drainage projects in the southern and western areas of the city.
