As of 2016, Hanoi had completed the drainage projects for the inner city with total investment of VND8 trillion.

To prevent floods in the western part of the capital city, VND7.4 trillion was spent to build Yen Nghia pump station in Ha Dong district. With a capacity of 120 cubic meters per second, the station can pump water from Nhue River’s valley to Day River, thus easing floods in the districts of Ha Dong, Thanh Xuan and Nam Tu Liem.

In recent years, Hanoi has spent more than VND15 trillion on anti-flood solutions and the improvement of reservoirs in inner city districts and the western part. However, streets still turn into ‘rivers’ whenever it rains heavily.

Explaining the floods in Hanoi lately, Phan Hoai Minh, general director the Hanoi Sewerage and Drainage Company, said rainfall exceeded the drainage capacity of the system. The drainage system in the inner city (To Lich River basin) in Hanoi can sustain rainfall of 310mm over 2 days.

Meanwhile, the heavy flooding and slow drainage in the western part of the city (including the districts of Ha Dong, Nam Tu Liem, Thanh Xuan and Hoai Duc) is attributed to the incompletion of the water system to the Yen Nghia pump station.

“The capacity of Yen Nghia Station is very big, which can ensure water drainage for the western part of the city. However, as La Khe Canal, which brings water to Day River has not been completed, Yen Nghia Station cannot operate at full capacity when it rains heavily,” Minh said.

According to the Hanoi Construction Department, only the water drainage system in the basins of To Lich, Lu, Set and Kim Nguu Rivers has been completed with the total area of 77.5 square kilometers (Ba Dinh, Hoan Kiem, Dong Da, Hai Ba Trung, Hoang Mai and Tay Ho districts). 

Meanwhile, the drainage system in the western part of the city (Ha Dong, Nam Tu Liem and Bac Tu Liem) has not been built as planned.

Vu Trong Hong, Former Deputy Minister of Agriculture and Rural Development, said the drainage system in the inner city can respond to rainfall of 100 mm/2 hours. If the rainfall is higher, it would cause flooding.

He said that land has been used mostly to build multi-storey houses and urban areas, while investors have "forgotten" to build reservoirs and sufficient drainage systems.

Quang Phong