Article 1: The worry of flood during the rainy season

Like many other cities in the whole country, for many years, Vung Tau City has still faced the flood situation on many urban streets whenever there was any heavy and lasting rain.

Construction of the drainage system on Hoang Hoa Tham street, Vung Tau City

There are still 30 locations with a risk of flooding

Although the rain at the end of last April was really heavy, there was little stagnant water on the streets in Vung Tau City. In the “touchy” areas where there was often flood for last years such as the cross-road of Le Loi – Le Hong Phong; the streets of Vi Ba, Le Loi, Nguyen Du; Le Lai – Thong Nhat intersection, this flood situation decreased remarkably.

According to Mr. Hoang Duc Thao – General Director of Ba Ria – Vung Tau Urban Sewerage and Development Company (Busadco), if the rain has an intensity below 50 mm and lasts from 2 to 3 hours, basically there will not be any flood in the province. However if the intensity of rain is higher, from 50mm, 100mm to 200mm and the rain lasts from 4 to 6 hours, there are still 30 locations with a risk of flooding in Vung Tau City. In which, there are “the most touchy” areas such as the T-junction of Le Loi and Le Hong Phong streets; alley 1216 and 1334 of 30/4 street, the section on 30/4 street from Le Quang Dinh street to Nguyen Huu Canh street; the section on Hoang Hoa Tham street from Xo Viet Nghe Tinh street to Ngoc Thuy restaurant; the T-junction of Tran Binh Trong and Binh Gia streets; in front of the office of People’s Committee of Ward 10 and Quarter 2 from the alley 710 to 780 of Binh Gia street; the T-junction of Nguyen Huu Canh and 30/4 streets; Nguyen Thien Thuat street; Ngo Quyen street; alley 484/22 of 30/4 street; Luu Chi hieu street; alley 239 of Le Hong Phong stree; alley 249 of Binh Gia street; the section on 3/2 street from Nguyen Anh Ninh intersection/crossing to Chi Linh tourist area; the cross - road of Le Hong Phong, Ba Cu and Truong Cong Dinh streets….

Garbage is full in the area of Vo Thi Sau lake (ward 2, Vung Tau City) causes obstructs the flow that affects the drainage.

The flood situation still occurs due to many reasons. In which, the main reason is that the lakes in Vung Tau City with the important role in drainage and equalization of wastewater and rain-water have been encroached on gradually and insanitary because many people throw rubbish so uncontrollably that the channel flow is narrowed. Typically, Vo Thi Sau lake (located at the foot of Small Mountain, along Phan Chu Trinh street) with the area of 2.4ha, the depth of 2m ha with the function of regulating the rainwater and domestic wastewater has been narrowed gradually due to the surrounding households’ encroachment. The fish screens of fish farmers affect the landscape. Their stop of water with bags obstructs the flow, decreases the self cleaning capacity of the lake and causes the alarming pollution. Bau Sen lake is located along the streets of Vo Thi Sau and Xo Viet Nghe Tinh is also in the same situation. This lake has a quite large area of 26 ha and receives most of rainwater and wastewater from the South of Vung Tau Airport. The outfalls of the common drainage system in the South of Vung Tau Airport concentrate in this lake. Currently, its embankment has been renovated and the channel flow has been dredged. However the end of lake (the output of the open trench) has been separated by the partition for fish farming and water hyacinths that obstructs the flow.

In addition, on some streets in Vung Tau City, drainage systems have not been invested yet or the sewers are small and overloaded; many streets are downgraded and damaged, the inlets are few and many manholes are encroached that also affect the drainage.

Obsession of drainage

For the mentioned places with many risks of flood when the rain is heavy and lasts, the residents are worried about the lasting flood situation especially when the rainy season is coming. "In recent 3 years, the section of Do Luong street crossing my house and extending to the house No. 121 Do Luong is often flooded every heavy rain" said Mr. Phan Xuan Ngu, 78 Do Luong, Ward 11, Vung Tau City.

According to Mr. Pham Trung Doan, a technical staff of Busadco: a drainage system of Ø600 on Do Luong street for a long time (the section from 30/4 street to the house No. 78 Do Luong) has been invested quite long time ago, but it has not been connected to the common drainage system of Vung Tau City yet, the wastewater was only overflowed into the residents’ farmlands. However, the residents have leveled the ground that has stopped the flow as far as the domestic wastewater flowing into this sewer system cannot be discharged, so that it overflowed to the road and this is the reason for environmental pollution for people living on this street.

Dredging and clearing the flow at the section in front of the house No. 78 of Do Luong street, ward 11

For solving the drainage and preventing the environmental pollution for the area of Do Luong street (the section from 30/4 street to the house No. 78 Do Luong), Busadco dredged and temporarily cleared a sewer along the house No. 78A Do Luong into Dong Sat 1 channel. At the same time, Busadco recommended the People’s Committee of Vung Tau City to agree/approve the People’s Committee of ward 11 to invest in the construction of an additional pipeline of Ø600 with the length of 120m in order to connect the existing drainage system to the general drainage channel of Vung Tau City.

For the area in front of the People's Committee of ward 10 and quarter 2 (from the alley 710 to 780 of Binh Gia street), due to being in a sunken location without any drainage systems, a small rain is also enough to make this section over 200m be into "river". In the area of Xo Viet Nghe Tinh street, there was a drainage system of Ø600 on its left section from Hoang Hoa Tham street to Le Hong Phong street. However, there has not been any drainage system on its right section from Hoang Hoa Tham street to the alley 100. For the sections where a drainage system has not been invested, the wastewater from households along the street has not been collected into the general drainage system of the whole city; they have only used self penetrated tanks; when it rains, the rainwater overflows on the road surface and stagnates along the sidewalk that causes the local flood at the T-junction of Xo Viet Nghe Tinh and Hoang Hoa Tham streets.

(to be continued)

Under the provision of the Ministry of Construction, a local flood place within the allowed limit is the maximum flood depth of 30 cm, the time of flood does not exceed 30 minutes. If the height of flood is from 20 to 30cm within the time of below or equal to 30 minutes, it will be not called a flood but slow drainage. If the height of flood is higher than 30cm within the time of below or equal to 30 minutes, it will be called an untimely drainage. If the height of flood is higher than 30 cm within the time over 30 minutes, it will be called a flood. The calculation of flood time will be begun after 30 minutes.