UD-DUT lecturers and researchers participate in proposing solutions for urban drainage in Da Nang city

On the morning of November 2, 2023, the Urban Committee and People's Council (People's Council) of Da Nang city organized a workshop to identify the causes of flooding and propose solutions for urban drainage in the city. The workshop aimed to find solutions to the problem of flooding in Da Nang urban area in recent times.

Attending the workshop, there were a member of the Standing Committee, Vice Chairman of the City People's Council, Mr. Tran Phuoc Son, representatives of leaders of the City People's Council's Committees, and the Management Board of the city's priority infrastructure investment projects of Da Nang city; Hydrometeorological Station of the Central Central region; Scientists. There were 02 lecturers of Water Resource Faculty of UD-DUT, participating in and had 02 presentations including: Presentation on "Causes of flooding and solutions for urban drainage in Da Nang city" by Assoc. Prof. Dr. To Thuy Nga and the presentation on "The impact of flood flow in river basins on urban drainage in Da Nang city" by Dr. Le Hung.

In his speech at the workshop, Mr. Tran Phuoc Son – a member of the Standing Committee, Vice Chairman of the People's Council of Da Nang City said that in recent years, due to climate change, a number of extreme rains have occurred in the city, causing urban flooding. This problem is caused by objective causes, and some subjective causes. It is urgent to evaluate the causes and current status of the urban drainage system, the operation of lakes and dams, the impact of traffic works... on urban flooding.

Mr. Tran Phuoc Son – a member of the Standing Committee, Vice Chairman of the People's Council of Da Nang City

In particular, it is necessary to evaluate the ability of the urban drainage system that has been invested in for many years to respond to the pace of urbanization, population growth and climate change... From there, we will discuss create short-term and long-term solutions and investments. The City People's Council is eager to listen to the objective and independent suggestions and proposals of experts and scientists so that the City People's Council's Party Committee can report to the City Party Committee, as well as through monitoring and regulation activities. When implementing the budget, the City People's Council has a reasonable balance of resources to invest in urban drainage works to cope with climate change causing extreme rain.

Associate Professor, PhD. To Thuy Nga identified some of the reasons why many roads have been deeply flooded in recent times: extreme rains that exceed the frequency of the drainage system's design appear more frequently. Although Da Nang city has the advantage of being adjacent to the sea and having two large rivers passing through it, it has not taken advantage of this advantage to arrange discharge gates to reduce pressure on major routes and limit detour routes. The construction of highways (such as Da Nang Quang Ngai highway, Hoa Phuoc Hoa Khuong road, ...) has caused the law of flood flow distribution from the upstream of Vu Gia river to the downstream to change, specifically The correlation between water levels at Ai Nghia and Cam Le has changed completely, so the water level at Cam Le depends on coastal rain rather than upstream rain as before.

Assoc. Prof. Dr. To Thuy Nga presented in the workshop

The water level on the Phu Loc River during heavy rains is quite high because a large amount of water flows upstream, making it difficult for the outlets to this river to drain naturally. Another important note is that the flow concentration time and flood peak value depend greatly on the buffer surface. With the rapid pace of urbanization, even the sidewalks are now concreted with no place to absorb rainwater anymore, leading to all the rainwater pouring into the sewers and exceeding their capacity, leading to flooding. Therefore, we need to recalculate the amount of rainwater that needs to be drained according to the actual rainfall for the subdivisions, evaluate the capacity of the sewer lines and propose to expand or create additional sewer lines and outlets to increase the chance of escape. We need to prioritize land funds to arrange flood drainage corridors, form regulating lakes and increase the area of green corridors and urban green areas, minimizing the use of concrete... At the same time, we It is necessary to urgently evaluate the current planning status of the city's foundation elevation and drainage capacity.

Dr. Le Hung suggested that the city should soon complete demarcation of flood drainage corridor boundaries for Da Nang river basins and consider carefully evaluating traffic works that obstruct flood flow. At the same time, more accurately evaluate design projects during the appraisal and verification process of drainage projects. Da Nang needs to expand and arrange more outlets to rivers and seas such as opening locations on Phung Hung, Ho Quy Ly Ly Thai Tong, and Ha Khe locations to Nguyen Tat Thanh sea. This is the basis for reducing the water level on the Phu Loc River and increasing the drainage capacity of the sewer lines as well as increasing the flood drainage capacity through the Da Co Bridge area as a basis for proposing drainage solutions in the area Me Suot.

Dr. Le Hung

Similarly, Da Nang needs to open the discharge gate from Tran Thi Ly to Asia Park. This will be the basis for good drainage for the area, as well as dividing drainage basins for the 2/9 monument area, Nui Thanh street, 30/4 street, Le Thanh Nghi and Phan Dang Luu... Although the upstream sewer system has the ability to drain, it stagnates at the outlets leading to flooding such as at the intake gates of Ong Ich Khiem pumping station, Thuan Phuoc pumping station..., the city needs to consider assessing the flow of water. discharge volume of pumping stations. In addition, it is necessary to re-evaluate the effectiveness of pumping stations in response to the current period, including adjusting the self-flowing ability of Truong Chi Cuong pumping station because the river water level is now lower than the river water level in 2012. This occurred due to the impact of traffic projects and hydroelectric reservoir systems causing the river water level to decrease.

At the same time, the city needs to soon build an urban flood map corresponding to 3-5 rain levels, and a map of travel directions to avoid flooded spots. Then, based on the forecast rainfall conditions, the city will use it as a basis for response.

The workshop also received many comments from experts and planners in Da Nang city. In addition, delegates attending the workshop also proposed that the city need to strengthen communication and education, propagandize people not to block water pipes to obstruct the flow, and join hands with the government in the work of opening the flow of water. flows when heavy rain occurs. The city needs to strictly control construction activities in the area and strictly handle cases of dumping construction waste into the drainage system. In addition, the city needs to dredge intake gates and sewers associated with community monitoring, ensuring the drainage system is smooth to maximize existing capacity.

Head of the Urban Department, City People's Council, Mr. Nguyen Thanh Tien highly appreciated the comments and suggestions of experts and scientists. The Board receives and reports and proposes to the city urban drainage solutions in the short, medium and long term.

Head of the Urban Department, City People's Council, Mr. Nguyen Thanh Tien

Hopefully, through the report content of experts from UD-DUT, it will help strategic planners of Da Nang city have a more general view. And the City will find a practical solution to solve the recent flooding situation in Da Nang.

News: Learning Resources and Communication Center