The Phan Thiet - Dau Giay expressway is flooded: Whose responsibility is it?

On January 22nd, the Ministry of Transport announced that it had issued a written response to a petition from voters in Ba Ria - Vung Tau province regarding flooding on the Phan Thiet - Dau Giay expressway.

"The flooding on the Phan Thiet - Dau Giay expressway demonstrates the incompetence of the design consulting company and the design appraisal competence of the appraisal agency and the project investor. Voters request that the authorities clarify who is responsible for the flooding on the Phan Thiet - Dau Giay expressway, which agency is responsible, and how will those responsible be held accountable?", voters reflected.

Regarding the aforementioned voter petition, the Ministry of Transport stated that the Phan Thiet - Dau Giay expressway project, which was assigned to the Thang Long Project Management Board as the investor, has had its main route in operation since May 2023, meeting the travel needs of the people and contributing to the socio-economic development of localities in the region. Since its opening, the expressway has generally met quality standards.

At 4:30 AM on July 29, 2023, heavy and prolonged rainfall in the project area caused localized flooding at the section from Km25+369 to Km25+469. Immediately after receiving the information, the Ministry of Transport issued a document requesting the investor to be present at the site along with the construction and operation units, coordinating with the police and local authorities to regulate traffic flow to National Highway 1A, arranging specialized vehicles to rescue affected vehicles, and guiding and managing traffic to ensure smooth flow. By 6:30 AM the same day, the water had receded and traffic returned to normal.

To determine the causes, responsibilities, and propose solutions objectively, scientifically, and cautiously, the Ministry of Transport assigned specialized agencies to review survey and design documents. On August 2nd and 3rd, 2023, the Ministry of Transport dispatched a working group comprising specialized agencies, consulting units, contractors, and experienced hydrological experts to conduct on-site inspections, assess in detail the topographic and hydrological conditions upstream and downstream of the flooded area, and review survey and design documents.

Based on the investor's report, the results of on-site inspections, reviews, and assessments by experts show that the construction process was carried out by the contractors in accordance with the approved design documents, ensuring quality requirements were met.

Regarding the culvert opening at the flooded location: the design consulting unit conducted a survey of water levels and calculated the culvert opening. A review of the catchment area and input parameters showed that the culvert was designed to meet the drainage requirements of the upstream natural catchment area. At the time of the flooding, although the rainfall had not reached the calculated frequency, the elevation was higher than the historical flood peak, which is an unusual factor that needs to be studied and clarified.

Regarding the cause of flooding: the section of the route is located close to the Phan River, with the Phan River dam upstream, approximately 8.6 km from the flooded area. Downstream of dams in general, after being put into operation, the riverbeds and streams undergo changes, sedimentation, and encroachment of vegetation, increasing roughness and narrowing the flow. This leads to a very complex hydrological regime, causing localized stagnation and raising water levels at the sluice gates, resulting in flooding.

Regarding responsibility: this is a newly constructed road. At the time of the survey, the area through which the route passes was sparsely populated, making hydrological data collection difficult. The consultant did not fully anticipate the narrowing of the downstream channel leading to flooding, so the hydrological calculation documents determined the design elevation based on a 1% frequency at the culvert location without considering the flooding water level. Responsibility lies with the consulting unit, although it was not an intentional error.

The Ministry of Transport has requested the investor to urgently coordinate with the local authorities to clear obstacles in the riverbed from the culvert location towards the downstream of the Phan River bridge to increase drainage capacity and lower the water level on the Phan River, reducing the impact of water surge on the construction area; clarify the responsibilities of the units to handle the matter in accordance with the contract regulations, including the costs of rectification due to the faults of the relevant parties.

Following the directives of the Ministry of Transport, the investor has so far cleared obstacles from the riverbed (without using project funds). Simultaneously, an independent consulting firm is conducting surveys, calculations, and mathematical modeling for the entire area to determine the water level corresponding to the project's design frequency, as a basis for proposing a comprehensive solution (if necessary). After the independent consultant submits its report, the investor will conduct an assessment, review the responsibilities of the relevant individuals and groups, and take appropriate action according to regulations.

Comment (0)