Da Nang has proposed to the Prime Minister that the term 'xa lu' (flood discharge) be replaced with 'dieu tiet qua tran xa sau' (deep spillway regulation) in Procedure 1865. The city argues that the current terminology does not accurately reflect technical operations. Mr. Truong Xuan Ty, Deputy Director of the Da Nang Department of Agriculture and Environment, announced this at a press conference on 2/12. The recommendation, sent on 4/11, included a report detailing severe flooding in the downstream Vu Gia - Thu Bon river basin. This region had experienced three inundations in over 5 weeks, with some areas submerged up to 2,5 meters deep, just prior to the report's submission.

Mr. Ty explained that Da Nang's proposal specifically targets articles 28, 30, 31, and 34 of Procedure 1865, which governs the inter-reservoir operation of the Vu Gia - Thu Bon system. He believes that 'deep spillway regulation' more accurately describes how hydropower reservoirs are managed and will bring greater consistency to official administrative documents.

He elaborated on Procedure 1865, which outlines three stages for flood season operations. Stage one involves lowering reservoir water levels in anticipation of heavy rainfall. During stage two, as inflow rapidly increases and downstream levels rise, the reservoir maintains its water level by releasing an equivalent volume. Stage three occurs at the flood peak, where discharge is reduced below the inflow to alleviate downstream pressure.

"All three stages operate through deep spillways, which are designed for flood regulation, thus requiring a consistent term to prevent misinterpretations," Mr. Ty stated.

Mr. Truong Xuan Ty speaks at the press conference. Photo: Nguyen Dong

The Deputy Director highlighted a significant limitation of Da Nang's reservoirs: their limited flood control capacity. During the recent flooding, the A Vuong, Song Bung 4, and Dak Mi 4 reservoirs received nearly 1 billion cubic meters of water, despite a combined maximum flood control capacity of just over 264 million cubic meters. Consequently, the city will advocate for increasing flood control capacity and implementing earlier reservoir water level reductions based on forecasts to improve flood mitigation.

Mr. Ty reported that Da Nang experienced over 2,000 mm of rain during three peak periods in October and November alone, which is nearly the annual average of 2,400 mm. This concentrated rainfall overwhelmed the drainage system, significantly escalating the risk of natural disasters.

To ensure long-term safety, the city plans to develop a project for stabilizing mountain communities. Local authorities will identify suitable locations and engage experts to survey for sustainable resettlement arrangements. The City Party Committee mandates the completion of these tasks by Q1/2026.

Hoi An ancient town, situated along the Hoai River (a branch of the Thu Bon River), experienced prolonged flooding from late October to early November 2025. Photo: Nguyen Dong

Nguyen Dong