Responding to Storm No. 9: Controlling water levels at reservoirs, ensuring safety of irrigation works

Photo caption — Xuan Quang sluice (Bac Hung Hai irrigation system). Illustration photo: Vu Sinh/VNA

A representative of the Department of Irrigation Works Management and Construction, Ministry of Agriculture and Rural Development said: In the face of the complicated developments of storm No. 9 (storm RAGASA), especially the risk of widespread heavy rain due to post-storm circulation, the irrigation sector has proactively directed localities and construction units to strengthen the operation of regulation, buffer drainage, and control of water levels at reservoirs, dams, and canals to ensure the safety of the construction system and minimize damage caused by flooding. Up to now, no unsafe incidents have been recorded at irrigation works.

Northern localities have proactively operated 10 stations with 39 pumps; buffer drainage sluices such as Ninh Binh operating 40 sluices, Hung Yen operating 13 sluices... Key irrigation exploitation enterprises such as Bac Hung Hai Irrigation Works Exploitation Company Limited and Bac Nam Ha Company have opened and simultaneously operated many large sluices such as Neo, Ba Thuy, Cau Xe, An Tho, Nhu Trac, Co Dam, Coc Thanh, Song Chanh, Vinh Tri and Kinh Thanh to lower the water level, creating capacity to receive floods.

The Northern region currently has 2,495 irrigation reservoirs, including 327 large reservoirs, 480 medium reservoirs and 1,688 small reservoirs. The water level at the reservoirs is currently at 63 - 97% of the design capacity; in which some provinces have high water storage rates such as Ninh Binh (97%), Quang Ninh (95%), Hanoi (94%), Son La and Lao Cai (both 92%), while Lang Son and Cao Bang recorded lower water storage levels, only reaching about 68%. Some reservoirs are currently conducting controlled spills to ensure the safety of the works and downstream areas such as: Khe Che reservoir (Quang Ninh), Cam Son and Suoi Cay reservoirs (Bac Ninh) and Ban Lai reservoir (Lang Son).

For large reservoirs managed by the Ministry of Agriculture and Environment (3 reservoirs), the water storage level ranges from 71 - 91% and the current water level is below the normal rising water level as well as the water level before the flood in September 2025. For the group of reservoirs directly managed by localities, the current water storage capacity reaches 61 - 101% of the design capacity, of which 2 reservoirs (Pe Luong and Yen Lap) have water levels exceeding the allowable level according to the water level before the flood in September 2025, and are currently required to operate flood discharge and lower the reservoir water level to proactively receive floods according to the operating process.

Currently, the entire Northern region has 137 severely damaged reservoirs, distributed in many localities. In addition, the region is also repairing and upgrading 47 reservoirs and building 5 new reservoirs, requiring investors and construction units to strengthen inspection and supervision of construction safety, especially for underground works, deep works, diversion routes; at the same time, proactively develop plans to evacuate people, machinery and equipment when there is a risk of being affected by floods.

In the North Central region, there are currently 2,323 irrigation reservoirs, including 3 especially important reservoirs, 160 large reservoirs, 404 medium reservoirs and 1,756 small reservoirs. Of these, 51 reservoirs have regulating gates, the rest are free-spill reservoirs.

The water storage situation at the lakes is at an average level, with the current capacity reaching 71 - 88% of the design capacity. Some large lakes are currently releasing floodwater under control, including Cua Dat Lake (Thanh Hoa) and Ta Trach Lake (Thua Thien Hue). Of the three lakes managed by the Ministry of Agriculture and Environment, the current water level at Cua Dat Lake is 95% of the design capacity, Ngan Truoi 47% and Ta Trach 21%, all within the prescribed safety limits.

For 14 lakes managed by the locality, the water storage level ranges from 45 - 97%, of which only Da Han lake exceeds the water level before the flood in September 2025, and is currently required to discharge flood water and lower the lake water level to proactively receive floods according to the operating process. The North Central region also has 132 severely damaged lakes and 65 lakes are being repaired and upgraded.

For reservoirs with serious damage, the Department of Management and Construction of Irrigation Works has directed reservoir management units to arrange permanent forces at the works, continuously monitor to promptly respond when incidents occur, in accordance with the motto "four on-site". For reservoirs that do not ensure safety, it is necessary to consider limiting water storage or not storing water.

Implementing the Prime Minister 's Official Dispatch No. 171/CD-TTg on focusing on implementing response work to storm No. 9, the Department of Irrigation Works Management and Construction has issued an official dispatch requesting localities to urgently inspect and review key irrigation works, paying special attention to reservoirs under construction, underground works, diversion works, and small lakes managed by communes.

Localities need to delineate areas at risk of flooding and organize timely drainage before heavy rains occur. At the same time, the operation of reservoirs must strictly follow approved procedures; for reservoirs with regulating gates, it is necessary to calculate the flow to the reservoir, update flood forecasts, and proactively adjust water levels to ensure both safety of the project and production, and to avoid unexpected flood discharges that affect downstream areas.

“In particular, all exploitation and operation units must seriously carry out early warning work for people in downstream areas before releasing floodwaters, as well as when there is a risk of an incident, to ensure people's lives, property and stabilize their lives,” emphasized a representative of the Department of Irrigation Works Management and Construction.

According to the forecast of the National Center for Hydro-Meteorological Forecasting, from the night of September 24 to September 26, in the Northern region, Thanh Hoa and Nghe An, there will be heavy to very heavy rain, with common rainfall of 100-250mm, locally over 350mm. Heavy rain in the Northern region, Thanh Hoa and Nghe An is likely to last until the end of the night of September 26 with total rainfall from the night of September 24 to the end of the night of September 26 commonly 150-300mm, locally over 450mm.

The Department of Irrigation Construction and Management said that the Department will organize a 24/7 shift to closely monitor weather developments and actual situations to have timely instructions and operations in the operation of irrigation systems to ensure the safety of works and people.