Responding to Storm No. 11: Prioritizing dike safety and safe dam operation

Right after storms No. 9 and No. 10 caused severe impacts in the North and North Central regions, storm No. 11 is likely to make landfall in the northern provinces. Although the wind intensity is not as strong as storm No. 10, storm No. 11 is forecast to cause prolonged heavy rain before, during and after making landfall. This is a "double disaster", "storm on storm, flood on flood", posing urgent requirements for localities and units to respond flexibly, not to be subjective, especially to ensure the safety of dikes and dams.

The construction unit is constructing a foot embankment using loose boulders to create a counter-pressure mechanism to prevent landslides on the banks and sloughs of the Huu Thao River, passing through Tam Nong commune, Phu Tho province. Photo: Dao An/VNA

On October 4, Deputy Prime Minister Tran Hong Ha signed and issued Official Dispatch No. 186/CD-TTg on proactively responding to Storm No. 11; emphasizing that the storm could cause flash floods, landslides in mountainous provinces, midlands of the North and North Central regions, as well as flooding in urban areas and low-lying areas. The Official Dispatch also clearly mentioned the danger to the transportation system, dykes, dams, especially those that were damaged by previous storms and floods that have not been promptly repaired.

According to the assessment of the Director of the National Center for Hydro-Meteorological Forecasting, Mai Van Khiem, from the night of October 5 to the night of October 7, the Northern region and Thanh Hoa will have heavy to very heavy rain, generally 100-180 mm, locally exceeding 300 mm, with an intensity of up to more than 150 mm/3 hours. In addition, from the evening of October 5 to 9, the Northern region and Thanh Hoa are at risk of major floods. This puts extremely high pressure on the dyke system and irrigation reservoirs, forcing management entities to proactively respond.

At the meeting on the afternoon of October 3, Deputy Prime Minister Tran Hong Ha requested localities to mobilize forces to immediately handle weak river and sea dikes and urgently repair damaged areas caused by storm No. 10. This must be done in parallel with preparations for storm No. 11.

Dike safety - focus of response

Deputy Minister of Agriculture and Environment Nguyen Hoang Hiep said: From Quang Ninh to Hue, there are currently 62 vulnerable locations in the dike system. Most sea dikes are designed to withstand storms of level 9-10, while storm No. 11 can reach level 12, gusting to level 15, exceeding the design threshold. After storm No. 10 and the subsequent floods, the dike system has recorded 45 incidents. Although many localities have promptly handled the situation, further reinforcement is still needed to ensure safety under new pressure.

According to Deputy Minister Nguyen Hoang Hiep, the weak dike locations, which have been eroded or damaged, need to be prioritized for handling. For example: section K10-K15 of Ha Nam dike (Quang Ninh); Nam Hai dike and embankment (Hai Phong); Dong Minh dike and embankment, sea dike 6 (Hung Yen); Hai Thinh 3 sea dike (Nam Dinh); Bai Ngang, Quynh Long, Dien Thanh, Long - Thuan dikes (Nghe An)... Localities and management units must be ready with forces, materials, and means according to the "4 on-site" motto to ensure the safety of dike projects under construction and key weak locations.

In addition, localities and units need to immediately deploy forces and equipment to ensure communication to serve smooth command and control before, during and after the storm - paying special attention to mountainous areas where there is a high risk of isolation.

Irrigation reservoirs proactively cut floods and provide early warning

Mr. Phan Tien An, Deputy Head of the Dam and Reservoir Safety Department, Department of Irrigation Works Management and Construction, said that the recent storm No. 10 caused very heavy rain over a large area (from Quang Ngai and beyond), in the context of high water levels in reservoirs in the Northern and North Central regions. As soon as the flood forecast was released, the Department of Irrigation Works Management and Construction promptly advised the Ministry to issue a document directing localities and reservoir management units to deploy response measures. These include: 24/7 on-duty; inspection and assessment of project safety, identification of key areas at risk of incidents; large reservoirs with sluice gates need to adjust water levels according to forecasts to receive floods, ensuring safety of projects and downstream areas. Flood discharge warnings must be implemented seriously and promptly to the people.

Thanks to that, large irrigation reservoirs with sluice gates have proactively participated in effectively reducing floods by hundreds of millions of cubic meters of water for the downstream areas, such as Cua Dat reservoir, which has reduced 145/681 million m3 of total flood volume; Ngan Truoi reservoir 127.34/130.77 million m3; Ta Trach reservoir 116/145 million m3. Thanks to these proactive measures, the reservoirs have not had any safety incidents.

According to the Department of Irrigation Construction and Management, on the morning of October 5, the average water level in irrigation reservoirs in the North reached about 69 - 98% of the design capacity. Two-thirds of the region's large reservoirs, Cam Son (Bac Ninh) and Nui Coc (Thai Nguyen), are operating to discharge water to ensure the safety of the works when receiving floods.

The average capacity of reservoirs in the North Central region is from 76 to 99%. However, there are 3 important reservoirs in the storm-affected area managed by the Ministry of Agriculture and Environment, namely Cua Dat reservoir (Thanh Hoa) and Ta Trach reservoir (Hue city) which are being operated to discharge water to welcome floods. The total remaining capacity for flood storage of the 3 reservoirs (including Ngan Truoi reservoir - Ha Tinh province) is about 1,364 million m3.

According to Mr. Phan Tien An, the water level in the irrigation reservoirs in these areas is currently high. From the initiative in the recent storm No. 10, with storm No. 11, the Department of Irrigation Works Management and Construction has promptly issued a telegram and directed localities and management units to inspect the works and immediately repair the damage caused by storms No. 9 and No. 10.

“The units are actively monitoring the weather and proactively planning reservoir operations. In particular, 35 reservoirs with flood control gates in the affected areas have developed reservoir operations plans, proactively lowering the reservoir water level to receive floods according to the process from 7am on October 4,” said Mr. Phan Tien An.

Deputy Minister Nguyen Hoang Hiep requested that localities and units inspect and review key works, unfinished works, especially small reservoirs that have been filled with water due to heavy rains in the area recently. Reservoir owners and relevant agencies urgently operate water discharge to reserve capacity to receive floods according to regulations, especially reservoirs in the Red River, Ma River, and Ca River basins; organize permanent forces and means to be ready to regulate and ensure safety of works and downstream areas in all situations.

The Ministry of Agriculture and Environment also recommends that people living downstream of reservoirs regularly monitor weather forecasts, rainfall and flood discharge schedules from authorities. Grasping accurate and early information will help people proactively prepare plans to prevent and protect their lives and property in adverse situations caused by storms and floods.

Source: https://baotintuc.vn/van-de-quan-tam/ung-pho-bao-so-11-uu-tien-an-toan-de-dieu-van-hanh-ho-dap-an-toan-20251005113043266.htm