Viet Nam

Viet Nam: Report on the flood development situation and the implementation of flood and storm preparedness and mitigation activities in 2002

Prepared by: UNDP/MARD - DISASTER MANAGEMENT UNIT, VIE/97/002


As of 19 August 2002

(According to Summing Report, dated 19 August 2002, issued by the Central Committee for Flood and Storm Control, on the Flood Development Situation and Implementation of Flood and Storm Preparedness and Mitigation Activities in 2002)

I. Disaster situation in the whole country

From early this year up to now, the weather in Vietnam has been developing unpredictably. At the beginning of 2002, drought devastated many provinces of the Central Highlands and Central and Southern Vietnam. Whirlwinds occurred in most of the areas in the country. Early heavy rains happened in many provinces in the north. In late May 2002, a large flash flood struck northern mountainous province, especially Tuyen Quang, Bac Can, and Lao Cai Provinces, causing huge losses of people and properties.

In June and July 2002, tough drought occurred in a wide area from Quang Binh to Binh Thuan and the Central Highlands, of which, the most severely affected provinces are Thua Thien Hue, Quang Nam, Quang Ngai, and Binh Dinh Provinces in the Centre of Central Vietnam, and Dac Lac Province in the Central Highlands. This is the second largest drought since the drought in late 1997 and early 1998 in this area.

Since July 2002, the flood water levels in the Mekong River System increased rapidly. However, in late July 2002 and early August 2002, the flood water levels rose slower and remained at the same levels as those in 2001 in the same period. Presently, the flood water level on the Mekong River System are increasing rapidly again. It is predicted that the flood water level on the Tien River at the Tan Chau Gauging Station will be at 3.75 meters (0.50 meter below Alarm Level III) and 3.20 meters (0.30 meter below Alarm Level III) on the Hau River at the Chau Doc Gauging Station.

In late July and early August 2002, due to the effect of tropical depressions, there were medium to heavy rains on a large scale in the Northern Vietnam, causing a large flood on the Red River and Thai Binh River. The highest flood water level on the Red River at the Hanoi Gauging Station reached 11.43 meters (0.07 meter below Alarm Level III). From 10 August to 15 August 2002, there were heavy to very heavy rains on the Da River, causing the second large flood on the Red River System. At 07:00 on 16 August 2002, the flood water level on the Red River at the Hanoi Gauging Station reached 11.43 meters (0.07 meter below Alarm Level III - equal to the peak level of the first flood). It is predicted that the peak flood water level will reach 11.80 meters (0.30 meter above Alarm Level III).

II. Some typical disasters and disaster preparedness and response activities

1. Flash flood in Tuyen Quang, Bac Kan, and Lao Cai Province from 13 to 15 May 2002

1.1 Rain Situation

Mean rainfall from 19:00 on 13 May 2002 to 19:00 on 14 May 2002 at some gauging stations was as follows:

  • Tuyen Quang Province: 190 mm at the Vinh Tuy Gauging Station; 170 mm at the Chiem Hoa Gauging Station; and 262 mm at the Tho Binh Gauging Station

  • Bac Can Province: 192 mm at the Ngan Son Gauging Station; 124.2 mm at the Phu Thong Gauging Station; and 101 mm at the Ba Be Gauging Station

1.2 Flood Situation

Heavy rain caused flash flood in Ba Be and Ngan Son Districts, and inundation in Nam Cuong Commune, Cho Don District

On the Lo River, the peak flood water level at 32.03 meters happened at the Ham Yen Gauging Station; at 39.45 meters at the Chiem Hoa Gauging Station; at 54.78 meters at the Na Hang; and 24.77 meters at Tuyen Quang Town.

1.3 Damage caused by flooding

In Tuyen Quang Province: 36 communes and wards in 06 districts and towns were hit by this flood and rain. Total economic losses in Tuyen Quang Province was at VND 27 billion (equal to US$ 1.80million) with 03 people killed; and in Bac Kan Province was at VND 8.7 billion (equal to US$ 0.58 million) with 01 people killed.

1.4 Disaster preparedness and response

After being informed by the National Center for Hydro-meteorological Forecast, the Standing Office of the Central Committee for Flood and Storm Control rang the Provincial Committee for Flood and Storm Control of Tuyen Quang to warn and give guidelines for response to early flooding, which might reach Alarm Level II at the Tuyen Quang Gauging Station. Official Telegraph No.01 at 11:00 on 14 May 2002 was also sent to provinces on the riverside of the Red River and Thai Binh River to warn them of the flood increase which might affect the on-making works on the rivers.

After flooding, the Standing Office of the Central Committee for Flood and Storm Control appointed 02 delegations to visit affected provinces and worked out rehabilitation measures.

In Tuyen Quang Province:

After receiving forecast on rain and flood, Provincial Party Committee, Provincial People's Committee, and Provincial Committee for Flood and Storm Control of Tuyen Quang worked out plans and measures for preparedness and response to flood and rain.

As of 17 May 2002, transportation in the province was cleared. Flood affected households and victims were provided with relief aids to overcome flood aftermath and stabilize livelihood.

In Bac Kan Province:

Right after flash flood occurred in Ba Be and Cho Don Districts, the Chairman of the Provincial People's Committee, Director of the Provincial Committee for Flood and Storm Control visited the affected localities and monitored the aftermath overcoming activities. As of 17 May 2002, transportation in the province was basically cleared. Flood affected households and victims were provided with relief aids to overcome flood aftermath and stabilize livelihood.

2. Drought situation in the Central Vietnam

According to report of the Department for Water and Hydraulic Structure Management, data on drought in the Central and Central Highlands as of 10 August 2002 are as follows:

2.1. Paddy areas affected by drought and water shortage

a. In Central Vietnam

  • Paddy areas affected by drought: 84,133 ha (25,173 ha increase in comparison with that in late July 2002)

  • Paddy areas heavily affected: 42,533 ha

  • Paddy areas destroyed: 23,475 ha

  • Subsidiary crops dried: 30,939 ha (of which 14,520 ha likely destroyed)

  • Industrial trees and fruit trees areas dried: 32,540 ha (of which 14,828 ha likely destroyed)

b. In the Central Highlands (Gia Lai and Dak Lak Provinces)

  • Paddy areas affected by drought: 13,911 ha (6,394 ha increase in comparison with that in late July 2002)

  • Paddy areas heavily affected: 13,911 ha

  • Paddy areas destroyed: 9,009 ha

  • Subsidiary crops dried: 39,999 ha (of which 24,241 ha likely destroyed)

  • Industrial trees and fruit trees areas dried: 2,485 ha (of which 1,061 ha likely destroyed)

2.2. Shortage of using water

Drought caused using water shortage to 807,354 people in affected provinces, especially in Thua Thien Hue, Danang, Quang Nam, Quang Ngai, Binh Dinh, and Ninh Thuan. In addition to shortage of using water for people, drought also caused environmental hygiene problems, especially in coastal localities.

Besides, in some local areas of Binh Dinh Province, NinhThuan Province, etc., drought caused water shortage to livestock, to electric power plants such as Da Nhim and Vinh Son, and some industrial factories.

3. Flood situation on the Red River system

3.1. The flood occurred in late July and early August:

a. Rain situation:

The tropical depression which directly affected Northern provinces has caused heavy rains on July 29 and 30. Mean rainfalls ranged from 100 to 600 millimeters. Especially, rainfalls measured at some areas specified below stayed at high levels:

  • Sin Ho (Lai Chau): 159.7 mm

  • Lai Chau (Lai Chau): 200 mm

  • Tuan Giao (Lai Chau): 150.3 mm

  • Than Uyen (Lao Cai): 728.7 mm

  • Quynh Nhai (Son La): 208.4 mm

  • Bac Ha (Lao Cai): 150.6 mm

  • Mu Cang Chai (Lao Cai): 245.7 mm

  • Tuyen Quang (Tuyen Quang): 223 mm

  • Son Dong (Bac Giang): 175.6 mm

b. Flood situation:

Prolonged heavy rains on a vast area caused flood on the Red River system and the Thai Binh River system. Followings are the highest flood water levels measured at some gauging stations:

  • The Lo River (Tuyen Quang Gauging Station): 27.02 meters (at 13:00 on August 02) - 1.02 meter above Alarm Level III = 27.00 meters.

  • The Red River (Hanoi Gauging Station): 11.43 meters (at 5:00-7:00 on August 04) - 0.07 meter below Alarm Level III = 11.50 meters.

  • The Cau River (Thai Nguyen Gauging Station): 26.91 meters (at 6:00 on August 01) - equal to Alarm Level III.

  • The Thuong River (Phu Lang Thuong Gauging Station): 6.08 meters (at 17:00 on August 01) - 0.28 meter above Alarm Level III = 5.80 meters.

  • The Luc Nam River (Luc Nam Gauging Station): 6.20 meters (at 23:00 on July 31) - 0.40 meter above Alarm Level III 5.80 meters.

  • The Cau River (Dap Cau Gauging Station): 6.28 meters (at 7:00 on August 03) - 0.48 meter above Alarm Level III 5.80 meters.

  • The Thai Binh River (Pha Lai Gauging Station): 5.82 meters (at 7:00 on August 04) - 0.32 meters above Alarm Level III = 5.50 meters.

c. Water regulation at the Hoa Binh Reservoir:

Heavy rains caused a remarkable increase in the water volume flowing into the Hoa Binh Reservoir. Six bottom spillway gates of the Reservoir have been opened to ensure that its standard operational process is observed. However, the water level remained at a peak of 94.65 meters - 1.65 meters above accepted level.

d. Damage caused by floods and rains:

Heavy rains caused a remarkable increase in the water levels of the Nang River and the Cau River in Bac Can Province and of other rivers in Bac Giang Province. The rain also caused flashfloods in Than Uyen District of Lao Cai Province.

In Thai Nguyen Province, there was a problem in the operation of the Sluice No.10 (at Km 2+200). However, the problem was fixed within two hours.

Floods and rains have caused huge damage in terms of human life, property, crops and transportation and hydraulic structures to the provinces of Bac Kan, Lao Cai, Tuyen Quang, Thai Nguyen, Lai Chau, and Lang Son.

  • Number of people killed: 12 (02 in Bac Can, 06 in Lao Cai, 03 in Tuyen Quang, and 01 in Lai Chau)

  • Number of people missing: 02 (one in Bac Can and the other in Lao Cai)

  • Number of people injured: 19 (01 in Bac Can, 18 in Lao Cai)

  • Number of houses heavily damaged: 57 (51 in Lao Cai)

  • Number of houses submerged: 6369 (100 in Lao Cai, 1560 in Tuyen Quang, 4700 in Thai Nguyen)

  • Areas of rice and vegetable crops submerged: 4104 ha (191 ha in Lao Cai, 605 ha in Bac Can, 1186 ha in Tuyen Quang, 2084 ha in Thai Nguyen)

  • A number of transport and hydraulic structures were damaged.

Estimated economic loss:

  • Bac Can Province: VND 25 billion

  • Lao Cai Province: VND 15 billion

  • Lai Chau Province: VND 2 billion

  • Lang Son Province: VND 320 million

e. Government's instructions for flood prevention and fighting:

The Central Committee for Flood and Storm Control issued Official Telegraph No. 08/CD-PCLBTW at 11:15 on July 30, 2002 to the Ministry of Fisheries, the Ministry of Transport and Communications and People's Committees of coastal provinces from Quang Ninh to Ninh Binh.

The Central Committee for Flood and Storm Control issued Official Telegraph No. 09/CD-PCLBTW at 22:15 on July 30, 2002 and Official Telegraph No. 10/CD-PCLBTW at 16:30 on July 31, 2002 to request that provincial committees for flood and storm control of Bac Can, Lang Son, Thai Nguyen, Bac Ninh, Bac Giang, Hai Duong, Hung Yen, Quang Ninh and Hai Phong immediately carry out plans for flood prevention and fighting based on flood situation on the Thai Binh River system.

The Minister of Agriculture and Rural Development and the Head of the Central Committee for Flood and Storm Control inspected preparation activities for flood prevention and fighting in Hai Duong and Bac Ninh.

The Standing Office of the Central Committee for Flood and Storm Control (the Department for Dyke Management, Flood and Storm Control) dispatched mission teams to provinces that have parts of the Red River and the Thai Binh River dyke systems and mountainous provinces in the North for inspecting the dykes and flood and storm preparedness activities; and issued Official Telegraph No.11/CD-PCLBTW at 9:30 of August 01, 2002 to request that the Hanoi University of Water Resources and the Department for Water and Hydraulic Structures Management send a mission team to check flood preparedness and dyke protection activities in the provinces of Bac Ninh, Bac Giang, Hai Duong, Hung Yen, Thai Binh, and Thai Nguyen.

Provincial committees for flood and storm control revised plans for flood preparedness and dyke protection and mobilized all available forces to follow up these plans and to timely fix any problems incurred by flood and rain.

3.2 Flood occurred from August 9 to August 16:

Low tropical pressure caused medium rains in Northern provinces and heavy rains in mountainous areas in the northwest. Mean rainfall ranged from 150 mm to 300 mm. Some areas suffered from heavy rainfalls include:

  • Sin Ho: 338 m

  • Lai Chau: 476 mm

  • Nam Po: 385 mm

  • Pac Ma: 345 mm

  • Binh Lu: 256 mm

Prolonged heavy rains also caused heavy flood on the Da River. Water volume flowing into the Hoa Binh Reservoir reached a peak of 15,100 m3/s and remained at this height for three days continuously. At 7:00 of August 16, water volume flowing into the Reservoir stayed at 9,300 m3/s. The downstream flood water level of the Red River at Hanoi is increasing. At 7:00 on August 18, the flood water level at the Hanoi Gauging Station was at 11.43 meters (equal to last year's flood peak). It is forecasted that the downstream flood water level of the Red River will continue to increase and likely reach the peak of 11.80 meters on August 18. So far, there have been small floods on the Thao River and the Lo River and no flood on the Thai Binh River system.

At present, there is rain in the upstream of the Da River; tropical depression is developing complicatedly and will likely affect Northern provinces. To ensure that the Hoa Binh Reservoir is operated properly and will be able to reserve a large volume of water when there is flood, its six bottom spillway gates will continue to be opened. At 7:00 on August 16, the upstream water level of the Reservoir stayed at 93.95 meters.

III. Works to be done in the coming time

1. Climatic trends in the coming time

Storm No.3 is causing impacts in the southeast of Hainan Island (China), with wind force of Beaufort Scale 8. By night of 19 and morning of 20 August 2002, the storm will hit the east of the Loi Chau Island (China); then it will weaken and disperse.

In the next three days, due to the influence of the tropical convergence which is moving towards the north together with the circulation of Storm No. 3, there will be thunderstorms and heavy rains in some areas. There will be rain in the central and southern coastal provinces. There will be medium rains and thunderstorm in the Central Highlands.

2. Works to be done in the coming time

Presently, the flood water level in the Red and Thai Binh Rivers are at high levels. The weather situations will continue to develop complexly. Followings are tasks needed to be done in response to flood in the Red and Thai Binh Rivers in the coming time:

a. The operation of the Hoa Binh Reservoir should be comply with designated procedures and ensure absolute safety of the works.

b. Ensure absolute safety of the main dyke systems of provinces, especially dykes in Hanoi and dykes relating to Hanoi's dyke system.

It is necessary to regularly inspect and go on a patrol to discover and promptly resolve incidents, avoiding a small carelessness resulting in big disasters.

3. Regarding to outer dykes, it is necessary to manage, repair, and protect main dyke portions. Local provinces should work out measures to evacuate people and ensure the safety of people and properties. In case of large flood endangering main dyke portions and resulting in sudden dyke breakdown, the Chairman of the Provincial People's Committee should allow water spilling to inside the outer dykes, as stipulated in Decree No. 62/1999/ND-CP dated 31 July 1999 by the Government of Vietnam. Losses of lives should be completely avoided.

4. Agencies and bodies appointed should prepare plans for response to the worst possible situation caused by disasters. Military and police should be considered as key forces in dyke protection, people evacuation, and people security ensured. Search and rescue forces should get ready and measures for flood diversion and retention should be well prepared.

5. Weather forecast agency should closely observe and accurately forecast flood and rain situations and possibilities of Storm No. 3 in the next days to actively and effectively monitor the preparedness and mitigation activities.

6. Members of the Central Committee for Flood and Storm Control should continue to implement mitigation plan at the appointment of the leader of the Committee.