RAP Publication : 1999/14



Proceedings of the Regional Workshop
Vientiane, LAO PDR
19–21 March 1998

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Excessive flooding is a worldwide problem which in many countries results in loss of life and extensive damage to infrastructure and agricultural production. Much of the international emergency assistance is directed to alleviate the immediate short-term problems arising as a result of excessive floods. However, more lasting solutions are required to overcome and reduce the negative effects of flooding in a sustainable way.

Flooding of the Mekong River and its tributaries is a recurrent event and each year causes damage, in varying degrees, to agricultural production, rural infrastructure and human settlements. Floods reached disastrous proportions in 1995, 1996 and 1997 in Lao People's Democratic Republic, Cambodia, Thailand and Viet Nam with serious losses in food production and human lives.

Following the severe flooding of 1995, the Government of the Lao PDR appealed for international emergency assistance. Under its technical cooperation programme (TCP), FAO provided technical assistance to the Department of Irrigation with the specific objectives of developing a better understanding of the dynamics of the flooding, defining options for flood loss prevention and a strategy for flood management for its vulnerable agricultural sector. The Flood Loss Prevention and Management Plan for the Agriculture Sector project (TCP/LAO/6613) initiated activities in June 1996 that were concluded at the end of 1998.

A range of activities and studies were undertaken under the FAO technical assistance to explore the various options for flood management and mitigation. In order to present its findings and to exchange experiences with others, in particular with those in the Mekong riparian countries, the project undertook the organization of a regional workshop in close cooperation with the Mekong River Commission Secretariat (MRCS).

The Regional Workshop on Flood Management and Mitigation was held from 18 to 21 March 1998 in Vientiane to review the various techniques and approaches to improve the management of floods and local preparedness to mitigate the negative effects. Regional experts and senior officials from the Mekong riparian countries and a core of international specialists and representatives from investment and development agencies in the region exchanged experiences, discussed the various options and prepared specific recommendations that could lead to a better preparedness for flooding and may reduce the negative effects of floods in a sustained manner.

The proceedings of the Workshop are contained in this report and provide a description of the various technical options in flood management as presented in the papers prepared by the regional and international specialists and summarized in the findings and recommendations of the Workshop.

It is hoped that the report provides the national governments and experts dealing with the recurrent problems of flooding in the Mekong riparian countries, and also in other countries in the world, with valid solutions to alleviate this severe problem.


The organization of the Regional Workshop on Flood Management and Mitigation of the Mekong River and its Tributaries has been a joint effort by the Food and Agriculture Organization, the Mekong River Commission Secretariat and the Department of Irrigation of the Ministry of Agriculture and Forestry of the Lao People's Democratic Republic.

The support received from the Director General of the Department of Irrigation, Mr Langsy Sayvisith, and Mr Bouriboun Sunasisane, Acting Director of the Lao National Mekong Committee, in the organization and hosting of the Regional Workshop is gratefully acknowledged. Special appreciation is due to Mr Boonthian Oondara of the Department of Irrigation who, as National Project Director of the FAO TCP project, has played a major role in the achievements of the project and in the organization of the Workshop.

The staff of the Mekong River Commission Secretariat, Mr Sok Saing Im, Chief of the Hydrology Unit, Mr Hideaki Tanaka, Senior Hydrologist of the Hydrology Unit, and Mr Nokeo Ratanavong of the Technical Support Unit have provided valuable assistance in the organization of the Workshop and in the invitation of the regional participants.

The assistance of the FAO representative, Mr P. Hijmans, and his staff has importantly facilitated the local organization and arrangements for the Workshop. The inputs and contributions of the different international and regional specialists and resources persons have provided the core of the valuable experiences and findings compiled in these proceedings. The contributions of FAO colleagues Messrs John Latham and Mike Andjelic and FAO consultants Messrs Adri Verwey and Tim Stephens need special mention.

Considerable efforts have been made by Mr Lance Woodruff in the editing of the report in close cooperation with Mr Klaus Siegert, FAO Regional Water Management Officer in the FAO Regional Office in Bangkok. The editing was completed by Mr Evert de Nooy in Rome. Special appreciation is due to Ms Chrissi Smith-Redfern in FAO Headquarters who completed the formatting and final composition of the report.

The FAO Service for Special Relief Operations (TCOR) has had operational responsibility for the implementation of the project and in particular the support of Mr Werner Chakkalakal in the organization of the Workshop is acknowledged.

The technical supervision for the implementation of the TCP project, the organization of the Workshop and the preparation of this report have been carried out by Mr Martin Smith, Senior Officer in the FAO Water Resources, Development and Management Service.

Food and Agriculture Organization of the United Nations
Mekong River Commission Secretariat
Department of Irrigation, Ministry of Agriculture and Forestry of LAO P.D.R.
Bangkok, March FAO/RAP 1999

Hyperlinks to non-FAO Internet sites do not imply any official endorsement of or responsibility for the opinions, ideas, data or products presented at these locations, or guarantee the validity of the information provided. The sole purpose of links to non-FAO sites is to indicate further information available on related topics.


Summary report and recommendations

Technical session I: Introduction to flood management

Flood forecasting and management in Lao PDR Bouriboun Sanasisane

Options in flood management and mitigation: findings of the FAO TCP project Martin Smith

Review of flooding and flood management in Cambodia: Cambodia country statement Mao Hak and Norng Piseth

Fflooding and flood management in Thailand Varunee Charoensamran

Review of flooding and flood management: Viet Nam country statement Le Thi Tam Thien

Technical session II: Flood surveys, GIS and remote sensing techniques

Flood surveys and mapping of flood-prone areas in Lao PDR Boonthian Oondara

Processing GIS flood mapping data for Lao PDR Victor Gillespie and Sengkham Inthiravongsy

Remote sensing techniques in flood assessment John Latham

Remote sensing for inundation mapping in the Lower Mekong Basin Nokeo Ratanavong

1997 flood vulnerability mapping pilot project in Cambodia Jeffrey Himel

Technical session III: Flood forecasting and river modelling

The Mekong hydrology programme Sok Saing Im

Flood forecasting of the Mekong River in 1997 Hideaki Tanaka

Flood forecasting on the Mekong River in Lao PDR Janice Green

Hydraulic modelling and flood control planning in the Mekong Delta Nguyen Xuan Hien

Flood forecasting and river modelling of the Mekong Basin Adri Verwey

Reservoir management and options for flood control Engelbert Oud and Terence Muir

Water resources and flood monitoring of the Nile RiverBasin M.M. Andjelic

Technical session IV: Flood control works

Proposed pilot project for flood prevention: Pilot project Bolikhamxai Timothy Stephens

Vientiane Plain flood protection: urgent phase R.L. Brown

ANNEX I: Opening addresses


ANNEX III List of participants

Summary report and recommendations


Flooding of the Mekong River and its tributaries are recurrent events and cause each year in varying degrees damage to agricultural production, rural infrastructure and human settlements, which can reach disastrous proportions with serious losses in food production and human lives. The floods occur during the monsoon period from August till November and are caused by heavy tropical storms and typhoons originating in the Chinese Sea.

The 1995 and 1996 floods were exceptionally serious. An analysis of flood levels of the Mekong River over the past thirty five years shows that only in 1961 and 1966 were similar flood levels reached. The floods of recent years show an upward cycle and 1994, 1995 and 1996 flood levels were well above average. Losses in agricultural production were substantial, and particularly exceptional in 1995 and 1996.

In 1994 flooding by the Mekong River in Laos damaged about 28 000 ha of cropped land. The floods of 1995 and 1996 were the worst since 1966, and seriously affected agricultural areas along the Mekong and its tributaries in the Prefecture of Vientiane and the provinces of Vientiane, Bolikhamxai, Khammouane, Savannakhet and Champassak. Up to 87 300 ha were inundated in 1995 and 76 000 ha in 1996. Considerable damage was caused to irrigation and other infrastructure, as well as to about 260 ha of fishponds.

The floods of 1996 caused even greater damage in Cambodia: more than 450 000 ha were affected and flooding in the lower Delta area of Viet Nam caused heavy casualties.

The Laotian Government reacted swiftly to the emergencies arising from the 1995 floods. It requested FAO assistance to address the recurrent flood problem and to define options for flood loss prevention as well as strategy for flood management for its vulnerable agricultural sector. Under the FAO technical cooperation programme (TCP), a technical assistance project was formulated, titled Flood Loss Prevention and Management Plan for the Agriculture Sector (TCP/LAO/6613). The project started activities in June 1996 with specific objectives to develop a better understanding of the dynamic of the flooding and to elaborate on the options to prevent and mitigate the negative effects of recurrent floods.

The project undertook the survey of flood prone areas along the Mekong River and its tributaries and initiated activities to elaborate on the various options to better monitor floods and to define measures to reduce the effects of flood damage.

The regional workshop

The regional workshop was held from 19 to 21 March 1998 in Vientiane to present findings and results of the FAO assisted project on Flood Loss Prevention and Management Plan for the Agriculture Sector (TCP/LAO/6613).

Jointly organized by the Irrigation Department of the Ministry of Agriculture in Laos, FAO, and the Mekong River Commission (MRC) in Bangkok, the workshop provided an opportunity for specialists and senior officials from Laos and riparian countries in the region to exchange experiences and to assess areas for further cooperation and support.


The specific objectives of the Workshop were:


Over 50 participants attended the Workshop, including senior officials and specialists from various departments and ministries in the Lao PDR and representatives of the MRC National Committees and its line agencies in Cambodia, Laos, Thailand and Viet Nam. International resource persons and specialists from regional and international institutes and consultancy firms, as listed in Annex III, presented a total of 21 papers, including country reports, technical background papers and studies, as listed in the Table of Contents.

Representatives of national and regional development and investment agencies attended. including ADB, EU, UNDP, WFP and several NGOs. The FAO was represented by technical specialists from its Headquarters and field projects and by representatives from the FAO country offices in Laos and Cambodia. Three technical specialists from the Secretariat of the Mekong River Commission participated and contributed to the organization of the workshop.

The various issues were discussed and reviewed during the final session of the workshop in three discussion groups in order to reach consensus on common issues and to make recommendations for further follow-up.


The Agenda is attached as Annex II. Five sessions were held in which various aspects of flood management were elaborated:

Summary outcome

The Workshop focused on the importance of reducing the often disastrous effects of recurrent floods of the Mekong and its tributaries. The various options to improve flood management and to achieve better flood control for food security and rural welfare in the region were highlighted in order to achieve more lasting solutions to recurrent flood problems.

Better regional cooperation was needed and national governments required adequate technical support and resources. The role of the MRC Secretariat (MRCS) was considered essential to ensure regional cooperation and to assist national governments in the implementation of national flood management plans. MRCS capacities need to be strengthened in particular to introduce new and technologically advanced techniques in flood monitoring and flood forecasting. Similarly the capacities of the riparian line agencies need to be developed. The necessity for FAO and other development agencies to support national governments and act as partners in regional cooperation to introduce sustainable solutions to overcome flood problems in the agricultural sector was recognized.

A range of interesting technical aspects and issues were addressed which allowed to present in a more systematic way the various options and requirements to overcome the recurrent problems of floods along the Mekong River Basin. These aspects are summarized as follows:

The specific findings and recommendations of the participants, as formulated in the groups meetings during the workshop are presented in the section Conclusions and Recommendations of this report.

Flood Management Options

For sustainable agricultural development of the alluvial plains of the Mekong River, a national strategy and action plan is a prerequisite to achieve a national and regional preparedness for recurrent floods.

The flood events have revealed considerable weaknesses in the way flood calamities are being addressed. Information on the extent of the flood-affected areas and the extent of the damages are still not well known and collected data show conflicting information. The unpreparedness and lack of procedures to assess the extent and damage caused by floods damage has effected the allocation and mobilization of emergency assistance and the readiness of local institutes and agencies to offer effective support.

The experience of the MRCS and the FAO assisted project have been instrumental in developing a better understanding of the dynamics of the floods, in developing procedures to better assess flood behaviour and in defining various answers to prevent and restrict the damage caused by floods. As a result, several short-, medium- and long-term solutions have been recommended to minimize negative impacts of floods and to mitigate damage in a more sustainable way.

Solutions to overcome the effect of floods can be found at different levels and in different sectors, and involves cooperation and coordination at international, national, provincial and field levels. They can be classified as follows:

The various options to manage and regulate more effectively flood waters need to be consolidated in a national flood management and flood mitigation strategy. Such national flood management plans and strategies will include:

Responsibilities at national and local levels for flood management and mitigation need to be entrusted to the National Flood Management Unit, Specific would include defining flood mitigation measures, monitoring annual floods and creation of national and local preparedness for floods, Inter-ministerial capacity to effectively initiate and coordinate and national actions to flood management should be increased.

Conclusions and recommendations

Although the recommendations are applicable in the first instance to conditions in Laos PDR, those relating to national issues are also valid for other riparian countries. The groups' findings and conclusions as presented below:

Flood surveys, GIS and remote sensing techniques



Flood forecasting and river modelling



Flood control works



Local preparedness in flood xontrol



National Flood Management Action Plan