RAP Publication : 1999/14
FLOOD MANAGEMENT AND MITIGATION IN THE MEKONG RIVER BASIN
|Proceedings of the Regional Workshop|
|Vientiane, LAO PDR|
19–21 March 1998
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 II Agenda
ANNEX III List of participants
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:
to present and discuss findings of the FAO project on flood loss prevention and management;
to develop appropriate recommendations for a national action plan on flood management and flood mitigation in Laos;
to present regional and international experiences in flood management and river modelling: and
to develop recommendations to strengthen regional cooperation in the monitoring and flood management of the Mekong River basin.
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:
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 need to identify, classify and map those areas subject to flooding as the basis for flood preparedness and management;
the potential offered by remotely sensed radar photos to monitor and identify rapidly inundated areas, overcoming problems of overcast skies during flood periods;
the use of GIS techniques to make inventories and analyse in an more systematic manner the impact of floods on agriculture and on infrastructure;
the urgent need to update present MRCSs capabilities in flood forecasting and river modelling;
the need to incorporate flood management as an integrated element in reservoir operation for hydropower;
the considerable potential of flood control works to offer more lasting solutions in flood management;
the need to create a greater local awareness and preparedness in flood relief, flood mitigation and flood management;
the potential for promoting dry season irrigation to offset yield reductions due to flooding; and
the need for a proper institutional capacity at central and decentralized level to address flood problems on a continuous basis;
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:
Flood Surveys and Monitoring of Flood Prone Areas
To put in place an effective flood management and flood mitigation plan, a good knowledge and identification is required of the areas subject to frequent or less frequent flooding and a classification according to depth and frequency of flooding is required to achieve a better understanding of flood behaviour. Furthermore, to be able to react swiftly to areas flooded or threatened by flooding, a monitoring system to assess on a continuous basis the areas each year affected by floods and to have in place emergency measures to reduce and overcome the damage of exceptional floods.
Regional Flood Monitoring and Flood Forecasting
The size of the Mekong Basin makes international cooperation imperative and any flood monitoring and forecasting need to be made in close cooperation with the four member countries of the Mekong River Commission and in consultation also with the two countries sharing the upstream Mekong Basin. The flood forecasting service operated by the Mekong River Commission since the seventies and based on a model developed by the US Army Corps of Engineers is still functional but requires urgent updating using modern concepts of hydrodynamics and river modelling.
The various storage reservoirs established or planned in the country for hydropower development will provide valid options to reduce the high discharges caused by excessive rainfall of short duration. Storage for floods will reduce the capacity for power generation and income. An optimization of hydropower generation and flood absorption through reservoir management modelling is therefore required based on economic criteria.
Flood Control Works and Investments
More lasting solutions to floods will be achieved in the construction of flood control works such as flood gates and protection dikes. Considerable investments are required however to provide more durable protection of agricultural lands and infrastructure. In addition to local investment studies, an overall study and flood management plan will be required to assess the effects and effectiveness of flood investment works and to provide a basis for identifying and prioritizing essential investments for the rehabilitation and construction of flood control and water management infrastructure.
Local Awareness and Preparedness in Flood control
At district and village level, communities should be encouraged to co-operate in the implementation of self-help flood control projects making use of the considerable local knowledge and traditional technologies to find cost effective and sustainable flood control works.
Furthermore, to compensate for recurrent losses due to floods, farmers need to be encouraged to diversify agricultural production and to extend their production basis to irrigated crops during the dry season.
National Flood Management Strategy and Capacity
To deal effectively with recurrent floods and flood emergencies, an appropriate mechanism and capacity needs to be established which will put in place at national and district level adequate measures to cope with flood emergencies and to plan for long-term solutions to reduce and mitigate recurrent flood damages.
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:
an assessment and classification of areas effected by regular flooding,
a monitoring system to assess on a continuous basis the areas each year effected by floods
an overall flood control management plan to manage recurrent and exceptional floods and to have in place emergency measures to reduce and overcome the damage of exceptional floods.
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
Spatial information relating to the physical flood parameters of all phases of the flood cycle and the resulting impact on people, infrastructure, and the surrounding environment, is critical to planning and action preparedness. The inventory of the inundated areas in Laos undertaken by the Department of Irrigation (DOI) and FAO provides an essential information base to better understand the dynamics of floods and to allow the development of flood management action plans. The inventory was carried out through ground surveys using existing topographic base mapping of the areas concerned at 1:50 000 scale.
Subsequent field data collection results were digitized and entered into a newly procured ARCVIEW 3.0 Geographical Information System (GIS) facility with training provided to national staff in its operation. The desktop mapping package allowed the capture and analysis of natural hazard information. The data collected on the surface area inundated and the records of depth, obtained from field interviews, was further processed in inundation maps with relevant statistics and integrated into the GIS package, including 3D models generated from topographic data.
Concurrently with the flood mapping an initiative was undertaken to test the use of RADARSAT data for a more accurate delineation of the inundated area. Although results were not conclusive due to abnormalities with the data acquisition mode of the satellite, the experiences from Cambodia and Laos (WFP/Aruna Tech and MRC/JIID) with inundation mapping using RADARSAT images were presented in the Workshop. The results of these first tests in the region and experiences elsewhere, i.e. Canada, Eastern Europe and Somalia have indicated that Radarsat has considerable utility for mapping of flood inundation. Critical to the optimum utilization of this approach is the knowledge of the appropriate timing of the on set of the flood.
Despite efforts to collect relevant data on the depth of flooding, the information has proved inadequate for the purpose of a flood monitoring system or for the design of flood control measures/structures. There is a need therefore to review, evaluate and make recommendations on the appropriate cost effective procedures which should be followed for the collection of these hypsographic data.
Geospatial data collection and management tools have become commonplace in the Mekong Basin over the last few years in many organizations at the national as well as the regional level. Tools such as GIS, Global Positioning Systems (GPS), map digitizing and scanning equipment, image processing systems, etc., have provided governments and private sector organizations which utilize them, the ability to produce and manage their own “geospatial” information. This capability is dramatically changing the environment within which conventional mapping agencies and those responsible for coordinating data on the environment, operate. This data proliferation has heralded a new era and a plethora of digital data are entering the market, the quality of which in some cases is uncertain.
The concept of a Regional Spatial Data Infrastructure is well recognized in the Mekong region. and in order to achieve a comprehensive and coordinated environment for the production, management, dissemination and use of geospatial data, the MRC has already established a basin-wide coverage of GIS information to which the geospational information base is linked.
Noting the considerable efforts made in the collection of flood information from ground surveys initiated by the DOI and the significant work involved in the processing, collation and presentation of the GIS thematic maps, an integrated approach should be adopted which should be based on ground and satellite based technologies for mapping and analysis of inundated areas. The existing ground data collection will be integrated in the remote sensing studies and allow the calibration and validation of the remote sensed radar data.
To achieve a more precise and comprehensive appreciation and measurement of the ground topography in the data collection, alternative procedures using remote sensing technologies should be evaluated and assessed on their relative cost effectiveness. The use of remote sensing technologies should incorporate the hydrometric network and integrate the hydrodynamic studies. The results of pilot studies, such as initiated in Cambodia by Aruna Technology, should be reviewed and considered in national programmes as they become available.
Stressing the need for coordinating, sharing and disseminating of information related to flood monitoring, a review of the results in the various pilot projects should be carried out and a common approach and joint plan of action defined for monitoring of flooding using radarsat imaginary.
In view of the need for timeliness in flood early warning systems, the information flow needs to be coordinated and information regarding onset and peak of flood likewise needs to be improved. Adequate operational procedures should be put in place well in advance to acquire the requisite satellite data from Radarsat. Appropriate mechanisms for data processing and dissemination of derivative products of relevant flood information data need to be further developed and strengthened.
The installation of a primary data user facility for real time reception of Geostationary Meteorological Satellite (GMS) data is advocated at the regional level with an appropriate dissemination policy for information at the national level.
National capacities for the processing and use of relevant flood data need to be developed and strengthened as optimum use need to be made of national institutes wherever possible. A human resource component at national level needs to be established.
Noting the limited capacities in the region and individual countries and the efforts required to establish at national level specialized capacities in the processing and analysing complex technical data, emphasis is placed on the need for further regional cooperation which will integrate the experience of existing public, international and private sector expertise orientated towards enhanced national capacity building. The MRC Technical Support Unit, presently serving as the regional centre of GIS/RS information, should take the lead in such efforts in close cooperation with the national line agencies in the riparian countries.
International agencies and donors in sponsoring innovative technologies and action plans for flood management remain essential to sustain regional initiatives and cooperation.
Flood forecasting and river modelling
With reference to the significant damage and losses caused by recurrent floods, considerable scope exists to reduce such losses by better knowledge of dynamics of floods
Regarding the considerable progress made in modelling river and flood dynamics and the continued use of the now outdated techniques for flood forecasting by the MRCS, there is a strong need for the introduction of advanced hydrodynamic simulation techniques to achieve improved flood level forecasts in the Mekong Basin, including flood prone subcatchments and the low lying areas of Cambodia and Viet Nam.
Recognizing the important role of the MRCS in flood forecasting information in cooperation with line agencies in the riparian countries, there is a need for an improved system of collection and dissemination of information transfer between the MRCS and the MRC member countries and an appropriate mechanism to disseminate relevant flood warning information within the MRC member countries in a format understandable to the various users and linked to different levels of emergency actions.
To further improve the flood forecasting information and to facilitate the introduction of new technologies, a reinforcement of the hydrometeorological network was considered essential. This is equally valid for the use of emerging technologies which would reduce dependence on ground station information.
The present topographical data base was considered of insufficient accuracy to plan and design flood control and water resources development projects or to utilize in flood and inundation forecasting in the flat flood plains;
Noting the important potential and availability of new and emerging technologies, the use of satellite flood imagery, Differential Global Positioning System (DGPS), topographic mapping, and hydrodynamic modelling were considered necessary and complementary elements in the process of arriving at a detailed insight into flows - backward and forward - in large and flat flood prone areas, such as the Tonle Sap region.
The regional approach to the planning and design support in the water sector as established currently through MRC is a valuable and necessary arrangement that requires further institutional strengthening. Valuable elements are the riparian-on-stipend programmes and on-the-job training.
The staff capacity in Laos and other riparian countries, currently is insufficient to deal effectively with support to the water sector and the complementary role of MRC is recognized as highly opportune and essential.
The present flood forecasting system used by MRCS is recommended to be modernized and upgraded and to include new components such as: pattern recognition techniques to process rainfall forecasts, distributed hydrological modelling, hydrodynamic channel flow modelling and improved updating techniques.
A further extension of the flood forecasting system is proposed to include the Great Lake area of Cambodia (Tonle Sap) and the Mekong Delta in Viet Nam.
The exchange of information and real time data transfer between Regional and National Centres is to be critically reviewed and improved by more reliable communication facilities.
The Centres are to be reinforced through increase of the staff with special emphasis of the further extension of riparian on-stipend positions and on-the-job training assignments.
The Centres need to receive support in the introduction of a consistent and harmonized line of software supporting data base management, simulation modelling and water resources planning.
In relation to the specific findings in Laos it is recommended that:
A more thorough study of the flood phenomena on the Vientiane Plain be initiated, including improved topographic mapping, flood hydrodynamic modelling, damage modelling and reservoir operation optimization.
The reservoirs built in the country should be operated on a multi-purpose basis to serve not only the hydropower production, but also to reduce flood damage and supply irrigation water. New and existing reservoirs for hydropower generation need to carry out studies using appropriate modelling and stochastic concepts for that purpose, to assess their possible contribution to flood damage minimization and the impact on possible reductions in income from hydropower.
The development of flood protection schemes need to be based upon thorough topographic mapping and time dependent hydrologic simulation.
The potential of modern Differential GPS methods be investigated as a means to arrive at improved topographic mapping.
The capacity of national institutes and capability of the supporting staff in the water sector be built up through appropriate institutional support, including riparian on-stipend programmes and on-the-job training.
Flood control works
The Workshop noted the important potential of flood control works to reduce the destructive effects of floods in order to achieve more permanent solutions to protect effectively urban settlements and agricultural lands against recurrent floods. The flood control works considered may include:
diversion channels and retention ponds or retarding basins to divert floods to predesigned wetland areas where habitation and agricultural activities are avoided.
Following the pilot studies undertaken by the FAO project and the flood protection works in the Vientiane plain, it was recognized that the potential benefits of flood protection works in terms of increased crop production would be substantial because of prevention of damage and crop failure, protection of rural infrastructure, as well as water retention for dry season irrigation.
In view of the important ecological function of the wetlands in the flood plains of the Mekong Basin the possible negative environmental impact deserves adequate attention and studies.
In view of the considerable benefits expected from flood control works, the findings of the pilot studies should be used in further studies be undertaken to assess the potential and feasibility of flood protection works. These should take into account the increased agricultural production from flood protection and irrigation, the protection of human lives and rural infrastructure and the possible impact on the environment.
Taking note of the need of an accurate topographical database at scale 1:30 000 and contour lines at 0.50 m, further pilot studies are recommended to assess the use of DGPS systems, as bases for flood protection studies.
Recognizing the need to strengthen local capacities in planning and implementation of flood protection works, training of national and local staff in provinces and districts is recommended. Training would cover preparation of proposals and feasibility studies for flood control works and provision of support to local communities.
In the framework of developing a national policy in integrated water development. adequate attention needs to be given to the preparation of the National Water Sector Profile, including the important potential of flood control works, in order to ensure adequate investment and resources in this sector.
Local preparedness in flood xontrol
Little coordination presently exists among different agencies in the various stages of relief, preparedness, mitigation, and prevention plans to address and mitigate flood disasters.
No well defined procedures are in place at national and local level to disseminate relevant information on imminent floods and to implement appropriate measures to address and mitigate the effects of floods. There is an urgent need for measures to increase emergency preparedness at national, provincial and district level.
Considerable traditional knowledge exists in local communities dealing with recurrent floods. The implementation of flood protection works by these communities can be highly cost-effective and provide better guarantees for sustainability as they can contribute substantially to the costs of construction and maintenance.
Irrigation during the dry season provides an attractive means to overcome the adverse effects of both floods and droughts and could be attractively promoted through community development for flood protection works.
Local awareness and preparedness for flood protection need to be developed in close cooperation with local communities. In each regularly flooded district an inventory should be made of this local knowledge during which communities should be stimulated to propose their own solutions.
Planning of community involvement in flood protection works should be carried out in a participatory manner through a process of consultations and community development. This would increase local awareness and motivation to participate.
Adequate technical and financial support needs to be provided to assist rural communities in the construction of flood protection works.
To provide effective technical support to local communities training of provincial and district staff should be intensified.
Simple low-cost irrigation technologies should be introduced, including small pump fting water from perennial streams, seasonal ponds and water-filled depressions. This intervention would also include developing and improving traditional open wells and improving simple bore-hole drilling techniques.
National Flood Management Action Plan
To promote in a systematic way appropriate actions for flood relief, local preparedness and actions in flood management and flood mitigation, the formulation of a national Flood Management Plan is essential and most appropriate in flood monitoring, flood forecasting, reservoir management, investments flood control works, and local preparedness and awareness.
The development of a National Flood Management Action Plan is strongly recommended in each of the riparian countries of the Mekong Basin which will define strategy and priorities, promote investments, capacity building and training at all levels and ensure cooperation between national agencies and ministries as well as coordinate regional cooperation and support.
To plan and implement the national flood management action plan, the Flood Management Unit needs to be reinforced to define flood mitigation measures, to monitor annual floods and to create national and local preparedness for floods.