Water Management in the Mekong Delta- Changes, Conflicts and Opportunities pps

INTERNATIONAL HYDROLOGICAL PROGRAMME
_____________________________________________________________
Water Management in the Mekong Delta:
Changes, Conflicts and Opportunities
by
Ian White
Centre for Resource and Environmental Studies
National Institute for the Environment
Institute of Advance Studies
The Australian National University
Canberra ACT 0200 Australia
_____________________________________________________________
IHP-VI
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Technical Documents in Hydrology
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No. 61
UNESCO, Paris, 2002
The designations employed and the presentation of material
throughout the publication do not imply the expression of any
opinion whatsoever on the part of UNESCO concerning the
legal status of any country, territory, city or of its authorities, or
concerning the delimitation of its frontiers or boundaries.

SC-2002/WS/47
CONTENTS
Terms of Reference 3

Acknowledgments 4
Summary 5
1. The Mekong 8
1.1 River of Change 8
1.2 This Study 11
1.2.1 Purpose 11
1.2.2 Study methods 11
1.3 Geography of the Mekong River Basin 12
1.4 The Lower Basin 14
1.4.1 Lower Basin Climate 14
1.5 Fisheries Resources of the Mekong 15
1.5.1 Wild capture fisheries 15
1.5.2 Future demands and threats to wild capture fisheries 16
1.5.3 Aquaculture 16
1.5.4 Constraints to aquaculture 17
1.6 Social, Cultural and Economic Features of the Basin 18
1.7 Institutional Arrangements for Mekong Basin Resource Management 20
1.7.1 The Mekong River Commission 21
1.8 Basin Development and Cooperation 23
2. The Mekong Delta 25
2.1 The Delta at Large 25
2.2 Vietnam’s Lower Delta 25
2.3 Cambodia’s Upper Delta 28
2.4 Hydrology and Climate of the Delta 30
2.4.1 Floods and seawater intrusion 31
2.4.2 Tidal influences 32
2.4.3 Seawater intrusion floodgates 33
2.5 Surface Water Quality 35
2.6 Groundwater in the Delta 36
2.7 Soils of the Delta 38

2.8 Acid Sulfate Soils 39
2.8.1 Oxidation of acid sulfate soils 40
2.8.2 Release of toxic metals 40
2.8.3 Discharge of acidity into surface waters 41
2.8.4 Impacts of acidity on estuarine ecosystems 41
2.8.5 Links between soils, hydrology and atmospheric emissions 42
2.9 Saline Soils 43
2.10 Water and Land Constraints 43
2.11 Integrated Management and Conflict Resolution 44
2.11.1 The use of multi-agent systems in natural resource management 44
3. Responses to Water and Land Issues of the Delta 47
3.1 Completed Projects of the Mekong Secretariat 47
3.1.1 Salinity intrusion forecasting 47
3.1.2 Water balance study 48
3.1.3 Water quality monitoring 49
3.1.4 Management of acid sulfate soils 50
2
3.2 Work Plan of the Mekong River Commission Secretariat 51
3.3 The Mekong Delta Master Plan 53
3.4 Saline Intrusion Floodgates 54
3.5 Sedimentation and Hydrology of the Great Lake 56
3.6 Perspectives for Australian Development Cooperation 56
3.7 Australian Centre for International Agricultural Research Projects 57
3.8 The Farmers Response 58
3.9 Summary 58
4. Opportunities for Integrated Research 60
4.1 Management and Impacts of Saline Intrusion Floodgates in the lower Mekong Delta.61
4.1.1 Background 61
4.1.2 Overall Objectives 62
4.1.3 Specific Objectives 62

4.1.4 Expected Outcomes 62
4.1.5 Beneficiaries 62
4.2 Sedimentation and its Impacts on Cambodia’s Great Lake 62
4.2.1 Background 62
4.2.2 Overall Objectives 63
4.2.3 Specific Objectives 63
4.2.4 Expected Outcomes 64
4.2.5 Beneficiaries 64
4.3 Dry-Season Groundwater Supplies in the Mekong Delta 64
4.3.1 Background 64
4.3.2 Overall Objectives 65
4.3.3 Specific Objectives 65
4.3.4 Expected Outcomes 65
4.3.5 Beneficiaries 65
References 66
3
Terms of Reference
The terms of reference for this report are to prepare a state-of-the art monograph on the
Mekong Delta which addresses:
(i) a succinct summary of past and present hydrology and water resource management
activities, including those under the auspices of the Mekong River Commission and of
other specialised agencies.
(ii) a critique of existing and past projects in terms of their success rate of implementation;
(iii) recommendations for future inter-disciplinary and inter-agency projects in the broad
field of land-use (water management) which require an integrated approach at the
subregional level on water management issues. The recommended programme should be
able to attain achievable results within 3 years, take into account any limitations on-site
infrastructure and incorporate the socio-cultural aspects of water management (i.e.
community water management) in the proposal.
(iv) to submit one copy of the manuscript as well as a typewritten mission report to

UNESCO.
4
Acknowledgments
This work was sponsored by the United Nations Scientific and Cultural Organization,
UNESCO, and supported by the Australian Centre for International Agricultural Research,
ACIAR and Centre for Resource and Environmental Studies Australian National University.
The author wishes to thank Dr Mike Bonell, UNESCO-IHP, Dr Fereidoun Ghassemi, CRES,
ANU, Hugh Milner and Andy Marr, SMEC, Brian Cummins, Cummins and Associates, Dr
Philip Ford, CSIRO Land and Water, Dr Ian Willett, ACIAR, Associate Professor Mike
Melville, University of NSW, Dr Phillip Gibbs, NSW Fisheries, Dr Philip Hirsch, University
of Sydney, Professor Vo-Tong Xuan¸ Dr Le Quang Minh, Professor Vo Quang Minh,
Nguyen Anh Tuan, Dr Troung thi Nga and Dr Nguyen Huu Chiem , Cân Tho University,
Vietnam, Dr Pascal Perrez, CIRAD, France, Ms Erica Donner, CRES ANU, Dr Truong and
Mr Nguyen Than Tin Sub, Institute Water Planning, Vietnam, Professor Nguyen An Nien
and Professor Dong, Southern Institute of Water Resources Research, Vietnam, Dr To Phuc
Tuong, IRRI, the Philippines, and Dr Sok, Hydrology, Mekong River Commission for
assistance and many helpful discussions. Mr Vincent Leogardo, UNESCO IHP, is thanked
for his generous help in preparing this report.
5
Summary
The Mekong River is one of the few great, largely unregulated rivers of the world. Its Delta
is both agriculturally and aquatically highly productive and a major contributor to the
region’s food production and export earnings. Water and land issues of the Delta must be
considered as integral with those of the Mekong Basin as a whole. A majority of the Mekong
Basin’s 60 million, ethnically diverse peoples rely on the River’s aquatic resources and rice
production for their subsistence. For many, 40 to 60% of their protein intake is from fish
from the Mekong. The prodigious fish resources rely on the annual fllooding of the Mekong.
The marked seasonal ebbs and flows of the River also impose severe constraints on its
riparian communities, with vast wet season floods and dry season water shortages that allow
seawater intrusions into the Delta.

These annual hardships are superimposed on nearly 60 years of devastating external and
internal conflicts in the region. The six riparian countries making up the Basin have generally
low external and per capita earnings. Harnessing the Mekong for hydropower generation and
irrigation supplies, through cascades of main-stream and tributary dams, coupled with
harvesting the Basin’s forests are ways of stimulating growth, increasing per capita income
and regulating seasonal flows. These developments, however, are potentially in conflict with
the subsistence needs and the livelihood security of the region’s poorest people. River
regulation and diversions pose dilemmas, since they may decrease substantially the
Mekong’s prodigious aquatic productivity. Up-catchment forestry also threatens water
quality, productivity and dam capacity through potential increased sediment loads.
The Mekong River Commission’s task is to plan the sustainable development, use,
conservation and management of the River’s water and related resources in mutually
beneficial manner and to channel resources into its work program. Understanding the
hydrology of the Basin and impacts of its regulation are central themes in its work plan,
financed mainly by international multilateral or bilateral organisations. Major financing
organisations have been criticised by non-government organisations as too narrowly focussed
on infrastructure development and reliant on top-down approaches which ignore the needs of
people. A key issue, identified by both proponents and critics of regulation structures is the
paucity of reliable data on climate, hydrology, sediment yields, capture fisheries, social,
economic and cultural aspects upon which to base sound decisions. In some important areas,
such as water quality monitoring, the magnitude and complexity of water quality concerns
are increasing at a rate that exceeds the capacities of riparian countries.
The low-lying Mekong Delta faces unique water land issues because of its sedimentary
composition and geomorphology. The issues of Vietnam’s lower Delta differ from those of
Cambodia’s upper Delta, which is dominated by the Delta’s natural flow regulator, Tonle
6
Sap and Cambodia’s Great Lake. In Vietnam’s lower Delta, the major land and water
resource problems are: acute flooding in the wet season, with flood depths of more than 4 m
in the northern Delta; acid sulfate soils constraints on crop productivity in over 40% of the
lower Delta and associated, severe, acidic drainage waters with major implications for

aquatic productivity; seawater intrusion in the dry season in the lower Delta, limiting rice
production to one crop per year in saline intrusion areas; impacts of seawater intrusion
floodgates on acidification; loss of coastal mangroves and impacts on coastal protection and
fisheries.
In the Cambodia’s upper part of the Delta different issues need to be addressed. There is a
surprising dearth of information on sediment fluxes and on the quantitative relation between
flooding and the breeding/ feeding/ life cycle of fish despite their importance to riparian
communities. The principle water and land concerns in the Cambodian section of the
Mekong Delta are: impacts of upstream flow regulation on the water supply for flooding for
rice production and fish production in the Great Lake; impacts of forest clearing on
sedimentation and aquatic production in the Great Lake; impacts of downstream river
regulation on flooding, rice and fish production. Recent estimates of sedimentation rates in
the Great Lake are at least 8 times higher than those of the past 5,000 y. In both the upper
and lower Delta, the availability and quality of domestic water supplies is a major issue. The
control of downstream flooding and of saline intrusion in the lower Delta could be
potentially in conflict with the need to reduce flooding in the upper Delta.
In the past, projects relevant to the specific needs of the Delta have tended to be narrowly
focussed. The highest priority has gone to planning and design for hydropower and irrigation
diversion. Main projects completed by the Mekong River Commission Secretariat with direct
relevance to the Delta are: the Saline Intrusion Studies; the Water Balance Studies; the
Management of Acid Sulfate Soils Project; and the Water Quality Monitoring Programme.
Even in these, the central thrust has been the impacts of upstream regulation, diversions to
increase crop production and changes in landuse on the quantity of water in the Delta.
Broader issues such as the influence of saline intrusion on fish production and the
importance of recent sedimentation to aquatic and terrestrial productivity have not been
examined. The Secretariat’s present Work Plan still has a concentration of effort on
infrastructure development but there are broader-based projects planned and underway.
The Secretariat’s water balance, salinity intrusion and acid sulfate soil management projects
formed the basis of the Mekong Delta Master Plan, intended to underpin sustainable growth
in the lower Delta. A central thrust of this plan is increased rice and aquaculture production.

A key outcome of this plan was a proposal to increase rice production in the region west of
the Bassac by supplying a longer irrigation season and lowering or preventing salt-water
intrusion into the region. This proposal, the Desalination of the Ca Mau Peninsula, has
recently been completed. It is suggested, by analogy with the Australian situation that the
impacts of this project on local fish production and waterway acidification may be severe
with significant consequences for local communities. The impacts of already installed sluice
gates near Soc Tranh were summed up succinctly by one farmer “floodgates have given us a
road (track) and electricity. But no crops and no fish!”
A seminal, French benchmark study of sedimentation in Cambodia’s Great Lake provides an
opportunity of assessing the impacts of changes in upcatchment and surrounding landuse on
sediment and nutrient dynamics and fish production in the Lake. A comprehensive report to
7
the Australian government, Perspectives for Australian Development Cooperation, identified
key areas for assistance in the Delta because it receives less priority development assistance
and because of the concentration of poor there. Salinity and acid sulfate soils required
assistance. It recommended an integrated approach to acid sulfate soils because they involved
cross-sectoral land and water issues and one which was both precautionary and curative. The
report also pointed out the uncertainty of dry season domestic water supplies in the Delta and
the problems with acidity and salinity. Groundwater was seen as an increasingly important
resource in these areas. Watershed and catchment planning were also identified as
opportunities for assistance. The farmer’s response to the adverse conditions they face daily
has been innovative and courageous.
Three proposed integrated projects for the Mekong Delta were developed out of the above
analysis: Management and Impacts of Saline Intrusion Floodgates in the lower Mekong
Delta; Recent Sedimentation and its Impacts on Cambodia’s Great Lake; and Dry-Season
Groundwater Supplies in the Mekong Delta. Brief backgrounds, overall objectives, specific
objectives, expected outcomes and beneficiaries are given for these projects.
8
1. The Mekong
1.1 River of Change

The Mekong (Thai: Mother of Waters) River has the twenty-first largest drainage basin and
is the twelfth longest river with the eight largest annual discharge and second most diverse
riverine fishery in the world. It is one of the world’s great, largely unregulated rivers. The
water, land and biological resources of the Mekong Basin sustain an ethnically diverse and
growing population in six countries; China, Burma, Lao PDR, Thailand, Cambodia and
Vietnam (Fig 1.1). The Mekong Basin’s resources provide both great benefits and hardships
for its peoples. The river is biologically highly productive and is a major source of protein.
Its wet season floods nurture vast rice crops. However, wet season flooding is severe with
over 50% of the Mekong Delta (1.9 Mha) annual inundated. The floods of 1961, 1978,
1991, 1996 and 2000 caused major devastation and all except the 1996 flood had return
intervals of greater than 1 in 50 years. Paradoxically, water shortages arise in the dry season,
particularly in southwestern region of the Mekong Delta. These water shortages lead to
seawater intrusion in streams in the lower Delta. Seawater intrusion, severe acid sulfate and
saline soils and upstream deforestation impose social and economic constraints and
uncertainties and limit agricultural production of staples such as rice and fish (Be, 1994;
Minh, 1995). The seasonal extremes, however, are necessary to sustain the Basin’s
exceptional aquatic productivity (Roberts, 1993a) on which its riparian communities depend
for most of their protein.
Since the 1930’s the Basin has been ravaged by wars of liberation and inter and intra country
conflicts. These have had massive, long-term social, economic and cultural impacts on the
peoples of the lower Basin and depleted populations, resources and institutional capacity,
especially in resource management. International organisations are seeking to assist the
region’s peoples by promoting development and growth in the Basin, mostly through large
infrastructure construction projects, principally hydropower, flood mitigation and irrigation
supply dams. The Mekong is seen by many as one of the great “undeveloped resources” of
Southeast Asia. Less than 5% of both the Basin’s annual flow and its catchment are regulated
at present. There are plans for a cascade of up to 9 mainstream “run-of-river” hydropower
schemes in the Mekong together with as many as 50 tributary dams (Rothert, 1995). These
plans have been criticised as fundamentally flawed (White, 1997) because of the dearth of
information on climate, hydrology, ( Institute of Hydrology, 1982; 1984; 1988a, 1988b) and

ecology, as well as a paucity of social, economic and cultural data and knowledge of the
aspirations of riparian communities likely to be affected by river regulation (Greater Mekong
Task Force, 1996).
9
The Basin is undergoing accelerating, political, cultural, economic, and water and land use
changes. These changes have the potential to both benefit individual countries and to
disadvantage their downstream or upstream neighbours as well as their own riparian
communities. River regulation and changed landuse have major implications for the
sustainability of many rural communities along the River (Derasary, 1996).
10
Fig. 1.1 The lower Mekong River Basin flowing from China to the South China Sea (Mekong
River Commission, 1999)
11
Clearing of upstream forests has reportedly changed rainfall-runoff relations, resulting in
larger, more frequent floods (Hirsch and Cheong, 1996) and an increase in dry season flows,
primarily as a result of reservoir construction on tributaries (Institute of Hydrology, 1988a).
The frequency of major 1 in 50 year floods over the past 40 years is a of major concern,
especially in the Delta. These factors, coupled with the putative impacts of global climate
change, which suggest an increase in frequency of extreme events but with overall lower
mean river flows for the Mekong (Lettenmaier, 2000) have led to increasing calls for
regulation of Mekong flows.
Most major projects in the Basin or proposed projects have been criticised as narrowly
focussed, involving a single or a small number of infrastructure-dependent outcomes (White,
1997). This is particular so in developments for flood mitigation, irrigation supply,
hydropower generation or seawater intrusion mitigation. Such schemes have been faulted for
their perceived lack of appreciation of the broad range and complexity of issues that need to
be considered and the gamut of deleterious impacts that may ensue (White, 1963; Fraser-
Darling, 1970; Challinor, 1973; Roberts, 1993b; 1995; Sluiter, 1993; McCully, 1996; Hirsch
and Cheong, 1996).
1.2 This Study

The issues involved in the equitable management and sharing of the whole Basin’s resources
while retaining local sovereignty and protecting local interests are complex. It is clear that
the availability and sharing of knowledge on the prevailing hydrology, climate, ecology,
economics, sociology and cultures and listening to and addressing the aspirations of its
peoples are fundamental to the development, use and management of this vitally important
Basin. The issues in the Mekong Delta mirror those of the Basin as a whole but also present
some unique problems because of the Delta’s geomorphology.
1.2.1 Purpose
The purpose of this study is to overview broad issues in the Mekong Delta, to examine the
success and failures of hydrologic developments in the Delta and to identify gaps in current
hydrologic knowledge which require a broader, integrated approach to their solution in order
to use and manage water and land resources of the Delta sustainably and equitably. It is
undertaken at a time when major infrastructure developments are under way, and when
important studies are being carried out such as the review of water quality monitoring
(Ongley et al., 1997) and the Mekong River Commission-Murray-Darling Basin
Commission/SMEC Mekong River Utilisation Program (H. Milner, private communication,
Nov. 1997) to develop Basin-wide water use and management rules. Like the River itself, the
situation is fluid and constantly changing.
1.2.2 Study methods
In this study, relevant, accessible publications and documents were reviewed, discussions
were conducted, particularly with current study teams, and a field trip to the lower Delta was
carried out in May 1997 with the assistance of the Australian Centre for International
12
Agricultural Research (White et al., 1997b). Because the Delta is an integral part of the
Mekong and will bare the brunt of any large-scale changes in upstream hydrology, it is
necessary to first consider background and status of the Mekong Basin as a whole before
focussing on the Delta.
1.3 Geography of the Mekong River Basin
The Mekong River rises 5,000 m above sea level, where it is fed primarily from snow-melt
in the Tanghla Mountains on the Tibetan plateau. It descends through steep, narrow gorges

in south-western China, where it is called the Lancang (Turbulent) River, passes through the
‘Golden Triangle’ junction of Burma, Laos and Thailand, at an elevation of about 500m,
crosses the highlands of Laos. It then forms a 900 km boundary between North-East Thailand
and Laos, before descending the Khone Falls in southern Laos and 120 km of rapids in
northern Cambodia (see Fig 1.1). After its confluence with the Tonle Sap River at Phnom
Penh at the ‘Quatre Bras’, the Mekong splits into the 220 km long Bassac River and the 240
km Mekong, which runs almost parallel to the Bassac. These flow into the Mekong Delta
through the 9 tributaries of the Cuu Long, the “nine dragons”, and out into the South China
Sea at the end of its 4,200 km long journey (Pantulu, 1986; Sluiter, 1993; Mekong
Secretariat, 1994; Hisrch and Cheong, 1996). The maximum width of the Mekong in the
Delta during non flood periods is close to 1.2 km at Vam Nao. A summary of biophysical
and landuse data of the Basin is given in Table 1.1.
T
ABLE
1.1 Biophysical and landuse data for the Mekong River Basin (Hirsch and Cheong,
1996).
Burma Cambodia Lao PDR Thailand Vietnam Yunnan Total
Drainage Area
(10
3
km
2
)
24 155 202 184 65 165 795
Basin Area
(%)
2 20 25 23 8 21 100
Annual Runoff
(%)
2 1835181116100

Forest Cover
(%)
47
(whole
country)
49-62 47 26 27 - -
Rate of
Deforestation
(%)
6
(whole
country)
3 2 1.5 3.2
(Central
Highlands)

Arable Land
(10
3
km
2
)
95.7 29.1 8.9 190 56.9 933
-
Irrigated Land
(%)
-152020
(northeast)
40-50
(Delta)

-
-
Hydropower
Potential
(MW)
300 2200 13200 1000 2000 13000 31500
Hydropower
Potential
(%)
17423641
100
13
The 795,000 km
2
Mekong Basin covers a wide range of bioclimatic zones. Annual River
from the discharge from the Basin is 475 km
3
, or a remarkable 600 mm on a whole basin
areal average. The variation of annual runoff with drainage area down the Basin is shown in
Fig. 1.2 (Pantulu, 1986). The changes in runoff down the basin reflect the impact of
tributaries and the orographically-driven rainfall variation. The minimum between Kratie and
Phnom Penh represents natural regulation by Cambodia’s Great Lake fed and discharged
through Tonle Sap. Mean runoffs are misleading since the monsoonal climate results in an,
on average, 15-fold variation between low (April or May) and high (September or October)
flow. This flow variation imposes the combined annual hardships of wet seasons floods, and
water shortages and saline intrusion in the dry season on populations in the Mekong Delta
and leads to an inherent resource uncertainty in agricultural production, particularly in staples
such as rice, and water-supply related health problems.
0
100

200
300
400
500
0 200000 400000 600000 800000
Drainage Area (km
2
)
Mean Runoff (km
3
/y)
0
50
100
150
200
Sediment Load (Mt/y)
Chieng Saen
Vientiane
Mukdahan
Pakse
Kratie
Phnom Penh
South China Sea
Sediment Load
Runoff
Fig 1.2 Variation of mean annual runoff (line) and sediment load (solid square points) with
drainage area for the lower Mekong Basin. The dip between Krate and Phnom Penh
illustrates the natural regulation of Cambodia’s Great Lake and the Tonle Sap (from
Pantulu, 1986, Mekong Secretariat, 1982).

14
The sediment loads are relatively low (concentrations between about 0.2 to 0.8 kg/m
3
)
compared to other major Asian Rivers. The organic content of the sediments is high, about 6
to 8% of total suspended solids (Mekong Secretariat, 1982). Annual sediment loads down the
Basin are also plotted in Fig. 1.1. It can be seen that there is a mean net deposition of 35 Mt/y
of sediment at Phnom Penh, presumably during the flooding of the Great Lake.
Table 1.1 also lists the enormous potential for generating electricity from the fall of the
Mekong and its tributaries, particularly in Laos and Yunnan Province, China. Currently, the
only mainstream run-of-river dam on the Mekong is the Manwan hydropower Dam in
Yunnan Province (Kunming Hydroelectric Investigation, Design and Research Institute,
1993) . This hydropower potential has attracted strong interest because of its ability to
provide power for industrialisation and much needed external earnings for the riparian
countries of the Basin. In addition, hydropower dams can be used to provide irrigation water,
safe, reliable domestic supplies and to promote interbasin transfers. Major plans for cascades
of dams along the Mekong and its tributaries, however, have attracted mounting and
concerted opposition, particularly from community-based, non-government organisations.
These organisations argue that the full environmental, ecological, economic, social and
cultural costs of the hydropower cascades could exceed their benefits. For decades, river
regulation has been the central, contentious issue in the management and use of the Mekong
River Basin.
1.4 The Lower Basin
The lower Mekong Basin, downstream from China and the Burma-Laos -Thailand
intersection, covers parts of Lao PDR, northeast Thailand, 86% of Cambodia and 20% 0f
Vietnam. The lower Basin represents 77% of the total Basin area and more than 80% of the
annual flow. Much of the available data relates to the lower Basin because of the
composition of the previous Mekong Committee (the river’s former main institutional
management and development authority), as well as those of the subsequent Interim Mekong
Committee and now the Mekong River Commission (Lao PDR, Thailand, Cambodia and

Vietnam). The lower Basin’s resources are of particular interest to the member nations.
1.4.1 Lower Basin Climate
The lower Basin is in the centre of the Asian tropical monsoon region with a summer-winter
wind reversal due to differential heating of the extensive land and water masses. Its climate
is governed mainly by seasonal monsoon winds. The southwest, wet season monsoon starts
in mid March to mid-May and ends around mid-September to mid-October. The northwest
dry season monsoon runs from mid-October to March. Rainfall in the wet season is typically
afternoon or early evening, convective falls. In higher regions, rainfall is topographically
driven. A short 7-14 day dry period frequently occurs in June or July due to high anticyclone
circulation There are occasional tropical storms with large rainfalls in August and September
(Pantulu, 1986; Mekong Secretariat, 1968; 1975). Mean annual rainfall of the lower Basin
ranges from approximately 1,000 mm in northeast Thailand to more than 3,500 mm in the
mountainous fringe of northeast Laos, where there is no clearly defined dry season.
Elsewhere in the lower Basin, little rain falls during the dry season. Relative humidities
range from 50 to 98% and. mean solar radiation is estimated to be 1.12 MJ/m
2
/d. Estimated
annual potential evaporation ranges from 1500 to 1800 mm. The seasonality of rainfall
15
excess and its consequent impact on river and tributary flow, largely govern the water, land
and biological resources of the lower Basin., As it flows from the upper Basin to the lower
Basin, at Chiang Soen, the Mekong has a less pronounced seasonality in flow because of the
influence of upstream snowmelt.
1.5 Fisheries Resources of the Mekong
The Mekong is one of the most biologically diverse river systems in the world. Currently
1700 fish species have been recognised, although the list is by no means complete (Bao, et
al., 2001; MRC, 2002a). There is also a corresponding diversity amongst other aquatic
animals and insects. The annual flooding of the vast floodplains of the Mekong fuels this
diversity, by when fish take advantage of the vast expanse of rich feeding grounds and the
opportunities to breed, spawn and raise young. In the dry season, fish retreat to river channels

and to permanent lakes and deep pools in the river. This annual flooding means that fish
migration is the norm (Bao et al., 2001).
The Lower Mekong Basin has three major interconnected migration systems. The lower
system lies downstream from the Khone Falls, and includes the Tonle Sap River and Great
Lake system in Cambodia and the Mekong Delta. The middle system extends from above
Khone Falls to the Loei River. In this system, floodplain habitats are connected with the
large tributaries of the Mekong. The upper system runs upstream from the Loei River (MRC,
2002a). The complexity and interconnectedness of the migratory systems and the
fundamental importance of the annual flooding are some of the main reasons behind growing
opposition to regulating the main flows in the Mekong and to concerns over sediment loads
from cleared areas. The fundamental importance of the Tonle Sap River and Great Lake
system cannot be overstated.
Bao et al. (2001) highlighted the critical nature of habitat and flood patterns to the propensity
of fish species to migrate, spawn and find dry-season refuges. Changes in flood patterns or
water quality, blockage of important migration channels and destruction of dry season
refuges could all adversely affect fish stocks that are crucial to the health, nutrition and
livelihoods of some of the poorest people in the Lower Basin countries. Fish migrations
therefore have many implications for regional development, planning and management. They
recognised important fish stocks are shared between countries and concluded that joint
management strategies are needed to ensure appropriate development.
Many fish species migrate trans-boundary during their life cycle. Several migratory stocks
are shared, including the endangered Giant fish species. There are, however, no institutional
arrangements at the regional level for joint management of trans-boundary fish resources. At
the local level, there are long standing traditions of fisheries management being undertaken
by communities in the Lower Mekong Basin. Local rules on fishing are often connected with
spiritual beliefs. These help sustain local resource levels and to ensure equitable distribution
(MRC, 2002a).
1.5.1 Wild capture fisheries
Fish is the major source of protein for people in the lower Mekong Basin. It is estimated that
wild capture fisheries produce annually over 1.6 million tonnes (Bao et al., 2001; MRC,

2002a). The total value of the catches is about $US1.4B.The size of inland fisheries, however
16
has been grossly under-reported because of the subsistence nature of the sector (Mekong
River Commission, 1999). During a field trip to the lower Delta, fisheries experts had ample
data on aquaculture production but had no information and little curiosity about wild capture
fisheries. In boat trips along the canals it was evident that wild capture fisheries effort was
enormous with major netting structures at least every 50m.
Average fish consumption ranges from about 30 kg per capita in mountainous areas, to 70 kg
around the Great Lake Tonle Sap area in Cambodia. During the dry lean seasons, fermented
and dried fish are used in place of fresh fish and most households use fish sauce all year
round. Most fish are consumed locally or traded fresh at village, district and provincial
markets. There is also trade in fish within the Mekong Basin and its neighbouring
catchments. Exports are limited, but increasing (MRC, 2002a).
1.5.2 Future demands and threats to wild capture fisheries
It has been predicted that there will be a 20 percent increase in fish demand in the Lower
Mekong Basin over the next 10 years. Increased fishing may increase in overall catches in
the short term. This however will be accompanied by a continued decrease in the larger slow-
growing migratory species in the catches. To mitigate the decline in biodiversity will require
coordination and integration of management interventions at all levels. Current analyses
suggest there is no indication that future increases in fishing effort will lead to decreased
catches or reduced diversity for the non-migratory fish species(MEC, 2002). However, this
predicated on the major assumption that the integrity and spatial extent of the floodplains
remain intact.
The major threats to sustaining capture fisheries include (MRC, 2002a):
• Destruction of spawning grounds or dry season refuges by habitat alterations
• Local changes in the quantity and quality of water available for sensitive habitats and the
timing of hydrological events,
• Pollution from agriculture and urban development.
• Construction of dams, weirs or diversions which act as physical barriers to fish
migrations.

• Increased sediment load due to deforestation.
1.5.3 Aquaculture
Aquaculture in the Lower Mekong Basin is diverse and includes the production and sale of
fry and fingerlings and raising wild or artificially produced fingerlings in enclosed or semi-
enclosed water bodies. Total production Basin is estimated to be 260,000 tonnes per year
with a farm gate value of about US$ 270,000M. million. There are relatively few large-scale
commercial farms in the Lower Mekong, although there are large catfish farms in the Bassac
River and large integrated fish farms near towns and cities in Northeast Thailand. Most
aquaculture production comes from small-scale operations run by rural households and this
is becoming increasingly important throughout much of the Basin. Small-scale aquaculture
contributes to food supply in areas where wild fish are deficient. It also provides
opportunities for supplementary income and diversity. Except in Cambodia, fish ponds and
rice fields are the most common means of producing fish throughout the Basin (MRC,
2002a).
17
The Mekong Delta has the largest aquaculture area (330,000 ha) and freshwater production
is above 170,000 tonnes. An estimated 80,000 ha are presently under rice-fish culture, with a
mean annual production of 370 kg/ha. There are more than 100 hatcheries in the area and the
most commonly farmed species are catfish, barbs, carps, tilapia, gouramis and sand goby.
There are about 5,000 fish cages in the Delta that are mostly stocked with fry and juveniles
from the wild.
In Cambodia, most of the aquaculture production comes from cages and pens. River catfish
and snakeheads are the dominant species. Northeast Thailand is the second largest area in the
Lower Mekong Basin for aquaculture production. There production has expanded
significantly over the last decade and annual output is in the range of 65,000 tonnes. Cage
culture of tilapia has recently expanded in reservoirs and in the Mekong River.
Governments see aquaculture as a high priority. They support investments in aquaculture and
fund research, infrastructure, education and extension. As with many government
enthusiasms, effort is focussed on narrow outcomes without consideration of broader and
interconnected issues There is no separate legislation on aquaculture in any MRC-member

country. However it is under review in all.
Trans-boundary issues such as genetic quality of broodstock have yet to be addressed. There
are major environmental concerns about the more intensive forms of aquaculture. There
include :
• the balance between exotic and indigenous species,
• culture of predator species,
• collection of juveniles form the wild,
• water pollution and
• the spread of fish disease (MRC, 2002a):.
The past 10 years has seen five-fold increase in aquaculture production. Continued expansion
could contribute to meeting some of the needs for fish products in the Lower Mekong.
However, aquaculture sales are strongly influenced by market demand, particularly in the
local market. The demand will depend on the number of consumers who can pay the price,
often US$ 1.00 or more per kg.
Aquaculture growth in the lower Mekong needs an expansion in hatcheries and nursing
capacity. Centralised large government hatcheries have not been successful. Development of
local, small-scale hatcheries, trading networks, and on-farm breeding appear to offer more
promise in supporting rural, small-scale aquaculture (MRC, 2002a).
1.5.4 Constraints to aquaculture
There are several constraints to the development of aquaculture. Many of these are
institutional rather than technical. The capacity and resources of government institutions for
participatory extension and research is limited. Capacity building is required to support
development. The development of aquaculture to date has been a narrow sectoral approach.
It is now acknowledged that the promotion of aquaculture in the Mekong Basin should take
food security and poverty alleviation as a starting point for interventions and there needs to
18
be an emphasis on building capacity in local institutions. Aquaculture needs to be integrated
into fisheries projects and wider rural development strategies. Aquaculture, capture fisheries
and reservoir management are parts of a holistic system. The past focus on policy and
development efforts for aquaculture alone, while ignoring wild fisheries, could result in a

dramatic loss of fundamentally important wild fisheries resources. This could severely affect
food security for the entire Lower Mekong Basin, particularly for poor people (MRC, 2002a).
A recent analysis of finances and risks of selected aquaculture activities in the Basin
concludes that pond and cage aquaculture has high potential in Lao PDR, Cambodia and Viet
Nam, in terms of both commercial development and small-scale family enterprises directed
at poverty alleviation (MRC, 2002b). It found from a financial perspective, aquaculture
compares well with alternative traditional enterprises such as rice and fishing, and other new
enterprises such as fruit and coffee production. While risk levels were necessarily somewhat
higher than traditional activities, they were generally similar to, or lower, than other new
enterprise types.
The Mekong River Commission has espoused an individual catchment approach to resource
management in the Basin. This is designed to be a bottom-up planning and data gathering
process, with assistance from people whose livelihoods depend on the resources of the
catchments. It is modelled on catchment management throughout Australia’s Murray-Darling
Basin and elsewhere. There, it is probably too early to determine whether the voices of those
who depend on the catchment for their livelihood is truly heard.
1.6 Social, Cultural and Economic Features of the Basin
The lower Mekong Basin has an estimated population of 60 million. About 45-50 million of
these inhabitants are farmers and fishers relying directly on the Mekong River and its
associated land resource (Mekong River Commission, 1999). This population is ethnically
very diverse. Only in Cambodia does one ethnic group, the Khmer, dominate the country’s
basin area. In China, minorities exceed the Han Chinese. Lao PDR has 68 ethnic groups.
Vietnam’s Delta population is mainly Kinh but concentrations of Khmer, Chams and ethnic
Chinese exist there. Economic indicators for the Mekong’s riparian countries are listed in
Table 1.2.
T
ABLE
1.2. Economic indicators of Mekong River riparian countries (Kirsch and Cheong,
1996)
Burma Cambodia Lao PDR Thailand Vietnam Yunnan

GDP
(billion US $)
11 2.03 1.46 140.3 17.4 4.51
GDP per capita
(US $)
250 206 335 2377 240 465
GDP Annual
Growth Rate
(%)
6.4 4.9 8.0 8.5 8.8 11.8
GDP Agriculture
(US $)
47.1 44.8 57.4 11.1 32.3 21
19
Burma Cambodia Lao PDR Thailand Vietnam Yunnan
GDP Industry
(US $)
14.4 19.6 17.9 42.1 25.3 54
GDP Industry
(US $)
38.5 35.6 24.8 46.8 42.4 25
Trade Balance
(billion US $)
-0.724 -0.243 -0.205 -9.5 -0.9 -
Current Account
Balance
(billion US $)
-0.294
(1994/95)
- -0.104

(1992)
-8.4
(1994)
-1.1
(1994)
-
Foreign Debt
(billion US $)
5.5
(1993/4)
1.0
(1992)
1.92
(1992)
27.4
(1994)
19.6
(1994)
-
Consumer Price
Increase
(%, 1994)
35 26.1 6.7 5 9.9 21.7
The average level of income between countries in Table 1.2 varies by a factor of 10. This is
somewhat misleading in regard to income derived from the Basin. The northeastern region of
Thailand is the country’s poorest, while the Delta is Vietnam’s most prosperous region. In
addition, in the Delta most income comes from local farm or aquatic production whereas a
significant proportion of income in northeastern Thailand comes from off-farm remittances.
The figures in Table 1.2 take no account of the late 1997 financial crises in Asia and are
indicative only of relative wealth of countries within the Basin. Financial crises have major

implications for the development and management of the Basin. It is quite clear from Table
1.2 that most of the Basin’s inhabitants are subsistence farmers and fishers. In the lower
Mekong Basin, fish is as important to riparian communities as rice (Sluiter, 1993) and makes
up 40-60% of protein intake (Pantulu, 1986). The limited and dated information on fish
consumption shows that the average annual per capita fish consumption in Cambodia was
25.4 kg which exceeds others in the lower Basin, with Vietnam 20.8 kg, northeast Thailand,
11.5 kg and Laos, 10.2 kg (University of Michigan, 1976). These figures, however, must be
considered approximate.
In subsistence economies, there are clearly extremely limited internal resources to undertake
the necessary planing, monitoring, implementation and management of Basin-wide projects.
There are two main external, loans-funded resource developments proposed for the Basin,
hydropower and forestry. These are seen as important sources of national income and earners
of foreign exchange, however both activities are potentially at odds with the subsistence
needs and livelihood security interests of the region’s poorest people (Hirsch and Cheong,
1996), a issue emphasised by many non-government agencies working within the region. The
impacts of both hydropower and forestry developments on the productivity and biodiversity
of Mekong fisheries is a major concern (Roberts 1993b; 1995). Internal development projects
also have not been problem free. The thrust for increased rice production from the Mekong
Delta has seen farmers move into areas badly affected by salinity and acidity and has
generated the need for salinity intrusion protection.
20
1.7 Institutional Arrangements for Mekong Basin Resource Management
Table 1.3 (modified from Hirsch and Cheong, 1996) provides a summary of regional,
institutional evolution in the management of the Mekong Basin as an entity.
The Committee for Coordination of the Comprehensive Development of the Lower Mekong
Basin, or Mekong Committee as it became known, was established through funding provided
by the United Nation’s Economic Commission for Asia and the Far East, ECAFE, in order to
catalyse development of the Basin and to increase per capita income of the riparian countries
(ECAFE, 1957). The United Nations Development Programme, UNDP, has been a major
and consistent supporter of the Committee since its inception. Some have considered the

Committee as a type of Marshall Plan for mainland Southeast Asia (Jacobs, 1995). As a
consequence, the Committee and its successors have both coordinated resource management
in the Basin and channelled development assistance to approved projects. This dual role has
been seen by some as a potential conflict of interest.
The US Army Corps of Engineers and the US Bureau of Reclamation have long been
interested in large scale engineering works on the Mekong and its tributaries. They saw the
annual flooding of millions of hectares of Mekong lowlands as the major impediment to
modernizing the region’s agriculture (Gráiner Ryder in Sluiter, 1993). Their solution was to
propose impoundment of water in large storage dams, from which controlled releases would
feed all-year-round, export-crop production and would generate income-earning hydropower.
The Corps report (United Nations, 1958), together with the Basin Indicative Plan (Mekong
Secretariat, 1970), which was a synthesis of earlier projects, formed the basis for planned
Basin development. The Mekong Committee and its successors have been seen by some
critics as being progeny of the Corps of Engineers, having a “one dimensional”
preoccupation with infrastructure construction, despite the existence of contemporary studies
of the non-engineering aspects of Basin development (White, 1963).
T
ABLE
1.3. Evolution of institutional arrangements for the management of the Mekong Basin
Year Institutional Development
1957
Formation of Mekong Committee
1970
Indicative Basin Plan
1971
Nam Ngum Dam Completed
1975
Cambodia withdraws from Mekong Commission
1978
Interim Mekong Committee established

1987
Revised Indicative Basin Plan
1992
ADB commences Greater Mekong Subregion Initiative
1994
Hanoi agreement on Cooperation for the Sustainable Development of the Mekong
River Basin
21
Year Institutional Development
1995
“Run-of-River” mainstream hydropower dams proposed
Mekong River Commission established
1999
Restructuring of the Secretariat to achieve its goals
The withdrawal of Cambodia under Pol Pot regime forced the Mekong Committee into
abeyance in 1975. In order to fill the vacancy, Vietnam, Thailand and Laos formed the
Interim Mekong Committee in 1978. This remained almost dormant until the mid 1980’s
when a Revised Indicative Plan was developed and released (Interim Mekong Committee,
1988). Disagreements arose in the early 1990’s on the procedures under which one member
country could veto plans of another and also on the conditions for the re-entry of Cambodia.
1.7.1 The Mekong River Commission
The Mekong River Commission came into being in 1995 after UNDP-sponsored meetings
culminated in the signing of the draft of the Agreement on the Cooperation for the
Sustainable Development of the Mekong River Basin, on 28 November 1994. The four lower
Mekong riparian countries endorsed this draft Hanoi agreement. It was based on the
principles of sovereign equality, territorial integrity and environmental protection to enable
the four signatory countries to use the resources of the Mekong in a reasonable and equitable
manner. The Agreement provided freedom of navigation throughout the mainstream Mekong
to promote regional cooperation and development. Importantly, it allowed for adding new
members to the Commission, but removed the right of individual country veto.

The four countries also adopted the concept of a Basin Development Plan to identify and
prioritize joint and basin-wide projects for action. Geography, hydrology, environment,
climate and the rights and interest of all riparian countries were to be accommodated in the
Plan. It has been seen by some as significant that the UNDP press release on the Agreement
failed to mention the rights and interests of riparian citizens of the Basin when it recognised
the need to harness the “destructive power of the River during peak wet seasons.”
The mandate of the Mekong River Commission is:
To cooperate and promote in a constructive and mutually beneficial manner
in the sustainable development, utilization, conservation and management of
the Mekong River water and related resources for navigational and non-
navigational purposes for social and economic development and well-being
of all riparian States, consistent with the need to protect, preserve, enhance
and manage the environmental and aquatic conditions and maintenance of
the ecological balance exceptional to this river basin.
The Commission’s vision for the Basin is:
22
An economically prosperous, socially just and environmentally sound
Mekong River Basin.
The mission of the Commission is:
To promote and coordinate sustainable management and development of
water and related resources for the countries’ mutual benefit and the
people’s well-being by implementing strategic programmes and activities
and providing scientific information and policy advice (Mekong River
Commission, 1999).
The Mekong River Commission consists of three permanent bodies. There are: the Council,
at Ministerial and Cabinet level which makes policies, decisions, and resolves differences;
the Joint Committee at permanent secretary level to carry out policies; and the Secretariat,
responsible for technical and administrative support for the Council and the day-to-day
operations of the Commission. The priorities of the Council can be judged from the work
programme of the Secretariat which concentrates on four major areas of work: policy and

planning; environment and monitoring; resources development and management; and
programme support (Mekong River Commission Secretariat,1995, Mekong River
Commission, 1999). More recently the Commission has reorganised its work into three
programmes (Mekong River Commission, 2002):
• The Core Programmes consisting of :
− the Basin Development Plan
− the Water Utilisation Programme
− the Environment Programme.
• Support Programmes which sustain the implementation of other MRC programmes
through a Capacity Building Programme.
• The Sector Programmes focus on specific sectors and address regional issues that are
significant to the management of the entire Mekong River Basin. There are 5 Sector
Programmes:
− the Fisheries Programme.
− the Agriculture, Irrigation and Forestry Programme.
− the Water Resources and Hydrology Programme.
− the Navigation Programme.
− the Tourism Programme
The Secretariat’s Water Resources and Hydrology Programme, a key programme in the
overall planning and management of the Basin, has four main components: monitoring; real-
time forecasting; planning and design; and applications. Present and planned projects of the
programme include improvement of the Basin-wide hydrometeorological network,
groundwater investigations, flood forecasting and damage reduction, upgrading of salinity
intrusion forecasting in the Mekong Delta, water balance of the lower Mekong Basin, Phase
IV and Mekong morphology and sediment transport. The Programme is seeking funds for
several of these projects.
23
The early 1990’s also saw sweeping changes in natural resource management within member
countries. The most significant of these was the creation of ministries specifically concerned
with the environment in each of the member countries. In order to meet these changing

circumstances the Secretariat was restructured in 1999. Its operational structure is shown in
Fig. 1.3 (Mekong River Commission, 1999).
Fig. 1.3 Operational structure of the Mekong River Commission Secretariat (Mekong River
Commission, 1999)
1.8 Basin Development and Cooperation
One of the important rôles of the Mekong River Commission is to act as a channel for Basin-
wide development assistance. The three most important multilateral or international agencies
involved in large scale Mekong project financing and administration are the Asian
Development Bank, the World Bank and the UNDP. Other UN agencies, such as UNESCO,
UNEP and ESCAP also play important rôles in heritage listing, and providing training for
resource assessment and management. A variety of bilateral agencies, from Australia,
Canada, Denmark, the European Union, Germany, Japan, Sweden, the UK and the US, also
provide important assistance.
The 1990’s saw a marked increase in the number of non-government organisations operating
in the Mekong Delta. Their main rôles in natural resource management has been at the
community level, in advocacy for community rights and environmental values and in
community capacity building. Many of these organisations have been strident in their
criticisms of projects planned or undertaken by the Asian Development Bank (Uramoto et
al., 1997; Imhof; 1997a), the World Bank (Imhof, 1997b) the UNDP (Probe Alert, 1995) and
Japan (Lammers, 1997) whom they accuse of “ignoring people and embracing top-down
Policy Decisions (CEO)
Planning
Information Analysis/
Environmental monitorin
g
Implementation