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GROUNDWATERIN MEKONG DELTAIN MEKONG DELTA
Bui Tran Vuong, Ph.D.hPham Van Cuong, Eng.
DIVISION OF WATER RESOURCES PLANNINGAND INVESTIGATION FOR THE SOUTH OF VIETNAM
ContentsContents
d i1. Introduction
2. Physical backgroundy g
3. Legal and institutional framework
4 Problem descriptions4. Problem descriptions
5. Research questions and objectives
6. Data availability
7 Training needs and capacity development7. Training needs and capacity development
8. Expectations from the project
1 Introduction1. Introduction• Map of the study area
1 Introduction1. Introduction
Social and economics•Area: 3.957 M ha, •Population: 16.7 M, •13 provinces. •50% of food prod, 70% f f it d•70% of fruit prod.
•80% fish production> 80 % t i•> 80 % export rice
1 Introduction1. Introduction(Ground)Water resources development and management
State Responsibilities for Water Resources Management.
• The Government carrying out unified state management on water resources
• The Ministry of Natural Resources and the Environment y(MONRE) implementing state management on water resources
• Ministries, ministerial level agencies implementing state management on water resources according to assignments given by the Government
• People’s Committees (provincial level) being responsible for state management on water resources within their localities
(Ground)Water resources development and management
1. IntroductionProblems and challenges• Water availability/sustainable levels of extraction at a aquifery q
scale. There is now an urgent need to define the sustainablelimits of groundwater extraction at local (aquifer) levels, andto manage total extractions within those limitsto manage total extractions within those limits.
• Integrating groundwater considerations into broad socio‐economic development planning. Groundwater resource
il bili d l bili ll i i b iavailability and vulnerability to pollution is not beingconsidered in the socio‐economic development planningresulting in potential investment in unsustainableg pdevelopment.
• Groundwater quality protection issues includet i ti f d t b l d ti iti bcontamination of groundwater by land use activities, bore
construction and abandonment, salinity intrusion andarsenic liberation.
1. IntroductionP bl d h llProblems and challenges• Groundwater planning. A suitable model for integrated
groundwater management planning that addresses thegroundwater management planning that addresses theissues discussed above on a system (aquifer or group ofaquifers) basis, including extraction limits, water sharing,
t l l t t f i t iwater level management, management of impacts on riversand other dependent ecosystems, and water qualityprotection, has not yet been developed.p , y p
• Monitoring of groundwater: The current poor level ofgroundwater survey is proving a major impediment todecision making and is seriously impeding the application ofdecision making and is seriously impeding the application ofIWRM approaches to groundwater management.Groundwater status and water extractions and data
l d h fmanagement issues include characterisation of resources,monitoring groundwater status and behaviour, monitoring ofextractions and data sharing.e t act o s a d data s a g
1. IntroductionProblems and challenges• Awareness. At both the central government and provincial
levels there is generally very poor appreciation oflevels, there is generally very poor appreciation ofgroundwater management issues, in particular the need toconsider groundwater in socio‐economic development. Ath i l l h i l f hthe community level, there is even less awareness of theneed to conserve groundwater resources and of the impactspeople’s activities have on groundwater.p p g
• Strengthening legal/administrative frameworks. The legaland administrative frameworks are currently poorlyd l d d t ll ll d t ddeveloped and are not generally well understood.
• State water management capacity. State groundwatermanagement capacity is currently very limited. Themanagement capacity is currently very limited. Thegroundwater bureau within DWRM is far too small innumber and capacity to undertake the significant tasksassigned to itassigned to it.
1 Introduction1. Introduction
• Previous and on‐going projects and researches
2 Physical background2. Physical background
G h lGeomorphology•Average elevation of 0.7 to 1 2 m except for some high1.2 m, except for some high hills in the northern delta province of An Giang•Along the Cambodian border, elevation is from the 2.0 to 4 0 m high then lower to the4.0 m high, then lower to the central plains in the 1.0 to 1.5 m high, and only 0 0.3 to 0, 7
i th tid l t lm in the tidal, coastal area.
2. Physical backgroundGeology
Bedrocks in the MD vary in yage from the D‐C‐1 to Eocen‐Oligocen, E2‐3 period
Cover sediments vary in age N to Qperiod
N‐Q sediments are grouped into formations h i diff l i lhaving different geological ages.
Each formation, sediments are further classified into sub‐formations having gdifferent types of sediment origins
2. Physical backgroundGeology
(a)‐ alluvial; (am) – alluvial‐marine; (ab) – alluvial‐swamp; (m)‐marine; (mb) –marine‐swamp; (b) – swamp; (mv) – marine – eoluvial; (bm) – swamp‐marine;
2. Physical background
Geology
2 Physical background2. Physical background
P i i iPrecipitation• The average rainfall of
i t l 1800approximately 1800 mm,
• uneven distribution both in space and timespace and time.
• The western region has the most rainfall with annualmost rainfall with annual average from 2000‐2400 mm, while the east has from 1600‐1800 mm rainfall on average.
2 Physical background2. Physical background
TTemperature
•The annual average i i
28 500
29.00
Annual Average Temperature
temperature varies in range of 26.5‐28oC. The lowest monthly temperature is 27 500
28.00
28.500
Bac Lieu
Ben Tre
Ca Mau
monthly temperature is 25.5oC in January with and the warmest is 28.5oC in
26.500
27.00
27.500
Temp., oC
Tra Vinh
Can Tho
Dong Thap
An Giang
April.
•Increase trend from 2008.25.500
26.00
26.500Long An
Tien Giang
Kien Giang
Soc Trang
25.00
25.500
1998 2000 2002 2004 2006 2008 2010
Year
g
Vinh Long
2. Physical background
Monthly evaporationMonthly evaporation
•The evaporation regime changes over time and
160.00
Monthly Average Evaporation (1988‐2010)
changes over time and space.
•Evaporation is highest in 120.00
140.00
po., m
m
Bac Lieu
Ben Tre
Ca Mau
the months III, IV andV. The highest amounts for these months varies around 100‐
100.00
hly Average
Evap Tra Vinh
Can Tho
Dong Thap
An Giangmonths varies around 100140 mm.
•As soon as the rain starts in 60.00
80.00
Month Long An
Tien Giang
Kien Giang
Soc Trang
months VIII to IX, lower evaporation is reached, from 40‐80 mm.
40.00
1 2 3 4 5 6 7 8 9 10 11 12
Month
g
Vinh Long
40 80 mm.
Hydrogeology2. Physical background
Hydrogeology
Hydrogeological map
2. Physical background
Hydrogeology
There are eight distinct aquifersin the MD:in the MD: 1. Holocene aquifer (qh); 2. Upper Pleistocene aquifer (qp3); 3
3. Upper‐middle Pleistocene aquifer (qp2‐3);
4 Lower Pleistocene aquifer (qp );4. Lower Pleistocene aquifer (qp1); 5. Middle Pliocene aquifer (n2
2); 6. Lower Pliocene aquifer (n2
1); 7. Upper Miocene aquifer (n1
3) 8. Upper‐Middle Miocene aquifer
(n12‐3)
Hydrogeological map
(n1 ).
Hydrogeology
Hydrogeological cross‐section
Hydrogeology
Hydrogeological cross‐section
Hydrogeology
Hydrogeological cross‐section
Upper Pleistocene qp3
Upper‐middle Pleistocene qp2‐3
Lower Pleistocene qp1
Middle Pliocene n22
Lower Pliocene n21
Upper Miocene n13
2. Physical background2. Physical backgroundHydrology•The Mekong Delta river system g yincludes relatively dense network of natural rivers and canals.•Long natural rivers are Tien and gHau, flow to the sea in estuaries via nine river mouths, transfer large amounts of water to the total annual flow of 325 41 billion m3 in Tan Chauflow of 325.41 billion m3 in Tan Chau and 82.43 billion m3 in Chau Doc stations.•Both the Tien river Hau river is•Both the Tien river, Hau river is wide and deep, the average width of about 1000‐1500 m, with an average depth of 10‐20 m.depth of 10 20 m.
2. Physical background2. Physical background
Hydrology•The Vam Co river consists of two branches Vam Co Dong and Vam Co Tay, is derived from Cambodia, flows east through the Mekong Deltaeast through the Mekong Delta•The Cai Lon‐Cai Be are the tidal rivers, derived from the center of the Ca Mau and flows to the sea through gthe Cai Lon river mouth. The estuary is very wide but not deep heart. •The system of canals has been classified into 3 levels, namely of major, primary and secondary canal systems. The system of canals is quite dense having a density of 80‐10dense, having a density of 80 10 m/ha and a total length of 30.000‐40000 km.
3. Legal and institutional framework
Legal Framework
•Constitution 1992 (Amended in 2001)Constitution 1992 (Amended in 2001)
•Water resources law ‐ No.13/2012/QH13
•Government Decree No 179/199/NĐ CP delivered•Government Decree No. 179/199/NĐ‐CP delivered 30/12/1999 on the implementation of water resources law (being amended)law (being amended).
•Secondary regulations on implementation of water resourcesresources.
•Other related Laws ( Land, Fishery, Forest, Dykes, Environment )Environment …)
•Policies and strategies for water sector•State management of Vietnam’s water sector•State management of Vietnam s water sector
Position and Key Dimensions of Water Sector Legislation in Vietnam
Basic Regulation
Constitution 1992
Legislation on Water
Law on Water Resources 2012;
Decree No1992
(Amended in 2001)
Sector in Vietnam
Decree No. 179/1999/ND‐
CP
Basic strategy andprotection, exploitation
prevention, resistance and overcome of
international managemeninspection
andOwnership
Basic investigation
strategy and planning
exploitation and
utilization
any adverse consequences caused by by
water
financeinternational relations
management
and distiputessettlement
MINISTEROrganizational set‐up for water resources
DEPUTY MINISTERS
State management Departments State non-business Units Businesses
management
Land Administration
Environment Administration
Dept of Geology and Minerals of
VN
Dept of Water Resources
International Cooperation Dept
Planning Dept
Science and
National Hydrometeorology Centre
Centre of Water Resources Investigation and Planning
National Remote Sensing Centre
VietNam Natural Resources and Enviroment Corporation
Viet Nam Publishing House of Natural Resources EnvironmentAdministration
Sea and Island Administration
Management
Information Technology Dept
Dept of Hydrometeorology
Technology Dept
Legal Dept
Finance Dept
Em lation and
Centre
Centre for Nursing and Rehabilitation
Natural Resources and Environmet Newspaper
Natural Resources and
Natural Resources, Environment and Cartography
Hydrometeorogical and Enviroment Equipment Joint Stock
CompanyHydrometeorology
and Climate Change
Dept of Survey and Mapping of VN
Emulation and Commedation Dept
Organization and Personnel Dept
Inspectorate
Environmet Magazine
VietNam Enviroment Protection Fund
Institute for Natural Resources and Enviroment
Strategies and Policies
Office
Office of Party Committee of the Ministry
specto ate
Ministry’s representative
Agency in HCMCity
Strategies and Policies
VietNam Institute of Geosciences and Mineral
Resources
Institute of Meteorology, Hydrology and Enviroment
Office of Trade Union of the Ministry
Office Steering Committee 33
S di Offi Vi
y gy
VietNam Institute of Geodesy and Cartography
HaNoi University for Natural Resources and Enviroment
MONREStanding Office Vietnam
National Mekong Committee
Rating Council Office of Mineral Reserves
University of Natural Resources and Enviroment of
HCM city
Central College of Natural Resources and Enviroment
Department of Water Resources Management
DIRECTORY BOAD(DWRM)
DEPAT. OF PLANNING -ADMINISTRATION
DEPARTMENTSDEPARTMENTS CENTERSCENTERS
CENTRE FOR WATER RESOURCES TECHNOLOGY
DEPAT. OF SCIENCE TECHNOLOGY AND
INTERNATIONAL RELATION
RESOURCES TECHNOLOGY
CENTRE FOR WATER RESOURCES
APPRAISEMENT ANDDEPAT. OF LEGAL AND
POLICY ON WATER RESOURCES
DEPAT. OF WATER RESOURCES SURVEY AND
APPRAISEMENT AND CONSULTANCY
CENTRE FOR WATER RESOURCES INFORMATION
AND ECONOMYRESOURCES SURVEY AND INVESTIGATION
B DEPAT. OF WATER RESOURCES PLANNING AND
DEVELOPMENT
N CONO
DEVELOPMENT
OFFICE
CENTRE FOR WATER RESOURCES PLANNING AND INVESTIGATION (CWRPI)
MINISTRY OF NATURAL RESOURCES AND ENVIROMENT
CENTRE FOR WATER RESOURCES PLANNING AND INVESTIGATION
OFFCIE BUREAU FOR PLANNING ANDOFFCIE BUREAU FOR PLANNING AND FINANCING
BUREAU FOR WATER RESOURCES PLANNING
SCIENCE TECHNOLOGY AND INTERNATIONAL COOPERATION
BUREAU FOR SURFACE WATER INVESTIGATION AND
INVENTORY
RESOURCES PLANNINGCOOPERATION
BUREAU FOR GROUNDWATER INVESTIGATION AND
INVENTORY
CENTRE FOR WATER
CENTRE FOR WATER
DIVISION FOR WATER
DIVISION FOR WATER
DIVISION FOR WATER
CENTRE FOR WATER
CENTRE FOR WATER
RESOURCES DATA BASE AND INFORMATION
RESOURCES PLANNING AND INVESTIGATION
CONSULTACY AND SERVICES
RESOURCES PLANNING AND INVESTIGATION FOR THE NORTH
OF VIETNAM
RESOURCES PLANNING AND INVESTIGATION
FOR THE CENTRAL
REGION OF VIETNAM
RESOURCES PLANNING AND INVESTIGATION FOR THE SOUTH
OF VIETNAM
RESOURCES QUALITY
RESOURCES MONITORING
AND FORECAST
DIVISION OF WATER RESOURCES PLANNING AND INVESTIGATION FOR THE SOUTH OF VIETNAM (DWRPIS)INVESTIGATION FOR THE SOUTH OF VIETNAM (DWRPIS)
DIRECTORIAL BOARD
DIRECTOR GENERAL
SUPPORTED SECTIONS PRODUCTION SECTIONS
DIRECTOR GENERAL
FIRST DIRECTOR GENERAL
Administrative Section Subdivision 801
Subdivision 802FIRST DIRECTOR GENERAL
SECOND DIRECTOR
Personnel SectionSubdivision 803
Subdivision 804
GENERAL
THIRD DIRECTOR GENERAL
Technical Section
Planning Section
Subdivision 805
Subdivision 806
Centre for Information andTHIRD DIRECTOR GENERAL Planning Section
Finance and Statistic
Centre for Information and Applied Informatics
Centre for Analysis and Test
Section Centre for Geological Production
4. Problem descriptionsGroundwater depletion
Abs.Elev. of GW level in aquifer qh
4
5
Q003010
Q022010
Q031010
3
m
Q031010
Q07701A
Q07701H
Q104010
Q17701T The average rate
1
2
v. of GW level, m Q17701T
Q199010
Q203010
Q20302T
The average rate of GW reduction is 0.064m/year (1995‐2010)
1
0Abs.Elev
Q204010
Q206010
Q209010
Q211010
(1995 2010)
‐2
‐1Q214010
Q217010
Q219010
Q326010
‐3
Jan‐94 Oct‐96 Jul‐99 Apr‐02 Jan‐05 Oct‐07 Jul‐10
Time
Q326010
Q40101T
Q59801t
4. Problem descriptionsGroundwater depletion
Abs.Elev. of GW level in aquifer qp3
4.000
6.000
2.000Q02202T The average rate
.000
v. of GW level, m Q02702t
Q031020Q17701Z
The average rate of GW reduction is 0.15m/year (1995‐2010)
‐4.000
‐2.000
Abs.Elev Q20302z
Q20402TQ209020
(1995 2010)
‐6.000
Q219020Q40101ZQ40102T
‐8.000
Jan‐94 Oct‐96 Jul‐99 Apr‐02 Jan‐05 Oct‐07 Jul‐10
Time
Q402020Q404020
4. Problem descriptionsGroundwater depletion
Abs.Elev. of GW level in aquifer qp2‐35.000
Q02202Z
Q02702z
.000
m
Q104020
Q177020
Q188020
Q199020 The average rate
‐5.000
v. of GW level, m
Q203040
Q20402z
Q206020
Q209030
of GW reduction is 0.30m/year (1995‐2010)
‐10.000
Abs.Elev Q209030
Q211020
Q21402T
Q217020
‐15.000
Q326020
Q40102Z
Q403020
Q40403T
‐20.000
Jan‐94 Oct‐96 Jul‐99 Apr‐02 Jan‐05 Oct‐07 Jul‐10
Time
Q597030
Q598020
4. Problem descriptionsGroundwater depletion
Abs.Elev. of GW level in aquifer qp1
000
5.000
‐5.000
.000
m
Q02204T
Q027030 The average rate
‐10.000
v. of GW level, m Q031030
Q104030
Q188030
Q211030
of GW reduction is 0.285m/year (1995‐2010)
‐15.000
Abs.Elev
Q21402Z
Q219030
Q326030
Q401030
‐20.000
Q40903A
Q598030
‐25.000
Jan‐94 Oct‐96 Jul‐99 Apr‐02 Jan‐05 Oct‐07 Jul‐10
Time
4. Problem descriptionsGroundwater depletion
Abs.Elev. of GW level in aquifer n22
000
5.000
‐5.000
.000
m
Q02204Z
Q02704T The average rate
‐10.000
v. of GW level, m
Q17704T
Q19904T
Q204040
Q206030
of GW reduction is 0.434 m/year (1995‐2010)
‐15.000
Abs.Elev Q206030
Q21104t
Q214030
Q217030
Q32604T
‐20.000
Q32604T
Q40104T
Q40403Z
Q406040
‐25.000
Jan‐94 Oct‐96 Jul‐99 Apr‐02 Jan‐05 Oct‐07 Jul‐10
Time
Q409040
Q59804T
4. Problem descriptionsGroundwater depletion
5
Abs.Elev.of GW level in aquifer n21
0 Q022050
Q02704z The average rate
‐10
‐5
f GW level, m
Q031040
Q17704Z
Q19904Z
Q20904T
of GW reduction is 0.365 m/year (1995‐2010)
‐15
10
Abs.Elev. of
Q21104Z
Q214040
Q217040
Q219040
‐20
Q
Q32604Z
Q40104Z
Q40404T
Q40404Z‐25
Jan‐94 Oct‐96 Jul‐99 Apr‐02 Jan‐05 Oct‐07 Jul‐10
Time
Q40404Z
Q405050
Q59704T
4. Problem descriptions4. Problem descriptions
Groundwater depletion
Abs.Elev.of GW level in aquifer n13
2.000
4.000
1
The average rate
‐2.000
.000
W level, m Q017050
Q021050
Q027050
of GW reduction is 0.266 m/year (1995‐2010)
‐6 000
‐4.000
Abs.Elev. of GW Q027050
Q20904Z
Q214050
Q219050
‐8.000
6.000Q402040
Q59704Z
‐10.000
Jan‐94 Oct‐96 Jul‐99 Apr‐02 Jan‐05 Oct‐07 Jul‐10
Time
4. Problem descriptionsD i i f d ll iDescriptions of groundwater pollution
4. Problem descriptionsDescriptions of saltwater intrusion
qh aquifer qp3 aquifer
Area of fresh GW (M<1 g/l) = 4398.1km2, A f li GW (M>1 /l)
Area of fresh GW (M<1 g/l) = 10,494.4km2,
Area of saline GW (M>1 g/l) = 35,580.0km2.
, ,Area of saline GW (M>1 g/l) = 28,973.9Km2.
4. Problem descriptionsDescriptions of saltwater intrusion
qp2‐3 aquifer qp1 aquifer
Area of fresh GW (M<1 g/l) = 14,941.0km2.1km2, A f li GW (M>1 /l)
Area of fresh GW (M<1 g/l) = 10,494.4km2,
Area of saline GW (M>1 g/l) = 24,338.1km2.
, ,Area of saline GW (M>1 g/l) = 28,973.9Km2.
4. Problem descriptionsDescriptions of saltwater intrusion
n22 aquifer n2
1 aquifer
Area of fresh GW (M<1 g/l) = 14,013.8 km2, A f li GW (M>1 /l)
Area of fresh GW (M<1 g/l) = 16,268.9 km2,
Area of saline GW (M>1 g/l) = 22,253.4 km2.
, ,Area of saline GW (M>1 g/l) = 18,276.7 Km2.
4. Problem descriptionsDescriptions of saltwater intrusion
n13 aquifer
Area of fresh GW (M<1 g/l) = 10.390,2 km2, A f li GW (M>1 /l)Area of saline GW (M>1 g/l) = 21,169.7 km2.
4 Problem descriptions4. Problem descriptions
• Descriptions of land subsidence
No informationNo information
5 Research questions and objectives5. Research questions and objectives• Research questions and objectives for groundwater depletion
– to define the sustainable limits of groundwater extraction at glocal (aquifer) levels
– to manage total extractions of groundwater within those limits
– to assess the impacts of climate changes and sea level rise on groundwater resurces
5 Research questions and objectives5. Research questions and objectives
R h ti d bj ti f• Research questions and objectives for groundwater pollution
to integrate groundwater considerations into broad– to integrate groundwater considerations into broadsocio‐economic development planning. Groundwaterresource availability and vulnerability to pollution isnot being considered in the socio‐economicdevelopment planning resulting in potentialinvestment in unsustainable developmentinvestment in unsustainable development.
– Groundwater quality protection issues includecontamination of groundwater by land use activities,bore construction and abandonment, salinityintrusion and arsenic liberation.
5 Research questions and objectives5. Research questions and objectives
R h ti d bj ti f lt t i t i• Research questions and objectives for saltwater intrusion
– to monitor the development of fresh‐saline interfaces at local (aquifer) levelslocal (aquifer) levels
– to propose measures to prevent from salt water intrusion
5 Research questions and objectives5. Research questions and objectives
R h i d bj i f l d• Research questions and objectives for land subsidence
– To design, build and operate a land subsidence monitoring network
6. Data availability• Data for mapping groundwater depletion
Classification and delineation of aquifers YesNumber and distribution of groundwater level observation wells in each aquifer YesTi i f d t l l d li YTime series of groundwater level declines YesContour map of natural groundwater levels before development YesContour map of groundwater levels under the development YesContour map of decrease of groundwater levels YesNatural groundwater recharge and induced recharge NoGroundwater abstractions (domestic, industrial and agricultural) x( , g )Groundwater discharges (to rivers, lakes, sea, and downstream) NoChanges of groundwater storage NoImpacts of groundwater depletion NoImpacts of groundwater depletion NoModeling of groundwater depletion No
6. Data availability• Data for mapping groundwater pollution
Classification and delineation of aquifers yesClassification and delineation of aquifers yes
Number and distribution of groundwater quality monitoring wells in each aquifer yes
Sampling for groundwater pollution study yes
Time series of pollutant concentration increase yesContour map of pollutant concentrations Yes
Sources of pollution (point and/or distributed) No
Vulnerability of groundwater to pollution NoGroundwater quality assessment yesGroundwater use YesGroundwater use YesImpacts of groundwater pollution NoModeling of groundwater pollution No
6. Data availability• Data for mapping saltwater intrusion
Classification and delineation of aquifers YesClassification and delineation of aquifers Yes
Number and distribution of groundwater level and quality monitoring wells in each aquifer Yes
Sampling for groundwater salinity study NoTime series of salinity increase YesC t f li it YContour map of salinity YesSources of saltwater No
Fresh/salt water interfaces (determined by geophysical surveys, water samples, and monitoring data) YesImpacts of saltwater intrusion NoModeling of saltwater intrusion YesModeling of saltwater intrusion Yes
6. Data availability
• Data for mapping land subsidence
Classification and delineation of aquifers and aquitards yes
Number and distribution of groundwater level and land subsidence monitoring wells in each aquifer
No
Spatial monitoring of land subsidence No
Time series of accumulated land subsidence No
Contour map of accumulated land subsidence NoNoCauses of land subsidence NoImpacts of land subsidence No
fMeasures for controlling land subsidence NoModeling of land subsidence No
7. Training needs and capacity development
• Number of experts and experiences
• Required training coursesRequired training courses
• Set‐up of groundwater monitoring networks
I t t f d t it i• Instruments for groundwater monitoring
• Software for groundwater modeling
• Construction of groundwater models
• Measures for mitigating groundwater problemsMeasures for mitigating groundwater problems
• Groundwater management and governance
8 Expectations from the project8. Expectations from the project
• How should project seminars and workshops be organized?
• What assistances are required from the project?
• What results are expected from the project?What results are expected from the project?
• What do you want to learn from other countries?
Wh t i d t t h ith th• What experiences do you want to share with other countries?
THANK YOU!THANK YOU!
DIVISION OF WATER RESOURCES PLANNINGDIVISION OF WATER RESOURCES PLANNINGAND INVESTIGATION FOR THE SOUTH OF VIETNAM