environmental impact assessment and environmental … · 2016. 7. 17. · e-243 the socialist...

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THE SOCIALIST REPUBLIC OF VIET NAMMINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT

CENTRAL PROJECT OFFICE

MEKONG DELTA WATER RESOURCES DEVELOPMENT PROJECT

FEASIBILITY STUDY UPDATE

ENVIRONMENTAL IMPACT ASSESSMENTAND

ENVIRONMENTAL ACTION PLAN

ANNEX I

August, 1998

HASKONING B.V. CONSULTING ENGINEERS AND ARCHITECTSin association with

EUROCONSULT and DELFT HYDRAULICS

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The Socialist Republic of VietnamlMARDICPOMekong Delta Water Resources Development Project

6.4.4.3 Electricity ............................... 496.4.5 Cultural, Aesthetic, Historic Features .496.4.6 Agricultural and Production .496.4.7 Household Energy Supply .49

7. DESCRIPTION OF 0 MON-XA No SUB-PROJECT 50

7.1 Rationale for 0 Mon-Xa No Sub-Project .................................................... . . ... 5072 Detailed Sub-project Description . . ................................................. 0 . .... 50

7.2.1 Original Sub-project Concept . . . .. 507.2.2 Current Status of Sub-project Implementation . . . . 50

7.2.2.1 Water Control System .................................................... : .... 507.2.2.2 Changes in Land Use from OM-XN-FS to Current Conditions ._. .....,.,,,,,,,,,,Sr0

7.2.3 Remaining Elements of Sub-project Implernentation .. . .517.2.4 Land Use Scenario for Environmental Review . . . .51

8. IMPACT ASSESSMENT FOR 0 MON-XA No SuB-PROJECT 52

8.1 Detailed Descniption of Expected Environmental bnpacts 528.1.1 Impacts on Physical Resources . . . .52

8.1.1.1 Sub-prect Impacts on Soils . . .... 528.1.1.2 Sub-project Impacts on Salinity in the Sub-Project. . . .528.1.1.3 Sub-project Impacts on Surface Water Hydrlogy ... . ........................ 528.1.1.4 Sub-project Impacts on Surface Water ouaity . . ................................. . _. 548.1.1.5 Sub-project Impacts on Downstream Surface Water Quality . .... ..... 558.1.1.6 Project Impacts on Groundwater Resources . ............................................ _ . . 558.1.1.7Project Imnpacts on Air Quality . . . . ................... . .... . _ . 568.1.1.8 Project Impacts on Canal Bank StbTilty .. .................................... 56

8.1.2 Impacts on Ecological Resources 6.. . .8.1.2.1 Project Impacts on Terrestrial Ecosystms Within the Sub-Project . . . 568. 1.2.2 Project Impacts on Terrestrial Ecosystems Outside the Sub-Project . . .568.1.2.3 Impacts on Aquatic Ecosystems Wfitin the Sub-Project ... ........ 578.1 2A Sub-project Impacts on Aquatic Ecosystems Outside the Sub-Project ...................... 5................... 578.1.2.5 Project Impacts on Protected Areas Within Sub-Projet . . ..... A.............. .... 578.1.2.6 Sub-project Impacs on Downstream Protected Areas ................................................ . ___ 57

8.1.3 Impacts on the Socio-economy . . . .578.1.3.1 Sub-project Impacts on Public Health ...... . .5.................... . _ .. _78. 1.3.2 Impacts on Drinking Water Suppiy Wthin Sub-Project . ............ .................. 5.......... _._._. 588.1.3.3 Project Impacts on Downstream Drinking Water Supply .......................................... _ _. 588.1.3.4 Project Impacts on Fisheries ....................... 588.1.3.5 Project Impacts on Human Setlements, Communities, and lnfrstructure ... 598.1.3.6 Sub-project Impacts on Cultural, Aesthetic, Historic Features . . .598. 1.3.7 Project Impacts on Agricultural Dveopment .. . ............................. 598.1.3.8 Project Impacts on Household Energy Supply ..................................... ... 608.1.3.9 Project Impacts on Transportation and Navigation .... . . . .............................. 60

9. ENViRONMENTAL ACTION PAN FOR 0 MON-XA No SUB-PROJECT 61

9.1 Summary of Environmental Mitigation .......... .................... 6192 Environmental Monitorng ..................... ..... 61

9.2.1 Proposed Expansion of the Surface Water Quality Monitoring System . .619.2.2 Cost Summary for Expanded Water Quality Monitoring Program . .62

10. EXISTING ENVIRONMENT OF THE QUAN Lo PHUNG HIEP SUB-PROJECT 66

w ~~~~10.1 General Deciton_ - -......... se.....____610.2 Physical Resources. ........................

10.2.1 Climate....... .6810.2.2Soils..6810.2.3 Surface Water Hydrology, Salinity, and Addity..69

MDWRDP, Feasibility Study UpdateAnnex I, Environmental Impact Assessment and Environmental Action Plan. August 1998 iii

The Socialist Republic of Vietnam/MARD/CPOMekong Delta Water Resources Development Project

10.2.3.1 Surface Water Hydrology ..................... 6910.2.3.2 River and Canal Network ..................... 6............ ... 6910.2.3.3 Precipitation Regirme ................. . 6910.2.3.4 Mekong River Flows .. 6910.2.3.5 Ocean Tides .. 7010.2.3.6 Current Hydrological Regine of the Sub-project area .7010.2.3.7 Salinity ....................................... 7110.2.3.8 Surface Water Acidity .. 7110.2.3.9 Within Sub-project Surface Water Quality .. 72

10.2.4 Groundwater Resources .. 7210.2.5 Air Quality .. 73

10.3 Ecological Resources .......... .. ......................... .. 73

10.3.1 Land Use and Vegetaton Cover .7310.3.2 Terrestrial Ecosystems Wdhin the Sub-Prject .73

10.3.2.1 Nipa Pam .7310.3.2.2 Use of Terrestrial Ecosystem Resources by Local Households .74

10.3.3 Aquatic Ecosystems Within the Sub-Project .................................. 7410.3.4 Siodiversity Within the Sub-Project .. 7........................... 7410.3.5 Protected Areas Within the Sub-Project .7510.3.6 Ecosystems and Protected Areas Outside the Sub-Prject .75

10.3.6.1 Coastal Wetlands Protecbtion and Develpment Project ...................................................... 7510.3.6.2 Protected Areas Under the National System or' Prtected Areas . .75

IOA- Socio-economac Resources . . .. . ......... .. __7610.4.1 Populabon, Demnography, and Ethnic Compositioi ....................................... 7610.42 Drinking Water Supply Within Sub-Project .7610.4.3 Disease and Public Health ............................... ........ 7710.4.4 Drinking and Domestic Water Supply Outside the Sub-Projec ....................................... 7710.4.5 General Infrastructure and Industry .77

10.4.5.1 Transporttion ..... . . . . .... . . . 7710.4.52 Level of Idustiasa.on.. .................. ... . 7710.4.5.3 Elecity ..... ............. .78

10.4.6 Cultural, Aesthetic, Historic Features . . . . 7810.4.7 Household Energy Supplyu..p ly................................................. 78

11. DEscRIPTION OF QUAN LO PHUNG HIEP SUB-PROJECT 79

11.1 Rationale for QLPH Sub-Proect . ........................ 7911.2 Proposed Water Resources Devebpmen Syst__.........-.. 7911.3 Detailed Sub-project Descripton._ s............. 80

11.3.1 Originl Sub-project Concept ........................ . _ . _. _ . ...... 8011.3.1.1 Primary Sluices for Prevention of Saliny hnrusion Fron South Chin Sea .. ... 8011.3.1.2 Water Supply Canals for Prevention of Salnity intusion from Gulf of Thaland and ForFreshwater Supply .......... _.__. __80-

t1.3.1.3 Secondary Dra..age Canls ......................................................... 8111.3.1.4 On -Farm Water Control System . ......... ..... ..._ ... _1

1 1.32 Current Status of Sub-project Implementation . . . . .81;11.32.1 WaterControlSystem ..................... . ..... _ ._ _ . .... . 8111.32.2 Changes in Land Use from 1991 to Current CondiKtos . .... 81

11.3.3 Remaining Elements of Sub-project Implementation ..... 8211.3.4 Proposed Land Use ..... 82

12. IMPACT ASSESSMENT OF QUAN LO PHUNG HIEP SUB-PROJECT 84

12.1 Detailed Description of Expected Environmental Impacts. 8412.1.1 Impacts on Physical Resources .. 84

12.1.1.1 Project Impacs on Surface Wastr Hydrology . ...................................... 8712.1.12 Project Ipacts on Sols ...................... .... . .. . ...... 8412.1.1.3 Project bnpacs on Wifthin Sub-project Surface Water Qusllty ._._ 812.1.1.4 Sub-project brpacts on Downsren Surface Waer Quality ._ . . . 89 .12.1.1.5 Project Inpacts on Groundwater Resoure .. . 9112.1.1.6 Project kpacts on Air Qualty.--...... . .. .............. . ..12.1.1.7 Project Impab on Canal Bank Stabilty ............................... . _ . ...... 91

12.12 Impacts on Ecological Resources ...... ..................... . .92

MDWRDP, Feasibility Study UpdateAnnex I, Environmental Impact Assessment and Environmental Action Plan, August 1998 iv

The Socialist Republic of Vietnam/MARDICPOMekong Delta Water Resources Development Project

12.1.2.1 Project Impacts on Terrestrial Ecosystems Within Sub-Project .................................................. 9212.1.2.2 Project Impacts on Terrestrial Ecosystems Outside the Sub-Project .......................................... 9212.1.2.3 Project Impacts on Aquatic Ecosystems Within the Sub-Project ................................................ 9312.1.2.4 Sub-project impacts on Aquatic Ecosystems Outside the Sub-Project ....................................... 9312.1.2.5 Impacts on Protected Areas Wthin the Sub-Project ..................................................... 9312.1.2.6 Sub-project impacts on Downsteam Protected Areas ............................................... 93............. 93

12.1.3 Impacts on Socio-economic Resources .9412.1.3.1 Project Impacts on Publir Heath .9412.1.3.2 Project Impacts on Water Supp Wthin the Sub-Project .9412.1.3.3 Project Impacts on Downstream Drinking Water Supply .9512.1.3.4 Project Inpacts on Subsistence Resource Harvesting .9512.1.3.5 Project mpacts on Hunan Settements, Communities, and Infrastructure .9612.1.3.6 Project Impacts on Cultural, Aesthetic, Historic Featues .9612.1.3.7 Project Impacts on Commodity Production .9612.1.3.8 Project Impacts on Household Energy Supply6 912.1.3.9 Project Impacts on Transportation and Navigation .97

1 3. RECOMMENDED ENV1RONMENTAL MANAGEMENT PLAN FOR QUAN LO PHUNG HIEP SUB-PROJECT 98

13.1 Environmental Mitigation Measures ... . . 9813.2 Environmental Moniorng. . . . .98

13.2.1 Proposed Expansion of the Surface Water Quality Monitoring System .................... ............... 9813.2.2 Cost Summary fbr Expanded Water Quality Monitoring Program .......................................... 101

14. INSTITUmONAL ARRANGEMENTS FOR A MDWRDP MONrToRING PROGRAM 103

15. SUPPORTING DOCUMENTATION 104

Soil Classfficaton System ...... ...... .. ..... ............... .. . .. IMain Soil Groups in the QLPH Area ._

MDWRDP, Feasibility Study UpdateAnnex I. Environmental Impact Asssment and Environmental Action Plan. August 1998 V

The Socialist Republic of Vietnam/MARDtCPOMekong Delta Water Resources Development Project

LIST OF TABLES

TABLE 1: SYNOPTIC INFORMATION FOR DISTRICTS, SOUTH MANG THIT SUB-PROJECT._...................._5TAsLE 2: SYNOPTIC SOCIO-ECONOMIC INFORMATION FOR DISTRICTS, SOUTH MANG THIr SUB-

PROJECT . ...... . ............... _....TABLE 3: DISTRIBUTION OF SOIL TYPES, SOUTH MANG THIT SUB-PROJECT .._TABLE 4: INFLOW AND OUTFLOW IN THE DRY SEASON, SOUTH MANG THIT SUB-PROJECT (M3/S)._...8TABLE 5: WATER QUALuTY, DUYEN HAI DISTRICT, JANUARY 1995, DOWNSTREAM OF THE SOUTH

MANG THIrr SUB-PROJECT . ............. .... . _ . . .. _. _ . . .. .10TABLE 6: LAND USE SCENARIOS, SOUTH MANG THIT SUB-PROJECT.._..._ - --- 19TABLE 7: ANNUAL FERTIUSER AND PESTICIDE I HERBICIDE USE: PRESENT, WIHOUT AND WffITH

PROJECT IMPLEMENTATION (ALL SUB-PROJECT AREAS) ...... 27TABLE 8: WATER QUALITY PARAMETERS MEASURED IN THE MEKONG DELTA WATER QUALrTY

MONITORING NETWORK. ....................... ___... . ... . ..... ... 36TABLE 9: RECOMMENDED ENVIRONMENTAL ACTION PLAN, SOUTH MANG THIT SUB-PROJECT. 37TABLE 10: INCREMENTAL COSTS FOR EXPANDED SURFACE WATER QUALITY MONITORING NETWORK,

SOUTH MANG THIT SUB-PROJECT................ ................TABLE II: SYNOPTIC INFORMATION FOR DISTRICTS, 0 MON-XA No SUB-PROJECT ... 43TABLE 12: SYNOPTIC SOCIO-ECONOMIC INFORMATION, 0 MON-XA No SUB-PROJECT ........ ........ . .43TABLE 13: REPRESENTATIVE WATER LEVELS, PEAK OF RAINY SEASON (OCTOBER), 0 MON-XA No ...45TABLE 14: LAND USE SCENARIOS, 0 MON-XA No SUB-PROJECT .................... 5.1....... _1TABLE 15: WATER LEVELS FOR PEAK OF RAINY SEASON (OCTOBER), CURRENT AND FUTURE

CONDmONS, 0 MON-XA No SUB-PROJECT .. .................-............. 54TABLE 16: RECOMMENDED ENVIRONMENTAL ACnON PLAN, 0 MON-XA No SUB_PROJECT ... 63TABLE 17: INCREMENTAL COSTS FOR EXPANDED SURFACE WATER QUALITY MONITORING NETWORK,

0 MON-XA No SU.-PROJECT.. . ....... ................ 64TABLE 18: SYNOPTIC LAND USE INFORMATION (1997), QUAN Lo PHUNG HIEP SUB-PROJECT . 67TABLE 19: SYNOPTIC SOCIO-ECONOFMC INFORMATION, QUAN LO PHUNG HIEP SUB-PROJECT ........ 67TABLE 20: DISTRIBUTION OF ACID SULPHATE SOL (ASS), QUAN Lo PHUNG HIEP SUB-PROJECT (%)69TABLE 21: CHARACTERISTICS OF THE SOUTH CHINA SEA AND GULF OF THAILAND.._._..-._..._._.70TABLE 22: INFLOW AND OUTFLOW IN RAINY AND DRY SEASON, CA MAU PENINSULA (M3lS) ...... ..... _.74TABLE 23: LAND USE (1997), QUAN Lo PHUNG HIEP SUB-PROJECT..-........._......_.....74TABLE 24: ORIGINALLY PROPOSED PRIMARY SLUICES, QUAN LO PHUNG HIEP SUB-PROJECT .. _...80TABLE 25: LAND USE SCENARIOS, QUAN LO PHUNG HIEP, PHASE I AND 11 ............. 82TABLE 26: LAND USE SCENARIOS, BA RINH TA LIEm . .. . .....-. . ...... ...... 83TABLE 27: LAND USE SCENARIOS, TIEP NHAT ............................. . _ 83TABLE 28: INFLOW AND OUTFLOW IN RAINY AND DRY SEASON, CA MAU PENINSULA: 1991, CURRENT

AND AFTER COMPLETION OF PHASE I, Il (M31s) . ........ .... .................... _ . . . ..... _. 88TABLE 29: WATER LEVELS ALONG THE QUAN Lo PHUNG HIEP CANAL IN THE DRY AND RAINY SEASONS86TABLE 30: CHANGES IN WATER LEVELS AT VARIOUS LOCATIONS OUTSIDE THE QUAN Lo PHUNG HIEP

AREA ._.................................�... .96TABLE 31: RECOMMENDED ENVIRONMENTAL ACTION PLAN, QUAN LO PHUNG HIEP SUB-PROJECT .99TABLE 32: INCREMENTAL COSTS FOR EXPANDED SURFACE WATER QUALITY MONITORING NETWORK,

QUAN Lo PHUNG HIEP SUB-PROJECT. ..................... ...... ___ 102

MDWROP, Feasibility Study UpdateAnnex 1. Environmental Impact Assessment and Environmental Action Plan, August 1998 . Vi


LIST OF FIGURESFIGURE 1: RAINFALL FOR THREE MONITORING STATIONS, SOUTH MANG THIT SUB-PROJECT. ...............6FIGURE 2: DISTRIBUTION OF SOIL CLASSES, SOUTH MANG THiT SUB-PROJECT ..................FIGURE3: CURRENTrSRmuToNOFLANDUSE, SOUTH MANG THITSuB-PRojEcT .................... 12FIGURE 4: CHANGE IN LAND USE, 1991 TO 1996, SOUTH MANG THIT SUB-PROJECT.........FIGURE: ENC oZI osmoFPOPUUA4, SOuTH MANG T TSuP E........14FIGURE 6: SUmmARY OFENRoNmrrAL PACTS, SoUH MANGTHTSust oEcT........22FIGURE 7: RAINFALL, CAN THO (1960-1994) ........ ...... . .......-...-. 44FIGURE 8: DeW UnONOFMAINSOLTPES, 0 MON-XA NOSUBW R..ECT .... .................FIGuRE 9: SUMMARY OF ENVIRONMENTAL IMPACTS, 0 MON-XA NO SUB-PROJECTr-...--...--..-...53FIGURE 10: MONTHLY MEAN RAINFALL DATA, QUAN Lo PHUNG HIEP SUB-PROJECT..........................-68FIGURE 1 1: SUMMRY OF ENVIRONMENTAL IMPACTS, QUAN LO PHUNG HIEP SUB"PROJECT ._....85

MOWRDP, Feasibilit Study UpdateAnex I,, Enviromental Impact Assessment and Environmental Action Plan, August 1990 Vii

The Socialist Republic of Vietnam/MARD/CP0Mekong Delta Water Resources Development Project

ACRONYMS AND ABBREVIATIONS

AAS Actual Acid Sulphate SoilsDANIDA Danish Intemational Development AgencyDARD Department of Agriculture and Rural DevelopmentDOSTE Department of Science, Technology and EnvironmentEJA Environmental Impact AssessmentEAP Enrwonmental Action PlanEU European UnionFAO Food and Agricultural OrganisationFPZ Full Protection ZoneFS Feasibility StudyHIH householdHY High yield(ing)IDA Intemational Development AssociationIPM Integrated Pest ManagementkV kilo-VoltMARD Ministry of Agriculture and Rural DevelopmentMDMP Mekong Delta Master PlanMDWRDP Mekong Delta Water Resources Development ProjectMRC Mekong River CommissionNIAPP National Instue for Agricultural Planning and ProjectionPFS Pre-Feasibility StudyGLPH Quan Lo Phung HiepSA Summer Autumn riceSida Swedish Intermational Development AgencySIWRP Sub-institute for Water Resources PlanningUSD United States DollarUSDA United States Department of AgricultureUSEPA United States Environmental Protection AgencyWS Winter Spring rice

MDWRDP, Feasibility Study UpdateAnnex I. Environmental Impact Asseasment and Environmental Action Plan, August 1998 viii


%AN I n Ints knpacts, nifgabon and morr

EXECUTIVE SUMMARY

This report is the Environmental Impact Assessment and associated Environmental ActionPlan for the Mekong Delta Water Resources Development Project (see map, Appendix A)comprising three Sub-projects:

* South Mang Thit;* 0 Mon-Xa No;* Quan Lo Phung.

This EIA was prepared with the configurations of the Sub-Projects as conceived,designed, and described in documents and information available as of May 1998. In thesereviews, the Consultant considered environmental issues compiled from:

(i) a review of the feasibility studies prepared by the MDMP and ESSA;(ii) environmental issues raised in the reports prepared for this FS Update; and(iii) discussions with the IDA Preparation missions.

The World Bank guidelines for the major environmental impacts to be expected fromdrainage and irrigation and agricultural production projects (World Bank 1991) were used.As the basis for the preparation of this report, any applicable national requirements werealso taken into account.

Major social issues were identified as a part of the environmental review, and anassessment made of their importance. For details on these aspects, the reader is referredto the series of other Annexes to the Main report for the FS Update.

Environmental impacts

All three Sub-Projects will have a number of important positive environmental and socio-economic impacts:

- Improvements in surface water hydrology and soil grade for the purposes ofagricultural production;

- Increasing agricultural production; and- Improvements in transportation through the excavation of new canals and

reshaping of existing canals and of rural access roads and bridges;- Improvements in drinking and domestic water quality through the

implementation of a Rural Water Supply and Sanitation component.

South Mang Thit Sub-Project

The South Mang Thit Sub-project is envirornentally feasible. The Sub-project will have anumber of positive impacts on environmental and socio-economic conditions, and thereare no Sub-project activities that are assessed to have significant negative environmentalimpacts that can not be effectively mitigated.

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The environmental issues with respect to the Sub-project are:

li) Increasing surface water and shallow groundwater contamination from biocides andperhaps nutrients from fertiliser application caused by increasing cropping intensity;

(ii) Public health impacts of an estimated 30% increase in pesticide use.(iii) Possible effects of increasing application of biocides and fertilisers on environmental

and socio-economic resources inside and outside the Sub-project area;(iv) Requirements for resettlement and compensation; and(v1 Impediment to water transportation across the major Sub-project sluices.

Sub-project impacts on terrestrial and aquatic biota, and overall biodiversity, both insideand outside the Sub-project area, are expected to be acceptable overall, largely due to thealready impoverished biodiversity in the Sub-project.

Effects of altered hydraulic regimes and land use are expected to have minimal effects onsurface water quarity through the generation of acid and associated constituents inrelatively small areas of acid soils. Special considerations for land use in areas of shallowacid soils is not required.

0 Mon-Xa No Sub-Project

The 0 Mon-Xa No Sub-project is environmentally feasible. It will have a number ofpositive impacts on environmental and socio-economic: conditions.


(i) Increasing surface water and shallow groundwater contamination frorT' nutrientsfrom fertiliser application caused by increasiing cropping intensity, continuedmovement to triple rice cropping,

(ii) Decreasing inputs of natural sources of nutriients because of enhanced floodprotection;

(iii) Loss of 400 to 600 tonnes per year of fish catch as a result of a sluice operationregime that provides flood protection and drainage for rice cultivation. Theestimated annual net income loss to Sub-project households is about USD1 50,000;

(iv) Requirements for resettlement and compensation; and(v) Impediments to water transportation across the major Sub-project sluices.

Effects of altered hydraulic regimes in canal systems and land use are expected to haveminimal effects on surface water quality through the generation of acid and associatedconstituents in the areas of mainly moderate and slight acid soils. Special land useconsiderations in areas of shallow acid soils are not required.

Quan Lo Phung Hiep Sub-project

The Quan Lo Phung Hiep Sub-project is environmentally feasible. It will have a number ofpositive impacts on environmental and socio-econornic condritons. There are no Sub-project activities that are assessed to have significant environmental impacts that can notbe effectively mitigated.

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(i) Increasing surface water and shallow groundwater contamination from biocides andperhaps nutrients from fertiliser application caused by increasing cropping intensity;

vii) Possible effects of increasing application of biocides and fertilisers on environmentaland socio-economic resources inside and outside the Sub-project area.

(iii) Requirements for resettlement and compensation; and* (iv) Impediment to water transportation across the major Sub-project sluices.

Environmental Action Plan

The proposed Environmental Action Plan for the MDWRDP contains two components:recommendations for environmental mitigation and recommendations for environmentalmonitoring.

Environmental Mitigation

The recommended environmental mitigation activities common to all Sub-projects are:

(i) continuation of education on IPM techniques for rice cultivation and farm workersafety in pesticide and herbicide application through provincial Plant Protection Sub-departments. Experience in applying [PM techniques in the Mekong Delta showsdecreases of the number of pesticide applications to over 80%, and increases inpaddy production of about 0.7 tonne/ha/year. Hence, a successful IPM programmecan negate the otherwise expected negative impacts.

Iii) sluice operation for flushing of the water control systems when water qualitydeteriorates. Depending on the Sub-project layouts and sluice configuration,flushing can generally be appried in the dry season by letting fresh water in at hightide and draining it out through the downstream sluices during low tide.

(iii) implementation of a Rural Water Supply and Sanitation component under theMDWRDP and other rural development programmes sponsored by GOV and

- donors;(iv) implementation of the Resettlement Action Plan for project affected people;(v) provision of boat lifts and transhipment facilities near major project sluices to

alleviate impediments to navigation, as integrated in project design; and(vi) canal excavation and disposal of spoil soil would have to follow specific

methods to minimize release of acids into fields, depending on the localconditions and the severity of the acid sulphate soils.

Point (iii) above is not environmental mitigation that would be required because ofnegative impacts of the Project. It would considerably improve living conditions for ruralhouseholds; it is therefore included into the Project.

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The Socialist Republic of VietnamIMARDICPOMekong Delta Water Resources Development Project

Environmental Monitoring

The proposed environmental monitoring plan is an expansion of the existingSurface Water Quality Monitoring Network. Thirty additional surface water qualitymonitoring stations are proposed. Monitoring would consist of basic surface waterquality parameters, pesticides, and bacteria and coliform. Incremental annualoperating costs are estimated to be USD157,000.

A fisheries survey (USD 90,000) is proposed, especially focussing on the 0 Mon-Xa No area where it will be interesting to follow what the effects of providing fullflood protection would be on the natural species composition, reproduction, catchetc. and to monitor how the anticipated alternatives would develop.

A study on rice-fish farming systems (USD 60,000), which seems to be promising.The study would build on recent research and extension work on rice-fish farmingsystems {Annex VI).

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The Socialist Republic of Vietnam/MARDlCPOMekong Delta Water Resources Development Project

1. INTRODUCTION AND BACKGROUND

This report is the Environmental Impact Assessment (EIA) and associated EnvironmentalAction Plan (EAP) for the Mekong Delta Water Resources Development Project. It isproduced as part of Feasibility Study (FS) updates for three Sub-Projects in the MekongDelta in preparation for IDA financing:

* South Mang Thit, (SMT)* 0 Mon-Xa No, (OM-XN), and* Quan Lo Phung Hiep, (QLPH)

1.1 Oveal Objectives of the EIA-EAP

The objectives of this environmental review are to:

(i) Review all environmental reports available with the Ministry of Agriculture and RuralDevelopment agencies in Viet Nam, especially paying attention to the effects ofacidification, water pollution, salt intrusion, and water quality; and

(ii) Conduct an Environmental Impact Assessment and prepare an EnvironmentalAction Plan for the Project.

1.2 Genral Approach to the EIA

In this review, social issues are identified as a part of the EIA, and an assessment is madeof their importance. For a further treatment on these aspects, the reader is referred to theother Annexes of the Main Report:

Annex II: Resettlement Action Plan;Annex IV: Groundwater and Rural Water Supply and Sanitation;Annex V: Soils and Agronomy; andAnnex VI: Fisheries and Aquaculture.

This EIA-EAP is based on the environmental issues raised:

li) in the feasibility studies prepared by the MDMP Project for SMT (HEC-2 - NEDECO,1994) and OM-XN (SIWRP - NEDECO, 1994) and the pre-feasibility study preparedfor QLPH (SIWRP - HEC-2 - ESSA 1992);

(ii) in the Social and Environmental Study Update for the three Sub-projects, preparedby the SIWRP in preparation of this TA (September-October 1997);

(iii) by the IDA team during their various missions to the Viet Nam to discuss projectpreparation with MARD/CPO and the TA team in preparation of the MDWRDP; and

(iv) in the Inception Report and in the Interim Report for this FS Update, and thecomments received thereupon.

The World Bank guidelines for the major environmental impacts to be expected fromdrainage and irrigation and agricultural production projects (World Bank 1991) were used.The methodology applied in preparing the EIA and EAP is given in Appendix D.

Three reports containing the draft EIA and associated EAP for each of the sub-projectswere prepared in November 1997 and were reported as annexes to the Interim Report ofDecember 1997. This final document incorporates reviews and comments made by IDA

MDWRDP, Feasibility Study UpdateAnnex I, Environmental Impact Assessment and Environmental Action Plan, August 19981

The Socialist Republic of Vietnam/MARDICPOMekong Delta Water Resources Development Project

staff and CPO, and integrates the separate documents into a single EIA for the entireProject.

The environmental reviews for the separate Sub-Proiects, however, can still be treated inthis document as independent assessments.

1.3 Outline of this Report

This report consists of three major sections; each section is devoted to one of the Sub-projects. The general format for each Sub-project is as follows:

* Description of the Exsting Envronment. T his is synthesised from availableinformation on the Sub-project area and field visits, supplemented by the relevantSocial and Environmental Study Update report (SIWRP), information from similarlocations in the Mekong Delta if relevant, and interviews with scientists andplanners working in national and provincial institutions;

* Project Descrption upon which the EIA was conducted. It is a synthesis ofinformation contained in the FS, supplemented by updated information obtainedduring the course of the FS update. It describes, using the best availableinformation, what engineering works have been constructed and what land usechanges have occurred since the completion of the FS, and what is being proposedfor completion of the Sub-project;

* ImpactAssessmnent, an evaluation of the environmental impacts of the Sub-project;* Environmental Action Plan for the Sub-project, consisting of mitigation and

monitoring requirements as well as arrangemfents for implementation.

The main report is supplemented by a series of appendices.

Appendix A: Maps

Appendix B: Soils of the Mekong River Delta Description and Guidelines for Use

Appendix C: Trends in Surface Water Quality in the Quan Lo Phung Hiep Area

Appendix D: Impact Assessment Methodology

MDWRDP, Feasibility Stidy UpdateAnnex 1, Environmental Impact Assessment and Environmental Action Plan, August 1998 2


SOUTH MANG THIT SUB-PROJECT

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The Socialist Republic of Vietnam/MARDfCPOMekong Delta Water Resources Development Project

2. EXISTING ENVIRONMENT OF THE SOUTH MANG THIT SUB-PROJECT

2.1 General Description

The South Mang Thit (SMT) Sub-project was one of the five high. priority projects thatwere selected for feasibility studies {FS) as a result of the preliminary evaluation in the firstphase of the MDMP (NEDECO 1990-1994). The main objective of the FS was todetermine the optimal plan for sustainable and integrated use of the resources in the Sub-project area in order to increase the productivity and to improve the living conditions ofthe local people.

The SMT Sub-project as proposed in the FS is consistent with the development strategyrecommended in the MDMP, October 1993. The Sub-project.consists of about 225,680ha of the Mekong Delta and includes most of Tra Vinh Province and part of Vinh LongProvince. Tra Vinh province is one of the poorest in Viet Nam, with per capita income andliving standards well below the national average. The area of specific concern in thisEnvironmental Review is known as Regions A, B and C in the original FS. The Sub-projectarea includes nine districts'.

The SMT area is a coastal plain with low, flat elevation ranging from 0.4 to 1 m. The areacontains two specific topographical regions. The region to the north of inter-provincialRoad No. 36 with low and flat topography, and the region to the south of that roadconsisting mainly of flat lands intersected by higher elevation sandy ridges.

About 1,131,000 (1996) people live in the SMT area. These people are mostly Kinh,although almost one-quarter is Khmer. Land is mainly used for agriculture, and thereremains only a small amount of unused land.

Synoptic information for the Sub-project area is presented in Table 1 and Table 2.

A very small portion of Cau Ngang District is in the coastal Region D. For the purposes of thisEnvironmental Review, however, it was assumed that all of Cau Ngang District lies withinRegions B and C of the Sub-project. This made the tasks of data assimilation, review, andpresentation easier and more efficient than if the District had been allocated more exactly tothe two Regions. The conclusions reached in this review would be the same under eitherapproach.

MDWRDP, Feasibility Study UpdateAnnex 1, Environmental Impact Assessment and Environmental Action Plan, August 1998* 4

The Socialist Republic of Vietnam/MARD/CPOMekong Delta Water Resources Development.Project

rak 1:ShtvmfwAvbkr 4 & 7?ia6PrhR

Gross Area Population Agr. Area 3 Rice 2 Rice 1 Rice Other Agr. Fish Forest other(ha) (ha)

SMT 225.682 131,247 171.837 33,282 47,306 61.536 29,713 2.352 1,211 50,282

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AW Etdwic Composidon (%tArea Populatn Total Ave. HH Agr. Lid Land/HH % HH With Fresh(hal No. HH Size No. Agr. Mi (ha) (ha) Khnh KhArp HOJ Otheas Water

ubpolect 225,682 1,131,247 221,168 5.21 180,528 138,260 1.07 75.8 22.9 1.3 0.0 38.1TM On 26,531 159,797 25,614 5.30 19,607 17.371 0.89 92.5 7.0 0.5 0.0 30.3VtuiLMm 22,489 135,064 30,750 5.47 23,39 18.914 0.80 94.0 5.8 0.4 0.0 65.3Tra Vumh 4,843 70,284 13,887 5.06 1,858 2,283 1.23 80.5 10.1 9.3 0.1 49.7Cong Lon 28,905 162,737 29,750 5.47 22,774 28,101 1.15 94.0 5.6 OA 0.0 21.4CouKe 24,118 125,010 23,595 5.30 18,062 22,141 1.23 70.9 28.6 0.5 0.0 73.6VWeucn 22,110 110,651 21,488 5.15 18,448 19,820 1.21 70.3 28.1 1.5 0.0 51.2ChauT &nh 37, 762 131,559 24,621 5.15 18,848 23,978 1.27 84.8 34.6 06. 0.0 9.87MCu 26,656 11i,991 25,732 5.74 19,697 23,942 1,22 42.1 56.8 1.3 0.1 6.4

Cau Ngan 32,268 106,172 25,732 5.12 19.097 15,291 . 0.B3 83.8 35.5 0.7 0.0 48.5

' This Information was not available at the District level, but was only available for the entire Sub-project. The proportion of the total households In each districtthat were assigned to be agricultural was therefore set as the Project-wide proportion.

MDWROP, Feasibility Study UpdateAnnex I, Environmental Impact Assessment and Environmental Action Plan, August 1998 5


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2.2 Physical Resources

2.2.1 Climate

Two distinct seasons occur in the SMT area: the rainy (or wet) season from Mayto November; and the dry season from November to April. Roughly 90% of theannual rainfall is concentrated in the rainy season and provides a mean annualrainfall of about 1,400 mm (1977-1997) (Figure 1).

Dry spells lasting up to 30 days in some years may occur in June and July.Temperature and radiation conditions are excellent for producing tropical foodcrops. The fluctuation of the mean monthly temperature is less than 3 degrees(25.4-28.2'C). Relative humidity usually exceeds 80%. Potential evapo-transpiration is about 140 mm per month.

2.2.2 Soils

There are three main different soil types in the SMT area (Table 3): Sandy soils (6%),Alluvial soils (61%), and Acid Sulphate soils (33%). The FS of 1994 indicates that about12,000 ha are underlain with shallow acid soils fi.e. with an acid generating layer lessthan 50 cm deep), representing about 5.4% of the total Sub-project area (Figure 2).

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The Socialist Republic of VietnamnMARDlCPOMekong Delta Water Resources Development Project

Tdhbb rliratslp.. ScaEAfre 1Mbpqsc

Sol Types Area (ha)Sandy SoilSandy depression sods 284Sandy ridge soils 15,240AAk/l SoibNon active Ailuvial sis 2,349Acive Aluvwil soIs 8,892Recaetly actnve Alluvial sois 26,125Non affected Aluvial sois on sandy ridges 45,047Sightly affected Aluvial sois on sandy ridges 11,235Modoetely affected Alluvial sods on sandy ridges 908Slightly saline Akuial soils 35,931Modeately sain Alluvial soils 21,722Strongly saline Auvial soils 6,057Acdd Su42haft SalkNon-affected sain I potentially acid sulphate soils 41,210Sightly-ffected saie/ potentially acid suihte sods 7,575Moderately affected saine otentiap y acid siphat sois 3,286StroV affected saine Ipotenti acid suiphe sois 15,520Non affected salW acdve acid sdphate soils 2,787Sightly affected s actve aid sdphte sois 13,330Moderately affect saire acive acid siphate sois 411

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2.2.3 Surface Water Hydrology, Salinity, and Acidity

22.3.1 Suface WawHy&WOgy

Four main factors influence the surface water hydrology of the Sub-Project: precipitation,river flows, ocean tides, and canal flows. A summary of current inflows and outflows forSMT (dry season) are provided in Table 4.

MDWRDP, Feasibility Study UpdateAnnex I, Environmental Impact Assessmnent and Environmental Action Plan, August 1998 7


Parmeter Before 1993 Current ConditonsINFLOW:

Predpiaion 0 0From Bassac River 14 18From Co Chien River 18 26From Mang Thit River 21 23FsomOcean 60 63

TOTAL INFLOW 113 130

OUTFLOW:

To Bassac River 4 4To Co Chbn ver 4 5To Mang Thit River 0 0ToOcean 65 66

TOTAL OUTFLOW 73 75

INFLOW imnus OUTFLOW: 40 55

River Flows - The Mekong River is the only practical source of fresh water for irrigationduring the -dry season. Flows into and out of the Tonle Sap Lake in Cambodia influencethe discharge hydrograph of the Mekong River significantly. December and Januaryaverage flows approximately double downstream of Phnom Penh compared withupstream, because of the water release from the Tonle Sap Lake. In February, thedischarge downstream of Phnom Penh is about 4,300 m3 /s compared with about2,700 m3/s upstream. Approximately 50% of the flows at Phnom Penh enter the SouthChina Sea via the Bassac River. The Bassac, the Co Chien, and Mang Thit riers (theMang Thit River connects to the Bassac and Co Chien rivers) are the sources of freshwater during the dry season for the Sub-project.

Canal Network - Many main canals, primary canals, and creeks with a total length of 875km connect with the main rivers. Together with about 2,000 km of secondary canals andsome 10,000 km of on-farm canals, they provide a dense overall canal network. Thesurface water network serves both for drainage and for irrigation water supply.

Precipitation - The major feature of the precipitation regime is that most of the annualprecipitation falls during a seven month period, from May to November. Rainfall isextremely low from December to April (Figure 1).

Tides - Ocean tides with amplitude of up to 3.00 m have a strong influence on the Sub-project area. Along the Mang Thit River, the tidal amplitude is still up to 2.20 m.

Hydrological conditions determining the rationale for the SMT Sub-project are:

(i} salinity intrusion;(ii) water-ogging;(iii) inundation; and(iv) a shortage of fresh water for agriculture in the dry season.

These constraints are caused by the insufficient capacity of the existing canal networkand by a lack of sufficient water control structures.

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The Socialist Republic of vietnam/MARD/CPOMekong Delta Water Resources Development Project

2.23.2 Sainy

Situation Prior to Initiation of Sub-project: In the absence of sluices to prevent the inflowof saline water, the tide penetrated deep into the area. It brought saline water in thecanals and creeks that would be the source of irrigation water, causing a too high salinityfor irrigated agriculture in the dry season.

Existing Situaton: Some of the engineering works idlentified in the SMT-FS have alreadybeen constructed (Section 3.2.2). Salinity intrusion in the Sub-project area reducedgreatly, although not to the point that irrigated agriculture in the dry season can beundertaken throughout the entire Sub-project area.

223.3 Aidety

In the Sub-Project:

(i) there are no long term surface water quality monitoring stations maintained by theSIWRP under its Water Quality Monitoring Network;

{ii) there are no water quality monitoring stations in the national EnvironmentalMonitoring system, maintained by the National Environment Agency of Viet Nam;and

(iii) till date, only one surface water quality campaign has been conducted (by RIA-2) asa part of the SMT-FS under the MDMP Project (1992).

ft is likely that the surface water quality in the area is similar to other parts of the MekongDelta. Water is contaminated by sewage, is largely eutrophic, and it can be assumed thatits quality has not substantially changed since the preparation of the SMT-FS3. Thedevelopment of the area since the preparation of the SMT-FS, construction of sluices andcanal excavation, has reduced the area effected by saline/brackish water and hasimproved drainage conditions. Hence, water quality has possibly inproved to some extentin both seasons.

There are acid soils in the area, but there are different descriptions of the patterns of thisacidity.

The SMT Update report states tat: "Special attention is given to the problem of acidwater in the South Mang Thit. At its eastern side, water quality in the rivers and canaisappears relatively favourable in terms of acidity, the pH varies from about 6.5 to over 8,but is normally around 7-7.5. In contrast, at its western side, distinct seasonal acidityinfluences occur. During the early part of the rainy season, the pH drops from normalvalues (6-7) to below 4 and under the influence of rain water it is flushed (leached) fromthe strongly acid sulphate soils."

The SMT-FS, however, states that: min areas adjacent to acid soils, surface watermay seasonally become slightly acid."

A soil map generated for the entire Mekong Delta as a part of the MDMP Project (seemap, Appendix A) suggests that acid water is not an issue for the Sub-project area.

3 Coliform levels were reported to be as high as 480,000 MPNilOO ml. and E.coli levels werefrom 4 to 100,000 MPN/1 00 mlJ (based on 14 samples).



Although it is not possible to demonstrate the spatial and temporal distribution of acidgeneration and transport in the Sub-project area, continued improvements in the watercontrol system since the early nineties have already enhanced the drainage and flushingconditions. It is experienced in the Ca Mau Peninsula, where acid sulphate soils are muchmore widespread and where land reclamation took place at massive scale over the pastten years, that improved drainage and flushing gradually leads to an improvement insurface water quality. This offsets the impact of acid release from the soil after oxidationin the dry season (see Appendix C).

The surface water downstream of the Sub-project area, in Duyen Hai District(Region D of the original SMT-FS) demonstrates the influence of marine waters(Table 5) on the surface water quality. The limited sample set generally indicatesgood quality water that meets most of Viet Nam's coastal water qualitystandards".5.

&ab KWwVAy MW iDsf rzWy I=ob~of Siwe nduA& 7M&Ap9sd

No. pH SS CL7 NO, NH, Tot Fe SOD.1 8.0 330 4,490 0.04 0.13 3.90 162 8.4 115 8.750 0.06 0.10 3.44 123 8.0 180 8,070 0.09 0.20 3.66 184 8.3 20 7,180 0.05 0.11 0.97 165 8.0 130 9,650 0.10 0.15 0.82 22

All datea except pH are in mg/l

2.2.4 Groundwater Resources

The only available source of information on groundwater resources is from the MDMPProject (Working Paper no. 2) and in the SMT FS the following conclusions were reached:

li) the groundwater quality in the norh-eastem portion of the SMT area is generallypoor;

'ii) the groundwater in the lower two thirds of the SMT area appears to be generally ingood supply;

iii). in the central part of the area, the MDMP Thematic Study indicates thatgroundwater is available only at depths of more than 350m. This is partly bome outby the SMT FS that indicates that the central part is brackish. This area is alsocovered by a shallow aquifer with water of inconsistent quantity and quality. Thisshallow aquifer is not even mentioned in the SMT FS as a useful source of water,even for irrigation purposes; and

(iv) the proposed major source of freshwater supply, the Pleistocene Aquifer wasalready showing signs of bacterial contamination at some locations (see Page 24 ofthe groundwater supply annex of the SMT FS). The SMT FS containsrecommendations for treatment of groundwater before use which are alsoincorporated in the rural water supply and sanitation component of this MDWRDPproject.

* MOSTE, 1995, Provisional water quality standards.' The exceptions are iron and suspended solids, which may be an artifact of the sampling

locations. It appears from the original data that some of the sampling points were located invery small canals, which are unusually turbid. High total iron levels are usually associated withhigh suspended solids because of the high iron adsorbed onto the suspended sediments.This may need to be figured into the implmentation of the Rural Water Supply and SanitationComponent of the Sub-project.

MDWRDP, Feasibility Study UpdateAnnex I. Environmental Impact As essment and Environmental Action Plan, August 1998 10


2.2.5 Air Quality

As is the case with surface water quality, none of the air quality monitoring stations inthe national Environmental Monitoring system maintained by the National EnvironmentAgency of Viet Nam are located in or near the Sub-project area. Therefore, there are nolong-term records of air quality from the study area.

Notwithstanding this lack of information, air quality is generally very good. Tra Vinh is themajor urban centre within the area, it is still relatively non-industrialised, and there are nomajor sources of air pollutants to affect air quality either locally or over the entire Sub-project area.

2.3 Ecological Resources

2.3.1 Land Use and Vegetation Cover

Figure 3 contains the land use in the Sub-Project in 1997. The data presented are basedon figures provided by the Provinces and have been adjusted for the area within the Sub-project boundary. The Sub-project is dominated by agriculture, with about 80% of theland devoted to agricultural production; most of this is rice agriculture. Vegetation cover iscurrently very limited, with only about 1 % of the Sub-project designated as Forest. Thereis also vegetation in the form of Nipa palm in canals (Section 2.3.2), as well as in theform of scattered trees planted around landholdings for environmental protection and forfuelwood supply.

Land use has changed dramatically since the SMTArS was completed (Figure 4). Theimportant changes are:

6i) an increase in the area of triple rice cropping, which replaced double and single ricecropping. Much of this has occurred in Region A and B; and

(ii) a decrease in .Other* land, indicating bringing fallow land under agriculturalcuttivation.

2.3.2 Terrestrial Ecosystems

There are no intact terrestrial ecosystems remaining wifin the Sub-Project7. Practically allthe land is in use for agricultural production, human setdements, or open water in theform of canals. There are about 1,221 ha of forested land (Table 1). This area is in factlocated in Region D, just at the boundary of the Sub-project area and is part of theCoastal Wetlands Protection and Development Project (Section 2.3.5).

2.3.21 NWpa Pab,

Salinity control sluices have altered the salinity regime in the Sub-project. This already hadan impact on Nipa palm, estimated at the time the SMT-FS was prepared to occupyabout 4,200 ha. Quantification of the reduction in Nipa palm was not possible.

7 This confirms a similar assessment made in the Environmental Impact Assessment to the FSINEDECO 1994).

MDWR3P, Feasibility Study UpdateAnnex I, Environmental Impact Assessment and Environmental Action Plan, August 1998 11


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MDWRDP, Feasibility Study UpdateAnnex I, Environmental Impact Assessrnent and Environmental Action Plan, August 1998 12


23.22 Use of Ten'estdal Ecosystem Resoures by Local Households

Residents of the Sub-project area are likely similar to residents in other parts of the Deltaand rely on terrestrial ecosystems as supplemental source of off-farm or non-farmbenefits (see for example, GEC Ltd., 1997). Terrestrial biota that is captured may be usedfor domestic, subsistence purposes, or may be sold to local markets. Levels of use ofterrestrial resources in the Sub-project area are likely to be lower than in other parts of theDelta (such as U Minh in the Ca Mau Peninsula) because of the generally more degradedand impoverished terrestrial ecosystems in the Sub-project.

2.3.3 Aquatic Ecosystems

With the construction and enlargement of canals, the surface area of open water hasincreased in recent times. This has created new areas for fish within the area.

Due to already completed sluices, which prevent saline water intrusion, the fish speciescomposition is changing from a composition that fluctuated between freshwater to salinewater species to predominantly freshwater species throughout the year.

2.3.4 Biodiversity and protected areas

The Sub-project area contains few biodiversity resources, because of the almost completeabsence of natural terrestrial ecosystems.

There are no areas that are either part of Viet Nam's existing or proposed national systemof protected areas. In addition, the provinces do not maintain protected areas witin theSub-project area.

2.3.5 Downstream Ecosystems and Protected Areas

The coastal areas of Tra Vinh Province contain substantial mangrove ecosystems. Theseareas have been identified in the Viet Nam National Environmental Action Plan (WorldBank 1995) as priority ecosystems for sustainable management and protection. Tnisecosystem is degraded, due to land conversion for shrimp aquaculture and cutting forfuelwood.The MARD/World Bank Coastal Wetlands'Protection and Development Project is a majorinvestment project along the entire marine coastline of four provinces in the Mekong Deltaincluding Tra Vinh. One component consists of a Full Protecton Zone (FPZ) along thecoast of Region D. Investment costs for Tra Vinh Province were estimated to be aboutUSD 4 million (GEC Ltd. 1996).

2.4 Socio-conomy

2.4.1 Population, Demography, and Ethnic Compositon

The Sub-project contains a young, rapidly growing, almost exclusively nrral, already densepopulation of about 1,131,000 persons. Population gmwth rate since the FS has beenabout 2.3% per year.

The predominantly rural population (save for Tra Vinh town and the district towns) isdispersed, but due to inundation as weR as requirements for communication and

MDWRDP, Feasibility Study UpdateAnnex 1, Environmental Impact Assesment and Environmental Action Plan, August 1998 13


transportation, the population is unevenly distributed. It is concentrated on natural levees,along the banks of canals and rivers, and beside roads. Most farm families live in smallsettlements situated at the intersections or along the banks of the canals and rivers.

The population of the Sub-project area is 75% Kinh, 23% Khmer, and slightly more than1 % Hoa. There is considerable variation in the ethnic composition among the districts.Almost 60% of the population of Tra Cu District, is Khmer, while more than 90% of thepopulation of Vung Uem and Cang Long Districts is Kinh (Figure 5).

QuThrt CU

T mu Ca C i b~~~ C I __

Tm onVU'w I t I I II I I_

.~~~~ -

- MO MO Ia0 S10 l10 0D D MO "MO

791tI 6 Edhri caoSpow of popubftm SouSh M&Wx 7hft &Ab-

Household size in the Sub-project area is about 5.2 persons, and ranges from s.'ightlymore than 5 in Tra Vinh to 5.74 persons in Tra Cu (Figure 5). Arable land per householdaverages 1.07 ha, -and varies very iittle throughout the Sub-project area. These figuresmean that arable land per person averages slightly more than 2,000 ml.

2.4.2 Driinkg Water Supply Wthin the Sub-Project

Currently, about 50% of the Sub-project population has access to freshwater fromgroundwater wells, a considerable increase from an estimated 25% in 1992.

This percentage varies greatl fromdistrict to district. In two districts (Chau Thanh andTra Cu), almost no household has access to secure freshwater, while in Cau Ke Districtmore than 3 out of 4 households has a secure freshwater supply.

2.4.3 Disease and Public Health

The Subproject area experiences most of the well-known tropical diseases, namelymFlaria, Dengue fever, and encephalitis, as well as diseases such as tuberculosis andcholera. Basiterial corTtarination in surface water and the use of surface water by ahighproportion of the population means that waterlome diseases of bacterial origin areprevalert. We were not able to obtain updated details on disease and public health for the

MDWRDP, Feasibility Study UpdateAnngx o, unvironmental Impact Assessment and Environmntal Actidon Plan, August 1998 14


Sub-project. The findings on disease prevalence and public health contained in the FSlikely still hold, because:

(i) not all the population has access to clean drinking water;(ii) surface water is extremely contaminated; and(iii) developments that would have caused the surface water quality to improve, like

construction of sluices and canals, may not yet have a significant impact.

2.4.4 Downstream Water Supply

Drinking and domestic water supply downstream of the Sub-project area is in a bettercondition. About 65% of the residents of Duyen Hai District already has access tofreshwater for drinking and domestic use (information from the SMT Update study). Thisis largely due to UNICEF groundwater well construction activities, as well as an EU-funded micro-credit project in the coastal zone of Tra Vinh province (GEC Ltd. 1996).

2.4.5 General Infrastructure and Industry

2A.&1 Transportaion

Navigation - The main navigation takes place along the main channels of the Mang Thit,Co Chien, and Bassac Rivers. The channels can accommodate ships with a capacity ofover 1,000 tonnes. Large ships usually pass the Bassac River mouth en-route to the CanTho port and upstream up to Phnom Penh. In the recent past, several canals wereexcavated for navigation, irrigation, and drainage, including the Tra Ngoa - Thong NhatfTong Ton, My Van, Bung Truong - Ngai Chanh, and February 3d.

Roads - Compared to other provinces of the Mekong Delta, the road network in VinhLong and Tra Vinh Province is quite well developed. There are 650 km of roads of allstandards (except rural roads). The National Road No. 53 connects Vinh Long town to TraVinh town; some inter-provincial roads link the districts and small towns with Tra Vmhtown.

.4.5.2 Level of I AIIAao

The level of industrialisation in Vinh Long and Tra Vinh provinces is extremely low. Onlyabout 8% of the provincial GDP comes from the secondary sector. There are no largeindustrial factories or enterprises, and the most recent foreign investmrent statistics forTra Vinh Province (mid-November, 1997) indicate very low levels of industrial investment.The enterprises engaged in industry are mainly ice lproduction, rice milling, and smallscale, outdated sugar processing factories. A new large capacity sugar mill to beconstructed in 1998/1999 would handle the sugarcane production of an area of5,000 ha.

2.4.&3 .eldt

Although a 65 kV electricity grid has been established to all the districts in the SMT area,this system supplies only the district capitals. The 15 kV electricity grid links Tra Vinhtown to some of the Sub-project villages but not all of the rural population has access toelectricity. The total number of households with electricity is estimated at approximately10%.



2.4.6 Cultural, Aesthetic, Historic Features

There are no cultural, aesthetic, or historic features in the Sub-project area at risk byworks to be constructed for the Sub-project.

2.4.7 Agricultural Production

In 1997 the Sub-project area produced about 0.96 million tonnes of paddy. This is a 25%increase since 1991, and can be attributed to the increasing area of triple rice and doublerice cropping. In addition, there has been some increase in diversification of cropsproduced; particulariy maize is grown on small plots in the northem part of the Sub-project.

2.4.8 Household Energy Supply

Trees are used for fuelwood, house construction, fumiture, and fruit cultivation. Very littlenatural forest remains save for some small pockets throughout the Sub-project.

Fuelwood is extremely important throughout all of Viet Nam. It comprises about 90% ofthe domestic energy consumption at the national level. The World Bank (1995) identifiedthe Mekong Delta as being a deficient region with respect to fuelwood supply. Duyet(1991) estimated that requirements are 0.1 m3 per capita per year. NEDECO (1991)estimates that this should increase to 0.2 m 3 by the year 2000. For the Sub-project, thisis equivalent to a requirement of between 27,000 m3 and 44,000 m3 fuelwood atpresent. The SMT Update mentions that there have been extensive scattered treeplanting programs throughout the Sub-project. This has to continue to meet futurerequirements.

MDWRDP, Feasibility Study UpdateAnnex 1, Environmental Impact Asessment and Environmental Action Plan, August 1998 16

The Socialist Republic of VietnamIMARDICPOMekong Delta Water Resources Development Project

3. DESCRIPTION OF SOUTH MANG THIT SUB-PROJECT

3.1 Ratonale for South Mang Thit Sub-Project

The main issues that formed the rationale for the South Mang Thit Sub-project were:

(i) salinity intrusion;(ii) water-logging;(iii) inundation; and(iv) shortage of fresh water for agrculture in the dry season.

These constraints are caused by the insufficient capacity of the existing canal networkand by a lack of sufficient control structures.

3.2 Detailed Sub-prqect Desciption

3.2.1 Original Sub-project Concept

The original Sub-project concept consisted of the following items.

Protection from Saruft Intuion and Dry Season Freshwater Supply - In order to preventsalt water from entering the SMT Sub-project area, MARD proposed the construction of11 sluices. The sluices would operate (semi-) automatically depending on differences inwater levels at either side of the gates. Generally, lower water outside wil cause thegates to open, while lower water inside will cause the gates to close. During the dryseason, the sluices are kept closed to keep saline water out of the area and to preventfresh water from flowing to the sea. Flushing of canals by means of opening the sluicesat low tide would be done in the dry season to improve surface water quality whenneeded.

Improved Drainage - Expansion of the existing canal system through new canals andenlargement of existing canals (in total about 305 km of primary and 1360 km secondarycanals) would improve drainage and reduce inundation. Drainage is enhanced by thesluices because in the rainy season the gates are kept closed during rising tides.

Improved Freshwater Distribution - A number of water control sub-systems, consisting ofsecondary and tertiary sluices, secondary and tertiary canals, and improvements to maincanals, where needed.

Improved Transportaion Infrasuct - About 71 bridges related to canal reshapingwould serve as mitigation for interruption in waterway transport caused by the sluices.Boat lifts will be provided to mitigate impediments to small boat transport.

3.2.2 Current Status of Sub-project Implementation

The details of the status of the implementation of the Sub-project are contained in theMain Report and Annex Vill, and are summarised in the following sections.

MDWROP, Feasibility Study UpdateAnnex I, Environmental Impact Assessnent and Environmental Action Plan, August 1998 17

The Socialist Republic of VietnamlMARD/CPOMekong Delta Water Resources Development Project

3.22?1 Watr Conol Systern

The following components of the Sub-project have been completed, or are underconstruction in 1998:

(i) nine sluices are under construction or have been constructed: Tra Cu, Nha Tho,Trem, Vam Buon (completed before 1998), Cha Va, Thau Rau, Bac Trang, Ba Tramand Diep Thanh (under construction in 1998) (see map, Appendix A). Seven ofthese were components of the original FS. Where required, the canals associatedwith these sluices have also been developed;

lii) three main canals have been enlarged (Tra Cu, Nha Tho, and Vam Buon), and anumber of canals have been or are being constructed (Bang Da, Thong Nhat, LuongHoa, 3 February, Cau Hanh, Tra Ot, Chinh Plu, Tong Ton, Chanh Sam, Long, Hiep,and Ba So). Not all canals were excavated up to design dimensions.

3.22 Ch9es in Land LI. bum FS to nt Cndions

The ongoing implementation of the SMT Sub-project has already brought about land usechanges consisting mainly of (Figure 4):

(i) an increase in triple rice cropping of about 13,000 ha, largely in Region A;'ii) concomitant decreases in single and double rice cropping, again largely in Region A;

and(iii) a decrease in the overall area of land classified as 'Other', signifying a conversion

of land previously not used for agriculture into some type of culftivation.

Most of these changes have occurred in the upstream part of the Sub-project. Land usePatterns in the downstream part have changed little since the completion of the SMT-FS.This is largely because most of the improvements in water supply and drainage since thecompletion of the SMT-FS have not yet allowed intensifying cropping in the downstreamareas.

3.2.3 Remaining Elements of Sub-project Implementation

The elements of the Sub-project still to be implemented in addition to ongoing work in1998 (5 primary sluices, 82 km primary canal enlargement, 4 secondary sluices and 32km embankment) are:

(i) 8 main sluices;(ii) 92 secondary sluices;(iii) 12 main canals to be enlarged or deepened to increase drainage capacity;(iv) 14 secondary canal systems to be enlarged or deepened(v) continued improvement of the rural transportation system. Especially related to

bridges on the canal system;(vi) continued implementartion of the on farm water management system; and(vii) a programme of rural water supply and sanitation.

3.2.4 Land Use Scenario for Environmental Review

The future land use that can be practised in the SMT area, after project implementationwas determined during the preparation of the project. The land use planning is reported in



Annex V of the FS Main Report. Comparing the future situation with what could happenwithout system completion, major changes would be (Table 6):

0) an increase in the area culivating three crops per year, with most of this increaseoccurring in the form of triple rice and double nce/upland crops;

(ii) an increase in the area for sugarcane.

TawLad saiE,M J"V*&bpvw

land use (ha) PFrsent Without With W-WO1997 Project Project

Gross area 225,682 225,682 225,682 0

1. Agncultuuil area 171,837 171,837 171,441 -396(a) Annual crops 148,732 146,812 144,442 -2,370

-Tnile crowing 33282 46.954 98.206 5 2tbiple nce 33,282 31,954 61,206 29,252double rice + upland 0 15,000 37,000 22,000

-Dbuble cropoina 47g306 47.039 26.436 20,603double rice 47,306 47,039 26,436 -20,603Rice + upland 0 0 0 0

-Sinale crow 68.144 52.819 19.800 -019PtRice 61,53B 46,211 7,000 -39,211sugar cane 6,608 6,608 12,800 6,192

(b) Fruit/homestead 23,105 25,024 26,999 1,975

2. Forest 1,211 1,211 1,211 03. fishery 2352 2352 2352 04. Spewal se land 50,282 50,282 50,677 396

Cropping Intensities %) 166% 182% 230%Crop Diversification ( 3% 8% 14%

MDWRDP, Feasibility Study UpdateAnnex I, Environmental Impact Assessment and Environmentall Action Plan, August 1998 19

The Socialist Republic of Vietnam/MARDtCPOMekong Delta Water Resources Development Project

4. IMPACT ASSESSMENT FOR SOUTH MANG THIT SUB-PROJECT

Figure 6 contains a summary of the expected environmental impacts of the SMT project.The detailed rationale for the assessment of specific impacts is given below.

4.1 Detaled Descripton of Expected Environmental Impacts

4.1.1 Impacts on Physical Resources

4.1.1.1 Sub-prqject Impact on Sods

Sub-project Activites: Impact AssessmentConrcion and Operaion of Canals Postve and SignificantChanges h Lad Use Posiive and Significant

ConstmctFon and Operaton of Canals, and Changes in Land Use - Salts are expected toleach out frDm the soils rapidly. The consequent increases in soil grade areestimated to reach 10-20% within a period of 2 to 3 years.

Fresh water flushing causes leaching of the oxidised sulphates from soils, whichincreases- productivity of acidic soils. The actual increase of the productivitydepends on the amount of disturbance of the soil (e.g. ditching and landpreparation, etc.) and the depth of the pyritic layers. It is estimated that theproductivity on these soils increases with 10-30% within a 3 to 5 year period

4.1.1.2 Subpmect impacts on the Surfce Water RegIke

Sub-plojectActivites: Impact Assessment:Consuucin and Opeation of Cnals Posive and SigcantOperation of SiLiwc Positiv and Sgnificant

Construckon and OperatFion of Canals and Opeation of Shices - The overall hydraulicconditions in the Sub-project will improve, with improved freshwater supply in the dryseason. The completion of the water control system will have considerable positiveeffects on water levels in the area during both seasons. The change in the hydraulicregime in the area is essentially the objective of the project. The sluices prevent salinewater intrusion in the dry season. The improved canal system will allow fresh water to beconveyed mainly from the intake canals located along the Bassac River in Tra On Districtand from the Mang Thit River. This allows for irrigation of the entire area. In the rainyseason, the sluices will operate for drainage.

The effects on water levels relate to the change in regime, but not so much on maximumwater levels or flow velocities. In the dry season, the central and southern part of SMTwould in future be supplied with freshwater instead of experiencing saline water intrusion.The change in water levels will be limited to some 0.10 m at certain locations. Acontinually fluctuating water level (by tidal influence) in the past is changing towards asituation in which water levels in the central and southem areas will be more constant.These changes are assessed as positve and significant.

In the rainy season, the improved canal system together with the operation of the sluiceswill bring a considerable improvement to drainage conditions. Increased conveyancecapacity of canals together with preventing high tides to enter again, by autornatic

MDWRDP, Feasibility Study Update

Annex I, Environmental Impact Asesment and Environmental Action Plan, August 1998* 20


operation of the sluice gates, will prevent inundation and reduce water logging in thefields.

MDWRDP, Feasibility Study UpdateAnnex 1, Environmntdal Inct Asssment and Environmental Action Plan, August 1998 21


Sub-projeot Activit_ Environmental Resources _Physical _ - _ Ecdogical Socio-econorric

n~~~~~~~~~ ~ ~~~ 11 Cj x z Construction ac Operf on of Canals P P P I _ I I m I p M P _ MOperation of Sluices _ P P I _ M I S I _ I P M I PChangos h iJn Use and Commoqft Productdon P I I I_ P I _ I _ M I P _ PPopulation Growth MI I I I I I I _ I I M i P M PAppcatlon of Fers_l _ _ _ _ I I M I PAppicaton of Pestcides M I _ I-I I I _ I M M I pActivities Outside the Sub-oiect MPrRvision of ural Water Supply and Sanitation P P PConstructlon of Rura Acce Roads and Budges __ __ __ P P

Rgw, a Sta,mmay of wum4wm,ntdh k.cb. South aW~ S17* 6-n*o

b -l -ND IMpaW; l-qgricaM SSl*fcu. Ablty to Mit Lh*own or Not Pombe; M - gnfin and Migabs; UUIrdown; P-Posive Ond Sigift


The Socialist Republic of VietnamlMARD/CPOMekong Delta Water Resources Development Project

4.1.1.3 Sub-prject Impacts on Salnity

Sub-project Activites: Impact Assessment:Constction and Operation of Sluces PosWive and Sigrificant for AgictuiWal

ProductionUPstream Actvties InsknNicatl

Construction and Operation of Skkies - The salinity regime of the Sub-project is expectedto change substantially. The current situation during the dry season is that already a largearea is prevented from saline water intrusion. Wrth the completion of the water controlsystem, the surface water salinity of the entire Sub-project area is expected to be lessthan 4 ppt being the limit for use as irrigation water for paddy.

Upstream Activites - The continuing development of the Mekong Delta for increasedagricultural production in the recent past has lead to the situation that at present about15 to 15.5 million ton of paddy is produced annually. A 50% increase as compared toproduction levels in 1991/1992 (MDMP, 1994). The increase was partly obtained fromthe project area but mainly from delta wide development. The impact of the higher waterabstractions on salinity intrusion on the main branches of the Mekong River system andthus on the project area can be assessed as follows..

Comparing the present production figures with those projected in the MDMP, we see thattriple rice cropping is progressing more rapidly than anticipated in the defined ModerateLand and Water Use Scenario of the MDMP. Under these scenarios, some 15.2 milliontonnes of paddy per year would be attainable without a further increase in salinityintrusion as compared to 1991. In the Intermediate Scenario, about 15.6 million tonnes ofpaddy per year could be produced. This would result in a limited increase (3-6 km) offurther salinity intrusion in the Mekong River branches, but a substantial increase of some25 km would result in the Vam Co Rivers. The Extreme Land and Water Use Scenario,without restrictions on water abstractions, flood control and triple rice cutvation wouldresult in a paddy production in the Mekong Delta of 21 .5-million tonnes per year.

The conclusion could be that, as far as paddy production is concemed, since 1991/1992delta development has progressed along the line of the Extreme Scenario. By looking atthe production figures of 1997/1998, the- Delta is about halfway that scenario.

The current water abstractions do not necessarily follow the same trend as predicted inthe Extreme Development Scenario because an impressive change is taking placetowards the use of rice varieties of short duration. The 90-95 days varieties are nowwidely used, while the short duration varieties applied in the early nineties were of the105 -110 days types. The change is taking place in triple and double crop systems; thisgives more flexibility in the cropping pattems and results in less irrigation water use.Under the present TA for the preparation of the MDWRDP, both impacts cannot bequantified for the whole Mekong Delta. It would require an update of the MDMP.

Mathematical modelling of water flow and salinity propagation continued to improve sincecompletion of the MDMP Project. The results now obtained are believed to be moreaccurate and in line with observations of saline water intrusion in the southern part of theDelta.

In the MDMP simulations the 4g/1 salinity isolate was predicted to reach some 10 kmupstream of the Mang Thit River branch on the Co Chien River. This would happen with aprobability of occurrence of 10% (1 in 10 years low flow hydrograph as upstream


The Socialist Republic of VietnamnMARD/CPOMekong Delta Water Resources Development Project

boundary condition, and maximum water abstraction of the Extreme Scenario). Underaverage conditions, the situation would be closer to that predicted in the IntermediateScenario.

The modelling undertaken under this TA for the preparation of the MDWRDP, shows thatin case the limits of the Extreme Scenario for agricuttural production would be reached infuture, the 4 gil salinity isoline could reach the Mang Thit River. This could happen in 5 to10 years. In resuming the model simulations, no changes were made in the pattems ofwater abstractions, which were taken from the 1993-1994 studies to provide boundaryconditions for the simulations with the sub-models needed for the Sub-project. Theintroduction of the 90 days rice varieties has a significant positive impact on water useand hence on salinity intrusion. Salinity of 4g9/ is most likely not to reach the Mang ThitRiver under Extreme Scenario Water Use and 10% probability.

Positive impacts in reduction of saline water intrusion in the main branches of the riversystem are to be expected from flow regulation on the upper Mekong in China as well asfrom dams on Mekong tributaries in Laos. The Mekong River Commission (MRC) providesthe platform for the Mekong basin countries to discuss sharing of any additional water inthe dry season. Eventually, the Mekong Delta in Viet Nam could benefit also from suchdevelopments.

4.1.1X - Subproject kpacts on Swfece Water QuaOty

Pioject Activites: Impact AssessmentConstucto and Operato of Canas ad Sices PostveChages in Lwd UseeRural Wae Supy and Sanitaion PostiveAppicaton of Ferthes InsignificantAppicaton of Pestickd Unknown, MitigableUtuem Activitws .Itigable0pemon ofSluices Insigrnifcn

Construction and Operaion of Canals and Sluices, and Changes in Land Use - Asubstantial proportion of the Sub-project is underlain with acid soils with a relatively smallproportion of shallow acid soils. These areas are already releasing acidic water at theonset of the rainy season. However, this concerns a relatively low quantity of acid watercompared to the flushing capacity of the canal system. With the completion of the canalimprovements and the sluices, the flushing conditions will improve further. Hence,implementation of the SMT Sub-project would have positive impacts on acidic waterconditions.

The impact of increasing the flushing capacity and enhancing drainage on the reduction ofacidic surface water conditions is already observed in the Quan Lo Phung Hiep area. InCLPH, acid sulphate soils are far more widespread and more severe. In that area,extensive developments took place over the last ten years and a trend can now beobserved that the surface water quality is gradually improving. This is reported inAppendix C.

In SMT, with much less acid sulphate soils and better drainage conditions aftercompletion of the Sub-project as compared to QLPH, it can safely be assumed tha evenif canal excavation results in the temporary release of acids into surface water, this maynot be noticed because of the flushing capacity of the water control system.

MDWRDP. Feasibilry Study UpdateAnnex I, Environmental Impact Assessment and Environmental Action Plan, August 1998 24


Rural Water Supply and Sanitation - Without improvements in sanitation and propertreatment and disposal of household wastes, the increasing population will continue todegrade the surface water quality of the Sub-project. Pollutant levels within the Sub-project already appear to exceed most national and intemational water quality standards.The implementation of the proposed Rural Water Supply and Sanitation component as apart of the Sub-project would improve these conditions to some extent. This is assessedas positive.

Application of Fertilisers - From the future land use plan it is estimated that 73,700tonnes of fertiGiser will be required annually instead of the estimated 35,400 tonnes atpresent (Table 7). Compared to the future situation without implementation of the Sub-project, an increase of 32% could be expected with Sub-project implementation.

The limited data available suggests that the surface water quality in the area is already, oris close to, eutrophic. It is expected that incremental fertiliser inputs will not substantiallychange the water quality status of the Sub-Project. Total surface water volume in thearea will increase as a result of the expansion of the canal network and the reshaping of alarge numbers of existing canals. Hence, concentrations of nutrients would not increaseby the same rate as the fertiliser application rate increase. In addition, the completion ofthe water control structures will enable flushing of the canal system at low tide. Thisimpact is therefore assessed as Insignificant.

Application of Pesticides - It is estimated that approximately an additionalUSD 1,436,000 per year would be spent on pesticides and herbicides compared to acurrent application valued at USD 2,150,000 per year (Table 7). Compared to thesituation without implementation of the Sub-project, about a 30% increase could beexpected with the Sub-project. This impact is assessed as Unknown because existingbaseline information on pesticide concentrations in the Sub-project environment is non-existent. The most common compounds are Azodrin, Methyl Parathion, and- Basudin1OH, with various forms of other herbicides and rodenticides being used.

Both mitigation and monitoring are recommended.

With respect to mitigation, This is best accomplished with an IPM program. TheMARD/IDA Agricultural Rehabilitation Project comprises a Plant Protection Sub-Component, which is being implemented in 35 provinces through the provincial PlantProtection Sub-departments. All provinces in the Mekong Delta participate in theprogramme. In each of the provinces of interest to the MDWRDP, so far roughly 10,000farmers were trained on plant protection in 52 Farmer Field Schools. In addition, 20demonstration sites for tolerant rice varieties to Brown Plant Hopper and Blast diseasewere established. Results obtained are very encouraginge: On average the number ofpesticide applications in IPM fields reduced by about 90%, participants spent about 30 to40% less on pesticides, while production increased by 0.7 tonnelhatyear. Apart from theenvironmental benefit, application of IPM increases the farmers' profit by about USD 15per ha per year. It is recommended that the spreading of IPM techniques be continued,possibly this can best be realised through national programnes and not be set upspecifically for the Sub

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