SANAKHAM HYDROPOWER PROJECT Transboundary Environmental and Social Impact Assessment & Cumulative Impact Assessment Transboundary Environmental and Social Impact Assessment & Cumulative Impact Assessment TABLE OF CONTENTS 1 INTRODUCTION ..................................................................................................................................... 13 1.1 BACKGROUND ...................................................................................................................................... 13 1.2 THE MEKONG RIVER AND THE MEKONG RIVER BASIN ........................................................................ 15 1.3 MAIN OBJECTIVE ................................................................................................................................. 18 1.4 FRAMEWORK AND SCOPE OF INVESTIGATION ...................................................................................... 18 1.4.2 General Framework ........................................................................................................................ 18 1.4.3 Scope of Investigation ..................................................................................................................... 19 1.4.4 Study Zone ...................................................................................................................................... 20 1.5 METHODOLOGY ................................................................................................................................... 21 1.5.2 Relevant Regulatory Framework in Lao PDR ................................................................................ 21 1.5.3 Methology for Impact Assessment................................................................................................... 22 1.6 LIMITATIONS AND PROBLEM SOLVING IN DATA COLLECTION ............................................................. 23 1.7 POLICY AND LEGAL FRAMEWORK ....................................................................................................... 24 1.7.1 Sustainable Hydropower Development ........................................................................................... 24 1.7.2 International Good Practice ........................................................................................................... 27 1.7.3 The Mekong River Commission (MRC) Agreement ........................................................................ 29 1.7.4 Relevant Environmental and Social Legislation in Lao PDR ......................................................... 29 1.8 DAMS IN THE LOWER MEKONG BASIN ................................................................................................. 37 1.8.1 Mainstream Dams ........................................................................................................................... 37 1.8.2 Lower Mekong Dams ...................................................................................................................... 41 2 SANAKHAM ENVIRONMENTAL PROJECT DESCRIPTION ........................................................ 46 3 BASELINE OF ENVIRONMENTAL AND SOCIAL CONDITIONS ................................................. 48 2.1 MEKONG RIVER FLOWS ....................................................................................................................... 48 2.1.1 General Background ....................................................................................................................... 48 2.1.2 Flows in the Main Stream ............................................................................................................... 52 2.2 SEDIMENTATION .................................................................................................................................. 76 3.2.1 Mekong River Basin ........................................................................................................................ 76 3.2.2 Sidementat Runoff Transport in the Mekong River............................................................................ 78 3.3 FISH MIGRATION AND FISHERIES ......................................................................................................... 80 3.3.1 Fish Migration ................................................................................................................................ 80 3.4 NAVIGATION ...................................................................................................................................... 109 3.4.1 Waterway Transport ..................................................................................................................... 109 3.4.2 Transhipping Route and Period .................................................................................................... 111 3.4.3 Problems Encountered and Future Development ......................................................................... 113 3.4.4 Agreements for Transhipping between Countries .................................................................... 114 3.4.5 Transhipping in the study Area ..................................................................................................... 114 1 Transboundary Environmental and Social Impact Assessment & Cumulative Impact Assessment 3.4.6 Navigation in the Study Area ........................................................................................................ 115 3.5 WATER QUALITY ............................................................................................................................... 120 3.5.1 Water quality in the Mekong River ............................................................................................... 120 3.5.2 Water Quality in the SanakhamHPP Area .................................................................................... 124 3.6 DAM SAFETY ..................................................................................................................................... 126 3.7 CLIMATE CHANGE ............................................................................................................................. 127 3.8 SOCIAL BASELINE CONDITION ........................................................................................................... 128 3.8.1 Social Overview of the Study Area and LMB Countries ............................................................... 128 3.8.2 Social Condition in Zone 1 (Thai-Laos) ....................................................................................... 131 3.8.3 Social Condition in Zone 2 (Southern Laos) ................................................................................. 147 3.8.4 Social Condition in Zone 3(Cambodia and Tonle Sap Lake) ........................................................ 158 3.9.3 Social Condition in Zone 4 (Sounthern Vietnam and Mekong Delta) ............................................. 169 4 HYDROLOGY AND SEDIMENT CHANGED FROM THE PROJECT DEVELOPMENT .......... 179 4.1 DEVELOPMENT OF SCENARIOS AND MODELING APPROACH .............................................................. 179 4.1.1 Background ................................................................................................................................... 179 4.1.2 The Mekong Sanakham HPP Development Scenarios (2017 and 2030) ...................................... 179 4.1.3 The Hydrologic Models ................................................................................................................ 181 4.3 HYDROLOGICAL AND SEDIMENTATION CHANGES .............................................................................. 187 4.3.1 Detail Analysis of Flow ................................................................................................................. 187 4.3.2 Details Analysis of Sedimentation ................................................................................................ 198 5 TRANS-BOUNDARY AND CUMULATIVE IMPACT ASSESSMENT ........................................... 207 5.1 FISH MIGRATION AND FISHERIES ....................................................................................................... 207 5.1.1 Transboundary impact .................................................................................................................. 207 5.1.2 Cumulative Impact ........................................................................................................................ 209 5.2 NAVIGATION ...................................................................................................................................... 210 5.2.2 Transboundary impact .................................................................................................................. 210 5.2.3 Cumulative Impact ........................................................................................................................ 211 5.3 WATER QUALITY ............................................................................................................................... 211 5.3.1 Transboundary impact .................................................................................................................. 211 5.3.2 Cummulative Impact ..................................................................................................................... 213 5.4 DAM SAFETY ..................................................................................................................................... 214 5.5 CLIMATE CHANGE