BASELINE ASSESSMENT REPORT | MRC SEA for HYDROPOWER ON THE MEKONG MAINSTREAM I MRC SEA FOR HYDROPOWER ON THE MEKONG MAINSTREAM SUMMARY BASELINE ASSESSMENT REPORT 15 April 2010 The MRC SEA of Hydropower on the Mekong mainstream comprises 4 main phases: (i) scoping, (ii) baseline assessment, (iii) opportunities & risks assessment, and (iv) avoidance, enhancement and mitigation assessment. This report formally concludes the baseline assessment phase of the SEA and documents the outcomes of the baseline consultations and SEA team analysis. The Baseline Assessment Report has two volumes: VOLUME I: Summary Baseline Assessment Report VOLUME II: Baseline Assessment Working Papers 1 ICEM – International Centre for Environmental Management BASELINE ASSESSMENT REPORT | MRC SEA for HYDROPOWER ON THE MEKONG MAINSTREAM Disclaimer This document was prepared for the Mekong River Commission Secretariat (MRCS) by a consultant team engaged to facilitate preparation of a Strategic Environment Assessment (SEA) of proposals for mainstream dams in the Lower Mekong Basin. While the SEA is undertaken in a collaborative process involving the MRC Secretariat, National Mekong Committees of the four countries as well as civil society, private sector and other stakeholders, this document was prepared by the SEA Consultant team to assist the Secretariat as part of the information gathering activity. The views, conclusions, and recommendations contained in the document are not to be taken to represent the views of the MRC. Any and all of the MRC views, conclusions, and recommendations will be set forth solely in the MRC reports. This document incorporates a record of stakeholder consultations and subsequent analysis. Whether they attended meetings or not all stakeholders have been invited to submit written contributions to the SEA exercise via the MRC website. For further information on the MRC initiative on Sustainable Hydropower (ISH) and the implementation of the SEA of proposed mainstream developments can be found on the MRC website: http://www.mrcmekong.org/ish/ish.htm and http://www.mrcmekong.org/ish/SEA.htm The following position on mainstream dams is provided on the MRC website in 2009. MRC position on the proposed mainstream hydropower dams in the Lower Mekong Basin More than eleven hydropower dams are currently being studied by private sector developers for the mainstream of the Mekong. The 1995 Mekong Agreement requires that such projects are discussed extensively among all four countries prior to any decision being taken. That discussion, facilitated by MRC, will consider the full range of social, environmental and cross‐sector development impacts within the Lower Mekong Basin. So far, none of the prospective developers have reached the stage of notification and prior consultation required under the Mekong Agreement. MRC has already carried out extensive studies on the consequences for fisheries and peoples livelihoods and this information is widely available, see for example report of an expert group meeting on dams and fisheries. MRC is undertaking a Strategic Environmental Assessment (SEA) of the proposed mainstream dams to provide a broader understanding of the opportunities and risks of such development. Dialogue on these planned projects with governments, civil society and the private sector is being facilitated by MRC and all comments received will be considered. 2 ICEM – International Centre for Environmental Management BASELINE ASSESSMENT REPORT | MRC SEA for HYDROPOWER ON THE MEKONG MAINSTREAM CONTENTS 1 Introduction .......................................................................................9 2 Economic systems............................................................................12 2.1 Past trends and current situation..............................................................12 2.1.1 Issue: National and regional economic implications of large scale natural resource based development in the LMB. ....................................................................................................................................12 2.2 Past trends and current situation..............................................................15 2.2.1 Issue: What are the economic costs and benefits of sectoral development in the LMB countries ......15 2.3 Past trends and current situation..............................................................15 2.3.1 Issue: What is the distribution of economic benefits between different areas, groups and sectors?..15 2.3.2 Summary of current status ....................................................................................................................23 2.4 Future trends without the LMB mainstream hydropower development..23 2.4.1 Issue: National and regional economic implications of large scale natural resource based development in the LMB. ....................................................................................................................................23 2.5 Future trends without the LMB mainstream hydropower development..25 2.5.1 Issue: What are the economic costs and benefits of sectoral development in the LMB countries ......25 2.6 Future trends without the LMB mainstream hydropower development..26 2.6.1 Issue: What is the distribution of economic benefits between different areas, groups and sectors? .26 References ..........................................................................................................28 3 Energy and power ............................................................................30 3.1 Past trends and current situation..............................................................30 3.1.1 Issue 1: Electricity demand growth........................................................................................................30 3.1.2 Issue 2: Buyer and seller motivations for cross‐border power trade ....................................................33 3 ICEM – International Centre for Environmental Management BASELINE ASSESSMENT REPORT | MRC SEA for HYDROPOWER ON THE MEKONG MAINSTREAM 3.1.3 Issue 3: GmS and LMB Energy resource Base ........................................................................................36 3.1.4 Issue 4: Alternative demand‐side and supply‐side options ...................................................................38 3.1.5 Issue: Trends in other issues related to regional power benefits..........................................................42 3.2 Future trends without LMB development.................................................44 3.3 References.................................................................................................45 4 hydrology and sediment ..................................................................46 4.1.1 Phasing of the SEA Hydrology and sediment assessment .....................................................................46 4.2 Hydrology ..................................................................................................46 4.2.1 Thematic context...................................................................................................................................46 4.2.2 hydrological issues.................................................................................................................................48 4.2.3 Information sources & uncertainties.....................................................................................................48 4.2.4 Drivers of change in the Mekong hydrology & Sediment......................................................................49 4.2.5 Flow Variation – Past trends & current situation ..................................................................................50 4.2.6 Timing and duration of the hydro‐biogical seasons – Past trends & current situation .........................51 4.2.7 Flow provenance – Past trends & current situation ..............................................................................51 4.2.8 Tonle Sap flow reversal– Past trends & current situation .....................................................................53 4.2.9 Flooding in the Tonle Sap – Past trends & current situation .................................................................55 4.3 Sediment ...................................................................................................55 4.3.1 Thematic context...................................................................................................................................55 4.3.2 Sediment issues .....................................................................................................................................56 4.3.3 Information sources & uncertainties.....................................................................................................57 4.3.4 Drivers of change in the Mekong SEDIMENT.........................................................................................57 4.3.5 The MEkong Sediment Load – past and current trends ........................................................................57 4.3.6 Sediment transport capacity..................................................................................................................58 4.3.7 Bedload dynamics..................................................................................................................................60 4.3.8 Deep pools.............................................................................................................................................63