50898 v3 CLIMATE CHANGE IMPACT AND ADAPTATION STUDY FOR BANGKOK METROPOLITAN REGION Final Report Appendix PANYA CONSULTANTS CO., LTD. March 2009 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Contents CONTENTS CONTENTS I ABBREVIATIONS IX APPENDIX A SOCIO-ECONOMICS A1 General A-1 A2 Socio-economic Development A-1 A2.1 Population A-1 A2.2 Poverty A-5 A2.3 Economy A-6 A3 2008 Situation A-11 A3.1 Administration A-11 A3.2 Population A-11 A3.3 Economy A-11 A4 Master Plan and Future (2050) A-12 A4.1 Population A-12 A4.2 Economy A-13 B BUILDINGS AND HOUSING B1 Urbanization B-1 B1.1 Topography B-1 B1.2 Historical Growth B-2 B1.3 Modern-day Growth B-3 B1.4 Urban and Regional Planning B-7 B2 Buildings and Housing B-10 B2.1 Past Development B-10 B2.2 Present Situation B-11 B2.3 Condensed Housing Situation B-11 C TRANSPORTATION C1 Historical Background C-1 C2 Present Transportation in the BMR C-2 C2.1 Road Infrastructure C-2 C2.2 Rail Infrastructure C-2 C2.3 Waterway Infrastructure C-2 C3 Transportation Master Plan C-5 C3.1 Expressway Plan C-5 C3.2 Road Improvement Plan C-8 C3.3 Urban Public Transport Plan C-8 C3.4 Railway and Mass Rapid Transit C-14 D WATER SUPPLY AND SANITATION D1 Water Supply D-1 D1.1 Present Situation D-1 D1.2 Water Demand Projection D-2 D1.3 MWA Development Project D-6 D2 Wastewater Treatment System D-6 D2.1 Present Situation D-6 D2.2 Projected Wastewater Generation D-11 D3 Solid Waste Management D-12 I Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Contents D3.1 Present Situation D-12 D3.2 Projected Solid Waste Generation D-14 E PUBLIC HEALTH E1 General E-1 E2 Projection E-2 F ENERGY F1 Organization of Energy Administration F-1 F2 Historical Development F-2 F3 Present Situation F-3 F3.1 Energy Consumption in Bangkok and Samut Prakarn F-3 F3.2 Consumption Activities F-5 F4 Development Plans F-6 F4.1 Strengthening Transmission of the EGAT F-6 F4.2 Development Projects of the MEA F-6 F5 Future Projection F-7 F5.1 Energy Consumption F-7 F5.2 Future Energy Infrastructures F-9 G FLOOD MANAGEMENT G1 Historical Knowledge Base G-1 G1.1 Causes of Flooding G-1 G1.2 Major Flood Occurrences in Bangkok G-1 G2 Present Situation G-3 G2.1 Flood Control from the Northern of Thailand G-5 G2.2 Flood Control in Bangkok G-5 G3 Master Plan for Flood Protection and Mitigation G-7 G4 Future Plan for 2050 G-8 H SEA LEVEL RISE AND STORM SURGE H1 Sea Level Rise H-1 H2 Storm Surge H-6 I LAND SUBSIDENCE I1 Problems I-1 I1.1 Legal Prevention and Mitigation Measures I-1 I1.2 Economic Prevention and Mitigation Measures I-4 I1.3 Technical Prevention and Mitigation Measures I-4 I2 Present Situation I-5 I3 Forecast of Future Land Subsidence I-8 J METEOROLOGY AND HYDROLOGY J1 General Condition J-1 J1.1 Climate J-1 J1.2 River Morphology J-3 J2 Basic Analysis J-3 J2.1 Precipitation J-3 J2.2 Temperature and Evapotranspiration J-8 J2.3 Runoff J-9 J2.4 Water Level and Sea Level J-10 II Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Contents K MATHEMATIC MODEL DEVELOPMENT AND SIMULATION K1 Model Development K-1 K1.1 Model Setup K-1 K1.2 Model Inputs K-2 K1.3 Rainfall-Runoff Model K-10 K1.4 Hydrodynamic Model K-20 K1.4.1 Upper Chao Phraya Model K-20 K1.4.2 Lower Chao Phraya Model K-21 K2 Simulation K-25 K2.1 Return Period K-25 K2.2 Scenarios K-25 K2.3 Flood from the Upper Chao Phraya River Basin K-26 K2.4 Flood in the Lower Chao Phraya River Basin K-28 L IMPACT ASSESSMENT L1 Methodology L-1 L1.1 Population L-2 L1.2 Buildings and Housing L-3 L1.3 Transportation L-7 L1.4 Water Supply and Sanitary System L-7 L1.5 Energy L-8 L1.6 Public Health L-9 L2 Impact Assessment Results L-9 L2.1 Affected Population L-10 L2.2 Affected Buildings L-12 L2.3 Losses of Income L-12 L2.4 Affected Infrastructures L-15 L2.5 Affected Public Health Care System L-15 M ADAPTATION AND PROPOSAL M1 General M-1 M2 Review of Adaptative Practices M-1 M3 Adaptation Options and Proposal M-3 M3.1 Structural Measures M-4 M3.2 Preliminary Cost Estimate M-6 M3.3 Preliminary Economic Evaluation M-17 M3.4 Non-structural Measures M-18 N CONSULTATION WITH STAKEHOLDERS N1 Technical Consultation 1 N-1 N2 Technical Consultation 2 N-2 N3 Final Stage Consultation N-3 REFERENCES R-1 LIST OF TABLES Table A2.1-1 Population in the BMR (2003-2007) A-2 Table A2.1-2 Households in the BMR (2003-2007) A-2 Table A2.1-3 Population of Bangkok and Samut Prakarn by District A-2 Table A2.1-4 Bangkok Communities (2006) A-4 Table A2.2-1 Poverty Line and the Poor in the BMR A-5 Table A2.3-1 GDP at 2006 Current Market Prices of the BMR A-6 III Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Contents Table A2.3-2 GDP of Bangkok A-7 Table A2.3-3 GDP of Samut Prakarn A-8 Table A2.3-4 Economic Zones in the BMR A-9 Table A3.1-1 Administration of the BMR A-11 Table A3.2-1 Population of the BMR (2008) A-11 Table A3.3-1 GDP of BMR (2008) A-11 Table A4.1-1 Population Projection including Non-registered (2050) A-12 Table A4.1-2 Household Projection for the BMR (2050) A-12 Table A4.2-1 GDP Projection for the BMR (2050) A-13 Table B1.3-1 Urbanization Growth of the BMR (2003) B-4 Table B1.3-2 Number of Building in Bangkok by District (2008) B-5 Table B2.1-1 Population and Housing Growth in the BMR B-10 Table C2.3-1 Average Daily Passengers Using the Chao Phraya Express Boats C-4 Table C2.3-2 Average Daily Ferry Boat Passengers Crossing C-4 the Chao Phraya River Table C2.3-3 Average Daily Boat Passengers at Piers along Khlong Saen Saep C-5 Table C3.1-1 Expressway and Rapid Transit Authority of Thailand Projects C-6 Table C3.2-1 Urgent Road Improvement Plans C-10 Table C3.2-2 Urgent Projects of the DOH C-11 Table C3.2-3 Urgent Projects of the DOR C-12 Table C3.2-4 Urgent Projects of the BMA C-13 Table C3.4-1 Details of Proposed Red Line Phase 1 C-15 Table D1.1-1 MWA Service Area and Performance (2007) D-1 Table D1.1-2 PWA Service Performance (2007) D-2 Table D1.1-3 Details of the MWA Water Treatment Plants D-2 Table D1.2-1 Water Supply in Bangkok and Samut Prakarn D-4 Table D2.1-1 Capacity of DDS Wastewater Treatment Plants D-7 Table D2.1-2 Capacity of Small Wastewater Treatment Plants D-7 Table D2.1-3 Water Quality Control Plants in Bangkok D-10 Table D2.1-4 Wastewater Management in Samut Prakarn D-11 Table D2.2-1 Projected Wastewater Generation D-11 Table D3.1-1 General Solid Waste management at Transfer Stations (2007) D-12 Table F3.1-1 Petroleum Products Consumption in the BMR F-4 Table F3.2-1 Energy consumption in Bangkok and Samut Prakarn (2006) F-5 Table F4.2-1 Underground Cable Projects F-7 Table F5.1-1 Energy Consumption Projection in Bangkok and F-8 Samut Prakarn (2021) Table F5.1-2 Energy Consumption Projection in Bangkok and F-9 Samut Prakarn (2050) Table G3-1 Flood Protection Budget in the RID Master Plan G-8 Table H1-1 Projected Global Average Sea Level Rise H-1 Table J2.1-1 The Selected Rainfall Stations in the Chao Phraya River Basin J-4 Table J2.1-2 Maximum Rainfall over the Chao Phraya River Basin for J-7 Consecutive Days Table J2.2-1 Increasing Factor of Evapotranspiration for A1FI and B1 J-8 Table J2.2-2 List of Evaporation Stations J-8 Table J2.3-1 List of Stream Gauging Stations J-9 Table J2.3-2 Maximum Discharge in the Chao Phraya and Pasak Rivers J-10 Table J2.4-1 List of Water Level Gauging Stations J-10 Table K1.2-1 Operation Rule and Area-Capacity Curve of K-4 the Major Reservoirs Table K1.2-2 Target Water Level Control in Major Drainage Canals K-5 Table K1.2-3 Improvement of Flood Protection System in the Eastern Area of K-7 Bangkok Table K1.3-1 Catchment Area of Sub-basins and Index Stations K-11 IV Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Contents Table K1.3-2 Weighting Factor of Rainfall and Evaporation Stations of Sub-basins K-12 Table K1.3-3 Calibrated Parameters of the Nam Model K-19 Table K1.4-1 Detailed Description of the River Branches in the Upper Model K-20 Table K1.4-2 Detailed Description of the River and Canal Branches in K-23 the Lower Model Table K2.2-1 Scenarios for Simulation Study K-26 Table K2.3-1 Volume and Peak Discharge of Flood at C.2 and K-26 C.13 Gauging Stations Table K2.4-1 The Inundation Area in Different Flood Depth from K-28 Simulation Results Table L1-1 Summary of Assessed Damage L-2 Table L1.1-1 Flood Impact on Population L-2 Table L1.2-1 Flood Damage Rate of Building and Asset L-3 Table L1.2-2 Unit Price of Building and Construction L-3 Table L1.2-3 Depreciation Rate of Building and Construction L-4 Table L1.2-4 Average Book Value of Residential Building and Asset L-5 Table L1.2-5 Average Book Value of Commercial Building and Asset L-5 Table L1.2-6 Average Book Value of Industrial Building and Asset L-6 Table L1.5-1 Unit Cost of Electrical Damage by Service-district L-8 Table L2-1 The Damage Cost Estimation L-9 Table L2-2 Incremental Damage Cost L-10 Table L2.1-1 Affected Population under C2008-T30 and L-11 C2050-LS-SR-SS-A1FI-T30 Scenarios Table L2.1-2 Affected Population in Various Scenarios L-12 Table L2.2-1 Affected Building of Case C2008-T30 and L-13 C2050-LS-SR-SS-A1FI-T30 Table L2.2-2 Affected Building and Housing in Different Cases L-14 Table L2.2-3 Damage Cost of Building and Housing in Different Cases L-14 Table L2.3-1 Losses of Income Related to Duration of Flood L-15 Table M3.1-1 Proposed Pumping Capacities in the Western Area of Bangkok M-5 Table M3.2-1 Designed Dike Crest Elevations in the Eastern Area of M-8 the Chao Phraya River Table M3.2-2 Designed Dike Crest Elevations in the Western Area of M-9 the Chao Phraya River Table M3.2-3 Unit Costs of Dike, Pump and Canal Improvement, and M-10 Coastal Erosion Protection Table M3.2-4 Cost Estimate of Flood Protection Improvement in M-12 the Eastern Area of the Chao Phraya River Table M3.2-5 Cost Estimate of Flood Protection Improvement in M-13 the Western Area of the Chao Phraya River Table M3.3-1 Investment Cost of Flood Protection Improvement Project M-11 Table M3.3-2 Annual Benefit of 30 Year Return Period M-15 Table M3.3-3 Annual Benefit of 100 Year Return Period M-15 Table M3.3-4 Cost Benefit Analysis (Base Case) M-16 Table M3.3-5 Cost Benefit Analysis (Real Growth) M-17 LIST OF FIGURES Figure A1-1 Bangkok Metropolitan Region (BMR) A-1 Figure A2.1-1 Condensed Housing Communities in Bangkok A-5 Figure A2.3-1 Economic Zones in the BMR A-10 Figure B1.1-1 General Topography of the BMR B-1 Figure B1.2-1 Urbanized Area of Bangkok B-2 Figure B1.3-1 Urban Built-up Area (2003) B-4 Figure B1.3-2 Districts of Bangkok and Samut Prakarn B-6 V Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Contents Figure B1.4-1 Land Use Plan of Bangkok and Samut Prakarn (2006) B-8 Figure B1.4-2 Regional Land Use Conceptual Plan (2057) B-9 Figure C2.1-1 Transportation Network in the BMR C-3 Figure C3.1-1 Expressway and Rapid Transit Authority of Thailand Projects C-7 Figure C3.2-1 Urgent Road Improvement Plans C-9 Figure D1.1-1 MWA Water Treatment Plants D-3 Figure D1.2-1 Water Demand Projection of Bangkok and Samut Prakarn D-4 Figure D1.3-1 MWA Development Project D-5 Figure D2.1-1 Quantity of Wastewater in Bangkok D-6 Figure D2.1-2 Proportion of Wastewater in Bangkok D-7 Figure D2.1-3 Service Area of Decentralized Wastewater Treatment Plants D-9 Figure D3.1-1 Solid Waste Management in Bangkok D-13 Figure E1-1 Diagram Pathways of Health Impacts E-1 Figure E2-1 Incidence Rate of Infectious Diseases in Bangkok (2003-2007) E-2 Figure E2-2 Trends of Infectious Diseases in Bangkok (2003-2050) E-4 Figure F1-1 Organization of Energy Agencies F-1 Figure F5.1-1 Pattern of Fuel Substitution Projection (2007-2021) F-8 Figure G1.2-1 Satellite Images (TERRA MODIS) on November 12 and G-3 December 21, 2006 Figure G2-1 Bangkok and Vicinity Flood Protection System G-4 Figure H1-1 Observed Sea Level Rise during the 20th Century H-1 Figure H1-2 Projected Sea Level Rise for 6 SRES H-1 Figure H1-3 Relative Vulnerability of Coastal Deltas (2050) H-2 Figure H1-4 Relative Sea Level Rise in Thailand by Sommart and Itti (2007) H-4 Figure H1-5 Relative Sea Level Rise in Thailand by Supharatid (2007) H-4 Figure H1-6 Aerial Photo of the Upper Gulf of Thailand H-5 Figure H1-7 Land Subsidence on the Chao Phraya River Delta H-6 Figure H2-1 Typhoon Linda from GMS-05 Satellite Image H-6 Figure H2-2 Buoy Location in the Gulf of Thailand H-7 Figure H2-3 Typhoon Linda Track H-7 Figure H2-4 Study Location H-8 Figure H2-5 Wind Fields on November 3, 1997, every 6 hours (NOGAPS) H-9 Figure H2-6 Wave Fields on November 3, 1997, every 6 hours (WAM output) H-9 Figure H2-7 Peak Wave in November 3, 1997 (WAM output) H-9 Figure H2-8 Time Series of Wave Parameters at HHN Station H-10 Figure H2-9 Tidal Stations in the Upper Gulf of Thailand H-10 Figure H2-10 Water Levels on Nov. 4, 1997 H-11 Figure I1.1-1 Critical Groundwater Zone Map (1983) I-2 Figure I1.1-2 Critical Groundwater Zone Map (1995) I-3 Figure I1.3-1 Land Subsidence Benchmarks and Monitoring Wells I-4 Figure I2-1 Land Subsidence in Bangkok and Adjacent Areas (2007) I-5 Figure I2-2 Correlation between Land Subsidence and Groundwater Level I-7 Figure I2-3 Relationship between Land Subsidence and Groundwater Level I-8 Figure I3-1 Land Subsidence Rate (1979–2007) I-8 Figure I3-2 Average Land Subsidence Rate I-9 Figure I3-3 Accumulate Land Subsidence (1978-2007) I-9 Figure I3-4 Accumulate Land Subsidence (2007-2050) I-9 Figure J1.1-1 Monsoons and Tropical Cyclones in Thailand J-1 Figure J1.1-2 Average Rainfall over the Chao Phraya River Basin J-2 Figure J1.1-3 Mean Monthly Temperature in the Chao Phraya River Basin J-2 Figure J1.1-4 Mean Monthly Pan Evaporation in the Chao Phraya River Basin J-2 Figure J2.1-1 Location of Hydro-meteorological Stations J-5 Figure J2.1-2 Annual Rainfall Isohyet of the Chao Phraya River Basin J-6 Figure J2.1-3 Rainfall Pattern in the Chao Phraya River Sub-basin in 1995 J-7 Figure J2.3-1 Discharge Hydrographs in the Chao Phraya and Pasak Rivers J-9 VI Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Contents Figure J2.4-1 Sea Level at the River Mouths of Chao Phraya and Tha Chin J-11 Figure J2.4-2 Water Level along the Chao Phraya River in 1995, 2002 and 2006 J-12 Figure K1.1-1 Schematic Diagram of Model Setup K-2 Figure K1.2-1 River/Canal Network of the Model Setup K-3 Figure K1.2-2 Schematic Diagram of the Model in 1995 K-8 Figure K1.2-3 Schematic Diagram of the Model in 2002 K-8 Figure K1.2-4 Schematic Diagram of the Model in 2050 K-9 Figure K1.3-1 The Chao Phraya River Sub-basins and the Thiessen Polygon of K-10 NAM Model Figure K1.3-2 Structure of the NAM Model K-11 Figure K1.3-3 Simulated and Estimated Discharges of K-13 the Upper Ping River Basin (1995-1999) Figure K1.3-4 Simulated and Estimated Discharges of K-13 the Wang River Basin (1995-1999) Figure K1.3-5 Simulated and Estimated Discharges of) K-14 the Yom River Basin (1995-1999 Figure K1.3-6 Simulated and Estimated Discharges of K-14 the Upper Nan River Basin (1995-1999) Figure K1.3-7 Simulated and Estimated Discharges of K-15 the Khwae Noi River Basin (1995-1999) Figure K1.3-8 Simulated and Estimated Discharges of K-15 the Upper Pasak River Basin (1995-1999) Figure K1.3-9 Simulated and Estimated Discharges of K-16 the Upper Ping River Basin (1999-2003) Figure K1.3-10 Simulated and Estimated Discharges of K-16 the Wang River Basin (1999-2003) Figure K1.3-11 Simulated and Estimated Discharges of K-17 the Yom River Basin (1999-2003) Figure K1.3-12 Simulated and Estimated Discharges of K-17 the Upper Nan River Basin (1999-2003) Figure K1.3-13 Simulated and Estimated Discharges of K-18 the Khwae Noi River Basin (1999-2003) Figure K1.3-14 Simulated and Estimated Discharges of K-18 the Upper Pasak River Basin (1999-2003) Figure K1.4-1 Simulated Results and Observed Data at C.2 Gauging Station K-21 Figure K1.4-2 Inundation Map in 1995 by CTI Engineering Co., Ltd. and K-22 by the Consultant Figure K1.4-3 Inundation Area on Nov 4, 2002 from Satellite Image and K-22 Simulation Result Figure K1.4-4 Stage Hydrographs of Simulated and Observed Data at K-24 Gauging Stations Figure K2.3-1 Flood Hydrographs at Nakhon Sawan (C.2) in Different Scenarios K-27 Figure K2.4-1 Maximum Water Depth of Case C2008-T30 and K-29 C2050-LS-SR-A1FI-T30 Figure K2.4-2 The Inundated Area in Different Durations K-31 (Case C2050-LS-SR-A1FI-T30) Figure K2.4-3 Maximum Water Level in the Chao Phraya River at K-32 Different Return Periods Figure K2.4-4 Water Level at Index Stations in the Chao Phraya River at K-33 10-Year Return Period Figure K2.4-5 Water Level at Index Stations in the Chao Phraya River at K-34 30-Year Return Period Figure K2.4-6 Water Level at Index Stations in the Chao Phraya River at K-35 100-Year Return Period VII Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Contents Figure M3.1-1 Maximum Inundation Are in Case of M-6 With and Without the Proposed Adaptation Figure M3.2-1 Dike Improvement M-7 Figure M3.3-1 Flood Damage Cost With and Without the Project for M-14 30-Year Return Period Figure M3.3-2 Flood Damage Cost With and Without the Project for M-14 100-Year Return Period Figure M3.4-1 Disaster Management Organization Chart of Thailand M-21 VIII Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Abbreviations ABBREVIATIONS Thailand Government / Agencies BECL : Bangkok Expressway Public Company Limited BMA : Bangkok Metropolitan Administration BMTA : Bangkok Mass Transit Authority BOI : Board of Investment of Thailand BRA : Bureau of Registration Administration BTS : Bangkok Mass Transit Public Company Limited CU : Chulalongkorn University DAE : Department of Agricultural Extension, MOAC DCP : Department of City Planning, BMA DDC : Department of Disease Control, MOPH DDPM : Department of Disaster Prevention and Mitigation, MOI DDS : Department of Drainage and Sewerage, BMA DEDE : Department of Alternative Energy Development and Efficiency, MOEN DEQP : Department of Environment and Quality Promotion, MONRE DGR : Department of Groundwater Resources, MONRE DIW : Department of Industrial Works, MOI DMCR : Department of Marine and Coastal Resources, MONRE DMF : Department of Mineral Fuels, MOEN DMS : Department of Medical Service, BMA DOAE : Department of Agriculture Extension, MOAC DOE : Department of Environment, BMA DOEB : Department of Energy Business, MOEN DOF : Department of Fisheries, MOAC DOH : Department of Highway, MOT DOPA : Department of Provincial Administration, MOI DOR : Department of Rural Roads, MOT DPT : Department of Public Works and Town & Country Planning, MOI DPW : Department of Public Works, BMA DWR : Department of Water Resources, MONRE EGAT : Electricity Generating Authority of Thailand EPPO : Energy Policy and Planning Office, MOEN ETA : Expressway and Rapid Transit Authority of Thailand GISTDA : Geo-Informatics and Space Technology Development Agency HD : Harbor Department HDD : Hydrographic Department, Royal Thai Navy HDP : Health Department, BMA I-EA-T : Industrial Estate Authority of Thailand LDD : Land Development Department, MOAC MD : Marine Department, MOT MEA : Metropolitan Electricity Authority MICT : Ministry of Information and Technology MOAC : Ministry of Agriculture and Cooperative MOC : Ministry of Commence MOEN : Ministry of Energy MOF : Ministry of Finance MOPH : Ministry of Public Health MOI : Ministry of Interior MONRE : Ministry of Natural Resources and Environment MOSTE : Ministry of Science, Technology and Environment MOT : Ministry of Transport MRTA : Mass Rapid Transit Authority MWA : Metropolitan Waterworks Authority IX Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Abbreviations NCDC : National Civil Defense Committee NDPMC : National Disaster Prevention and Mitigation Committee NDWC : National Disaster Warning Center, MICT NEPC : National Energy Policy Committee NESDB : Office of National Economic and Social Development Board NHA : National Housing Authority NSCT : National Safety Council of Thailand NSO : National Statistic Office ONEP : Office of Natural Resources and Environmental Policy and Planning OIC : Office of Insurance Commission OTP : Office of Transport and Traffic Policy and Planning, MOT PEA : Provincial Electricity Authority PTT : PTT Public Company Limited PWA : Provincial Waterworks Authority RFD : Royal Forest Department RID : Royal Irrigation Department, MOAC RTSD : Royal Thai Survey Department, Royal Thai Army SLA : Social Local Administration SRT : State Railway of Thailand TAO : Tambon Administration Organization TMD : Thai Meteorological Department, MICT TRD : Treasury Department, MOF TTD : Traffic and Transport Department, BMA UDA : Urban Development Authority WQM : Water Quality Management Office, BMA International Organization / Agencies ADB : Asian Development Bank AIT : Asian Institute of Technology APN : Asia-Pacific Network for Global Change Research CAPaBLE : Scientific Capacity Building/Enhancement for Sustainable Development DHI : Danish Hydraulic Institute ECLAC : Economic Commission for Latin America and the Caribbean IPCC : Intergovernmental Panel on Climate Change JBIC : Japan Bank for International Cooperation JICA : Japan International Cooperation Agency START : The Global Change System for Analysis, Research, and Training UNDP : United Nations Development Programme USOM : United States Operation Mission WB : World Bank Others B.E. : Buddhist Era BMR : Bangkok Metropolitan Region DEM : Digital Elevation Model DSM : Demand-side Management ENCON : Energy Conservation Promotion GDP : Gross Domestic Product GHG : Greenhouse Gas GIS : Geographical Information System IPP : Independent Power Producer MAGICC : Model for the Assessment of Greenhouse-gas Induced Climate Change MRT : Mass Rapid Transit SCADA : Supervisory Control and Data Acquisition SLR : Sea Level Rise X Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Abbreviations SPP : Small Power Producer SRES : Special Report on Emissions Scenarios VSPP : Very Small Power Producer Units of Measurement mm : millimeter (s) cm : centimeter (s) m : meter (s) km : kilometer (s) m2 : square meter (s) km2 : square kilometer (s) rai : 0.16 hectare m3 : cubic meter (s) MCM : million cubic meters Ml : million litters Mkg : million kilograms sec : second (s) d : day (s) yr : year (s) GWh : gigawatt-hour kV : kilovolt (s) MVA : megavolt-ampere mm/sec : millimeter per second m3/sec : cubic meter per second Baht : Thai baht (Thai currency) MBaht : million Thai baht US$ : United States dollar MSL : mean sea level o : degree ′ : minute ″ : second % : percent o C : degree centigrade UTC : Coordinated Universal Time Mcf : 1000 cubic feet bbl : barrels of oil ktoe : kiloton oil equivalent hPa : hectopascal XI APPENDIX H SEA LEVEL RISE AND STORM SURGE Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix H: Sea Level Rise and Storm Surge APPENDIX H SEA LEVEL RISE AND STORM SURGE H1 SEA LEVEL RISE During the 20th century, global tide gauges indicate global sea level has risen between 1 to 2 mm/year (Figure H1-1). The rising rate varies with location. According to IPCC (3rd Assessment Report), the sea level rise projection simulated by the Model for the Assessment of Greenhouse-gas Induced Climate Change (MAGICC) simple climate model is displayed in Figure H1-2. Simulations were conducted assuming low, medium, and high rates of ice melt in response to global warming. The MAGICC was used to simulate sea level rise from 7 global climate models, spanning a range of sensitivities (1.7-4.20C). Results suggest increase in global sea level of 3-16 cm by 2030, 7-50 cm by 2070, and 9-87 cm by 2100. Source: Crown, 2004 cm/year Figure H1-1 Observed Sea Level Rise during the 20th Century Table H1-1 Projected Global Average Sea Level Rise Sea Level Rise Scenario Mean Value (m) B1 0.18-0.38 0.28 A1T 0.20-0.48 0.33 B2 0.20-0.43 0.32 A1B 0.21-0.48 0.35 A2 0.23-0.51 0.37 A1FI 0.26-0.59 0.43 Source: IPCC AR4, 2007 Source: CSIRO, 2006 Figure H1-2 Projected Sea Level Rise for 6SRES A refined result was made by the IPCC 4th Assessment Report (IPCC AR4, 2007) which indicates the sea level rise for six SRES marker scenarios as given in Table H1-1. Table H1-1 is based on thermal expansion and ice melt; these estimations show acceleration up to 2.4 times compared to the 20th century. The rise in sea level mentioned above will cause significant impacts on the delta communities which are widely recognized as highly vulnerable areas. Most deltas are already undergoing natural subsidence that results in accelerated rates of relative sea level rise above the global average. Many rivers are impacted by the effects of water extraction and diversion, as well as declining sediment input as a consequence of entrapment in dams. Delta plains, particularly those in Asia, are densely populated and large numbers of people are often impacted as a result of external terrestrial influences (river flood, sediment starvation) and/or external marine influences (storm surge and erosion). H-1 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix H: Sea Level Rise and Storm Surge Ericson et al. (2006) estimated that more than 1 million people will be directly affected by 2050 in three mega deltas: the Ganges-Brahmaputra delta in Bangladesh, the Mekong delta in Vietnam and the Nile delta in Egypt. More than 50,000 people are likely to be directly impacted in each of a further 12 deltas (Figure H1-3). Remark: Extreme: > 1,000,000 High: 50,000-1,000,000 Medium: 5,000-50,000 Source: Ericson et al., 2006 Figure H1-3 Relative Vulnerability of Coastal Deltas (2050) It was also found that 75% of the population affected live on Asian deltas. Within the Asian deltas, the surface topography is complex as a result of the geomorphological development of the deltas, and the population distribution shows considerable spatial variability, reflecting the intensive land use and the growth of the world’s largest cities (Woodroffe et al., 2006). Many people in these deltas worldwide are already subjected to flooding from both storm surges and seasonal river floods, and therefore it is necessary to develop further methods to assess individual delta vulnerability (Sanchez-Arcilla et al., 2006). In summary, the IPCC 4thAssessment Report indicated the following impacts to Thailand (Considering only impacts from sea level rise): 1) Loss of land due to sea level rise between 50 to 100 cm could decrease the national GDP 0.36% to 0.69% (300 to 600 US$) per year, respectively; 2) Projected severe flood risk with sea level rise. The population exposed to flooding by storm surges will increase over the 21st century. Asia dominates the global exposure with its large coastal population: Bangladesh, Vietnam, and Thailand having serious coastal flooding; 3) Even under the most conservative scenario, sea level will be about 40 cm higher than today by the end of 21st century and this is projected to increase the annual numbers of people flooded in coastal populations from 13 million to 94 million. About 20% will occur in south-east Asia, especially from Thailand to Vietnam including Indonesia and Philippines; and 4) The cause of direct damage in Asia caused by the tropical cyclones has increased more than 5 times in the 1980s compared to the 1970s and about 35 times more in the early 1990s than in 1970s. Flood-related damages also increase by about 3 times and by 8 times respectively in the 1990s in relation to those in the 1980s and 1970s. These trends are likely to persist in the future. H-2 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix H: Sea Level Rise and Storm Surge Somboon (1992) showed that the shoreline has migrated about 90 to 100 km southward from the center of the central plain in Thailand over the last 6,000 years, which corresponds to a migration rate of about 15 km2/year. Saito et al. (2000a) also studied delta-front migration of the Chao Phraya River. Radiocarbon dates from deltaic sediments indicate a migration rate of 20 km2/year for the last 4,000 years. Moreover, based on a reconstructed map of the paleo-delta front in the central plain in Thailand, they calculated the approximate paleosediment discharge of the river system to the northern part of the Gulf of Thailand. It is estimated that the average sediment volume for the last 3,000 years (on a 1,000-year timescale) was about 20 MCM/year (land increment of 2,000 km2, thickness of 10 m, and duration of 1,000 years). This value was almost equivalent to the present sediment-discharge rate of the Chao Phraya and the Mae Klong Rivers. Recent topographic maps and satellite images show a rapid shoreline retreat because of coastal erosion at the mouth of the Chao Phraya River. The western shore of the river's mouth lost 1.8 km2 between 1969 and 1973, 1.5 km2 between 1973 and 1979, and 3.9 km2 between 1979 and 1987, for a maximum shoreline retreat of 500 m between 1969 and 1987 (Vongvisessomjai et al., 1996). Moreover, Okubo et al. (2000) showed that the shoreline retreated 200 to 300 m between 1987 and 1992. Major changes stopped by 1992, because there is no change in the satellite images between 1992 and 1998. The total shoreline retreat since 1969 based on a topographic map of that date and satellite images was 700 m. The major reason for this rapid shoreline retreat is thought to be land subsidence due to groundwater pumping. In the city of Bangkok and its vicinity, land subsidence has been a critical issue since 1978. The Royal Thai Survey Department (RTSD) reviewed benchmarks to evaluate general land subsidence in Bangkok in 1978 and found a variable degree of subsidence, ranging from 20 to 85 cm between 1930 and 1978. This land subsidence continued actively in the 1980s. Total subsidence of Bangkok up to 1988 ranged from less than 20 cm to more than 160 cm, with a maximum rate of 12 cm/year. This subsidence occurred in the coastal and river-mouth areas of the Chao Phraya River with amount of 20 to 30 cm between 1978 and 1987. This means the relative sea level rise at a rate of 2 to 3 m in 100 years, which is higher than the predicted rate of sea level rise in the 21st century from global warming. In addition, no coastal erosion has been recognized. Both rivers have dams upstream, and sand is dredged in both channels. The only difference between the two is subsidence, and coastal erosion has been recognized only where the coastal area is subsiding. Land subsidence occurred not only onshore but also offshore. The slope of the near shore zone of the Chao Phraya River Delta is very gentle with a gradient of 1 m/km. Therefore, a subsidence of 10 to 20 cm induced an increase of 10% to 20% in water depth at a point 1 km offshore and an increase of 5% to 10% 2 km offshore. This increase in water depth is the main cause of the increase in wave energy resulting in coastal erosion (Saito et al., 2000b). Moreover the cutting of mangroves along the coast accelerated the shoreline retreat. In the South China Sea, the rate of Sea Level Rise (SLR) has been studied by several researchers. Ding et al. (2004) found a rising rate of SLR of 2.2 ± 0.2, 2.5 ± 0.2 mm/year for Hong Kong and along the Eastern China. Nguyen (2004) found also a rising SLR of 2.3 ± 0.6 mm/year along Vietnam coastline. The Department of Survey and Mapping of Malaysia (2001) found also a rising SLR of 2.4 ± 0.5 mm/year. Sommart and Itthi (2007) analyzed the trend of local sea level rise for Thailand. By using annual averaged data from 3 tide gauge stations of the Hydrographic Department and 1 tide station from the Port Authority of Thailand, it found different rates among stations: Sattahip 0.22 mm/year, Ko Mattaphon 0.51 mm/year, Ko Sichang 0.81 mm/year and Ko Lak 0.52 mm/year. The relative sea level rise in Thailand is shown in Figure H1-4. H-3 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix H: Sea Level Rise and Storm Surge Source: Sommart and Itti, 2007 Figure H1-4 Relative Sea Level Rise in Thailand by Sommart and Itti (2007) Supharatid (2007) analyzed the tidal records obtained from the Marine Department at several stations along the coastline of Thailand; the yearly averaged values are plotted in Figure H1-5. Chao Phraya Tha Chin Bang Pakong Mae Klong Chan Thaburi Ranong Si Chon Krabi Narathivat Source: Supharatid, 2007 Figure H1-5 Relative Sea Level Rise in Thailand by Supharatid (2007) It was found that in general the rate of relative sea level rise around Thailand coastline varies depending on location. In the Upper Gulf of Thailand (Samut Songkram, Samut Sakhon, Bangkok, and Samut Prakarn), the relative sea level rise is about 1-2 cm/year. The average value is 1.3 cm/year implying 3 mm/year rate of sea level rise considering land subsidence rate of 1 cm/year. In the eastern coast (Chanthaburi, Rayong, and Trat), the SLR is about 2-3 mm/year. In the southern east coast (Pattani, Songkhla, Nakhon Si Thammarat, Surat Thani, and Chumphon), the SLR varies from 3 to 5 mm/year. In the southern west coast (Ranong, Phuket, and Krabi), the sea H-4 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix H: Sea Level Rise and Storm Surge level rise varies from 5 to 10 mm/year. Therefore, the most vulnerable area is the Upper Gulf of Thailand. Effect of the future sea level rise is one of the serious problems in the low and flat deltaic regions of Southeast Asia, and the issues of sea level rise are also being considered on the Chao Phraya River Delta (Somboon and Thiramongkol, 1993; Sabhasri and Suwarnarat, 1996). Geo- environments of the Chao Phraya River Delta are very susceptible to sea level rise. It is assumed that sea level rise influences the regions of the delta in various ways (Umitsu, 2006). Elevation of tidal plain is 1-2 m and the rn The tidal plain is transformed to l o n gk o aquaculture ponds sediments of the area a ittay consist of very soft silt or P ng K h lo n clay. This elevation is K h l o almost the same as the g K hun high tide level of the Gulf of Thailand. In some Khlong Loa n g Racha places, land was reclaimed 1-2 m over the original p in ij surface, but most area of Average Mangrove Belt Width = 50 m Scenic Viewpoint the tidal plain is not reclaimed and is used as o f B M A p in g L ine aquaculture ponds and salt Boundary Pole um R o ck D pans. Now, the mangrove Boundary Pole belt is approximately 50 m wide (Figure H1-6). Source: BMA, 2007a Figure H1-6 Aerial Photo of the Upper Gulf of Thailand In particular, the embankments that are surrounding the tidal plain are low and weak condition, and they are vulnerable to coastal erosion. Actually, in the western part of the Chao Phraya River Mouth, rapid coastal erosion is now going on, and protection for coastal erosion in the area is not enough (Vongvisessomjai et al, 1996). If sea level rise occurs in the future, severe coastal erosion will be the most serious problem in the area. Even if sea level rise is less than 50 cm, horizontal retreat of the shoreline will be a considerable distance from the present coast. Under the weak protection for the coastal embankment, coastal erosion may progress very rapidly. Soft silt and clay deposits of this area also accelerate rapid erosion. On the other hand, the area of deltaic tidal plain is located on the inner side of the delta, but the area is also low-lying and has little relief. This environment will also be easily affected by sea level rise. Serious subsidence has occurred in this area, and the current ground level has been lowered to 1- 2 m (last 8 years: 20 cm subsidence at Bang Khun Thian, Figure H1-7). Subsidence of 1 cm might cause an erosion of approximately 10 m if the slope of the foreshore is 1:1,000 m. In several places, the ground level is lower than the present mean sea level. Therefore, drainage condition of the area has become very poor, and flooding may occur easily in the rainy season. Several researchers have already discussed about land subsidence of the area, and they also pointed out the problem in relation to sea level rise. Acceleration of the already poor drainage conditions is anticipated in the deltaic tidal plain because the surface gradient of the region is very low and the relative gradient of the drainage is going to decrease as a result of sea level rise. As there is little high ground in the deltaic tidal plain region except the artificial reclaimed land, the impact of sea level rise may greatly affect the region. Land subsidence also accelerates the effect. H-5 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix H: Sea Level Rise and Storm Surge Source: BMA, 2007a Figure H1-7 Land Subsidence on the Chao Phraya River Delta H2 STORM SURGE The storm level and storm surge is the most dangerous part of typhoon causing serious coastal flooding. When the wind blows over the ocean, it causes the ocean water to pile up and push the water into the continental shelf or coastline. The height of the surge is basically measured as a deviation from the mean sea level in the area and in some historical storms; this value has reached over 6.1 m. In the Gulf of Thailand, three storm surges occurred in the recent past. In 1962, the storm surge accompanying tropical storm Harriet caused severe impacts on the Lame Taloom Pook peninsula in Southern Thailand. More than 900 people were killed. In 1989, typhoon Gay also produced storm surge and attacked the eastern coast of Chumphon and along the Rayong coast in the inner Gulf area. In 1997, typhoon Linda originated in the South China Sea and upgraded to typhoon intensity shortly after entering the Gulf of Thailand. (Figure H2-1). The cyclone turned northwestward following steering from the subtropical ridge. Typhoon Linda caused strong winds and heavy rainfall. A significant wave height of 3-4 m was measured (Figure H2-2). Linda weakened slightly to a wind velocity of 50 knots before it made landfall in Thabsakea, Prachuap Khiri Khan province. (Figure H2-3). Source: TMD, 2007 Figure H2-1 Typhoon Linda from GMS-05 Satellite Image H-6 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix H: Sea Level Rise and Storm Surge Source: TMD, 2007 Figure H2-2 Buoy Location in the Gulf of Thailand Source: TMD, 2007 Figure H2-3 Typhoon Linda Track During the passage of typhoon Linda, strong winds were experienced north of the typhoon track. The mean sea level pressure was only in the order of 5 hPa lower than the surrounding pressure. Consequently, the storm surge that was noticed along the coastline north of the standing point was due to strong onshore wind, piling up the water mass. The maximum storm surge was estimated to be 0.61 m due to the wind stress (Watana, 2005). Data observations and simulation results using the WAM model revealed the following results: H-7 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix H: Sea Level Rise and Storm Surge Bathymetry grid is taken from World Elevation Data (ETOPO5) covering the region 95°E to 105°E and 5°N to 15°N (Figure H2-4) with 0.25 degree resolution in both latitude and longitude (41 x 41 grids). The initially employed wind data (from NOGAPS Model archives) were provided by the Naval Research Laboratory Monterey (NRLMRY). The winds are from the period 00Z 1-8-97 to 00Z 31-12-97, with 1.0° resolution and are linearly interpolated to specify wind components at each wave grid point. From November 1–4, 1997, strong northeasterly winds associated with a significant tropical cyclone activity were observed in the Gulf of Thailand. The wind speed reached up to 22 m/sec over the area of study. Wave data were obtained from 3 moored buoys (HHN, KCH, and KSI stations) of Geo-Informatics and Space Technology Development Agency (GISTDA) and 1 automatic marine meteorological station (UNC station). Remark: HHN-Hua Hin, KSI-Koh Sichang, KCK-Koh Chang, UNC-Unocal Source: Watana, 2005 Figure H2-4 Study Location The wave hind casting was carried out using 12 directional bands, 25 frequency bands and frequency interval extending from 0.042 to 0.41 Hz. A 5 minutes time step has been used for the integration of advection and source terms, considering depth refraction. The output time step was 6 hours and a JONSWAP spectrum was selected as an initial condition. The wind data from November 1–4, 1997 was used to investigate the generated wave fields under the typhoon event. Wind fields, significant wave heights and peak wave periods are shown every 6 hours from Figure H2-5 to H2-8. The wind and wave directions are plotted using the meteorological convention with arrows every 10 grid points. Figure H2-5 shows the wind input (NOGAPS), characterized by the speed and direction. On November 3, 1997, the wind field at 00 UTC was uniform along the shoreline with speeds of approximately 10 m/sec. The simultaneous wave fields displayed 2.0 m height with the maximum of 3.6 m near the storm center. Six hours later (at 06 UTC), the wind fields became better organized with a speed of 12 and 18 m/sec along the shoreline and near the storm center, respectively. The storm still kept moving to the west and hit the landfall at 18 UTC. The wave of about 4.5 m height was observed near the shoreline. Generally, the wave fields follow the wind patterns rather well. Comparing the wind fields from Figure H2-5 and wave fields from Figure H2-6 indicates that the spatial variability is closely related. The maximum heights are associated with the maximum wind speeds. A sequence of peak wave period is shown in Figure H2-7. On November 3, during the first 6 hours, the region of simulation was characterized by mainly sea waves. Under the strong north- east wind 9 seconds swell was generated and distributed along the south coast. It reached the UNC station at 00 UTC. This swell was further adverted to the north, arriving at the HHN station with 10 seconds peak wave periods at 12 UTC. Six hours later it reached the upper region. H-8 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix H: Sea Level Rise and Storm Surge Source: Watana, 2005 Figure H2-5 Wind Fields on November 3 , 1997, every 6 hours (NOGAPS) Source: Watana, 2005 Source: Watana, 2005 Figure H2-6 Wave Fields in November Figure H2-7 Peak Wave in November 3, 1997 every 6 hours (WAM output) 3, 1997 (WAM output) H-9 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix H: Sea Level Rise and Storm Surge Figure H2-8 shows comparison of wave height and wave period time series at the HHN station. In general, the modeled wave heights underestimate the observed wave heights especially in extreme case. This amounts to an underestimation as much as 20%. The wave buoy reported the maximum of 4.06 m significant wave height, whereas the simulated value is approximately 3.2 m at 06 UTC on November 3, 1997. Difference of nearly 1 m wave height can be attributed to: 1) The limited "local" quality of the wind field (since the NOGAPS wind data correspond to a grid size of 1.0° resolution while the WAM model grid size is 0.25°); and 2) The enhanced energy dissipation due to the centered differences used in the model and the relatively close presence of a "diagonal" boundary. The comparison in term of the time series peak wave period also reveals that from the beginning of the simulation to 481 hours there were mainly sea waves. After this time the peak period increased to 6 s (Buoy data) and 7.4 s (WAM), denoting a clear effect of typhoon Linda winds on swell waves. a) Wave height b) Peak wave period Source: Watana, 2005 Figure H2-8 Time Series of Wave Parameters at HHN Station In addition, the measured water level at 4 river mouth stations in the Upper Gulf of Thailand (Figure H2-9) showed highest records on November 4, 1997 as given in Figure H2-10. Tha Chin This indicates that Linda Chao Phraya caused storm surges (in the circles) as approaching the Mae Klong Bang Pakong Upper Gulf of Thailand at the Mae Klong, Tha Chin, Chao Phraya, and Bang Pakong river mouths. Source: BMA, 2007a Figure H2-9 Tidal Stations in the Upper Gulf of Thailand H-10 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix H: Sea Level Rise and Storm Surge 3 2.5 2 Water level (msl) 2 1.5 ater level(msl) 1 1 0.5 0 0 W 0 100 200 300 400 500 600 700 -1 0 -0.5 200 400 600 800 -1 -2 -1.5 Hours Hours a) Mae Klong b) Tha Chin 3 3 2 Water level (msl) 2 1 Wter level(msl) 1 0 0 -1 0 200 400 600 -1 0 100 200 300 400 500 600 -2 -2 Hours Hours c) Chao Phraya d) Bang Pakong Source: MD, 2007 Figure H2-10 Water Levels on Nov. 4, 1997 H-11 APPENDIX I LAND SUBSIDENCE Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix I: Land Subsidence APPENDIX I LAND SUBSIDENCE I1 PROBLEMS Since 1953, Bangkok and its perimeter have developed groundwater use for consumption and industry. Due to over pumping of groundwater, a groundwater crisis takes place. Its indicator is a rapid drawdown of piezometric level without any recovery resulting in land subsidence and seawater intrusion in aquifers where fresh water becomes brackish water or salt water. Owing to land subsidence, drainage pipes are inundated, water supply pipes are damaged and roads and pavements are cracked, etc. As a consequence, it leads to an economic loss and affects the quality of people’s life. The Department of Groundwater Resources (DGR, formerly Department of Mineral Resources) is mainly responsible for damages relating to groundwater resources, environment and its impacts. The following measures are carried out to prevent its damages: I1.1 Legal Prevention and Mitigation Measures 1) Drafted the Groundwater Act B.E.2520 (1977) to control the groundwater business and the drainage to groundwater wells; 2) Designated 3 critical groundwater zones according to the cabinet resolution dated March 15, 1983 (Figure I1.1-1) comprising 4 provinces: Bangkok, Nonthaburi, Pathum Thani, and Samut Prakarn: (1) Critical Zone 1 covers areas of land subsidence of more than 10 cm/year and/or an area of rapid drawdown, (2) Critical Zone 2 covers areas of land subsidence of 5-10 cm/year and/or an area of high drawdown, and (3) Critical Zone 3 covers areas of land subsidence of less than 5 cm/year and an area of low drawdown. The above measures stipulated that the government agencies should stop using groundwater for water supply in critical zones 1 and 2 whereas the private sector should reduce its consumption in different periods of time. Moreover, DGR is assigned to monitor the groundwater level every month and the Royal Thai Survey Department (RTSD) is assigned to measure the land subsidence every year; 3) Expanded the critical zones into 3 more provinces: Nakhon Pathom, Samut Sakhon, and Phra Nakhon Si Ayutthaya according to the cabinet resolution on May 23, 1995 (Figure I1.1-2) and announced the new critical zones covering 7 provinces: (1) Critical Zone 1 covers areas of land subsidence of more than 3 cm/year and drawdown more than 3 m/year, (2) Critical Zone 2 covers areas of land subsidence of 1-3 cm/year and drawdown 2-3 m/year, and (3) Critical Zone 3 covers areas of land subsidence of less than 1 cm/year and drawdown less than 2 m/year; 4) Amended the Groundwater Act B.E.2520 (1977), Amendment No.2, B.E.2535 (1992) and Amendment No.3, B.E.2546 (2003) for more efficient management of groundwater. Consequently, the groundwater consumption in Bangkok and its perimeter was obviously reduced; and 5) Announced the ministerial regulations of the Ministry of Natural Resources and Environment (MONRE) dated July 30, 2003 on the latest critical zones comprising 7 provinces: Bangkok, Samut Prakarn, Pathum Thani, Nonthaburi, Samut Sakhon, Phra Nakhon Si Ayutthaya, and Nakhon Pathom. I-1 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix I: Land Subsidence 1620000 600000 630000 660000 690000 1620000 Ang Thong ! P Saraburi P ! Suphan Buri P ! 1590000 1590000 ! P Phra Nakhon Si Ayutthaya 1560000 1560000 P ! Pathum Thani Nonthaburi P ! 1530000 1530000 P ! Nakhon Pathom ! P Bangkok P ! 1500000 1500000 Samut Prakarn Ratchaburi Samut Sakhon P ! ! P Samut Songkham G u l f o f T h a i l a n d ! P 600000 630000 660000 690000 Legend P ! Province Groundwater Critical Zone (1983) P:\0816\Map Project\054-แผนที่ groundwater-1983-a4-รายงาน TWM 050252 Province Boundary Zone 1 (Land Subsidence > 10 cm./y) District Boundary Main Road Zone 2 (Land Subsidence 5 - 10 cm./y) Zone 3 (Land Subsidence < 5 cm./y) 0 3 6 Ê 12 18 24 Kilometers Water Body Non Critical Zone Source: DGR, 2007 Figure I1.1-1 Critical Groundwater Zone Map (1983) I-2 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix I: Land Subsidence 1620000 600000 630000 660000 690000 1620000 Ang Thong ! P Saraburi P ! Suphan Buri P ! 1590000 1590000 ! P Phra Nakhon Si Ayutthaya 1560000 1560000 ! P Pathum Thani Nonthaburi P ! 1530000 1530000 P ! Nakhon Pathom ! P Bangkok P ! 1500000 1500000 Samut Prakarn Ratchaburi Samut Sakhon P ! ! P Samut Songkham G u l f o f T h a i l a n d P ! 600000 630000 660000 690000 Legend P ! Province Groundwater Critical Zone (1995) P:\0816\Map Project\054-แผนที่ groundwater-1995-a4-รายงาน TWM 050252 Province Boundary Zone 1 (Land Subsidence > 3 cm./y) District Boundary Main Road Zone 2 (Land Subsidence 1 - 3 cm./y) Zone 3 (Land Subsidence < 1 cm./y) 0 3 6 Ê 12 18 24 Kilometers Water Body Source: DGR, 2007 Figure I1.1-2 Critical Groundwater Zone Map (1995) I-3 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix I: Land Subsidence I1.2 Economic Prevention and Mitigation Measures 1) Collected groundwater fee on February 3, 1985 in 6 provinces: Bangkok and its perimeter except Nakhon Pathom at 1.00 baht/m3; 2) Increased to 3.50 baht/m3 on July 1, 1994 and as of January 18, 1995 used the same rate throughout the country; 3) Increased from 3.50 to 8.50 baht/m3 only in Bangkok and its perimeter and Nakhon Pathom (7 provinces) on August 1, 2000 and gradually increased by 0.50 baht in every quarter; and 4) Collected a groundwater conservation fee in critical zones in 7 provinces comprising Bangkok, Samut Prakarn, Pathum Thani, Nonthaburi, Samut Sakhon, Phra Nakhon Si Ayutthaya, and Nakhon Pathom at 0.85 baht/m3 with no exception nor reduction in all water supply and non-water supply areas on September 1, 2004 and increased by 1.00 baht in every quarter until it reached 8.50 baht on July 1, 2006. I1.3 Technical Prevention and Mitigation Measures A network of groundwater monitoring wells and land subsidence benchmarks have been arranged to study the land subsidence and monitor the groundwater level and its quality since 1978. The network consists of DGR, AIT, and RTSD in coordination with the National Environmental Committee. Observation wells at different aquifers were drilled and benchmarks were arranged to study the expansion of aquifers, soil and rock layers, and change 1,620,000 in groundwater level and land subsidence. First, Bangkok and inner areas were focused 1,600,000 including outer areas: Nonthaburi, Pathum Thani, and Samut Prakarn. The study from 1,580,000 1978 to 1982 found that groundwater was widely used and the groundwater level dropped 1,560,000 rapidly, besides land subsidence occurred. Therefore, prevention and mitigation groundwater 1,540,000 measures were formulated by designating critical zones, controlling groundwater 1,520,000 consumption according to the Groundwater Act B.E.2520 (1977) and expanding the 1,500,000 network of observation wells and benchmarks to Nakhon Pathom, Phra Nakhon Si Ayutthaya, and 1,480,000 580,000 600,000 620,000 640,000 660,000 680,000 700,000 720,000 Samut Prakarn. At present, there Office of Natural Resources and Environmental Policy and Planning (ONEP) = 38 bench marks Royal Thai Survey Department (RTSD) = 33 bench marks are 143 stations of monitoring Department of Groundwater Resources (DGR) = 29 bench marks wells, 456 wells and 70 DGR Monitoring wells, 143 stations (456 wells) (RTSD, 2007 and DGR, 2007) benchmarks (Figure I1.3-1). Source: DGR,2007 and RTSD, 2007 Figure I1.3-1 Land Subsidence Benchmarks and Monitoring Wells I-4 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix I: Land Subsidence I2 PRESENT SITUATION Situation of land subsidence in Bangkok and adjacent areas (2007) is presented in Figure I2-1. Source: RTSD, 2007 Figure I2-1 Land Subsidence in Bangkok and Adjacent Areas (2007) I-5 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix I: Land Subsidence Following various measures by the DGR to cope and prevent groundwater and land subsidence crisis due to groundwater overuse, land subsidence has been reduced and the groundwater level has been significantly recovered as follows: 1) Pathumwan, Bangkok: The land subsidence rate from 1978 to 1985 was 3.2 cm/year but only 0.8 cm/year from 2003 to 2007. The lowest groundwater level was 37 m below ground in 1997 and 27 m below ground in 2007 (Figure I2-2); 2) Ramkhamhaeng University (Hua Mak, Bangkok): The land subsidence rate was 10 cm/year from 1978 to 1985 and 1.2 cm/year from 2003 to 2007. The lowest groundwater level was 54 m below ground in 1996 and 30 m in 2007; 3) Lat Kraban (Minburi, Bangkok): The land subsidence rate was 3.4 cm/year from 1978 to 1999 and only 0.2 cm/year from 2003 to 2007. The lowest groundwater level was 69 m below ground in 1997 and 39 m in 2007; 4) Bangkok’s eastern perimeter (Bang Phli, Samut Prakan): The land subsidence rate was 5.7 cm/year from 1986 to 1998 and 1.8 cm/year from 2003 to 2007. The lowest groundwater level was 51 m below ground in 1979 and 30 m in 2007; 5) Bangkok’s northern perimeter (Muang Pathum Thani): The land subsidence rate was 0.3 cm/year from 1986 to 2002 and 2.8 cm/year from 2003 to 2005. At present, it is 0.65 cm/year (2006-2007). The lowest groundwater level was 33 m below ground in 1997 and 24 m in 2007; and 6) Bangkok’s western perimeter (Muang Samut Sakhon): The land subsidence rate was 1.0 cm/year from 1979 to 1989 and 2.4 cm/year from 1990 to 1997. At present, it is 1.3 cm/year (2003-2007). The land subsidence situation is slightly better but still high. The lowest groundwater level was 82 m below ground in 1999 and 60 m in 2007. However, MONRE and DGR strictly monitor the use of groundwater. Relationship between Land Subsidence and Ground Water Level If the groundwater use is higher, the groundwater level will be lower and land subsidence will be higher. Figure I2-3 shows the relationship between land subsidence and groundwater level of monitoring wells in Hua Mak Golf Course, Bangkok. The red line shows the quantity of groundwater use whereas the blue line shows the groundwater level of Phra Pradaeng Aquifer, the purple line of Nakhon Luang Aquifer, the green line of Nonthaburi Aquifer and the brown line show the land subsidence. Between 1997 and 1999, the maximum groundwater use was 2.4-2.5 MCM/day. The lowest groundwater level of Nonthaburi Aquifer was approximately 54 m and the accumulated subsidence rate was below -100 cm. However, some areas subsided despite no groundwater use, eg, Khlong Dan district, Samut Prakarn province. But the stoppage of groundwater use may not stop the land subsidence in Bangkok and its surrounding areas due to delta deposits (soft clay). After 1999, the groundwater use, groundwater level, and land subsidence were likely to be better as a result of the announcement of groundwater use zones. In addition, the DGR has collected groundwater conservation fees to solve groundwater problems in Bangkok and its perimeter. The data on land subsidence from the mean sea level at Ramkhamhaeng University in Figure I2-3 shows that after 1977 the land subsidence tended to decrease when groundwater use was reduced. The land subsidence was approximately 1 cm/year (2006-2007). I-6 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix I: Land Subsidence Correlation Between Subsidence and Groungwater Level Correlation Between Subsidence and Groungwater Level at Chula longkorn University, Pathumwan, Bangkok at Ram Kham Heang University, Bang Kabi, Bangkok 0 0 0 0 Bangkok Aquifer (50 m depth) Bangkok Aquifer (50 m depth) Bench mark : CI.8-1 5 10 Phra Pradeang Aquifer (100 m depth) Phra Pradeang Aquifer (100 m depth) 5 10 Bench mark : CI.10-1 10 Phra Pradeang Aquifer (100 m depth) 20 Nakhon Luang Aquifer (150 m depth) 15 Nonthaburi Aquifer (200 m depth) 30 10 Nonthaburi Aquifer (200 m depth) 20 Accumulated Land Subsidence D e p th to W a te r b e lo w L a n d S u r fa c e , in m . 20 BK0003 40 D e p th to W a te r b e lo w L a n d S u rfa c e , in m . Accumulated Land Subsidence 15 30 PD0005 25 50 B e n c h m a rk A ltitu d e , in c m . B e n c h M a rk A ttitu d e ,in c m . 30 60 20 40 PD0017 BK0002 35 70 NL0011 25 50 40 80 NL0034 45 90 30 60 NB0027 50 NB0008 100 35 70 55 110 60 120 40 80 65 130 70 140 45 90 75 150 50 100 80 160 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 Year Year a) Pathumwan, Bangkok b) Bang Kapi, Bangkok Correlation Between Subsidence and Groungwater Level Correlation Between Subsidence and Groungwater Level at Min Buri Office, Min Buri, Bangkok at Bang Phli Rat Bom Lung School, Bang Phli, Samut Prakan 0 0 0 0 Bangkok Aquifer (50 m depth) Bench mark : CI.30-1 Bench mark : CI.28-1 5 Phra Pradeang Aquifer (100 m depth) 10 20 Nakhon Luang Aquifer (150 m depth) 10 20 JICA0008(BK) Nonthaburi Aquifer (200 m depth) 15 Accumulated Land Subsidence 20 PD0040 40 D e p th to W a te r b e lo w L a n d S u rfa c e , in m . D e p th to W a te r b e lo w L a n d S u rfa c e , in m . 20 40 BK0003 B e n c h m a rk A ltitu d e , in c m . B e n c h m a rk A ltitu d e , in c m . 25 30 60 PD0012 NB0029 NB0046 30 60 NL0016 40 80 35 NL0037 40 80 50 100 Bangkok Aquifer (50 m depth) 45 Phra Pradeang Aquifer (100 m depth) 50 100 60 Nakhon Luang Aquifer (150 m depth) 120 55 Nonthaburi Aquifer (200 m depth) Accumulated Land Subsidence 60 120 70 140 65 80 160 70 140 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 Year Year c) Min Buri, Bangkok d) Bang Phli, Samut Prakarn Correlation Between Subsidence and Groungwater Level Correlation Between Subsidence and Groungwater Level at Pathum Thani Provincial Hall, Muang, Pathum Thani at , Samut Sakhon Provincial Hall, Muang, Samut Sakhon 0 0 0 0 Bench mark : CI.35-1 JICB0005(BK) Bench mark : CI.32-1 5 10 10 20 10 20 20 40 PD0019 D e p th to W a te r b e lo w L a n d S u rfa c e , in m . D e p th to W a te r b e lo w L a n d S u rfa c e , in m . 15 30 30 60 B e n c h m a rk A ltitu d e , in c m . B e n c h m a rk A ltitu d e , in c m . PD0047 JICC0004(NB) 20 40 40 80 NL0065 JICC0003(NL) Bangkok Aquifer (50 m depth) 25 50 50 100 Bangkok Aquifer (50 m depth) NB0064 Phra Pradeang Aquifer (100 m depth) 30 Phra Pradeang Aquifer (100 m depth) 60 60 120 Nonthaburi Aquifer (200 m depth) Nakhon Luang Aquifer (150 m depth) 35 70 70 Nonthaburi Aquifer (200 m depth) 140 Nonthaburi Aquifer (200 m depth) Accumulated Land Subsidence Accumulated Land Subsidence 40 80 80 160 45 90 90 180 50 100 100 200 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 Year Year e) Muang, Pathum Thani f) Muang, Samut Sakhon Source: DGR, 2007 and RTSD, 2007 Figure I2-2 Correlation between Land Subsidence and Groundwater Level I-7 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix I: Land Subsidence Land Subsidence at Ramkamhang University and Groundwater level from monitoring well at Hua Mak Golf Course, Bangkok 3.0 10 0 Phra Pradeang Aquifer (100 m depth) 10 15 Nakhon Luang Aquifer (150 m depth) 2.5 Nonthaburi Aquifer (200 m depth) Groundwater Use ( million cu.m./day) 20 20 Groundwater Level (m. below groung) Land subsidence Accumulate (cm.) 30 25 2.0 40 30 50 1.5 35 60 40 70 1.0 45 80 50 90 0.5 55 100 0.0 60 110 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 20 20 20 20 20 20 20 20 Year Source: DGR, 2007 Figure I2-3 Relationship between Land Subsidence and Groundwater Level I3 FORECAST OF FUTURE LAND SUBSIDENCE The Consultant assessed the land subsidence rate in the past and found that it tended to be gradually reduced from 10 cm/year to 1-2 cm/year as shown in Figure I3-1 and I3-2. It also shows that from 1979 to 2007 the average land subsidence in every 5 years was reduced from 5.32 cm/year to 0.97 cm/year in the last 5 years (2002-2007). Therefore, the consultant selected the average land subsidence rate in the last 5 years to be criteria for future forecast and determined its subsidence rate to be reduced by 10% per year. The above rate is considered based on the land subsidence rate and the groundwater level in the past 10 years (1997-2007). It was found that during that time the groundwater continuously recovered and was in accordance with the annual reduced land subsidence rate by 10% per year. Nowadays, the highest land subsidence rate is approximately 120 cm in front of Ramkhamhaeng University, Bang Kapi District (Figure I3-3). It is expected that the accumulate land subsidence from 2007 to 2050 will amount to 5 to 30 cm (Figure I3-4). 15.0 7 2 7 82 98 99 99 02 07 19 14.0 -1 -1 3-1 20 20 78 - 83 88 9 8- 3- 19 19 13.0 19 9 0 12.0 19 19 20 11.0 10.0 Land subsidence rate (cm/y) 9.0 8.0 7.0 6.0 5.32 5.0 4.0 3.0 2.02 1.89 1.81 2.0 1.39 0.97 1.0 0.0 -1.0 -2.0 -3.0 -4.0 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 Year CI.1-1 CI.7-1 CI.8-1 CI.10-1 CI.11-1 CI.14-1 CI.15-1 CI.16-1 CI.17-1 CI.18-1 CI.19-1 CI.20-1 CI.25-1 CI.28-1 CI.29-1 CI.30-1 CI.31-1 CI.32-1 CI.33-1 CI.34-1 CI.35-1 CI.37-1 CI.41-1 CI.42-1 CI.43-1 CI.44-1 CI.45-1 CI.49-1 CI.50-1 CI.51-1 CI.52-1 CI.53-1 CI.54-1 CI.55-1 CI.56-1 CI.57-1 CI.58-1 CI.59-1 Source: RTSD, 2007 Figure I3-1 Land Subsidence Rate (1979–2007) I-8 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix I: Land Subsidence 1978-1982 1993-1997 1983-1987 1998-2002 1988-1992 2003-2007 Source: RTSD, 2007 Figure I3-2 Average Land Subsidence Rate 1,620,000 1,620,000 1,600,000 1,600,000 1,580,000 1,580,000 1,560,000 1,560,000 1,540,000 1,540,000 1,520,000 1,520,000 1,500,000 1,500,000 1,480,000 1,480,000 580,000 600,000 620,000 640,000 660,000 680,000 700,000 720,000 580,000 600,000 620,000 640,000 660,000 680,000 700,000 720,000 Source: RTSD, 2007 Source: Panya Consultants Figure I3-3 Accumulate Land Subsidence Figure I3-4 Accumulate Land Subsidence (1978-2007) (2007-2050) I-9 APPENDIX J METEOROLOGY AND HYDROLOGY Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix J: Meteorology and Hydrology APPENDIX J METEOROLOGY AND HYDROLOGY J1 GENERAL CONDITION J1.1 Climate The climate of the Chao Phraya River Basin belongs to the tropical monsoon (Figure J1.1-1). The average annual rainfall over the basin is 1,130 mm which ranges from 1,000 to 1,600 mm and it registers higher in the o 100 00 N 105 00o northeastern region of the basin (Figure J1.1- o n 2). According to the 20 00o so o 20 00 M on rainfall pattern, about t e as Feb 85% of the average rth t - No Oc annual rainfall is Trou registered in the period gh between May and Sep an d October Tropical Jun on nso cyclones occur between on Mo o nso a st eb e -F September and October s t M t h and may strike the Chao t hw e Dep r N or Oct u t e ssi o Phraya River Basin. In So - Oc n Ma y Aug a nd this case, rainfall - Se Ty p continues for a long p hoo n period of time in a 15o00 Thailand 15o00 relatively wide area due Troug to climate disturbances. h Ma y The peak river s o on discharge is registered on e s tM in October, the end of t h w De Sou t pr e the rainy season, and a y - Oc ssi o severe flood damage M n a nd Oct Ty p may arise with high tide h oo l ga n in this period. The en fB Trough Oct mean temperature yo ranges from 26oC to Ba South and Apr rom 31oC. Its maximum Mar n f o ne so temperature is in April er l y W ay cl o M M on Cy 10 00o s t n and its minimum is in ea - Ja ind t h 10o00 December (Figure r v No No J1.1-3). The evaporation (Class-A n Dep 0 100 200 km. Pan) in the basin is oo re s n s N o si o normally at its highest o v an n s tM dD Scale in April and lowest in t h we ct ec October with an u So ay - O average annual total M value of about 1,700 mm (Figure J1.1-4). 100o00 105o00 Source: Data from TMD Figure J1.1-1 Monsoons and Tropical Cyclones in Thailand J-1 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix J: Meteorology and Hydrology 300 235.32 Weighted Average Rainfall (mm) 250 May-Oct 984.24 187.58 Nov-Apr 144.39 200 155.66 144.92 Annual 1,128.64 150 133.82 126.95 100 65.13 50 27.46 28.23 5.66 5.93 11.98 0 APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR Remark: Average from 1977 to 2006 (30 years) by weighting 51 rainfall stations data Source: Data from TMD Figure J1.1-2 Average Rainfall over the Chao Phraya River Basin 32 31 Chiang Mai Nakhon Sawan Bangkok Metropolis 30 29 Mean Temperature ( C) o 28 27 26 25 Annual Mean Temperature (oC) 24 Chiang Mai 25.7 23 22 Nakhon Sawan 28.2 21 Bangkok Metropolis 28.4 20 APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR Remark: Average from 1976 to 2005 (30 years) Source: Data from TMD Figure J1.1-3 Mean Monthly Temperature in the Chao Phraya River Basin 250 Chiang Mai Nakhon Sawan Bangkok Metropolis 200 Mean Pan Evaporation (mm) 150 100 Annual Mean Pan Evaporation (mm) Chiang Mai 1,618 50 Nakhon Sawan 1,962 Bangkok Metropolis 1,760 0 APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR Remark: Average from 1976 to 2005 (30 years) Source: Data from TMD Figure J1.1-4 Mean Monthly Pan Evaporation in the Chao Phraya River Basin J-2 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix J: Meteorology and Hydrology J1.2 River Morphology The Chao Phraya River Basin is as large as one-third (158,592 km2) of the whole country (514,000 km2). The basin is divided into the upper basin of northern highland and the lower basin of the delta area. The Chao Phraya River consists of 8 major tributaries namely, Ping (34,537 km2), Wang (10,793 km2), Yom (24,047 km2), Nan (34,682 km2), Main Chao Phraya (20,523 km2), Sakae Krang (4,907 km2), Pasak (15,626 km2) and Tha Chin (13,477 km2). The Wang joins the Ping and the Yom joins the Nan. Then the Nan joins the Ping from the Chao Phraya River in Nakhon Sawan province. The Chao Phraya River flows down to the lower basin where the Sakae Krang joins and the Tha Chin diverts from the main river before flowing into the Chao Phraya Dam (Barrage) in Chai Nat province. The Pasak joins the Chao Phraya River in the delta area in Phra Nakhon Si Ayutthaya province. The rivers flow southward through a large alluvial plain and reach the sea in the Gulf of Thailand. Topographically, the Lower Chao Phraya River Basin area is flat at an average elevation of +1.00 to +2.00 m.MSL (meter above mean sea level). With certain spots, their elevation is lowered down to sea level due to land subsidence. There are a number of canals crisscrossing the whole lower basin. Bangkok area straddles the Chao Phraya River, 33 km north of the Gulf of Thailand. Due to the flatness of the area and close proxy to the seashore, the area annually faces the problems of floods from the water from the north and inundates due to the high tide from the sea. J2 BASIC ANALYSIS J2.1 Precipitation Data Availability Rainfall in the study area was observed by many agencies. In addition to those of the Meteorological Department (TMD) and the Royal Irrigation Department (RID), some rainfall stations were operated by other agencies such as the Bangkok Metropolitan Administration (BMA), the Department of Water Resources (DWR), and the Electricity Generating Authority of Thailand (EGAT). However, due to a short time available, the daily rainfall data at the selected stations were collected from the agencies concerned. The selected rainfall stations are the representative of the rainfall points in the Chao Phraya River Basin. Table J2.1-1 and Figure J2.1-1 show the 51 selected rainfall stations, their locations, and period of record. All stations are daily recorded by TMD but the data before 1952 are unreliable and missing according to the officials of TMD. The Double Mass Curve Method was applied to check the consistency of the data and most of them are found consistent. The Isohyet map of average annual rainfall (from 1977 to 2006, 30 years) is depicted in Figure J2.1-2. Basin Rainfall The Chao Phraya River Basin has been divided into sub-basins based on main tributaries and major dam locations. The Bhumibol Dam on the Ping River, the Sirikit Dam on the Nan River, the Khwae Noi Dam on the Khwae Noi River and the Pasak Chonlasit Dam on the Pasak River were taken into account. The average basin rainfall was calculated by weighting factors of 51 rainfall stations from 1977 to 2006 (30 years) according to the Thiessen Polygon method. Considering the rainfall pattern in 1995 (Figure J2.1-3), a heavy rainfall was in the Nan River Basin (both upper and lower Sirikit dam) resulting in spillway operation at the dam and flooding in the lower basin. Moreover, heavy rainfall was also in the Yom and the Pasak River Basins where there was no large storage dam to alleviate flooding condition downstream. J-3 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix J: Meteorology and Hydrology Table J2.1-1 The Selected Rainfall Stations in the Chao Phraya River Basin Location Station Mean Annual No. Station Name Period Province Latitude Longitude Code Rainfall (mm) o o 1 A. Wat Sing Chai Nat 15 15'24" 100 02'53" 04062 1921 - 2006 1,041.28 o o 2 A. Muang Chiang Mai 18 50'23" 98 58'32" 07013 1914 - 2006 826.20 o o 3 A. Chiang Dao Chiang Mai 19 21'53" 98 57'60" 07132 1921 - 2006 1,254.69 o o 4 A. Omkoi Chiang Mai 17 47'45" 98 21'36" 07162 1952 - 2006 909.86 o o 5 A. Chom Thong Chiang Mai 18 24'57" 98 40'47" 07182 1922 - 2006 907.82 o o 6 A. Muang Kamphaeng Phet 16 28'56" 99 31'26" 12012 1921 - 2006 1,001.98 o o 7 A. Khanu Woralakburi (Ct.5A) Kamphaeng Phet 15 54'10" 99 28'45" 12081 1970 - 2006 1,208.05 o o 8 A. Muang Lampang 18 17'23" 99 30'27" 16013 1920 - 2006 1,037.65 o o 9 A. Chae Hom Lampang 18 42'07" 99 34'13" 16022 1921 - 2006 1,137.09 o o 10 A. Thoen Lampang 17 36'39" 99 13'08" 16072 1921 - 2006 1,037.08 o o 11 A. Muang Lamphun 18 34'38" 99 00'34" 17012 1920 - 2006 959.66 o o 12 A. Muang Lop Buri 14 47'45" 100 39'22" 19013 1920 - 2006 1,201.52 o o 13 A. Chai Badan Lop Buri 15 12'12" 101 08'10" 19052 1921 - 2006 1,284.44 o o 14 A. Muang Nakhon Pathom 13 49'02" 100 04'16" 23012 1920 - 2006 1,141.35 o o 15 A. Muang Nakhon Sawan 15 42'11" 100 08'28" 26013 1921 - 2006 1,143.04 o o 16 A. Phaisali Nakhon Sawan 15 35'43" 100 39'40" 26122 1967 - 2006 1,060.14 o o 17 A. Muang Nan 18 46'35" 100 46'26" 28013 1920 - 2006 1,200.50 o o 18 A. Tha Wang Pha Nan 19 07'04" 100 48'47" 28073 1968 - 2006 1,408.63 o o 19 A. Sai Noi Nonthaburi 13 58'31" 100 19'05" 31132 1977 - 2006 989.88 o o 20 A. Muang Pathum Thani 14 01'05" 100 32'13" 32012 1920 - 2006 1,182.40 o o 21 A. Nong Sua Pathum Thani 14 07'60" 100 49'41" 32052 1921 - 2006 1,295.00 o o 22 A. Lam Luk Ka Pathum Thani 13 55'50" 100 45'11" 32062 1921 - 2006 1,312.12 o o 23 A. Muang Phetchabun 16 25'00" 101 09'36" 36013 1952 - 2006 1,120.51 o o 24 A. Lom Sak Phetchabun 16 46'42" 101 14'46" 36023 1952 - 2006 1,091.62 o o 25 A. Wichian Buri Phetchabun 15 39'20" 101 06'36" 36043 1951 - 2006 1,185.38 o o 26 A. Taphan Hin Phichit 16 12'44" 100 25'34" 38042 1958 - 2006 1,184.64 o o 27 A. Sam Ngam Phichit 16 30'25" 100 12'32" 38052 1958 - 2006 1,143.47 o o 28 A. Muang Phitsanulok 16 49'24" 100 15'43" 39013 1920 - 2006 1,349.79 o o 29 A. Nakhon Thai Phitsanulok 17 05'56" 100 50'31" 39042 1952 - 2006 1,266.99 o o 30 A. Muang Phrae 18 08'44" 100 08'42" 40013 1920 - 2006 1,138.65 o o 31 Bangkok Metropolis Bangkok 13 43'12" 100 33'43" 41013 1951 - 2006 1,520.07 o o 32 A. Lat Krabang Bangkok 13 43'20" 100 47'17" 41032 1922 - 2006 1,109.63 o o 33 A. Muang Pra Nakhon Si Ayuttaya 14 21'49" 100 34'34" 42012 1920 - 2006 1,131.93 o o 34 A. Bang Phli Samut Prakan 13 36'17" 100 42'32" 51022 1923 - 2006 1,222.59 o o 35 A. Muang Samut Sakhon 13 32'45" 100 16'37" 52012 1921 - 2006 1,294.05 o o 36 A. Muang Saraburi 14 31'35" 100 54'50" 54012 1921 - 2006 1,394.70 o o 37 A. Nong Khae Saraburi 14 20'12" 100 52'08" 54052 1958 - 2003 1,242.77 o o 38 A. Muak Lek Saraburi 14 39'21" 100 12'07" 54192 1976 - 2006 1,224.45 o o 39 A. Muang Sing Buri 14 53'12" 100 24'29" 56012 1920 - 2002 1,084.75 o o 40 A. Muang Sukhothai 17 00'21" 99 49'36" 59012 1921 - 2006 1,137.29 o o 41 A. Si Satchanalai Sukhothai 17 30'55" 99 45'52" 59022 1921 - 2006 1,056.92 o o 42 A. Muang Suphan Buri 14 28'10" 100 07'16" 60013 1920 - 2006 1,132.65 o o 43 A. Song Phi Nong Suphan Buri 14 13'17" 100 01'26" 60042 1922 - 2006 959.19 o o 44 A. Sam Chuk Suphan Buri 14 45'15" 100 05'49" 60072 1922 - 2005 1,000.68 o o 45 Krasieo Self-Supporting Settlement Suphan Buri 14 51'00" 99 34'60" 60684 1992 - 2006 1,251.64 o o 46 A. Muang Tak 16 52'50" 99 07'36" 63013 1921 - 2006 1,015.98 o o 47 Ban Samong, A. Sam Ngao Tak 17 19'60" 98 52'60" 63162 1968 - 2006 877.73 o o 48 A. Lan Sak Uthai Thani 15 28'00" 99 34'00" 69132 1977 - 2006 1,063.76 o o 49 A. Muang Uttaradit 17 37'32" 100 05'56" 70013 1920 - 2006 1,449.33 o o 50 A. Fak Tha Uttaradit 17 59'25" 100 52'55" 70072 1951 - 2006 1,079.97 o o 51 A. Pong Phayao 19 08'32" 100 16'41" 73032 1952 - 2006 1,183.29 Source: Data from TMD J-4 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix J: Meteorology and Hydrology Source: Data from TMD Figure J2.1-1 Location of Hydro-meteorological Stations J-5 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix J: Meteorology and Hydrology Source: Panya Consultants Figure J2.1-2 Annual Rainfall Isohyet of the Chao Phraya River Basin J-6 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix J: Meteorology and Hydrology 500 500 500 450 450 450 Upper Ping Yom Upper Nan 400 400 400 350 Total 1,116.30 mm 350 Total 1,393.60 mm 350 Total 1,645.53 mm 300 300 300 250 250 250 200 200 200 150 150 150 100 100 100 50 50 50 - - - APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR 500 500 500 450 Lower Ping 450 450 Wang Lower Nan 400 400 400 350 Total 1,322.53 mm 350 Total 1,146.42 mm 350 Total 1,503.80 mm 300 300 300 250 250 250 200 200 200 150 150 150 100 100 100 50 50 50 - - - APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR 500 500 500 450 Sakaekrang 450 450 Lower Chao Phraya West Upper Pasak 400 400 400 350 Total 1,532.08 mm 350 Total 1,224.57 mm 350 Total 1,446.94 mm 300 300 300 250 250 250 200 200 200 150 150 150 100 100 100 50 50 50 - - - APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR 500 500 500 450 Tha Chin 450 Lower Chao Phraya East 450 Lower Pasak 400 400 400 350 Total 1,343.72 mm 350 Total 1,394.31 mm 350 Total 1,285.99 mm 300 300 300 250 250 250 200 200 200 150 150 150 100 100 100 50 50 50 - - - APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR Source: Panya Consultants Figure J2.1-3 Rainfall Pattern in the Chao Phraya River Sub-basins in 1995 Rainfall Frequency Analysis A statistical analysis was carried out to estimate probable maximum rainfall of each consecutive day (30, 60, 90, 120, 150, and 180 days) of the Chao Phraya River Basin by applying the Gumbel distribution as summarized in Table J2.1-2. Comparing with the basin rainfall in 1995, the return period of basin rainfall in 1995 varies with the consecutive day. However, most of them are at about 30-year return period except at 150 and 180 consecutive days that they are below a 30-year return period. Therefore, it can be said that the basin rainfall in 1995 is at a 30-year return period. The 120-consecutive day is selected to be applied in the rainfall-runoff analysis. Table J2.1-2 Maximum Rainfall over the Chao Phraya River Basin for Consecutive Days Unit: mm Return Period Consecutive Day (year) 30 days 60 days 90 days 120 days 150 days 180 days 2 258.30 438.20 584.00 717.80 871.00 976.54 5 291.00 496.40 660.20 804.90 965.80 1,086.87 10 312.70 535.00 710.70 862.60 1,028.57 1,159.92 25 340.10 583.70 774.40 935.50 1,107.87 1,252.21 30 345.50 593.30 786.90 949.80 1,123.41 1,270.29 50 360.50 619.90 821.70 989.50 1,166.71 1,320.68 100 380.70 655.80 868.60 1,043.20 1,225.11 1,388.64 Year 1995 321.53 608.26 807.31 964.05 1,116.09 1,213.96 Source: Panya Consultants’ calculation J-7 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix J: Meteorology and Hydrology J2.2 Temperature and Evapotranspiration Temperature is related to evapotranspiration. If temperature increases, evapotranspiration will increase. The evapotranspiration affects the process of hydrologic cycle. If evapotranspiration increases, river runoff from the rainfall will decrease. Therefore, the factor of increasing evapotranspiration resulting from increasing temperature is analyzed. The mean meteorological data (mean maximum and minimum temperatures, relative humidity, wind velocity, and sunshine duration) from 1970 to 2000 at 9 stations (Muang districts of Chiang Mai, Lumpang, Phrae, Nan, Tak, Phitsanulok, Suphan Buri, and Wichian Buri district of Phetchabun) in the Chao Phraya River Basin were collected from TMD to calculate monthly evapotranspiration by Penman-Monteith method. According to the A1FI and B1 scenarios, the temperature would increase by 1.9 oC and 1.2 oC in 2050 respectively (JBIC, 2008). The mean temperature increases resulting in increasing evaprotranspiration by 5 and 3% for A1FI and B1 respectively as summarized in Table J2.2-1. Table J2.2-1 Increasing Factor of Evapotranspiration for A1FI and B1 Unit: mm/day Bang Chiang Lam Phitsa Phet Suphan Station Phrae Nan Tak chabun Buri Average kok Mai pang nulok Avg. 4.45 4.15 3.84 3.99 3.67 4.29 4.15 4.03 4.50 4.12 A1FI 4.66 4.34 4.01 4.18 3.84 4.48 4.35 4.21 4.71 4.31 Factor 1.049 1.046 1.045 1.046 1.046 1.045 1.046 1.045 1.048 1.046 B1 4.58 4.27 3.95 4.11 3.78 4.41 4.27 4.14 4.64 4.24 Factor 1.031 1.029 1.028 1.029 1.029 1.028 1.029 1.028 1.030 1.029 Remark: Average from 1970 to 2000 and A1FI and B1 increased temperature by 1.9 oC and 1.2 oC in 2050 respectively Source: Panya Consultants’ calculation For daily evapotranspiration, it is usually estimated from daily evaporation (recorded Class-A Pan evaporation) by applying factor of 0.7. The daily evaporation data of 9 stations were collected for the rainfall-runoff analysis as summarized in Table J2.2-2. Table J2.2-2 List of Evaporation Stations Location Station Mean Annual No. Station Name Period Evap. ETP. Province Latitude Longitude Code ETP. (mm) (mm) (mm/day) 1 A. Muang Chiang Mai 18o50'23" N 98o58'32" E 327501 1914 - 2006 1,634.67 1,144.27 3.13 2 A. Muang Lampang 18o17'23" N 99o30'27" E 328201 1920 - 2006 1,472.13 1,030.49 2.82 o o 3 A. Muang Nan 18 46'35" N 100 46'26" E 331201 1920 - 2006 1,257.92 880.54 2.41 o o 4 A. Wichian Buri Phetchabun 15 39'20" N 101 06'36" E 379402 1951 - 2006 1,702.72 1,191.90 3.27 o o 5 A. Muang Phitsanulok 16 49'24" N 100 15'43" E 378201 1920 - 2006 1,661.40 1,162.98 3.19 o o 6 A. Muang Phrae 18 08'44" N 100 08'42" E 330201 1920 - 2006 1,630.67 1,141.47 3.13 Bangkok 7 Bangkok 13o43'12" N 100o33'43" E 455201 1951 - 2006 1,740.10 1,218.07 3.34 Metropolis 8 A. Muang Suphan Buri 14o28'10" N 100o07'16" E 425201 1920 - 2006 1,852.48 1,296.73 3.55 o o 9 A. Muang Tak 16 52'50" N 99 07'36" E 376201 1921 - 2006 1,835.14 1,284.60 3.52 Remark: Evap. = Evaporation, ETP. = Evapotranspiration = 0.7 x Evap. Source: Data from TMD J-8 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix J: Meteorology and Hydrology J2.3 Runoff The river flow rates show a seasonal variation with a distinctive imbalance of precipitation between the rainy and dry seasons. The river flow rates start to increase in April and reache its peak in September or October when an intensive precipitation is caused by the tropical cyclonic disturbances. An example of discharge hydrographs in the Chao Phraya River at Nakhon Sawan Station (C.2) and Chai Nat Station (C.13) and in the Pasak River at Kaeng Khoi Station (S.2) is shown in Figure J2.3-1. 5000 Chao Phraya River at Nakhon Sawan Station (C.2) 4500 Chao Phraya River at Chai Nat Station (C.13) Pasak River at Kaeng Khoi Station (S.2) 4000 3500 3000 Discharge (m3/sec) 2500 2000 1500 1000 500 0 1/4/95 1/5/95 31/5/95 30/6/95 30/7/95 29/8/95 28/9/95 28/10/95 27/11/95 27/12/95 26/1/96 25/2/96 26/3/96 Source: Data from RID Figure J2.3-1 Discharge Hydrographs in the Chao Phraya and Pasak Rivers The daily and maximum discharges were collected at 8 stations on the Chao Phraya River and its tributaries as shown in Table J2.3-1. The maximum discharges in the Chao Phraya River at Nakhon Sawan Station (C.2) where four main tributaries (Ping, Wang, Yom, and Nan) joined and in the Pasak River at Saraburi Station before flowing into the Chao Phraya River at Phra Nakhon Si Autthaya were analyzed by Gumbel distribution as shown in Table J2.3-2. Table J2.3-1 List of Stream Gauging Stations Location Station Catchment No. River Station Name Period 2 Province Latitude Longtitude Code Area (km ) o o 1 Chao Phraya Khai Chira Prawat Nakhon Sawan 15 40' 15" 100 06' 45" C.2 110,569 1949-2006 o o 2 Chao Phraya Wat Pho Ngam Chai Nat 15 09' 57" 100 11' 32" C.13 120,693 1947-2006 o o 3 Khwae Noi Ban Nong Bon Phitsanulok 17 13' 14" 100 21' 10" N.40 4,340 1977-2006 o o 4 Pasak Kaeng Khoi Saraburi 14 35' 32" 101 00' 23" S.2 14,522 1914-2006 o o 5 Pasak Ban Chong Nua (Ban Rerai) Saraburi 14 37' 33" 101 01' 00" S.9 14,374 1973-2006 o o 6 Wang Ban Wang Man Tak 17 12' 22" 99 06' 08" W.4A 10,507 1971-2006 o o 7 Yom Ban Kaeng Luang Sukhothai 17 26' 03" 99 47' 32" Y.6 12,658 1952-2006 o o 8 Yom Sam Ngam Phichit 16 30' 50" 100 12' 40" Y.17 21,415 1967-1980,1990-2006 Source: Data from RID J-9 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix J: Meteorology and Hydrology Table J2.3-2 Maximum Discharge in the Chao Phraya and Pasak Rivers Unit: m3/sec Station Station Catchment Return Period (year) River Province Period 1995 Name Code Area (km2) 10 30 100 Chao Khai Chira Nakhon C.2 110,569 1972-2006 4,800 3,784 4,831 5,953 Phraya Prawat Sawan Kaeng Pasak S.2 Saraburi 14,522 1998-2006 1,000 1,173 1,574 2,005 Khoi Source: Panya Consultants’ calculation J2.4 Water Level and Sea Level The tide in the Gulf of Thailand is the mixed tide with a maximum tidal range of about 3.5 m. During the dry season, the seawater reaches about 160 km upstream from the river mouth. On the other hand, the tidal wave is damped by the river flood flow during the rainy season. For instance, at the peak of the 1995 flood, tidal effect was barely observed even in Pak Kret district, Nonthaburi province, about 70 km upstream from the river mouth. Seasonal variation of the sea level is found in the Gulf of Thailand. The sea level is high from October to January and low from June to August. Such sea level variation is caused by the combination of astronomical and meteorological effects. Unfortunately, the peak river flow mostly coincides with the swelling of the sea in October. The river water level is raised higher by the backwater from the swelled sea. The daily water level data in the Chao Phraya River were collected at 10 stations as shown in Table J2.4-1. The hourly sea level data were collected at Phra Chunlachomklao Fort (Fort Chula) at the river mouth of the Chao Phraya River and at the river mouth of the Tha Chin River from 1985 to 2005. The maximum sea levels are +2.56 m.MSL on 26/05/1998 at 19:00 (+2.51 m.MSL on 28/10/1995 9:00, Figure J2.4-1) and +2.41 m.MSL on 15/12/1995 at 11:00 respectively. Table J2.4-1 List of Water Level Gauging Stations Location Drainage Station No. River Station Name Period Code Area Changwat Latitude Longtitude (km2) o o 1 Chao Phraya Ban Bang Phutsa Sing Buri 14 53'44" 100 24'14" C.3 Flood Plain 1950-2006 o o 2 Chao Phraya Memorial Bridge Bangkok 13 44'15" 100 29'55" C.4 Flood Plain 1977-2006 o o 3 Chao Phraya Ban Bang Kaeo Ang Thong 14 35'05" 100 27'12" C.7A Flood Plain 1971-2006 o o 4 Chao Phraya R.I.D. Bangkok Bangkok 13 47'14" 100 30'56" C.12 Flood Plain 1963-2006 o o 5 Chao Phraya R.I.D. Pak Kret Nonthaburi 13 53'47" 100 29'39" C.22 Flood Plain 1964-2006 o o 6 Chao Phraya Ban Khaek Phra Nakhon Si Ayutthaya 14 11'33" 100 30'23" C.29 Flood Plain 1987-1996 o o 7 Chao Phraya Ban Prok Pathum Thani 14 01'12" 100 32'22" C.31 Flood Plain 1984-1996 o o 8 Chao Phraya Ban Pom Phra Nakhon Si Ayutthaya 14 20'19" 100 32'56" C.34 Flood Plain 1992-1996 o o 9 Chao Phraya Ban Pom Phra Nakhon Si Ayutthaya 14 22'08" 100 31'53" C.35 Flood Plain 1992-2006 Panchama Thirat Uthit o o 10 Pasak Phra Nakhon Si Ayutthaya 14 21'32" 100 35'02" S.5 Flood Plain 1950-2006 Hospital Source: Data from RID J-10 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix J: Meteorology and Hydrology 3.00 Chao Phraya River Mouth (Fort Chula) Tha Chin River Mouth 2.50 2.00 1.50 Water Level (m.MSL) 1.00 0.50 0.00 -0.50 -1.00 27/10/95 27/10/95 28/10/95 28/10/95 29/10/95 29/10/95 30/10/95 Source: Data from HDD and HD Figure J2.4-1 Sea Level at the River Mouths of Chao Phraya and Tha Chin However, the water level along the Chao Phraya River from the river mouth is not as high as the sea level at the river mouth as shown in Figure J2.4-2. The travel time of flood hydrograph from Nakhon Sawan to Bangkok is about 20-30 days for a distance of about 275 km. Special attention should be paid in observed tidal and water level data in the delta area because most of the gauge seems to have subsided to some extent in the progress of land subsidence. However, the operating agencies have been adjusted the gauge datum in some years based on the revised reference bench mark datum but details are not available. Moreover, the observed land subsidence has not been recorded at the gauge and it is hardly estimated. However, the scale of accumulated land subsidence is only in cm, hence, the collected data in this study are not adjusted. J-11 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix J: Meteorology and Hydrology C.2 C.13 C.3 C.7A C.34 C.22 C.4 30 28 26 24 22 Water Level (m.MSL) 20 18 16 14 12 10 8 6 4 2 0 1/9/95 11/9/95 21/9/95 1/10/95 11/10/95 21/10/95 31/10/95 10/11/95 20/11/95 30/11/95 C2 C13 C3 C7A C22 C4 30 28 26 24 22 Water Level (m.MSL) 20 18 16 14 12 10 8 6 4 2 0 1/9/02 11/9/02 21/9/02 1/10/02 11/10/02 21/10/02 31/10/02 10/11/02 20/11/02 30/11/02 C2 C13 C3 C7A C4 30 28 26 24 22 Water Level (m.MSL) 20 18 16 14 12 10 8 6 4 2 0 1/9/06 11/9/06 21/9/06 1/10/06 11/10/06 21/10/06 31/10/06 10/11/06 20/11/06 30/11/06 Remark: Nakhon Sawan (C.2), Chai Nat (C.13), Sing Buri (C.3), Ang Thong (C.7A), Ayutthaya (C.34), Nonthaburi (C.22), and Bangkok (C.4) Source: RID Figure J2.4-2 Water Level along the Chao Phraya River in 1995, 2002, and 2006 J-12 APPENDIX K MATHEMATICAL MODEL DEVELOPMENT AND SIMULATION Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation APPENDIX K MATHEMATICAL MODEL DEVELOPMENT AND SIMULATION K1 MODEL DEVELOPMENT K1.1 Model Setup To set up a mathematical model for simulating the flood inundation mechanism caused by rainfall and affected by sea level rise in the delta area of the Lower Chao Phraya River Basin where the BMR is situated, it is necessary to consider the entire Chao Phraya River Basin of about 158,600 km2 because most of the flood volume comes from the upper basin. The two large storage dams, Bhumibol and Sirikit, in the upper basin can regulate the flood volume upstream and reduce the inundation area downstream of the dams significantly. In the near future, Khwae Noi Dam on the Khwae Noi River, a tributary of the Nan River in the upper basin, will be completed and operated. This dam has to be included in the model for the future case study. In the Lower Chao Phraya River Basin, Pasak Chonlasit Dam on the Pasak River alleviates the flood damage downstream including the area of BMR. Other small to medium storage dams are ignored because of lesser role in flood damage alleviation. In addition, principal existing or planned river/canal network, barrages, dikes, and pumping stations are included. For the shoreline of this project, the model is setup covering about 80 km in the areas of Bangkok, Samut Prakarn, and Samut Sakhon and in the Gulf of Thailand about 5 km from the shore. All mentioned components are included in the model setup. The developed model is applied to clarify the flood inundation mechanism and to determine basic hydrological parameters and effectiveness of the proposed countermeasures. The MIKE FLOOD (including MIKE 11 GIS) software package developed by the Danish Hydraulic Institute (DHI) was selected. The MIKE FLOOD is a unique integrated flood modeling package for rivers and flood plains (MIKE 11) and for flows, waves, estuaries, coastal areas and seas (MIKE 21). It dynamically couples well proven one-dimension (MIKE 11) and two- dimension (MIKE 21) modeling techniques into one single powerful tool. The MIKE 11 GIS is a powerful extension for ArcView providing features for catchment/river delineation, cross-section, and digital elevation model (DEM) data, flood visualization/animation as 2D maps, and result presentation/analysis using the Temporal Analyst. In MIKE 11, runoffs generated in sub-basins from rainfall inputs are calculated by the rainfall- runoff model (NAM module) and given to flood routing of the Hydrodynamic model (HD module). The NAM simulates the hydrological process in sub-basin as a lumped model. It operates by continuously accounting for the moisture content in the four different and mutually interrelated storage tanks. The HD in MIKE 11 is a one-dimensional dynamic flow model but can be applied to looped networks over the flood plain area. Besides the HD and NAM modules, the Structure Operation module (SO) for control structures, weirs, pumping stations, etc., and other useful modules are available. In MIKE 21, the HD simulates the water level variations and flows along a rectangular mesh grids or bathymetry, covering an area of interest. The MIKE 11 results for each time step calculation are boundary conditions of MIKE 21 apart from its provided boundary such as tide, discharge hydrograph, etc. The developed model generates runoffs from sub-basins and routes through the river/canal network and flood plain which includes principal reservoirs, control structures, and pumping stations as shown in Figure K1.1-1. It was calibrated and verified based on the observed discharges and water levels at selected stations for the targeted flood of 1995 and 2002. They were severe floods recorded in the recent past in the Chao Phraya River Basin and had complete observed data set of rainfall, water level, and discharge at the selected stations. There was also a severe flood in 2006, but unfortunately the observed discharge data in Nakhon Sawan (C.2) is missing during the flooding period. K-1 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation Legend River Wang River Canal (Khlong, K.) Yom River Bhumibol Dam Reservoir Sirikit Dam Barrage Pumping Station Khwae Noi Dam Bathymetry Ping (under construction) Suvarnabhumi International Rive r River Nan Airport Nakhon Sawan Chain at-Pa R ive r sak in Tha Ch Chao Phraya Dam iver (Barrage) ak R Pasak Chonlasit Dam er Pa s Riv yok n Na K.Ra kho Ayutthaya phi P Na Rama VI Barrage hat K.Mae Nam Nok P18 Tok Chao Phraya River hat Y aek Sak er K.Raphi P t Prayun Riv K.13 K.14 K.Rangsi P17 ong Pak K.1 P16 ng Ba K.16 P19 a Sai Lang K.14 K.15 K.13 K.Hok W P15 K.2 P24 K.21 K.Omm Bangkok Noi Tha Chin River i P14 K.Bang Ya K.17 K.14 K.15 K.16 K.San Saeb K.8 at P23 K.Maha Saw Saeb K.Nakhon Nuea Bang Pakong River K.San K.Phra-Ong Chao ng Khet P13 P25 roen K.Bangkok Yai Bangkok Chaiyanuchit K.Phasi Cha K.Lat Krabang K.Prawat Buri Rom P22 P12 Short Cut K.Khun Rat Phinit Chai P26 .Sanam Chai K.Suvarnabhumi (Barrage) P20 P11 K.Charoen Rad K K.Samrong K.Bang Pla P27 P28 P21 K.Dan ith K.Phithaya Longkon K.Sappasam K.Chai Talae P10 The Gulf of Thailand P1 P2 P3 P4 P5 P6 P7 P8 P9 Source: Panya Consultants Figure K1.1-1 Schematic Diagram of Model Setup K1.2 Model Inputs River/Canal Network and Cross-sections The river and canal cross-sections surveyed by the Royal Irrigation Department (RID) in different years from 1983 to 2006 were used in the model. Intervals of the cross-sections range from 1 to 5 km. The Ping River cross-sections from Bhumibol Dam to the Chao Phraya River in Nakhon Sawan province and in the Nan River from Sirikit Dam and in the Kwae Noi River from Kwae Noi Dam are used. The Chao Phraya River cross-sections from Nakhon Sawan to the river mouth at the Gulf of Thailand are used with the river distance of about 375 km. The Tha Chin River cross- sections from Chai Nat province to the river mouth are used with the river distance of about 319 km. Others are major drainage canals that cross-sections are available but some cross-sections were estimated by visualization at sites. Figure K1.2-1 depicts the river/canal network including cross-section, control structure, and pumping station locations. The flood plains outside the bathymetry area were treated as extended river cross-sections and ponds were treated as area-elevation curves obtained from the topographic map scale of 1:50,000 established by the Royal Thai Survey Department (RTSD). K-2 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation 1740000 Nakhon Sawan Chao Phraya River 1980000 Sirikit C.2 Gauging Station er 1720000 1960000 Nan Riv Lower Chao Phraya Basin 1940000 1700000 Cha i Na iver 1920000 t-Pa Khwae Noi sa k Wang R Bhumibol 1680000 Can al Cha 1900000 Chao o Phr Phraya Noi 1660000 aya 1880000 wae Barrage Pasak Kh er R Chonlasit iver 1860000 Riv 1640000 Tha Chin 1840000 1620000 Rama VI r ive Nan River 1820000 Barrage R sak Rive Pa Pin r 1600000 g 1800000 Yom River Riv er 1780000 Upper Chao Phraya Basin 1580000 River 1760000 Chao Phraya 1560000 1740000 1720000 Nakhon Sawan 1540000 C.2 Gauging Station 1700000 450000 500000 550000 600000 650000 1520000 Symbol Reservoir River/Canal Line Control Structure 1500000 and Cross-section Main Tributary Location Pumping Station 1480000 600000 650000 700000 Source: Panya Consultants Figure K1.2-1 River/Canal Network of Model Setup Water Level and Discharge The historical water level and discharge records are required for both NAM and HD Model calibration and verification and also for boundary condition inputs. Most of the data were monitored by RID. The daily water level data at 10 selected gauging stations on the Chao Phraya and Pasak Rivers were collected from RID. The daily discharge data at 8 selected gauging stations on the rivers were also collected from RID. The daily released discharge, water level, and calculated inflow of reservoirs at Bhumibol and Sirikit Dams operated by the Electricity Generating Authority of Thailand (EGAT) and Pasak Chonlasit Dam operated by RID were collected. In addition, hourly sea level data at the Phra Chunlachomklao Fort (Fort Chula) and the Tha Chin River mouth were collected from the Hydrographic Department and the Harbor Department respectively. Hydraulic Structures Flood protection dikes have been constructed mainly on the natural levees along both banks of the Chao Phraya, Tha Chin, and lower parts of the Pasak Rivers. On the other hand, in actual floods, the banks of canals for irrigation or embankments of roads on the natural levee and the hinterland along the river have taken the role of flood protection dikes form the river. The BMA has been constructing polder dike systems together with improvement of drainage systems including pump facilities and diversion tunnels to protect the city core and to drain local flood water along the roads during high intensity rainfall. The RID has been improving and constructing dikes, pumping stations, and diversion canals to protect the eastern and western areas of Bangkok from flooding. These existing and planned flood protection scheme data were obtained from the BMA and the RID. The reservoir-capacity curves, operation rules (Rule Curves), and characteristic of spillways, outlets, and pumping stations were obtained from the agencies concerned (EGAT, RID, and BMA). Table K1.2-1 shows the operation rule and area-capacity tables of the major reservoirs. K-3 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation Table K1.2-1 Operation Rule and Area-Capacity Table of the Major Reservoirs Unit: m.MSL Reservoir Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Bhumibol Reservoir Upper Rule 254.00 253.50 253.00 253.50 256.00 258.00 260.00 260.00 260.00 260.00 259.00 256.50 Lower Rule 242.10 240.20 238.10 237.00 238.40 242.20 244.20 244.50 244.60 244.20 244.00 243.30 Sirikit Reservoir Upper Rule 152.00 150.00 149.50 153.00 157.00 161.50 162.00 162.00 162.00 161.50 159.00 155.50 Lower Rule 146.00 144.00 142.00 141.00 146.00 151.00 152.00 151.70 151.30 151.00 150.00 148.00 Khwae Noi Reservoir Upper Rule 114.00 114.30 120.00 128.90 130.00 130.00 130.00 130.00 130.00 130.00 128.70 121.60 Lower Rule 107.00 106.00 109.10 114.50 123.30 127.90 129.10 128.90 128.80 127.70 125.40 116.90 Pasak Chonlasit Reservoir Upper Rule 41.00 41.00 41.00 41.00 42.00 42.00 42.00 42.00 42.00 42.00 42.00 41.00 Lower Rule 32.00 33.00 36.00 36.00 36.00 37.00 40.00 41.00 41.00 33.00 33.00 33.00 Bhumibol Reservoir (1964) Sirikit Reservoir (1974) Khwae Noi Reservoir (2009) Pasak Chonlasit Reservoir (1998) Elevation Area Capacity Remark Elevation Area Capacity Remark Elevation Area Capacity Remark Elevation Area Capacity Remark (m.MSL) (km2) (MCM) (m.MSL) (km2) (MCM) (m.MSL) (km2) (MCM) (m.MSL) (km2) (MCM) +140.00 - - RBL +65.00 - - RBL +65.00 - - +30.00 - - RBL +150.00 10 50 +70.00 2 7 +70.00 0.30 0.76 +32.00 9 3 DSL +170.00 40 534 +80.00 6 42 +80.00 1.65 10.50 +32.50 12 21 +190.00 68 1,600 +90.00 17 125 +90.00 4.83 42.86 DSL +34.00 27 48 +210.00 100 3,334 +100.00 44 417 +100.00 10.88 121.37 +36.00 55 133 +213.00 106 3,800 DSL +110.00 75 1,050 +110.00 21.32 282.36 +38.00 87 287 +230.00 150 5,800 +120.00 104 2,000 +115.00 26.65 402.28 +40.00 120 509 +250.00 244 9,400 +128.00 126 2,850 DSL +120.00 32.08 549.10 +42.00 149 785 FSL +260.00 316 13,462 FSL +130.00 132 3,250 +125.00 38.36 725.21 +43.00 164 960 MWL +261.00 320 15,000 TDL +140.00 172 4,700 +130.00 47.30 939.36 FSL +43.80 176 1,000 Remark: RBL = Reservoir Bottom Level +150.00 208 6,650 +132.50 53.15 1,066.38 MWL +44.00 192 1,124 DSL = Dead Storage Level +160.00 250 8,800 +133.00 54.32 1,091.78 +46.20 252 1,567 TDL FSL = Full Supply Level +162.00 260 9,510 FSL +135.00 59.00 1,193.38 TDL MWL = Maximum Water Level +166.00 274 10,508 MWL Source: Bhumibol and Sirikit Dams from EGAT TDL = Top of Dam Level +169.00 285 11,500 TDL Khwae Noi and Pasak Chonlasit Dams from RID Bhumibol Dam has been operated since 1964, mainly for irrigation and hydropower purposes. It is a concrete arch dam of 154 m height and 486 m crest length. The total installed capacity (8 units) is 779.2 MW with an annual generated energy of 1,227.88 GWh. The total maximum released capacity is 484 m3/sec. The spillway consists of two tunnels (horseshoes shape), 11.30 m in diameter each with the total capacity of 6,000 m3/sec. The spillway inlet is installed with four radial gates of 11.0 x 17.4 m each and the crest of inlet elevation of +242.90 m.MSL. Sirikit Dam has been operated since 1974, mainly for irrigation and hydropower purposes. It is an earthfill dam with clay core, 113.6 m height and 800 m crest length. The total installed capacity (4 units) is 500 MW with an annual generated energy of 898.57 GWh. The total maximum released capacity is 732 m3/sec. The spillway consists of two tunnels (horseshoes shape), 11.00 m in diameter each with the total capacity of 3,250 m3/sec. The spillway inlet is installed with two radial gates of 11.85 x 15.00 m each and the crest of inlet elevation of +150.50 m.MSL. Pasak Chonlasit Dam has been operated since 1998, mainly for irrigation purpose. It is an earthfill dam with clay core, 36.50 m height and 4,860 m crest length. The river outlet is a conduit of 3.00 m in diameter and capacity of 80 m3/sec. The spillway is installed with 7 radial gates of 12.50 m width each with the total capacity of 3,900 m3/sec and the spillway crest elevation of +34.50 m.MSL. There is an auxiliary spillway of 3.00 m in diameter with capacity of 65 m3/sec and the crest of inlet elevation of +29.00 m.MSL. Khwae Noi Dam is under construction and has been planned to be operated in 2011, mainly for irrigation purpose. It is composed of a concrete faced rockfill dam, 75 m height and 681 m crest K-4 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation length, and a couple dam which is rockfill dam with clay core, 80 m height and 1,260 m crest length. In addition, there is a closure dam which is an earthfill dam, 16 m height and 640 m crest length. The river outlet is a conduit of 2.70 m in diameter with capacity of 108 m3/sec. The spillway is installed with 6 radial gates of 13.50 x 11.50 m each with the total capacity of 7,046 m3/sec and the spillway crest elevation of +110.00 m.MSL. Chao Phraya Dam (Barrage) has been operated since 1957, mainly for irrigation purpose. It is installed with 16 radial gates of 7.50 x 12.50 m each with the total maximum capacity of 3,300 m3/sec and the sill elevation of +9.00 m.MSL. However, the maximum released discharge is controlled at 2,500 m3/sec. Rama VI Barrage on the Pasak River has been operated since 1924, mainly for irrigation purpose. It is installed with 6 slide gates of 12.50 m width each with the total maximum capacity of about 900 m3/sec and the sill elevation of +0.10 m.MSL. Chao Phraya Short Cut Barrage (Khlong Lat Po Improvement Project) has been operated since 2006 to accelerate discharge into the Gulf of Thailand. The canal distance is only 600 m from the inlet to outlet while that along the Chao Phraya River is 18 km. Hence, the travel time of flood flow is reduced significantly. However, it is affected by tide, so the barrage has to close during the high tide period. The barrage is installed with 4 slide gates of 14.00 m width each with the total maximum capacity of about 500 m3/sec and the sill elevation of -7.00 m.MSL. Regulators There are many regulators in the major rivers/canals to regulate the flood flow in the inundation area. The Phonlathep head regulator on the Tha Chin River and the Manorom head regulator on the Chai Nat-Pasak canal regulate the diverted water from the Chao Phraya River upstream of the Chao Phraya Dam. Others are on drainage canals to protect flood flowing into the protected area and at the pumping stations. These regulators data were collected from the BMA and RID. The operation rules of pumping stations in the eastern and western areas of Bangkok depend on the water level in the drainage canals. BMA and RID operate pumping to keep the water level of canals at the targeted levels. However, pumps have to be operated synchronously, hence, the telemetering together with flood forecasting and warning systems have been developed by the BMA and RID. The targeted control water levels are summarized in Table K1.2-2. Table K1.2-2 Target Water Level Control in the Major Drainage Canals Unit: m.MSL No. Canal Max. Water Level Min. Water Level 1 Raphi Phat Yak Tok +1.30 +0.30 2 Rangsit Prayun Sak +1.20 +0.20 3 Hok Wa Sai Lang +1.15 +0.15 4 San Saeb +1.10 +0.10 5 Prawat Buri Rom +0.65 +0.00 6 Samrong +0.40 -0.30 7 Chai Talae +0.35 -0.30 8 Maha Sawat +1.10 +0.10 9 Phasi Charoen +0.65 +0.00 10 Sanam Chai +0.40 -0.30 11 Khun Rat Phinit Chai +0.35 -0.30 Source: RID’s Office Region 11, BMA, and Panya Consultants’ adjustment K-5 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation The RID and the BMA have improved flood protection systems on the left bank of the Chao Phraya River or the eastern area of Bangkok. However, the eastern area outside the protection dike (King’s dike) is a natural floodway of the delta area for a long time. Because of rapid land development into the east, the floodway has been obstructed resulting in severe flooding in this area. In addition, the Suvarnabhumi International Airport was constructed on this floodway resulting in more flooding problems in the area around the airport especially in the north of airport. To solve the flooding problem in the area around Suvarnabhumi International Airport, the RID has constructed the new Khlong Suvarnabhumi from Khlong Samrong to the new pumping station with a capacity of 100 m3/sec to drain the flood water out directly into the Gulf of Thailand (RID, 2004). This project will be completed by 2009. Extension of flood protection dikes, including three new pumping stations, on the eastern area of Bangkok from existing King’s dike to cover the eastern area of Bangkok has been carried out by the BMA and the RID and will be completed by 2009. BMA has constructed the flood protection dikes along the Chao Phraya River, Khlong Maha Sawat and Khlong Bangkok Noi which have the crest elevations range from +2.50 to +3.00 m.MSL (downstream to upstream) and will be completed by 2010. For sustainable planning of the flood protection system in the Lower Chao Phraya River Basin, the RID studied the Improvement of River and Drainage System in the east of Lower Chao Phraya Basin to divert water into Bang Pakong River and the Gulf of Thailand (RID, 2006). The study proposed to improve the existing canals and pumping stations and to construct new ones to divert flood water from the north via Khlong Chai Nat-Pasak, Raphi Phat, Khlong 13, 14 and 17, Khlong Hok Wa Sai Lang, Nakhon Nueang Khet, Prawat Buri Rom, Phra-Ong Chao Chaiyanuchit, and Khlong Dan into the Bang Pakong River and the Gulf of Thailand. The recommended scheme is planned to be completed by 2011 and is summarized in Table K1.2-3. The feasibility design of canals and pumping stations of this project were collected and used in the model simulation for the future case study. In addition, RID has been constructing the flood protection dikes (concrete wall and embankment) along both banks of the Chao Phraya River from the Chao Phraya Barrage to Bangkok which will be completed in 2010. The crest elevation of dikes range from +2.50 to +3.00 m.MSL (downstream to upstream) in the area of Bangkok and from +3.00 to +17.00 m.MSL from Bangkok to the Chao Phraya Dam. In the western area of Bangkok, the BMA has been improving and constructing sub-polder dike systems, including pumping stations, to protect the area in each district (BMA, 2005a) besides the dike along Khlong Maha Sawat and along the Chao Phraya River. There are four major pumping stations at Khlong Maha Sawat, Phasi Charoen, Sanam Chai, and Khun Rat Phinit Chai with capacities of 18, 18, 36, and 30 m3/sec respectively to drain the flood water into the Tha Chin River and the Gulf of Thailand. Figure K1.2-2 to K1.2-4 depicts the schematic diagrams of the model in 1995, 2002, and 2050 respectively. DEM The Digital Elevation Model (DEM) is essential for the flood inundation simulation. In this study, the DEM was prepared from the data obtained from relevant agencies. Ground surface elevations in the eastern area of Bangkok were derived from the topographic maps scale of 1:4,000 surveyed by BMA in 2006 (BMA, 2007g). For other areas, the spot elevations surveyed by the Department of Mineral Resources and the Royal Thai Survey Department in 2002 were used. For the sea bottom elevations, the DEM was derived from eco-sounding surveyed by the BMA in 2006. However, some locations of ground surface elevations have to be adjusted to fit the bank elevations of the surveyed cross-sections. K-6 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation Table K1.2-3 Improvement of Flood Protection System in the Eastern Area of Bangkok 3 3 Existing Capacity (m /sec) New Capacity (m /sec) Pump Completed No. Description Khlong Pump Khlong Pump Code Year 1 Drainage System in the East of Bangkok Pumping Station 1) Tomru 18.00 18.00 P1 2) Bang Plara 42.00 42.00 P2 3) Bang Pla 42.00 42.00 P3 4) Charoen Rad 75.00 75.00 P5 5) Dan 2 24.00 24.00 P6 6) Chonrahan Phichit 120.00 120.00 P7 7) Nang Hong 12.00 21.00 P8 2011 8) Phraya Wisut 12.00 12.00 P9 9) Tep Rangsan 12.00 12.00 P10 10) Pak Takong 12.00 12.00 P11 11) Tha Thu 18.00 24.00 P12 2011 12) Tha Kai 12.00 24.00 P13 2011 13) Banh Kanak 12.00 30.00 P14 2011 14) Khlong 21 12.00 12.00 P15 15) Sombun 15.00 42.00 P16 2011 16) Sourwapa Pongsri 15.00 21.00 P17 2011 17) Bang Prakod 150.00 P18 2011 17) Chula Rongkorn 36.00 36.00 P19 18) Phrakanong 173.00 173.00 P20 19) Samrong 75.00 75.00 P21 Sub-total 737.00 965.00 Khlong 1) Raphi Phat 120.00 400.00 2011 2) Khlong 13 (Raphi Phat Yak Tai) 80.00 200.00 2011 3) Khlong 13 80.00 108.06 2011 4) Khlong 14 30.00 57.40 2011 5) Nakhon Nueang Khet 30.00 58.15 2011 6) Khlong 33-Mae Nam Nok 30.00 200.00 2011 7) Hok Wa Sai Lang 36.00 116.60 2011 8) Prawet Buri Rom 20.00 24.00 2011 9) Dan 76.00 134.27 2011 10) Phra-Ong Chao Chaiyanuchit 75.00 110.64 2011 11) Khlong 17 30.00 71.26 2011 Sub-total 607.00 1,480.38 2 Extension of the East of Bangkok Flood Protection 2.1 Prawat Buri Rom Pumping Station 60.00 P22 2009 2.2 San Saeb Pumping Station 60.00 P23 2009 2.3 Hok Wa Sai Lang Pumping Station 36.00 P24 2009 Sub-total 156.00 3 Suwanabhumi Flood Drainage Improvement 3.1 Khlong Suwanabhumi 100.00 2009 3.2 Pumping Station 100.00 P4 2009 Sub-total 100.00 100.00 Total (exclude 2) 607.00 737.00 1,580.38 1,065.00 Total 607.00 737.00 1,580.38 1,221.00 Source: The Feasibility Study on Drainage System in the Area around Suvarnabhumi Airport (RID, 2004) and RID’s Office Region 11 K-7 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation Legend River Wang River Yom River Canal (Khlong, K.) Bhumibol Dam Reservoir Sirikit Dam Barrage Upper Khwae Noi River Pumping Station Bathymetry Ping er Rive r k Riv Dike r Rive asa N an er P Upp Nakhon Sawan Chain Schematic Diagram in 1995 at-Pa in R iv er sak Tha Ch Chao Phraya Dam iver (Barrage) ak R r Pas ive kR ayo K.Ra nN phi kho Ayutthaya Rama VI Barrage Phat Na k K.Mae Nam Nok To Chao Phraya River hat Yaek ak r K.Raphi P Prayun S ive K.13 K.14 K.Rangsit P17 gR kon Pa K.1 P16 ng Ba K.16 P19 Sai Lang K.14 K.15 K.Hok Wa K.13 P15 K.2 K.21 K.Omm Bangkok Noi Tha Chin River i P14 K.Bang Ya K.17 K.14 K.15 K.16 K.San Saeb K.8 wat K.Maha Sa K.Nakhon Nuea Bang Pakong River Saeb ng Kh et P13 K.San K.Phra-Ong Chao Bangkok Chaiyanuchit aroen K.Bangkok Yai K.Lat Krabang K.Phasi Ch K.Prawat Buri Rom P12 K.Khun Rat Phinit Chai ai K.Sana Ch P11 K.Charoen Rad m P20 K.Samrong K.Bang Pla P21 K.Dan K.Phithaya Longkon K.Sappasamith P10 K.Chai Talae P1 P2 P3 P5 P6 P7 P8 P9 The Gulf of Thailand Source: Panya Consultants Figure K1.2-2 Schematic Diagram of the Model in 1995 Legend River Wang River Yom River Canal (Khlong, K.) Bhumibol Dam Reservoir Sirikit Dam Barrage Upper Khwae Noi River Pumping Station Bathymetry Ping Dike Riv r er Rive Nan Nakhon Sawan Chain Schematic Diagram in 2002 at-Pa hin R iver sak T ha C Chao Phraya Dam iver (Barrage) ak R Pasak Chonlasit Dam er Pas Riv yok n Na K.Ra kho Ayutthaya phi Na Rama VI Barrage Phat K.Mae Nam Nok Tok Chao Phraya River hat Yaek Prayun S ak ive r K.Raphi P K.13 K.14 K.Rangsit P17 gR kon Pa K.1 P16 g an K.16 Sai Lang B K.14 K.15 a K.13 P19 K.Hok W P15 K.2 K.21 K.Omm Bangkok Noi Tha Chin River i P14 K.Bang Ya K.17 K.14 K.15 K.16 K.San Saeb K.8 wat P25 K.Maha Sa K.Nakhon Nuea Bang Pakong River Saeb ng Khet P13 K.San K.Phra-Ong Chao Bangkok Chaiyanuchit aroen K.Lat Krabang K.Phasi Ch K.Bangkok Yai K.Prawat Buri Rom P12 K.Khun Rat Phinit Chai P26 Sanam Chai P11 K.Charoen Rad K. K.Samrong P20 K.Bang Pla P27 P21 P28 K.Dan asamith K.Phithaya Longkon K.Sapp K.Chai Talae P10 P1 P2 P3 P5 P6 P7 P8 P9 The Gulf of Thailand Source: Panya Consultants Figure K1.2-3 Schematic Diagram of the Model in 2002 K-8 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation Legend River Wang River Yom River Canal (Khlong, K.) Bhumibol Dam Reservoir Sirikit Dam Barrage Pumping Station Khwae Noi Dam Bathymetry Ping Suvarnabhumi International Riv r er Rive Nan Airport Nakhon Sawan Chain Dike at-Pa Schematic Diagram in 2050 Rive r sak T ha Chin Chao Phraya Dam iver (Barrage) ak R Pasak Chonlasit Dam er Pas Riv k ayo K.Ra nN phi kho Ayutthaya Rama VI Barrage Phat Na K.Mae Nam Nok P18 Tok Chao Phraya River hat Yaek ak r K.Raphi P Prayun S ive K.13 K.14 K.Rangsit P17 gR kon Pa K.1 P16 ng Ba K.16 Sai Lang K.14 K.15 a K.13 P19 K.Hok W P15 K.2 P24 K.21 K.Omm Bangkok Noi Tha Chin River i P14 K.Bang Ya K.17 K.14 K.15 K.16 K.San Saeb K.8 wat P23 P25 K.Maha Sa K.Lat Krabang K.Nakhon Nuea Bang Pakong River Saeb ng Khet P13 K.San K.Phra-Ong Chao Bangkok Chaiyanuchit aroen K.Bangkok Yai K.Phasi Ch Short Cut K.Prawat Buri Rom P22 P12 P26 K.Sanam Chai (Barrage) K.Khun Rat Phinit Chai K.Suvarnabhumi P11 K.Charoen Rad P20 K.Samrong K.Bang Pla P27 P21 P28 K.Dan K.Phithaya Longkon K.Sappasamith P10 K.Chai Talae The Gulf of Thailand P1 P2 P3 P4 P5 P6 P7 P8 P9 Source: Panya Consultants Figure K1.2-4 Schematic Diagram of the Model in 2050 Because of the required mathematical model running time, the used appropriate mesh grid size is 800 x 800 m for MIKE 21 and 100 x 100 m for MIKE 11 GIS. Running MIKE FLOOD of this project takes about 2 to 3 days for each case and for MIKE 11 GIS it takes about 2 to 3 hours to create an inundation map. It should be noted that smaller grid size requires more running time.Accuracy of the simulation depends on that of DEM. However, the accuracy of the prepared DEM is different from area to area because a series of precise maps covering whole inundation area is not available and several series of maps of different accuracies were used. Therefore, accurate simulation results are hardly expected for these areas. Land Subsidence Data/information gathering and analysis of land subsidence indicates that the average land subsidence rate has gradually reduced from 10 cm/year to 1-2 cm/year during 1978-2007. Furthermore, during the last 5 years (2002-2007), the average land subsidence rate has reduced to 0.97 cm/year. Therefore, it is expected that the land subsidence rate would reduce by 10% per year. The accumulated land subsidence during 2002-2050 (48 years) would spatially vary from 5 to 30 cm depending on location. The expected accumulated land subsidence in 2050 is applied to determine the DEM in 2050 and used in the simulation of future scenarios. Climate Change Data obtained from JBIC and Application Climate change data provided by the JBIC are temperature rise, percentage change in mean precipitation, and sea level rise for A1FI and B1 climate change scenarios. The given temperature rises are 1.9 oC and 1.2oC for A1FI and B1 scenario respectively, resulting in evapotranspiration increase of about 5 and 3% respectively. The average basin rainfall increases by 3 and 2% corresponding to A1FI and B1. This increase has been distributed over the basin by using the rainfall pattern in 1995. The sea level rise of 0.29 and 0.19 m, proposed by the JBIC, were adopted in the simulation study of future scenarios. The maximum storm surge was estimated to be 0.61 m at the river mouth. It was derived from the propagation of typhoon Linda track in the Gulf of Thailand, hitting Prachuap Khiri Khan province in 1997. K-9 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation Simulations were carried out for the entire flood season (from July to December). To generate flood hydrographs corresponding to 10, 30, and 100-year return periods of rainfall, frequency analysis of basin rainfall over the Chao Phraya River Basin was carried out. The model simulates flood flow along the river/canal network and flood plain covering the study area including Bangkok to identify the inundation area, water depth, and duration of each established scenario. K1.3 Rainfall-Runoff Model In this study, the Chao Phraya River Basin has been divided into 15 sub-basins based on major water control structures and the natural distribution of its river system. The NAM model of each sub-basin was calibrated by using the observed discharge from nearby gauging stations, applying catchment area proportion. The sub-basin which has no nearby gauging station or is in the delta area, the normal parameter of NAM model was applied. However, all parameters were adjusted again in the HD model calibration. In order to verify the land use change, the calibration was based on 2 periods from April 1995 to March 1999 and from April 1999 to March 2003. These periods contain severe flood historical records. Figure K1.3-1 demonstrates the Chao Phraya River Sub- basins for the NAM model. The catchment areas of sub-basins are shown in Table K1.3-1. Untitled 2200000 2150000 07132 73032 28073 2100000 07013 28013 16022 NAN_UPPER 17012 PING UPPER 2050000 07182 WANG 16013 40013 2000000 70072 07162 16072 70013 YOM 1950000 59022 63162 KHAEWNOI 1900000 39042 59012 63013 39013 36023 NAN_LOWER 1850000 PING_LOWER 38052 12012 36013 1800000 38042 CHAOPHRAYA_WEST_UPPER 12081 1750000 26013 36043 SAKAEKANG 26122 PASAK_UPPER 69132 1700000 04062 19052 CHAOPHRAYA_EAST_UPPER 1650000 56012 60684 60072 19013 CHAOPHRAYA_WEST_LOWER 54192 PASAK_LOWER 54012 60013 1600000 42012 54052 60042 THACHIN 32052 32012 31132 1550000 32062 23012 CHAOPHRAYA_EAST_LOWER 41032 41013 51022 52012 1500000 1450000 400000 500000 600000 700000 800000 Source: Panya Consultants Figure K1.3-1 The Chao Phraya River Sub-basins and the Thiessen Polygon of NAM Model Selected daily rainfall data at 51 gauging stations were used. Figure K1.3-1 shows the intersection of the Thiessen Polygons. The NAM model determined the weighted average rainfall over each sub-basin by the Thiessen method. Sub-basin evapotranspiration was estimated from a nearby daily pan evaporation data at 9 stations by applying factor calibrated by the model. List of the gauge weighting factor of sub-basin average rainfall and the estimated evapotranspiration factor of the used evaporation station is shown in Table K1.3-2. K-10 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation Table K1.3-1 Catchment Area of Sub-basins and Index Stations River Sub-basin NAM Model Name Catchment Nearby Station Factor 2 Area (km ) Name Area (km2) The Upper West of the Chao Phraya River CHAOPHRAYA_WEST_UPPER 1,728.57 The Lower West of the Chao Phraya River CHAOPHRAYA_WEST_LOWER 3,847.03 The Upper East of the Chao Phraya River CHAOPHRAYA_EAST_UPPER 9,974.45 The Lower East of the Chao Phraya River CHAOPHRAYA_EAST_LOWER 4,973.33 The Upper Ping River PING_UPPER 26,386.00 Inflow Bhumibol 26,386.00 1.00 The Lower Ping River PING_LOWER 8,150.87 The Wang River WANG 10,793.23 W.4A 10,507.00 1.03 The Yom River YOM 24,046.87 Y.17 21,415.00 1.12 The Upper Nan River NAN_UPPER 13,130.00 Inflow Sirikit 13,130.00 1.00 The Lower Nan River NAN_LOWER 17,359.07 The Khwae Noi River KHWAENOI 4,193.00 N.40 4,340.00 0.97 The Upper Pasak River PASAK_UPPER 12,935.00 S.9 14,374.00 0.90 The Lower Pasak River PASAK_LOWER 2,690.86 The Sakae Krang River SAKAEKRANG 4,906.52 The Tha Chin River THACHIN 13,477.13 Total 158,591.93 Source: Panya Consultants The NAM model was calibrated for each sub-basin. The initial calibration was derived by using an auto-calibration tool provided within the model. The parameters were calibrated by comparing the simulated discharge from NAM model and the observed discharge from the nearby gauging station. It stepped through various combinations of different parameters, while trying to minimize the root mean square error and improving the water balance to best match. To optimize model parameters, manual calibration is needed. Figure K1.3-2 depicts a structure of the Nam model. SOIL MOISTURE QOF PROFILE OVERLAND FLOW CK1 OF OWP OFC OSAT PN P Ep CK2 IF L Umax SURFACE STORAGE U QIF ROOT I ZONE INTER FLOW DL Ea Lmax LOWER OR ROOT Lmax ZONE L RUN G STORAGE OFF Sy CAFLUX BFu GWPUMP GWL GWL CKBF BF GROUND BASE FLOW WATER GWLBF0 STORAG E DEPTH Source: DHI 2007 Figure K1.3-2 Structure of the NAM Model Comparisons of simulated results and observed data calibrated by NAM model are presented in Figure K1.3-3 to K1.3-14. The results show a good measure of overall performances of the model and correlation between the simulated and observed discharge over the full range of values. K-11 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation Table K1.3-2 Weighting Factor of Rainfall and Evaporation Stations of Sub-basins Sub-catchment CHAO CHAO CHAO CHAO PHRAYA_ PHRAYA_ PHRAYA_ PHRAYA- Rainfall WEST_ WEST_ EAST_ EAST_ PING_ PING_ NAN_ NAN_ KHAEW PASAK_U PASAK_ SAKAE Station UPPER LOWER LOWER UPPER UPPER LOWER WANG YOM UPPER LOWER NOI PPER LOWER KANG THACHIN No. Code 1,882.2 4,188.9 5,415.2 10,860.7 26,187.0 8,377.3 10,807.9 24,114.0 13,108.8 17,377.7 4,202.5 12,782.8 2,844.1 4,904.1 13,513.0 1 12081 0.516 0.000 0.000 0.000 0.000 0.168 0.000 0.000 0.000 0.001 0.000 0.000 0.000 0.413 0.000 2 73032 0.000 0.000 0.000 0.000 0.000 0.000 0.009 0.134 0.001 0.000 0.000 0.000 0.000 0.000 0.000 3 07182 0.000 0.000 0.000 0.000 0.253 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 4 07162 0.000 0.000 0.000 0.000 0.138 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 5 07132 0.000 0.000 0.000 0.000 0.195 0.000 0.014 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 6 07013 0.000 0.000 0.000 0.000 0.151 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 7 16022 0.000 0.000 0.000 0.000 0.016 0.000 0.315 0.051 0.000 0.000 0.000 0.000 0.000 0.000 0.000 8 16072 0.000 0.000 0.000 0.000 0.049 0.003 0.195 0.054 0.000 0.000 0.000 0.000 0.000 0.000 0.000 9 16013 0.000 0.000 0.000 0.000 0.001 0.000 0.353 0.019 0.000 0.000 0.000 0.000 0.000 0.000 0.000 10 17012 0.000 0.000 0.000 0.000 0.080 0.000 0.019 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 11 40013 0.000 0.000 0.000 0.000 0.000 0.000 0.014 0.192 0.059 0.000 0.000 0.000 0.000 0.000 0.000 12 28013 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.019 0.360 0.000 0.000 0.000 0.000 0.000 0.000 13 28073 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.012 0.380 0.000 0.000 0.000 0.000 0.000 0.000 14 70072 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.188 0.153 0.055 0.000 0.000 0.000 0.000 15 70013 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.020 0.013 0.211 0.014 0.000 0.000 0.000 0.000 16 59012 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.149 0.000 0.012 0.000 0.000 0.000 0.000 0.000 17 59022 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.138 0.000 0.002 0.000 0.000 0.000 0.000 0.000 18 63162 0.000 0.000 0.000 0.000 0.119 0.038 0.066 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 19 63013 0.000 0.000 0.000 0.000 0.000 0.375 0.015 0.019 0.000 0.000 0.000 0.000 0.000 0.000 0.000 20 39042 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.056 0.880 0.013 0.000 0.000 0.000 21 39013 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.036 0.000 0.140 0.048 0.000 0.000 0.000 0.000 22 36013 0.000 0.000 0.000 0.002 0.000 0.000 0.000 0.000 0.000 0.086 0.000 0.207 0.000 0.000 0.000 23 36023 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.025 0.003 0.226 0.000 0.000 0.000 24 36043 0.000 0.000 0.000 0.037 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.253 0.000 0.000 0.000 25 12012 0.000 0.000 0.000 0.000 0.000 0.367 0.000 0.047 0.000 0.030 0.000 0.000 0.000 0.000 0.000 26 38042 0.000 0.000 0.000 0.037 0.000 0.000 0.000 0.022 0.000 0.186 0.000 0.000 0.000 0.000 0.000 27 38052 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.087 0.000 0.056 0.000 0.000 0.000 0.000 0.000 28 26122 0.000 0.000 0.000 0.352 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003 0.000 0.000 0.000 29 26013 0.484 0.000 0.000 0.114 0.000 0.049 0.000 0.001 0.000 0.042 0.000 0.000 0.000 0.079 0.000 30 04062 0.000 0.043 0.000 0.096 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.115 0.095 31 69132 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.392 0.098 32 56012 0.000 0.215 0.000 0.120 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 33 54012 0.000 0.000 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.261 0.000 0.000 34 54192 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.049 0.530 0.000 0.000 35 54052 0.000 0.000 0.065 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 36 42012 0.000 0.188 0.086 0.031 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.040 0.000 0.000 37 32012 0.000 0.101 0.088 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 38 32052 0.000 0.000 0.178 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 39 32062 0.000 0.000 0.165 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 40 31132 0.000 0.172 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.038 41 60042 0.000 0.005 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.201 42 60072 0.000 0.022 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.116 43 60684 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.222 44 60013 0.000 0.081 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.102 45 19052 0.000 0.000 0.000 0.056 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.247 0.004 0.000 0.000 46 19013 0.000 0.002 0.000 0.156 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.001 0.164 0.000 0.000 47 52012 0.000 0.042 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.057 48 51022 0.000 0.012 0.100 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 49 23012 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.070 50 41032 0.000 0.000 0.241 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 51 41013 0.000 0.118 0.073 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Sum 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 Evaporation Sta. 425201 455201 455201 425201 327501 376201 328201 330201 331201 378201 378201 379402 379402 425201 425201 Factor 0.75 0.70 0.70 0.75 0.80 1.00 1.00 1.00 1.00 1.00 0.80 1.00 0.80 0.75 0.75 Remark: Rainfall and Evaporation Station Codes refer to Table J2.1-1 and J2.2-2 in Appendix J respectively Source: Panya Consultants’ calculation K-12 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation PING_UPPER, Observed RunOff [m^3/s] PING_UPPER, Simulated RunOff [m^3/s] 1400 1200 1000 800 600 400 200 0 1995 1996 1997 1998 PING_UPPER, Accumulated Qobs. Million [m^3] PING_UPPER, Accumulated Qsim. Million [m^3] 20000 15000 10000 5000 0 1995 1996 1997 1998 Source: Panya Consultants’ calculation Figure K1.3-3 Simulated and Estimated Discharges of the Upper Ping River Basin (1995-1999) (R2 = 0.743 and WBL = -5.8%) WANG, Observed RunOff [m^3/s] WANG, Simulated RunOff [m^3/s] 350 300 250 200 150 100 50 0 1995 1996 1997 1998 WANG, Accumulated Qobs. Million [m^3] WANG, Accumulated Qsim. Million [m^3] 4000 3500 3000 2500 2000 1500 1000 500 0 1995 1996 1997 1998 Source: Panya Consultants’ calculation Figure K1.3-4 Simulated and Estimated Discharges of the Wang River Basin (1995-1999) (R2 = 0.678 and WBL = -19.8%) K-13 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation YOM, Observed RunOff [m^3/s] YOM, Simulated RunOff [m^3/s] 1600 1400 1200 1000 800 600 400 200 0 1995 1996 1997 1998 YOM, Accumulated Qobs. Million [m^3] YOM, Accumulated Qsim. Million [m^3] 20000 15000 10000 5000 0 1995 1996 1997 1998 Source: Panya Consultants’ calculation Figure K1.3-5 Simulated and Estimated Discharges of the Yom River Basin (1995-1999) (R2 = 0.866 and WBL = -1.1%) NAN_UPPER, Observed RunOff [m^3/s] NAN_UPPER, Simulated RunOff [m^3/s] 2500 2000 1500 1000 500 0 1995 1996 1997 1998 NAN_UPPER, Accumulated Qobs. Million [m^3] NAN_UPPER, Accumulated Qsim. Million [m^3] 20000 15000 10000 5000 0 1995 1996 1997 1998 Source: Panya Consultants’ calculation Figure K1.3-6 Simulated and Estimated Discharges of the Upper Nan River Basin (1995-1999) (R2 = 0.831 and WBL = -0.4%) K-14 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation KHWAENOI, Observed RunOff [m^3/s] KHWAENOI, Simulated RunOff [m^3/s] 800 700 600 500 400 300 200 100 0 1995 1996 1997 1998 KHWAENOI, Accumulated Qobs. Million [m^3] KHWAENOI, Accumulated Qsim. Million [m^3] 8000 7000 6000 5000 4000 3000 2000 1000 0 1995 1996 1997 1998 Source: Panya Consultants’ calculation Figure K1.3-7 Simulated and Estimated Discharges of the Khwae Noi River Basin (1995-1999) (R2 = 0.750 and WBL = -0.2%) PASAK_UPPER, Observed RunOff [m^3/s] PASAK_UPPER, Simulated RunOff [m^3/s] 1000 800 600 400 200 0 1995 1996 1997 1998 PASAK_UPPER, Accumulated Qobs. Million [m^3] PASAK_UPPER, Accumulated Qsim. Million [m^3] 12000 10000 8000 6000 4000 2000 0 1995 1996 1997 1998 Source: Panya Consultants’ calculation Figure K1.3-8 Simulated and Estimated Discharges of the Upper Pasak River Basin (1995-1999) (R2 = 0.723 and WBL = -14.9%) K-15 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation PING_UPPER, Observed RunOff [m^3/s] PING_UPPER, Simulated RunOff [m^3/s] 1500 1000 500 0 1999 2000 2001 2002 PING_UPPER, Accumulated Qobs. Million [m^3] PING_UPPER, Accumulated Qsim. Million [m^3] 25000 20000 15000 10000 5000 0 1999 2000 2001 2002 Source: Panya Consultants’ calculation Figure K1.3-9 Simulated and Estimated Discharges of the Upper Ping River Basin (1999-2003) (R2 = 0.778 and WBL = 0.1%) WANG, Observed RunOff [m^3/s] WANG, Simulated RunOff [m^3/s] 400 300 200 100 0 1999 2000 2001 2002 WANG, Accumulated Qobs. Million [m^3] WANG, Accumulated Qsim. Million [m^3] 7000 6000 5000 4000 3000 2000 1000 0 1999 2000 2001 2002 Source: Panya Consultants’ calculation Figure K1.3-10 Simulated and Estimated Discharges of the Wang River Basin (1999-2003) (R2 = 0.721 and WBL = -2.5%) K-16 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation YOM, Observed RunOff [m^3/s] YOM, Simulated RunOff [m^3/s] 1500 1000 500 0 1999 2000 2001 2002 YOM, Accumulated Qobs. Million [m^3] YOM, Accumulated Qsim. Million [m^3] 20000 15000 10000 5000 0 1999 2000 2001 2002 Source: Panya Consultants’ calculation Figure K1.3-11 Simulated and Estimated Discharges of the Yom River Basin (1999-2003) (R2 = 0.765 and WBL = 0.1%) NAN_UPPER, Observed RunOff [m^3/s] NAN_UPPER, Simulated RunOff [m^3/s] 2500 2000 1500 1000 500 0 1999 2000 2001 2002 NAN_UPPER, Accumulated Qobs. Million [m^3] NAN_UPPER, Accumulated Qsim. Million [m^3] 25000 20000 15000 10000 5000 0 1999 2000 2001 2002 Source: Panya Consultants’ calculation Figure K1.3-12 Simulated and Estimated Discharges of the Upper Nan River Basin (1999-2003) (R2 = 0.807 and WBL = 0.2%) K-17 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation KHWAENOI, Observed RunOff [m^3/s] KHWAENOI, Simulated RunOff [m^3/s] 800 700 600 500 400 300 200 100 0 1999 2000 2001 2002 KHWAENOI, Accumulated Qobs. Million [m^3] KHWAENOI, Accumulated Qsim. Million [m^3] 10000 8000 6000 4000 2000 0 1999 2000 2001 2002 Source: Panya Consultants’ calculation Figure K1.3-13 Simulated and Estimated Discharges of the Khwae Noi River Basin (1999-2003) (R2 = 0.713 and WBL = -0.2%) PASAK_UPPER, Observed RunOff [m^3/s] PASAK_UPPER, Simulated RunOff [m^3/s] 1000 800 600 400 200 0 1999 2000 2001 2002 PASAK_UPPER, Accumulated Qobs. Million [m^3] PASAK_UPPER, Accumulated Qsim. Million [m^3] 14000 12000 10000 8000 6000 4000 2000 0 1999 2000 2001 2002 Source: Panya Consultants’ calculation Figure K1.3-14 Simulated and Estimated Discharges of the Upper Pasak River Basin (1999-2003) (R2 = 0.608 and WBL = -1.1%) K-18 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation Table K1.3-3 summarizes the calibrated parameters of the NAM model which represented period 1995-1999 and 1999-2003. Table K1.3-3 Calibrated Parameters of the Nam Model Parameter of Nam Model Water GWLBF0 GWLBF1 Catchment Evaporation 2 River Basin 2 R Balance CQOF Cqlow Cklow Factor CKBF CK1,2 Area (km ) Carea Umax Lmax CKIF (%) TOF TIF TG Sy Parameters for 1995-1999 CHAOPHRAYA_WEST_UPPER 1,728.57 15 150 0.7 1000 24 0.5 0.5 0 2000 1 0.1 10 0 0 10000 0.70 CHAOPHRAYA_WEST_LOWER 3,847.03 15 150 0.7 1000 24 0.5 0.5 0 2000 1 0.1 10 0 0 10000 0.70 CHAOPHRAYA_EAST_UPPER 9,974.45 15 150 0.7 1000 24 0.5 0.5 0 2000 1 0.1 10 0 0 10000 0.70 CHAOPHRAYA_EAST_LOWER 4,973.33 15 150 0.7 1000 24 0.5 0.5 0 2000 1 0.1 10 0 0 10000 0.70 PING_UPPER 26,386.00 19.8 128 0.11 260.6 46.8 0.68 0.01 0.661 3837 1 0.1 10 0 28.0 22371 0.80 0.743 -5.8 PING_LOWER 8,150.87 15.9 129 0.32 246.6 49.9 0.63 0.08 0.041 1350 1 0.1 10 0 0.0 4453 1.00 WANG 10,793.23 19.4 289 0.13 319.6 49.3 0.74 0.46 0.938 2024 1 0.1 10 0 88.1 26349 1.00 0.678 -19.8 YOM 24,046.87 17.8 286 0.51 891.5 49.8 0.97 0.29 0.540 1036 1 0.1 10 0 34.7 29165 1.00 0.866 -1.1 NAN_UPPER 13,130.00 15.0 170 0.85 208.0 49.8 0.78 0.10 0.189 1760 1 0.1 10 0 52.2 23760 1.00 0.831 -0.4 NAN_LOWER 17,359.07 11.4 114 0.79 738.7 49.8 0.99 0.35 0.112 1052 1 0.1 10 0 0 11264 1.00 KHWAENOI 4,193.00 16.7 225 0.71 222.1 49.1 0.86 0.29 0.402 1193 1 0.1 10 0 8.1 16314 0.80 0.750 -0.2 PASAK_UPPER 12,935.00 19.2 292 0.15 613.4 45.8 0.98 0.68 0.800 1006 1 0.1 10 0 9.0 25998 1.00 0.723 -14.9 PASAK_LOWER 2,690.86 18.9 298 0.38 475.6 47.2 0.96 0.42 0.635 1053 1 0.1 10 0 47.2 21533 0.80 SAKAEKANG 4,906.52 15 150 0.7 1000 24 0.5 0.5 0 2000 1 0.1 10 0 0 10000 0.70 THACHIN 13,477.13 15 150 0.7 1000 24 0.5 0.5 0 2000 1 0.1 10 0 0 10000 0.70 TOTAL 158,591.93 Parameters for 1999-2003 CHAOPHRAYA_WEST_UPPER 1,728.57 15 150 0.7 1000 24 0.5 0.5 0 2000 1 0.1 10 0 0 10000 0.70 CHAOPHRAYA_WEST_LOWER 3,847.03 15 150 0.7 1000 24 0.5 0.5 0 2000 1 0.1 10 0 0 10000 0.70 CHAOPHRAYA_EAST_UPPER 9,974.45 15 150 0.7 1000 24 0.5 0.5 0 2000 1 0.1 10 0 0 10000 0.70 CHAOPHRAYA_EAST_LOWER 4,973.33 15 150 0.7 1000 24 0.5 0.5 0 2000 1 0.1 10 0 0 10000 0.70 PING_UPPER 26,386.00 16.9 171 0.34 410.0 47.1 0.21 0.25 0.384 1790 1 0.1 10 0 77.4 18067 0.80 0.778 0.1 PING_LOWER 8,150.87 18.3 104 0.40 231.6 46.3 0.86 0.01 0.038 1364 1 0.1 10 0 0.0 4670 1.00 WANG 10,793.23 19.7 266 0.16 376.6 47.6 0.87 0.27 0.855 1327 1 0.1 10 0 76.1 26547 1.00 0.721 -2.5 YOM 24,046.87 11.6 202 0.80 820.2 21.9 0.91 0.87 0.125 1075 1 0.1 10 0 31.9 27619 1.00 0.765 0.1 NAN_UPPER 13,130.00 18.6 162 0.35 281.8 48.8 0.51 0.21 0.522 1227 1 0.1 10 0 44.0 20920 1.00 0.807 0.2 NAN_LOWER 17,359.07 14.4 101 0.63 299.8 45.5 0.98 0.72 0.014 1064 1 0.1 10 0 0 21926 1.00 KHWAENOI 4,193.00 17.3 148 0.95 717.0 46.7 0.97 0.19 0.352 1247 1 0.1 10 0 26.6 28159 0.80 0.713 -0.2 PASAK_UPPER 12,935.00 19.0 185 0.93 361.1 35.9 0.96 0.43 0.011 1043 1 0.1 10 0 0.0 9557 1.00 0.608 -1.1 PASAK_LOWER 2,690.86 15.6 133 0.94 572.2 49.4 0.98 0.30 0.640 2366 1 0.1 10 0 81.5 20664 0.80 SAKAEKANG 4,906.52 15 150 0.7 1000 24 0.5 0.5 0 2000 1 0.1 10 0 0 10000 0.70 THACHIN 13,477.13 15 150 0.7 1000 24 0.5 0.5 0 2000 1 0.1 10 0 0 10000 0.70 TOTAL 158,591.93 Remark: Umax Max.Water Content in Surface Storage (mm) Lmax Max.Water Content in Root Zone Storage (mm) CQOF Overland Flow Runoff Coefficient CKIF Time Constant for Routing Interflow (hour) CK1,2 Time Constant for Routing Overland Flow (hour) TOF Root Zone Threshold Value for Overland Flow TIF Root Zone Threshold Value for Interflow TG Root Zone Threshold Value for Ground Water Recharge CKBF Time Constant for Routing Base Flow (hour) Carea Change ratio of GW-area to catchment area Sy Change specific yield of groundwater reservoir GWLBF0 Threshold groundwater depth for baseflow GWLBF1 Capillary flux, depth for unit flux Cqlow Lower baseflow, recharge to lower reservoir Cklow Time constant for routing lower baseflow (hour) Source: Panya Consultants’ calculation From 1995-1999, coefficient of determination (R2) of each sub-basin shows a good correlation, ranging between 0.723-0.866 (R2 of 1.0 indicating a perfect match between simulated and observed data). For the water balance error (WBL), the difference between simulated and observed data of each sub-basin ranges between 0.2-19.8% mismatch. K-19 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation Form 1999-2003, coefficient of determination (R2) of each sub-basin shows a good correlation, ranging between 0.608-0.807. The WBL of each sub-basin was mainly between 0.1-2.5% mismatch. The reason of the slightly poor values of R2 and WBL are due to the consistency of historical rainfall and discharge data and also the number of rainfall stations used. K1.4 Hydrodynamic Model Hydrodynamic model of the Chao Phraya River and its tributaries is separated into the upper and the lower basins. The Upper Chao Phraya River Basin applied the MIKE 11 to simulate the flood hydrograph of each climate change scenario in Nakhon Sawan province. The observed water level data at Nakhon Sawan (C.2) is used to be the end boundary condition of the Upper Model and the simulated result is used to be the upstream boundary condition of the Lower Model. The generated discharge hydrographs from the NAM model of sub-basins are also the boundary conditions of both upper and lower models, taking into account the proportion of their catchment areas. The Lower Chao Phraya River Basin applied the MIKE FLOOD (a coupling of MIKE 21 and MIKE 11) and MIKE 11 GIS to simulate the flood inundation mechanism in the delta area of the river basin. The river/canal network in this area is very complicated that only the major components of flood protection system are included in the model. The discharge from drainage area of sub-polder dike is treated to drain directly into the river or canal as it is. The end boundary conditions of MIKE 11 are the sea level at the river mouths and the pumping operations at the end of major drainage canals. The boundary conditions of the MIKE 21 are the calculated discharge and water level from MIKE 11 and the sea level fluctuation at about 5 km from the shore, approximately equaling to the water level at the river mouths. The calculated results at each time step are adjusted automatically to be the same values at the same locations in both of MIKE 11 and MIKE 21 and then carried on in the next time step. K1.4.1 Upper Chao Phraya Model The Upper Chao Phraya River Network in HD module consists of 4 river branches namely Ping, Nan, Khwae Noi and Upper Chao Phraya. The Wang and Yom Rivers join directly the Ping and Nan Rivers. Hence river routing is not required. Detailed description of the river branches in river network is presented in Table K1.4-1. Table K1.4-1 Detailed Description of the River Branches in the Upper Model Chainage (m) No. of No. River Remark Upstream Downstream Distance Cross-section 1 Ping 386,298 687,450 301,152 53 RID 1996 2 Nan 237,950 675,700 437,750 59 RID 1996 3 Khwae Noi 0 87,605 87,605 45 Estimated 4 Upper Chao Phraya -2,309 0 2,309 2 RID 1993 Total 828,816 159 Source: Surveyed by RID and Panya Consultants’ calculation Both upstream and downstream boundary conditions were specified to the model. The boundary condition consists of the generated runoff from rainfall data in sub-basins by the NAM model, daily released discharges at the Bhumibol and Sirikit Dams, and water level at C.2 gauging station. A significant parameter in HD model is the roughness coefficient, Manning’s n. The Manning’s n values were calibrated and verified with the 1995 and 2002 flood data by adjusting the values so that the simulated discharge hydrographs were close to the observed data at C.2 gauging station. The calibration results reveal that the Manning’s n values of the Upper Chao Phraya River Network are mainly in river 0.030 to 0.045 and on river bank & flood plain 0.060 to 0.132. Comparison of simulated result and observed data are presented in Figure K1.4-1. K-20 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation [m^3/s] Discharge at C2 in 1995 5000.0 4800.0 4600.0 4400.0 4200.0 4000.0 3800.0 3600.0 3400.0 3200.0 3000.0 2800.0 Discharge 2600.0 2400.0 2200.0 2000.0 1800.0 1600.0 1400.0 1200.0 1000.0 800.0 600.0 400.0 200.0 21-5-1995 10-7-1995 29-8-1995 18-10-1995 7-12-1995 26-1-1996 16-3-1996 [m^3/s] Discharge at C2 in 2002 4200.0 4000.0 3800.0 3600.0 3400.0 3200.0 3000.0 2800.0 2600.0 Discharge 2400.0 2200.0 2000.0 1800.0 1600.0 1400.0 1200.0 1000.0 800.0 600.0 400.0 200.0 21-5-2002 10-7-2002 29-8-2002 18-10-2002 7-12-2002 26-1-2003 17-3-2003 Source: Panya Consultants’ calculation Figure K1.4-1 Simulated Result and Observed Data at C.2 Gauging Station K1.4.2 Lower Chao Phraya Model The Lower Chao Phraya River and canal network in HD module consists of 3 river branches namely Chao Phraya, Tha Chin, and Pasak and major drainage canals on the left and right banks of the Chao Phraya River or the east and west of Bangkok. Detailed description of rivers and canal branches in the river/canal network is presented in Table K1.4-2. The boundary condition comprises the generated runoff from rainfall data in sub-basins by the NAM model taking into account a proportion of drainage area, flood hydrograph at C.2 simulated from the upper model, sea level at the river mouths and at the end of bathymetry (about 5 km from the shore), and operating conditions at pumping stations. The Manning’s n values were calibrated and verified with 1995 and 2002 flood data by adjusting the values so that the simulated stage hydrographs were close to the observed data at gauging stations. The calibration results reveal that the Manning’s n values of the Lower Chao Phraya River and canal network were mainly in river/canal 0.033 to 0.050 and on river bank and flood K-21 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation plain 0.066 to 0.100. Comparison of the inundation map in 1995 between the study result by CTI Engineering Co., Ltd. (RID, 1999) and this study is shown in Figure K1.4-2. 620000 640000 660000 680000 700000 1580000 1580000 1560000 1560000 Pathum Thani ! ( 1540000 1540000 Nonthaburi ! ( Nakhon Pathom ( ! Bangkok ! ( 1520000 1520000 Samut Prakan ! ( 1500000 1500000 Samut Sakhon ! ( 1480000 1480000 620000 640000 660000 680000 700000 Legend ( ! Province Province Boundary -1 - 0 0-1 8 - 10 10 - 15 10 - 50 50 - 100 0 2 4 Ê 8 12 16 Kilometers River/Canal Network 1-2 15 - 20 100 - 200 Elevation (m.MSL) 2-3 20 - 25 200 - 300 -7 - -5 3-4 > 25 300 - 400 -5 - -3 4-5 Max.Water Depth (cm) > 400 Max.Water Depth -3 - -1 5-8 0 - 10 in 1995 Source: Study result by CTI Engineering Co., Ltd. (RID, 1999) and Panya Consultants’ calculation Figure K1.4-2 Inundation Map in 1995 by CTI Engineering Co., Ltd. and by the Consultant Comparison of the inundation area on November 4, 2002 between the satellite image obtained from the Geo-Informatics and Space Technology Development Agency (Public Organization) or GISTDA and the simulation result from this study is shown in Figure K1.4-3. 620000 640000 660000 680000 700000 RADARSAT-1 (November 4, 2002) 1580000 1580000 1560000 1560000 Pathum Thani ( ! 1540000 1540000 Nonthaburi ( ! Nakhon Pathom ! ( Bangkok ( ! 1520000 1520000 Samut Prakan ( ! 1500000 1500000 Samut Sakhon ( ! 1480000 1480000 620000 640000 660000 680000 700000 Legend ( ! Province Province Boundary -1 - 0 0-1 8 - 10 10 - 15 10 - 50 50 - 100 Ê 0 2 4 8 12 16 Kilometers River/Canal Network 1-2 15 - 20 100 - 200 Elevation (m.MSL) 2-3 20 - 25 200 - 300 3-4 > 25 300 - 400 -7 - -5 4-5 > 400 Water Depth -5 - -3 Water Depth (cm) -3 - -1 5-8 0 - 10 on November 4, 2002 Source: Satellite image from GISTDA and Panya Consultants’ calculation Figure K1.4-3 Inundation Area on Nov 4, 2002 from Satellite Image and Simulation Result K-22 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation Table K1.4-2 Detailed Description of the River and Canal Branches in the Lower Model Chainage (m) No. of No. River/Canal Branch Remark Upstream Downsteam Distance Cross-section 1 Upper Chao Phraya (part 1) -2,309 100,000 102,309 43 RID 1983 Upper Chao Phraya (part 2) 0 129,240 129,240 47 RID 1983 Lower Chao Phraya (part 1) 0 98,200 98,200 89 RID 2002 Lower Chao Phraya (part 2) 226,340 274,980 48,640 14 RID 1983 Total Chao Phraya 378,389 193 2 Chao Phraya Shot Cut 0 720 720 5 Estimated 3 Upper Tha Chin 0 115,910 115,910 31 RID 1989 Lower Tha Chin 0 201,000 201,000 201 RID 1989 Total Tha Chin 316,910 232 4 Upper Pasak 432,990 543,263 110,273 18 RID 1998 Lower Pasak 0 47,890 47,890 14 RID 1983 Total Pasak 158,163 32 5 Khlong Chainat-Pasak 0 132,657 132,657 4 Estimated 6 Canal in the Chao Phraya Right Bank Khlong Omm Bangkok Noi 0 24,500 24,500 16 RID 1983 Khlong Bangkok Yai 0 11,550 11,550 9 RID 1983 Khlong Bang Yai 0 12,400 12,400 4 RID 1983 Khlong Young 0 9,600 9,600 4 RID 1983 Khlong Mahasawat 0 26,650 26,650 5 RID 1983 Khlong Phasi Charoen 0 27,500 27,500 6 RID 1983 Khlong Sappasamith-Phithaya Longkon -15 33,400 33,415 7 RID 1983 Khlong Sanam Chai 0 35,485 35,485 9 Estimated Khlong Khun Rat Phinit Chai 0 15,650 15,650 7 Estimated Total 196,750 67 7 Canal in the Chao Phraya Left Bank Khlong Raphiphat 0 60,400 60,400 62 RID 2004 Khlong Raphiphat Yaek Tok 12,000 36,600 24,600 26 RID 2004 Khlong Hokwa Sai Bon 0 8,181 8,181 2 Estimated Khlong Chiang Rak Noi 0 9,896 9,896 3 Estimated Khlong 1 3,705 13,999 10,294 2 Estimated Khlong 1 14,000 21,000 7,000 8 RID 2001 Khlong Mae Nam Nok 0 23,675 23,675 8 Estimated Khlong 14 0 49,560 49,560 45 RID 2003 Khlong Rangsit -7,343 6,300 13,643 13 RID 2003 Khlong Rangsit -47,690 -7,344 40,346 4 Estimated Khlong 2 18,201 24,550 6,349 2 Estimated Khlong 13 -500 12,500 13,000 15 RID 2003 Khlong 15 -450 26,985 27,435 30 RID 2003 Khlong 16 -245 29,000 29,245 32 RID 2003 Khlong 17 0 14,600 14,600 16 RID 2003 Khlong 21 0 16,700 16,700 2 Estimated Khlong 33 0 600 600 2 Estimated Khlong Hokwa Sai Lang -27,750 -1 27,749 3 Estimated Khlong Hokwa Sai Lang 0 26,000 26,000 28 RID 2003 Khlong 8 31,301 44,100 12,799 4 Estimated Khlong Saen Saeb 2,000 44,724 42,724 31 RID 2003 Khlonh Saen Saeb -29,420 1,999 31,419 5 Estimated Khlong Tan 0 3,606 3,606 2 Estimated Khlong Sam Prawet -900 10,900 11,800 3 RID 2003 Khlong Nakhon Nueang Khet 0 27,900 27,900 28 RID 2003 Khlong Phra Ong Chao Chaiyanuchit 14,600 48,600 34,000 37 RID 2003 Khlong Prawet Buri Rom -14,400 0 14,400 17 RID 2006 Khlong Prawet Buri Rom 2,500 25,000 22,500 25 RID 2003 Khlong Prawet Buri Rom -34,982 -14,401 20,581 3 Estimated Khlong Bang Phli 0 14,575 14,575 19 RID 2003 Khlong Chorakae 0 1,939 1,939 4 RID 2003 Khlong Chorakhe 1,940 12,800 10,860 15 RID 2006 Khlong Chorakae 12,801 17,764 4,963 13 RID 2003 Khlong Bang Chalong 0 13,700 13,700 17 RID 2003 Khlong Samrong 1,000 36,606 35,606 20 RID 2003 Khlong Samrong -15,500 999 16,499 3 Estimated Khlong Bang Khli 0 11,760 11,760 13 RID 2006 Khlong Bangpla 0 10,850 10,850 9 RID 2003 Khlong Charoenrad 0 11,000 11,000 14 RID 2003 Khlong Dan 49,600 63,600 14,000 17 RID 2003 Khlong Samrong-Chai Talae 0 12,000 12,000 4 RID 2005 Khlong Chai Talae -15,775 -1 15,774 3 Estimated Khlong Chai Talae 0 17,800 17,800 20 RID 2003 Khlong Mai 17,800 24,300 6,500 9 RID 2005 Khlong Chai Talae 24,300 41,900 17,600 19 RID 2003 Total 846,428 657 Grand Total 2,030,017 1,190 Source: Surveyed by RID and Panya Consultants’ calculation K-23 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation Comparison of stage hydrographs between simulated and observed data is presented in Figure K1.4-4 (m.MSL) C3 ( m.MS L) C7A (m.MSL) (m.MSL) (m.MSL) C4 C22 C12 3.0 2.5 12.0 8 .0 2.5 7 .0 2.5 2.0 10.0 6 .0 2.0 5 .0 2.0 8.0 1.5 4 .0 1.5 1.5 6.0 3 .0 1.0 2 .0 1.0 4.0 1.0 1 .0 0.5 0 .0 0.5 1-7-1995 9-10-1995 1-7 -1 99 5 9 -10 -1 99 5 1-7-1995 3-7-1995 30-12-1995 1-7-1995 29-12-1995 9-10-1995 (m.MSL) Maha Sawat Legend River Calculated Wang River Canal (Khlong, K.) Yom River 2.5 Reservoir Observed Bhumibol Dam Sirikit Dam Barrage Upper Khwae Noi River Pumping Station Bathymetry 2.0 Ping Rive Rive r Dike River k r Nan asa (m.MSL) er P Phraya Banlu Nakhon Sawan at-Pa Chain Upp Schematic Diagram in 1995 1.5 n River sak 3.5 Tha Chi Chao Phraya Dam er (Barrage) a k Riv er Pas Riv yok n Na K.Ra kho 1.0 3.0 Ayutthaya phi Rama VI Barrage Phat Na k K.Mae Nam Nok at ek To Chao Phraya River Ya k er K.Raphi Ph Prayun Sa Riv K.13 K.14 K.Rangsit P17 ong 2.5 Pak K.1 P16 g Ban K.16 P19 Sai Lang K.14 K.15 K.13 1-7-1995 30-12-1995 K.Hok Wa P15 K.2 K.21 K.Omm Bangkok Noi Tha Chin River P14 K.Bang Yai K.14 K.15 K.16 K.17 2.0 MIKE 11 & K.San Saeb K.8 wat K.Maha Sa K.Nakhon Nuea Bang Pakong River Saeb ng Khet P13 K.San K.Phra-Ong Chao Bangkok MIKE 21 in 1995 1.5 Chaiyanuchit roen K.Bangkok Yai K.Lat Krabang K.Phasi Cha P12 Calibration K.Prawat Buri Rom K.Khun Rat Phinit Chai i K.Sanam Cha P11 K.Charoen Rad P20 K.Samrong K.Bang Pla P21 K.Dan K.Phithaya Longkon K.Sappasamith P10 K.Chai Talae 1-7-1995 29-12-1995 P1 P2 P3 P5 P6 P7 P8 P9 The Gulf of Thailand (m.MSL) C3 (m.MSL) C7A (m.MSL) C22 (m.MSL) C12 (m.MSL) C4 2.5 8.0 2.0 12.0 2.0 7.0 1.8 2.0 10.0 6.0 1.6 5.0 1.5 8.0 1.4 4.0 1.5 1.2 6.0 3.0 1.0 1.0 2.0 1.0 4.0 0.8 1.0 0.6 2.0 0.0 0.5 0.5 1-7-2002 9-10-2002 1-7-2002 9-10-2002 1-7-2002 9-10-2002 1-7-2002 30-12-2002 2-7-2002 30-12-2002 (m.MSL)Hokwa Sai Lang Legend Calculated River Wang River Canal (Khlong, K.) Yom River 1.6 Observed Bhumibol Dam Sirikit Dam Reservoir Barrage 1.4 Upper Khwae Noi River Pumping Station Bathymetry 1.2 Ping Dike Rive River r Nan 1.0 Nakhon Sawan Chain Schematic Diagram in 2002 at-Pa 0.8 r sak in Rive Tha Ch Chao Phraya Dam iver 0.6 (Barrage) ak R Pasak Chonlasit Dam er Pas Riv (m.MSL) ayo k Saen Saeb nN 0.4 K.Ra kho Ayutthaya phi Na Rama VI Barrage Phat 0.2 K.Mae Nam Nok at Yaek To k 1.2 Chao Phraya River hi Ph Sak er ap t Prayun Riv K.13 K.14 K.R K.Rangsi P17 ng 2-7-2002 29-12-2002 ako K.1 P16 gP 1.0 Ban K.16 Sai La ng K.14 K.15 K.13 P19 K.Hok Wa P15 K.2 K.21 K.Omm Bangkok Noi Tha Chin River P14 0.8 K.Bang Yai K.14 K.15 K.16 K.17 K.San Saeb K.8 at P25 K.Maha Saw K.Nakhon Nueang Bang Pakong River Saeb Khet P13 0.6 K.San K.Phra-Ong Chao Verification in 2002 Bangkok Chaiyanuchit aroen K.Lat Krabang K.Phasi Ch K.Bangkok Yai K.Prawat Buri Rom P12 0.4 K.Khun Rat Phinit Chai P26 K.Sanam Chai P11 K.Charoen Rad P20 K.Samrong K.Bang Pla P27 P28 P21 0.2 K.Dan ith K.Phithaya Longkon K.Sappasam K.Chai Talae P10 P1 P2 P3 P5 P6 P7 P8 P9 1-7-2002 9-10-2002 The Gulf of Thailand Source: Panya Consultants’ calculation Figure K1.4-4 Stage Hydrographs of Simulated and Observed Data at Gauging Stations K-24 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation As seen in the figures, the calibration results are generally good enough. For 1995 and 2002 floods, in particular, the hydrographs and the inundation maps show a good match with the observed ones. However, considerable gaps between the estimated and observed discharges, water levels, and inundation areas are found. These gaps might be attributed to the racking and accuracy of obtained data. However, in conclusion, the developed model is considered to be acceptable and applicable to the simulation study of the established scenarios. K2 SIMULATION K2.1 Return Periods A return period, also known as a recurrence interval, is an estimate of the interval of time between events of a certain intensity or size. It is a statistical measurement denoting the average recurrence interval over an extended period of time or the inverse of the probability that the event will be exceeded in any one year. For example, a 10-year flood has a 1 / 10 = 0.1 or 10% chance of being exceeded in any one year. It is important to remember that a return period is an average frequency, not a schedule. In the study, 10, 30 and 100-year return periods of rainfall are considered. A 30-year return period of rainfall is a frequency of rainfall events occurring with a magnitude similar to the flood of 1995. K2.2 Scenarios In developing the scenarios, the future changes of precipitation, sea level rise, land subsidence and storm surge were determined as follows: 1) Precipitation: (1) Based on past precipitation records; 10, 30, and 100-year return period basin precipitation as determined by the Consultant. (2) The future basin precipitation was determined by multiplying the precipitation by a factor provided by JBIC for climate change of A1FI and B1 scenarios. (3) The basin precipitation was distributed at rainfall stations according to the rainfall distribution pattern in 1995. 2) Land subsidence: The future land subsidence was analyzed using past data by the Consultant. 3) Sea level rise: The future sea level rise was provided by JBIC for climate change in A1FI and B1 scenarios. 4) Storm surge: The storm surge was based on the historical data collected and analyzed by the Consultant. Scenarios for infrastructure were considered as follows: 1) Current condition (2008), existing and nearly completed flood protection infrastructures; 2) Future condition (2050) with land subsidence, assuming the planned flood protection infrastructures will have been implemented; 3) Future condition mentioned in 2) with climate change A1FI and B1 scenarios; 4) Future condition mentioned in 3) with storm surge; and In the future, when land subsidence, sea level rise, increasing precipitation, and storm surge are considered, the flood protection infrastructures (both existing and planned) may not be enough to protect the area of Bangkok and its vicinities. Therefore, the structural measures such as additional height of crest dikes, increasing pumping capacities, improved drainage canals, etc. are proposed to strengthen the flood protection scheme against the climate change in hydrology. The combination scenarios were considered and summarized as shown in Table K2.2-1. K-25 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation Table K2.2-1 Scenarios for Simulation Study Flood from Precipitation at Return Period Description 10 year 30 year 100 year 1. Current 2008 C2008-T10 C2008-T30 C2008-T100 2. Future in 2050 with land subsidence C2050-LS-T10 C2050-LS-T30 C2050-LS-T100 3. Future in 2050 with land subsidence, C2050-LS-SR-A1F1- C2050-LS-SR-A1F1-T10 C2050-LS-SR-A1F1-T30 sea level rise, and A1FI T100 4. Future in 2050 with land subsidence, C2050-LS-SR-B1-T10 C2050-LS-SR-B1-T30 C2050-LS-SR-B1-T100 sea level rise, and B1 5. Future in 2050 with land subsidence, C2050-LS-SR-SS-A1F1- C2050-LS-SR-SS-A1F1- C2050-LS-SR-SS-A1F1- sea level rise, storm surge, and A1FI T10 T30 T100 6. Future in 2050 with land subsidence, C2050-LS-SR-SS-B1- sea level rise, storm surge, and B1 T100 Source: Panya Consultants’ calculation K2.3 Flood from the Upper Chao Phraya River Basin In the Upper Chao Phraya River Basin in its current condition and in the future, it is assumed that the Khwae Noi Dam is operated apart from the existing Bhumibol and Sirikit Dams. The Upper Model was applied to simulate the flood hydrographs in Nakhon Sawan (C.2) which were used to be the upper boundary conditions of the Lower Model. The Upper Chao Phraya River Basin will be affected by climate change only on increasing of precipitation. Sea level rise and storm surge will not be influent up to the upper basin. As a result of increasing precipitation of 3 and 2% of climate change A1FI and B1 scenarios, the flood volume of each return period is increased at about the same percentage but the increase in flood peak discharge is different due to unequal travel times of flood hydrographs from sub-basins as shown in Table K2.3-1 and Figure K2.3-1. Table K2.3-1 Volume and Peak Discharge of Flood at C.2 and C.13 Gauging Stations 10 year return period 30 year return period 100 year return period Description 1995 T10 T10A1FI T10B1 T30 T30A1FI T30B1 T100 T100A1FI T100B1 C.2 Gauging Station Flood Volume (MCM) 28,307 24,480 25,101 24,953 31,258 32,200 31,965 39,960 41,150 40,839 Factor Increase 1.00 1.03 1.02 1.00 1.03 1.02 1.00 1.03 1.02 3 Flood Peak (m /sec) 4,820 3,143 3,212 3,196 4,801 5,054 4,976 6,853 7,146 7,065 Factor Increase 1.00 1.02 1.02 1.00 1.05 1.04 1.00 1.04 1.03 C.13 Gauging Station Flood Volume (MCM) 24,744 20,320 20,795 20,695 27,756 28,485 28,235 36,997 38,378 38,019 Factor Increase 1.00 1.02 1.02 1.00 1.03 1.02 1.00 1.04 1.03 3 Flood Peak (m /sec) 4,501 2,935 3,000 2,984 4,484 4,720 4,646 6,399 6,673 6,598 Factor Increase 1.00 1.02 1.02 1.00 1.05 1.04 1.00 1.04 1.03 Remark: Flood volume is accumulated from July to December Source: Panya Consultants’ calculation and the recorded data in 1995 by RID The runoff in Nakhon Sawan (C.2) flows to the Chao Phraya Barrage in Chai Nat province for 102 km and some of it is diverted into the Tha Chin River and Khlong Chai Nat-Pasak by the head regulators controlled by the RID. Therefore, the released discharge downstream of the Chao Phraya Barrage is controlled by the RID. The C.13 gauging station is located downstream of the barrage and the recorded runoffs are normally less than that at C.2 because of the diversion upstream, but the shape of the discharge hydrograph is close to that at C.2. K-26 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation 6,000 1995 T10 5,000 T10A1FI T10B1 4,000 Discharge (m /sec) 3 3,000 2,000 1,000 0 1/7 31/7 30/8 29/9 29/10 28/11 28/12 Day/Month 6,000 1995 T30 5,000 T30A1FI T30B1 4,000 Discharge (m /sec) 3 3,000 2,000 1,000 0 1/7 31/7 30/8 29/9 29/10 28/11 28/12 Day/Month 8,000 1995 7,000 T100 T100A1FI 6,000 T100B1 5,000 Discharge (m3/sec) 4,000 3,000 2,000 1,000 0 1/7 31/7 30/8 29/9 29/10 28/11 28/12 Day/Month Source: Panya Consultants’ calculation and the recorded data in 1995 by RID Figure K2.3-1 Flood Hydrographs at Nakhon Sawan (C.2) in Different Scenarios K-27 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation K2.4 Flood in the Lower Chao Phraya River Basin In the Lower Chao Phraya River Basin at current conditions, it is assumed that dikes along both banks of the Chao Phraya River, Khlong Maha Sawat and Khlong Bangkok Noi are completed and in the eastern area of Bangkok are protected by extending the flood protection system including the Suvarnabhumi drainage system. (Table K1.2-3, completed in 2009). I In the future, it is assumed that the diversion system that consists of the improvement of Khlong Raphi Phat, Khlong 13, 14, 17 and others, and pumping stations is completed (Table K1.2-3, completed in 2011). T The Lower Model was applied to simulate the flood flow in the delta area to identify the inundation area, flood depth, and flood duration of each established scenario. The inundation area of each flood depth from the simulation results of all scenarios is shown in Table K2.4-1. Table K2.4-1 The Inundation Area in Different Flood Depth from Simulation Results Unit: km2 C2050-LS-SR-SS-A1FI-T100 C2050-LS-SR-SS-A1FI-T10 C2050-LS-SR-SS-A1FI-T30 C2050-LS-SR-SS-B1-T100 C2050-LS-SR-A1FI-T100 C2050-LS-SR-A1FI-T10 C2050-LS-SR-A1FI-T30 C2050-LS-SR-B1-T100 C2050-LS-SR-B1-T10 C2050-LS-SR-B1-T30 Depth of Flood (cm) C2050-LS-T100 C2050-LS-T30 C2050-LS-T10 C2008-T100 C2008-T10 C2008-T30 Bangkok (BMA) 0-10 1.71 2.01 1.88 1.99 1.89 1.71 1.49 2.12 2.02 2.01 3.49 2.41 2.13 2.12 2.05 1.89 10-50 123.34 136.84 151.35 158.37 161.18 180.27 176.36 176.91 170.06 163.14 166.23 157.02 164.03 161.73 156.54 154.27 50-100 55.63 89.05 116.42 128.91 133.44 121.65 154.66 181.13 191.99 201.96 203.56 211.38 225.87 229.17 236.94 240.29 100-200 7.72 13.78 17.96 22.69 21.28 66.61 47.24 137.05 138.80 137.70 147.76 226.69 239.21 238.41 251.38 249.89 >200 7.43 8.12 8.99 9.46 11.11 7.51 9.20 11.71 11.31 12.98 17.33 20.97 23.76 25.11 25.96 27.62 Sub-total 195.84 249.81 296.60 321.42 328.90 377.74 388.95 508.92 514.18 517.79 538.36 618.46 655.01 656.54 672.87 673.97 Samut Prakarn (SPK) 0-10 0.32 0.39 1.02 1.06 1.18 0.97 0.68 1.41 1.59 1.45 1.09 1.29 1.04 1.00 1.19 1.15 10-50 31.70 30.26 35.57 41.63 40.97 34.52 32.18 53.22 56.93 54.97 52.83 61.83 75.55 74.05 81.85 78.91 50-100 40.70 37.80 35.69 36.37 34.95 43.54 38.81 40.71 42.21 44.86 46.77 42.21 41.42 43.31 44.53 50.13 100-200 46.72 47.79 54.13 56.82 50.58 48.35 54.64 58.07 59.31 54.02 53.60 58.13 64.93 59.71 66.07 60.66 >200 43.78 50.57 57.84 60.78 69.83 45.25 53.53 56.20 59.69 71.24 44.04 49.52 55.42 67.83 60.59 72.12 Sub-total 163.22 166.81 184.26 196.67 197.51 172.63 179.85 209.61 219.74 226.55 198.32 212.99 238.36 245.91 254.24 262.97 BMA&SPK 0-10 2.04 2.40 2.90 3.06 3.07 2.68 2.17 3.53 3.61 3.45 4.57 3.70 3.17 3.13 3.24 3.05 10-50 155.04 167.10 186.92 200.00 202.15 214.79 208.54 230.13 226.99 218.11 219.06 218.85 239.58 235.78 238.39 233.18 50-100 96.34 126.85 152.12 165.28 168.38 165.19 193.47 221.84 234.21 246.83 250.33 253.59 267.30 272.49 281.47 290.42 100-200 54.43 61.57 72.09 79.51 71.86 114.96 101.88 195.13 198.11 191.72 201.35 284.82 304.13 298.12 317.46 310.56 >200 51.21 58.70 66.83 70.25 80.94 52.76 62.74 67.91 71.00 84.23 61.36 70.49 79.18 92.94 86.55 99.74 Total 359.06 416.62 480.86 518.09 526.40 550.37 568.80 718.53 733.92 744.34 736.68 831.45 893.36 902.45 927.11 936.94 Difference - 57.56 121.80 159.03 167.34 - 18.43 168.16 183.55 193.97 - 94.77 156.68 165.76 190.42 200.26 Remark: Difference from the current condition (C2008) Source: Panya Consultants’ calculation Current Condition (2008) The total inundation areas of Bangkok and Samut Prakarn are 359.06, 550.37, and 736.68 km2 for the flood at 10, 30 and 100-year return period respectively. The dike along both banks of the Chao Phraya River directly affects the water level in the river. Considering the same discharge, the water level with the dike is higher than that without. Therefore, the water level in the Chao Phraya River will be higher when a flood at a higher return period occurs. The tide from the Gulf of Thailand affects the water level in the Chao Phraya River but only in high tide periods from October to December. Future with Land Subsidence (2050) Land subsidence will increase the inundation area. For a flood at a 30-year return period that has the probability to occur as did the one in 1995, the total inundation area increases from 550.37 km2 in 2008 to 568.80 km2 in 2050 or about 3.35%. K-28 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation Future with Climate Change The increase in precipitation and sea level rise from climate change A1FI and B1 scenarios will result in increasing inundation areas. For example, for a flood at the 30-year return period, the total inundation area will increase from 550.37 km2 in 2008 to 733.92 km2 in 2050 or 33.35% for A1FI and to 718.53 km2 or 30.55% for B1. Future with Storm Surge and Climate Change The increase in sea level from storm surge plus climate change scenarios will result in an increased inundation area. It is found that for a 30-year return period flood, the total inundation area will increase from 550.37 km2 in 2008 to 744.34 km2 in 2050 or 35.24% for A1FI (1.89% by storm surge). Figure K2.4-1 illustrates a comparison of maximum flood water depth between the current condition (C2008-T30) and the future with land subsidence, sea level rise, and a precipitation increase of 3% (C2050-LS-SR-A1FI-T30) for floods at a 30-year return period. Because of the flood protection system (polder dike and pumping system), most of the areas east of Bangkok will be protected except some areas where the crest elevations of dikes are not high enough, especially in the north and east of the area. For the western area of Bangkok, the crest elevations of dikes are not high enough to protect against flood and sea level rise, especially in the west and south of the area. In addition, the capacity of pumping stations of Phrasi Charoen, Sanam Chai, and Khun Rat Pinitchai are inadequate to pump the inside flood water out into the Tha Chin River and the Gulf of Thailand. 620000 640000 660000 680000 700000 620000 640000 660000 680000 700000 1580000 1580000 1580000 1580000 1560000 1560000 1560000 1560000 Pathum Thani Pathum Thani ( ! ! ( 1540000 1540000 1540000 1540000 Nonthaburi Nonthaburi ( ! ( ! Nakhon Pathom Nakhon Pathom ( ! ( ! Bangkok Bangkok ( ! ( ! 1520000 1520000 1520000 1520000 Samut Prakan Samut Prakan ! ( ( ! 1500000 1500000 1500000 1500000 Samut Sakhon Samut Sakhon ( ! ! ( 1480000 1480000 1480000 1480000 620000 640000 660000 680000 700000 620000 640000 660000 680000 700000 Legend ( ! Province -3 - -1 5-8 0 - 10 Ê 0 2 4 8 12 16 Legend ! ( Province Province Boundary -3 - -1 -1 - 0 5-8 8 - 10 0 - 10 10 - 50 0 2 4 Ê 8 12 16 Province Boundary -1 - 0 8 - 10 10 - 50 Kilometers Kilometers River/Canal Network 0-1 10 - 15 50 - 100 River/Canal Network 0-1 10 - 15 50 - 100 Dike 1-2 15 - 20 100 - 200 Dike 1-2 15 - 20 100 - 200 Elevation (m.MSL) 2-3 20 - 25 200 - 300 Max. Water Depth Elevation (m.MSL) 2-3 20 - 25 200 - 300 -7 - -5 3-4 > 25 300 - 400 Max. Water Depth -7 - -5 3-4 > 25 300 - 400 C2050-LS-SR -5 - -3 4-5 Max. Water Depth (cm) > 400 C2008-T30 -5 - -3 4-5 Max.Water Depth (cm) > 400 -A1FI-T30 Source: Panya Consultants Figure K2.4-1 Maximum Water Depth of Case C2008-T30 and C2050-LS-SR-A1FI-T30 K-29 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation The inundation area on both banks of the Chao Phraya River will expand where the crest elevations of dikes are not high enough. However, the water level will be higher than the crest elevations of dikes along the river banks, but the duration is during the high tide period, so the flood water will not flow into the inner area of Bangkok. Furthermore, the inside drainage system can drain the overflow water into the rivers and the Gulf of Thailand, resulting in less inundation area in the east and the city core of Bangkok. Figure K2.4-2 illustrates an example of the inundation area at various durations in the case future with land subsidence, sea level rise, and precipitation increase of 3% (C2050-LS-SR-A1FI-T30) for flood at 30-year return period. The inundation area in Bangkok and Samut Prakarn will recede after about 4 months but the north of Bangkok in the area of Prathum Thani, Ayutthaya, and up north provinces will recede after about 5-6 months since the flood water can flow into the sea via only the Chao Phraya and Tha Chin Rivers. Moreover, the dikes along the Chao Phraya and Tha Chin Rivers and in the east and west of Bangkok are obstruction to drain the flood water from the north into the sea. Figure K2.4-3 illustrates the maximum water surface profile along the Chao Phraya River from the river mouth to Bang Sai district, Ayutthaya at 10, 30 and 100-year flood return periods. Comparing Case C2008-T100 and C2050-LS-T100, it reveals that the maximum water level will be reduced due to land subsidence of about 0.20 m, considering the sea level at the river mouth is not increased. Comparing Case C2050-LS-T100 and C2050-LS-SR-A1FI-T100, the maximum water level will be increased due to the increasing of flood water from the upper basin and the sea level rise. Comparing Case C2050-LS-SR-A1FI-T100 and C2050-LS-SR-SS-A1FI-T100, the maximum water level will be increased at the river mouth due to storm surge, but the effect will appear up to about 50 km from the river mouth. Figure K2.4-4 to K2.4-6 illustrate the water level variation at four index stations namely (i) Bang Sai, Ayutthaya, (ii) RID Pak Kret, Nonthaburi, (iii) Memorial Bridge, Bangkok, and (iv) Fort Chula at the river mouth, Samut Prakarn at 10, 30 and 100-year return period respectively. As seen in the figures, the flood protection system will cope with the flood at about 10-year return period but inadequate with flood at 30- or 100-year return period. Therefore, the improvement of flood protection system is required to cope with the flood at higher return period in the future. K-30 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation 620000 640000 660000 680000 700000 620000 640000 660000 680000 700000 1580000 1580000 1580000 1580000 1560000 1560000 1560000 1560000 Pathum Thani Pathum Thani ! ( ! ( 1540000 1540000 1540000 1540000 Nonthaburi Nonthaburi ! ( ! ( Nakhon Pathom Nakhon Pathom ! ( ! ( Bangkok Bangkok ! ( ! ( 1520000 1520000 1520000 1520000 Samut Prakan Samut Prakan ! ( ! ( 1500000 1500000 Samut Sakhon 1500000 1500000 Samut Sakhon ! ( ! ( 1480000 1480000 1480000 1480000 620000 640000 660000 680000 700000 620000 640000 660000 680000 700000 Legend ( ! Province -3 - -1 5-8 0 - 10 0 2 4 Ê 8 12 16 Legend ( ! Province Province Boundary -3 - -1 -1 - 0 5-8 8 - 10 0 - 10 10 - 50 0 2 4 Ê 8 12 16 Province Boundary -1 - 0 8 - 10 10 - 50 Kilometers Kilometers River/Canal Network 0-1 10 - 15 50 - 100 River/Canal Network 0-1 10 - 15 50 - 100 Dike 1-2 15 - 20 100 - 200 1 Day Dike 1-2 15 - 20 100 - 200 1 Month Elevation (m.MSL) 2-3 20 - 25 200 - 300 Duration Elevation (m.MSL) -7 - -5 2-3 3-4 20 - 25 > 25 200 - 300 300 - 400 Duration -7 - -5 3-4 > 25 300 - 400 -5 - -3 4-5 1 Day Water Depth (cm) > 400 Water Depth -5 - -3 4-5 1 Month Water Depth (cm) > 400 Water Depth 620000 640000 660000 680000 700000 620000 640000 660000 680000 700000 1580000 1580000 1580000 1580000 1560000 1560000 1560000 1560000 Pathum Thani Pathum Thani ! ( ( ! 1540000 1540000 1540000 Nonthaburi Nonthaburi 1540000 ( ! ( ! Nakhon Pathom Nakhon Pathom ! ( ( ! Bangkok Bangkok ! ( ( ! 1520000 1520000 1520000 1520000 Samut Prakan Samut Prakan ! ( ( ! 1500000 1500000 1500000 1500000 Samut Sakhon Samut Sakhon ! ( ( ! 1480000 1480000 1480000 1480000 620000 640000 660000 680000 700000 620000 640000 660000 680000 700000 Legend ! ( Province Province Boundary -3 - -1 -1 - 0 5-8 8 - 10 0 - 10 10 - 50 0 2 4 Ê 8 12 16 Legend ( ! Province Province Boundary -3 - -1 -1 - 0 5-8 8 - 10 0 - 10 10 - 50 0 2 4 Ê 8 12 16 Kilometers Kilometers River/Canal Network 0-1 10 - 15 50 - 100 River/Canal Network 0-1 10 - 15 50 - 100 Dike 1-2 15 - 20 100 - 200 2 Month Dike 1-2 15 - 20 100 - 200 4 Month Elevation (m.MSL) -7 - -5 2-3 3-4 20 - 25 > 25 200 - 300 300 - 400 Duration Elevation (m.MSL) -7 - -5 2-3 3-4 20 - 25 > 25 200 - 300 300 - 400 Duration -5 - -3 4-5 2 Month Water Depth (cm) > 400 Water Depth -5 - -3 4-5 4 Month Water Depth (cm) > 400 Water Depth Source: Panya Consultants Figure K2.4-2 The Inundation Area in Different Durations (Case C2050-LS-SR-A1FI-T30) K-31 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix K: Mathematical Model Development and Simulation Max.Left or Right Crest Dike 2008 Max.Left or Right Crest Dike 2050 C2008-T10 C2050-LS-T10 C2050-LS-SR-A1FI-T10 6.50 Bang Sai, Ayutthaya 6.00 Max. Water Level in Chao Phraya River at 10-Year Return Period 5.50 RID Pak Kret, Nonthaburi 5.00 4.50 Memorial Bridge, Bangkok Elevation (m.MSL) 4.00 Chao Phraya River Mouth (Fort Chula) 3.50 3.00 2.50 2.00 1.50 1.00 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 Distance (km) Max.Left or Right Crest Dike 2008 Max.Left or Right Crest Dike 2050 C2008-T30 C2050-LS-T30 C2050-LS-SR-A1FI-T30 6.50 Bang Sai, Ayutthaya 6.00 Max. Water Level in Chao Phraya River at 30-Year Return Period 5.50 RID Pak Kret, Nonthaburi 5.00 4.50 Memorial Bridge, Bangkok Elevation (m.MSL) 4.00 Chao Phraya River Mouth (Fort Chula) 3.50 3.00 2.50 2.00 1.50 1.00 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 Distance (km) Max.Left or Right Crest Dike 2008 Max.Left or Right Crest Dike 2050 C2008-T100 C2050-LS-T100 C2050-LS-SR-A1FI-T100 C2050-LS-SR-SS-A1FI-T100 7.00 Bang Sai, Ayutthaya 6.50 Max. Water Level in Chao Phraya River at 100-Year Return Period 6.00 RID Pak Kret, Nonthaburi 5.50 5.00 Memorial Bridge, Bangkok 4.50 Elevation (m.MSL) Chao Phraya River Mouth (Fort Chula) 4.00 3.50 3.00 2.50 2.00 1.50 1.00 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 Distance (km) Source: Panya Consultants’ calculation Figure K2.4-3 Maximum Water Level in the Chao Phraya River at Different Return Periods K-32 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Dike 2008 Dike 2050 C2008-T10 C2050-LS-T10 C2050-LS-SR-A1FI-T10 Dike 2008 Dike 2050 C2008-T10 C2050-LS-T10 C2050-LS-SR-A1FI-T10 7.00 3.50 6.50 6.00 3.00 5.50 Elevation (m.MSL) Elevation (m.MSL) 5.00 2.50 4.50 4.00 2.00 3.50 Bang Sai, Ayutthaya RID Pak Kret, Nonthaburi 3.00 1.50 2.50 Day/Month Day/Month 2.00 1.00 1/7 11/7 21/7 31/7 10/8 20/8 30/8 9/9 19/9 29/9 9/10 19/10 29/10 8/11 18/11 28/11 8/12 18/12 28/12 1/7 11/7 21/7 31/7 10/8 20/8 30/8 9/9 19/9 29/9 9/10 19/10 29/10 8/11 18/11 28/11 8/12 18/12 28/12 Dike 2008 Dike 2050 C2008-T10 C2050-LS-T10 C2050-LS-SR-A1FI-T10 Bank 2008 Bank 2050 C2008-T10 C2050-LS-T10 C2050-LS-SR-A1FI-T10 K-33 3.50 3.00 Appendix K: Mathematical Model Development and Simulation 2.50 3.00 2.00 1.50 Elevation (m.MSL) Elevation (m.MSL) 2.50 1.00 2.00 0.50 Memorial Bridge, Bangkok - 1.50 -0.50 Fort Chula, Chao Phraya River Mouth, Samut Prakarn Day/Month Source: by the Consultant Day/Month 1.00 -1.00 1/7 11/7 21/7 31/7 10/8 20/8 30/8 9/9 19/9 29/9 9/10 19/10 29/10 8/11 18/11 28/11 8/12 18/12 28/12 1/7 11/7 21/7 31/7 10/8 20/8 30/8 9/9 19/9 29/9 9/10 19/10 29/10 8/11 18/11 28/11 8/12 18/12 28/12 Source: Panya Consultants’ calculation Figure K2.4-4 Water Level at Index Stations in the Chao Phraya River at 10-Year Return Period Final Report Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Dike 2008 Dike 2050 C2008-T30 C2050-LS-T30 C2050-LS-SR-A1FI-T30 Dike 2008 Dike 2050 C2008-T30 C2050-LS-T30 C2050-LS-SR-A1FI-T30 7.00 4.00 6.50 3.50 6.00 5.50 3.00 Elevation (m.MSL) 5.00 Elevation (m.MSL) 4.50 2.50 Bang Sai, Ayutthaya 4.00 2.00 3.50 3.00 RID Pak Kret, Nonthaburi 1.50 2.50 Day/Month Day/Month 2.00 1.00 1/7 11/7 21/7 31/7 10/8 20/8 30/8 9/9 19/9 29/9 9/10 19/10 29/10 8/11 18/11 28/11 8/12 18/12 28/12 1/7 11/7 21/7 31/7 10/8 20/8 30/8 9/9 19/9 29/9 9/10 19/10 29/10 8/11 18/11 28/11 8/12 18/12 28/12 Dike 2008 Dike 2050 C2008-T30 C2050-LS-T30 C2050-LS-SR-A1FI-T30 Bank 2008 Bank 2050 C2008-T30 C2050-LS-T30 C2050-LS-SR-A1FI-T30 K-34 3.50 3.00 Appendix K: Mathematical Model Development and Simulation 2.50 3.00 2.00 1.50 Elevation (m.MSL) Elevation (m.MSL) 2.50 1.00 2.00 0.50 Memorial Bridge, Bangkok - 1.50 -0.50 Fort Chula, Chao Phraya River Mouth, Samut Prakarn Day/Month Day/Month 1.00 -1.00 Source: by the Consultant 1/7 11/7 21/7 31/7 10/8 20/8 30/8 9/9 19/9 29/9 9/10 19/10 29/10 8/11 18/11 28/11 8/12 18/12 28/12 1/7 11/7 21/7 31/7 10/8 20/8 30/8 9/9 19/9 29/9 9/10 19/10 29/10 8/11 18/11 28/11 8/12 18/12 28/12 Source: Panya Consultants’ calculation Figure K2.4-5 Water Level at Index Stations in the Chao Phraya River at 30-Year Return Period Final Report Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Dike 2008 Dike 2050 C2008-T100 C2050-LS-T100 C2050-LS-SR-A1FI-T100 C2050-LS-SR-SS-A1FI-T100 Dike 2008 Dike 2050 C2008-T100 C2050-LS-T100 C2050-LS-SR-A1FI-T100 C2050-LS-SR-SS-A1FI-T100 7.00 5.00 6.50 4.50 6.00 4.00 5.50 Elevation (m.MSL) 5.00 3.50 Elevation (m.MSL) 4.50 3.00 Bang Sai, Ayutthaya 4.00 2.50 3.50 2.00 RID Pak Kret, Nonthaburi 3.00 2.50 1.50 Day/Month Day/Month 2.00 1.00 1/7 11/7 21/7 31/7 10/8 20/8 30/8 9/9 19/9 29/9 9/10 19/10 29/10 8/11 18/11 28/11 8/12 18/12 28/12 1/7 11/7 21/7 31/7 10/8 20/8 30/8 9/9 19/9 29/9 9/10 19/10 29/10 8/11 18/11 28/11 8/12 18/12 28/12 Dike 2008 Dike 2050 C2008-T100 C2050-LS-T100 C2050-LS-SR-A1FI-T100 C2050-LS-SR-SS-A1FI-T100 Bank 2008 Bank 2050 C2008-T100 C2050-LS-T100 C2050-LS-SR-A1FI-T100 C2050-LS-SR-SS-A1FI-T100 K-35 3.50 3.50 3.00 Appendix K: Mathematical Model Development and Simulation 3.00 2.50 2.00 Elevation (m.MSL) Elevation (m.MSL) 2.50 1.50 1.00 2.00 0.50 1.50 Memorial Bridge, Bangkok - -0.50 Fort Chula, Chao Phraya River Mouth, Samut Prakarn Day/Month Day/Month 1.00 -1.00 1/7 11/7 21/7 31/7 10/8 20/8 30/8 9/9 19/9 29/9 9/10 19/10 29/10 8/11 18/11 28/11 8/12 18/12 28/12 1/7 11/7 21/7 31/7 10/8 20/8 30/8 9/9 19/9 29/9 9/10 19/10 29/10 8/11 18/11 28/11 8/12 18/12 28/12 Source: Panya Consultants’ calculation Figure K2.4-6 Water Level at Index Stations in the Chao Phraya River at 100-Year Return Period Final Report APPENDIX L IMPACT ASSESSMENT Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix L: Impact Assessment APPENDIX L IMPACT ASSESSMENT L1 METHODOLOGY The impact assessment dealt with the estimation of potential socioeconomic loss due to climate change induced flooding and considered impacts on affected populations, buildings, and infrastructures. For this purpose, the study adopted a methodology based on recommendations of a number of authoritative literature on the subject: Handbook for Estimating the Socio-economic and Environmental Effects of Disasters (ECLAC, 2003), An Assessment of the Socio-Economic Impacts of Floods in Large Coastal Areas (AIT, 2004) and Study on Integrated Plan for Flood Mitigation in Chao Phraya River Basin Report (RID, 1999). The impacts were explored by isolating strategically-important tangible damage related to potential future floods. Intangible damage, which includes negative physiological impact such as fear, depression, mental health, etc., were excluded from impact assessment since it was next to impossible to estimate such psychological conditions within the timeframe of this project. Evaluation of different tangible damages was done considering a number of constraints related to availability of data and information, and the limited timeframe of the project. Thus, this analysis is based on the premise that the impact assessment due to climate change must have a precise understanding of two components of the tangible damage as follows: 1) Direct damage is measurable and often relates to the replacement value of destroyed immovable assets and stocks including final goods, goods in process, raw materials, and spare parts. Direct damages occur at the time of the disaster or within a short time. 2) Indirect damage is not physical but can have negative effect on the economy. Sales loss due to temporary suspension of business or income loss because of failure to operate normal economic activities - are typical examples of indirect damage. They also include disaster-induced increases in current expenditures and in costs for the provision of essential services or lifelines, as well as diminished expected revenues, until normal operating conditions are restored. These occur over a period of month after the disaster has struck, depending on the time required to achieve “normalization” of activities. In slowly evolving disasters, such as the Bangkok flood which occurs over time, most losses are indirect owing to the impact on economic flows, and they will occur for at least as long as the causing phenomena lasts. The main sectors that were assessed for both direct and indirect impacts include: population, building and housing (residential, commercial, and industrial), transportation, water supply and sanitation, energy, and public health. The summary of assessed damages is shown in Table L1-1. Damage costs were assessed for both base year (2008) and climate change scenarios in the future (2050). However, while valuing the damage cost, current (2008) unit costs were applied for both situations. L-1 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix L: Impact Assessment Table L1-1 Summary of Assessed Damage Damage Type Sector Damage Mechanism Direct Damage Residential unit Damage to building and asset Commercial unit Damage to building and asset Industrial unit Damage to building and asset Transportation, Public health, Energy, No direct damage to these infrastructures expected Water supply and sanitation in the future Indirect Damage Population Loss of income Commercial unit Loss of income Industrial unit Loss of income Transportation Negligible loss of revenue Public health Additional cost of medical care Energy Loss of net revenue Water supply and sanitation Loss of net revenue Remark: Only tangible damage taken in the assessment Source: by the Consultant L1.1 Population There are several characteristics of flood that determine the impact severity, e.g. flood depth, duration of inundation, frequency of flood event, and velocity of floodwater or the rate of rising flood. This study considered two major characteristics of flood: flood depth and duration of inundation. Five critical flood depth ranges were categorized based on their effects on the livelihoods of the impacted population (see Table L1.1-1): 1) Depth of 0.00 to 0.10 m (Ankle height); 2) Depth of 0.10 to 0.50 m (Knee height); 3) Depth of 0.50 to 1.00 m (Waist height); 4) Depth of 1.00 to 2.00 m (One story house evacuated); and 5) Depth above 2.00 m (All evacuated). Severity of direct impacts on the population refers to the impairment of daily livelihood activities and can be classified into four levels (see Table L1.1-1): 1) No impact: Negligible inconvenience of daily livelihood activities; 2) Low impact: Minor health problems, some difficulty in living in a single floor house; disrupted vehicular movement brings hardship to regular livelihood activities; 3) Moderate impact: Major health problems requiring medical attention, disrupted mass transit system brings difficulty in accessing daily livelihood needs and necessity to move to upper floor or move out of single floor house; and 4) High impact: Serious impairment of livelihood activities; severe injury and illness requiring hospitalization or even loss of life; evacuation to safer locations. Table L1.1-1 Flood Impact on Population Flood Depth Flood Duration (cm) <1 day 1-7 days 7-15 days 15-30 days > 30 days 0 – 10 No Impact No Impact No Impact No Impact No Impact 10 – 50 Low Low Low Low Moderate 50 – 100 Low Low Moderate Moderate Moderate 100 – 200 Moderate Moderate High High High > 200 High High High High High Source: Adjusted from the Assessment of the Socio-Economic Impacts of Floods in Large Coastal Areas (AIT, 2004) L-2 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix L: Impact Assessment Furthermore, it is evident that not all the people living in flood-prone areas are affected. Therefore, to estimate the number of affected people, it is assumed that 25% in the low impact flood-prone areas are affected while the corresponding percentages for moderate and high flood impact areas are 50 and 75%. Past records on fatalities due to flooding in Bangkok are not available. However, the flood damage record in Thailand (2001-2004) maintained by the Civil Defense Secretariat, the Royal Thai Police, and the Department of Pollution Control show 540 fatalities all over the country. Almost all of these fatalities are due to harsh flooding in other regions outside the BMR. For the BMR, most flood characteristics slowly rise, and it is expected that this type of flooding will not directly cause fatality. So it is assumed that there will be no casualties due to floods in the area. Indirect impact refers to economic hardship of the affected population due to flooding. People may not have access to their work places. They may lose part of their income. However, it is assumed that the salaried population would not be affected by flooding and income loss of self-employed entrepreneurs is included when estimating the commercial sector’s business loss income (see Section 4.1.2). Therefore, only daily wage earners living in condensed communities (slums) would lose income due to flooding. Moreover, it is assumed that people living in a condensed community have income below the poverty line of 68 baht/day/person (NESDB, 2007a). Therefore, indirect impact on the population can be calculated as income loss (at the rate of 68 baht/day/person) of the number of affected condensed community dwellers. L1.2 Buildings and Housing The direct flood damage refers to damage to buildings and housing (residential, commercial and industrial), and assets estimated by the equation below: Direct damage = No. of affected buildings x Damage rate x Unit value of building and asset Damage rate is dependent on the depth of inundation and can be differentiated between damage to building and damage to asset. There is no updated data on the damage rate. The Study on Integrated Plan for Flood Mitigation in Chao Phraya River Basin (RID, 1999) used the survey of the RID in 1997 to estimate the damage rate and recommended that same damage rate can be used irrespective of the type of building and housing (residential, commercial, and industrial). These damage rates were adopted for this study (Table L1.2-1). Table L1.2-1 Flood Damage Rate of Building and Asset Flood Depth Damage Rate (% of value) (cm) Building Asset 0 – 10 0 0 10 – 50 3 1 50 – 100 5 8 100 – 200 7.5 15 > 200 9 19 Source: Adopted from the Study on Integrated Plan for Flood Mitigation in Chao Phraya River Basin Report (RID, 1999) Unit value (average book value) of each type of building was estimated based on unit price used for the assessment of building and construction during the legal right registration of unmovable asset, (B.E.2551-2554 or 2008-2011) (Table L1.2-2) and depreciation rate for Bangkok and Samut Prakarn issued by the Treasury Department (Table L1.2-3). L-3 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix L: Impact Assessment Table L1.2-2 Unit Price of Building and Construction Unit: Baht/m2 Code Type of Building and Construction Bangkok Samut Prakarn 100 Detached house 101 One-storey wooden house 5,950 5,800 102 One-storey raised-floor wooden house 6,150 6,000 103 One-storey concrete house 6,350 6,200 104 Two-storey wooden house 6,100 6,050 105 Two-storey concrete house 6,300 6,200 106 Two-storey half concrete and wooden house 6,150 6,100 107 Three-storey concrete house 6,350 6,200 108 Two-storey concrete twin house 5,950 5,850 109 Three-storey concrete twin house 6,000 5,900 110 One-storey raised-floor wooden Thai-style house 6,800 6,650 111 Two-storey half concrete and wooden Thai-style house 6,800 6,550 200 Town house 201 One-storey town house 6,100 5,900 202 Two-storey town house 6,050 5,900 203 Three-storey town house 6,100 5,950 204 Four-storey town house 6,200 6,050 300 Row house 301 One-storey wooden row house 5,450 5,350 302 Two-storey wooden row house 5,400 5,300 303 Two-storey half concrete and wooden row house 5,300 5,250 400 Commercial Building 401 One-storey commercial building 5,600 5,550 402 Two-storey commercial building 5,650 5,550 403 Two and half-storey commercial building 5,700 5,600 404 Three-storey commercial building 5,750 5,650 405 Three and half-storey commercial building 5,750 5,650 406 Four-storey commercial building 5,950 5,900 407 Four and half-storey commercial building 5,950 5,900 408 Five-storey commercial building 6,050 5,950 409 Six-storey commercial building 6,200 6,100 Source: TRD, 2008 Table L1.2-3 Depreciation Rate of Building and Construction Age of 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 Building and construction (year) Concrete type 1 2 3 4 5 6 7 8 9 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76% through out life time % deduct Concrete and Wood type 2 4 6 8 10 14 18 22 26 30 34 38 42 46 50 55 60 65 70 75 80 85% though out life time % deduct Wood type 3 6 9 12 15 20 25 30 35 40 45 50 55 60 65 72 79 86 93% through out life time % deduct Source: TRD, 2008 The asset value of residential units was estimated based on the possession of durable household appliances of households. Corresponding data were obtained from the Population and Housing Census of 2000. The unit costs of assets were estimated from average market prices. The average asset value based on 12 items for Bangkok and Samut Prakarn is 298,990 and 200,163 baht respectively. Additionally, to account for other assets that are vulnerable to flood damage, the asset value was increased by 10%. Therefore, average unit asset value for Bangkok and Samut Prakarn would be 328,889 and 220,180 baht respectively (Table L1.2-4). L-4 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix L: Impact Assessment Table L1.2-4 Average Book Value of Residential Building and Asset Item Unit Type A* Type B** Type C*** Bangkok Unit cost Baht/m2 6,190 6,475 6,250 2 Average area m 192 192 96 Value of residence Baht/unit 1,188,480 1,243,200 600,000 Depreciation rate 10 year % 10 30 40 Total depreciation Baht/unit 118,848 372,960 240,000 Book value of residential building Baht/unit 1,069,632 870,240 360,000 Proportion of each type % 66 11 23 Average value of residential building Baht/unit 882,865 Average value of asset Baht/unit 328,889 Samut Prakarn Unit cost Baht/m2 6,070 6,325 6,125 Average area m2 192 192 96 Value of residence Baht/unit 1,165,440 1,214,400 588,000 Depreciation rate 10 year % 10 30 40 Total depreciation Baht/unit 116,544 364,320 235,200 Book value of residential building Baht/unit 1,048,896 850,080 352,800 Proportion of each type % 58 11 31 Average value of residential building Baht/unit 810,242 Average value of asset Baht/unit 220,180 Remark: *Type A- concrete or brick; **Type B- concrete or brick and wooden; ***Type C- permanent or non-permanent materials Source: NSO, 2006 For commerce, buildings are categorized into nine groups in accordance with the NSO classification. The book value of each group of commercial building is also obtained from the NSO’s 2006 Business Trade and Services Survey. Description of nine commercial groups with proportion and the book value of building and asset are presented in Table L1.2-5. Table L1.2-5 Average Book Value of Commercial Building and Asset Book value unit: 1,000 Baht Code Description Proportion Building Asset Sale, maintenance and repair of motor vehicles and 50 0.08 494 1,849 motorcycles: retail sale of automotive fuel Wholesale trade and commission trade, except of motor 51 0.09 2,614 6,544 vehicles and motorcycles Retail trade, except of motor vehicles and motorcycles; 52 0.41 655 1,193 repair of personal and household goods 55 Hotels and restaurants 0.15 1,484 706 70 Real estate activities 0.08 23,191 3,082 Renting of machinery and equipment without operator 71 and of personal and household goods 72 0.02 341 3,309 Computer and related activities 73 Research and development 74 Other business activities 0.04 1,771 1,827 92 Recreational, cultural and sporting activities 0.02 1,518 4,920 93 Other service activities 0.11 353 113 Average value of commercial 2,768 1,829 Source: NSO, 2006 In the case of industry, the building is categorized into 11 and 12 groups for Bangkok and Samut Prakarn in accordance with the National Statistic Office (NSO) classification. The book value of each group of industrial building is also obtained from the NSO’s 2007 Industrial Census. Description industrial groups with proportion and the book value of building and asset are presented in Table L1.2-6. It is assumed that the large factories and the factories located in the L-5 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix L: Impact Assessment Industrial Estates, Industrial Zones, Industrial Community, and Industrial Parks would not be affected by flood since these factories are protected from flood damage. Therefore, they were not included in the impact assessment. Table L1.2-6 Average Book Value of Industrial Building and Asset Book value unit: 1,000 Baht Bangkok Samut Prakarn Code Description Pro Book Value Pro Book Value portion Building Asset portion Building Asset 15 Manufacture of food products and beverages 0.062 6,393 5,681 0.047 22,065 33,393 16 Manufacture of tobacco products 17 Manufacture of textiles 0.09 4,637 2,327 0.383 3,014 1,686 18 Manufacture of wearing apparel; dressing and dyeing of fur 0.026 2,407 2,327 Tanning and dressing of leather; manufacture of luggage, handbags, saddler, 19 0.067 2,049 983 harness and footwear Manufacture of wood and of products of wood and cork, except furniture 20 manufacture of articles of straw and plaiting materials 21 Manufacture of paper and paper products 0.058 2,548 2,010 22 Publishing, printing and reproduction of recorded media 0.065 7,353 3,991 23 Manufacture of coke, refined petroleum products and nuclear fuel 24 Manufacture of chemicals and chemical products 0.015 2,548 6,034 0.058 2,548 2,010 25 Manufacture of rubber and plastic products 0.044 4,737 2,010 0.118 4,737 6,118 26 Manufacture of other non-metallic mineral products 0.021 14,378 1,912 27 Manufacture of basic metals 0.03 7,320 1,912 28 Manufacture of fabricated metal products, except machinery and equipment 0.159 2,499 1,614 0.24 2,499 3,652 29 Manufacture of machinery and equipment 30 Manufacture of office, accounting and computing machinery 31 Manufacture of electrical machinery and apparatus n.e.c. 0.035 8,096 6,127 0.112 8,096 6,118 32 Manufacture of radio, television and communication equipment and apparatus 33 Manufacture of medical, precision and optical instruments, watches and clocks 34 Manufacture of motor vehicles, trailers and semi-trailers 0.032 12,144 6,127 0.011 11,144 5,784 35 Manufacture of other transport equipment 36 Manufacture of furniture; manufacturing n.e.c. 0.117 3,313 1,912 0.051 3,313 6,412 37 Recycling Manufacture of wood and of products of wood and cork, except furniture; 20 manufacture of articles of straw and plaiting materials 0.16 4,794 1,912 21 Manufacture of paper and paper products 0.057 5,453 4,337 23 Manufacture of coke, refined petroleum products 26 Manufacture of other non-metallic mineral products 27 Manufacture of basic metals Average value of industry 4.555 3,725 7,787 3,949 Source: NSO, 2007 Indirect damage costs of flooding on commerce and industry refer to the loss of income or business suspension due to flooding. The calculation of the total income loss due to flood damage is as follows: Business income loss = No. of affected buildings x Income/day x Flood duration To estimate the income loss of commerce, data from the NSO’s 2006 Business Trade and Services Survey was used. The average annual value added per commercial establishment was 3,179,406 baht per year or 8,711 baht per day. It is assumed that during business suspension due to flooding 10% of average business operating cost (3,781 baht per day) will not be paid. Therefore, daily income loss of commerce is 4,930 baht per establishment. In the case of income loss of industry, information was obtained from the NSO’s 2007 Industrial Census in Bangkok and its vicinity. The average annual value added per industrial establishment was 7.4 and 23 million baht per year or 20,274 and 63,014 baht per day for Bangkok and Samut Prakarn respectively. It is assumed that during the business suspension due to flooding 10% of average business operating costs (5,601 and 18,971 baht for Bangkok and Samut Prakarn respectively) will not be paid. Therefore, daily income losses of industry are 14,673 and 44,043 baht per establishment in Bangkok and Samut Prakarn respectively. L-6 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix L: Impact Assessment L1.3 Transportation Railway The level of rail lines is generally set at about one meter above the surrounding ground level. The history of flooding in Bangkok chronicles minimal effect on rail transportation. It can be safely assumed that railways will incur minimum damage and will be able to operate normally during and after flooding. Mass Rapid Transit The Mass Rapid Transit System, both elevated and underground, in Bangkok has been designed to be protected from overflow flood water. The elevation of the gates of the Mass Rapid Transit Authority (MRTA) underground Blue Line, linking to the streets, is set at one meter above the street level, and the door to the entrance will be shut down when water rises to one meter above the sidewalk. The Bangkok Mass Transit System Public Company Limited (BTS) elevated Green Line is also safe from high water levels. Waterway Transport Waterway transportation operated in the inner city of Bangkok is not affected by high water levels during flooding periods. Air Transport Both Suvarnabhumi International and Don Muang Airports, connected with land transport by Airport Rail Link and Elevated Expressway, have special measures to protect them from rising flood water. They are not expected to have serious impacts from flooding. Road and Highway More than 90% of inhabitants of Bangkok and Samut Prakarn travel by roads and highways. The road network in Bangkok, Samut Prakarn, and the BMR were set at an elevation at of 1.5-2.0 meters above ground, and most of them were covered with reinforced concrete pavement or 7-10 cm thick of asphaltic pavement. Therefore, they will not incur flood damage caused by rising water in the future and direct impact on these infrastructures can be neglected. H However, there might be indirect impact in terms of loss of revenue due to suspension of operation of inundated toll plazas. This type of indirect impact could be estimated based on loss of operation-days of toll plazas (inundated by more than one meter) and revenue generated by these toll plazas. Nevertheless, it was found that even under the worst case scenario of the future (C2050-LS-SR-SS-A1FI-T100) the flood water depth would remain less than 1 m near all toll plazas and there would be no indirect impact on the road and highway transportation. L1.4 Water Supply and Sanitary System Direct damage to the water supply and sanitary (WSS) infrastructure is not assessed since they are protected from the worst possible flood in the future. Historical records of damage of the WSS system also attest to this statement. Nevertheless, indirect impact which refers to income loss for the water supply system and operating losses of the wastewater treatment system and solid waste management system were estimated. Users were categorized into residential and non-residential based on different demands and sales rates. It is assumed that the water supply system will become dysfunctional when flood water rises two meters above the surrounding ground surface. Subsequently, users in the flooded area will have no service from the water supply system. The calculation of sales loss for the water supply system due to flood damage follows: Water supply sales loss = No. affected users x Water demand per user x Water sales rate x Flood duration L-7 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix L: Impact Assessment The five-year record of the Metropolitan Waterworks Authority (MWA) indicates water sales for a residential unit are 0.48 m3 per day per household and water revenue is 2.06 baht per m3. Water sales for a non-residential unit are 3.71 m3 per day per customer and water revenue is 2.83 baht per m3 With regards to the sanitation system which includes the wastewater treatment system and the solid waste management system, it is assumed that their operation would be suspended when the flood water rises two meters above the surrounding ground surface. The calculation of income loss from non-operation of the sanitation systems due to flooding follows: Sanitation operating loss = No. affected population x Generated rate x Treatment cost x Flood duration According to the Department of Drainage and Sewerage (DDS), the BMA record in 2007: 1) Wastewater generation rate is 0.37 m3 per day per capita (80% of water demand); 2) Wastewater treatment cost is 12.17 baht per m3; 3) Solid waste generation rate is 1 kg per day per capita; and 4) Solid waste disposal cost is 454.75 baht per ton. L1.5 Energy They are two electricity generation plants in Bangkok. The North Bangkok power plant has been already retired, and life of South Bangkok power plant will be expired before 2050. Future power generation plants for Bangkok and Samut Prakarn are planned outside these two cities. Thus, there will be no direct impact to the power generation plants in the future. Concerning electricity distribution, 18 service-districts cover Bangkok, Samut Prakarn and Nonthaburi with 145 substations according to the Metropolitan Electricity Authority (MEA). These substations - buildings and equipments - will not incur direct flood damage since floodwater remains below one meter depth in these Substations. However, the MEA will lose revenue due to service suspension. These indirect damage cost can be estimated from the loss of net revenue that will accrue when electricity supply has to be shut down to areas inundated more than one meter. Corresponding unit electricity sales-loss data were obtained from the MEA (Table L1.5-1). Table L1.5-1 Unit Cost of Electrical Damage by Service-district Unit: million Baht No. of Sub- Consumption Loss of Flood of 1-1.5 m depth Flood of 1.5-2 m depth Service District stations (GWh) Revenue Building Equipment Total Damage Building Equipment Total Damage Bang Bua Thong 4 1,070.00 11.70 - - - 0.40 34.50 34.90 Bang Kapi 11 3,096.30 33.90 0.30 34.00 34.30 1.10 68.00 69.10 Bang Khen 7 2,493.80 27.30 0.15 39.50 39.65 0.70 62.00 62.70 Bang Khun Thian 9 2,216.00 24.30 0.25 24.00 24.25 0.90 48.00 48.90 Bang Phi 9 3,143.00 34.40 0.15 16.00 16.15 0.90 46.00 46.90 Bang Yai 5 1,070.90 11.70 0.15 40.50 40.65 0.50 53.50 54.00 Klong Toei 13 3,728.80 40.90 0.05 8.00 8.05 1.30 83.00 84.30 Lat Phrao 4 1,469.20 16.10 0.05 4.00 4.05 0.40 24.00 24.40 Lat Krabang 5 1,609.00 17.60 0.05 10.50 10.55 0.50 29.00 29.50 Min Buri 5 1,286.70 14.10 0.05 18.00 18.05 0.50 35.50 36.00 Nonthaburi 11 2,652.90 29.10 0.15 26.00 26.15 1.10 69.00 70.10 Prawet 5 1,831.40 20.10 0.10 35.00 35.10 0.40 48.00 48.40 Rat Burana 12 3,957.80 43.40 0.55 76.00 76.55 1.20 86.00 87.20 Samsen 13 3,142.80 34.40 0.25 22.00 22.25 1.30 69.00 70.30 Samut Prakarn 12 4,918.50 53.90 0.60 88.00 88.60 1.20 97.00 98.20 Thon Buri 5 1,480.80 16.20 0.10 8.00 8.10 0.50 33.00 33.50 Wat Liab 6 1,118.10 12.30 0.15 66.00 66.15 0.60 100.50 101.10 Yan Nawa 9 1,749.40 19.20 0.30 32.00 32.30 0.90 58.00 58.90 Total 145 42,035.50 460.70 3.40 547.50 550.90 14.40 1,044.00 1,058.40 Remark: the consumption record in 2007, cost of electrical usage is 4 baht/kWh Source: MEA, 2008 L-8 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix L: Impact Assessment L1.6 Public Health There is no historical record of direct flood damage to public health facilities. However, the health facilities that are vulnerable to flood inundation are identified. Indirect damage cost on public health refers to the additional health care cost due to flooding. During a flood, occurrence of tropical infectious diseases such as acute diarrhea, pneumonia, conjunctivitis, typhoid, and cholera will increase due to the intrusion of waste water and hazardous waste into the living environment. It is assumed that 25% of the population living under 50-100 cm flood depth will be flood- affected while the corresponding percentages for 101-200 cm and >200 cm flood depth conditions will be 50 and 75% respectively. It is further assumed 50 percent of the population affected by flooding will need additional medical attention owing to flood related diseases. Based on average health care costs of 7,582 and 3,786 baht per person per admission in Bangkok and Samut Prakarn, derived in 2005 by the Health and Welfare Survey of the NSO, and the estimated number of people requiring additional medical care, the indirect damage cost on the public health system was estimated. L2 IMPACT ASSESSMENT RESULTS Impacts in terms of estimated damage costs of all scenarios are shown in Table L2-1. Table L2-1 The Damage Cost Estimation Unit: million Baht C2050-LS-SR-SS-A1FI-T100 C2050-LS-SR-SS-A1FI-T10 C2050-LS-SR-SS-A1FI-T30 C2050-LS-SR-SS-B1-T100 C2050-LS-SR-A1FI-T100 C2050-LS-SR-A1FI-T10 C2050-LS-SR-A1FI-T30 C2050-LS-SR-B1-T100 C2050-LS-SR-B1-T10 C2050-LS-SR-B1-T30 Item of Flood Losses C2050-LS-T100 C2050-LS-T30 C2050-LS-T10 C2008-T100 C2008-T10 C2008-T30 Damage Building 12,166 40,277 54,231 63,982 70,058 27,281 75,500 97,761 105,575 113,679 61,037 142,432 170,368 176,328 179,695 188,215 - Residence 7,462 21,500 27,813 31,907 34,465 15,894 37,739 48,746 52,072 55,432 33,557 68,420 80,591 83,312 84,631 88,628 - Commerce 3,254 13,565 19,466 23,828 26,814 8,293 29,250 38,689 42,157 45,945 20,960 61,657 74,194 76,781 78,492 82,147 - Industry 1,450 5,212 6,952 8,247 8,779 3,094 8,511 10,326 11,346 12,302 6,520 12,355 15,583 16,235 16,572 17,440 Income Loss 2,761 11,005 15,875 18,132 20,188 7,069 22,717 29,311 31,533 32,695 14,901 39,854 48,699 50,009 50,223 51,629 - Daily Wage Earner 27 47 71 80 89 92 102 128 137 140 167 176 205 205 205 205 - Commerce 1,315 6,306 9,638 11,138 12,676 4,077 14,940 19,518 20,883 21,671 9,172 27,744 33,963 34,913 34,968 3,508 - Industry 1,264 4,260 5,699 6,394 6,894 2,640 7,066 8,596 9,397 9,726 4,897 9,965 12,174 12,534 12,692 13,158 - Energy 149 383 456 508 517 254 598 1,057 1,104 1,145 659 1,954 2,340 2,340 2,341 2,341 Water Supply & - 6 9 11 12 12 6 11 12 12 13 6 15 17 17 17 17 Sanitation Health Care Cost 321 537 717 825 872 934 1,107 1,665 1,893 2,012 3,240 3,473 4,020 4,020 3,945 4,022 Total 15,248 51,819 70,823 82,939 91,118 35,284 99,324 128,737 139,001 148,386 79,178 185,759 223,087 230,357 233,863 243,866 Increase from C2008 36,571 55,575 67,691 75,870 64,040 93,453 103,717 113,102 106,581 143,909 151,179 154,685 164,688 Source: Panya Consultants’ calculation In general, the largest affected sector would be direct damage of buildings (residential, commercial and industrial), which might account for 78% of the total damage cost. Income loss of the commercial and industrial sectors would account for approximately 14 and 7% of the total damage cost respectively. The additional health care cost would be 2% To address the impact cost due to climate change, two scenarios are highlighted: (i) current condition (C2008-T30), and (ii) future climate change condition (C2050-LS-SR-SS-A1FI-T30). Under the current condition, impact costs would be 35 billion baht which might rise to 148 billion baht in the future climate changed scenario. This marks over a four-fold increase in the impact cost L-9 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix L: Impact Assessment due to the 30-year return period flood under climate forcing corresponding to the A1FI scenario. The increase in impact cost will be a five-fold in between the 10-year return period floods that can occur today (2008) and in 2050 under A1FI climate forcing. The effect of different return period flood on the impact cost is evident. For example, the current damage cost would be 15 billion baht for a 10-year return period flood while the damage cost will increase to 35 and 79 billion baht respectively for 30- and 100-year return period flood. The largest damage in 2050 will be due to land subsidence and will double the current damage costs. Also, storm surge will increase the current damage cost by the lowest margin compared to land subsidence, climate change and sea level rise. Table L2-2 presents incremental damage cost. The cost of damage as a percentage of GDP for the BMA and Samut Prakarn is also given. For 2008 the cost is compared with a GDP of 2,916 billion baht and for 2050 the cost is compared with a GDP of 19,211 billion baht. Table L2-2 Incremental Damage Costs T10 T30 T100 Factors Cost % of Cost as Cost % of Cost as Cost % of Cost as (million base % of (million base % of (million base % of Baht) case GDP Baht) case GDP Baht) case GDP Current Condition 2008 15,248 0.52 35,285 1.21 79,178 2.72 Factor in Year 2050 Land Subsidence 36,572 240 0.19 64,039 181 0.33 106,581 135 0.55 B1 19,003 125 0.10 29,412 83 0.15 37,328 47 0.19 B1& Storm Surge - - - - - - 7,270 9 0.04 A1FI 31,119 204 0.16 39,678 112 0.21 48,104 61 0.25 A1FI & Storm Surge 8,180 54 0.04 9,384 27 0.05 10,003 13 0.05 Source: Panya Consultants’ Calculation L2.1 Affected Population The worst recorded flooding of Bangkok (in terms of flood volume from the upstream catchment) occurred in 1995. Our hydrological simulation indicated that the 30-year return flood volume in 2008 corresponds to the recorded flood volume in 1995. Therefore, comparison of impacts on the population corresponding to the 30-year return period flood in 2008 and 2050 can shed light on the impact of climate change. The assessment results show that in C2050-LS-SR-SS-A1FI-T30 scenario, almost 1 million people in Bangkok and Samut Prakarn are impacted. The impact will be profuse for people living on the lower floor. Nevertheless, people living on higher floors in the Bang Khun Thian district of Bangkok and the Phra Samut Chedi district of Samut Prakarn might also be impacted. The details are shown in Table L2.1-1. District-wise, Don Muang district in north Bangkok has the highest number of people affected by flood (approximately 90,000) owing to its higher population density. In the western part of the Chao Phraya River, about 200,000 people in Bang Khun Thian, Bang Bon, Bang Khae and Nong Kham districts might be impacted. Flood affected population in Bangkok and Samut Prakarn subjected to different duration of flood in various scenarios is presented in Table L2.1-2. L-10 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix L: Impact Assessment Table L2.1-1 Affected Population under C2008-T30 and C2050-LS-SR-SS-A1FI-T30 Scenarios Unit: people C2008-T30 C2050-LS-SR-SS-A1FI-T30 Province/District Moderate High Moderate High Low Impact Total Low Impact Total Impact Impact Impact Impact Bangkok 498,770 63,692 11,732 574,195 645,409 176,175 16,520 838,104 District Bang Bon 36,651 - - 36,651 45,462 2,293 - 47,755 Bang Kapi - - - - - - - - Bang Khae 25,991 - - 25,991 39,326 560 - 39,886 Bang Khen 1,927 47 - 1,973 1,962 603 - 2,565 Bang Kho Laem 36,749 - - 36,749 47,693 - - 47,693 Bang Khun Thian 37,876 5,622 11,694 55,192 46,604 14,068 14,464 75,136 Bang Na 111 - - 111 1,345 - - 1,345 Bang Plat 18,402 - - 18,402 29,852 1,355 - 31,206 Bang Rak 8,950 - - 8,950 11,390 - - 11,390 Bang Su 33,483 309 - 33,792 34,615 12,698 - 47,313 Bangkok Noi 1,948 - - 1,948 5,986 - - 5,986 Bangkok Yai 578 - - 578 1,607 - - 1,607 Bung Kum - - - - - - - - Chatuchak - - - - - - - - Chom Thong 9,648 - - 9,648 14,029 - - 14,029 Din Daeng - - - - - - - - Don Maung 57,554 19,088 - 76,642 58,218 32,091 - 90,309 Dusit 21,579 565 - 22,143 20,449 13,326 - 33,775 Huai Khwang - - - - - - - - Khanna Yao 607 - - 607 395 - - 395 Khlong Sam Wa 7,901 3,396 - 11,297 7,918 8,485 - 16,403 Khlong San 15,218 - - 15,218 27,554 - - 27,554 Khlong Toei - - - - 1,817 - - 1,817 Lak Si 1,809 1,058 - 2,868 10,267 8,717 - 18,983 Lat Krabang 2,194 7,783 5 9,983 3,222 16,331 1,373 20,926 Lat Phrao - - - - - - - - Min Buri 13,417 - - 13,417 11,816 - - 11,816 Nong Chok 13,721 25,604 34 39,358 12,831 43,303 683 56,816 Nong Khaem 28,152 - - 28,152 23,440 20,187 - 43,627 Pathum Wan - - - - - - - - Phasi Charoen 19,172 - - 19,172 21,977 - - 21,977 Phaya Thai - - - - - - - - Phra Kanong 1,343 - - 1,343 4,731 - - 4,731 Phra Nakhon 11,604 - - 11,604 13,415 - - 13,415 Pom Prap Sattruphai - - - - - - - - Prawet 3,352 - - 3,352 3,627 - - 3,627 Rat Burana 25,655 - - 25,655 30,998 - - 30,998 Rat Thewi - - - - - - - - Sa Thon 3,774 - - 3,774 17,710 - - 17,710 Sai Mai 13,947 221 - 14,169 17,710 464 - 18,174 Samphanthawong 6,219 - - 6,219 9,029 - - 9,029 Saphan Sung 692 - - 692 298 - - 298 Suan Luang - - - - - - - - Taling Chan - - - - 1,896 - - 1,896 Thawi Watthana - - - - 726 - - 726 Thon Buri 21,620 - - 21,620 24,390 - - 24,390 Thung Khu 13,156 - - 13,156 13,705 1,695 - 15,400 Wang Thong Lang - - - - - - - - Watthana - - - - - - - - Yan Nawa 3,768 - - 3,768 27,399 - - 27,399 Samut Prakarn 9,355 12,033 12,988 34,376 24,927 26,763 35,492 87,183 Amphoe Bang Bo 2,201 2,052 655 4,908 3,117 2,216 4,756 10,090 Bang Phi 0 - - 0 106 - - 106 Muang Samut Prakarn 54 324 159 537 4,118 2,552 1,990 8,659 Phra Pradaeng 171 112 - 284 6,351 246 - 6,597 Phra Samut Chedi 6,749 9,544 12,174 28,467 10,998 21,749 28,746 61,494 Bang Sao Thong 180 - - 180 237 - - 237 Source: Panya Consultants’ calculation L-11 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix L: Impact Assessment Table L2.1-2 Affected Population in Various Scenarios Unit: people Affected Duration of Flood at T30 Duration of Flood at T100 Population <1 day 1-7 day 7-15 day 15-30 day > 30 day <1 day 1-7 day 7-15 day 15-30 day > 30 day C2008 Low Impact 508,125 505,052 495,859 484,535 474,127 717,194 715,676 711,881 706,542 690,093 Moderate Impact 75,725 73,653 71,494 68,214 62,570 326,124 323,778 320,352 317,013 301,049 High Impact 24,721 23,854 19,978 15,876 10,051 27,603 26,564 22,632 18,368 11,102 Total 608,571 602,558 587,330 568,624 546,748 1,070,921 1,066,018 1,054,866 1,041,923 4,233,727 C2050-LS Low Impact 567,896 566,499 560,084 547,521 532,894 719,884 719,402 714,796 710,781 698,021 Moderate Impact 72,606 71,785 66,002 60,863 51,864 446,004 443,181 435,640 426,218 414,070 High Impact 44,357 41,110 31,238 25,339 18,115 57,464 53,234 41,555 36,087 26,143 Total 684,859 679,394 657,324 633,723 602,873 1,223,351 1,215,817 1,191,992 1,173,086 4,804,246 C2050-LS-SR-B1 Low Impact 652,513 648,767 646,187 640,791 621,317 716,978 710,365 707,659 704,762 704,265 Moderate Impact 161,268 159,830 157,796 149,110 164,160 500,712 494,515 484,169 476,787 453,503 High Impact 48,295 43,327 34,628 27,536 19,578 65,044 59,080 45,893 38,537 30,038 Total 862,076 851,924 838,612 817,438 805,055 1,282,734 1,263,961 1,237,721 1,220,086 5,004,501 C2050-LS-SR-A1FI Low Impact 808,878 808,410 803,716 789,026 771,643 794,354 793,785 785,450 784,159 778,913 Moderate Impact 193,573 192,025 187,844 173,946 163,766 504,993 495,359 483,955 476,888 461,805 High Impact 50,871 44,379 35,853 26,732 18,980 65,600 59,181 45,872 38,545 30,588 Total 1,053,322 1,044,815 1,027,413 989,704 954,389 1,364,948 1,348,325 1,315,277 1,299,591 5,328,141 C2050-LS-SR-SS-A1FI Low Impact 670,337 662,891 660,468 653,079 642,493 800,308 797,478 791,200 788,036 787,616 Moderate Impact 202,938 202,614 196,161 187,179 176,332 508,301 503,713 486,122 477,521 459,666 High Impact 52,012 43,112 35,525 27,430 21,047 66,193 57,813 46,058 37,853 31,149 Total 925,287 908,617 892,154 867,688 839,872 1,374,802 1,359,004 1,323,380 1,303,409 5,360,595 Source: Panya Consultants’ calculation L2.2 Affected Buildings For the C2050-LS-SR-SS-A1FI-T30 case, approximately 1.1 million buildings in Bangkok and Samut Prakarn might be affected. In the eastern area of the Chao Phraya River, such as Bang Kho Laem and Yan Nawa districts, 120,000 buildings are vulnerable. In the western areas, such as Bang Khun Thian, Bang Bon, Bang Khae, and Phra Samut Chedi districts, 300,000 buildings might be affected. In North Bangkok, 80,000 houses in Don Muang might be flooded. The comparisons of affected buildings in between C2008-T30 and C2050-LS-SR-SS-A1FI-T30 scenarios by district are shown inTable L2.2-1. Quantity of affected buildings and housing in Bangkok and Samut Prakarn is presented in Table L2.2-2. Damage costs related to depth of flood in various scenarios are shown in Table L2.2-3. L2.3 Losses of Income The commercial sector might lose the highest income due to flooding in the future. Losses of income in Bangkok and Samut Prakarn in various scenarios are shown in Table L2.3-1. Daily wage earner In this study, vulnerable daily wage earners are considered to be based in condensed communities. For case C2008-T30, the income loss of daily wage earners is 92 million baht whereas the income loss of daily wage earners is 140 million baht in case C2050-LS-SR-SS-A1FI-T30. Commerce and Industry For case C2008-T30, income losses of commerce and industry are 4 and 2.6 billion baht respectively, whereas they are 22 and 10 billion baht for case C2050-LS-SR-SS-A1FI-T30. L-12 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix L: Impact Assessment Table L2.2-1 Affected Buildings of Case C2008-T30 and C2050-LS-SR-SS-A1FI-T30 Unit: building C2008-T30 C2050-LS-SR-SS-A1FI-T30 Province/District Resident Commerce Industry Total Resident Commerce Industry Total Bangkok 273,765 44,194 7,945 325,903 793,375 202,986 26,039 1,022,400 District Bang Bon 23,185 4,078 1,563 28,826 60,133 16,760 4,406 81,299 Bang Kapi - - - - - - - - Bang Khae 14,985 1,860 552 17,397 43,604 9,281 1,000 53,885 Bang Khen 1,117 131 11 1,258 2,900 506 14 3,420 Bang Kho Laem 16,128 4,119 418 20,665 48,017 16,987 2,209 67,212 Bang Khun Thian 15,470 2,525 377 18,372 66,351 10,721 4,935 82,008 Bang Na 133 23 1 157 1,862 493 33 2,389 Bang Plat 5,007 2,695 83 7,784 30,909 11,272 585 42,766 Bang Rak 4,300 825 97 5,223 5,243 3,408 160 8,811 Bang Su 18,891 3,021 1,404 23,316 41,724 11,917 841 54,482 Bangkok Noi 1,791 293 11 2,094 12,161 3,520 164 15,844 Bangkok Yai 472 100 5 577 2,520 945 102 3,567 Bung Kum - - - - - - - - Chatuchak - - - - - - - - Chom Thong 5,879 934 186 6,999 14,195 4,332 803 19,330 Din Daeng - - - - - - - - Don Maung 33,172 3,196 335 36,703 77,937 11,524 182 89,643 Dusit 6,496 1,470 56 8,021 19,510 5,984 150 25,645 Huai Khwang - - - - - - - - Khanna Yao 480 53 7 540 482 109 5 596 Khlong Sam Wa 6,634 296 36 6,966 12,813 1,214 63 14,090 Khlong San 7,933 2,080 94 10,107 26,973 12,002 1,145 40,120 Khlong Toei - - - - 2,244 674 48 2,966 Lak Si 1,311 138 17 1,466 17,154 2,786 87 20,026 Lat Krabang 3,724 383 104 4,211 15,112 2,497 264 17,874 Lat Phrao - - - - - - - - Min Buri 8,468 932 160 9,560 14,370 2,893 189 17,453 Nong Chok 14,995 575 313 15,883 32,757 2,435 324 35,516 Nong Khaem 17,698 1,766 464 19,928 34,288 6,847 884 42,019 Pathum Wan - - - - - - - - Phasi Charoen 10,210 1,303 178 11,690 23,099 5,473 812 29,384 Phaya Thai - - - - - - - - Phra Kanong 838 87 18 943 4,990 892 102 5,985 Phra Nakhon 3,916 2,806 71 6,793 11,008 10,425 235 21,668 Pom Prap Sattruphai - - - - - - - - Prawet 1,982 228 30 2,240 4,165 806 80 5,051 Rat Burana 11,909 2,680 782 15,371 31,182 10,485 2,045 43,712 Rat Thewi - - - - - - - - Sa Thon 4,440 386 19 4,845 20,523 5,635 846 27,004 Sai Mai 796 1,026 64 1,886 22,337 4,209 73 26,619 Samphanthawong 11,524 588 87 12,199 11,266 2,732 196 14,194 Saphan Sung 376 99 6 482 313 143 2 458 Suan Luang - - - - - - - - Taling Chan - - - - 2,323 434 14 2,771 Thawi Watthana - - - - 896 143 4 1,043 Thon Buri 10,445 2,360 126 12,930 23,035 8,693 757 32,485 Thung Khu 6,948 612 132 7,691 15,761 2,287 655 18,702 Wang Thong Lang - - - - - - - - Watthana - - - - - - - - Yan Nawa 2,115 528 135 2,779 39,221 11,519 1,625 52,365 Samut Prakarn 38,986 3,086 539 42,611 129,789 11,191 2,607 143,588 Amphoe Bang Bo 5,261 476 36 5,774 12,121 828 84 13,033 Bang Phi 3 0 0 4 557 34 11 602 Muang Samut Prakarn 2,744 202 24 2,969 25,609 1,422 220 27,251 Phra Pradaeng 368 180 34 582 12,355 4,568 1,146 18,069 Phra Samut Chedi 30,092 2,182 433 32,707 78,087 4,270 1,123 83,479 Bang Sao Thong 518 45 12 575 1,060 69 25 1,154 Source: Panya Consultants’ calculation L-13 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix L: Impact Assessment Table L2.2-2 Affected Buildings and Housing in Different Cases Unit: building 30-Year Return Period Flood (T30) 100-Year Return Period Flood (T100) Building Bangkok Samut Prakarn BKK & SPK Bangkok Samut Prakarn BKK & SPK C2008 Residence 273,765 38,986 312,751 451,337 44,579 495,916 Commerce 44,194 3,086 47,280 74,173 4,894 79,067 Industry 7,945 539 8,484 12,196 870 13,066 Total 325,904 42,611 368,515 537,706 50,343 588,049 C2050-LS Residence 630,189 90,765 720,954 886,796 95,459 982,256 Commerce 160,898 5,605 166,503 224,822 8,180 233,002 Industry 21,816 1,307 23,123 25,125 1,917 27,042 Total 812,903 97,677 910,580 1,136,743 105,557 1,242,300 C2050-LS-SR-B1 Residence 753,894 111,883 865,777 1,049,491 124,551 1,174,042 Commerce 190,640 9,115 199,755 267,282 11,523 278,805 Industry 24,555 2,131 26,686 29,495 2,695 32,190 Total 969,089 123,129 1,092,218 1,346,268 138,768 1,485,037 C2050-LS-SR-A1FI Residence 778,064 121,277 899,341 1,073,925 132,916 1,206,842 Commerce 198,144 10,589 208,733 275,045 12,568 287,612 Industry 25,520 2,489 28,009 29,953 2,921 32,874 Total 1,001,728 134,355 1,136,083 1,378,923 148,405 1,527,328 C2050-LS-SR-SS-A1FI Residence 793,375 129,789 923,164 1,102,575 148,652 1,251,227 Commerce 202,986 11,191 214,177 283,119 13,674 296,793 Industry 26,039 2,607 28,646 30,809 3,140 33,949 Total 1,022,400 143,587 1,165,987 1,416,503 165,466 1,581,969 Source: Panya Consultants’ calculation Table L2.2-3 Damage Cost of Buildings and Housing in Different Cases Unit: million Baht Depth of Flood at T30 (cm) Depth of Flood at T1000 (cm) Building Total Total 10-50 50-100 100-200 >200 10-50 50-100 100-200 >200 C2008 Residence 5,426 6,204 2,895 1,370 15,894 4,477 15,802 9,970 3,308 33,557 Commerce 3,224 3,491 972 606 8,293 2,413 11,625 5,525 1,396 20,960 Industry 874 1,531 449 240 3,094 757 3,415 1,947 402 6,520 Total 9,524 11,226 4,315 2,216 27,282 7,647 30,842 17,442 5,106 61,037 C2050-LS Residence 11,752 16,204 5,925 3,859 37,739 8,600 29,299 26,527 3,993 68,420 Commerce 11,046 13,849 2,870 1,485 29,250 7,281 33,436 19,191 1,749 61,657 Industry 2,422 3,878 1,202 1,009 8,511 1,879 6,971 2,608 898 12,356 Total 25,220 33,930 9,997 6,353 75,500 17,761 69,706 48,326 6,640 142,433 C2050-LS-SR-B1 Residence 12,702 20,131 11,771 4,143 48,746 10,440 35,979 29,488 4,684 80,591 Commerce 11,831 18,775 6,522 1,562 38,689 8,290 41,590 22,445 1,868 74,194 Industry 2,671 4,875 1,776 1,003 10,326 2,017 8,639 3,867 1,060 15,582 Total 27,203 43,781 20,069 6,708 97,761 20,747 86,207 55,801 7,612 170,367 C2050-LS-SR-A1FI Residence 12,547 21,555 13,637 4,333 52,072 9,859 38,191 31,522 5,058 84,631 Commerce 11,699 20,808 8,029 1,621 42,157 7,841 44,175 24,446 2,030 78,492 Industry 2,650 5,489 2,153 1,054 11,346 1,843 9,311 4,270 1,148 16,572 Total 26,896 47,852 23,819 7,008 105,576 19,543 91,678 60,238 8,237 179,695 C2050-LS-SR-SS-A1FI Residence 11,528 25,161 13,462 5,281 55,432 9,586 41,017 31,924 6,101 88,628 Commerce 10,592 25,259 8,124 1,970 45,945 7,511 47,260 24,999 2,376 82,147 Industry 2,397 6,552 2,089 1,263 12,302 1,775 10,016 4,296 1,353 17,440 Total 24,518 56,972 23,675 8,514 113,679 18,873 98,293 61,220 9,829 188,215 Source: Panya Consultants’ calculation L-14 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix L: Impact Assessment Transportation The result finds operation losses for the expressway are zero as all expressway routes are above one meter of flood depth Water Supply and Sanitation System The water supply and sanitation system had a minimal impact. For case C2008-T30, income loss for the water supply and sanitation system is 6 million baht, whereas for case C2050-LS-SR-SS- A1FI-T30 it is 13 million baht. Energy For case C2008-T30, income loss for energy is 254 million baht whereas for case C2050-LS-SR-SS- A1FI-T30 it is 1.1 billion baht. L2.4 Affected Infrastructure The results of case C2050-LS-SR-SS-A1FI-T30 shows roughly 1,700 km of roads in Bangkok and Samut Prakarn would be vulnerable to flood over one meter. Lat Krabang water supply distribution station and Nongkhaem solid waste transfer station flooded with a depth of 50-100 cm. However, flooding cannot affect any water supply and sanitation system. For the energy infrastructure, no electrical substations are affected. L2.5 Affected Public Health Care System Under case C2008-T30, the health care cost is 934 million baht whereas for case C2050-LS-SR- SS-A1FI-T30 it is 2 billion baht. We predict 127 health care facilities flooded with a depth of 10- 200 cm, with most located in Bang Khun Thian, Bang Bon, Bang Khae and Phra Samut Chedi Districts. Table L2.3-1 Losses of Income Related to Duration of Flood Unit: million Baht Duration of Flood at T30 Duration of Flood at T100 Income Loss <1 day 1-7 day 7-15 day 15-30 day > 30 day <1 day 1-7 day 7-15 day 15-30 day > 30 day C2008 Daily Wage Earner 3.29 13.03 25.67 47.14 91.63 5.76 23.00 45.81 85.45 167.11 Commerce 146.57 580.01 1,144.14 2,095.86 4,077.04 317.51 1,264.05 2,516.68 4,685.75 9,172.01 Industry 97.69 383.68 751.85 1,368.39 2,640.33 173.64 685.89 1,358.92 2,514.41 4,896.61 WS & SS 0.29 1.17 2.14 3.47 5.27 0.32 1.26 2.31 3.79 5.72 Energy 15.00 56.98 100.84 154.01 253.91 29.61 114.82 213.84 366.14 658.88 C2050-LS Daily Wage Earner 3.68 14.64 28.81 52.71 101.99 6.14 24.44 48.57 90.34 176.26 Commerce 528.65 2,107.85 4,173.91 7,692.83 14,940.04 949.14 3,789.09 7,546.93 14,074.67 27,744.14 Industry 261.67 1,036.02 2,028.68 3,691.95 7,065.92 354.46 1,400.24 2,769.93 5,113.83 9,964.59 WS & SS 0.70 2.63 4.54 7.22 11.34 0.85 3.18 5.54 9.07 14.64 Energy 38.36 148.17 244.60 388.82 597.67 86.15 332.32 617.83 1,065.98 1,954.41 C2050-LS-SR-B1 Daily Wage Earner 4.44 17.63 34.97 64.68 127.72 7.15 28.32 56.25 104.83 206.10 Commerce 674.52 2,684.93 5,344.83 9,921.64 19,517.59 1,161.22 4,613.18 9,183.68 17,146.40 33,963.22 Industry 316.39 1,246.06 2,447.81 4,481.33 8,595.62 437.88 1,702.79 3,355.45 6,209.63 12,173.70 WS & SS 0.75 2.78 4.89 7.76 12.11 0.94 3.55 6.16 10.13 16.78 Energy 53.02 203.05 365.68 593.71 1,057.01 108.94 424.98 794.91 1,394.82 2,525.02 C2050-LS-SR-A1FI Daily Wage Earner 4.82 19.12 37.85 69.98 137.24 7.06 28.03 55.57 103.49 204.58 Commerce 721.71 2,866.85 5,719.12 10,615.05 20,883.45 1,186.04 4,717.13 9,369.20 17,479.11 34,614.87 Industry 344.30 1,337.05 2,634.31 4,832.35 9,396.92 458.22 1,794.56 3,511.30 6,472.64 12,692.16 WS & SS 0.80 2.86 5.07 7.91 12.22 0.99 3.65 6.39 10.33 16.93 Energy 59.19 226.07 410.99 663.74 1,104.25 101.85 391.92 729.30 1,278.23 2,339.24 C2050-LS-SR-SS-A1FI Daily Wage Earner 4.93 19.52 38.65 71.26 139.69 7.11 28.21 55.92 103.94 205.31 Commerce 760.58 3,009.96 6,028.50 11,076.85 21,671.38 1,232.33 4,907.19 9,741.20 18,132.23 35,908.13 Industry 360.16 1,392.40 2,756.29 5,018.98 9,725.60 476.99 1,870.61 3,659.38 6,720.13 13,157.60 WS & SS 0.82 2.81 4.99 7.86 12.56 1.00 3.59 6.34 10.21 16.95 Energy 59.83 226.33 406.87 668.68 1,144.84 102.57 395.96 728.77 1,271.19 2,340.55 Remark: WS & SS = Water Supply and Sanitation System Source: Panya Consultants’ calculation L-15 APPENDIX M ADAPTATION AND PROPOSAL Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal APPENDIX M ADAPTATION AND PROPOSAL M1 GENERAL Climate change impacts on Bangkok and vicinities are manifested through a higher risk of flooding and consequent effects on economic and social resilience of the area. Flooding is not uncommon in this area and was responsible for severe socio-economic losses in the past. Inhabitants of the area have been adapting to flooding for decades and strategies for managing flood risks have evolved through time. Nevertheless, additional adaptation measures will be required to reduce the adverse impacts of projected climate change and variability. Moreover, vulnerability to climate change can be exacerbated by other stresses. These arise from, for example, current climate hazards, poverty and unequal access to resources, food insecurity, trends in economic globalization, conflict, and incidence of diseases. It is difficult to separate adaptations made in response to climate induced flood pressures from actions taken in response to other forces emanating from demographic, social, economic, technological, environmental, and other changes. In this Chapter, a brief on adaptation options discussed by a number of stakeholders, as well as those adopted by a peer Asian city is reviewed. Additionally, adaptation options proposed earlier to address flooding in the Chao Phraya River Basin are also enumerated. The intension is to lay out an array of options that can be implemented. Emphasis is given to stakeholder experiences with measures to manage flooding and their perspectives on the potential for applying the same measures to adapt to climate change. Finally, the proposed adaptation options are deconstructed. This will pave the way to embed the proposed adaptation within broad initiatives. M2 REVIEW OF ADAPTIVE PRACTICES A wealth of well-tested experience, information and technology is already available to identify viable adaptation strategies. The Consultant reviewed and analyzed some of the more prominent practices and potential adaptive interventions, such as, among others, improving flood forecasting and preparing strategies for flood warnings, evacuation, transport during floods, and post-flood recovery; implementing protection (e.g. construction of dikes/seawalls) or retreat strategies for coastal development; changes in coastal development and land use; public information campaigns and training exercises. Key options are briefed as follows: Be prepared: improving flood forecasting and preparing strategies for flood warnings and evacuation plans during floods and post-flood recovery. 1) Public information campaigns and training exercises; 2) Involving communities in making decisions on flood risk mitigation planning; 3) Anticipating climate change in city planning, pursuing risk-based decision making; and 4) Enhancing institutional capacity for decision-making, and raising public awareness. Slow the flood: Strategies to reduce the speed and size of floods include moving embankments back from rivers and restoring wetlands, floodplains and meanders, and slowing down urban runoff. These measures also have major ecological, aesthetic, and recreational benefits. Slowing the flood also seeks to divert as much water as possible away from developed areas and to improve drainage in flood-prone areas; partly as a flood prevention measure and partly to reduce the amount of time that buildings are inundated when floods do occur. Measures for such flood slowing include: 1) Moving levees back from rivers: set-back levees; 2) Restoring meanders; 3) Letting floodplain wetlands play their natural role of providing flood storage; and M-1 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal 4) Creating flood detention basins alongside rivers. De-paving cities: Numerous techniques are available to limit the volume and speed of urban flooding. 1) New permeable materials which can be used on roads, car parks and playgrounds; 2) Strips of shrubs and trees alongside streets and sidewalks; 3) Grassed depressions (swales) which catch flood and allow it to infiltrate into the ground; and 4) In many USA cities: convert their downspouts so that they discharge water over lawns or other non-paved areas rather than down sewers, or collect the runoff in rain barrels. These techniques not only reduce flood risks but also replenish groundwater and reduce pollution into rivers and bays from urban flooding. Improve emergency procedures: Possibly the most important measures in terms of saving lives are to improve flood forecasting, warning, and evacuation procedures. It is also vital to prepare strategies in advance to help households and communities recover from the impacts of floods. Insurance programs, for example, may be designed to pay only those inhabitants who contribute to improving ecological goods and services. Move out of harm’s way: A vital part of reducing damage, especially in less densely populated areas, is to discourage people from living in the areas most vulnerable to floods. Floodplain management includes planning regulations to discourage new floodplain development, and financial incentives for people living in the riskiest areas to move to higher ground. 1) Planning control to dissuade people from living in the most vulnerable parts of floodplains; 2) Well maintained and strengthened embankments; 3) Stilts or small mounds for isolated buildings; and 4) Buildings surrounded by small ring-dykes, and these can serve as a place of refuge and storage. Protect the most vulnerable buildings and areas: Flood risk management includes structural measures such as flood-proofing of individual buildings (for example, by raising them on stilts or mounds) and communities (e.g., building flood shelters and flood-protected water sources), the building of floodplain storage and bypass systems (areas of sparsely or undeveloped land which can be used to divert or store high floods), and the judicious use of well-maintained embankments for vulnerable urban areas. Improve dam management: In many countries, dams worsen flood damages when they overtop, collapse or are poorly operated (as when reservoirs are kept full in order to maximize power generation, leaving little room for flood storage). Operating rules for dams should be developed with opportunity for public input which are published and stringently enforced. A safety assessment of existing dams is another critical issue; plans for removing unsafe dams should be prioritized. A better way: Emphasizing flood management based on public participation and recognition of the environmental benefits of “normal” flooding supersedes flood control. The preferred solution is now the restoration of natural processes, and especially opportunities to create more space for the river. This means that the floodplains should only be used for necessary river-related activities, while measures should be taken to give the river more room to expand as in Netherlands. For New Orleans case, working with the forces of nature rather than against them implies building over a period of decades a new port and city of New Orleans on higher ground near the mouth of M-2 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal the Atchafalaya. The natural process of sediment deposition around the “lobe” where the Atchafalaya meets the Gulf would be encouraged, offering protection against subsidence and storm surges. The Study on Integrated Plan for Flood Mitigation in Chao Phraya River Basin (RID, 1999): The study proposed the following structural and non-structural measures: Structural measures: 1) River improvement: The study acknowledged that despite a number of limitations, river improvement is still one of the essential measures to mitigate flood damage. However, the study proposed further study before adopting the measure; 2) Flood diversion canal: This is one of the applicable structural measures, so further study on the combination with other measures as well as the optimization of route and scale is proposed; 3) Tidal barrage with pump: This measure is not possible for the economic and technical point of view; and 4) Retarding basin: Retarding basins are identified as a basic component of flood mitigation. Non-structural measures: 1) Modification of reservoir operation rule: Setup of the rule curve, reduction of water supply and hydropower generation is regarded as the costs for modification; 2) Strengthening of control and guidance: Land use control and guidance on land development to maintain the present water level and control of excessive groundwater extraction; 3) Flood disaster response: Improvement of flood forecasting and warning system to decentralize the responsibility for flood fighting and to involve local people more; 4) Financial response: Subsidy for flood damage especially to farmer and flood insurance for agriculture; 5) Watershed management: Prevent the deforestation in order to decrease flood peak and to increase the recharging capacity; and 6) Institution and organization: Coordination of agencies responsible is necessary and the Water Resources Act for comprehensive flood control is introduced. M3 ADAPTATION OPTIONS AND PROPOSAL The adaptation options are intimately connected to its social and economic development. At the same time, they are dynamic and influenced by the productive base including natural and man- made capital assets, social networks and entitlements, human capital and institutions, governance, national income, health, and technology. Nevertheless, available options vary unevenly across and within societies. A range of barriers limit both the implementation and effectiveness of adaptive measures. The capacity to adapt is even societies with high adaptive capacity remain vulnerable to climate change, variability, and extremes. To cope with the recurring flooding in Bangkok, the agencies responsible for flood mitigation and drainage works have prepared a number of plans. These plans, in general, consist of structural and non-structural measures. However, in formulating these plans, climate change impact on hydrology was not considered. The results of simulation study revealed that the existing and planned flood protection system would be inadequate to cope with the impacts of flooding greater than a 10-year return period in 2050 and corresponding to the A1FI climate change scenario. Therefore, to cope with the climate change on hydrology in 2050, the adaptation measures were studied and proposed. M-3 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal M3.1 Structural Measures In general, the structural measures types carried out by the concerned agencies to cope with flooding are summarized as follows: 1) Polder system together with the improvement of drainage system including drainage canal, regulator, and pump facilities; 2) Dikes along the river courses; 3) Water conservation areas (Monkey Cheek); 4) Large storage dam in the upper basin; 5) Barrage at the river mouth; 6) Diversion channel; and 7) Coastal erosion protection. Polder, Dike, and Monkey Cheek A polder with drainage system improvement covering the Bangkok metropolitan area has been developed and dike construction has progressed continuously along the Chao Phraya River even in rural areas. Moreover, several water conservation or retaining areas (named the Monkey Cheek by His Majesty King Bhumibol) in the western and eastern areas of the Chao Phraya River have been developed. While most of these structural measures are already in place, some are scheduled to be completed in 2011. All existing and on-going measures were included in the study. Large Storage Dam in the Upper Basin A large storage dam in the upper basin has been proposed in the past to save Bangkok from flooding. For example, the Kaeng Sua Ten Dam has been proposed and studied several times whenever severe flood damage occurred in the Yom River Basin. Unfortunately, building new dams can be controversial due to their potential social and environmental impact, and therefore are not pursued as good options for flood control. Barrage at the River Mouth A tidal barrage at the mouth of the Chao Phraya River has been proposed and its effectiveness was examined in a previous study (RID, 1999). The barrage and pumps were found to be effective in lowering the floodwater in Bangkok but are not effective in controlling large flood discharge. Furthermore, this measure requires a huge investment cost (131 billion baht in 1998 prices), involves social and environmental problems, and may interfere with navigation. As such, barrage is not considered a suitable option in the long term. Diversion Channel A flood diversion channel from Ayutthaya to the river mouth (the Chao Phraya River II project) was proposed to mitigate flood damage (RID, 1999). Alternative routes were studied. However, due to a complicated land acquisition process and high investment cost (42 billion baht in 1998 for a capacity of 1,100 m3/sec) the proposal was not pursued. In 2006, the RID proposed improvement of existing irrigation canals to divert water and increasing the pumping capacity on the right bank of the Bang Pakong River and on the coast of the Gulf of Thailand (RID, 2006). The latter proposal by the RID was included in the current adaptation plan. Coastal Erosion and Wave Protection The BMA has a plan to construct 10 T-groins along the 4.7-km shoreline at Bang Khun Thian district to protect against coastal erosion (BMA, 2007a). Apart from the T-groins, the BMA will grow mangrove trees to protect the shoreline. At present, more than 760 m of the Bang Khun Thian shoreline has eroded, resulting in a decrease in forest density. The Department of Marine and Coastal Resources (DMCR) has been studying a Master Plan and Practice to Solve the Problem of Coastal Erosion on the Shoreline along the Upper Gulf of Thailand. The plan will propose a suitable solution to protect the shoreline. At present, local M-4 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal people construct bamboo barriers to weaken the strength of the waves hitting the coast to prevent coastal erosion. In addition, the bamboo barriers help to raise silt deposition on the coast. Proposed Structural Measures The results of the simulation study indicate that the crest elevations of dikes around Bangkok and vicinities and along both banks of the Chao Phraya River will not be high enough to cope with the flooding of more than a 10-year return period in the future. Moreover, the protected area in the west of the Chao Phraya River has insufficient pump capacity to drain the floodwater into the Tha Chin River and the Gulf of Thailand. Thus, dike and pumping capacity improvement are proposed. Since the area along the shoreline in Samut Prakarn on the east of the Chao Phraya River is an industrial community, the shoreline has been protected from erosion by rock-pile embankment constructed by the Department of Public Works and Town & Country Planning (DPT) incorporation with the province. On the contrary, the area along the shoreline on the west of the Chao Phraya River has been eroded about 5 to 10 m per year. Over the last 30 years, erosion and land subsidence in this area has caused the village’s shoreline to diminish by more than 1 km. The appropriate solution to solve this problem has to be studied and proposed urgently. For the eastern part of Bangkok, pumping capacity to drain floodwater into the Bang Pakong River and the Gulf of Thailand should be increased from 737 to 1,065 m3/sec. The total capacity of canals should be improved from 607 to 1,580 m3/sec. For the western part of Bangkok, there are three major pumping stations at Khlong Phasi Charoeng, Sanam Chai, and Khun Rat Phinit Chai to drain the floodwater into the Tha Chin River and the Gulf of Thailand with capacities of 18, 36, and 30 m3/sec respectively (totally 84 m3/sec). The current capacity is inadequate to cope with future climate change. Based on the simulation results, the following improvement of pumping capacities and canal improvement is proposed (Table M3.1-1). Table M3.1-1 Proposed Pumping Capacities in the Western Area of Bangkok Unit: m3/sec Pumping Station Existing* 30-Year Return Period 100-Year Return Period 1. Phasi Charoeng 18 400 550 2. Sanam Chai 36 200 350 3. Khun Rat Phinit Chai 30 100 250 Total 84 700 1,150 Source: * from RID’s Office Region 11 and BMA and proposed by the Consultant Figure M3.1-1 compares maximum inundation area corresponding to a 30-year return period flood with and without the proposed structural adaptation measures. It is observed that the maximum inundation area of Bangkok and Samut Prakarn will reduce with adaptation measures from 744.34 to 362.14 km2, a decrease of 382 km2 or 51%. In this study, the cost of structural measures of dikes, pumps, and drainage canal improvement together with the coastal erosion protection were preliminarily estimated. These structural measures are considered as an appropriate solution to cope with climate change on hydrology in 2050. However, they should be studied carefully in more details especially updating data in the feasibility studies as soon as possible. M-5 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal 620000 640000 660000 680000 700000 620000 640000 660000 680000 700000 1580000 1580000 1580000 1580000 1560000 1560000 1560000 1560000 Pathum Thani Pathum Thani ! ( ( ! 1540000 1540000 1540000 1540000 Nonthaburi Nonthaburi ( ! ! ( Nakhon Pathom Nakhon Pathom ( ! ! ( Bangkok Bangkok ( ! ! ( 1520000 1520000 1520000 1520000 Samut Prakan Samut Prakan ( ! ( ! 1500000 1500000 1500000 1500000 Samut Sakhon Samut Sakhon ! ( ( ! 1480000 1480000 1480000 1480000 620000 640000 660000 680000 700000 620000 640000 660000 680000 700000 Legend ! ( Province Province Boundary -3 - -1 -1 - 0 5-8 8 - 10 0 - 10 10 - 50 Ê 0 2 4 8 12 16 Legend ( ! Province Province Boundary -3 - -1 -1 - 0 5-8 8 - 10 0 - 10 10 - 50 Ê 0 2 4 8 12 16 Dike 0-1 10 - 15 50 - 100 Kilometers Kilometers Dike 0-1 10 - 15 50 - 100 River/Canal Network 1-2 15 - 20 100 - 200 Max. Water Depth River/Canal Network 1-2 15 - 20 100 - 200 Max. Water Depth Elevation (m.MSL) 2-3 20 - 25 200 - 300 3-4 > 25 300 - 400 C2050-LS-SR-SS Elevation (m.MSL) 2-3 20 - 25 200 - 300 C2050-LS-SR-SS -7 - -5 -7 - -5 3-4 > 25 300 - 400 -5 - -3 4-5 Max.Water Depth (cm) > 400 -A1FI-T30 -5 - -3 4-5 Max.Water Depth (cm) > 400 -A1FI-T30Adap Source: Panya Consultants’ calculation Figure M3.1-1 Maximum Inundation Area in Case of With and Without the Proposed Adaptation M3.2 Preliminary Cost Estimate Dikes As discussed in the previous section, the existing crest elevations of dikes will not be high enough to protect against flooding at a return period of higher than 10 years in the future (2050) under the A1FI climate change scenario (including land subsidence, sea level rise, and storm surge). To cope with future floods at a 30- or 100-year return period, the dike crest elevations have to be raised. Table M3.2-1 The dike routes around the protected area and their length in the eastern area of the Chao Phraya River were delineated on a 1:50,000 scale map. The dike crest elevations at present were estimated from the collected information from the BMA and the RID together with a site visit. The dike crest elevations in the future were estimated by taking into account land subsidence of 0.20 m and free board of 0.30 m. Table M3.2-2 depicts the same way but of the western area of the Chao Phraya River. The northern dike along Khlong Maha Sawat has an alternative to use railway from Khlong Bangkok Noi to Road No.3316. The southern dike has an alternative to extend the flood protection area to Khlong Sanphasamit. These alternatives should be studied in the next stage. The maximum flood water levels are derived from the results of simulation study. The dikes along the Chao Phraya River are mostly concrete retaining wall or raised elevations of roads. Four types of dike improvement method and their unit costs were derived from the study results of drainage system improvement in the western area of Bangkok (BMA, 2005a) as shown in Figure M3.2-1 and Table M3.2-3. The unit costs were adjusted to 2008 prices by applying the annual inflation rate obtained from the NESDB. M-6 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal Source: BMA, 2005 Figure M3.2-1 Dike Improvement Pumps Results from the simulation study reveal that in the future the pumping system in the eastern area of the Chao Phraya River will have enough capacity to cope with repeated flooding. On the other hand, the pumping system in the western area of the Chao Phraya River will not have enough capacity. The pumping stations at Phasi Charoen and Sanam Chai should be upgraded to capacities of 400 and 200 m3/sec for floods of a 30-year return period (550 and 350 m3/sec for floods at a 100-year return period) respectively. These two pumping stations will drain the flood water inside the protection area into the Tha Chin River. The pumping station at Klong Khun Rat Phinit Chai should also add capacity to reach 100 and 250 m3/sec for floods at a 30-and 100-year return period respectively. However, drainage canals to convey the flood water from the inundated area to the pumping stations have to be trained. The unit costs of pumping station and drainage canal improvement were derived from the study results of the drainage system improvement in the area around Suvarnabhumi Airport (RID, 2004) as also shown in Table M3.2-3. Coastal Erosion Protection A number of agencies proposed and compared methods of coastal erosion protection in the past. However, their effectiveness and environmental impact are yet to be thoroughly scrutinized. The BMA (2007a) proposed coastal erosion protection including the rehabilitation of mangrove forest long the shoreline of Bang Khun Thian as shown in Table M3.2-3. In the eastern area of the Chao Phraya River, there are plans to construct rock-pile embankments along the shoreline to protect the industrial community area from coastal erosion and waves. However, the embankment crest elevations will not be high enough. Thus, they will be improved by raising the crest along all the length of the embankments. M-7 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Table M3.2-1 Designed Dike Crest Elevations in the Eastern Area of the Chao Phraya River 30-year Return Period Flood 100-year Return Period Flood Location Description Distance Crest EL Max. Designed Crest EL Additional Max. Designed Crest EL Additional Present Future* Water EL Future** Present*** Height Water EL Future** Present*** Height (km) (m.MSL) (m.MSL) (m.MSL) (m.MSL) (m.MSL) (m) (m.MSL) (m.MSL) (m.MSL) (m) Western Dike 1 Dike along Left Bank of Chao Phraya River from Ban Pho Thong Bon to RID Pak Kret 9.50 3.00 2.80 3.80 4.10 4.30 1.30 4.70 5.00 5.20 2.20 2 Dike along Left Bank of Chao Phraya River from RID Pak Kret to Rama VII Bridge 11.00 3.00 2.80 3.47 3.77 3.97 0.97 4.14 4.44 4.64 1.64 3 Dike along Left Bank of Chao Phraya River from Rama VII Bridge to Memorial Bridge 7.00 3.00 2.80 3.36 3.66 3.86 0.86 3.95 4.25 4.45 1.45 4 Dike along Left Bank of Chao Phraya River from Memorial Bridge to Taksin Bridge 9.00 3.00 2.80 3.22 3.52 3.72 0.72 3.71 4.01 4.21 1.21 5 Dike along Left Bank of Chao Phraya River from Taksin Bridge to Wat Yothin Pradit 21.75 2.80 2.60 2.87 3.17 3.37 0.57 3.12 3.42 3.62 0.82 Total 58.25 Northern Dike 1 Local Road from Ban Pho Thong Bon to Road No.306 0.75 2.00 1.80 2.69 2.99 3.19 1.19 2.95 3.25 3.45 1.45 2 Road No.306 from Ban Pho Thong Bon to Khlong Rangsit Prayunrasake 1.75 2.00 1.80 2.69 2.99 3.19 1.19 2.95 3.25 3.45 1.45 3 Local Road along Khlong Rangsit Prayunrasak to Road No.1 7.25 2.00 1.80 2.65 2.95 3.15 1.15 2.94 3.24 3.44 1.44 4 Road No.1 from from Khlong Rangsit Prayunrasak to Soi Phahon Yothin 58 5.25 2.00 1.80 2.65 2.95 3.15 1.15 2.94 3.24 3.44 1.44 5 Soi Phahon Yothin 58 to Khlong Hok Wa Sai Lang 1.50 2.00 1.80 2.43 2.73 2.93 0.93 2.82 3.12 3.32 1.32 M-8 6 Local Road along Khlong Hok Wa Sai Lang to Khlong 14 31.25 2.00 1.80 2.43 2.73 2.93 0.93 2.82 3.12 3.32 1.32 Total 47.75 Eastern Dike 1 Local Road along Khlong 14 to Road No.3481 12.00 2.00 1.80 2.30 2.60 2.80 0.80 2.60 2.90 3.10 1.10 2 Road No.3481 from Ban Surao Mai to Khet Nong Chok 4.00 2.00 1.80 1.98 2.28 2.48 0.48 2.28 2.58 2.78 0.78 3 Road No.3481 from Khet Nong Chok to Khlong Phraongchao Chaiyanuchit 12.00 2.00 1.80 1.98 2.28 2.48 0.48 2.28 2.58 2.78 0.78 4 Local Road along Khlong Phraongchao Chaiyanuchit to Road No.7 18.25 2.00 1.80 1.84 2.14 2.34 0.34 2.15 2.45 2.65 0.65 5 Local Road along Khlong Phraongchao Chaiyanuchit to Road No.34 8.00 2.00 1.80 0.47 0.77 0.97 0.00 0.59 0.89 1.09 0.00 6 Local Road from Road No.34 to Chonrahan Phichit Pumping Station and to Road No.3 11.00 2.00 1.80 0.41 0.71 0.91 0.00 0.46 0.76 0.96 0.00 Total 65.25 Appendix M: Adaptation and Proposal Southern Dike 1 Road No.3 from Chonrahan Phichit Pumping Station to Chao Phraya River at Wat Yothin Pradit 39.50 2.00 1.80 0.46 0.76 0.96 0.00 0.58 0.88 1.08 0.00 2 Road No.3 from Chonrahan Phichit Pumping Station to Bang Pakong River at Amphoe Bang Pakong 24.00 2.00 1.80 0.46 0.76 0.96 0.00 0.58 0.88 1.08 0.00 Total 63.50 Erosion and Wave 1 Along the coast from the Chao Phraya River Mouth to Khlong Tomru 9.00 2.70 2.50 3.08 3.38 3.58 0.88 3.08 3.38 3.58 0.88 Wave Protection 2 Along the coast from Khlong Tomru to the Bang Pakong River Mouth 34.00 2.00 1.80 3.08 3.38 3.58 1.58 3.08 3.38 3.58 1.58 Total 43.00 Final Report Remark: *Crest dike elevation will be decreased by land subsidence about 0.20 m ** Designed dike crest elevation by adding 0.30 m of free board *** Designed dike crest elevation at present by adding 0.20 m for land subsidence Source: Panya Consultants Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Table M3.2-2 Designed Dike Crest Elevations in the Western Area of the Chao Phraya River 30-year Return Period Flood 100-year Return Period Flood Location Description Distance Crest EL Max. Designed Crest EL Additional Max. Designed Crest EL Additional Present Future* Water EL Future** Present*** Height Water EL Future** Present*** Height (km) (m.MSL) (m.MSL) (m.MSL) (m.MSL) (m.MSL) (m) (m.MSL) (m.MSL) (m.MSL) (m) Northern Dike 1 Suanphak Road from Khlong Bangkok Noi to Buddha Monthol Soi 2 Road 8.50 2.80 2.60 2.30 2.60 2.80 0.00 2.44 2.74 2.94 0.14 2 Buddha Monthol Soi 2 Road to Thammasop Road 1.50 2.80 2.60 2.30 2.60 2.80 0.00 2.44 2.74 2.94 0.14 3 Thammasop Road to Road No.3316 21.25 2.80 2.60 2.30 2.60 2.80 0.00 2.44 2.74 2.94 0.14 Total 31.25 Alternative 1 Railway from Khlong Bangkok Noi to Road No.3316 29.80 2.80 2.60 2.30 2.60 2.80 0.00 2.44 2.74 2.94 0.14 Western Dike 1 Road No.3316 from Ban Tha Talat to Road No.4 20.00 2.80 2.60 2.30 2.60 2.80 0.00 2.44 2.74 2.94 0.14 2 Road No.4 from Ban Suan Som to Ban Rong Hip Phatthana 3.50 2.80 2.60 2.14 2.44 2.64 0.00 2.23 2.53 2.73 0.00 3 Local Road from Road No.4 to Road No.3091 6.00 2.80 2.60 2.10 2.40 2.60 0.00 2.18 2.48 2.68 0.00 4 Road No.3091 to Ban Khlong Khae 2.00 2.80 2.60 2.09 2.39 2.59 0.00 2.16 2.46 2.66 0.00 5 Local Road from Road No.3091 to Amphoe Krathum Baen 5.50 2.80 2.60 2.05 2.35 2.55 0.00 2.11 2.41 2.61 0.00 6 Local Road from Amphoe Krathum Baen to Road No.3091 14.00 2.00 1.80 1.96 2.26 2.46 0.46 1.99 2.29 2.49 0.49 7 Road No.3091 from Ruang Napha Village to Road No.35 4.00 2.00 1.80 1.93 2.23 2.43 0.43 1.96 2.26 2.46 0.46 8 Road No.35 from Maha Chai Hospital to Ban Khlong Khru 0.75 2.00 1.80 1.92 2.22 2.42 0.42 1.95 2.25 2.45 0.45 M-9 9 Local Road from Road No.35 to Wat Sopana Ram 5.50 2.00 1.80 1.89 2.19 2.39 0.39 1.90 2.20 2.40 0.40 10 Local Road from Road No.35 to Khlong Sao Thong 2.50 2.00 1.80 1.87 2.17 2.37 0.37 1.88 2.18 2.38 0.38 Total 63.75 Southern Dike 1 Local Road from Khlong Sao Thong-Ban Khom-Ban Sandap-Ban Khok-Ban Ko Pho to Khlong Khun Rat Phinit Chai 20.00 2.00 1.80 2.63 2.93 3.13 1.13 2.68 2.98 3.18 1.18 2 Local Road from Khlong Khun Rat Phinit Chai-Ban Khlong Suan-Ban Khlong Kra Om-Ban Wat Yai Si-Ban Khu Sang Khu Som 17.50 2.00 1.80 2.63 2.93 3.13 1.13 2.68 2.98 3.18 1.18 -Ban Santisuk-Ban Sam Ruean to Road No.303 Total 37.50 Alternative 1 Local Road from Khlong Sao Thong to Khlong Phitthaya Longkon 3.00 2.00 1.80 2.63 2.93 3.13 1.13 2.68 2.98 3.18 1.18 2 Local Roand along Khlong Phitthaya Longkon to Khlong Khun Rat Phinit Chai 14.00 2.00 1.80 2.63 2.93 3.13 1.13 2.68 2.98 3.18 1.18 3 Local Road along Khlong Sanphasamit to Road No.303 14.50 2.00 1.80 2.63 2.93 3.13 1.13 2.68 2.98 3.18 1.18 Appendix M: Adaptation and Proposal 4 Road No.303 from Amphoe Phra Samut Chedi to Bangkok Phrapra Daeng Hospital 6.50 2.00 1.80 2.63 2.93 3.13 1.13 2.68 2.98 3.18 1.18 Total 38.00 Eastern Dike 1 Dike along Right Bank of Khlong Bangkok Noi from Wat Kai Tia to Chao Phraya River at Bangkok Noi Railway Station 4.50 2.80 2.60 2.89 3.19 3.39 0.59 3.16 3.46 3.66 0.86 2 Dike along Right Bank of Chao Phraya River to Wat Bang Peung 14.50 2.80 2.60 2.89 3.19 3.39 0.59 3.16 3.46 3.66 0.86 3 Local Road from Wat Bang Peung to Road No.303 1.50 2.80 2.60 2.87 3.17 3.37 0.57 3.12 3.42 3.62 0.82 4 Road No.303 from Wat Bang Peung to Bangkok Phrapra Daeng Hospital 7.25 2.80 2.60 2.56 2.86 3.06 0.26 2.77 3.07 3.27 0.47 Total 27.75 Erosion and Wave Along the coast from the Chao Phraya River Mouth to the Tha Chin River Mouth 35.75 3.08 3.38 3.58 3.08 3.38 3.58 Final Report Wave Protection Remark: *Crest dike elevation will be decreased by land subsidence about 0.20 m ** Designed dike crest elevation by adding 0.30 m of free board *** Designed dike crest elevation at present by adding 0.20 m for land subsidence Source: Panya Consultants Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Table M3.2-3 Unit Costs of Dike, Pump and Canal Improvement, and Coastal Erosion Protection Raising Unit Cost Estimated Cost Type Description Height Year 2005* Year 2008** Type Description Year 2004* Year 2008** (m) (Baht/m) (Baht/m) (Million Baht) (Million Baht) 3 1 Raising Alphalt Concrete Road 1.00 8,600 9,956 100 m /sec 1. Construction of Pumping Station (Civil Work) 275.00 327.17 0.75 6,243 7,228 2. Pump and Appurtenance Structures (Electro-Mechanical Work) 1,788.50 2,127.78 0.50 4,141 4,794 3. Engineering and Administration @ 3.5% 72.22 85.92 0.25 2,500 2,894 Total 2,135.72 2,540.87 3 2 Retaining Wall 2.25 160,268 185,542 100 m /sec Canal Improvement 5,521 6,568 2.00 142,460 164,926 Remark: ** Applying Factor of 1.1897 from the inflation rates of 2.768 (2004), 4.542 (2005), 4.642 (2006), 2.229 (2007), and 1.75 124,653 144,310 3.522 (2008) obtained from NESDB 1.50 106,845 123,694 Source: * The Feasibility Study on Drainage System in the Area around Suvarnabhumi Airport, RID 2004 1.25 89,038 103,079 M-10 1.00 71,230 82,463 Unit Cost 3 Raising Crest of Dike by Retaining Wall 1.00 1,395 1,615 Type Description Year 2007* Year 2008** 0.75 1,046 1,211 (Baht/m) (Baht/m) 0.50 698 807 5 Coastal Erosion and Wave Protection 82,734 87,557 0.25 349 404 Remark: ** Applying Factor of 1.0583 from the inflation rates of 2.229 (2007) and 3.522 (2008) obtained from NESDB 4 Raising Crest of Retaining Wall 0.50 323 374 Source: * The Study on Coastal Erosion Protection along the Shoreline of Bang Khun Thian, BMA 2007 0.25 162 187 Appendix M: Adaptation and Proposal Remark: ** Applying Factor of 1.1577 from the Inflation rates of 4.542 (2005), 4.642 (2006), 2.229 (2007), and 3.522 (2008) obtained from NESDB Estimated by Panya Consultants Source: * The Study, Survey, Design, and Master Plan of Drainage System in the areas of Khet Bangkok Noi, Bangkok Yai, Thon Buri, Rat Burana, Thung Kru, and Bang Khun Thian, BMA 2005 Final Report Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal Table M3.2-4 and Table M3.2-5 show the details of cost estimate of flood protection system and coastal erosion improvement in the eastern and western areas of the Chao Phraya River respectively. The total estimated costs are 35.2 and 49.4 billion baht to protect the flood at 30-or 100-year return period respectively. M3.3 Preliminary Economic Evaluation The preliminary economic evaluation of the proposed flood protection improvement project is carried out by comparing the cost and benefits with and without the project in order to identify the incremental benefit of the project. The viability of the project is determined by the economic indicators, i.e., Net Present value (NPV), Economic Internal Rate of Return (EIRR) and Benefit Cost Ratio (B/C). In the analysis the discounted rates of 8%, 10%, and 12% will be used. The analysis period used is 38 years, of which the first 8 years are for studying, designing and construction and 30 years is the economic benefit period of the project. Project cost: The project cost including the investment cost on flood protection infrastructure in both eastern and western area of the Chao Phraya River. Detail of cost estimate of these infrastructures of both areas is shown in Table M3.2-4 and Table M3.2-5. Detailed design cost is estimated at 0.3% of the project cost. The economic investment cost of the project is classified into three categories - civil work, pump, and design cost. Table M3.3-1 represents the disbursement of the investment cost of the project for both the flood of 30 and 100 year return period. Table M3.3-1 Investment Cost of Flood Protection Improvement Project Unit: million Baht Investment Cost for 30-yr. Return Period Investment Cost for 100-yr. Return Period Year Civil Civil FS & DD Pump Total FS & DD Pump Total Work Work 1 21 21 30 30 2 42 42 59 59 3 42 42 59 59 4 1,981 1,981 2,405 2,405 5 3,962 3,962 4,811 4,811 6 5,944 3,083 9,027 7,216 5,065 12,281 7 5,944 6,166 12,110 7,216 10,130 17,347 8 1,981 6,166 8,148 2,405 10,130 12,536 38 Total 106 19,812 15,416 35,334 148 24,054 25,326 49,528 Source: Panya Consultants’ calculation The annual operation and maintenance cost is estimated at 1% of the civil work and 2.5% of the pump work. The total annual operation and maintenance cost for the case of 30 and 100 year flood is estimated at 584 and 874 million baht respectively. Project benefit: The expected benefit of the project is the annual reduction of flood damage cost. In estimating annual benefit, the damage cost at each return flood period from the result of flood damage assessment is used. Figure M3.3-1 and M3.3-2 show the flood damage cost for different flood return period for with and without the project in case of the 30 and 100 year return period projects. M-11 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Table M3.2-4 Cost Estimate of Flood Protection Improvement in the Eastern Area of the Chao Phraya River 30-year Return Period Flood 100-year Return Period Flood Location Description Distance Additional Unit Amount Additional Unit Amount Height Type Cost Height Type Cost (km) (m) (Baht/m) (Million Baht) (m) (Baht/m) (Million Baht) Western Dike 1 Dike along Left Bank of Chao Phraya River from Ban Pho Thong Bon to RID Pak Kret 9.50 1.30 2 (1.50 m) 123,694 1,175.09 2.20 2 (2.25 m) 185,542 1,762.65 2 Dike along Left Bank of Chao Phraya River from RID Pak Kret to Rama VII Bridge 11.00 0.97 2 (1.00 m) 82,463 907.09 1.64 2 (1.75 m) 144,310 1,587.41 3 Dike along Left Bank of Chao Phraya River from Rama VII Bridge to Memorial Bridge 7.00 0.86 2 (1.00 m) 82,463 577.24 1.45 2 (1.50 m) 123,694 865.86 4 Dike along Left Bank of Chao Phraya River from Memorial Bridge to Taksin Bridge 9.00 0.72 2 (1.00 m) 82,463 742.17 1.21 2 (1.25 m) 103,079 927.71 5 Dike along Left Bank of Chao Phraya River from Taksin Bridge to Wat Yothin Pradit 21.75 0.57 2 (1.00 m) 82,463 1,793.57 0.82 2 (1.00 m) 82,463 1,793.57 Total 58.25 5,195.16 6,937.20 Northern Dike 1 Local Road from Ban Pho Thong Bon to Road No.306 0.75 1.19 1 (1.00 m) + 3 (0.25 m) 10,360 7.77 1.45 1 (1.00 m) + 3 (0.50 m) 10,763 8.07 2 Road No.306 from Ban Pho Thong Bon to Khlong Rangsit Prayunrasake 1.75 1.19 1 (1.00 m) + 3 (0.25 m) 10,360 18.13 1.45 1 (1.00 m) + 3 (0.50 m) 10,763 18.84 3 Local Road along Khlong Rangsit Prayunrasak to Road No.1 7.25 1.15 1 (1.00 m) + 3 (0.25 m) 10,360 75.11 1.44 1 (1.00 m) + 3 (0.50 m) 10,763 78.03 4 Road No.1 from from Khlong Rangsit Prayunrasak to Soi Phahon Yothin 58 5.25 1.15 1 (1.00 m) + 3 (0.25 m) 10,360 54.39 1.44 1 (1.00 m) + 3 (0.50 m) 10,763 56.51 5 Soi Phahon Yothin 58 to Khlong Hok Wa Sai Lang 1.50 0.93 1 (1.00 m) 9,956 14.93 1.32 1 (1.00 m) + 3 (0.50 m) 10,763 16.14 M-12 6 Local Road along Khlong Hok Wa Sai Lang to Khlong 14 31.25 0.93 1 (1.00 m) 9,956 311.13 1.32 1 (1.00 m) + 3 (0.50 m) 10,763 336.34 Total 47.75 481.46 513.93 Eastern Dike 1 Local Road along Khlong 14 to Road No.3481 12.00 0.80 1 (1.00 m) 9,956 119.47 1.10 1 (1.00 m) + 3 (0.25 m) 10,360 124.32 2 Road No.3481 from Ban Surao Mai to Khet Nong Chok 4.00 0.48 1 (0.50 m) 7,228 28.91 0.78 1 (1.00 m) 9,956 39.82 3 Road No.3481 from Khet Nong Chok to Khlong Phraongchao Chaiyanuchit 12.00 0.48 1 (0.50 m) 7,228 86.74 0.78 1 (1.00 m) 9,956 119.47 4 Local Road along Khlong Phraongchao Chaiyanuchit to Road No.7 18.25 0.34 1 (0.50 m) 7,228 131.91 0.65 1 (0.75 m) 7,228 131.91 5 Local Road along Khlong Phraongchao Chaiyanuchit to Road No.34 8.00 0.00 0.00 6 Local Road from Road No.34 to Chonrahan Phichit Pumping Station and to Road No.3 11.00 0.00 0.00 Total 65.25 367.03 415.53 Appendix M: Adaptation and Proposal Southern Dike 1 Road No.3 from Chonrahan Phichit Pumping Station to Chao Phraya River at Wat Yothin Pradit 39.50 0.00 0.00 2 Road No.3 from Chonrahan Phichit Pumping Station to Bang Pakong River at Amphoe Bang Pakong 24.00 0.00 0.00 Total 63.50 Erosion and 1 Along the coast from the Chao Phraya River Mouth to Khlong Tomru 9.00 0.88 3 (1.00 m) 1,615 14.54 0.88 3 (1.00 m) 1,615 14.54 Wave Protection 2 Along the coast from Khlong Tomru to the Bang Pakong River Mouth 34.00 1.58 2 (1.75 m) 144,310 4,906.54 1.58 2 (1.75 m) 144,310 4,906.54 Total 43.00 4,921.08 4,921.08 Grand Total 10,964.73 12,787.73 Final Report Remark: Type refer to Figure M3.2-1 and unit costs refer to Table M3.2-3 Source: Panya Consultants Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Table M3.2-5 Cost Estimate of Flood Protection Improvement in the Western Area of the Chao Phraya River 30-year Return Period Flood 100-year Return Period Flood Location Description Distance Additional Unit Amount Additional Unit Amount Height Type Cost Height Type Cost (km) (m) (Baht/m) (Million Baht) (m) (Baht/m) (Million Baht) Northern Dike 1 Suanphak Road from Khlong Bangkok Noi to Buddha Monthol Soi 2 Road 8.50 0.00 0.14 1 (0.25 m) 2,894.00 24.60 2 Buddha Monthol Soi 2 Road to Thammasop Road 1.50 0.00 0.14 1 (0.25 m) 2,894.00 4.34 3 Thammasop Road to Road No.3316 21.25 0.00 0.14 1 (0.25 m) 2,894.00 61.50 Total 31.25 90.44 Western Dike 1 Road No.3316 from Ban Tha Talat to Road No.4 20.00 0.00 0.14 1 (0.25 m) 2,894.00 57.88 2 Road No.4 from Ban Suan Som to Ban Rong Hip Phatthana 3.50 0.00 0.00 3 Local Road from Road No.4 to Road No.3091 6.00 0.00 0.00 4 Road No.3091 to Ban Khlong Khae 2.00 0.00 0.00 5 Local Road from Road No.3091 to Amphoe Krathum Baen 5.50 0.00 0.00 6 Local Road from Amphoe Krathum Baen to Road No.3091 14.00 0.46 1 (0.50 m) 4,794 67.12 0.49 1 (0.50 m) 4,794.00 67.12 7 Road No.3091 from Ruang Napha Village to Road No.35 4.00 0.43 1 (0.50 m) 4,794 19.18 0.46 1 (0.50 m) 4,794.00 19.18 8 Road No.35 from Maha Chai Hospital to Ban Khlong Khru 0.75 0.42 1 (0.50 m) 4,794 3.60 0.45 1 (0.50 m) 4,794.00 3.60 9 Local Road from Road No.35 to Wat Sopana Ram 5.50 0.39 1 (0.50 m) 4,794 26.37 0.40 1 (0.50 m) 4,794.00 26.37 10 Local Road from Road No.35 to Khlong Sao Thong 2.50 0.37 1 (0.50 m) 4,794 11.99 0.38 1 (0.50 m) 4,794.00 11.99 Total 63.75 128.24 186.12 Southern Dike 1 Local Road from Khlong Sao Thong-Ban Khom-Ban Sandap-Ban Khok-Ban Ko Pho to Khlong Khun Rat Phinit Chai 20.00 1.13 1 (1.00 m) + 3 (0.25 m) 10,360 207.20 1.18 1 (1.00 m) + 3 (0.25 m) 10,360 207.20 M-13 2 Local Road from Khlong Khun Rat Phinit Chai-Ban Khlong Suan-Ban Khlong Kra Om-Ban Wat Yai Si-Ban Khu Sang Khu Som 17.50 1.13 1 (1.00 m) + 3 (0.25 m) 10,360 181.30 1.18 1 (1.00 m) + 3 (0.25 m) 10,360 181.30 -Ban Santisuk-Ban Sam Ruean to Road No.303 Total 37.50 388.50 388.50 Eastern Dike 1 Dike along Right Bank of Khlong Bangkok Noi from Wat Kai Tia to Chao Phraya River at Bangkok Noi Railway Station 4.50 0.59 2 (1.00 m) 82,463 371.08 0.86 2 (1.00 m) 82,463 371.08 2 Dike along Right Bank of Chao Phraya River to Wat Bang Peung 14.50 0.59 2 (1.00 m) 82,463 1,195.71 0.86 2 (1.00 m) 82,463 1,195.71 3 Local Road from Wat Bang Peung to Road No.303 1.50 0.57 1 (0.75 m) 7,228 10.84 0.82 1 (1.00 m) 9,956 14.93 4 Road No.303 from Wat Bang Peung to Bangkok Phrapra Daeng Hospital 7.25 0.26 1 (0.25 m) 2,894 20.98 0.47 1 (0.50 m) 4,794 34.76 Total 27.75 1,598.62 1,616.49 Canal Improvement 1 Khlong Phasi Charoen 27.00 400 m3/sec 26,273 709.38 0.86 550 m3/sec 36,126 975.40 Appendix M: Adaptation and Proposal 2 Khlong Sanam Chai 32.50 200 m3/sec 13,137 426.94 0.86 350 m3/sec 22,989 747.15 3 Khlong Khun Rat Phinit Chai 14.50 100 m3/sec 6,568 95.24 0.47 250 m3/sec 16,421 238.10 Total 1,231.56 1,960.65 Pumping Station 1 Phasi Charoen Pumping Station 400 m3/sec 10,163.48 0.86 550 m3/sec 13,974.78 2 Sanam Chai Pumping Station 200 m3/sec 5,081.74 0.86 350 m3/sec 8,893.04 3 Khun Rat Phinit Chai Pumpimg Station 100 m3/sec 2,540.87 0.47 250 m3/sec 6,352.17 Total 17,786.08 29,219.99 Erosion and Along the coast from the Chao Phraya River Mouth to the Tha Chin River Mouth 35.75 87,557 3,130.16 87,557 3,130.16 Final Report Wave Protection Grand Total 24,263.17 36,592.35 Remark: Type refer to Figure M3.2-1 and unit costs refer to Table M3.2-3 Source: Panya Consultants Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal Unit: million Baht Return Probability of Flood Damage Cost Flood Damage Cost by Return Period (Year) occurrence Without Project With Project Without Project With Project 10 0.100 91,145 45,465 9,115 4,547 20 0.050 123,308 59,337 6,165 2,967 30 0.033 148,412 71,811 4,947 2,394 50 0.020 148,412 148,412 2,968 2,968 100 0.010 243,902 243,902 2,439 2,439 Flood Damage Cost by Return (million Baht) 10,000 Without Project 8,000 With Project 6,000 4,000 2,000 0 0.010 0.020 0.030 0.040 0.050 0.060 0.070 0.080 0.090 0.100 Probability of Occurrence Source: Panya Consultants’ calculation Figure M3.3-1 Flood Damage Cost With and Without the Project for 30-Year Return Period Unit: million baht Return Probability of Flood Damage Cost Flood Damage Cost by Return Period (Year) occurrence Without Project With Project Without Project With Project 10 0.100 91,145 45,465 9,115 4,547 20 0.050 123,308 59,337 6,165 2,967 30 0.033 148,412 71,811 4,947 2,394 50 0.020 182,387 81,473 3,648 1,629 100 0.010 243,902 101,079 2,439 1,011 10,000 F lood D am age C os t by R eturn (m illion B aht) Without Project 8,000 With Project 6,000 4,000 2,000 0 0.010 0.020 0.030 0.040 0.050 0.060 0.070 0.080 0.090 0.100 Probability of Occurrence Source: Panya Consultants’ calculation Figure M3.3-2 Flood Damage Cost With and Without the Project for 100-Year Return Period M-14 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal In estimating the project benefit – the annual flood damage cost saving, the difference of damage cost at each return flood period is calculated. Then the average interval of damage cost saving is also calculated. For the calculation of the annual damage cost saving the probability of occurrence of each interval flood period is taken to account. The detail calculation of the annual flood damage cost saving for 30 and 100 year return period is presented in Table M3.3-2 and Table M3.3-3. Table M3.3-2 Annual Benefit of 30 Year Return Period Flood Damage Cost Cost Saving (MBaht) Average Interval Return Probability 30-Year Annual Cost With the Interval Probability Period of Without Return Saving Project Damage Cost of (Year) Occurrence the Period (MBaht) 30-Year Return (MBaht) Occurrence Project (MBaht) Period 100 0.01 243,902 243,902 0 0 0.005 0 50 0.02 148,412 148,412 0 0 0.010 0 30 0.03 148,412 71,811 76,601 38,301 0.013 498 20 0.05 123,308 59,337 63,971 70,286 0.017 1,195 10 0.10 91,145 45,465 45,680 54,826 0.050 2,741 Annual Cost Saving 4,434 Table M3.3-3 Annual Benefit of 100 Year Return Period Flood Damage Cost Cost Saving (MBaht) Average Interval Return Probability 100-Year Annual Cost With the Interval Probability Period of Without Return Saving Project Damage Cost of (Year) Occurrence the Period (MBaht) 100-Year (MBaht) Occurrence Project (MBaht) Return Period 100 0.01 243,902 101,079 142,823 50 0.02 148,412 81,473 66,939 104,881 0.010 1,049 30 0.03 148,412 71,811 76,601 71,770 0.013 933 20 0.05 123,308 59,337 63,971 70,286 0.017 1,195 10 0.10 91,145 45,465 45,680 54,826 0.050 2,741 Annual Cost Saving 5,918 Cost Benefit Analysis: The economic viability analysis is carried out for two cases. A base case considers the annual benefit of 4.4 and 5.9 billion baht for floods at a 30-and 100-year return period are constant throughout the analysis period. The other case considers the real value of the infrastructure damage, which will be increased in the future. It is assumed that the growth of real value is on average 3% per year. The detail of the analysis is presented in Table M3.3-4 and Table M3.3-5 for the base case and the real growth of benefit case respectively. The results of the real growth case indicate that the proposed structural measures for the flood protection improvement project are economic feasible for both floods of 30- and 100-year return periods if the opportunity cost of capital is not more than 10%. From this preliminary evaluation, and taking into account that presently Thailand’s low economic discounted rate is approximately 8-9%, the proposal should be designed to protect against floods at a 100-year return period as it provides a higher net return (NPV=13.4 billion baht) than protect against floods at a 30-year return period (11.4 billion baht). Even though the EIRR may not be attractive, the elimination of intangible damages both economic and social and the needs of residents in the business area of Bangkok make the project highly feasible. Therefore, this project should be carried out in the next step in the feasibility study. M-15 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal Table M3.3-4 Cost Benefit Analysis (Base Case) Unit: million baht Project for 30-yr Return Period Project for 100-yr Return Period Year Cost Benefit Net Benefit Cost Benefit Net Benefit 1 21 - - 21 30 - - 30 2 42 - - 42 59 - - 59 3 42 - - 42 59 - - 59 4 1,981 - - 1,981 2,405 - - 2,405 5 3,962 - - 3,962 4,811 - - 4,811 6 9,027 - - 9,027 12,281 - - 12,281 7 12,110 - - 12,110 17,347 - - 17,347 8 8,148 - - 8,148 12,536 - - 12,536 9 584 4,434 3,850 874 5,918 5,044 10 584 4,434 3,850 874 5,918 5,044 11 584 4,434 3,850 874 5,918 5,044 12 584 4,434 3,850 874 5,918 5,044 13 584 4,434 3,850 874 5,918 5,044 14 584 4,434 3,850 874 5,918 5,044 15 584 4,434 3,850 874 5,918 5,044 16 584 4,434 3,850 874 5,918 5,044 17 584 4,434 3,850 874 5,918 5,044 18 584 4,434 3,850 874 5,918 5,044 19 584 4,434 3,850 874 5,918 5,044 20 584 4,434 3,850 874 5,918 5,044 21 584 4,434 3,850 874 5,918 5,044 22 584 4,434 3,850 874 5,918 5,044 23 584 4,434 3,850 874 5,918 5,044 24 584 4,434 3,850 874 5,918 5,044 25 584 4,434 3,850 874 5,918 5,044 26 584 4,434 3,850 874 5,918 5,044 27 584 4,434 3,850 874 5,918 5,044 28 584 4,434 3,850 874 5,918 5,044 29 584 4,434 3,850 874 5,918 5,044 30 584 4,434 3,850 874 5,918 5,044 31 584 4,434 3,850 874 5,918 5,044 32 584 4,434 3,850 874 5,918 5,044 33 584 4,434 3,850 874 5,918 5,044 34 584 4,434 3,850 874 5,918 5,044 35 584 4,434 3,850 874 5,918 5,044 36 584 4,434 3,850 874 5,918 5,044 37 584 4,434 3,850 874 5,918 5,044 38 584 4,434 3,850 874 5,918 5,044 Discount Rate 8% 10% 12% 8% 10% 12% PV of Cost 24,950 21,578 18,831 35,117 30,276 26,349 PV of Benefit 26,969 19,500 14,425 35,995 26,026 19,253 NPV 2,019 - 2,078 - 4,406 878 - 4,250 - 7,096 B/C Ratio 1.08 0.90 0.77 1.02 0.86 0.73 IRR (%) 8.85 8.27 Source: Panya Consultants’ calculation M-16 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal Table M3.3-5 Cost Benefit Analysis (Real Growth) Unit: million baht Project for 30-yr Return Period Project for 100-yr Return Period Year Cost Benefit Net Benefit Cost Benefit Net Benefit 1 21 - -21 30 - -30 2 42 - -42 59 - -59 3 42 - -42 59 - -59 4 1,981 - -1,981 2,405 - -2,405 5 3,962 - -3,962 4,811 - -4,811 6 9,027 - -9,027 12,281 - -12,281 7 12,110 - -12,110 17,347 - -17,347 8 8,148 - -8,148 12,536 - -12,536 9 584 4,434 3,850 874 5,918 5,044 10 584 4,567 3,983 874 6,096 5,222 11 584 4,704 4,120 874 6,278 5,404 12 584 4,845 4,261 874 6,467 5,593 13 584 4,991 4,407 874 6,661 5,787 14 584 5,140 4,556 874 6,861 5,987 15 584 5,294 4,710 874 7,066 6,192 16 584 5,453 4,869 874 7,278 6,404 17 584 5,617 5,033 874 7,497 6,623 18 584 5,785 5,201 874 7,722 6,848 19 584 5,959 5,375 874 7,953 7,079 20 584 6,138 5,554 874 8,192 7,318 21 584 6,322 5,738 874 8,438 7,564 22 584 6,511 5,927 874 8,691 7,817 23 584 6,707 6,123 874 8,952 8,078 24 584 6,908 6,324 874 9,220 8,346 25 584 7,115 6,531 874 9,497 8,623 26 584 7,329 6,745 874 9,782 8,908 27 584 7,549 6,965 874 10,075 9,201 28 584 7,775 7,191 874 10,377 9,503 29 584 8,008 7,424 874 10,689 9,815 30 584 8,249 7,665 874 11,009 10,135 31 584 8,496 7,912 874 11,339 10,465 32 584 8,751 8,167 874 11,680 10,806 33 584 9,013 8,429 874 12,030 11,156 34 584 9,284 8,700 874 12,391 11,517 35 584 9,562 8,978 874 12,763 11,889 36 584 9,849 9,265 874 13,146 12,272 37 584 10,145 9,561 874 13,540 12,666 38 584 10,449 9,865 874 13,946 13,072 Discount Rate 8% 10% 12% 8% 10% 12% PV of Cost 24,950 21,578 18,831 35,117 30,276 26,349 PV of Benefit 36,354 25,439 18,286 48,521 33,954 24,406 NPV 11,404 3,862 -545 13,405 3,678 -1,944 B/C Ratio 1.46 1.18 0.97 1.38 1.12 0.93 IRR (%) 11.69 11.18 Source: Panya Consultants’ calculation M-17 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal M3.4 Non-structural Measures Non-structural measures are essential to mitigate flood damage or risk through various means. They are also necessary to maximize the effect of structural measures. The applicability of the following non-structural measures is summarized as follows: 1) Modification of reservoir operation rule; 2) Groundwater extraction control; 3) Flood disaster response; (1) Flood forecasting and warning system. (2) Flood fighting activity. (3) Disaster recovery. 4) Financial response; (1) Subsidy and taxation. (2) Flood insurance. 5) Watershed management; 6) Disaster management; 7) Strengthening of city and land use control and guidelines; 8) Buildings and housing; 9) Transportation; 10) Water supply and sanitation; 11) Energy; and 12) Public health. Modification of Reservoir Operation Rule Reservoir operation rules of large dams have been revised by agencies concerned with mitigating flood damage downstream of the dams. However, this affects the original functions of reservoir (e.g. reduction of water supply for irrigation and hydropower generation). Therefore during the flooding period, the concerned agencies, such as the Electricity Generating Authority of Thailand (EGAT), the Royal Irrigation Department (RID), the Department of Water Resources (DWR), the Meteorological Department (TMD) and the BMA continue to cooperate while operating reservoirs. Land Subsidence Suppression In Bangkok and vicinities in the Chao Phraya River Basin, land subsidence is one of the major issues related to flood control. Land subsidence is responsible for lowering dike height. Relevant regulations to control and land subsidence should be consolidated. Flood Disaster Response Flood Forecasting and Warning System: A flood forecasting system is one of the solutions to urgently mitigate the flood problem, besides, it also contributes to flood risk management even after the long-term strategic plan is provided. Thus, several flood forecasting systems have been implemented by several agencies in the Chao Phraya River Basin for their own purposes as summarized as follows: 1) TMD operates weather radar stations in the country, making qualitative predictions regarding rainfall for weather forecasts. TMD also installed and operates rainfall gauging stations throughout the country. The data of rainfall stations are transmitted daily to the concerned agencies; 2) EGAT has a flood forecasting system based on a combination of models and empirical techniques. The stream flow component is used to predict the runoff to the Bhumibol and Sirikit Reservoirs for dam operation. Hydrologic data from dams are delivered to the agencies concerned; 3) Since 1831, RID installed and operates stream gauging stations also rainfall stations. Since 1952, many of water level gauges are operated with radio and telephone communication to the central operations office in Bangkok for flood control and M-18 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal protection works. They have developed the telemetric links to monitoring stations and the mathematical model in flood forecasting and warning system in many river basins, including the Chao Phraya River Basin; 4) DWR also installed and operates rainfall and stream gauging stations since 1962; and 5) BMA established a flood control center with telemetric links to monitoring stations of its own for rainfall, water level, pump operation, gate opening, and water quality for inland drainage and flood protection works in the Bangkok metropolitan area. Also, BMA operates one weather radar station in the area. In the currently practiced flood forecasting system, enough forecasting time is assured because of the longer traveling time of flood from upstream to downstream where provision of urgent flood protection works are emphasized and more effective than in the upper basin. To enhance the accuracy of forecasting results and to disseminate the flood prediction results more often, the concerned agencies have improved hydrological observation network, data transmission, management and dissemination systems, and flood forecasting model based on new technology. At present, flood warning is issued by agencies concerned. TMD issues flood warning nationwide based on the weather forecasting results. The warning is issued through the mass media such as the TV, radio, newspapers, and website. DWR and RID issue a warning when a large scale flood is expected on the Chao Phraya River Basin. As the indicator to issue the warning, the flood discharge at Nakhon Sawan is adopted when it is over 3,000 m3/sec. The warning is disseminated to the Governor. Finally, the warning is disseminated to the public through the mass media. BMA issues a warning when a heavy rainfall occurs in the area of Bangkok through the mass media. In view of the issues of the present flood warning system, it is necessary to make it more systematic through the preparation of a guideline for warning systems. The guideline shall specify mainly on (i) objective, role, responsibility and restriction of the warning system, (ii) agency issuing the warning, and (iii) setup of reference points to issue the warning together with the timing of action. Flood Fighting Activity: As well as the establishment of flood forecasting and warning system, flood fighting is also regarded as one of the essential measures as flood disaster response to mitigate flood damage. In the Chao Phraya River Basin, flood fighting is undertaken by the following agencies to protect their respective management areas of responsibility. 1) The Civil Defense Committee has responsibility for policy decisions and planning of flood fighting for all of Thailand. The Department of Disaster Prevention and Mitigation (DDPM) acts as the Secretariat to the Committee; 2) The Department of Drainage and Sewage (DDS) in the BMA is responsible for flood fighting in the Bangkok metropolitan area; 3) The RID is responsible for flood fighting in the agricultural areas; 4) Provincial governments execute flood fighting for the protection of provincial urban areas in cooperation with other agencies concerned; and 5) The military and volunteers assist agencies in flood fighting. To cope with the climate change impacts, we propose that the existing flood fighting activities be further consolidated through: 1) Development of a readily deployable flood fighting system in terms of equipment, materials, and manpower based on past flood fighting experience; 2) Assurance of funds for a flood fighting operation including adequate equipment, materials, and manpower; 3) Period training of inhabitants in flood fighting works; 4) Educational campaign and advertisement on the necessity and modes of the flood fighting system; and 5) Promulgation of a law on flood fighting to clarify the administration structure and responsibilities of agencies concerned. M-19 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal Disaster Recovery: Flood recovery refers to suitable actions that must be taken to bring socioeconomics to normalcy long after the direct damage of a flood has diminished. It is most relevant in the case of a slow-moving disaster like a probable future flood in Bangkok that may last for a prolonged period of time resulting in a secondary disaster (e.g. disease outbreak). We propose that the agencies concerned lay out an individual recovery plan to cope with climate change impacts. Financial Response Subsidy and Taxation: Subsidy for agricultural damage is one of the major current support systems provided by the government. It is established in the Ministry of Agriculture and Cooperatives (MOAC). The major characteristics are: (i) objective - compensate for agricultural damage due to natural disasters such as drought and flood and abnormal insect attacks, and (ii) compensation is in the form of seedlings and fertilizers for subsequent cropping and is not in the form of money, and (iii) the Department of Agriculture Extension (DAE) and the Department of Fisheries (DOF) are responsible for executing compensation. Another support system is reduction of interest on loans provided by the government. For planting, farmers get loans to purchase seeds and fertilizers and to hire machinery for cultivation. In case agricultural products are damaged by flood, the interest on loans is reduced when the farmers repay the money. However, some point out that the level of compensation is less than enough to cover damages, especially flood damage. Thus, strengthening the current support system to further compensate for flood damage and to reduce the interest on loans should be considered. Flood Insurance: Records on subsidy provided by the government indicate that it is not sufficient to support frequent flood-affected farmers. Flood insurance offers promising scope to cope with this shortage. The public sector can play a major role in this respect. So far, several trials on agricultural insurance have been examined in the form of insurance for damage to agricultural products. However, not all trials have been successful mainly due to shortage of funds and insufficient information on insurance premiums. As a result, there is no law on agricultural insurance and no insurance company sells insurance for probable agricultural damage. Moreover, people engaged in agricultural production have no interest in buying such insurance due to lack of information and knowledge, and lack of finances. We propose the government promote agricultural insurance for products and necessary institutional arrangements to strengthen the agricultural insurance system. Watershed Management The influence of deforestation in the upstream catchments on downstream floods remains a matter of research. However, it is widely believed that deforestation may increase peak flood discharge and decrease low water discharge. Until a quantitative evaluation on the subject in Thailand is available, watershed management through logging restrictions and reforestation programs should be encouraged to decrease flood peak discharge and increase recharging capacity of the watershed. The Royal Forest Department (RFD) has responsibility for this matter. Disaster Management In 2002, Thailand established DDPM under the Ministry of Interior (MOI), as the principal agency for disaster management coordination among all agencies concerned at all levels. As regards disaster risk reduction, DDPM has been conducting activities in coordination with other agencies such as MOE, MD, RID, DWR, etc. Disaster management organization of Thailand is presented in Figure M3.4-1. M-20 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Prime Minister or Request International Organization Order Assist Foreign Countries Assigned Deputy Prime Minister Order National Disaster Prevention National Safety Coordinating Coordinating and Mitigation Committee Council of Thailand (NSCT) Assist (NDPMC) Request Assist Assist Request Request Order Ministries, Departments Order Department of Disaster Request Prevention and Mitigation Coordinating Request (DDPM) (Ministry of Defence) Assist Assist Order Provincial Governer Request Request M-21 Army Forces Assist or Assist DPPM Regional Center BMA Governer Assist Order Request Assist Request Request Request District, Municipality, Order Private Sectors Order Neignboring Order Assist Pattaya Municipality, Provinces Assist Tambon Administrative Organization (TAO) Request Order Order Order Neighboring District Supplement Supplement Appendix M: Adaptation and Proposal Disaster Volunteers Municipality, TAO Emergency Response Team Emergency Response Team Emergency Response Team Emergency Response Team Emergency Response Team Emergency Response Team Emergency Response Team (ERT) (ERT) (ERT) (ERT) (ERT) (ERT) (ERT) Disaster Area Source: DDPM, 2009 Final Report Source: DDPM, 2009 Figure M3.4-1 Disaster Management Organization Chart of Thailand Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal National Civil Defense Committee (NCDC): It coordinates all activities relevant to civil defense and disaster management. NCDC performs all functions relevant to management of disaster at national level, such as formulation of Civil Defense Master Plan, evaluation of the implementation of the above-mentioned plan by an audit mission, organizing annual or periodical training courses on civil defense and disaster management for government officials at all levels and for the general public, issuing regulations on the payment of remuneration, compensation and other expenditures relevant to civil defense and disaster management activities carried out by all agencies concerned. National Safety Council of Thailand (NSCT): Apart from NCDC, Thailand has another disaster management related mechanism which has highlighted its tasks and responsibility on man-made disaster management only that is NSCT. The NSCT has been established in 1982 on the ground of the problem of road traffic accidents in Thailand which annually resulted in tremendous loss of lives, properties, and national economy. Later on, its responsibilities have been extended to cover the prevention of chemical accident, occupational accident, accident in home and public venues, considering preventive measure of fire in high-rise building, accident prevention in subway tunnel construction, providing education of safety, etc. National Disaster Warning Center (NDWC): NDWC was established under the order of the Office of the Prime Minister. It is now under the Ministry of Information and Communication Technology (MICT). The major task is to detect earthquake and to analyze seismic data to determine the possibility of a Tsunami generation before issuing notification messages to the public and related authorities and rescuers for evacuation of people into safe places. This is to prevent the loss of people’s lives and properties as much as possible. From now on, NDWC will be developed, upgraded of its early warning system and extended its telecommunication networks to be able to cope with multi-hazards disasters apart from Tsunamis. Thailand urgently needs to reform disaster management systems and mechanisms as follows: 1) Public Awareness and Education: Improve public safety of every sector, particularly those who are living with risk, by enhancing people’s understanding of the threats posed by various types of disasters; 2) Materializing Early Warning Systems: Following the catastrophic tsunami disaster in 2004, Thailand took immediate action to establish NDWC, which covers the warning of both natural and man-made disasters; 3) Establishing More International Disaster Management Networks: Thailand needs to enhance the country’s disaster management capacity and efficiency through the mobilization of technical assistance from foreign countries, particularly from developed and advanced countries; 4) Effective Damage Assessment: Remote survey technology must be introduced to effectively assess the damages caused by large scale disaster. The staff of the agencies concerned need to be trained to enhance their capacity in applying satellite images to assess the damage; 5) Application of Community-Centered Approach: Local authorities and communities are in the front line in the event of disaster occurrence, consequently, they are the most vulnerable and affected. It is indispensable to enhance their potential in responding to disasters, and to equip them with awareness and preparedness; 6) Highlight a Preventive Approach: The new approach of disaster management has shifted its focus from assistance or relief to prevention. In this regard, risk reduction to be vigorously taken into account. So as to reduce risk, both structural and non-structural measures should be materialized. Thus, the cost of risk reduction will yield an invaluable rate of return when compared with the cost of disaster damage; 7) A Focus on Prevention: Proactive disaster management can reduce the damage and impact substantially; 8) A Focus on Public Participation: Past disaster management in Thailand underlined the roles of government agencies and simply ignored private sectors, non-government M-22 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal organizations, communities and even the public. Unfortunately, there has been a lack of cooperation among agencies concerned. This is a real challenge for DDPM to bring these stakeholders together; 9) A Focus on Unity in Management: The application of the Incident Command System (ICS) will demonstrate unity in management; 10) A Focus on Efficient Communication: An efficient communication system consists of the major system and the reserved system, which are vital for disaster management; 11) A Focus on Human Resource Development: Human resource development is a key factor for disaster management; and 12) Livelihood Rehabilitation: Livelihood rehabilitation activities such as community development, vocational training, and improving the standards of living should be immediately materialized to normalize disaster victims’ means of living. Disaster Management Plan: The Civil Defense Secretariat is responsible for identifying disaster prevention measures and policies and the National Civil Defense Plan. This plan serves as the master plan for all agencies concerned, and provides guidelines for the formulation of operational plans of agencies responsible for management of disasters. The Civil Defense Secretariat does not only implement policies, but also provides equipment, technical assistance, and training courses for local agencies and the public. It also coordinates with agencies that are in charge of disaster relief and rescue operations. According to the Civil Defense Act B.E.2522 (1979), the functional agencies are responsible for formulating their own disaster management plan. The master disaster management plan regarded as a national civil defense plan is to be made by the Civil Defense Secretariat. The plan is to be reviewed and updated every three-year term and proposed to the National Civil Defense Committee for approval. The current national civil defense plan, which was reviewed and updated in 2008, consists of two components: Disaster Prevention and Mitigation and Civil Defense for Security (Rear-Area Protection). Strengthening of City and Land Use Control and Guidelines In the Chao Phraya River Basin, land development is being promoted in accordance with economic growth. Thus, it is necessary to control land use and provide guidance to land development to minimize the increase of flood damage potential and decrease of its flood retarding function. To control disorderly land use, it is essential to prepare a flood risk map that will show not only the flood risk area but also the retarding area. Land development shall thus be guided according to the flood risk map. If land development is planned in a habitually inundated area, protection works shall be obligatory to minimize the flood damage potential. Moreover, land development with the provision of public facilities shall be planned by referring to the flood risk map to minimize the decrease of its retarding function. Among public facilities, roads in a flood prone area are vulnerable to flood damage and they sometimes hamper the free movement of floodwater resulting in the loss of a retarding function. The construction of roads shall be planned in consideration of flood risk by minimizing the damage potential and not decreasing the retarding function of the flood prone area. Other infrastructures should be designed or improved based on the flood risk map. Buildings and Housing In principle, the climate change adaptation and mitigation measures on building and housing can be classified into two groups. The first group concerns design and construction, such as promoting energy-efficient design and buildings, energy-efficient technologies, construction practices encouraging greater use of natural light and ventilation, proper insulation and energy conservation measures. The second group is mitigation measures designed for flood risk areas, such as drainage systems, dikes and polders or diversion channels for the area; and non-structural measures, such as land use control, building site elevation and location adjustment and flood fighting management. Both categories of adaptation and mitigation measures need to be supported by proper rules and M-23 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal regulations for enforcement; thus the institutional mechanism must be arranged so the legal system can realize those measures. At present, there are several laws enacted to control and guide the developments in all urban areas including Bangkok metropolitan area. The laws which are closely concerned with the climate change adaptation and mitigation measures will be discussed as follows: The Town and Country Planning Act B.E.2535 (1992): The Town and Country Planning Act was promulgated to promote the effective and ordinal land use in accordance with the future expansion of local communities in the context of national economic and social development plan. The Act is featured with the provision of two types of plan: General Comprehensive Plan (GCP) and Specific Development Plan (SDP). The GCP is a plan, policy and land use control measures used as guideline for developing and maintaining a town and related areas and/or the countryside in respect of property usage, communication and transportation infrastructure, public service and environment in order to achieve the objectives of town planning. The output of the GCP will comprise of a set of plans prescribing the classified land use zones and use class regulation for each land use type, plan for open space, plan for communication and transportation network, plan for public utility and implementation means and measures. According to the Act, the DPT is empowered to prepare the GCP for the whole country. However, at present, the plan preparation and implementation have been delegated to be the responsibility of the local government administration. The present Bangkok GCP (2006) has been prepared by the Department of City Planning, BMA. It is noticeable that the Bangkok GCP is the only the GCP that has been prepared by local government agency. The SDP is the project plan for developing, maintaining or rehabilitating a specific area as guided by the GCP. As noted, the name of the plan, it shows the more specific and detailed contents of the plan more than that of GCP. The SDP consists of a set of plans showing the prescription of classified land use in each parcel of land, type and kind of land development, system of public roads and paths, plot ratio, details of public utilities, open space, ground level, and so on. In comparison with GCP, the SDP would be more effective for land use control and guidance since the SDP contain the complete set of area development prescriptions ready for effectuation. However the preparation and announcement of the SDP would face more opposition forces from the affected land owners because SDP will become the expropriation order for all land that planned for public uses in contrast of the GCP which governed with fewer prescriptions-mainly the restriction on the choices of land use type only. As a result, there is still no SDP for the urban centers including Bangkok. According to the Act, the GCP needs to be revised every five year after plan announcement; thus the Bangkok GCP will be targeted for revision on the year 2011. On this occasion, the climate change adaptation and mitigation measures should be applied on the revised land use plan especially over the flood-risk areas in order to protect and/or reduce the adverse effects and damages caused by such impact. The land use in the flood-risk zone should be overlaid by the selected measures that pertinent to the reduction of flood damages and risks of death and injury from the flood inundation. The discouragement of the use of land for intensive developments in flood-risk zone also should be recommended. The Building Control Act B.E.2522 (1979): The Building Control Act is primarily intended to control the design, construction, alteration, removal, demolition and use of the buildings, which could affect to a certain extent, types of land use and density of population. In the Act, it is authorized that the Minister of Interior, with the instruction of the Building Control Committee can issue the ministerial regulations concerning a number of matter related to buildings for the purposes of security, strength, safety, fire protection, sanitation, environmental quality protection, town planning, architecture, traffic facilitation, and other matters necessary for compliance with M-24 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal the Act. Apart from the building control functions as identified from the name of the Act, the Act is also concerned with land use control in some specific areas that is sensitive to the livelihood and well-being of the public. And thus when the construction of buildings are planned in the flood inundation area, the Act may be used to control and guide the development of building to minimize the flood damages. In this respect, the Building Control Act can stipulate the prohibition order to the construction and/or building usage for some kinds and types of building that are unsuitable to be built and operated in those specific areas. The BMA has utilized this special power in several places and areas such as the restriction of shop-houses in lining up both sides of the major arterial streets, conservation of historical sites and areas, building height control around the major monuments and approach zones of the airport, and others. From these examples, the application of this stipulation can be adopted to enforce the climate change adaptation and mitigation measures to the affected areas of the city as far as the building and housing are concerned. This stipulation should be used in conjunction with the land use plan as mentioned earlier. The Enhancement and Conservation of Natural Environmental Quality Act B.E.2535 (1992): The Enhancement and Conservation of Natural Environmental Quality Act is intended for controlling land use in the environmentally sensitive areas. The Act states that the Minister of Science, Technology and Environment with the instruction of the National Environmental Board may issue a ministerial regulation designating an area processing the environmental sensitive characteristics as an “environmentally protected area” needed to be planned for protection, enhancement and conservation of the natural environmental quality. The area may be the headwater, or have a distinguishing or fragile ecology, or have the natural or artistic value. The Act states that the ministerial regulation may issue the following prescriptions: 1) Land use prescription for the conservation of the nature or prevention of adverse impacts upon an ecological system or artistic environment; 2) Prohibition of activities harmful to or likely to alter the ecosystem or adversely affecting the value of artistic environment; 3) Specification of types and sizes of project or activity having the environmental impact with assessment report, which would have to be prepared before the construction or operation begin in that project; 4) Determination of method for managing the area including the determination of scope, duty and responsibility or relevant governmental agencies for the purpose of cooperation and coordination in increasing their performance and protecting the ecosystem and value of artistic environment; and 5) Prescription of other protective measures as necessary and suitable for that area. The Act stipulates that in case of designating a particular locality that already belongs to a conservation, general comprehensive town planning, specific development town planning, building control, industrial estate or pollution control area, if it faces a critical environmental problem, which urgently needs remedy and could not be effectively handled by the relevant agencies in time, the Minister of Science and Technology with the approval of the National Environmental Board, would be able to issue the protective measures to regulate land use and some activities in order to assist the proposed environmental mitigation action for that area. In this respect, it is possible to designate the flood-risk area in Bangkok metropolitan area as the environmentally protected area, so that the flood adaptation and mitigation measures can be put to use in the area. These measures should be harmonized with the town planning land use overlay and building control prohibition area in both area and regulatory control items. For the institutional mechanism set up to exercise the legal arrangements as mentioned earlier, the responsibility has been laid down to be the duty of the national level agencies of the central governmental ministries and BMA at the local level. At the national level, the major agencies are M-25 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal the Ministry of Natural Resource and Environment, Ministry of Science and Technology, Ministry of Interior, and other related agencies such as the Royal Irrigation Department, the Meteorological Department, the Department of Highway, etc. In case of the BMA, there are several departments assigned to handle all problems of urban development and the related duties such as: 1) Department of City Planning is responsible for plan preparation and enforcement of the metropolitan land use plan; 2) Department of Public Works is responsible for all public works and building control; 3) Department of Drainage and Sewerage is responsible for flood protection and sewerage treatment; and 4) Department of Environment is responsible for environmental protection and improvement. It is interest to note that all affairs concerned with housing, both average housing and condensed housing will be looked after by the Department of Social Development. In performing the job, the Department develops the housing community and neighborhood system for all housing settlements in the city and sets up a group of housing community council in each neighborhood. The local councils will work with the Department in all matters that are concerned with the community life and livelihood of the public at large. Through this channel, the concept of climate change adaptation and mitigation measures can be proposed for action to the people at the grass root. As far as the managements on the climate change impacts are concerned, the BMA has been working closely with all agencies at the national level, especially with the Ministry of National Resources and Environment (MONRE). At this moment, the administration is actively joined together with the Environmental Research and Training Center of the Department of Environment and Quality Promotion (DEQP) in vigorously launching the campaign on public awareness on this matter and preparing for the climate change strategy in the near future. Transportation For the A1FI scenario of climate change, extreme rainfall intensity (mm per hour) would increase 15% over current levels. However, every civil design uses current levels for flood prevention and drainage requirement. Thus, the major infrastructures should use design criteria and be reviewed according to climate change conditions. Considering global warming cities’ objectives are typically to meet the mobility needs of citizens while minimizing the amount of the Greenhouse Gas (GHG) and air pollutants emitted, to create and operate functioning public transport systems and to reduce traffic and congestion. Managing the emissions from transport and traffic congestion is generally best achieved through the following policies (WB, 2008): 1) Managing and controlling vehicular usage; 2) Improving fuel efficiency of vehicles and promoting efficient modes of transport; 3) Promoting use of cleaner fuels and green vehicles; and 4) Developing economic instruments for congestion and pollution control in urban areas. Water Supply and Sanitation The whole waterworks, conduit and sewerage systems should be checked according to regulations and climate change conditions to reduce damages. Some can endure severe floods and ground subsidence, but others may need to be repaired and strengthened. Energy The design criteria for generation facilities should be strengthened in order to endure climate change because it can affect hydraulic, geographical and geological circumstances. Therefore, the design criteria should be reviewed to incorporate impacts of climate change. M-26 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix M: Adaptation and Proposal With an eye on global warming, the most common strategies for mitigation in the energy sector are improving power generation efficiency, encouraging the move toward cleaner and less carbon- intensive fuels, keeping electricity costs affordable, and developing public/private partnerships (WB, 2008). Public Health Although the statistics of the Ministry of Public Health do not suggest any causal relationship between recent floods and communicable waterborne diseases, the Ministry pointed out that diseases such as mosquito-borne diseases, skin diseases, and gastrointestinal diseases are remarkable when flood inundation is prolonged. To prevent such waterborne diseases, the Ministry makes effort to provide drinking water and first aid kits, including deployment of ambulances and district and sub-district health officers assisted by volunteers. With global warming in mind, climate change has been identified as causing changes in the pattern of communicable diseases throughout the world. It may also lead to more heat-related diseases among the most vulnerable in society: the young, the elderly, and the sick and disabled. Tropical cities have developed specific communicable disease strategies, such as vector control (mainly against mosquitoes, flies, cockroaches and rodents) and light protections (tents and curtains) (WB, 2008). M-27 APPENDIX N CONSULTATION WITH STAKEHOLDERS Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix N: Consultation with Stakeholders APPENDIX N CONSULTATION WITH STAKEHOLDERS N1 TECHNICAL CONSULTATION 1 Date and Venue The meeting was held on September 23, 2008 at Chaiyo Training Room, the World Bank Office, Bangkok. Consultation Program 12:30 – 13:00 Register 13:00 – 14:30 “Sea Level Rise and Land Subsidence in the Bangkok Metropolitan Area” presented by the Consultant 14:30 – 15:00 Coffee break 15:00 – 16:30 Discussion with concerned agencies 16:30 – 17:00 Summary and end of the meeting List of Participants Name Organization 1 Mr. Chinat Niyomtoon Department of Drainage and Sewerage, BMA 2 Mr. Parinya Jantakoop Department of Drainage and Sewerage, BMA 3 Mrs. Pataramon Prasitwatanachai Department of Drainage and Sewerage, BMA 4 Mr. Teerayuth Khunmak Department of Drainage and Sewerage, BMA 5 Mrs. Suwanna Jungrungrueng Environmental Department, BMA 6 Mrs. Supathanee Panurat Department of City Planning, BMA 7 Dr. Orapim Pimcharoen Department of City Planning, BMA 8 Mr. Chaiporn Siripornpibul Bureau of Groundwater Conservation and Restoration 9 Mr. Poolsup Somboonpanya Department of Public Works and Town & Country Planning 10 Col. Choksak Aiyasanont Royal Thai Department 11 Lt. Col. Anupong Prongchit Royal Thai Department 12 Ms. Nisakorn Kositratna Department of Marine and Coastal Resources 13 Ms. Narumol Kornkanitnan Department of Marine and Coastal Resources 14 Ms. Suhatai Praisankul Department of Marine and Coastal Resources 15 Lt. Col. Supasit Kongdee Hydrographic Department, Royal Thai Navy 16 Mr. Weerasak Sai-ngam Marine Department 17 Mr. Rapeepun Sansanit Marine Department 18 Mr. Rangsiwut Sohhab Marine Department 19 Dr. Noppadol Phienwej Geotechnical and Geoenvironmental Engineering Program, AIT Department of Survey Engineering, Faculty of Engineering, 20 Assoc. Prof. Dr. Itthi Trisirisatayawong Chulalongkorn University Department of Survey Engineering, Faculty of Engineering, 21 Assoc. Prof. Dr. Chalermchon Satirapol Chulalongkorn University Geotechnical Engineering Research and Development Center, 22 Dr. Apiniti Jotisankasa Kasetsart University Geotechnical Engineering Research and Development Center, 23 Mr. Sutham Rotchanameka Kasetsart University Geotechnical Engineering Research and Development Center, 24 Mr. Santi Thaiyuenwong Kasetsart University 26 Mr. Bradford R. Philips World Bank 27 Mr. Manuel Cocco World Bank 28 Dr. Lert Chuntanaparb Panya Consultants Co., Ltd. 29 Assoc. Prof. Dr. Seree Supharatid Panya Consultants Co., Ltd. 30 Mr. Tepawan Wattanaprateep Panya Consultants Co., Ltd. 31 Mr. Vanchai Sothikul Panya Consultants Co., Ltd. 32 Ms. Bantitha Khantisidhi Panya Consultants Co., Ltd. N-1 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix N: Consultation with Stakeholders N2 TECHNICAL CONSULTATION 2 Date and Venue The meeting was held on February 19, 2009 at, Keelawet 3 Building, Bangkok Metropolitan Youth Center, Bangkok. Consultation Program 13:00 – 13:30 Register 13:30 – 13:40 Consultation opening 13:40 – 14:10 “Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region” presented by the Consultant 14:10 – 15:45 Discussion with concerned agencies 15:45 – 16:00 Summary and end of the meeting List of Participants Name Organization 1 Mr.Chanchai Vitoolpanyakij Department of Drainage and Sewerage, BMA 2 Mr.Chainat Niyomthoon Department of Drainage and Sewerage, BMA 3 Mr. Wichai Somboon Department of Drainage and Sewerage, BMA 4 Mrs. Suwanna Jungrungrueng Department of Environment, BMA 5 Ms. Weeraporn Tanchatchawan Department of Environment, BMA 6 Ms. Wontana Wuttigingyong Department of Environment, BMA 7 Ms. Nitsara Thamchevevong Department of Environment, BMA 8 Dr. Orapim Pimcharoen Department of City Planning, BMA 9 Mr. Khunavuthi Prapan Traffic and Transportation Department, BMA 10 Mr. Natthachai Boonthong Bangkok Fire and Rescue Department, BMA 11 Ms. Pornapa Methaweewongs Strategy and Evaluation Department, BMA 12 Mrs. Hataiporn Nauwaphut Budget Department, BMA 13 Ms. Pisamai Phayakarinlak Budget Department, BMA 14 Mr. Supornpol Nukrongsen Social Development Department, BMA 15 Mr. Chareon Weeraachagool Health Department, BMA 16 Ms. Dawruang Dechaop Department of Ground Water Resources 17 Mr. Sakchai Sathianrapapong National Housing Authority 18 Ms. Areerat Yooltoon Department of Alternative Energy Development and Efficiency 19 Ms. Siriluksano Duangkeo Department of Disaster Prevention and Mitigation 20 Mrs.Somsri Avakeat Department of Marine and Coastal Resources 21 Mr. Jirat Laksanalamai Marine Department 22 Ms.Wanida Suksuwan Thai Meteorological Department 23 Capt. Tanapol Vichailukkana Hydrographic Department 24 Mr. Supat Wattayu Royal Irrigation Department 25 Mr. Saharat Pimpasak Department of Public Works and Town & Country Planning 26 Dr. Plernpit Suwan-ampai Department of Disease Control 27 Mr. Pirat Tangkaseranee The Federation of Thai Industries 28 Dr. Noppadol Phien-wej Geotechnical and Geoenvironmental Engineering Program, AIT 29 Dr. Kanchana Nakapakorn Environment and Resources Faculty, Mahidol University 30 Ms. Pongtip Puvacharoen World Bank 31 Mr. Prasit Povilai Panya Consultants Co., Ltd. 32 Assoc. Prof. Dr. Seree Supharatid Panya Consultants Co., Ltd. 33 Mr. Tepawan Wattanaprateep Panya Consultants Co., Ltd. 34 Mr. Vanchai Sothikul Panya Consultants Co., Ltd. 35 Mr. Surapon Brahmakasikara Panya Consultants Co., Ltd. 36 Mr. Chaiwat Prechawit Panya Consultants Co., Ltd. N-2 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix N: Consultation with Stakeholders List of Participants (Cont’d) Name Organization 37 Mr. Chalerm Keokungwal Panya Consultants Co., Ltd. 38 Dr. Vongchai Jarenswan Panya Consultants Co., Ltd. 39 Ms. Chutharat Pang-utha Panya Consultants Co., Ltd. 40 Mr. Tavorn Boonrasri Panya Consultants Co., Ltd. 41 Ms. Bantitha Khantisidhi Panya Consultants Co., Ltd. 42 Ms. Roograwee Juthasawat Panya Consultants Co., Ltd. 43 Ms. Nipawan Wangvilai Panya Consultants Co., Ltd. N3 FINAL STAGE CONSULTATION Date and Venue The meeting was held on March 12, 2009 at the Grand Ayutthaya Hotel, Bangkok. Consultation Program 09:00 – 09:30 Register 09:30 – 09:45 Consultation opening 09:45 – 10:30 “Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region” presented by the Consultant 10:30 – 10:50 Coffee break 10:50 – 11:50 Discussion 11:50 – 12:00 Summary and end of the meeting List of Participants Name Organization 1 Dr. Prakob Chirakiti Deputy Bangkok Governor, BMA 2 Mr. Chanchai Vitoolpanyakij Department of Drainage and Sewerage, BMA 3 Mr. Chainat Niyomtoon Department of Drainage and Sewerage, BMA 4 Mr. Vichai Sombun Department of Drainage and Sewerage, BMA 5 Mrs. Suwanna Jungrungreung Department of Environment, BMA 6 Ms. Woranuch Suaykakaow Department of Environment, BMA 7 Mrs. Siriporn Tantivanich Department of Environment, BMA 8 Ms. Nateetip Jonganukoontanakorn Department of Environment, BMA 9 Dr. Orapim Pimcharoen Department of City Planning, BMA 10 Ms. Anchalee Pattamasawan Department of City Planning, BMA 11 Mr. Prapan Khunavuthi Traffic and Transportation Department, BMA 12 Ms. Pornnapa Methaweewongs Strategy and Evaluation Department, BMA 13 Ms. Chutimon Ampan Strategy and Evaluation Department, BMA 14 Ms. Siriporn Arayapongchai Budget Department, BMA 15 Ms. Pissamai Phyakarintarungkul Budget Department, BMA 16 Ms. Dudsadee Suangkhan Bureau of Social Development, BMA 17 Mr. Charoen Weeraachakool Department of Health, BMA 18 Mr. Pramote Jaiyen City Law Enforcement Department, BMA 19 Mr. Maitree Budhawong Office of Tourism Development, BMA 20 Mrs. Rossukhon Chartprasert BMA 21 Mr. Nattapon Wattanavong Bang Kho Laem District Office 22 Mr. Sommai Naisin Bang Kho Laem District Office 23 Mrs. Chavaporn Piyatassakorn Bang Khun Thian District Office 24 Mr. Phasit Hunsadee Bangna District Office 25 Ms. Nonglak Chinanavin Khlong San District Office 26 Mr. Prajuk Wongwutti Klong Toei District Office N-3 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix N: Consultation with Stakeholders List of Participants (Cont’d) Name Organization 27 Ms. Somjai Lasian Phra Khanong District Office 28 Mr. Bapit Sangkaew Rat Burana District Office 29 Mr. Virapon Vongsiri Rat Burana District Office 30 Mr. Aran Bunmirat Thung Khru District Office 31 Mr. Niran Puwathanarak Yannawa District Office 32 Mr. Chairat Tongkon Nakhon Pathom Provincial Office 33 Mr. Chalong Kongdoem Nonthaburi Provincial Office 34 Mr. Viranit Srioum Samut Prakan Provincial Office 35 Mr. Virasak Khanchai Samut Sakhon Provincial Office 36 Mr. Kitja Mokcharoen Department of Provincial Administration 37 Mr. Mongkol Khaimook Department of Marine and Coastal Resources 38 Mr. Rapeepun Saensanit Marine Department 39 Ms. Narumol Kornkantinan Marine and Coastal Resources Research Center 40 Mr. Adichat Surinkum Department of Mineral Resources 41 Mr. Sombut Choedchutum Department of Water Resources 42 Mr. Chaiporn Siripornpibul Department of Groundwater Resources 43 Mr. Pradit Artsantachai Metropolitan Waterworks Authority 44 Dr. Wacharin Pookaothong Provincial Waterworks Authority 45 Mrs. Siriyakorn Chaisawat The Electricity Generating Authority of Thailand 46 Ms. Sasiluksana Khamsiri The Electricity Generating Authority of Thailand 47 Ms. Areerat Yoohoon Department of Alternative Energy Development and Efficiency 48 Mr. Ratrueang Chotwit Office of Natural Resources and Environmental Policy and Planning 49 Mr. Atsamon Limsakul Department of Environmental Quality Promotion 50 Ms. Vimonrat Leephisuth Department of Environmental Quality Promotion 51 Ms. Naboon Riddhiraksa Pollution Control Department 52 Mr. Saharat Pimsak Department of Public Works and Town & Country Planning 53 Mr. Thavatchai Pimsarn Department of Highways 54 Mrs. Juthamard Yensudjai Expressway Authority of Thailand 55 Mr. Nirun Kongritti Expressway Authority of Thailand 56 Mr. Thongchai Suprakran Port Authority of Thailand 57 Mr. Polavuth Katawandee The State Railway of Thailand 58 Mr. Sucheep Suksawang The State Railway of Thailand 59 Mr. Nopporn Jaroongkiat Office of Transport and Traffic Policy and Planning 60 Mr. Chainarong Vasanasomsithi Department of Disaster Prevention and Mitigation 61 Mr. Morakot Waraporn Department of Disaster Prevention and Mitigation 62 Ms. Phatsita Rerngnirunsathit Department of Disaster Prevention and Mitigation 63 Ms. Chutima Bunrod Department of Disaster Prevention and Mitigation 64 Mrs. Pornpen Leelapun Department of Social Development and Welfare 65 Mr. Tanasan Laksanachai Department of Medical Services 66 Mr. Shutsana Narkthon Department of Mental Health 67 Mr. Kamol Subwik Department of Mental Health 68 Dr. Swisuk Punpeng Department of Health 69 Ms. Nawarat Tongnoo Department of Health 70 Mr. Pongsak Sukrat Department of Health 71 Mr. Bancha Leelaniphawan Department of Health Services Support 72 Mr. Pairat Tangkaseranee The Federation of Thai Industries 73 Mr. Phiya Phusakaew National Institute of Metrology 74 Assoc. Prof. Dr. Wisakha Phujinda National Institute of Development Administration 75 Mrs. Tharee Kamueang Thailand Environment Institute N-4 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report Appendix N: Consultation with Stakeholders List of Participants (Cont’d) Name Organization 76 Ms. Mayuree Krondeelard Thammasat University 77 Ms. Kodchaporn Sirichaisakul Thammasat University 78 Ms. Kulwadee Kitsaneepibul Thammasat University 79 Mr. Mana Yudee The Government Public Relations Department 80 Mr. Pranat Satapatnon The Government Public Relations Department 81 Mr. Sira Leepipatnavit Green World Foundation 82 Mr. Noppayut Pichainarong Thailand Greenhouse Gas Management Organization 83 Mrs. Natarika Vayaparb Cooper Thailand Greenhouse Gas Management Organization 84 Mr. Naphayut Phichainarong Thailand Greenhouse Gas Management Organization 85 Mr. Charin Waenngern Foundation for Quality of Life Development 86 Mr. Vikrom Vibhadakul Foundation of Quality of Life Development 87 Ms. Junjit Sirthammasat Foundation of Quality of Life Development 88 Ms. Napalai Transukkajang Heritage Siam-Asia Inter Co., Ltd. 89 Ms. Apriradee Troesan Heritage Siam-Asia Inter Co., Ltd. 90 Ms. Chula Janrueng Heritage Siam-Asia Inter Co., Ltd. 91 Ms. Montira Phiyasakul Morocco Embassy 92 Mr. Peter Zanten Netherlands Embassy 93 Mr. Jan Bojo World Bank 94 Mr. Manuel Cocco World Bank 95 Ms. Buntarika Sangarun World Bank 96 Ms. Pongtip Pavacharoen World Bank 97 Assoc. Prof. Dr. Seree Supharatid Panya Consultants Co., Ltd. 98 Dr. Lert Chuntanaparb Panya Consultants Co., Ltd. 99 Mr. Tepawan Wattanaprateep Panya Consultants Co., Ltd. 100 Mr. Thanate Bumrungcheep Panya Consultants Co., Ltd. 101 Mr. Surapon Brahmakasikara Panya Consultants Co., Ltd. 102 Mr. Chalerm Keokungwal Panya Consultants Co., Ltd. 103 Ms. Chutharat Pang-utha Panya Consultants Co., Ltd. 104 Ms. Bantitha Khantisidhi Panya Consultants Co., Ltd. 105 Ms. Roograwee Juthasawat Panya Consultants Co., Ltd. 106 Ms. Nipawan Wangvilai Panya Consultants Co., Ltd. N-5 REFERENCES Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report References REFERENCES AIT, 2004. “An Assessment of the Socio-Economic Impacts of Floods in Large Coastal Areas”, Final Report for APN CAPaBLE Project: 2004-CB01NSY-Dutta. BMA, 1998a. “Wastewater User Charge Study” prepared by the Progress Technology Consultant Co., Ltd. and Metcalf & Eddy International, Inc. BMA, 1998b. “Statistics of Wastewater Plants under the BMA” prepared by the Department of Drainage and Sewerage. BMA, 2005. “The Study, Survey, Design, and Master Plan of Drainage System in the Areas of Bangkok Noi, Bangkok Yai, Thonburi, Rat Burana, Thung Kru, and Some Areas of Bang Khun Thian Districts” prepared by the Team Consulting Engineering and Management Co., Ltd. (report in Thai). BMA, 2006a. “Bangkok Communities” prepared by Community Development Division, Office of Social Development. BMA, 2006b. “Bang Sue Environmental Education and Conservation Report” prepared by the Department of Drainage and Sewerage. BMA, 2006c “Bangkok State of the Environment 2005” prepared by the Department of Environment. BMA, 2006d. “Solid Waste Management in Bangkok 2005” prepared by the Department of Environment. BMA, 2007a. “Coastal Erosion Protection of Bang Khun Thian District, Bangkok” prepared by the Consultant of Technology Co., Ltd. in association with Panya Consultants Co., Ltd (report in Thai). BMA, 2007b. “Bangkok Action Plan for Global Warming Mitigation 2007-2012” prepared by the Department of Environment. BMA, 2007c. “The Water Quality of 7 Central Water Treatment Plant in Bangkok” Available online: http://dds.bma.go.th/News_dds/information/Plant/7E.htm. BMA, 2007d. “The Water Quality of 15 Community Water Treatment Plant in Bangkok” Available online: http://dds.bma.go.th/News_dds/information/15Plant/15E.htm. BMA, 2007e. “Water Environmental Control Plant in Bangkok” Available online: http://dds.bma.go.th/News_dds/information/projectE1.htm. BMA, 2007f. “Water Quality Management in Bangkok” Available online: http://dds.bma.go.th/News_dds/information/wastewater_management (EngVer)1.pdf. BMA, 2007g. “The Nong Jok Garden City Project” prepared by Panya Consultants Co.,Ltd. And Phisut Technology Co.,Ltd. (report in Thai). BMA, 2008a. “Operation Plan for Bangkok Flood Protection in 2008” prepared by the Department of Drainage and Sewerage, Bangkok (report in Thai). BMA, 2008b. “Action Plan for Prevention and Mitigation of Flood for BMA” prepared by the Department of Drainage and Sewerage. BMA, 2008c. “Plan for Flood Protection of BMA Map” prepared by the Department of Drainage and Sewerage. BMA, 2008d. “Master Plan of Drainage System for Bangkok Noi, Bangkok Yai, Thonburi, Rat Boorana, Thung Kru, Bang Khun Thian, Final Report” prepared by the Department of Drainage and Sewerage. BMA, 2008e. “Epidemiological Report of Diseases in Bangkok” prepared by the Bureau of Health (report in Thai). BMA, 2008f. “The Amount of Solid Waste in Transfer Station Record in the Fiscal 2008” prepared by the Department of Environment. BMA, 2008g. “Annual Report 2007” prepared by the Water Quality Management Office. BOI, 2008. “Industrial Estates: Zone 1”, Available online: http://www.boi.go.th/english/how/industrial_estates_zone1.asp. Crown, 2004. “Sea Level Rise and Storm Surge”, Met. Office, Hadley Centre for Climate Prediction and Research. R-1 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report References CSIRO, 2006. “Climate Change in the Asia/Pacific Region”, a consultancy report prepared for the Climate and Development Roundtable. CU, 2007. “Standard Urban Planning of Bangkok Report” prepared by the Architectural Department DDC, 2007 “Infection Diseases Record in Bangkok 2003-2007” prepared by Bureau of Epidemiology. DDPM, 2005. “Master Plan for Flood, Windstorm and Mudslide Hazards Prevention, Mitigation and Recovery Services in Emergency Period” DDPM, 2009. ”Master Plan of Earthquake and Landslide Protection and Mitigation”, Progress Report. DEDE, 2006. “Oil in Thailand”, Annual Report 2006. Department of Survey and Mapping, 2001. “A Country Report on the Geodetic and Tidal Activities th in Malaysia”, 7 GLOSS meeting. DGR, 1998. “Groundwater Crisis and Land Subsidence in Bangkok and Its Vicinity, Mitigation of Groundwater Crisis and Land Subsidence in Bangkok Project”. DGR, 2003. “Effects of Groundwater Over-Pumping Mitigation: Mathematic Model Study”. DGR, 2007. “Groundwater and Land Subsidence Situation and Groundwater Management in Bangkok and Adjacent Area”. Ding, X., Zheng D, Wong, W.T., Li. K.W., Chen, W. and Zhong, P, 2004. “Recent Sea Level Variations in Southern China from Tide Gauge Observation”, proceedings of the Asia- Pacific Space Geodynamics Symposium, p.126-136. DIW, 2008. “Industrial Zones”, Available online: http://www.diw.go.th/diw_web/html/versionthai/data/liz.asp. DOEB, 2008 “Energy Consumption”, Available online: http//www.doeb.go.th DOPA, 2007 “Number of Household”, Available online: http://www.dopa.go.th/stat/sumyear.html. DOPA, 2008a “Number of Population”, Available online: http://www.dopa.go.th/stat/sumyear.htm DOPA, 2008b “Administration of Thailand”, Available online: http://www.dopa.go.th/padmic/jungwad76/jungwad76.htm DPT, 2006. “Bangkok and Vicinities Plan Project, Final Report”, prepared by the Consultant of Technology Co. Ltd and TEAM Consulting Engineering and Management Co. Ltd. DPT, 2007. ”Bangkok and Vicinities Regional Plan B.E.2600”. Dutta, D. and M.S. Babel (ed), 2005. “Floods in Coastal Cities under Climate Change Conditions, Proceedings of the International Symposium”, Organized by the Asian Institute of Technology and Asia Pacific Network for Global Change Research. ECLAC, 2003. “Handbook for Estimating the Socio-economic and Environmental Effects of Disasters”. Ericson, J.P. C.J. Vorosmarty, S.L. Dingman, L.G. Ward and M. Maybeck, 2006. “Effective Sea Level Rise and Deltas: Causes of Change and Human Dimension Implications”, Global Planet Change, p.63-82. I-EA-T, 2008. “Industrial estates, Region, Zones”, Available online: http://www.ieat.go.th/view_static.php?lang=th&view=width&content=indusdata. IPCC, 2007. "Impacts, Adaptation and Vulnerability", Working Group II Report. IPCC AR4, 2007. “Synthesis Report; Summary for Policymakers”. JBIC, 2008. “Interim Report, Study on Climate Impact Adaptation and Mitigation in Asian Coastal Mega Cities” prepared by the Integrated Research System for Sustainability Science, University of Tokyo. JICA, 1995. “The Study on Management of Groundwater and Land Subsidence in the Bangkok Metropolitan Area and Its Vicinity”. Litchfield Whiting Bowne and Associate, 1960. “Land Use Monograph, Greater Bangkok Plan”. MEA, 2007. “Power System Planning Section”, Master Plan on Replacement of Overhead Cables by Underground Cables, 2008-2022. Milliman, J.D., C. Rutkowski, and M. Meybeck, 1995. “River Discharge to the Sea: A Global River Index”, LOICZ reports and studies: LOICZ Core Project Office, 125 pp. R-2 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report References MOEN, 2008 “Organization Chart of Ministry of Energy”, Available online: http://www.energy.go.th/moen/Index.aspx?MenuID=20 MOI, 2008 “Organization Chart of Ministry of Interior”, Available online: http://www.moi.go.th/portal/page?_pageid=33,76239&_dad=portal&_schema=PORTAL MONRE, 2005a. “Solid Waste Management Monitoring for Local Municipal under Regional Environmental Office 5 (Nakhon Pathom)” prepared by the Regional Environmental Office 5. MONRE, 2005b. “Solid Waste Management Monitoring for Local Municipal under Regional Environmental Office 6 (Nonthaburi)” prepared by the Regional Environmental Office 6. MONRE, 2006a. “The Environment Annual Report 2007” prepared by the Regional Environmental Office 6. MONRE, 2006b. “The Efficiency Monitoring of Local Municipal Wastewater Treatment Plant under Regional Environmental Office 5 (Nakhon Pathom)” prepared by the Regional Environmental Office 5. MONRE, 2007. “The Efficiency Monitoring of Local Municipal Wastewater Treatment Plant under Regional Environmental Office 6 (Nonthaburi)” prepared by the Regional Environmental Office 6. MONRE, 2008a. “Solid Waste Management in Nakhon Pathom Province”, Available online: http://wwwo.reo05monre.com/main_menu/data_base_environment/junk_nk.thm MONRE, 2008b. “Solid Waste Management in Samut Sakhon Province”, Available online: http://wwwo.reo05monre.com/main_menu/data_base_environment/junk_sk.thm. MONRE, 2008c. “Water Pollution of Samut Prakan Province”, Available online: http://wwwo.geocities.com/mnre_reo6/samutprakan/water_pollution _samutprakan.htm. MOPH, 2008. “Annual Report of Diseases in Thailand”, Available online: http://203.157.15.4/Annual/Total_Annual.html. MWA, 2008a. “The 8th Bangkok Water Supply Improvement Project”. Available online: http://www.mwa.co.th/download/invest_p8_july51.pdf MWA, 2008b. “The Annual Report 2007”, Available online: http://www.mwa.co.th/download/pln01/pp_web_50/index.html MWA, 2008c. “The Water Production”, Available online http://www.mwa.co.th/produce.html MWA, 2008d. “The Summary Information of Water Supply System”. NEPC, 2007. “Load Forecast Report”. NESDB, 2007a. “Poverty Line”. NESDB, 2007b. “Gross Regional and Provincial Products” Available online: http://www.nesdb.go.th/Portals/0/eco_datas/account/gpp/2007/TABLE%20IN%20GPP%2 0BOOK%202007.zip NESDB, 2007c. “Population Projections for Thailand 2003–2030”. Nguyen The Tuong, 2004. “Sea Level Measurement and Sea Level Rise in Vietnam”, GLOSS training course, Malaysia. NSO, 2006 “Business Trade and Services Survey” NSO, 2007 “Industrial Census” Okubo, Y., A. Tanaka, and M. Kaku, 2000. “Role of Remote Sensing Survey for Environmental Change”, proceedings of the comprehensive assessments on impacts of sea level rise, Department of Mineral Resources, Thailand, p.20-27. OTP-IMAC, 2004. “The Intermodal Service Integration for the Improvement of Mobility, Accessibility, Sustainability and Livelihood for Bangkok Metropolitan Region (BMR) and Surrounding Area”. PWA, 2007a. “The Performance” Available online: http://reg2.pwa.co.th/PWA2_Data/M5.xls PWA, 2007b. “The Performance” Available online: http://reg3.pwa.co.th/PWA3_Data/M5.xls RID, 1999. “The Study on Integrated Plan for Food Mitigation in Chao Phraya River Basin” prepared by the CTI Engineering International Co., Ltd. in association with INA Corporation. RID, 2004. “The Study on Planning and Adaptation of Drainage Problem in Critical Area around Suvarnabhumi Airport Project” prepared by the Asia Institute of Technology in association with Kasetsart University and Thammasart University (report in Thai). R-3 Climate Change Impact and Adaptation Study for Bangkok Metropolitan Region Final Report References RID, 2006. “Improvement of Rivers and Drainage for Lower Chao Phraya East Bank to Divert to Bang Pakong and the Gulf of Thailand”. Rosner B., 2000. “Fundamentals of Biostatistics 5thed.” CA:Duxbury Thomson Learning. RTSD, 2007. “Land Subsidence Survey Report 2007”, Land Subsidence Survey in Bangkok and Adjacent Area Project, prepared by the Geodesy and Geophysics Division. Sabhasri, S. and Suwarnarat, K. 1996. “Sea Level Rise and Coastal Subsidence”, in Milliman, J. D. and Haq, B. U (eds.) p.343-356. Saito, Y., Y. Sato, Y. Suzuki, and S. Sinsakul, 2000a. “Late Holocene Chao Phraya Delta Progradation in the Central Plain of Thailand”, proceedings of the comprehensive assessments on impacts of sea level rise, Department of Mineral Resources. Saito Y., Y. Okubo, A. Tanaka, Y. Suzuki, Y. Sato, Y. Kinoshita, M. Tateishi, M. Umitsu and Y. Hirai, 2000b. “Study of Modeling of the Response and Influence of Sea Level Rise on Deltas and Coastal Lagoons”, Global Chang Research Fund Final Report on comprehensive assessment on impacts of sea level rise, Environment Agency of Japan, p.17-57. Somboon, J.R.P., 1992. “Holocene High Stand Shoreline of the Chao Phraya Delta, Thailand”, Journal of Southeast Asian Earth Sciences, vol. 7, p.53-60. Somboon, J.R.P. and Thiramongkol, N., 1993. “Effect of Sea Level Rise on the North Coast of the Right of Bangkok, Thailand”, Malaysian Journal of Tropical Geography, p. 3-12, 24. Sommart, N. and Itthi, T., 2007. “Sea Level Trend in the Gulf of Thailand Using Tide Gauge Data”, Faculty of Engineering, Chulalongkorn University. Sanchez-Arcilla, J.A. Jimenez and H.I. Valdemoro, 2006. “A Note on the Vulnerability of Deltaic Coasts”, application to the Ebro Delta, managing coastal vulnerability, Elsevier Science, Amsterdam, 282 pp. TRD, 2008 “The Assessment of Building and Construction during Legal Right Registration of Unmovable Asset, (B.E.2551-2554)” Umitsu, M., 2006. “Geo-environment and Effect of Sea Level Rise in the Chao Phraya Delta”, Department of Geography, Nagoya U. UNFCC, 2006. “Technologies for Adaptation to Climate Change”. Vongvisessomjai S., R. Polsi, C. Manotham, D. Srisaengthong, and S. Charulukkana, 1996. “Coastal Erosion in the Gulf of Thailand”, in J.D. Milliman and B.U. Haq, eds., Sea level Rise and Coastal Subsidence, Kluwer Academic Publ., Dordrecht, p.131-150. Watana, K., 2002. “A Recent Storm Surge Event in Thailand”, Available online: http://www.marine.tmd.go.th/paper/surge.html. Watana, K., Seree, S., and I-Ming, T., 2005. “Ocean Wave Forecasting in the Gulf of Thailand during Typhoon Linda 1997”, hard and soft computing approaches, J. Atmost and Ocean Sci., Vol. 10(3), p.145-161. WB, 1983. “Shadow Price for Economic Appraisal of Projection Thailand” prepared by Thailand/Indochina Division, East Asia and Pacific Program Department. WB, 2008. “Climate Resilient Cities, 2008 Primer, Reducing Vulnerabilities to Climate Change Impacts and Strengthening Disaster Risk Management in East Asian Cities” prepared by the East Asia and the Pacific Region Sustainable Development Department. Woodroffe, C.D., R.J. Nicholls, Y. Saito, Z. Chen and S.L. Goodbred, 2006. “Landscape Variability and the Response of Asian Mega-deltas to Environmental Change”, Global Change and Integrated Coastal Management: The Asia-Pacific Regions, N. Harvey, Ed. Springer, New York. R-4