Public Disclosure Authorized Public Disclosure Authorized Public Disclosure Authorized Public Disclosure Authorized The World Bank Flood Risk Assessment for the Ganges Basin in South Asia For the attention of: Dr. Bill Young Lead Water Resources Specialist South Asia Water Initiative The World Bank, The Hindustan Times House (Press Block) 18-20, Kasturba Gandhi Marg New Delhi - 110001 Email: [email protected] Company Information: Name RMSI Private Limited CIN U74899DL1992PTC047149 Registered Office Address Seating 3, Unit No. 119, First Floor, Vardhman Star Citi Mall, Sector-7, Dwarka New Delhi Delhi-110075 India Corporate Office Address A-8, Sector-16 Noida, 201 301 India Tel:+91 120 251 1102, 251 2101 Fax:+91 120 251 1109, 251 0963 E-mail: [email protected] Contact: RMSI Private Limited A-8, Sector 16 Noida 201301, India Tel: +91-120-251-1102, 2101 Fax: +91-120-251-1109, 0963 www.rmsi.com Email - [email protected] Final Report: Volume I Confidential Page 2 of 264 The World Bank Flood Risk Assessment for the Ganges Basin in South Asia Acknowledgements The Final Report (Volume-I and Volume –II) is an output of the South Asia Water Initiative (SAWI); a partnership between the World Bank and the governments of United Kingdom, Australia and Norway. The program is designed to support countries improve and deepen transboundary dialog, enhance the basin and water resources knowledge base, strengthen water institutions, and support investments that lead to sustainable, fair and inclusive development of the Himalayan Rivers. RMSI is thankful to Dr. Bill Young, Lead Water Resources Specialist, World Bank, Washington DC for the continuous support provided throughout the project. We are thankful for the support and suggestions provided by Dr. Satya Priya, Senior Water Resources Specialist, World Bank, New Delhi. Important contributions were made by Dr. Anju Gaur, Senior Water Resources Specialist World Bank, New Delhi. The core team immensely benefitted from the advice of World Bank consultants Dr Raj Chabungbam, Dr Debashish Goswami and Ms Priyanka Chaturvedi. The work was led by Dr. MVRL Murthy, Vice President, RMSI Private Limited. The core team included Pratul Srivastava, Ankit Avasthi, Deshraj Singh, Sanwar Bajiya, Divyanshi Agarwal, and Sumit Dhand of RMSI Private Limited. We would also like to extend our sincere gratitude to various institutions like Central Water Commission, India; Dartmouth Flood Observatory; Department of Hydrology and Meteorology, Nepal; India Meteorological Department; and Water Resource Information System of India (WRIS) whose various public source datasets, publications, and other information have been extensively used and referred in the report at various stages of the project. The team gratefully acknowledges support from the World Bank and SAWI and sincerely thanks all individuals and institutions met during the development of this work. Final Report: Volume I Confidential Page 3 of 264 The World Bank Flood Risk Assessment for the Ganges Basin in South Asia Table of Contents Acknowledgements ............................................................................................................... 3 Table of Contents .................................................................................................................. 4 List of Figures ....................................................................................................................... 8 List of Tables ...................................................................................................................... 16 Abbreviations Used ............................................................................................................. 21 Executive Summary ............................................................................................................ 22 1 Introduction .................................................................................................................. 29 1.1 Background........................................................................................................... 29 1.2 Topography........................................................................................................... 32 1.3 Climate ................................................................................................................. 32 1.4 Meteorological causes of heavy rainfall over Ganges River Basin ........................ 32 1.5 Rainfall pattern ...................................................................................................... 33 1.6 Objectives of the study .......................................................................................... 33 1.7 Scope of the study ................................................................................................ 34 1.8 About the fourth deliverable .................................................................................. 34 2 Exposure Data Collection and Management ................................................................ 36 2.1 Methodology for exposure data development ........................................................ 36 2.1.1 Data Collection .............................................................................................. 36 2.1.2 Data Processing And Data Gaps ................................................................... 36 2.1.3 Data Quality Checks And Quality Assurances ................................................ 37 2.1.4 Development Of Exposure Data And Generation Of Gis Data Layers ............ 38 2.2 Analysis of exposure elements ............................................................................. 38 2.2.1 Demographic Analysis ................................................................................... 38 2.2.2 Housing ......................................................................................................... 43 2.2.2.1 Overall Housing Occupancy.................................................................... 43 2.2.2.2 Residential houses ................................................................................. 46 2.2.2.3 Commercial houses ................................................................................ 49 2.2.2.4 Industrial Establishments ........................................................................ 52 2.2.2.5 Educational Institutions ........................................................................... 55 2.2.2.6 Health Facilities ...................................................................................... 58 2.2.2.7 Other houses .......................................................................................... 60 2.2.2.8 Housing Structural Types ........................................................................ 63 2.2.3 Infrastructure Data ......................................................................................... 64 2.2.3.1 Road Network ......................................................................................... 65 2.2.3.2 Rail Network ........................................................................................... 67 Final Report: Volume I Confidential Page 4 of 264 The World Bank Flood Risk Assessment for the Ganges Basin in South Asia 2.2.4 Agricultural Data ............................................................................................ 69 2.3 Estimation of exposure values .............................................................................. 77 2.3.1 Estimation Of Built-Up Area ........................................................................... 77 2.3.2 Calculation Of Total Housing Exposure Values .............................................. 80 2.3.3 Transportation ................................................................................................ 82 2.3.3.1 Roads ..................................................................................................... 82 2.3.3.2 Railways ................................................................................................. 84 2.3.4 Agriculture ..................................................................................................... 86 3 Flood Hazard Assessment ........................................................................................... 93 3.1 Methodology overview .......................................................................................... 93 3.2 Data availability ..................................................................................................... 93 3.2.1 Meteorological Data ....................................................................................... 93 3.2.2 Hydrological Data .......................................................................................... 95 3.2.3 Topographical Information ............................................................................. 97 3.2.4 Land Use Land Cover (LULC) ........................................................................ 98 3.2.5 Soil Map ......................................................................................................... 99 3.2.6 Flood History................................................................................................ 100 3.3 Basin and River Delineation ................................................................................ 106 3.4 Hydraulic modeling ............................................................................................. 107 3.4.1 Model Set Up ..............................................................................................