ANNUAL FLOOD REPORT 2014 FLOOD FORECASTING & WARNING CENTRE PROCESSING & FLOOD FORECASTING CIRCLE BANGLADESH WATER DEVELOPMENT BOARD Annual Flood Report 2014 Flood Forecasting and Warning Centre Bangladesh Water Development Board WAPDA Building Motijheel C/A Dhaka-1000 Phone : 9550755; 9553118 Fax : 9557386 Email ; [email protected] ; [email protected] Web : www.ffwc.gov.bd Compilation and Editing: Md. Amirul Hossain, Executive Engineer, FFWC, BWDB Contribution: Md. Sazzad Hossain, Sub-Divisional Engineer, FFWC, BWDB Md. Arifuzzaman Bhuyan, Sub-Divisional Engineer, FFWC, BWDB Ripon Karmaker, Assistant Engineer, FFWC, BWDB Review: Md. Mosaddeque Hossain, Superintending Engineer, PFFC, BWDB Published by the FFWC, BWDB, Ministry of Water Resources, Dhaka with financial assistance from the CDMP-II, Ministry of Disaster Management and Relief TABLE OF CONTENTS PREFACE ..........................................................................................................................iv Executive Summary ..........................................................................................................vi CHAPTER 1: INTRODUCTION .................................................................................... 1 1.1. THE PHYSICAL SETTING .................................................................................... 1 1.2. THE RIVER SYSTEM ............................................................................................ 1 1.3. ACTIVITIES OF FFWC .......................................................................................... 3 1.4. OPERATIONAL STAGES BEFORE FORECAST MODEL RUN ....................... 5 1.5. NATURE AND CAUSES OF FLOODING ............................................................ 6 1.5.1. CAUSATIVE FACTORS ................................................................................. 6 1.5.2. STATISTICS OF FLOODING ......................................................................... 7 CHAPTER 2 : RAINFALL SITUATION ....................................................................... 8 2.1 MAY ........................................................................................................................ 8 2.2 JUNE ........................................................................................................................ 9 2.3 JULY ...................................................................................................................... 11 2.4 AUGUST ............................................................................................................... 12 2.5 SEPTEMBER ......................................................................................................... 13 2.6 OCTOBER ............................................................................................................. 14 CHAPTER 3: RIVER SITUATION .......................................................................... 21 3.1 THE BRAHMAPUTRA BASIN ............................................................................. 21 3.2 THE GANGES BASIN .......................................................................................... 24 3.3 THE MEGHNA BASIN ........................................................................................ 26 3.4 THE SOUTH EASTERN HILL BASIN ............................................................... 29 3.5 RECORDED HIGHEST WATER LEVEL ........................................................... 31 CHAPTER 4: ................................................................................................................. 55 FLOOD FORECAST EVALUATION, 2014 ................................................................ 55 4.1 GENERAL ............................................................................................................. 55 4.2 EVALUATION CRITERIA OF FLOOD FORECAST PERFORMANCE .......... 56 4.2.1 MEAN ABSOLUTE ERROR (MAE) ........................................................... 56 4.2.2 CO-EFFICIENT OF DETERMINATION, R2 ............................................... 56 4.3 PRE-DEFINED SCALES TO EVALUATE FORECAST PERFORMANCE ..... 57 4.4 FORECAST STATISTICS AND MODEL PERFORMANCE, 2014 ................... 57 4.4.1 Deterministic forecast performance ...................................................................... 57 4.4.2 Medium Range (upto 10-days) Probabilistic Forecast Performance .................... 69 CHAPTER 5 : INUNDATION STATUS ...................................................................... 74 CHAPTER 6: RESEARCH AND DEVELOPMENT ................................................... 81 6.1 Development of Flash Flood Forecasting System ................................................... 81 6.2 Mobile Services for Early Warning ......................................................................... 82 6.3 JASON-2 Satellite Based Flood Forecast (Experimental) ....................................... 84 6.5 Comparison between FFWC and Satellite based Inundation Map .......................... 87 CHAPTER 7: CONCLUSIONS .................................................................................. 89 LIST OF TABLES Table 1. 1 :Year-wise Flood Affected Area in Bangladesh .................................................. 7 Table 2.1: Rainfall statistics for the monsoon 2014 over the four Basins ............................ 8 Table 2. 2 : Summary of the rainfall situation during the month of May 2014 .................... 9 Table 2. 3: Summary of the rainfall situation during the month of June 2014 ................... 10 Table 2. 4: Summary of the rainfall situation during the month of July 2014 .................... 11 Annual Flood Report 2014, FFWC, BWDB i Table 2. 5: Summary of the rainfall situation during the month of August 2014 ............... 12 Table 2. 6: Summary of the rainfall situation during the month of September 2014 ......... 13 Table 2. 7: Summary of Rainfall for the month of October-2014 ...................................... 14 Table 3. 1 : Comparison of WL 2014, 1988 & 1998 of few Stations Brahmaputra Basin. 23 Table 3.2 : Comparison of WL of 2014, 1988 & 1998 of few Stations in Ganges Basin. 26 Table 3. 3: Comparison of WL of 2014, 1988 & 1998 of few Stations in Meghna Basin. 29 Table 3. 4 : Comparison of WL of 2014, 1988 and 1998 of few Station in SE Hill Basin. 30 Table 3.5: Recorded Peak Water Level with Date during the monsoon 2014 .................... 31 Table 3. 6: Recorded Historical Highest Water Level with Date ....................................... 32 Table 4. 1 : Scales used for performance evaluation .......................................................... 57 Table 4. 2: Summary of forecast performance at 54 stations upto 5-days forecast - 2014 58 Table 4. 3 : Statistics for 24- hour forecast performance .................................................... 58 Table 4. 4 : Statistics for 48- hour forecast performance .................................................... 59 Table 4. 5 : Statistics for 72- hour forecast performance .................................................... 60 Table 4. 6 : Statistics for 96- hour forecast performance .................................................... 61 Table 4. 7 : Statistics for 120- hour forecast performance .................................................. 62 Table 4. 8 : Performance of 3-day Probabilistic Forecast ................................................... 69 Table 4. 9 : Performance of 5-day Probabilistic Forecast ................................................... 70 Table 4. 10 : Performance of 7-day Probabilistic Forecast ................................................. 71 Table 4. 11 : Performance of 10-day Probabilistic Forecast ............................................... 72 LIST OF FIGURES Figure 1 : Basin Map of Bangladesh with Water Level Gauge Stations ..........................viii Figure 2.1 : Isohyets of Actual Rainfall (May 2014) ........................................................ 15 Figure 2.2 : Isohyets of Actual Rainfall (June 2014) ........................................................ 16 Figure 2.3 : Isohyets of Actual Rainfall (July 2014) ......................................................... 17 Figure 2.4 : Isohyets of Actual Rainfall (August 2014) .................................................... 18 Figure 2.5 : Isohyets of Actual Rainfall (September 2014) ............................................... 19 Figure 2.6 : Isohyets of Actual Rainfall (October 2014) ................................................... 20 Figure 3.1 : Comparison of Hydrograph on Dharla at Kurigram ....................................... 34 Figure 3.2 : Comparison of Hydrograph on Teesta at Dalia ............................................... 34 Figure 3.3 : Comparison of Hydrograph on Ghagot at Gaibandha ..................................... 35 Figure 3.4 : Comparison of Hydrograph on Jamunesweri at Badargonj ............................ 35 Figure 3.5 : Comparison of Hydrograph on Punurbhoba at Dinajpur................................. 36 Figure 3.6 : Comparison of Hydrograph on Atrai at Mohadevpur ..................................... 36 Figure 3.7 : Comparison of Hydrograph on Brahmaputra at Noonkhawa .......................... 37 Figure 3.8 : Comparison of Hydrograph on Brahmaputra at Bahadurabad ........................ 37 Figure 3.9 : Comparison of Hydrograph on Jamuna at Serajgonj ...................................... 38 Figure 3.10 : Comparison of Hydrograph on Jamuna at Aricha ......................................... 38 Figure 3.11 : Comparison