REPORT submitted to Assam State Disaster Management Authority Department of Civil Engineering NIT Silchar, Assam July 2014 Flood Damage Mitigation: Report Working Group Principal Investigator : Parthasarathi Choudhury Professor, Department of Civil Engineering NIT Silchar, Silchar, Assam Email: [email protected] Team members : P.J. Roy, Assistant Professor, Department of Civil Engineering, NIT Silchar, Assam : J. Nongthombam, PhD student : Ms. N.Ullah, PhD student : Ms. Arti Devi, PhD student : Ms. S. Debbarman, PhD student Final Report-July- 2014: P. Choudhury-NIT Silchar, Assam i Flood Damage Mitigation: Report List of Figures: Figure Page Description No no 1.1 Ariel map of the study area 5 2.1 Main River Borak from Lakhipur to Bhanga (upto Bangladesh 11 Border) 2.2 Section Details of Barak River upto 500m countryside 15 2.3 Jiri Water shed 21 2.4 Cross sectional details of river Jiri 23 2.5 Ciri Water shed 24 2.6 Cross sectional details of river Ciri 26 2.7 Sonai Water shed 27 2.8 Cross sectional details of river Sonai 31 2.9 Badri Water shed 33 2.10 Cross sectional details of river Badri 35 2.11 Madhura Water shed 36 2.12 Cross sectional details of river Madhura 38 2.13 Jatinga Water shed 39 2.14 Cross sectional details of river Jatinga 41 2.15 Gagra Water shed 42 2.16 Cross sectional details of river Gagra 45 2.17 katakhal Water shed 47 2.18 Cross sectional details of river katakhal 51 2.19 Longai Water shed 52 2.20 Cross sectional details of river Longai 56 3.1 Grid Points Covering the Study Area 62 4.1 Flow chart for GIS application. 71 4.2 Digital Elevation Model of Jiri sub basin 72 4.3 Digital Elevation Model of Chiri sub basin 73 4.4 Digital Elevation Model of Madhura sub basin 74 4.5 Digital Elevation Model of Ghagra sub basin 75 4.6 Digital Elevation Model of Jatinga sub basin 76 4.7 Drainage network in Jiri sub catchment 78 4.8 Drainage network in Chiri sub catchment 79 4.9 Drainage network in Madhura sub catchment 80 4.10 Drainage network in Ghagra sub catchment 81 4.11 Drainage network in Jatinga sub catchment 82 4.12 Flow direction in Jatinga sub catchment 83 Final Report-July- 2014: P. Choudhury-NIT Silchar, Assam ii Flood Damage Mitigation: Report 4.13 Drainage network in Katakhal sub catchment 84 4.14 Drainage network in Sonai sub catchment 85 4.15 Slope map for Chiri sub catchment 86 4.16 Slope map for Jiri sub catchment 87 4.17 Slope map for Ghagra sub catchment 88 4.18 Slope map for Madhura sub catchment 89 4.19 Slope map for Jatinga sub catchment 90 4.20 Slope map for Katakhal sub catchment 91 4.21 Slope map for Sonai sub catchment 92 5.1 1st order watersheds for Madhura 96 5.2 2nd Order sub-watersheds for Madhura. 97 5.3 2nd Order sub-watersheds for Madhura. 98 5.4 3rd Order sub-watersheds for Madhura 99 5.5 4th Order sub-watersheds for Madhura. 100 5.6 5th Order sub-watersheds for Madhura. 101 5.7 Madhura watershed (6th Order). 102 5.8 1st Order sub-watersheds for Ghagra. 103 5.9 2nd order sub-watersheds for Ghagra. 104 5.10 3rd Order sub-watersheds for Ghagra 105 5.11 4th Order sub-watersheds for Ghagra. 106 5.12 5th order sub-watersheds for Ghagra. 107 5.13 Ghagra watershed (6th order). 108 5.14 Selected sub-watersheds for Madhura. 109 5.15 Selected sub-watersheds for Ghagra. 110 1 111 5.16 Estimation of ratios RRAB, and RL for MSW5 2 111 5.17 Estimation of ratios and for MSW5 . 3 112 5.18 Estimation of ratios and for MSW5 . 1 112 5.19 Estimation of ratios and for MSW3 . 1 113 5.20 Estimation of ratios and forGSW5 2 113 5.21 Estimation of ratios and forGSW5 . 1 114 5.22 Estimation of ratios and forGSW4 2 114 5.23 Estimation of ratios and forGSW4 . 1 115 5.24 Estimation of ratios and forGSW3 2 115 5.25 Estimation of ratios and forGSW3 . 3 116 5.26 Figure 5.26: Estimation of ratios and forGSW3 . Final Report-July- 2014: P. Choudhury-NIT Silchar, Assam iii Flood Damage Mitigation: Report 5.27 4 116 Estimation of ratios and forGSW3 . 5.28 1hr UH for Madhura sub-watershed . 120 5.29 1hr UH for Madhura sub-watershed . 120 5.30 3 121 1hr UH for Madhura sub-watershed MSW5 . 5.31 1 121 1hr UH for Madhura sub-watershed MSW3 . 5.32 1 122 1hr UH for Ghagra sub-watershedGSW5 . 5.33 1hr UH for Ghagra sub-watershed . 122 5.34 1hr UH for Ghagra sub-watershed . 123 5.35 1hr UH for Ghagra sub-watershed . 123 5.36 1 124 1hr UH for Ghagra sub-watershedGSW3 . 5.37 1hr UH for Ghagra sub-watershed . 124 5.38 1hr UH for Ghagra sub-watershed . 125 5.39 1hr UH for Ghagra sub-watershed . 125 5.40 1hr UH for Machura watershed. 130 5.41 1hr UH for Ghagra watershed 130 5.42 1hr UH ordinates for Chiri subbasin 132 5.43 1hr UH ordinates for Jiri subbasin 135 5.44 1hr UH ordinates for Jhatinga subbasin 138 5.45 1hr UH ordinates for Sonai Subbasin 140 5.46 1hr UH ordinates for Katakhal subbasin 144 6.1 represents the flood event from 10th – 17th1 July, 2004 at 148 RRAB, RL MSW5 BpGhat. MSW 2 6.2 Represents the flood event from 19th – 295th July, 2004 at 148 BpGhat 6.3 The flood event from 11th – 21st June, 2006 at BpGhat. 148 6.4 Observed and simulated discharge at Annapurnaghat (event-1) 150 6.5 Observed and simulated discharge at Annapurnaghat (event-2) 150 6.6 Observed and simulated discharge at Annapurnaghat2 (event-3) 151 GSW5 6.7 Observed and simulated discharge at Badrpurghat1 (event-1) 151 GSW4 6.8 Observed and simulated discharge at Badrpurghat (event-2) 152 2 6.9 Observed and simulated discharge atGSW Badrpurghat4 (event-3) 152 6.10 Flow at Annapurnaghat: observed flow , safe flow and flow by 167 regulating upstream ungauged catchments2 flows from Jiri, Chiri and Madhura GSW3 3 GSW3 Final Report-July- 2014: P. Choudhury-NIT Silchar, Assam iv Flood Damage Mitigation: Report 6.11 Flow at Badarpurghat: observed flow, safe flow and flow by 168 regulating upstream ungauged catchments flows from Jiri, Chiri , Madhura, Jatinga & Ghagra 6.12 Flow at Annapurna Ghat (Event-1) including and not including 173 effects of climate change: U/S flow regulation-all catchment 6.13 Flow at Annapurna Ghat (Event-2) including and not including 174 effects of climate change: U/S flow regulation-all catchment 6.14 Flow at Annapurna Ghat (Event-3) including and not including 175 effects of climate change: U/S flow regulation-all catchment 6.15 Flow at Badarpur Ghat (Event-1) including and not including 176 effects of climate change: U/S flow regulation-all catchment 6.16 Flow at Badarpur Ghat (Event-2) including and not including 177 effects of climate change: U/S flow regulation-all catchment 6.17 Flow at Badarpur Ghat (Event-3) including and not including 178 effects of climate change: U/S flow regulation-all catchment 7.1 Observed Sediment Concentration & simulated sediment 181 concentration in upper network 7.2 Sediment Concentration at AP Ghat for no sediment flow from 181 Dholai catchments 7.3 Observed Sediment and simulated sediment discharge at AP 182 Ghat in upper network 7.4 Sediment Discharge at Annapurnaghat for no sediment flow 182 from from Dholai 7.5 sediment concentration for no sediment flow from Dholai 184 7.6 Sediment concentration for no sediment flow from Madhura, 184 7.7 Observed sediment concentration and concentration at 185 BPghat for no sediment flow from Dholai and Madhura subcatchments 7.8 Sediment dischargefor no sediment flow from Matijuri 185 7.9 Sediment discharge for no sediment flow from Matijuri and 186 Dholai subcatcments. 8.1 Observed, estimated and 2 hours ahead forecasts of 191 downstream flow rates at Badarpurghat 8.2 Observed, estimated and 2 hours ahead forecasts of 191 downstream flow top width at Badarpurghat . Final Report-July- 2014: P. Choudhury-NIT Silchar, Assam v Flood Damage Mitigation: Report List of Tables: Table No Particulars Page no 1.1 Details of Major Tributaries of River Barak in the study area 4 2.1 Flow area Details of Barak River system 12 2.2 Flow area Details of Jiri River system 22 2.3 Flow area Details of Ciri River system 25 2.4 Flow area Details of Sonai River system 28 2.5 Flow area Details of Badri River system 34 2.6 Flow area Details of Madhura River system 37 2.7 Flow area Details of jatinga River system 40 2.8 Flow area Details of Gagra River system 43 2.9 Flow area Details of Katakhal River system 48 2.10 Flow area Details of Longai River system 53 2.11 Details of existing embankment in the study area 59 2.12 Details of existing major sluice gates in Barak Valley 60 3.1 Rainfall gauging station in the selected Grids 63 3.2 Estimated T-year rainfall intensity for Barak Valley 67 3.3 Estimation of mean rainfall using regional mean relationship 68 4.1 Table-4.1 basins in the Study Area 93 5.1 Geomorphologic characteristics of sub watersheds of Ghagra 117 and Madhura 5.2 Morphological parameters for the subcatchments 117 5.3 3 118 1hr UH ordinates for MSW5 .