44167-012: Main River Flood and Bank Erosion Risk Management Program

304 Pages·2014·17.34 MB·English

Technical Assistance Consultant’s Report

Project Number: 44167-012
December 2013

Bangladesh: Main River Flood and Bank Erosion Risk
Management Program
(Financed by the Japan Fund for Poverty Reduction)

Prepared by Northwest Hydraulic Consultants, Canada

In association with Resource Planning and Management Consultants Ltd., Bangladesh

For Bangladesh Water Development Board

This consultant’s report does not necessarily reflect the views of ADB or the Government concerned, and
ADB and the Government cannot be held liable for its contents. (For project preparatory technical
assistance: All the views expressed herein may not be incorporated into the proposed project’s design.
Government of the People's Republic of Bangladesh

Bangladesh Water
Development Board

Aricha
1967 1973 1987 1992 202052??5?

Project Preparatory Technical Assistance No. 8054 BAN

Main River Flood and Bank Erosion
Risk Management Program

Final Report, Annex E
River and Charland Morphology and River Engineering

December 2013

In association with

Resource Planning
& Management
Consultants Ltd.
Asian Development Bank
Funded by the Japan Fund for Poverty Reduction

Government of the People’s Republic of Bangladesh
Bangladesh Water Development Board

Project Preparatory Technical Assistance 8054 BAN
Main River Flood and Bank Erosion
Risk Management Program

Final Report, Annex E
River and Charland Morphology and River Engineering

December 2013
PPTA 8054-BAN: Main River Flood and Bank Erosion Risk Management Program

Document Background
Title: River and Charland Morphology and River Engineering,
Annex E
Principal Author: Gerrit Klaassen
Contributions: CEGIS, Appendix E1
Md. Motiur Rahman Jewel, Appendix E2
Final version: August 2013

Document Development

R1, 07 July 2013 Formatting, spell check, font change,
Revision for justification, Inserted Sec. 2.3, 3, 4.7, 4.8
Final R1, 21 July 2013 Formatting, spell check, font change,
justification, Inserted Sec. 6
R2, 23 July 2013 Formatting, spell check, font change,
justification
R3, 29 July 2013 Formatting, spell check, font change,
justification, Inserted Sec. 8
R4, 30 July 2013 Formatting, spell check, font change,
justification, Inserted Sec. 8
R5, 31 July 2013 Page setup and print
R6, 13 Sept. 2013 Reviewed by Gerrit Klaassen
R7, 14 Sept. 2013 Formatting
R8, 18 Sept. 2013 Formatting (Added Annex-E3)
R9, 21 Sept. 2013 Formatting (Twice Chapter 7, one deleted)
R10, 25 Sept. 2013 Added Chapter 5
R11, 30 Sept. 2013 Added Annexure E3
R12, 01 Oct. 2013 Added Chapter 8
R13, 02 Oct. 2013 Reviewed by Gerrit Klaassen
R14,21 Nov.2013 Reviewed by Gerrit Klaassen
R15, 12 Dec. 2013 Replaced Photographs Sec. 1
R16, 21 Dec. 2013 Page setup and changed month name
R17, 28 Feb. 2014 Reprinted R16
Review by : ko, 1 August, 2013
ko, 15 October, 2013

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River and Charland Morphology and River Engineering

MAIN REPORT

ANNEXES

Annex A Priority Sub-reach Selection & Sub-reach Descriptions
Annex A1 Priority Sub-reach Selection
Annex A2 Sub-reach Description
Annex B Background Data
Annex B1 National Water Resources Database
Annex B2 Socio-economic Data
Annex B3 Surveys and Field Visits
Annex C Institutional and Financial Assessment
Annex D Hydrology and Flood Modelling
Annex E River and Charland Morphology and River Engineering
Annex F Design Issues
Annex F1 Geotechnical Investigations
Annex F2 Technical Designs
Annex G Economic Feasibility
Annex G1 Project Cost
Annex G2 Economic Assessment
Annex H Implementation and Procurement Planning
Annex I Social Gender Equity Strategy & Action Plan
Annex J Environmental Impact Assessment
Annex K Involuntary Resettlement
Annex K1 Resettlement Framework
Annex K2 Resettlement Plan

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River and Charland Morphology and River Engineering

Table of Contents

1 Introduction ..................................................................................................................... 1
2 River morphology Jamuna and Padma ............................................................................. 5
2.1 River characteristics .................................................................................................................. 5
2.2 Past bank erosion and accretion Jamuna and Padma River ...................................................... 8
2.3 Impact of past widening on char and floodplain area ............................................................. 15
3 Char land Morphology .................................................................................................... 19
3.1 Introduction ............................................................................................................................ 19
3.2 Char dynamics ......................................................................................................................... 22
3.3 Char and Vegetation Development Over Time ....................................................................... 26
3.4 Char level increase, cross-profiles and soil development........................................................ 28
3.5 Vegetation development ........................................................................................................ 33
3.6 Discussion ............................................................................................................................... 36
4 Future Planforms relevant for Programme Development ............................................... 38
4.1 Introduction ............................................................................................................................ 38
4.2 Planform characteristics of the Jamuna and Padma Rivers ..................................................... 39
4.3 Important criteria for future stabilized planforms .................................................................. 42
4.4 Earlier proposals for stabilization of the Jamuna and Padma Rivers ....................................... 44
4.5 Possible stabilized planforms for Lower Jamuna and Upper Padma ....................................... 51
4.6 Some reflections on implementation ...................................................................................... 57
4.7 Physical Limitations to Land Recovery .................................................................................... 58
4.8 Possible physical impact of land recovery ............................................................................... 67
5 Tranche 1 RBP Works ..................................................................................................... 74
5.1 Introduction ............................................................................................................................ 74
5.2 Lower Jamuna River ................................................................................................................ 75
5.2.1 Morphological Considerations .................................................................................... 75
5.2.2 Proposed RBP Works .................................................................................................. 80
5.2.3 Design boundary conditions RBP works ...................................................................... 80
5.2.4 Possible Impact JRB 1/2 and RLB 1/2 .......................................................................... 84
Under tranche 1 also 2 km of RBP works are planned at Zaffarganj. It is expected that the
impact of the latter works will be minor. .................................................................... 86
5.3 Padma River ............................................................................................................................ 86
5.3.1 Morphological Considerations .................................................................................... 86
5.3.2 Proposed RBP works ................................................................................................... 90
5.3.3 Design boundary conditions ....................................................................................... 91
5.3.4 Possible impact ........................................................................................................... 92
6 Tranche 1 Land recovery pilot projects ........................................................................... 93
6.1 Introduction ............................................................................................................................ 93
6.2 Proposed approach for land recovery ..................................................................................... 94
6.3 Questions to be answered with the pilot projects .................................................................. 97
6.4 Testing of fertilization and soil formation concepts .............................................................. 100
6.5 Testing of stabilization techniques for chars ......................................................................... 100
6.6 Testing of methods to accelerate deposition on chars ........................................................ 102
6.7 Set-up and design of pilot projects ....................................................................................... 102
6.8 Time Schedule and Costs ...................................................................................................... 109
7 River Stabilization and Integrated River Development Plan ........................................... 112
7.1 Introduction .......................................................................................................................... 112
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7.2 Purpose of Brahmaputra Integrated Development Plan and Brahmaputra Stabilization Plan
.............................................................................................................................................. 113
7.3 Scope of the Brahmaputra Integrated Development Plan .................................................... 114
7.4 How to develop the Brahmaputra Integrated Development Plan? ....................................... 117
7.5 Technical issues to address in the Brahmaputra Integrated Development Plan ................... 118
7.6 Supporting studies ................................................................................................................ 120
7.7 Proposed Plan preparation ................................................................................................... 124
7.8 Institutional arrangements for plan development ................................................................ 127
8 Possible Tranche 2 & Tranche 3 sub-projects .................................................................1 29
8.1 Introduction .......................................................................................................................... 129
8.2 Lower Jamuna River .............................................................................................................. 130
8.3 Upper Padma River ............................................................................................................... 133
8.4 Lower Padma River and Padma-Meghna confluence ............................................................ 135
8.5 Supporting morphological studies ........................................................................................ 138
9 Possible Improvements Bank Erosion Prediction ...........................................................1 40
9.1 Introduction .......................................................................................................................... 140
9.2 Possible improvements ......................................................................................................... 141
9.3 How to improve predictions and dissemination? .................................................................. 143
9.4 Set-up of study to improve bank erosion predictions ........................................................... 146
9.5 Time schedule, staffing and costs ......................................................................................... 147
References ..........................................................................................................................1 51

Appendix E1 Study of Charland Processes in the Jamuna River ………………………. 153
Appendix E2 Exploring Hydraulic Study into Land Recovery …………………………... 232
Appendix E3 On the use of catkin and vetiver for building with nature ………….. 278

List of Tables

Table 2-1: List of satellite images used in this study with acquisition date .............................................. 17
Table 3-1: Char age (Source: EGIS, 2000) ................................................................................................. 22
Table 3-2: Thickness of upper layer of silt and clay as observed in the cross-profiles of the excavated
holes in the studied chars ........................................................................................................................ 32
Table 4-1: Characteristic dimensions of possible planforms for different assumptions for number of
parallel channels ...................................................................................................................................... 52
Table 4-2: Preliminary assessment of future stabilized planform for the Lower Jamuna ........................ 56
Table 4-3: Preliminary assessment of future stabilized planform for the Upper Padma ......................... 57
Table 5-1: Multiplication factors to determine scour depth .................................................................... 84
Table 6-1: Services to be provided for char stabilization pilot works ..................................................... 111
Table 7-1: Functions and interests to consider in the proposed study .................................................. 116
Table 7-2: Overview of possible supporting studies during preparation and implementation of BIDP . 121
Table 7-3: Tentative estimate of costs supporting studies..................................................................... 123
Table 7-4: Tentative inputs of international and national experts ......................................................... 126
Table 7-5: Time schedule and phasing of proposed project to develop the Brahmaputra Integrated
Development Plan and River Stabilization plan ..................................................................................... 127
Table 7-6: Cost estimate of proposed study for the development of the BIDP...................................... 127
Table 9-1: Possible additional data collection to improve predictions .................................................. 145

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Table 9-2: Proposed professional staff input study into improvement of the prediction of bank erosion
............................................................................................................................................................... 149
Table 9-3: Proposed professional staff input for the study into improvement of the prediction of bank
erosion ................................................................................................................................................... 149
Table 9-4: Professional input for improvement of prediction bank erosion in Tranches 1 and 2 .......... 150

List of Figures

Figure 2-1: Summary of some characteristics of the main rivers of Bangladesh (FAP 24, 1996) ............... 6
Figure 2-2: Natural controls on the planform of the Ganges River (EGIS, 2003) ....................................... 7
Figure 2-3: Overall erosion and accretion of the Brahmaputra/Jamuna River in the period 1973-2010 ... 9
Figure 2-4: Overall erosion and accretion of the Brahmaputra/Jamuna River in the period 2007-2012 . 10
Figure 2-5: Overall erosion and accretion of the Padma River in the period 1973-2009 ......................... 11
Figure 2-6: Overall erosion and accretion of the Padma River in the period 2004-2009 ......................... 12
Figure 2-7: Widening of Brahmaputra/Jamuna (top) and Padma (below) ............................................... 13
Figure 2-8: Number of embankment retirements along the Brahmaputra/Jamuna right bank).............. 14
Figure 2-9: Predicted widening of the Brahmaputra/Jamuna for the period 2006 to 2020 (CEGIS, 2007)
................................................................................................................................................................. 15
Figure 2-10: Increase in average width of the Lower Jamuna River over the period 1973- 2010 ............ 16
Figure 2-11: Area of water, sandy and vegetated char land in the Jamuna River between the Jamuna
Bridge and the confluence with the Ganges River ................................................................................... 18
Figure 3-1: Brahmaputra/Jamuna River (left) with reach studied (right) and selected chars indicated by
pink lines .................................................................................................................................................. 21
Figure 3-2: Char dynamics in Brahmaputra-Jamuna River in period 1973-2000: incidence of chars (left,
age of chars (middle) and char persistence (right) (EGIS, 2000) .............................................................. 24
Figure 3-3: Age of chars in the study reach .............................................................................................. 25
Figure 3-4: Char elevation as function of char age (EGIS, 1997)) ............................................................. 25
Figure 3-5: Examples of the development of chars .................................................................................. 27
Figure 3-6: Development of vegetation cover of Chauhali char over time .............................................. 28
Figure 3-7: Measured topography of the three selected chars derived from relative char level ............. 29
Figure 3-8: Relative char level versus age of char according to EGIS & Delft Hydraulics (1997) and the
present study ........................................................................................................................................... 30
Figure 3-9: Location and excavation of holes for cross-profiling of upper 2m of chars ........................... 31
Figure 3-10: Example of cross-profile (Char Pachakhola, Bera, Pabna) .................................................... 32
Figure 3-11: Thickness of upper silt and clay layer as function of relative elevation of char ................... 33
Figure 3-12: Ages of vegetation in study area .......................................................................................... 34
Figure 3-13: Increase of vegetation coverage with age of chars .............................................................. 35
Figure 3-14: Stages of floodplain soil formation (FAP 19 & FAP 16, 1995) ............................................... 37
Figure 4-1: Changes of the Jamuna/Brahmaputra River over the last decades (CEGIS, 2012a) ............... 41
Figure 4-2: Changes of the Padma River over the last decades (CEGIS, 2012b) ....................................... 42
Figure 4-3: Existing bank protection works along the Brahmaputra/Jamuna River (CEGIS, 2012a) ........ 44
Figure 4-4: Alternatives for river training of the Jamuna River as proposed by China Bangladesh Joint
Expert Team (1991) ................................................................................................................................. 46
Figure 4-5: Tentative planforms suggested by FAP-1 (1994) for long term river training ........................ 47
Figure 4-6: Outline of the stabilized planform of the Jamuna River as proposed by CEGIS (2012a) ........ 49
Figure 4-7: Provision for maintaining riverine ecosystem (CEGIS, 2012a) ............................................... 49
Figure 4-8: Outline of the stabilized planform of the Padma River as proposed by CEGIS (2012b) ......... 50
Figure 4-9: Empirical design rules Yellow River (Wu Boasheng et al, 2005) ............................................ 51
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Figure 4-10: Alternatives LJ-1A through C: single channel bend control plans for the Lower Jamuna River
................................................................................................................................................................. 54
Figure 4-11: Alternative LJ-1.5A and B and LJ-2A and B: multiple channel solutions with combined bend
and node control stabilization plans for the Lower Jamuna River ........................................................... 55
Figure 4-12: Alternative bend and node control stabilization plans for the Upper Padma River ............. 56
Figure 4-13: Simplified cross section showing the river training works, dreding and subsequent filling
(CEGIS, 2012a) ......................................................................................................................................... 58
Figure 4-14: Reduction of river and floodplain width ............................................................................. 59
Figure 4-15: Regime equations for the width of Jamuna channels ......................................................... 60
Figure 4-16: Some details on 1D hydraulic model of the Lower Jamuna River ....................................... 61
Figure 4-17: Simulations carried out ....................................................................................................... 62
Figure 4-18: Change in flow through main channel due to recovery of some lost floodplain land ......... 63
Figure 4-19: Initial effect of recovery of some lost floodplain land on water levels, velocities and
sediment transport for 20 year flood (along Jamuna Left Channel) ........................................................ 64
Figure 4-20: Initial effect of recovery of some lost floodplain land on water levels, velocities and
sediment transport for 20 year flood (along Jamuna Right Channel) ...................................................... 65
Figure 4-21: Local constriction into a river channel ................................................................................. 66
Figure 4-22: Increase in average water depth due to constriction.......................................................... 67
Figure 4-23: Increase in slope of an alluvial river system as a function of the braiding index for different
assumptions for the prediction of the bankful discharge (see Box 4-2) .................................................. 71
Figure 4-24: Two schematized cross-sections developed on the basis of 9 cross-sections of the Jamuna
Main Channel (for details see Appendix E2) ............................................................................................ 72
Figure 4-25: Effect of schematization cross-section on water levels, velocities and sediment transport
along Jamuna Left Channel for 20 year flood after closing right channel ................................................ 74
Figure 5-1 Lower Jamuna River downstream of Bangabandhu bridge ..................................................... 75
Figure 5-2 Jamuna River with reach affected by the Bangabandhu Bridge RTW shown in greenish box . 76
Figure 5-3 Changes in low-water channel of the Lower Jamuna River (Sarker et al, 2011)...................... 76
Figure 5-4 Bank erosion along right bank and left bank of the Lower Jamuna River ............................... 77
Figure 5-5 Predicted bank erosion along the Lower Jamuna River at Chauhali for the monsoon 2013
(CEGIS, 2013) ........................................................................................................................................... 78
Figure 5-6 Predicted bank erosion along the Lower Jamuna River at Zaffarganj for the monsoon 2013
(CEGIS, 2013) ........................................................................................................................................... 79
Figure 5-7 Proposed Tranche 1 River Bank Protection works along the Lower Jamuna River ................. 81
Figure 5-8 Relative discharge as function of braiding parameter k and safety factor (FAP21/22) ........... 82
Figure 5-9 Relative discharge as function of braiding parameter k and resulting safety factor (based on
data from the Brahmaputra River in Assam) ........................................................................................... 83
Figure 5-10 Variation of average velocities along right and left channel of Lower Jamuna River for three
floods in present condition ...................................................................................................................... 85
Figure 5-11 Predicted downstream impact of bank erosion and bank protection near Chauhali
(source: CEGIS)......................................................................................................................................... 86
Figure 5-12: Geomorphology of the area through which the Padma flows ............................................. 88
Figure 5-13: Padma planform with more resistant clayey banks (i) along the Northern bank between
Dhulrirum and Mawa and (ii) along the Southern bank near Sureswar ................................................... 88
Figure 5-14: Planform changes Upper Padma River in period 1963-2008 ............................................... 89
Figure 5-15: Changes of Northern bankline of Upper Padma River near Harirampur ............................. 89
Figure 5-16: Channel incidence map of the Padma River......................................................................... 90
Figure 5-17: Predicted bank erosion during the 2013 monsoon of the Upper Padma River near
Harirampur (source CEGIS) ...................................................................................................................... 90
Figure 5-18 Proposed RBP works along the Northern bank of the Upper Padma River near Harirampur 91

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