Study on Surface Water Availability for Future Water Demand for Dhaka City

STUDY ON SURFACE WATER AVAILABILITY FOR FUTURE WATER DEMAND FOR DHAKA CITY

MD EHSANUL HAQUE

DOCTOR OF PHILOSOPHY (WATER RESOURCES ENGINEERING)

DEPARTMENT OF WATER RESOURCES ENGINEERING BANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY DHAKA, BANGLADESH

FEBRUARY, 2018

STUDY ON SURFACE WATER AVAILABILITY FOR FUTURE WATER DEMAND FOR DHAKA CITY

by Md Ehsanul Haque

A thesis submitted to the Department of Water Resources Engineering Bangladesh University of Engineering and Technology, Dhaka in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY (WATER RESOURCES ENGINEERING)

DEPARTMENT OF WATER RESOURCES ENGINEERING BANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY DHAKA, BANGLADESH

February, 2018

CERTIFICATE OF APPROVAL

Signature of the Student

Md Ehsanul Haque

Signature of the Supervisor

Professor Dr. Md. Abdul Matin

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To My Father Late Lt Col Shamsul Haque & My Mother Mrs Suraiya Haque

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ACKNOWLEDGEMENTS

All praises are solely to the most merciful and beneficent Almighty Allah for enabling the author to complete the research work and to prepare this manuscript for fulfillment of the degree of Doctor of Philosophy in Water Resources Engineering. The author deems it is a great pleasure and honor to express his deep sense of gratitude, heartfelt indebtedness and sincere appreciation to his Thesis Supervisor Professor Dr. Md. Abdul. Matin, Department of Water Resources Engineering, Bangladesh University of Engineering and Technology for providing scholastic guidance, supervision and affectionate inspiration for successful achievement and outstanding contribution of the research work as well as preparation of this thesis. The author extends his sincere appreciation and immense indebtedness to his research to the distinguished members Professor Dr. M. R. Kabir, Professor Dr. Muhammad Ashraf Ali, Professor Dr. Md. Sabbir Mostafa Khan, Professor Dr. Md. Ataur Rahman, Professor Dr. Afzal Ahmed and Professor Dr. Md. Mostafa Ali for their profound interest, valued suggestions, and praiseworthy co-operation for the accomplishment of the research work. The author would like to express his deep sense of respect to all other teachers and staffs of the Department of Water Resources Engineering for their valuable teaching, suggestions and encouragement for improving his academic knowledge during the period of his study degree of Doctor of Philosophy. The author feels it necessary to express his indebtedness to S. M. Mahbubur Rahman and Dr. Asif Zaman for their great assistance during analyses work. The author expresses the deepest respect and love for his familiar members who have been supporting him for his successful life. Finally, the author also expresses profound indebtedness to his beloved mother, inspiring wife and sweet daughter for their honest and heartfelt co-operation during every moment of the research work.

The Author

ABSTRACT

Dhaka, the capital of Bangladesh, is one of the fastest growing cities of the world. It remains a great challenge to ensure uninterrupted water supply in the city with adequate quantity and quality round the year. Necessary measures are undertaken to meet the growing demand of water supply which is presently dependent on abstraction of groundwater. It appears that no further abstraction is feasible as the groundwater level is declining very fast. To reduce the overwhelming dependence on groundwater resources, surface water in the vicinity of the Dhaka city can be utilized.

This study deals with the surface water availability to meet the growing demand of Dhaka city water supply. Primarily, the existing water supply system of the city has been reviewed to ascertain the possible reasons of water supply crisis. Review illustrated that rapid groundwater depletion caused by excessive extraction, extreme surface water pollution through industrial waste and sewage disposal are the major reasons of water crisis of the city.

Realizing the necessity to explore options of water supply system, potentials of all available sources were critically examined through a detail analysis involving tools such as survey, investigation, test of water quality parameter, preparation of flow and water level hydrographs, determination of environmental flow and hydrodynamic HEC-RAS model analysis. The study includes water demand and population projection upto 2035.

The city is surrounded by six rivers i.e., Balu, Buriganga, Sitalakhya, Dhaleswari, Turag and Tongi khal and more so connected with two nearby large rivers such as Padma and Meghna. The quality of water of all these surface water sources has been studied. Analyses showed that the Balu, Buriganga, Turag and Tongi khal contain more pollutant in dry season. However, for Dhaleswari, Sitalakhya, Padma and Meghna contain lesser pollution. The situation worsens in dry season due to lack of precipitation and reduced upstream flow resulting in low DO and high concentration BOD, COD, ammonium and phosphate. The assessment revealed that the water of Dhaleswari, Sitalakhya, Padma and Meghna remain usable after treatment throughout the year. The water quality from the rivers Balu, Buriganga, Turag and Tongi khal found to be improved for the wet period from May to November. To determine the water availability, flow and water level hydrographs of 10 years from 2006 to 2016 have been used for the analyses. The flow

v exceedance curve was prepared for the analysis of determination of environmental flow.

The environmental flow was calculated by Tenant, Q50 and Q90 methods. The aspects of navigability of the rivers have also been considered to assess the impact of water withdrawal from the selected sources. Thus, the absrtactable water was determined from the available flow. Hydrodynamic of the river network using HEC-RAS was simulated for various abstraction scenarios. It was observed that water velocity, depth and water level of the selected rivers also decreased from the base flow condition after withdrawal of required water. In terms of availability, it was observed that Buriganga, Balu, Sitalakhya, Dhaleswari, Padma and Meghna are good source of surface water. These sources can provide total amount of estimated future demand subjected to proper treatment upto year 2035. An evaluation has also been made for the surface water sources considering their available quantity, required quality and cost effectiveness. In terms of cost effectiveness, it was found that peripheral rivers are more economical compared to large rivers due to nearby location from the city. Thus, from both data analysis and model simulation, it is evident that surface water from rivers can solve the water crisis of the Dhaka City. The operation plan for future water demand as proposed in this study will be able to provide water requirements till the year 2035. It can be opined that results and suggestions put forward in this study can be considered as an initial step towards successful attainment of sustainable development goals for water management and sanitation.

TABLE OF CONTENTS

Declaration………………………………………………………………………………… i

Acknowledgement ………………………………………………………………………… iii

Abstract …………………………………………………………………………………… iv

Table of Contents …………………………………………………………………………. vi

List of Figures …………………………………………………………………………….. xi

List of Tables ……………………………………………………………………………… xvi

List of Abbrebiations ……………………………………………………………………… xix

CHAPTER 1 INTRODUCTION ……………………………………………….………... 1 1.1 General …………………………………………………………………….. 1 1.2 Rationale of this Study ...... 4 1.3 Study Area ...... ……………………………………...... ……. 6 1.4 Brief Description of the Peripheral Rivers System ………………………. 8 1.5 Scope and Objectives of the study ……………………………………….. 10 1.6 Organization of the Report.……………………………………………… 11

CHAPTER 2 LITERATURE REVIEW ……………………………………………….... 12 2.1 Introduction ………………………………………………………………… 12 2.2 Description of Water Quality Parameters ...... 12 2.3 Quantification of Water Availability …………………………………….... 17 2.3.1 Flow Duration Curve ...... 17 2.3.2 Environmental Flow ...... 17 2.3.3 Use of Mathematical Model (HEC-RAS)...... 18 2.4 Review of Water Supply Assessment in Various Countries ...... 19 2.4.1 Water Demand Management in Srilanka ...... 21 2.4.2 Water Supply Management in India ...... 22 2.4.3 Water Supply Management in Nepal...... 23 2.4.4 Surface Water Management Plan (SWMP) in London...... 24 2.4.5 Surface Water Management Plan in New York, USA...... 26 2.5 Water Supply Scenario in Different Cities ...... 27

2.6 System Loss in Different Cities...... 28 2.7 Review of Studies on Surface Water Quality of rivers around Dhaka City..... 28 2.8 Review of Previous Studies on Groundwater Quality ...... 32 2.9 Deep Tube Wells Operated by Private Agencies ...... 34 2.10 Relevant Studies of Dhaka Water and Sewage Authority (DWASA)...... 34 2.11 Management Plan for Water Supply Project ...... 37 2.11.1 Demand and Supply Side Management ...... 37 2.11.2 Water Reuse ……………………………………………………………………. 37 2.11.3 Pollution control …………………………………………………………….. 36 2.11.4 Integration of Future Sources of Supply……………………………………….. 38 2.11.5 Water Distribution System ………………………………………..……..…….. 38 2.11.6 Environmental Impact Assessment (EIA) of Industries…………..……..…….. 39 2.11.7 Enforcement of New Law: “Clean Water Act”………..……. .…… .…… .……. 39 2.11.8 Land Zoning……..……. .…… . …… .…… …… .…… …… .…… …… .……. 40 2.11.9 Coordinated Efforts ……..……. .…… . …… .…… …… .…… …… .…… …. 41 2.11.10 Maintaining ISO 14000 in industries…. .…… . …… .…… …… .…… ……. 41 2.11.11 Waste minimization in industrial processes….… . …… .…… …… .…… … 41 2.11.12 Environmental Monitoring Program ….… . …… .…… …… …… .…… …. 42 2.11.13 Clean-Up of Contaminated River Beds ….… . …… .…… …… …… .…… 42 2.11.14 Rainwater Harvesting ...... ….. 43 2.11.15 Institutional Responsibilities … . …… .…… …… …… . ……………….. 43 2.12 Concluding Remarks………………………………………………………. ….. 44

CHAPTER 3 METHODOLOGY ………………………….……………………… 45

3.1 Introduction ………………………………………………………………… 45 3.2 Methodology ………………………………………………………………… 46 3.2.1 Population Prediction and Assessment of Water Demand…………………… 46 3.2.2 Water Quality Analysis ……………………………………………………… 47 3.2.3 Ground Water Data …………………………………………………………… 50 3.2.4 River Data …………………………………………………………………… 50 3.2.4.1 Bathymetry …………………………………………………………………… 50 3.2.4.2 Water Level and Discharge …………………………………………………… 50

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3.2.5 Analysis of Water Availability ……………………………………………….. 51 3.2.5.1Application of Mathematical Model…………………………………………… 51 3.2.5.2 Model Calibration and Validation …………………………………………… 52 3.2.5. Analysis for Surface Water Withdrawal ……………………………………… 52 3.2.6. Evaluation of Sources ………………………………………………………… 53 3.3 Flow Diagram Showing Overall Methodology of the Study ………………… 53 3.4 Concluding Remarks ………………………………………………………… 56

CHAPTER 4 ASSESSMENT OF FUTURE WATER DEMAND 57

4.1 Introduction………………………………………………………………...... 57 4.2 Present Situation of Groundwater DTWs ………………………………...... 57 4.3 Surface Water Treatment Plants (SWTP) Operated by DWASA.....……...... 60 4.4 Water Supply as Surface Water from River Sources...... ……...... 61 4.5 Population Projection...... … …...... …...... …...... …...... …...... …...... 61 4.6 Future Water Demand Assessment…...... …...... …...... …...... …...... …...... 62 4.6.1 Residential Water Demand …...... …...... …...... …...... …...... …...... …...... 63 4.6.2 Non Residential Water Demand …...... …...... …...... …...... …...... …...... …...... 63 4.6.3 Total Future Water Demand …...... …...... …...... …...... …...... …...... …...... 63 4.7 Concluding Remarks …...... ….....…...... …...... …...... …...... …...... …...... 66

CHAPTER 5 ASSESSMENT OF WATER QUALITY ………………………………… 67 5.1 General …………………..……………………………..………………….. 67 5.2 Water Quality Parameters ………………………………………………… 67 5.3 Water Quality Padma and Meghna Rivers ……………………………….. 68 5.4 Water Quality of Balu River ...... 79 5.5 Water Quality of Sitalakhya River ...... 84 5.6 Water Quality of Turag River ...... 89 5.7 Water Quality of Buriganga River ...... 90 5.8 Water Quality of Dhaleshwari River ...... 95 5.9 Yearly Variation of Water Quality Parameters of the River System ………. 96 5.10 Summary of Pollutant Loading of Surface Water System of Dhaka City .... 102

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5.11 Collection and Analysis of Water Samples...... ……….……. 105 5.12 Summary and Concluding Remarks……………………………….……. 107

CHAPTER 6 ANALYSIS OF SURFACE WATER AVAILABILITY……………...... 111 6.1 Introduction ………………………………………………………………... 111 6.2 Description of Selected River Sources for Surface Water .…………...... 111 6.3 Peripheral Rivers and Major Rivers for Water Availability ……………… 113 6.4 Monthly Average Flow and Water Level Hydrograph ………………….. . 113 6.5 Environmental Flow Estimation ……………………………...... ……… 122 6.5.1 Assessment of 10% Mean Annual Flow ...... 122 6.5.2 Estimation from Flow Duration curve in terms of Q90 and Q50 ...... 123 6.6 Suitability of River Data ……………………………………………. 128 6.7 Navigability ………………………………………………………….……. 127 6.8 Water Availability of Surface Water Sources ……………………………. 131 6.9 Effect of Water Withdrawal using HEC RAS 1D Model …………….… 134 6.9.1 Hydrodynamic Model Results and Analysis …………………………….. 134 6.9.2 Model Setup ……………………………………………………..………. 138 6.9.3 Calibration and Validation of the Hydrodynamic Model:……………….... 139 6.9.4 Model Results for Various Abstraction Scenarios………………………… 145 6.9.5 Analysis of Turag River ………………………………………..………… 149 6.9.6 Analysis of Tongi Khal ……………………………..…………………….. 150 6.9.7 Analysis of Balu River ……………………………….………………….. 152 6.9.8 Analysis of Buriganga River ...... 153 6.9.9 Analysis of Sitalakhya River...... 155 6.9.10 Analysis of Dhaleswari River ...... 157 6.10 Summary Results of the Base and Withdrawal Scenario ...... 158 6.11 Summary and Discussions ...... 162

CHAPTER 7 EVALUATION OF SURFACE WATER SOURCES FOR DHAKA CITY 165 7.1 General………………………………………………………………….. 165 7.2 Suggested Surface Water Withdrawal for Treatment ……………………….. 166 7.3 Evaluation Criteria ...... ……………………………………………… 171 7.3.1 Water Quality of Peripheral Rivers…………………………………………… 171 ix

7.3.2 Water Quality of Large Rivers………………………………………………… 172 7.4 Cost Estimation ……………………………………………………………… 173 7.4.1 Capital Expenditure …………………………………………………………… 173 7.4.2 Operation Expenditure………………………………………………………… 174 7.4.3 Cost of Water per MLD………………………………………………………. 174 7.5 Cost Effectiveness ………………………………………………………….... 175 7.6 Overall Index of the Surface Water Sources………………………………… 175 7.7 Evaluation of Water Availability versus Water Quality……………...... 176 7.8 Evaluation of Water Availability versus Cost Effectiveness……………….. 176 7.9 Suggested SWTP to be Operational…………………….……….…….……… 177 7.9.1 Utilization of Large Rivers ……………….………………….……………… 178 7.9.2 Paradigm Shifting towards Surface Water Sources ...... 179 7.10 Financial Plan ...... 180 7.11 Concluding Remarks.…….…….… ….….…….….…….….…….….…..…. 180

CHAPTER 8 CONCLUSIONS AND RECOMMENDATIONS ……………………… . 182 8.1 General…………………………………..……………………………...... 182 8.2 Conclusions……………………………..……………………………...... 182 8.3 Recommendations for Future Study …………………………………….... 185

REFERENCES……………………………………………………………………………… 186

LIST OF FIGURES

Figure 1.1 Water Supply Sources of Dhaka City ……………………..………………... 3 Figure 1.2 Peripheral Rivers around Dhaka City ………………………..………………... 4 Firure 1.3 Field Survey for Demand and Supply ………………………………… 5 Figure 1.4 Map of Study Area …………….…………………………………….……… 7 Figure 2.1 Diagram showing the coherence in plans and policy……………………….. 26 Figure 2.2 Water Supply Scenario in different cities ………….……………………….. 27 Figure 2.3 System loss in cities of neighboring countries ………….……………………….. 28 Figure 3.1 Large and Peripheral River Network...... 45 Figure 3.2 Locations of Water Quality Stations...... 40 Figure 3.3 Water Samples from Rivers in September 2017...... 49 Figure 3.4 Water Samples from Rivers in January 2018...... 49 Figure 3.5 Model Domain and Hydrometric Stations...... 44 Figure 3.6 Flow Diagram of Evaluating the Sources...... 53 Figure 3.7 Flow diagram showing the Methodology of this study ...... 55 Figure 4.1 Increasing trend of DTWs over the years …………………..……… 57 Figure 4.2 Gradual increase in mining depth of DTWS …..……………………………. 58 Figure 4.3 Groundwater depletion state in Lalbagh, Motijheel and Cantonment ……. 59 Figure 4.4 Groundwater depletion state in Tejgaon, Gulshan and Dhanmondi………… 59 Figure 4.5 Seasonal variations in monthly production of SWTPs………………… …… 61 Figure 4.6 Population trend of Dhaka from 1975 to 2010 .…..…………………...... 62 Figure 4.7 Map showing population density of Dhaka city.…….…… …………………. 64 Figure 5.1 Sampling Locations of Padma River on Google Earth ...... …….. 69 Figure 5.2 Sampling Locations of Meghna River on Google Earth ...... 70 Figure 5.3 pH along Padma River for the year 2015 (Data source: WARPO) ...... 70 Figure 5.4 pH along Meghna River for the year 2016 ...... 71 Figure 5.5 EC along Padma and Meghna Rivers at Jashaldia and Bishnandi...... 72 Figure 5.6 Monthly EC along Major Rivers at sampling points...... 72 Figure 5.7 Chloride concentration along Major Rivers at Jashaldia and Bishnandi...... 73 Figure 5.8 Chloride concentration along Major Rivers in 2016...... 73 Figure 5.9 Average Yearly Turbidity along Major Rivers ...... 74 Figure 5.10 Yearly BOD along Padma and Meghna Rivers...... 74 Figure 5.11 Sampling stations along Balu River...... 79 xi

Figure 5.12 pH along the Balu River...... 81 Figure 5.13 Spatial Variation of Dissolved Oxygen along the Balu River reach of 42 km…... 82 Figure 5.14 BOD along the Balu River ……………………………………………………….. . 83 Figure 5.15 TDS along the Balu River ………………………………………………………. 83 Figure 5.16 Chloride (top) along the Balu River………………………………………………. 84 Figure 5.17 Water Quality Sampling Stations for Sitalakhya River …………………………. 85 Figure 5.18 pH of Sitalakhya River for the year 2016……………………………… …..……. 85 Figure 5.19 BOD of Sitalakhya River 2016……………………………… …..……. …..…… 86 Figure 5.20 DO concentration of Sitalakhya River for 2016..…………… …..……. …..…… 87 Figure 5.21 Turbidity of Sitalakhya River for the year 2016..…………… …..……. …..…… 87 Figure 5.22 Total Alkalinity of Sitalakhya River for 2016..…………… …..………. …..…… 88 Figure 5.23 TDS (left) and Chloride (right) of Sitalakhya River for 2016…..………. …..…… 88 Figure 5.24 pH(left) and BOD(right) along Turag River in 2016…..……..……..……. …..… 89 Figure 5.25 Chloride (Left) and Turbidity (right) along Turag River in 2016…...……. …..……89 Figure 5.26 TDS along Turag River in 2016…...…...…...…...…...…...…...…...……. …..……. 90 Figure 5.27 Locations of Buriganga River …...…...…...…...…...…...…...…...………. …..…… 91 Figure 5.28 pH along Buriganga River for 2016...…...... …...... …...…...…...………. …..…… 92 Figure 5.29 Chloride along Buriganga River in 2016...…...... …...... …...…..………. …..…….. 92 Figure 5.30 Turbidity along Buriganga River for 2016...…...... …...... …...…..………. …….….93 Figure 5.31 TDS along Buriganga River for 2016...…...... …...... …...….. ……………. …….…93 Figure 5.32 DO along Buriganga River for 2016...…...... …...... …...….. ……………. …….….94 Figure 5.33 BOD along Buriganga River for 2016...…...... …...... …...….. ……………. ………95 Figure 5.34 Water quality parameters along Buriganga River for 2016.….. …………… …….. 96 Figure 5.35 Trend of BOD in peripheral rivers of Dhaka City.….. …………… ………… … 97 Figure 5.35 Trend of DO in peripheral rivers of Dhaka City.… .. …………… ………… … 97 Figure 5.37 Trend of Turbidity in peripheral rivers of Dhaka City ...... 98 Figure 5.38 Trend of pH in peripheral rivers of Dhaka City ...... 98 Figure 5.39 Trend of Chloride in peripheral rivers of Dhaka City ...... 99 Figure 5.40 Trend of Cadmium in peripheral rivers of Dhaka City ...... 100 Figure 5.41 Trend of Chromium in peripheral rivers of Dhaka City ...... 100 Figure 5.42 Trend of Pb in peripheral rivers of Dhaka City ...... 101 Figure 5.43 Trend of Zn in peripheral rivers of Dhaka City ...... 101 Figure 5.44 Trend of Nickel in peripheral rivers of Dhaka City ...... 102

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Figure 6.1 Location of Rivers around Dhaka and their Hydraulic connection ...... 112 Figure 6.2 Flow Hydrograph of Turag River...... 113 Figure 6.3 Flow Hydrograph of Tongi khal...... 114 Figure 6.4 Flow Hydrograph of Balu ...... 114 Figure 6.5 Flow Hydrograph of Buriganga ...... 115 Figure 6.6 Flow Hydrograph of Sitalakhaya ...... 115 Figure 6.7 Flow Hydrograph of Dhalaeswari ...... 116 Figure 6.8 Flow Hydrograph of Padma ...... 116 Figure 6.9 Flow Hydrograph of Meghna ...... 117 Figure 6.10 Water Level Hydrograph of Turag ...... 117 Figure 6.11 Water Level Hydrograph of Tongi Khal ...... 118 Figure 6.12 Water Level Hydrograph of Balu ...... 118 Figure 6.13 Water Level Hydrograph of Buriganga ...... 119 Figure 6.14 Water Level Hydrograph of Sitalakhya ...... 119 Figure 6.15 Water Level Hydrograph of Dhaleswari ...... 120 Figure 6.16 Water Level Hydrograph of Padma ...... 120 Figure 6.17 Water Level Hydrograph of Meghna ...... 121 Figure 6.18 Flow Duration Curve of Turag River ...... 123 Figure 6.19 Flow Duration Curve of Tongi River ...... 124 Figure 6.20 Flow Duration Curve of Balu River ...... 124 Figure 6.21 Flow Duration Curve of Buriganga River ...... 125 Figure 6.22 Flow Duration Curve of Sitalakhya River ...... 125 Figure 6.23 Flow Duration Curve of Daleshwari River ...... 126 Figure 6.24 Flow Duration Curve of Padma River ...... 126 Figure 6.25: Flow Duration Curve of Meghna River ...... 127 Figure 6.26: Available Depths of Peripheral Rivers...... 130 Figure 6.27: HEC RAS Model Boundary Locations ...... 135 Figure 6.28 Boundary discharge (Q) data of Balu river...... 136 Figure 6.29 Boundary Discharge (Q) data of Lakhya River...... 136 Figure 6.30 Boundary Discharge (Q) data of Turag River...... 137 Figure 6.31 Boundary Discharge (Q) data of Dhaleswari River...... 137 Figure 6.32 Boundary Water level (WL) data of Dhaleswari River...... 138 Figure 6.33: Hydrodynamic model Set up of River network...... 139

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Figure 6.34: Calibration of the numerical model of Turag River in Year 2014 ...... 140 Figure 6.35: Validation of the numerical model of Turag River in Year 2015 ...... 140 Figure 6.36: Calibration of the numerical model of Tongi Khal in Year 2014 ...... 141 Figure 6.37: Validation of the numerical model of Tongi Khal in Year 2015 ...... 141 Figure 6.38: Calibration of the numerical model of Balu River in Year 2014 ...... 142 Figure 6.39: Validation of the numerical model of Balu River in Year 2015 ...... 142 Figure 6.40: Calibration of the numerical model of Buriganga River in Year 2014 ...... 143 Figure 6.41: Validation of the numerical model of Buriganga River in Year 2015 ...... 143 Figure 6.42: Calibration of the numerical model of Sitalakhya River in Year 2014 ...... 144 Figure 6.43: Validation of the numerical model of Sitalakhya River in Year 2015 ...... 144 Figure 6.44: Calibration of the numerical model of Dhaleswari River in Year 2014 ...... 145 Figure 6.45: Validation of the numerical model of Dhaleswari River in Year 2015 ...... 145 Figure 6.46: Map showing the abstraction points in the river network...... 147 Figure 6.47: Variation of Velocity Before and After Abstraction along the Turag River ...... 149 Figure 6.48: Variation of Water Level Before and After Abstraction along the Turag River ... 149 Figure 6.49: Variation of Water Depth Before and After Abstraction along the Turag River... 150 Figure 6.50: Variation of Velocity Before and After Abstraction along the Tongi River ...... 150 Figure 6.51: Variation of Water Level Before and After Abstraction along the Tongi Khal .... 151 Figure 6.52: Variation of Water Depth Before and After Abstraction along the Tongi Khal .... 151 Figure 6.53: Variation of Velocity Before and After Abstraction along the Balu River ...... 152 Figure 6.54: Variation of Water Level Before and After Abstraction along the Balu River ..... 153 Figure 6.55: Variation of Water Depth Before and After Abstraction along the Balu River .... 153 Figure 6.56: Variation of Velocity Before and After Abstraction along the Buriganga River .. 154 Figure 6.57: Variation of Water Level Before and After Abstraction along the Buriganga River. 154 Figure 6.58: Variation of Water Depth Before and After Abstraction along the Buriganga River.. 155 Figure 6.59: Variation of Velocity Before and After Abstraction along the Shitalakya River ...... 155 Figure 6.60: Variation of Water Level Before and After Abstraction along the Sitalakhya River . 156 Figure 6.61: Variation of Water Depth Before and After Abstraction along the Sitalakhya River . 156 Figure 6.62: Variation of Velocity Before and After Abstraction along the Dhaleswari River .... 157 Figure 6.63 Variation of Water Level Before and After Abstraction along the Dhalewari River .. 157 Figure 6.64 Variation of Water Depth Before and After Abstraction along the Dhaleswari River .158 Figure 7.1 Prediction of demand components of Dhaka city...... 160 Figure 7.2 Net Water Availability of Balu River ……………….………….………….… 167

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Figure 7.3 Net Water Availability of Turag River …………….………….………….… 167 Figure 7.4 Net Water Availability of Tongi River………………….………….………….… 168 Figure 7.5 Net Water Availability of Buriganga River ………….………….………….… 168 Figure 7.6 Net Water Availability of Sitallakhya River ………….………….………….… 169 Figure 7.7 Net Water Availability of Dhaleswari River ……….………….………….… 169 Figure 7.8 Net Water Availability of Padma River ……….………….………………… 170 Figure 7.9 Net Water Availability of Meghna River ………….………….……………… 170 Figure 7.10 Important Water Quality Parameters of Peripheral Rivers …………………. 172 Figure 7.11 Comparisons of Water Quality Parameters between Two Large Rivers (Padma and Meghna) and One of the Peripheral Rivers (Buriganaga) ……………………………… 172 Figure 7.12 Water availability and Quality.. …………………………………………… .. 176 Figure 7.13 Water Availability and Cost Effectiveness…………………………………. 177 Figure 7.14 Shift towards surface water from ground water …………………...……….. 180

LIST OF TABLES

Table 1.1 Study Area Coverage ………………………………………………………. 8 Table 1.2 Summary of Peripheral Rivers ……………………………………….. 10 Table 2.1 Important Water Quality Standards ……………………………………….. 16 Table 2.2 Water Supply Scenario in different cities …………………………..……… 27 Table 2.3 Population, water supply and demand for various ……..……..……..……… 30 Table 2.4 Priority of Evaluating of Additional Measures…………………………….…. 42 Table 3.1 Water quality monitoring station of DOE ………………………………… 47 Table 3.2 Water quality monitoring station of DWASA (2014 -2016)……………… 48 Table 3.3 Bathymetry Data ………………………………………………………… 50 Table 3.4 Water Level and Discharge Stations …………………………………… 51 Table 3.5 Summary of the activities …………………………………………… 56 Table 4.1 Groundwater Depletion State in Lalbag, Motijheel, Cantonment, Mirpur, Tejgoan and Dhanmondi...... 58 Table 4.2 Details of SWTPs...... 60 Table 4.3 Population Projection …………………...…………...... 62 Table 4.4 Breakdown of indoor household water consumption from field survey...... 63 Table 4.5 Estimation of projected water demand from 2017 upto 2035...... 65 Table 4.6 Estimation of projected water demand from 2040 upto 2060...... 65 Table 5.1 Locations for the analysis of water quality parameters of Padma River) …. 69 Table 5.2(a) Summary characteristics of surface water samples collected in July 2009... . 75 Table 5.2(b) Summary characteristics of surface water samples collected in November 2009 75 Table 5.3 Water Quality Test Results from Meghna River at Meghna Ghat, Narayanganj 77 Table 5.4 Four water quality parameters of Balu River ...... 80 Table 5.5 DO Sample of Balu River for a stretch of 42 km ...... 81 Table 5.6 Locations for the analysis of water quality parameters of Buriganga River ... 91

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Table 5.7 Summary of pH Parameter ...... 102 Table 5.8 Summary of Turbidity Parameter ...... 102 Table 5.9 Summary of Chloride Parameter ...... 103 Table 5.10 Summary of NH4 Parameter ...... 103 Table 5.11 Summary of DO Parameter ...... 103 Table 5.12 Summary of BOD Parameter ...... 104 Table 5.13 Summary of TDS Parameter ...... 104 Table 5.14 Summary of Lead (Pb) Parameter ...... 104 Table 5.15 Summary of Cadmium (Cd) Pollution Parameter ...... 105 Table 5.16 Summary of Chromium (Cr) Pollution Parameter ...... 105 Table 5.17 Summary of Zinc (Zn) Pollution Parameter ...... 105 Table 5.18 Summary of Mercury (Hg) Pollution Parameter ...... 106 Table 5.19 Summary of Phosphate (PO4) Pollution Parameter ...... 106 Table 5.20 Summary of Pollutant Loading in the Peripheral Rivers ...... 107 Table 5.21 Important Flow Characteristics of Padma River ………………………….... 107 Table 5.22 Important Value of Padma River ………………...... 108 Table 6.1 Distance from Dhaka to All Surrounding Rivers ...... ……. 112 Table 6.2 Monthly Mean flow for all the peripheral rivers in m3/s ...... 121 Table 6.3 Environmental Flow Requirement using 10% MAF Method ...... 123

Table 6.4 Flow Q90 and Q50 for the selected rivers...... 127 Table 6.5 Water Quality of Peripheral and Major Rivers (Conferred from Chapter 5) . 128 Table 6.6 Classification of IWT Route according to BIWTA ...... 128

Table 6.7 Available Depths, Water level and Navigability of Peripheral Rivers...... 129

Table 6.8 Availability of Surface Water ...... 131 Table 6.9 Scenarios of HD Model Run...... 148 Table 6.10 Model Results for Base and Withdrawal Scenario of January...... 158 Table 6.11 Model Results for Base and Withdrawal Scenario of February...... 159 Table 6.12 Model Results for Base and Withdrawal Scenario of March...... 159 Table6.13 Model Results for Base and Withdrawal Scenario of April ...... 159 Table 6.14 Model Results for Base and Withdrawal Scenario of May ...... 160 Table6.15 Model Results for Base and Withdrawal Scenario of June...... 160 Table 6.16 Model Results for Base and Withdrawal Scenario of Jul ...... 160 Table 6.17 Model Results for Base and Withdrawal Scenario of Aug ...... 161 xvii

Table 6.18 Model Results for Base and Withdrawal Scenario of Sep...... 161 Table 6.19 Model Results for Base and Withdrawal Scenario of Oct...... 161 Table 6.20 Model Results for Base and Withdrawal Scenario of Nov ...... 162 Table 6.21 Model Results for Base and Withdrawal Scenario of Dec ...... 162 Table 7.1 Water Availability Index ……………………………………………………… 171 Table 7.2 Dry Period Water Quality Index ...... 173 Table 7.3 Total Water Treatment Plant (WTP) Cost ....………………………………... 173 Table 7.4 Operational Expenditure ……………………………………………………… 174 Table 7.5 Cost per MLD ...... 175 Table 7.6 Cost Effectiveness ……………………………………………………………. 175 Table 7.7 Overall Index of all the Rivers ……………………………………………….. 176 Table 7.8 Estimated Water Availability from Peripheral Rivers ………………………… 178 Table 7.9 Ongoing Water Utilization Plan of Large Rivers …………………………… 178 Table 7.10 Suggested Plan for Future Water Production ...... 179 Table 7.11 Year-wise Financial Requirement (Crore Taka) ……………………………. 180

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LIST OF ABBREVIATIONS

Abbreviation Meaning BBS Bangladesh Bureau of Statistics

BGMEA Bangladesh Garment Manufacturers and Exporters Association

BOD Biochemical Oxygen Demand

BUET Bangladesh University of Engineering and Technology

BWDB Bangladesh Water Development Board cumec Cubic Meter per Second

DOE Department of Environment

DOH Department of Hydrology

DTW Deep Tube Well

DWASA Dhaka Water Supply and Sewerage Authority

EPB Export Promotion Bureau

FGD Focus Group Discussion

GIS Global Information System gpcd Gallon per Capita per Day

IDI In-depth Interview

IWM Institute of Water Modeling

KII Key Informant Interview km Kilometer

LIC Low Income Community lpcd Liter per Capita per Day

MIST Military Institute of Science and Technology

MLD Million Liter per Day

NSU North South University

xix

NTU Nephelometric Turbidity Units

Pt-Co Platinum-Cobalt

SPSS Statistical Package for the Social Sciences

SWTP Surface Water Treatment Plant

WARPO Water Resource Planning Organization

WHO World Health Organization

CHAPTER ONE

INTRODUCTION

1.1 General

Water constitutes two-thirds of the surface of the earth. Water is an indispensable constituent of all organisms and usually a good solvent for a large variety of ingredients. Moreover, being necessary for most biotic processes makes it one of the major modules of socio-economic development and scarcity alleviation. Water resources have infinite importance in human survival, socio-economic stability and environmental sustainability. Though water covers 71 percent of the earth's surface, but only three percent is fresh water out of which 69 percent is "trapped" as ice, mainly in the two Polar Regions. The remaining freshwater occurs in rivers, lakes and aquifers which human being, plants and other animal species can use. The distribution must be carefully managed to avoid irreversible depletion of the resource (WHO/UNICEF JMP, 2012 ). United Nations proclaimed that the water act as a dynamic force for a continued development and a strategic tool to fight against poverty as per concept of sustainable development goals. 2.6 billion people have gained access to improved drinking water sources since 1990, but 663 million people are still without safe water. Ensure access to water and sanitation for all is the main concept of United Nations Sustainable Development Goals (http/www.un.org). Moreover, this study also focuses implementation towards Sustainable Development Goal (SDG- 6) prescribed by United Nations in 2016.

Water scarcity has been triggering conflict since a long time due to many tangible and intanib factors. Kjellén and McGranahan (1997) predicted that two-thirds of the world’s population will experience water stress condition by 2025. Many countries will experience high water stress condition where available water resources withdrawal exceeds the limit. Statistics showed that one in eight people does not have access to safe drinking water and two of five people do not have adequate sanitation worldwide (Water Aid, 2010). Life cannot sustain without water. Moreover, lack of access to adequate safe water leads to the spreading of diseases. Children and women bear the greatest health burden associated with unsafe water and sanitation. World Health Organization (2012) estimated that 1.73 million deaths occur each year due to diarrheal diseases attributed from poor water supply, sanitation and hygiene. This situation becomes more problematic in South Asia, where withdrawal rate against available resources is 48 percent (Ariyabandu, 1999).

Bangladesh being a riverine country has been facing many fold challenges from safe drinking water, say for example, unlimited flood water during wet season, increasing scarcity during dry season and management of all resources under serious threat. Water experiences socio-ecological resource management at which decisions are made for water scheming does not match with its requirement. The urban water management requires a systematic process that includes planning, research, design, engineering, regulation, and administration. Under this circumstance, the current study has attempted to comprehend the present and future trend and extent of water demand and supply. This study will be carried out through analyzing status of surface and groundwater and options for surface water availability sources based upon future demand and supply projection. Particular attention has been given to elucidate the quantity, quality and cost effectiveness to achieve safe water to meet the future demand of Dhaka city.

A rapid increase in the pace of rural-urban migration has been very explicit in the recent decades in Bangladesh. The urbanization coupled with pressure from fast-rising population has been exposing the city authorities to a growing demand for increased quality and quantum of urban-specific services. Now challenges due to rapid urbanization are multidimensional. Dhaka city has been increasing in its volume with an annual rate of 3.5 percent following an unsystematic approach (Islam et al., 2009) to accommodate huge population influx of more than seven million (BBS, 2009) people. Such urban sprawl exerts immense pressure on the infrastructures of the city. The city inhabitants, therefore, are deprived of basic amenities of urban life where water supply has appeared as the most critical issue. At present, water demand has surpassed the water supply where 25 percent of the total population of Dhaka city has no direct access to potable water (Nishat, et al., 2008). Dhaka Water Supply and Sewerage Authority (DWASA) is the stakeholder and responsible for water supply throughout the city, which has revised their area of responsibility over the years. Dhaka Statistical Metropolitan Area (DSMA) covers an area of 1353 km2, out of which Dhaka Metropolitan Area (DMA) constitutes 27 percent (360 km2). Until 1989, Dhaka Water Supply and Sewerage Authority (DWASA) operation was limited to DMA. In 1990 DWASA extended operating area to adjacent Narayangonj metropolitan area. In recent times, Dhaka city is facing more difficulties in maintaining adequate water supply mainly due to following reasons:

a. Rapidly growing population and demand b. Declining of ground water level c. Inadequate surface water to cope with the future demand d. Poor raw water quality

e. Leakages in the system network f. Existing inadequate pipe network design

In addition, the city water supply system is also facing challenges due to unplanned city development and informal settlements, switching to surface water instead of groundwater and requirement of large financial investment. However, Dhaka city water supply system has also number of achievements. The main achievements are increase of water production, improved service quality, reduction of non-revenue water and provision of water supply at low cost.

Dhaka city water supply is mostly dependent on groundwater. As of June 2016, 78% is from groundwater sources tapping through Deep Tube wells (DTW); the remaining 22% of the water is supplied from the water treatment plants situated at Saidabad, Chadnighat and two smaller units at Narayanganj (Figure 1.1).

Sources of water

22%

Surface water Ground water

78%

Figure 1.1: Water Supply Sources of Dhaka City (DWASA, 2014)

With a population of over 15 million Dhaka is one of the most congested cities of the world. This rapidly growing city is located on the northern bank of the river Buriganga and surrounded by other rivers, namely, the Turag to the west, the Tongi Khal to the north and the Balu to the east. The rivers surrounding Dhaka are an advantage to it and essential for the survival of the mega city as these provide drainage system, drinking water, different kinds of fishes and also waterways for traveling (BBS, 2010). In order to meet the growing demand, DWASA is installing high capacity water wells tapping the upper dupitila aquifers. This upper aquifer is in stressed condition. In most part of the city area, the groundwater recharge in upper aquifer is much less compared to the abstraction, causing groundwater depletion. The average groundwater depletion in most of the areas in the city is around 2-3 m/year (DWASA, 2015). The present rate of depletion is alarming and may cause devastating events like land subsidence and other environmental degradation. This gives an

alarming indication that there is an urgent need to alleviate pressure on the upper aquifer being exploited and explore for more suitable and sustainable sources to supplement the present water supply. To some extent, Dhaka city has number of peripheral rivers (Figure 1.2) as the nearest source of surface water and those can be utilized for future water supply. This idea of using surface water as future source is taken seriously by the concerned authority of Dhaka city water supply.

Figure 1.2: Peripheral Rivers around Dhaka City

1.2 Rationale of this Study

Water supply demand has shown that by the next 20 years, it will rise to a very high extent. This would be a major challenge to meet the demand of the future given the uncertainty of available sources. Presently, the four surface water treatment plants are in operation. These are Saidabad WTP Phase I; Chandnighat Water Works, Godnail and Sonakanda WTPs have a total installed capacity of 1630 MLD. The present production from these plants is around 500 MLD. The sources of raw water of these plants are the Buriganga and Shitalakhya Rivers. Over the years, water quality of these rivers and other peripheral rivers of Dhaka has deteriorated greatly due to discharge of untreated industrial effluent, domestic waste water and sewage. It was found that, 50-60% of total pollution load is from the industrial sources and 40-50% from domestic sources (DOE, 2016).

Although there is sufficient water in the peripheral rivers, but because of large scale pollution, the water of the peripheral rivers is no longer considered viable for a treatment plant in the long run. The Narayanganj WTPs (Godnail and Sonakanda) is planned to be expanded and rehabilitated to produce more water in coming years.This scenario is considered to be realistic, yet conservative as it assumes an increase in per capita consumption after rehabilitation of the network and a constant (and relatively high) per capita demand hereafter.

Dhaka city is experiencing groundwater recharge deficit every year. Moreover, increased rate of urbanization, illegal occupation, and encroachment reduce the amount and volume of surface water bodies around the city that deteriorate the present situation.

It is experienced that projected water demand is required 150 litres per person per day (lpcd). Empirical evidence shows that one-third of the city dwellers receive only 40 lpcd and they have to manage their daily activities with this little amount of water. Only 5.1 percent of total population of Dhaka city receives more than 60 lpcd. On an average, 42.8 percent of the respondents can receive basic requirement of 50 lpcd and the rest (57.8 percent) are suffering from water scarcity despite piped connection. A field survey of demand and supply has been shown in Figure 1.3.

≤ lpcd lpcd lpcd lpcd

Figure 1.3: Field Survey for Demand and Supply (DWASA, 2014)

Around 31.43 percent households in Dhaka city do not have access to piped connection and they have to rely on NGO or other sources (standpipe). Poor people, mostly living in the slum areas, are being neglected both at demand and supply side and are more deprived of having access to potable water. Despite little consumption, they have to pay more than middle-income or high- income group people. A poor household (whose total household income is less than 10000 BDT) has to

spend 500 BDT per month for 30 lpcd while a middle-income or high-income group family (whose total household income is more than 10000 BDT) has to pay 400 BDT/month for water supply of 45-50 lpcd or more. Poor people have to buy additional water to maintain their daily activities. This extra spending of water hinders to improve the livelihood status. Despite dominance of uncontaminated groundwater in DWASA water supply system, the user-end water quality exceeds World Health Organization’s (WHO) prescribed drinking water permissible limit due to poor maintenance. A study found that about 22.86 percent city dwellers could not use the DWASA supply for drinking purpose due to bad smell and have to rely on bottled or jar water that is of dubious quality. On the other hand, 66 percent of the consumers boil DWASA supplied water for drinking purpose and they have to boil the water at least for half an hour to make it potable. Among them, at least 50 percent also use water filter to ensure maximum safety (DWASA, 2015). Two- thirds of the Dhaka city dwellers believe that current water supply management system could not fulfill their demand. The present study has attempted to focus few scenarios considering existing water supply situation, future demand, water availability, water quality and finally cost effectiveness of surface water sources of Dhaka City up to 2035. It is apprehended that all of these scenarios showed a mismatch between water demand and supply.

1.3 Study Area

The study area encompasses area of present Dhaka city and planned future extension. The area is located within 90°47′ N latitude to 90°18′ E longitude. There are six rivers flowing along its periphery, notable of which are Buriganga, Shitalakhya, Balu, Dhaleshwari, Turag and Tongikhal. The study area covers about 617 km2 of Dhaka city as shown in Figure 1.4.

Figure 1.4: Map of Study Area 7

The existing Dhaka city service area covers approximately 497 km2 and includes some localities that are not mentioned in DWASA 1996 Act (parts Bandar Thana). The service area would expand to cover not only all of the existing jurisdiction area but also some neighboring locations in Madanpur and Dhamghar area. The study area is approximately 617 km2 covering following area as per Table 1.1. Figure 1.4 shows the study area with future extension in yellow shaded area beyond the red boundary Table 1.1: Study area coverage

Serial Region Area Coverage (km2) 1. Main Dhaka City 303 2. Tongi and Gachcha 61 3 Rupganj(Purbachal) 97 4. Bandar 36 5. Keraniganj and Kalagachia Approx. 120 Total 617

1.4 Brief Description of the Peripheral Rivers System

Dhaka City is surrounded by rivers in its periphery as shown in Figure 1.2. Buriganga, Turag, Balu, Shitalakhya, Dhaleswari and Tongi Khal engulf the City. The river Buriganga takes name as Buriganga from the end of Turag at Ameen bazar union of Savar upazilla, flows through the southern part of Dhaka city and meets Dhaleshwari River at Konda union of Keraniganj upazilla. The main flow of the Buriganga comes from the Turag only. The present head of the Buriganga near Chaglakandi has silted up and opens only during flood, but the lower part is still open throughout the year. Water pollution in the River Buriganga is at its highest. The most significant source of pollution appears to be from tanneries in the Hazaribagh area. In the dry season, the dissolved oxygen level becomes very low or non-existent and the river becomes toxic (Quader S, 2015). Shitalakhya River having a length of 113 km flows through Monohordi Upazilla of Norshingdi district and then east of the city of Narayanganj in central Bangladesh until it merges with the Dhaleswari near Kalagachhiya. The river joins the river Balu at Demra, a small tributary flowing from the north of greater Dhaka. About 20 km downstream of Demra, the Sitalakhya River joins the Dhaleswari River at the Bandar upazilla of Narayanganj district (BWDB, 2010). There are several different types of industries like textiles and dyeing, paper and pulp, jute, pharmaceuticals, fertilizers, etc of moderate to big size and several urban developments along the entire stretch of the river (Alam et al, 2012). These establishments contributed to the pollution load to the Sitalakhya River directly or through a number of wastewater canals like DND drainage canal Killarpul khal, 8

Kalibazar khal, Tanbazar khal etc. Domestic and industrial wastewater from Dhaka city through Norai khal and from the Tongi industrial area through Tongi khal disposed of in the river Balu. This also contributed to the pollution load to the river Sitalakhya. The water quality of this river is of particular importance for both the ecological and commercial reasons and for concerns regarding safe drinking water supply to the city as the largest surface water treatment plant in Bangladesh located at Saidabad draws water from it through the intake at Sarulia about 400 m downstream of its confluence with the Balu river. Balu River, a tributary of the Shitalakhy a River runs mainly through the extensive swamps of Beel Belai and those which are located at the east of Dhaka, joining the Shitalakhya near Demra. It has a narrow connection with the Shitalakshya through the Suti River near Kapasia and with the Turag River by way of the Tongi Khal. There is also a link with the Shitalakhya near Kaliganj. Although it carries flood water from the Shitalakhya and the Turag during the flood season, the Balu is of importance mainly for local drainage and access by small boats (Quader S, 2015). Tejgaon metropolitan area is an industrial area which dispose about 3 12000 m untreated waste per day (Roy, 2013) consisting of residue of soap, dyeing, pharmaceuticals, metals industries etc. Effluent of this industrial area is directly discharged into Begunbari and Narai canal which carries the waste through Balu River and ultimately flows on Sitalakhya River which is used in Saydabad water treatment plant for meeting water consumption demand of Dhaka city dwellers. Thus Balu river and its canal system in Dhaka east especially Narai canal is the most polluted area which is responsible for polluting Sitalakhya day by day and the ultimate outcome of this pollution is Saydabad water treatment plant’s being in threat. Turag River generates from Banshi River at Kaliakair and meets Buriganga at Kholamara of Keranjiganj. Turag is a narrow and short river originating as a side channel from the river Bangshi near north-western part of Gazipur and reaches Tongi. At Tongi, this channel divides into two, one flows eastward direction as river Tongi khal and then Balu while the other towards westward direction as river Turag. The river crosses Mirpur Bridge on Dhaka Aricha Highway at Amin Bazar and finally merges into Buriganga (Khondkar et al 2013).The Dhaleshwari River with a length of 160 kilometres is a distributary of the Jamuna River in central part of Bangladesh. It starts off the Jamuna near the northwestern tip of Tangail District. Dhaleshwari River divides into two parts after running a short distance from its generation point of Jamuna. The part which flows south takes name as Kaliganga and other which flows east takes name as Barinda, then it flows as Bangshi River (south) up to Savar. Then the same river again flows as Dhaleshwari through the southern part of greater Dhaka Zilla and finally the two flows merge to meet the Shitalakshya River near Narayanganj District. This combined flow goes southwards to merge into the Meghna River. At present a branch of Turag River, generating from the Birolia union of Savar Upazilla, flowing 9

eastward side of Tongi and meeting Balu River at Trimohoni of Uttarkhanupazilla is known as Tongikhal locally. A summary of the peripheral rivers has been shown in Table 1.2.

Table 1.2 : Summary of Peripheral Rivers River Name Length(km) Width(m) Originates Outfall Turag 21 218 Bansi Buriganga(Mirpur) River(Kaliakair) Tongi 14.4 60 Branch of Turag Balu River (Trimohoni) Balu 110 300 Turag(Amin Bazar) Shtilakhya (Demra) Buriganga 45 265 Dhaleswari(North) Turag Shitalakhya 110 113 Distributary of old Dhaleswari(Kalagachhiya) Brahmaputra Dhaleswari 160 300 Jamuna(Tangail) Upper Meghna Karnatali 40 55 Spill of Dhaleswari Buriganga river (Gabtoli) and Bansi River

1.5 Scope and Objectives of the Study

This study is conducted to determine the status of the present water supply system and its increasing demand of water supply in Dhaka city. Besides continuous pressure in ground water table during the last decade, it demanded to start operation of its su rface water treatment plants. From the inception of the SWTP operation the quality of raw water was found unsatisfactory in comparison with th e treatment strategy being implemented. Recently the intake water quality of the plant has been so much deteriorated, that’s why availability of surface water sources need to be worked out in details to meet the future demand of Dhaka city water supply .The specific objectives related to this research programme are: (i) To find out the future water demand for Dhaka city. (ii) To identify all surface water sources and their availability including the major rivers. (iii) To perform hydrodynamic modeling of available sources around Dhaka city. (iv) To perform water quality assessment of all available sources around Dhaka city including two major rivers named the Padma and Meghna. (v) To identify the suitable surface water sources in terms of cost effectiveness for the future water demand of Dhaka City.

1.6 Organization of the Report

The report is organized in eight chapters. In Chapter 1introduction of the thesis is outlined, in which the study area, importance and objective of the study has been discussed. The review of the literature is illustrated in Chapter 2 in which the previous study on water availability on ground water and surface water sources has been reviewed. In Chapter 3 data collection and the methodology of this study of water demand, quality, water availability and evaluation of surface water sources of the study have been described. Chapter 4 will make an effort to analyze the future population projection and future demand for the Dhaka city. In Chapter 5, water quality analysis of surface water sources of Dhaka city has been illustrated. In Chapter 6, the analyses of availability of surface water sources have been made. In Chapter 7, the evaluation of cost effectiveness aspects of surface water sources has been described. Finally, conclusions and recommendations have been summarized in Chapter 8.

CHAPTER TWO

LITERATURE REVIEW

2.1 Introduction

Dhaka is one of the most densely populated cities in the world, located in the central region of Bangladesh. The city is surrounded mainly by the distributaries of Brahmaputra-Jamuna and Meghna Rivers. These rivers are Buriganga, Dhaleswari, Balu, Turag, Tongi Khal and Dhaleswari. Apart from these peripheral rivers there are two main rivers Padma and Meghna are located adjacent to the capital city.

The flow characteristics of the rivers are mainly controlled by the upstream flow. However, low magnitude of tidal influence is observed at downstream of Balu and Buriganga River. Hydrologically response of the rivers due to rapid urbanization, filling of low lands and continuous population growth affecting the basin responses which, otherwise need to be assessed carefully. Moreover, it is also important to assess the impacts of different potential scenarios and different conditions. To meet the requirement of Dhaka city water demand, many analyses have been carried out in different aspects by many researchers. Mostly all works have been carried out related to ground water, surface water and water quality of peripheral rivers. Some of the review of earlier works is shortly explained in subsequent paragraphs.

2.2 Description of Water Quality Parameters

Water quality in the rivers and water bodies are affected by point and non-point pollution sources. However, the amounts and types of pollutants are not same from each source. As such, contribution of pollutants from both sources should be assessed for effective water quality management in river system. The point sources are outfall of pollutants from domestic, industrial and commercial areas. In the case of non-point pollution sources the whole study area contributes pollutants during flood events and rainfall runoff as per the land use and other conditions. To assess the present condition of water quality, sampling has been taken from different points of the river system. The primary objective of water quality monitoring is to obtain required information for decision making and management and obtaining useful information depends on correct interpretations of the measured variables in any water quality investigations. Water quality variables, river or stream hydraulics, and the aquatic living organisms are all interrelated and therefore interpreting the measured variables properly is vital for successful water quality

monitoring plan. In following sections description of some important water quality parameters have been briefly discussed.

Temperature of the water varies throughout the year and even throughout the day, but it will not vary as much as the air temperature. This is important to aquatic lives, because they are very sensitive to temperature changes. Temperature also affects aquatic life's sensitivity to toxic wastes, parasites, and disease, either due to stress of rising water temperatures or the resulting decrease in dissolved oxygen. Temperature and dissolved oxygen are closely related; the warmer the water, the lesser the dissolved oxygen.

Turbidity is one of the important quality parameter. Any substance that makes water cloudy will cause turbidity. The ability of light to pass through water depends on how much suspended material is present. The most frequent causes of turbidity in rivers are soil erosion from mining, dredging operations, and plankton. Erosion is a natural process which man speeds up by the use of unsound farming practices, by logging forest areas in an uncontrolled way, by failing to confine sediment runoff on construction sites. Rainfall causes a temporary increase in turbidity, although this is a very common condition in Bangladesh with specific rainy seasons. Turbidity affects fish and aquatic life by interfering with the penetration of sunlight. Water plants need light for photosynthesis. If suspended particles block out light, photosynthesis and the production of oxygen for fish and aquatic life will be reduced. If light levels get too low, photosynthesis may stop altogether and algae will die. It is important to realize conditions of photosynthesis in plants, increase respiration, oxygen use and the amount of carbon dioxide produced. Vegetation growth in the water will be limited due to the reduced penetration of the light. Large amounts of suspended matter may clog the gills of fish and shell fish and kill them directly. Turbid water absorbs more sunshine, raising the temperature of the water and lowering the amount of dissolved oxygen available for fish and aquatic life. Perhaps the most widespread problem throughout the world is sedimentation. From above description, it is apparent that the turbidity test should be done to know the quality of water.

Alkalinity is the water's ability to react with acids and neutralize their affect. Alkalinity protects aquatic life by buffering the pH of the stream to a tolerable level. Total Alkalinity of range 100 - 200 mg/l will stabilize the pH level in a stream. However, alkalinity values between 20 and 200 are usually found in natural stream.

pH is one of the most common water quality tests to be performed. pH indicates the sample's acidity, but is actually a measurement of the potential activity of hydrogen ions (H+) in the samples. pH measurements run on a scale from 0 to 14, with pH value 7 considered as neutral.

Solutions with a pH below 7 are considered acids. Solutions with a pH above 7, up to 14 are considered bases. All organisms are subject to the amount of acidity of stream water and function best within a given range. The pH of a body of water is affected by several factors. One of the most important factors is the bedrock and soil composition through which the water moves both in its bed and as groundwater. Some rock types such as limestone can, to an extent, neutralize the acid while others, such as granite, have virtually no effect on pH. Another factor, which affects the pH, is the amount of plant growth and organic material within a body of water. When this material decomposes carbon dioxide is released. The carbon dioxide combines with water to form carbonic acid. Although this is a weak acid, large amounts of it will lower the pH. This type of effect is often seen in eutrophicated waters and can, together with the variation in the daily oxygen content harm the fish population.

Organic pollution occurs when large quantities of organic matter reach a watercourse from sources such as sewage, agricultural sources, urban run-off and industrial effluents such as waste from food processing. The pollutants are a mixture of carbohydrates, fats and proteins and as such are easily digestible by the micro-organisms that naturally reside in the receiving water body. The bacteria reduce the amount of available oxygen in the water particularly in slow moving water. If the lack of oxygen in water is severe may kill the fish and other aquatic life. The effects on biota of organic pollution come from deoxygenation, toxicity and siltation acting either individually or in combination.

Phosphates enter waterways from human and animal waste, phosphorus rich bedrock, laundry, cleaning, industrial effluents, and fertilizer runoff. These phosphates become detrimental when they over fertilize aquatic plants and cause eutrophication. This process results from the increase of nutrients within the body of water which, in turn, create plant growth. Cultural eutrophication is an unnatural speeding up of this process because of man's addition of phosphates, nitrogen, and sediment to the water. Monitors should be aware that there are different kinds of phosphates in the water, but a total phosphate-phosphorous reading is all that is needed to calculate the water quality. If too much phosphate is present in the water the algae and weeds will grow rapidly and may choke the waterway. Further, the rapid production of plant material will lead to a large increase in oxygen levels in the daytime and a steep drop in the oxygen level during the night, when the plants turn from oxygen production to respiration. Nitrate in the water comes primarily from fertilizer runoff, leaky drains, and sewage discharges. In nature, they generally are formed by the action of bacteria on ammonia and on compounds, which contain nitrogen. Nitrite is a relatively short-lived form of nitrogen that quickly becomes converted to nitrate by bacterial activity. Nitrate reacts directly with haemoglobin in the blood of

people and destroys the ability of blood cells to transport oxygen. This condition is especially serious in babies under three months of age as it causes a condition known as methemoglobinemia or "blue baby" disease. Nitrate has the same effect on aquatic plant growth as phosphate and thus the same negative effect on water quality. The plants and algae are stimulated and grow and the plant material will provide food for fish. This may cause an increase in the fish population. But, algae overgrowth will reduce oxygen levels in the water during the night time due to the respiration of the algae and fish will die from oxygen related stress. Because nitrate can cause serious illness to both wildlife and humans, acceptable nitrate levels for drinking water have been established as 10 mg/l. Unpolluted water generally has a nitrate reading of less than 1.0 mg/l. Ammonia in the water comes from decomposition of organic material, from sewage treatment plants, and from scattered discharge of untreated human waste. It is also utilized by the aquatic + plants as a nutrient. Total Ammonia in water is a balance between the ionised (NH4 ) and the un- ionised (NH3) form. The pH and temperature control the balance leaving more ammonia at higher temperature and higher pH. The problem with the un-ionised NH3 is that it is very toxic to many species of fish and the level of toxicity is as low as 0.025 mg/L NH3. The change in pH of one unit is not uncommon in eutrophic waters and can easily happen within hours, when the plant growth is high.

Dissolved Oxygen (DO) in rivers varies considerably depending on many factors including temperature, presence of biodegradable organics and the aquatic living organisms. Dissolved oxygen gets into the water by diffusion from the atmosphere, aeration of the water as it tumbles over falls and rapids, and as a waste product of photosynthesis. Decreased DO levels may be indicative of too many bacteria (untreated sewage or other organic waste) which use up DO. Another reason for decreased DO may be nutrients flow from farm lands accelerating growth of aquatic plants. When the increased numbers of aquatic plants eventually die, they support increasing amounts of bacteria, which use large amounts of DO for the degradation of the organic matter. Large daily fluctuations in dissolved oxygen are characteristic of bodies of water with extensive plant growth. DO levels rise from morning through the afternoon as a result of photosynthesis, reaching a peak in late afternoon, photosynthesis stops at night, but plants and animals continue to respire and consume oxygen. As a result, DO levels fall to a minimum just before dawn. Dissolved oxygen levels may dip below 4 mg/l in such waters - the minimum amount needed to sustain warm water fish. The generally accepted minimum amount of DO that will support a population of various fishes is from 4 to 5 mg/l. When the DO drops below 3 mg/l, even the hardy fish die. Depletion in DO can cause major shifts in the kinds of aquatic organisms found in water bodies.

Due to rapid urbanization, industrialization, agricultural development, excessive population growth and upstream withdrawal of water have degraded the river water quality in Bangladesh. It has become essential situation for our country to conserve and protect our rivers from pollution. Despite of discontinuity in monitoring of surface water quality parameters, this analysis would shed some light on the present concentration of water quality parameters of the major river system of the country. Parameters like PH, DO, BOD, COD, Turbidity, TDS and Chloride were measured more or less round the year of 2014 for the spatial analysis and data for the last 10 years have also been collected to perform the temporal analysis. However, seasonality aspect of water quality and impact of industrialization on water quality surfaced up from the following analyses. Important drinking water quality standards (Ahmed and Rahman, 2012) are given in Table 2.1.

Table 2.1: Important Water Quality Standards

Bangladesh Standards WHO Guideline Serial Water Quality Parameters Unit (ECR 1997) Values (1996) 1. Ammonia (NH3) mg/L 0.5 1.5 2. Arsenic mg/L 0.05 .01

3. BOD5 at 20° C mg/L 0.2 - 4. Cadmium mg/L 0.005 0.005 5. Calcium mg/L 75 - 6. Chloride mg/L 150-600 250 7. Chlorine mg/L 0.2 0.5 8. Chloroform mg/L 0.09 0.2 9. Chemical Oxygen Demand mg/L 4 - 10. Coliform (Fecal) No/100 0 0 ml 11. Coliform (Total) No/100 0 0 ml 12. Color Pt-Co 15 15 unit 13. Dissolved Oxygen mg/L 6 -

14. Hardness (as CaCO3) mg/L 200-500 500 15. Iron mg/L 0.3-1.0 0.3 16. Lead mg/L 0.05 0.01 17. Mercury mg/L 0.001 0.001 18. Nitrate mg/L 10 50 19. Nitrite mg/L <1 3

20. Odor - Odorless Odorless 21. Oil and Grease mg/L 0.01 - 22. pH - 6.5-8.5 6.5-8.5 23. Phosphate mg/L 6 - 24. Silver mg/L 0.02 - 25. Sodium mg/L 200 200 26. Suspended Solids mg/L 10 - 27 Total Dissolved Solids mg/L 1000 1000 28. Tin mg/L 2 - 29. Turbidity NTU 10 5 30. Zinc mg/L 5 3

2.3 Quantification of Water Availability

2.3.1 Flow Duration Curve

Flow duration curve is a method of depicting the distribution of flows that occurs in a given river. The curve is generated by plotting the magnitude of every flow in the time period of interest in the y-axis, and the % of flows that equal or exceed that flow on the x-axis (hence the term: exceedance percentage). Flow duration curve has been developed for large and peripheral rivers to determine the 80% probability of water flow of that particular river. The water availability of the rivers was analyzed by flow duration curve.

2.3.2 Environmental Flow

Environmental flow means that water in rivers is managed in such a way that downstream users and ecosystems receive enough water for their sustainability. It entails negotiations between water users, based on an understanding that their water use has no effects on others, and on their natural environment. Environmental flow (e-flow) is required for the natural life of the river. This flow is essential within a stream to maintain its natural resources and dynamics at desired or specified level. Environmental flow assessment is required for balancing the use (or development) of water from aquatic ecosystems for various purposes whilst protecting (or managing) the aquatic ecosystems so that it can continue to be used by present and future generations. In a simple way, environmental flow can be defined as the water needed in a watercourse to maintain healthy ecosystems. In addition to the protection of a river, flows are needed to protect basic human needs and rights of downstream users, navigation, to prevent salinity intrusion and maintain channel diversity and flood carrying capacity (Acreman et al. 2004).

Environmental flow concept is at the core of all water management strategies for the river system in Bangladesh. Because, investigation on e-flow requirements for rivers of Bangladesh is essential in view of diminished flows and creation of dry beds in many rivers in lean seasons. The environment itself is increasingly being considered as legitimate water user in many countries. As a consequence the water requirement of the environment needs to be estimated. The amount of water that has been allocated to the environment is a decision made by society, and is to some extent arbitrary. Therefore, it has become essential to assess the e-flow for the sustainability of the peripheral rivers and major rivers to use a source of supply for Dhaka city. There are numerous methods available for the assessment of e-flows. The e-flow assessments (EFAs) are used as a method for estimating the quantity of water required. The e-flow requirement for a river is the minimum flow required to enhance or maintain aquatic and riparian life. More than 200 approaches have been used for determining e-flows in many different countries around the world. The most commonly used method is the Tennant method or Montana Method ( Brij Gopal,2010). This method is currently still the second-most widely used e-flow method in the world (Reiser et al. 1989). It specifically links average annual flow to different categories of environmental habitat condition. The Tennant method is based on discharge statistics and historical flows. The 10% flow requirement for a watercourse is expressed as a percentage of the mean annual naturalized flow at a specified site.

2.3.3 Use of Mathematical Model (HEC-RAS)

The mathematical model (HEC-RAS) developed by the Hydrologic Engineering Center (HEC) of the US Army, is a modeling platform for simulating steady and unsteady flow conditions, sediment transport (including mobile bed) processes and water temperature analysis. The HEC- RAS system is comprised of a graphical user interface (GUI), separate hydraulic analysis components, data storage and management capabilities, as well as graphics and reporting facilities. The basic computational procedure of HEC-RAS for steady flow is based on the solution of the one-dimensional energy equation. Energy losses are evaluated by friction and contraction/expansion. The momentum equation may be used in situations where the water surface profile is rapidly varied. These situations include hydraulic jumps, hydraulics of bridges, and evaluating profiles at river confluences. For unsteady flow, HEC-RAS solves the full, dynamic, Saint-Venant equation using an implicit, finite difference method. HEC-RAS is equipped to model a network of channels, a dendritic system or a single river reach. Certain simplifications must be made in order to model some complex flow situations using the HEC- RAS one-dimensional approach (HEC-RAS, 2010). It is capable of modeling subcritical, supercritical, and mixed flow regime flow along with the effects of bridges, culverts, weirs, and

structures. Currently, the steady and unsteady flow hydraulic analysis components of HEC-RAS are fully applied in practice. HEC-RAS model is therefore used to examine the scenario for the determination of water availability in this study.

2.4 Review of Water Supply Assessment in Various Countries

Lung W. S. (1986) developed a water assessment model for the upper James River to quantify effect on growth of phytoplankton by phosphorus and other factors and to determine the impact of point source phosphorus load reduction on biomass level. Variables considered in his model are CBOD, DO, organic nitrogen, ammonia nitrogen, nitrite/nitrate nitrogen, algae and phosphorus. Both BOD/DO kinetics and phytoplankton/nutrient dynamics are included in the model. Calibration and verification reveal the few decisions. Light limitation causes unfavorable conditions for algal growth which result in significant decline of phytoplankton biomass. DO profile shows moderate depression below Richmond which is associated with BOD load from point source and increase in algal photosynthesis. The lower level of orthophosphate in the James River Estuary is about 0.01 mg/L of P, which is much higher than the limiting value of algal growth. Phosphorus is not the key factor which limits phytoplankton growth in the river. Turbidity, light, mean depth and all other factors govern in limiting phytoplankton growth in James River Estuary.

Model projection indicated that reduction of phosphorus load from municipal waste water treatment plant to levels that limit phytoplankton growth would facilitate the control of phytoplankton biomass to reasonable and manageable levels. Modeling the phytoplankton kinetics in relation to other system variables such as DO, CBOD, N, P, as well as light extinction coefficient in the present study is expected to be performed in a similar approach adopted in this paper. In addition, policy as well as waste management issues in the current study may be addressed in a fashion similar to that adopted by Lung W.S. (1986).

Badruzzaman, A. B. M. and Lung W. S. (1991) developed a 3-D multilayered time variable model to assess the temporal and spatial distribution of dissolved and particulate Cu (II) in water and sediment layer. The author mentioned that a significant amount of pollutant have been introduced into New York Bight for past 30 years. These are originated from transact zone which includes New York metropolitan area, Northern New Jersey and Hadson river drainage basins which causes accumulation of Cu(II) in water and sediment layer. Their model incorporates the physical process of advection-dispersion and settling, chemical processes of sorption,

precipitation, speciation and bio-uptake. The model developed in their study includes two sub models one deals with transport fate and the other addresses metal chemistry.

In the model the water column is considered to be divided into 02 layers to represent seasonal stratification in which less dense water from Hadson-Raritan estuary flows outward through the upper layer and dense Bight water flows through the lower layer. The advective-dispersive transport of Cu (II) is handled by the WASP and a kinetic submodel is structured to handle the kinetic transformation processes such as adsorption, bio-uptake, bio-turbulation and sediment burial. From the schematic representation of the processes involved in Cu(II) distribution, there were the few conclusions. The aerobic sediment layer is considered to have diffusive exchange of dissolved Cu (II) with both overlying water column and the underlying anaerobic sediment layer. The particulate exchange in the water column is a function of advection and dispersive transport and loss due to settling. The top sediment layer is assumed to have no accumulation or loss of particulate. The bottom layer of sediment is assumed to receive the settling solid particulate from water column and suffer due to particulate leaving the layer through sedimentation. The model developed was run with different sets of data and they were well reflected by the model which shows the following results. A seasonal rise and fall of metal concentration occur in the water column. Initially more accumulation of Cu (II) in the sediment layer, but after some time, bio- turbulation mixing causes more polluted particles to be brought into the top sediment layer from the bottom layer and dissolved Cu (II) in the same layer increased because of Metal diffusion.

Sensitivity of their model is also tested by varying different key parameters such as settling velocity, loading and vertical diffusion coefficient. Decreased concentration of particulate Cu (II) in the water column and increased concentration of particulate Cu (II) in the sediment layer occurs because of doubling the settling velocity. Increased concentration of both dissolved and particulate Cu (II) in the water column and no change in the sediment layer occurs because of doubling the load. The reason behind this is that the water column reaches equilibrium much faster than sediment layer.

When vertical diffusion decreased to 1/10th of its initial value between the surface and bottom layer, the dissolved Cu(II) diffused into the bottom water layer and remain entrapped there increasing concentration. The study also shows that chemical speciation of Cu (II) is depended on its concentration in water and sediments and at low concentration, only one species dominates. At higher concentration, chemical reactions produce species reducing the dominance of one species.

Bongartz et al. (2007) dealt with water characterization (assessment) and load-reduction impacts evaluation (modeling) of stream water quality data in the Saale River basin, Germany. For a period of 6 years the data which was sampled by government environmental agencies was investigated to assess indicators and sources of pollution. The investigation has shown that some selected water quality parameters can be used as catchment specific indicators for different kinds of pollution and differentiate between human made and natural sources. Thus, management measures which are required by the European Water Framework Directive (WFD) can be applied according to the specifics of the various sub-catchments with pollution hotspots. The assessment of sources of pollution via a modeling (using WASP5) exercise of the routing of different pollutants was made in the lower part of the basin. The modeling was done to evaluate not only the sources of the pollution but also the distribution and the accumulation within the stream network. The method used to analysis the load-reduction impacts in this paper may be adopted to conduct similar analysis in the current study.

Liao and Xu (2008) hydrodynamic and water quality models of Suzhou Creek were developed. Based on models, the impacts of the upstream input and local pollution loads were analyzed. The water quality of Suzhou Creek was predicted based on the assumption that the upstream quality was improved by one class and the tributary quality met Class V of the National Surface Water Quality Standards. The relative ratios of tributaries meeting Class V to upstream improvement for the water quality improvement of Suzhou Creek were also computed. From the above analysis, the authors drew the few conclusions. The change of the water quality of upstream input impacts more on the upstream segments of Suzhou Creek than the downstream segments. Among all monitoring parameters, DO is most sensitive to this change. On average, the local pollution loads impact the water quality of Suzhou Creek slightly more than the upstream input.

2.4.1 Water Demand Management in Srilanka Srilankan water management strategies are recommended by several studies as follows:

a. Per capita consumption to be reduced from 145 lpcd to 120 or 100 lpcd by tariff itself. b. Rainwater harvesting for urban users. c. Promotion of alternative water uses- recycling of wastewater from industrial sector and use of separate system for gardening etc. d. Creation of awareness among users e. Public Participation

2.4.2 Water Supply Management in India Water scarcity is a prime issue in Dwarka municipality in India. Dwarka district is in the Gujarat state in north-western India. Dwarka is getting around 25% of their demand from the Delhi Development Authority (DDA). So there is huge demand supply gap. In order to cope with inadequacy of service utility, several strategies have emerged at the individual and community level. Some of these strategies are discussed are follows:

a. The authority offered linear solution, withdrawing increasing volume of water and discharging waste at ever increased levels. It caused escalating stress on receiving environment. This approach is towards increasing the quantity of supply. b. To make water management sustainable urban water management must integrate a larger proportion of solutions like raising awareness to reduce consumption, law enforcement and controls, reuse and recycling of storm-and wastewater, and climate change adaptation. c. Raising awareness on water risks, efficient water used through the stakeholders’ involvement in water management. Identification of key actors and their role in water management must be investigated for sustainable water management. d. The development control, policies, laws enforcement situation must be investigated. The estimated breakup of the per capita water demand clearly shows that 40% of the domestic demands in Delhi need not to be potable water and recycled greywater can be used which can be applicable for Dwarka also. The Central Groundwater Authority made it mandatory for buildings (for plot area 100 m2 or more) in Delhi to make provision for rainwater harvesting. The byelaw is applicable for Dwarka also; however the implementation of the same is not being monitored by the government concerned agencies and its technological appropriateness and maintenance is doubtful. e. The Delhi Government has modified the building byelaws (GOI notification 28 July 2001) to promote reuse of wastewater in buildings where daily wastewater generation is 10,000 litres or more. DDA initiated use of dual water supply systems in Dwarka in 2002-03 to promote the reuse of rainwater and recycled wastewater. f. The Master Plan for Delhi 2021 has also emphasized the recycling of treated wastewater through dual supply systems, however, these concepts have not been implemented in Dwarka until today. Government agencies also have not taken any action to implement the act because they are not clearly aware of the technicalities for the system. The area has been notified which means no groundwater extraction is permitted unless approved by the Central Water Government Authority. However, it is a known fact that there is rampant illegal boring in the area.

g. The National Water Mission has given emphasis on the water use efficiency, exploring the option to augment water supply in critical area, this mission strategies also include studies on the management of surface water sources, management and regulation of ground water sources, upgrading storage structures for fresh water and drainage systems for wastewater, conservation of wasteland and development of desalination technologies. The National Mission on Strategic Knowledge for Climate Change tends to identify the challenges of and the response to climate change through research and technology development. Applicability of these missions’ strategies for Dwarka is necessary for sustainable water management.

2.4.3 Water Management in Nepal

This large scale wastage of the surface water flow is true in Nepal because out of 225 billion cubic meter of annual surface flow, only 2% is utilized in the country and the rest drain down to Indian plain passes through the large Gangetic plains of India and enters Bangladesh before it finds drain down to the Bay of Bengal and join the sea. On the other hand, acute water shortage is being felt in several part of the country. It is therefore imperative to develop additional storage in the country to reduce this wastage to as low as possible. Nepal consists of about 80% of the mountainous area, the rest being plains and lowland. It consists of the three roughly parallel strips namely the northern region of the high mountains, central region and the southern region of Terai. Nepal is under the general influence of the sub- continental climatic pattern. It has two distinct seasons. Different water resources available in Nepal are summarized below:

a. Depending on the sources of the discharge, the rivers of Nepal are of three grades. The first grade rivers are the Karnali, Narayani and the SaptaKoshi along with their tributaries, having their sources in the snow and glaciers in the Himalayan Region. There are about 6000 rivers in Nepal. 1000 of which are more than 11 kms long and about 100 of them are longer than 160 kms. The total length of all streams and rivulets exceeds 45,000 km. b. Although ground water resources are still under investigation in Nepal, so far the most prospective sites of the ground water resources lying mostly in the Terai and in some mountainous valleys as well. Static water tables of the aquifers lie normally between 3 to 10 m from the ground surface in the eastern and Central Terai with yield between 100-300 cu m/hr. c. There are innumerable lakes and ponds, covering about 2% of the total runoff. Most of the oxbow lakes are found in Terai. There are several hot springs known as " Tatapani" and similarly hot suppurated water exists about 1 km south of kowaris check post in Sunkoshi valley. In Janakpur also there are three hot springs containing sodium, potassium,

sulphate, carbonate and chlorine ions. Water is mainly used in Nepal for the agricultural domestic, industrial and the commercial purposes. About 80% of the people in Nepal are engaged in Agriculture. Due to the shortage of water problem, in drinking water, for domestic use, for the irrigation, fisheries hydro power, industrial work, infrastructure development and ultimately affected the human existence. The activities like discharging domestic sewage & sludge, industrial effluents, agricultural chemicals and the solid wastes, encroaching riverbank for illegal settings, pig farming, vehicle repair and slaughter of animals, all these contribute to the pollution of water resources and poor water quality. To utilize the natural resources for the maximum benefit of the human being it is essential that proper managing of the natural resources should be made. d. One way to manage water resources is to increase the supply in a particular area by building dams & reservoirs, bringing in surface water to form another area or tapping ground water. Another approach is to improve the efficiency of the water use. Solutions adapted by Nepal to restore the available water resources and managing water can be discussed in following points: e. Huge dams and reservoirs have benefits & drawback, water from rain & melting snow can be captured and stand in large reservoirs created by damming streams. This water can then be released to produce hydro-electric power at the dam site, to irrigate land and to provide water carried to towns and to provide water carried to towns and the cities by the aqueducts. Reservoirs are also can be used for the recreation activities such as swimming, fishing, boating. f. Groundwater should be tapped for the solving water problems. Ways to slow groundwater depletion include controlling population growth, not planting water- thirsty crops in dry areas, developing crops strains that require less water & wasting less irrigation water.

2.4.4 Surface Water Management Plan (SWMP) in London

London has a SWMP with the purpose of sustainable surface water management decisions that are evidence based and risk based, whilst taking climate change into account, and are inclusive of stakeholder views and preferences. The framework for undertaking a SWMP study is illustrated through a wheel diagram, identifying the four principal phases: Preparation; Risk Assessment; Options; and Implementation and Review. The first three phases involve undertaking the SWMP study, whilst the fourth phase involves producing and implementing the action plan, based on the evidence gained from the SWMP study. It was based on a widely adopted generic approach to evidence and risk based decision making (Arthington et al. 1998). The phases are summarized as follows:

a. The first phase of a SWMP study focuses on preparing and scoping the requirements of the study. Initially, partners and stakeholders should identify the need to undertake a SWMP study. The aims and objectives of the study should be established, and in parallel the partnership will also decide how they will engage with stakeholders throughout the SWMP study. An assessment should subsequently be undertaken to identify the availability of information. Based on the defined objectives, current knowledge of surface water flooding, and the availability of information, partners should agree the level of assessment at which the SWMP study should start. b. The outputs from the preparation phase will identify which level of risk assessment will form the first stage of the SWMP study. The first stage is likely to be the strategic assessment where little is known about the local flood risks. The strategic assessment focuses on identifying areas more vulnerable to surface water flooding for further study. The intermediate assessment, where required, will identify flood hotspots in the chosen study area, and identify quick win mitigation measures, and scope out any requirements for a detailed assessment. A detailed assessment of surface water flood risk may be required to enhance the understanding of the probability and consequences of surface water flooding and to test potential mitigation measures in high risk locations. Guidance is provided on undertaking modelling to support a detailed assessment of surface water flood risk and mitigation measures. The outputs from the strategic, intermediate and/or detailed assessment should be mapped and communicated to all stakeholders including spatial planners, local resilience forums, and the public. c. In this phase a range of options is identified, through stakeholder engagement, which seeks to alleviate the risk from surface water flooding in the study area. The options identified should go through a short-listing process to eliminate those that are unfeasible. The remaining options should be developed and tested using a consideration of their relative effectiveness, benefits and costs. The purpose of this assessment is to identify the most appropriate mitigation measures which can be agreed and taken forward to the implementation phase. d. Phase 4 is about preparing an implementation strategy (i.e. an action plan), delivering the agreed actions and monitoring implementation of these actions. The first step is to develop a coordinated delivery programme. Once the options have been implemented they should be monitored to assess the outcomes and benefits, and the SWMP should be periodically reviewed and updated, where required. In Figure 2.1 shows the diagram connecting the coherence in plans and policy.

Figure 2.1: Diagram showing the coherence in plans and policy (Arthington et al. 1998)

2.4.5 Surface Water Management Plan in New York, USA

The Bureau of Water Resource Management works to protect, manage, and conserve New York State's groundwater and surface water supply sources, develop management strategies to enhance and protect these waters, and protect both the groundwater and surface water quality in the New York City Watershed and other major watersheds (Deniz et al. 2004).

a. The Bureau's work includes programs for public water supply permitting, which includes analysis and approval of aquifer (pump) tests and reservoir capacity; drought management; Great Lakes water withdrawal registration; statewide water withdrawal reporting; groundwater; interstate water supply partnerships; reservoir releases; water conservation; and water well drillers registration. The Bureau provides geotechnical assistance to local, state, federal, and industrial/commercial entities, and has partnered with the U.S. Geological Survey (USGS) for over 25 years to conduct a cooperative statewide aquifer mapping program. b. The Bureau also manages DEC's water quality and watershed protection programs for the New York City water supply system, including Federal Safe Drinking Water Act grants, compliance for SPDES permits within the watershed, and technical assistance and training for wastewater treatment facility operators within the watershed. c. The Bureau works with stakeholders and partners to improve water quality, provides funding for Water Quality Improvement Projects, and conducts outreach and communication activities. The Bureau's responsibilities also include developing and managing a geographic information system (GIS) that provides information and data 26

about New York State's waters. d. Bureau Sections includes four sections as: . Water Quantity Management Section . New York City Watershed Section . Watersheds Program Coordinator . Non-Point Source Section

2.5 Water Supply Scenario in Different Cities

Water supply circumstances are diverse for various cities and countries. Different cities possesses different scenario regarding water supply. The scenario reveals an impression that average number of person per connection is more in Dhaka than other cities as shown in Figure 2.2 as well as Table 2.2.

250 Average number of persons per connection

Percentage with 24-hour supply ) 200 Per capita consumption (lcd)

150

100

50 WaterConsumption(lcd

Figure 2.2: Water supply scenario in different cities

Table 2.2: Water supply scenario in different cities City Average number of Percentage with Per capita persons per connection 24-hour Supply consumption (lcd) Dhaka 30 0 117 Kathmandu 10.5 0 69 Manila 9 97 127 Ho Chi Minh 8.75 75 168 Jakarta 7.5 90 76 Phnom Penh 7 100 104 Colombo 6 60 119 Vientiane 6 50 112 Delhi 5 1 109 Karachi 5 0 198

2.6 System Loss in Different Cities

System loss is a serious issue in water supply sector. It may not be stopped but it can be minimized. System loss is also prevailing in other countries. However for the Dhaka city the system loss is quite similar to the other neighboring countries (Lung, 1986). Necessary steps must be taken to reduce the system loss to make it more rational. As for examples, system loss in percentage in some cities of neighbouring countries is shown in Figure 2.3.

30%

Systems loss 25% 20% 15% 10%

System System loss in % 5% 0%

Figure 2.3: System loss in cities of neighboring countries

2.7 Review of Studies on Surface Water Quality of rivers around Dhaka City

Many works have been conducted on the surface water sources of rivers around Dhaka city. Reviews of some of the recent studies on surface water sources from Padma, Meghna and peripheral rivers around Dhaka city works have been performed. Haque A (2014) in his article reported that water management in Dhaka city has become a megacity with a population of nearly 15 million, which is increasing at an annual rate of over 5%. Industrial, domestic and commercial wastes are polluting surface water, and groundwater in certain areas of the city also shows signs of both organic and inorganic contamination. Laws to prevent environmental pollution are rarely enforced. Overall service delivery considered to be poor due to an inadequate tariff structure, high non-revenue water, lack of authority and commitment, inadequate management capacity, lack of sector coordination, inadequate investment, absence of effective decentralization etc. He also focused that the situation could be improved by higher investment, effective private sector participation, improved billing and revenue collection, structural reforms, establishing a regulatory body and finally converting DWASA into a truly service oriented commercial organization. The performance of DWASA needs to be improved to meet the millennium development goals. He also mentioned that millennium goals can be achieved by reducing the population without access to water supply and sanitation services by 50% by the year 2025.

Karim et al. (2000) carried out field monitoring and laboratory measurement of water availability and quality of the lower reach of the peripheral rivers for the month of January to April. He applied 1-D WASP (Water Quality Analysis Simulation Program) by the USEPA with the collected data to quantify the state of pollution and the assimilative capacity of the river for dry weather condition. It was reported that the DO condition of the river water remains above the critical level of 4.0 mg/L, supporting the survival of aquatic life including fish. He found that the river had significant assimilative capacity and can assimilate the waste load from future new industrial establishment without violating the DO standard under prevailing flow condition. However, some water quality parameters like total nitrogen and suspended solids would remain very high and cause a potential threat to the aquatic life. He stressed that necessary management, control of projected waste loadings and ensuring current river flow must be formulated to support balance aquatic life and increased river assimilative capacity. His study revealed that phytoplankton growth in the river is highly suppressed due to the lower level of light penetration caused by high turbidity in the water column.

For the feasibility study of Saidabad Water Treatment Plant, IWM (2004) analyzed the water quality data of Sitalakhya and the Balu river. Water samples were collected from 4 locations along the Sitalakhya river from Ghorasal to the Sarulia intake point during high tide to obtain an idea about the distance to which the polluted water from the Balu-Sitalakhya confluence travels upstream during high tide. The water samples test results showed high contents of ammonia upto around 3 km from the confluence. Based on available data they found that the Balu river with very low DO and high coliform values, especially during the dry season, appears to be more polluted than the stretch of the Sitalakhya river. The main concern for the Saidabad water treatment plant during the dry season is the high concentration of ammonia and algae in the intake water. To find out an alternative location, they also analyzed Majhina about 1 km south of Rupganj ferry-ghat for projected BOD loadings. BOD loadings were estimated for the years 2000, 2005, 2010, 2015, 2020 and 2025. Model results showed that DO level increases from the Sarulia intake towards upstream direction. DO level at Sarulia intake point goes down to 1.0 mg/L for 2002 loading and it further goes down and reaches to 0.67 mg/L for 2025 loading conditions. The DO level near village Atabo (1 km u/s of Rupganj Hospital) remains always above 4.0 mg/L for all loading conditions. DO level at proposed intake location goes down to nearly 3.0 mg/L for 2025 loading condition. They concluded that there was no significant deterioration in DO level from the Majina location which was more preferable than Atabo.

Ahmed, T. (2005) investigated the effects of thermal discharges in the Sitalakhya River from the existing and proposed thermal power plants in the Siddirganj area. The CORMIX model was used for prediction of thermal plume for discharges of Siddirganj and Globeleq power plant under different tidal conditions of the river during the critical dry period of the river. Water quality simulation results of some parameters such as BOD, DO, ammonia, nitrate, phosphate was carried out for existing conditions of the river. Sensitivity analysis was performed to assess the impact of excess temperature caused by the thermal effluents from the power plants. The results of the analysis showed a small decrease in BOD and ammonia, a small increase in nitrate and a significant decrease in DO (about 0.5 mg/L) due to excess temperature.

Majumder, T. K. (2005) overviewed contamination scenario of the peripheral river system around the Dhaka city including historical trend of the pollution. It was observed that required DO for sustaining aquatic lives (4 mg/L) prevails only in the Dhaleswari River and in a very short downstream reach of the Sitalakhya River throughout the year. The rest of the river reaches maintain lower DO level, usually less than 1 mg/L, in the dry period. Ammonia level in different reaches of the river system is well above the permitted value in the USEPA guideline to avoid toxic effect on fishes. Concentrations of Nitrate, Phosphate, Zinc, Chromium, Lead and Mercury in the river system are well below the allowable limits specified in different Environmental Quality Standards (EQS).

The study findings highlights that it is essential to make provisions for improving water quality in the peripheral rivers to sustain the city water supply system, the ecosystem in the rivers and, above all, the overall environment of the capital city. Further detail study carried out by IWM (2006) to assess the water of the major rivers with special reference to the intake point of Saidabad water treatment plant. Following results have been found from the analysis:

a. Water quality at the intake point at Sarulia is highly polluted. The DO level in present condition (0.6 mg/L) was far below the critical DO level (4 mg/L) and it continued to decrease with increasing waste load in future. The water quality of Sitalakhya river in the upstream of Sarulia was much better and at 7.5 km upstream it was very close to the critical DO value. b. The Norai khal, which falls into the Balu river at 5.5 km upstream of the Balu-Sitalakhya confluence, is chiefly responsible for deteriorating the water quality of Balu river. Norai khal effluents also affect the water quality at Sarulia as Sarulia is only 400 m downstream of the Balu-Sitalakhya confluence.

c. In addition to Norai khal, DND khal, Majheepara khal, Tanbazar khal, Killarpul khal, Kalibazar khal and B.K. Road khal from Narayanganj area are identified as the major pollutant sources affecting the water quality at Sarulia. d. On the basis of their analysis, finally they recommended that of the state of water quality major sources should be treated before their disposal to rivers.

Department of Environment (DOE, 2016) assesses the surface water and ground water resource throughout the country almost every year. The main objective of the campaign was to investigate the existing condition of the water bodies in Dhaka city. Water quality of peripheral rivers of Dhaka was measured at different sampling stations in the year 2010. The sampling stations of DOE are located at different locations of peripheral rivers. The main objective was to create a database of water quality of peripheral rivers around Dhaka city. Following Table 2.3 shows the state of water demand against the population and the amount of deficit occurs in percentage (DWASA, 2014). It represents that the deficit gradually increases with the increase of population and demand.

Table 2.3: Population, water supply and demand for various years Year Population Water Demand Water Supply Deficit (%) (millions) (MLD) (MLD) 1963 0.85 150 130 13

1970 1.46 260 180 30 1980 3.03 550 300 45

1990 5.56 1000 510 49 1996 7.55 1300 810 38

1997 8.00 1350 870 36 1998 8.50 1400 930 34

1999 9.00 1440 1070 26 2000 9.50 1550 1130 25 2001 10.00 1600 1220 24

2002 10.50 1680 1300 23 2003 11.00 1760 1400 20 2010 12.27 2485 1500 40

2020 18.04 3680 1500 59

2.8 Review of Previous Studies on Groundwater Quality

As stated earlier 78% of Dhaka city water supply is dependent on ground water sources. However, ground water sources are at the verge of contamination as reported by many reseschers. The outcomes of the works are summarized as follows:

There are around 702 DTWs in the upper and lower aquifer of Dhaka city. Every year the groundwater level is depleting at a rate of 2‐3min the upper dupitila aquifer. A study by IWM that the rate of mining of the upper dupitila aquifer is around 14‐15% and the potential of exploitation of the lower dupitila aquifer is limited. Therefore, the groundwater aquifers are no longer sustainable in the long‐term identification and utilization of alternative sources to groundwater is very important to meet the water demand of Dhaka City (IWM, 2014). A project is being carried out by DWASA which will bring 300 MLD of groundwater in two phases from a well field in Savar and Singair Upazilla. The most critical period of the year is March in terms of water availability and water quality for the surface water sources. Therefore assessment of water availability was made based on historical simulated data from March. It was found that withdrawal for water supply from the peripheral Rivers would not result in any major change in water depth. But the water quality is progressively declining due to increase in pollution load from various domestic and industrial sources. The situation would further deteriorate if no pollution control measures are implemented. Therefore, the peripheral rivers as water supply sources for Dhaka city are considered vulnerable. Water availability analysis in the major rivers is show that they have significant flow available. The water quality of these rivers is also acceptable. The feasibility studies of the Gandharbapur SWTP and Saidabad Phase‐III found abstraction of 2525 MLD water is viable from Meghna River. The feasibility studies of Jashaldia SWTP found abstraction of 900 MLD is viable from Padma River. These sources have been found to be technically and economically feasible in the long‐term for Dhaka City. Additional analysis has been done for resource assessment periods 2035 to 2060. The availability of suitable water from the Meghna River for additional use has some uncertainties. However, the Padma River should be a reliable source. Protection from pollution is required if peripheral rivers are to be considered for future supply.

Based on the monitoring and chemical analysis of samples from groundwater wells (both HTW and DTW) all over the Dhaka city a general trend of increasing groundwater pollution has been identified from north to south of the city. The wells near the Buriganga River has been found to - -2 - have very high concentration of Cl , SO4 and NO3 while these are present in very small quantity in the wells in the northern part of the city. Presence of considerably high quantity of these three

ions in the wells near Buriganga suggests infiltrating surface water may contaminate the groundwater. A zone of relatively elevated groundwater Electrical Conductivity (EC) is apparent in the southern part of the city and this has migrated progressively towards north from 2012 to 2014 (Hasan et al. 2014).

Ahmed et el. (2012) conducted a study for the assessment of ground water quality on the Jatrabari area, waste dumping site. He showed that a significant depth variation in groundwater EC. The HTW water is characterized by high concentration of dissolved ions including Cl- than the DTW water. Industrial effluent dumping sites; the Begun Bari khal at Tejgaon, Dholaikhal at Dholaikhal engineering workshop area, Hazaribaghkhal and Buriganga at Hazaribagh tannery are causing groundwater pollution. The impact of effluent and polluted river water is more pronounced in shallow groundwater (<100m) as compared to deep groundwater. EC of shallow groundwater well at Hazaribagh was 1000 S/cm whereas the EC of DWASA production well was 650 S/cm.

An assessment of groundwater contamination by (Karim et al. 2000) revealed that higher concentration of chromium had been detected in the samples from Zone 2 compared to other DWASA zones where tannery was located. It is also reported that the average chromium concentration of the 14 water samples from Zone 2 is 0.036 mg/l and the concentration varies significantly with time. As no natural source of chromium is present, chromium rich tannery wastewater appear to be the most likely source of chromium in groundwater. But the seasonal variation of chromium is not clear. Apart from chromium, alarmingly high lead concentrations were found in many DWASA groundwater samples of Zone 2. Most of the samples exceeded WHO guideline value for drinking water (0.01 mg/l). This is a serious health concern and should be addressed immediately. It also reveals that significant levels of Sulphide is also detected in samples of Zone 2 but not detected in the samples from other zones except in few from Zone 4. It also appears that the tannery wastes are responsible for high sulphide concentration. Literatures reviewed on groundwater quality of Narayanganj area reveals the state of groundwater quality of the Narayanganj area in the recent years and the possible causes of groundwater deterioration. High groundwater EC values (1000 to 2900 S/cm) detected in the central and southern part of the city, close to Sitalakhya River shows marked vertical variations in groundwater quality. Shallow groundwater has higher dissolved solids, which demonstrates contamination in the upper aquifer. Several heavy metals: As, Pb, Mn, Cd are found to occur above the Bangladesh and the WHO drinking water standards in a number of samples tested. Highest concentration found was 0.075 mg/l at a HTW in Kadamrasul area of the town. The possible causes of groundwater quality

deterioration for the Narayanganj area other than arsenic are Industrial contaminants, land filling with municipal wastes, discharge and leakage from open drains and septic tanks.

2.9 Deep Tube Wells Operated by Private Agencies

At present around 1846 DTWs are operated by private agencies (DWASA, 2016). Commercial and industrial sectors are the major stakeholders of this group. DWASA does not have any statistics on the actual water extraction through these DTWs (Serajuddin, 2014). It is identified as a grey area of the overall water supply system of the city. A lot of steps were taken to explore the water consumption data of the garment industries alone. From BGMEA it was found that, at present total 1600 garment factories are operational in the city. The average water consumption to produce a finished 1 kilogram knitwear and woven product is around 115 liters and 130-140 liters respectively. From Export Promotion Bureau it was found that, total 508.67 million pieces of knitwear and 484.95 million pieces of woven products were exported during the year 2013-2014 (Bhuiyan, 2014). No data in terms of volume or weight of the total production is available with any of the organizations. As a result, correlation between water consumption and total production was not possible and no conclusive remark could be made on total water consumption. However, it is perceived that, huge amount of groundwater is extracted by these types of users which need to be identified and monitored for sustainable and efficient planning.

2.10 Relevant Studies of Dhaka Water and Sewage Authority (DWASA)

DWASA collected water sample from peripheral rivers and analyzed water quality parameters in their laboratory. They observed that most of the water quality parameters are quite higher than the guideline value. Thus the surface water quality was not found suitable for both domestic and agricultural use with a very little exception like Dhaleswari and Shitalahkya river throughout the year.

Institute o f Water Modeling (DWASA, 2014) conducted feasibility study for the rehabilitation of Buriganga-Turag-Shitalakhya river system and for the augmentation of dry season flow in the Buriganga river. The study suggested that the project will take long time to implement and thus not cost effective. Rahman S (2005) made a study on water quality parameters of peripheral rivers of Dhaka city. From the study, it was found that rivers were not suitable as a source of water supply for Dhaka

city in the dry season. However, in wet season the water quality parameters were found satisfactory. BWDB reviewed surface water quality data of peripheral rivers of Dhaka with their 17 sampling stations and their altogether 38 sampling stations of different organizations including DPHE, and DWASA. The y concluded that surface water quality in most part of Dhaka is not suitable for all uses (BWDB, 2009). At that time they gave aesthetic issue of iron, chloride, TDS and hardness. There review neither reported to show its suitability for domestic purpose.

Institute of Water Modeling (IWM, 2005) carried out an investigation on the water quality of Shitalakhya river at the locations adjoining the Saidabad Surface Water Treatment Plant (SWTP) in 2005. The report is focused on the water quality of Shitalakhya river close to the intake point of Saidabad Surface Water Treatment Plant (SWTP) to justify whether the intake point is in suitable location for water supply or not. The report found out that the intake point is in the suitable location.

Considering the existing groundwater situation, DWASA is making a strategic effort to build more surface water treatment plants (SWTPs). Currently, there are 4 SWTPs in operation. Sonakanda SWTP is currently being rehabilitated and the new plant will have 12 MLD capacity. Godnail SWTP is currently production 18MLD but after renovation works it will have 45 MLD treatment capacity. Chandnighat SWTP has a capacity of 39 MLD after renovation work but produces 1 MLD on an average during dry seasons due to low water levels in Buriganga River. Even the treated water at the plant cannot meet the WHO and Bangladesh standard due to poor intake water quality. In fact, all four SWTPs suffer this problem. Of the existing 4 plants, Saidabad SWTP Phase-I plant is the largest and it has been operating since early 1990s, while Phase-II plant became operational in December 2012. The objective of 1 bar pressure at the farthest point of the main is yet to be realized. Godnail and Sonakanda SWTP Transmission Main is currently undergoing rehabilitation (35km) and 60 km new mains of diameter 150 mm to 800 mm are being constructed. New primary and secondary distribution mains for the proposed SWTPs will also be required.

The network suffers from lack of proper planning, ageing fixtures, poor material and poor workmanship. The system also suffers from illegal connection and pilferage. The District Metered Area (DMA) program plans to rehabilitate and replace the existing distribution network. DMA is designed to be a 24 hr pressurized system that will source water from local DTWs and SWTPs i.e. conjunctive usage. However, given the uncertainty associated with DTW supply due to

mechanical and electrical failure of DTWs; the 24hr continuous pressure condition in the network will be a challenging proposition to realize in a different situation (IWM, 2014).

DWASA prepared water supply master plan (2014), a set of guiding principles were discussed regarding water quality and availability. It was proposed to build the capacity of the organization should be enhanced for future requirements. Master plan also focused on improving coordination between stakeholders, efficient management of assets and human resources. Reduction of ground water use, protection of water supply sources to ensure pressurized water supply distribution and identification of future urban expansion areas is also suggested in Master plan. In addition to improving overall efficiency of operation and maintenance (O&M), the master plan suggested to reduce non-revenue water and power consumption. Emphasis is also given to develop strategic plan for efficient water utilization and promotion of water use conservation for demand management. Master plan also focused on collection of revenue opportunities and collection efforts need to be improved. For implementation of the master plan, capital expenditures (CAPEX) needs to be clearly identified and potential funding sources have to be indicated. The annual budget and O&M plan needs to evaluated and tariff needs to be set for DWASA accordingly. It may be necessary to establish interim objectives that ensure a gradual progression to full cost recovery over the years. The overall environmental condition of Dhaka is increasingly reaching a critical situation which is mainly due to a very dense population with high growth rates, and limited water distribution coverage for the city. On the other hand, Bangladesh is already committed to improving the water and sanitation scenario of its urban settlements. MDG was targeted by 2015. This commitment is further reinforced due to its policy of achieving Sustainable Development Goals. The SDG (https://unstats.un.org/sdgs/files/metadata- compilation/Metadata-Goal-6)has the following water related goal specified: a. By 2030, improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally b. By 2030, achieve access to adequate and equitable sanitation and hygiene for all and end open defecation, paying special attention to the needs of women and girls and those in vulnerable situations. c. By 2030, achieve universal and equitable access to safe and affordable drinking water for all. d. By 2030, substantially increase water-use efficiency across all sectors and ensure sustainable withdrawals and supply of freshwater to address water scarcity and substantially reduce the number of people suffering from water scarcity.

e. By 2030, expand international cooperation and capacity-building support to developing countries in water- and sanitation-related activities and programmes, including water harvesting, desalination, water efficiency, wastewater treatment, recycling and reuse technologies. f. By 2030, implement integrated water resources management at all levels, including through transboundary cooperation as appropriate.

The Master Plan aims to achieve these goals in the context of water supply in Dhaka city. Moreover, more reliance is given on large rivers than the peripheral rivers. The emphasis was given for collection of surface water from large rivers specially from Padma and Meghna. However, detail study was not conducted on peripheral rivers for the assessment of potential sources of surface water for Dhaka city (IWM, 2014).

2.11 Management Plan for Water Supply Project

2.11.1 Demand and Supply Side Management

The Dhaka water supply authority is considering exorbitantly expensive option of bringing raw water from distant rivers like the Meghna or the Padma, which is unlikely to be a sustainable option. Strategically therefore, abating pollution of the Balu-Sitalakhya river system including the internal conveyance canals through a combination of pollution prevention and control measures at different sources would be much more cost effective and sustainable solution. Similar approach is also to be considered for the Turag-Buriganga-Dhalswari river system (DWASA, 2014).

2.11.2 Water Reuse

The general principles and technological developments of water reuse and renovation can be discussed as follows:

a. With the technological advancement and public acceptance, greywater seems to be a potential source of water saving. Traditionally, greywater is defined as non-industrial wastewater generated from domestic processes such as dish washing, laundry and bathing. Essentially, any water, other than toilet wastes, draining from a household is greywater.

b. Greywater is a major fraction of domestic wastewater which is generally less polluted than other types of wastewater. Burnat et al. (2007) reported that the amount of greywater produced in household is 55% - 65% of the total amount of wastewater. This water generated from sinks, baths, showers, or washing machines. This water can be treated onsite or offsite for non-potable use purposes such as irrigation, toilet flushing, car washing, dust control, soil compaction, in construction works and in industrial processes

like cooling boilers and other appliances (Almeida et al. 1999). Reuse of greywater in toilet flushing and gardening can save 31-54% of potable water in households. Water reuse in long term will reduce the water demand and finally meet the requirement of water in 2035.

2.11.3 Pollution control

The tanneries are responsible for causing pollution in the Buriganga River by the contribution of toxic and persistent pollutants. Every kind of pollution making industry including tannery should be uprooted from both sides of the Buriganga River. Proper treatment plant of sewage needed before sewage disposal in the Buriganga, Shitalakhya, Turag, Balu River and Tongi Khal for that pollution making industry should have effluent treatment plant (ETP).Dissolved oxygen (DO) data measured is available only for 8 hours or less in a day which is insufficient to understand the complete diurnal variation. Continuous measurement of DO throughout the whole day or at least 12 hours will help to understand the complete diurnal variation. Proper laws should be enforced from the Department of Environment to reduce the pollution of the river water from adjacent pollution. New and old industries must be regulated under pollution control law. Pagla Sewage Treatment plant will need to be expanded to handle extra pollution load. Almost all tanneries at Hazaribagh area have been transferred to Savar area with a provision of central effluent treatment plant (CETP) to provide considerable opportunity to improve the water quality of Buriganga river.

2.11.4 Integration of Future Sources of Supply

To overcome these water related problems, water can be a designing element for structuring future development with the combination of sustainable approaches for social and physical transformation, open up opportunities for a water management system. Therefore an integrated approach such as an integrated water resource management (IWRM) system, which responds to problems that are all interrelated, is required. Alternate supply and demand management tools such as ground water recharge, rainwater harvesting, effective water pricing and reclaimed water use are suggested to meet the deficit of the current supply system through the efficient use of the scarce resources available. Institutional reform and improved water planning are required to facilitate economic growth and social development. Finally, human resource development is identified as a key factor for the sustainable effective management of this valuable resource.

2.11.5 Water Distribution System

The current distribution system is based on supplying water from the DTW of the City as discussed. Only major source of supply is the Saidabad SWTP. As result the distribution system

lacks larger pipes to transmit water from one part of the City to another. As new plants will be constructed to meet the future demand, primary distribution lines will be required to transmit the water from the sources. Each sector has a plant which will be built in phases. The primary transmission main will have to be built in each sector to transmit the water from the plants. Secondary and tertiary distribution lines will be required to distribute water to the customer end. The current network has to be changed so that the primary distribution lines are designed according to supplied water in different parts of the sector.

2.11.6 Environmental Impact Assessment (EIA) of Industries

Bangladesh Environment Conservation Act 1995 of the Section 12 and Rule 7 of the Environment Conservation Rules 1997 together form the basic framework for undertaking environmental impact assessment (EIA) for new or existing industries and projects in Bangladesh. The purpose of EIA is to enhance industries and projects by helping prevent, minimize, mitigate or compensate for any adverse environmental and social impacts. Since its establishment in 1989, the Department of Environment (DoE), which is mandated for the overall improvement in environmental governance, have not been able to adequately enforce regulations nor monitor non- compliance. The EIA review process is open to manipulation and negotiation and is of particular concern. The government must recognize that EIA is an important tool for environmental management and that environmental degradation can be minimized through effective implementation of adequately designed mitigation and monitoring plans that form major parts of EIA. It is therefore extremely important that the government, as an immediate step towards pollution abatement, institutes an independent EIA review body drawing experts from research organizations, industry associations, media and the civil society, instead of current DoE in-house review process. The outcome of the EIA review and the accepted EIA report must be displayed in a public domain e.g., at a designated website. It is also important that regular post development environmental monitoring undertaken by project proponent is subject to a third party verification and that the information is disclosed to the public.

2.11.7 Enforcement of New Law: “Clean Water Act”

Enforcement of this new law could be central to resolve water pollution problems caused by untreated municipal wastewater and industrial effluents and to mitigate the pollution caused by runoff from agricultural lands, city streets and other non-point sources. The necessities of this proposed act would ensure that the discharge of pollutants into water courses is a privilege and not a right and must be authorized by a mandated agency/ authority indicating type and concentration of pollutants, and any violation of the provision of this act will be subject to

financial penalties and imprisonment. The preceding two policy recommendations on pollution charges/ permits, and regulating ambient stream water quality can be mandated under this new act. To facilitate the provision of this Act it is further strongly recommended that independent “River/ Watershed Management Authorities” be instituted with full financial and administrative power under the overall supervision of the Prime Minister’s Office. The organizational structure and the terms of reference must be worked out in such a manner that the authorities can exercise their power and capacity in order to achieve the very objective of “Clean Water Act”. The current parliament should promulgate the proposed “Clean Water Act” in order to effectively minimize pollution in the waters of Bangladesh through appropriate instruments within the provision of this Act. Watershed or River wise independent management authorities should be instituted with full functional authorities and financial power to implement the provisions of this Act under the overall guidance of the office of the Honorable Prime Minister.

2.11.8 Land Zoning

Interestingly major industries are located in lusters in and around Dhaka city although there is no formal use of industrial land zoning except Tejgaon, Tongi and Hazaribagh which has been declared as industrial zones long ago. Land zoning has the inherent advantage of addressing industrial pollution in terms of effluent treatment and regulatory measures. Given the current urbanization process however, the government needs to review its earlier land use zoning particularly Tejgaon and Hazaribagh. These two industrial clusters are the major contributors of industrial pollution in the entire Dhaka watershed followed by Narayanganj, DEPZ and Tarabo. Pollution load from Tejgaon is considered to be the major source of Balu-Sitalakhya pollution while Hazaribagh along with domestic sewage causes serious pollution of Buriganga. The decision of relocating Hazaribagh Tanneries cluster has already been taken by the government which needs to be expedited. Government should seriously consider transformation of Tejgaon industrial area into a commercial zone as the area is now in the center of the city. The government should facilitate transformation of Tejgaon industrial area into a commercial zone considering its location within the city through offering incentives for immediate relocation of major polluting industries. The Environment Conservation Rules 1997 incorporated Environmental Quality Standards for air, water and soil, and mandated the Department of Environment to monitor air, water and soil quality on a regular basis in order to ensure environmental protection. The Department of Environment has been monitoring the air, water and soil quality at selected locations, however, not in a regular fashion. To ensure that DoE fulfils its mandate and keep the ambient quality within the recognized limits given in the Environmental Regulation of 1997, DoE needs to disclose its findings to the public regularly. This would generate indirect pressure from

the public and from the civil society on DoE to monitor the environmental quality on a regular basis. Such a disclosure policy can also educate others in the community to demand products that are cleaner than others. The government can take immediate step to incorporate in the ECR 1997 through Gazette notification, public disclosure of environmental quality information through different public media, mandatory for DoE.

2.11.9 Coordinated Efforts

Sustainable environmental improvements can only be achieved when the objectives and requirement of environmental protection are internalized in the management of industries. For this to work, a better understanding is needed of what motivates those responsible for pollution and their responses to different regulations, incentives or other pressure. Industrial associations like FBCCI, DCCI, BGMEA, Ministry of Industries, MoEF, Ministry of Water Resources, Local Authorities, together can plan pollution prevention and management programs to orient industry management towards improving environmental performance.

2.11.10 Maintaining ISO 14000 in industries

Environmental management system (EMS) is a program of continuous environmental improvement that follows a defined sequence of steps drawn from established project management practice and routinely applied for business management. The common framework for EMS is the ISO 14000 series that consists of standards covering eco labeling and life cycle assessment as well as EMS. The ISO 14000 standard requires that there be a environmental policy that includes commitment to continual improvement and pollution prevention, and a commitment to comply with relevant environmental legislation and regulation. ISO 14000 standards are voluntary but more and more industries are adopting them. MoEF should take initiatives of orienting industries to adopt ISO 14000 standards and introducing EMS.

2.11.11 Waste minimization in industrial processes

The minimization of wastes requiring disposal is becoming increasingly important as available disposal options are becoming constrained both technically and economically. Waste minimization approach often comprises avoidance that refers to actions that avoid generating wastes and utilization that make the wastes a useful input to other processes. This concept needs to be introduced in industries by demonstration projects. Pollution prevention programs are virtually based on this approach of waste minimization.

2.11.12 Environmental Monitoring Program

Systematic observation, measurement, collection and evaluation of pollutant levels in air, water, soil and food have so far remained extremely weak in absence of a strong institutional support. Routine monitoring is important in identifying the possible risks associated with the levels of pollutants. Detection of high levels of toxic pollutants exceeding baseline exposure level in any media through monitoring might emphasize the need for effective control measures. It is therefore extremely important that an environmental monitoring program be developed with the objective of monitoring priority pollutants (need to be identified) within the Dhaka watershed which could eventually be expanded to national level.

2.11.13 Clean-Up of Contaminated River Beds

It can be considered for obvious reasons that the beds of all peripheral rivers and canals within the city are heavily contaminated by pollutants from different sources. Pollution along with other types of degradation including erosion, encroachment, unauthorized and unabated commerce and business on encroached lands, and the continuing spread of unplanned urbanization is posing serious threat to the sustainability of the river systems around Dhaka city. A wide variety of pollutants including toxic heavy metals, hydrocarbons, persistent organic pollutants (POPs), municipal and industrial organics, sewage sludge, hospital wastes, pathogens are being increasingly discharged into the rivers and canals in and around Dhaka City. As a result, the grossly polluted waters and contaminated river beds have become hazardous to human health when potentially toxic substances move through the food chain or reach groundwater used for drinking water supplies. The current waste disposal practices within Dhaka watershed area have virtually made the river beds as sinks for a diverse range of pollutants. Clean up of the contaminated river beds have therefore, become a priority action while considering river pollution abatement strategies. To be effective and sustainable this river bed clean-up action, must follow some logical steps and be based on scientific analysis. The recent government initiative of excavating Buriganga river bed on an experimental basis deserves appreciation in that it reflects the positive move by the government in an effort to restore the dying rivers around Dhaka City. However, the initiative lacks a comprehensive planning that is essential for excavation of contaminated bed materials, contaminant characterization, treatment of various contaminants, identification and preparation of disposal locations for final disposal of the bed materials. The logical steps to be followed for river bed clean-up action:

a. Delineation of alignment and channel width (flood plain width) of each river

b. Identification of point sources of pollution

c. Complete stoppage of pollution discharges from all identified point sources

d. Minimizing non-point source pollution through

e. changing basin management practices

f. Sampling and scientific laboratory analysis of bed sediment volume and contaminant characteristics

g. Establishing procedure for excavation of river beds

h. Based on scientific analysis of bed sludge, separating contaminants e.g., plastics, degradable and nondegradable

i. Identification of disposal methods and sites according to contaminant characteristics

j. Appropriate treatment and disposal of different

k. fraction of contaminants

l. Setting a realistic timeframe for phased remediation of contaminated river beds

2.11.14 Rainwater Harvesting

Rainwater should be utilized for aquifer recharging. Present “Dhaka City Building Rules 2011” of RAJUK have made rainwater harvesting and groundwater recharge mandatory for all buildings having roof area more than 200 m2. This rule needs to be implemented with immediate effect.

2.11.15 Institutional Responsibilities

Under Ministry of Local Government, Rural Development and Cooperatives: provision of pure, safe, and dependable water to Dhaka citizens (including Naranyanganj); regular, safe, continuous disposal of sewage; operation and maintenance of drains for storm water disposal; collection of fees for these services. Register of government title for land (through Department of Survey and Land Records), including river beds and contiguous land; through the Deputy Commissioners, leasing of these lands, and eviction, as necessary; administration of land compensation process for private lands. Under Ministry of Local Government, Rural Development and Cooperatives: outside the DCC area, responsible for rural water supply; monitoring of water quality. Under Ministry of Shipping: responsible for survey and certification of ships and boats in the river system (including seaworthiness and waste management). Overall policy direction for industrial development; a role in development of industry in specified zones and compliance with pollution

control regulations in factory design. A priority is made in table below to take further steps for future water supply measures for pollution control and revive the peripheral rivers. Priority of evaluating of additional measures can be seen in Table 2.4:

Table 2.4: Priority of Evaluating of Additional Measures

Additional Measures Applicability Priority

Pollution Control Industries contribute to pollutans 1

River Restoration All Peripheral Rivers 2

Water Reuse Domestic Water 6

Transmission and Distribution All Supply Zones 8

Reviewing Land Zoning Land use zoning Tongi, Tejgaon and 5 Hazaribagh Environmental Monitoring Program Evaluation of pollutant levels in air, 3 water, soil and food Clean-Up of Contaminated River Beds All Peripheral Rivers 4

Responsibilities of Institutions Regarding Must have penalty for violating the 7 Dhaka Water Quality instructions of the Government

2.12 Concluding Remarks

In the above literature review, it was clearly understood that Dhaka City water supply is a serious concern for the future demand. The population is increasing gradually and ground water is also declining. Moreover, water quality of the rivers around Dhaka city is becoming more vulnerable due to pollutant loads. In recent times, no detail study is being conducted on demand and water availability for the future demand of Dhaka city to meet from peripheral rivers. Some works have been done by in 2014 by DWASA for large rivers to use as a source of surface water supply without emphasizing on all the peripheral rivers. A review regarding the guidelines for water supply management plan has also been outlined in this chapter. Keeping the requirement of future demand for projected population, environmental sustainability and cost effectiveness analyses was conducted as detailed in subsequent Chapters of this thesis on Padma and Meghna and all peripheral rivers.

CHAPTER THREE METHODOLOGY

3.1 Introduction

The study focuses on the availability of surface water of Dhaka city. It encompasses water demand and projected population, water availability by hydrodynamic model analysis, water quality analysis and cost effectiveness etc. In the sequence of the analysis, large rivers and peripheral rivers have been studied to find out the suitable options for the surface water sources of Dhaka city. Quality and quantity are the main aspects to be considered to study the water availability. The approach is to find out the availability of water by the application of flow exceedance curve and HEC RAS model. The water quality data was collected and analyzed to obtain different water quality parameter. This chapter presents the methodology of the study. It includes the approaches of the analysis, data collection for both water quality and quantity of the selected rivers under study. The selected rivers and the locations of the hydrometric stations are shown in Figure 3.1.

Tongi

Balu Turag

Buriganga Sitalakhya Meghna

Dhaleswari

Padma

Figure 3.1: Large and Peripheral River Network

3.2 Methodology

3.2.1 Population Prediction and Assessment of Water Demand

The assessment of water demand has been made based on population data collected data from the year 1975 to 2010 (BBS, 2011). Using these data, a best fit prediction formula has been developed. The projected population up to 2060 has also been estimated and compared with the census data up to 2016.

The estimation of water demand has been assessed based on estimated projected population. The following three major components of water consumption are used for calculation of total water demand: Residential consumption – split into non-low income community (non-LIC) and LIC consumption. Population growth scenarios – based on urban development plans, scope for horizontal and vertical expansion, broader growth drivers, etc. including proportion of population below poverty line (low- income community).

Non Residential consumptions – Government/institutional, commercial, industry and community consumption. Scenarios for other (commercial, industrial, institutional and community) demands as a percentage of total residential consumption - based on type of economic growth, level of service, etc.

Firefighting requirement– Firefighting requirement – calculated based on population:

Fire Demand (MLD) = 100*(Population/1000)/1000 System loss scenarios – based on likely infrastructure improvements especially at the distribution level (e.g. implementation of DMAs throughout the service area).

The main outputs are: The total water demand has been expressed in litre per capita per day (lpcd) .

Projected residential water demand (low-income and non-low-income populations) by multiplying residential consumption (lpcd) with population estimate

Similarly, projected total water demand can be estimated as follows:

Total Residential Residential Percentage of Demand = Demand + Demand x Other Demands

Required production capacity to satisfy total demand by can be obtained as follows:

Required Total = / Production Capacity Demand (100 - Percentage Losses)

3.2.2 Water Quality Analysis

Water quality analyses have been carried out for data collected from different locations of the peripheral rivers from various organizations i,e, Department of Environment (DOE), Water Resources Planning Organization(WARPO) and Dhaka Water Supply & Sewage Authority (DWASA). In addition, water samples from various locations are collected and analysed in the Military Institute of Science and Technology (MIST) laboratory. Table 3.1 and Table 3.2 show the station and data range of DOE and DWASA respectively.

Table 3.1: Water quality monitoring station of DOE Station River Year Estama Ghat Turag 2014-2016 Mirpur bridge Turag 2014-2016 Hazaribagh Buriganga 2014-2016 Kamrangir char Buriganga 2014-2016 Chadinaghat Buriganga 2014-2016 Sadarghat Buriganga 2014-2016 Farashgonj Buriganga 2014-2016 Dholai khal Buriganga 2014-2016 Bangladesh China br Buriganga 2014-2016 Pagla Buriganga 2014-2016 Demra ghat Sitalakhya 2014-2016 Narayanganj Sitalakhya 2014-2016

Table 3.2: Water quality monitoring station of DWASA (2014 -2016)

Station ID Location River Turag -2 Mirpur Turag Turag -1 u/s of Mirpur bdg Turag Buri 1 d/s of Mirpur bdg Turag Buri 2 Bashila Turag Buri 3 Islampur Buriganga Buri 4 Islampur Buriganga Buri 5 Chadinaghat Buriganga Buri 6 Pagla Buriganga Buri 7 Fatulla Buriganga Buri 8 Hariharpara Buriganga Buri 9 Nabinagar Dhaleswari Buri 10 Reckabibazar Dhaleswari Buri 11 Kagachia Dhaleswari Lakh 1 B.K. Road Sitalakhya Lakh 1a Pathantali Sitalakhya Lakh 2 Siddirganj Sitalakhya Lakh 2a Sarulia Sitalakhya Lakh 3 Demra Sitalakhya Lakh 4 Gandharbapur Sitalakhya Lakh 5 Rupganj Sitalakhya Balu 1 Keodala Balu Balu 2 balurpar Balu

Figure 3.2: Locations of Water Quality Stations

The water samples are collected from the peripheral rivers in September 2017 for the laboratory test as shown in Figure 3.3 . Again the same samples are collected from all the peripheral rivers in 2018(January) for the test can be seen in Figure 3.4. The detail of the quality parameter test has been explained in Chapter 5.

Figure 3.3: Water Samples from Rivers in September 2017

Figure 3.4: Water Samples from Rivers in January 2018

3.2.3 Ground Water Data To assess the ground water situation of Dhaka city, historical ground water table for the year 1950- 2016 has been collected from DWASA (DWASA, 2017). Historical trends of this data have been presented in Chapter 4.

3.2.4 River Data 3.2.4.1 Bathymetry

A hydrodynamic model HEC-RAS has been applied to estimate the quantity of surface water available for Dhaka city. Bathymetry data for all the peripheral rivers have been collected from BWDB. River network of Dhaka city has been set up with a network of 25 km reach of Balu river consisting of 22 cross sections, 65 km reach of Sitalakhya river having 18 cross sections, 36 km reach of Turag river with 25 cross sections, 26 km reach of Buriganga river having 13 cross sections, 16 km reach of Tongi khal having 12 cross sections, 50 km reach of Dhaleshwari with 26 cross sections and 5 junctions. The bathymetry data are summarized in Table 3.3. These data have been used for model setup.

Table 3.3: Bathymetry Data Name of the Rivers No of Cross-sections Length of River Reach Balu River 22 25 Sitalakhya 18 65 Turag 13 36 Buriganga 13 26 Tongi khal 12 16

3.2.4.2 Water Level and Discharge Data

Historical water level data is required for hydrological analysis of the study area. Bangladesh Water Development Board collects water level data regularly, these water level data have been collected for different station around Dhaka. Total 12 numbers of stations have been identified around the study area and water level from 1990 to 2016 has been collected. A list of stations is provided in Table 3.4. Among the 12 water level stations discharge was measured regularly. The discharge data from these stations has also been collected.

Table 3.4: Water Level and Discharge Stations SL Water Level Discharge Name of Place River Year Station Station 1 SW7.5 SW7.5 (Tidal) Demra Balu 1990-2016 2 SW42 SW42 (Tidal) Mill barak Buriganga 1990-2016 3 SW71 Kalagachia Dhaleswari 1990-2016 4 SW179 SW179 (Tidal) Demra SitaLakhya 1990-2016 5 SW180 Narayanganj SitaLakhya 1990-2016 6 SW299 Tongi Tongi Khal 1990-2016 7 SW302 SW302 (Tidal) Mirpur Turag 1990-2016

3.2.5 Analysis of Water Availability

As stated earlier (Art. 2.5), two methods have been applied to analyse the availability of water. These are analysis by flow duration curve and application of mathematical model. The description of flow duration curve has been given in Chapter 2 Art. 2.5. However, in the following sections, a brief methodology of mathematical model application has been described.

3.2.5.1 Application of Mathematical Model

A hydrodynamic model, HEC-RAS has been developed consists of all the peripheral rivers namely the Balu, Sitalakhya, Turag, Tongi khal, Buriganga and Dhaleshwari rivers. Bathymetry data is used to prepare a river networks consisting of the connectivity of the river system, cross-section data and the junction information. Initial and boundary conditions of the river network have been provided for the year 2014. Model simulations have been carried out for unsteady flow conditions. Preprocessing and input of all the necessary data have been made prior to model run. At all upstream and downstream boundaries, the times-series required are provided by BWDB river levels, there are four upstream inflow locations and one downstream water level point defined for the model. Model Domain for the river network can be seen satellite image as shown in Figure 3.5. Model has been calibrated for the year 2014 and validated for the year 2015.

Figure 3.5: Model Domain and Hydrometric Stations

3.2.5. 2 Model Calibration and Validation

For present study, the Manning n for channel is determined during calibration and validation of model with existing geometry. The value of Manning’s n is variable and depends on a number of factors such as surface roughness, vegetation, channel irregularities, channel alignment scour and deposition obstructions and stage discharge etc. Usually for the alluvial rivers, the value of Manning’s n varies from 0.025 to 0.040. Details of the model calibration and validation are given Art.6.9.3.

3.2.5.3 Analysis for Surface Water Withdrawal

As stated in Art 3.2.2, water demand has been calculated as per population of the Dhaka city. In previous sections Art. 3.2, methodology for analysis of water quality and quantity has been discussed. However, the water quality and quantity may differ in different season. It is obvious that water withdrawal is related to the demand for the population and many other uses. The effect of water withdrawal has also been simulated in the model. Moreover, the environmental flow and navigation requirement have also been addressed in the calculation. A Tennant method has been used for environmental flow requirement. Navigability criteria prescribed by BIWTA has been

adopted for inland water ways requirement. Finally, it was recommended the actual quantity of water which may be available for the supply of Dhaka city.

3.2.6 Evaluation of Sources

The surface sources are the large rivers and peripheral rivers have been assessed in terms of quality, quantity and cost effectiveness. Based on these assessments, an attempt has been made to evaluate the available sources in terms of their relative merits. Th is evaluation has been done to identify the most appropriate surface water source for Dhaka city water supply. Figure 3.6 shows the various scoring system for this evaluation.

Water Availability Index

Surface Water Water Quality Index Availability for Future Demand of Dhaka City Cost Effectiveness Index

Overall Quantification of Availability

Figure 3.6: Flow Diagram of Evaluating the Sources

3.3 Flow Diagram Showing Overall Methodology of the Study

As per approach and methodology, population prediction calculation and future demand was forecasted by statistical method. Dhaka has a total population of over 16 million, and the city has shown population growth of about 4.2% annually. The vibrant culture and thousands of Bangladeshi businesses and international corporations has contributed to migration and population growth. However, like many other metropolises in the world, the growing population has led to an increase in pollution, congestion and poverty, amongst other problems. Ground water sources were evaluated as it declining every year and surface water sources was analysed to reduce the dependency on ground water sources. Then water quality test and analysis of different parameter were carried out to 53

see the feasibility of its use. Then the cost effectiveness was carried out for sources of surface water i,e large and peripheral rivers. To see the surface water sources at first, flow and water level hydrograph was constructed. After determination of environmental flow and flow exceedance curve amount of water required for abstraction was found and validated through HEC RAS model. The flow duration curve presented as a graph of flow rate (discharge) versus percent of time that flows are greater than, or equal to, that flow. Exceedance probability represents the odds that a designated value is going to be exceeded. For example, if the data regarding the average cost of bread over a 10- year span, exceedance probability calculations would allow to determine the odds that bread will cost more than this average when actually go to the store. Finally implementation plan is suggested and concluded with few recommendations. Figure 3.7 consists of salient features and components of the study.

Water Sources

GW Sources SW Sources

Delineation of future Dhaka city area Hydrology, WL, Q Analysis

Water Quality Analysis Future Population

E-flow requirement Future Demand

Navigability requirement

Analysis of Possible Withdrawal

Effect of Withdrawal Using Model

Suggested Withdrawal

Cost Analysis

Recommended Water Sources

Figure 3.7: Flow diagram showing the Methodology of this study

3. 4 Concluding Remarks

Methodology of this research has been described in this chapter. A brief summary of the activities carried out in this study can be summarized in Table 3.5.

Table 3.5 : Summary of the activities

River Demand Water Availability Quality Analysis Cost Analysed Prediction Analysis Effectiveness Padma Population Water availability was Analysis carried Cost Meghna projection and carried out by out by various tests effectiveness Turag water demand discharge and WL of quality analyzed by Tongi Khal calculated by hydrograph, parameter of all comparative Buriganga statistical exceedance curve, rivers data analysis Dhaleswari method environmental flow respectively Shitalakya requirement, navigability and was Balu validated by HEC-RAS model

Details analyses have been carried out for the quality and quantity of the surface water sources. These are separately described in subsequent Chapters of this thesis (Chapter 4 to Chapter 7).

CHAPTER FOUR

ASSESSMENT OF EXISTING AND FUTURE WATER DEMAND

4.1 Introduction Forecasting of water demand is a crucial component in the successful operation of water supply system. Accurately forecasted water demand either in short-term, or medium-term, or long-term time horizons can be very useful for capacity planning, preparation of maintenance, cost effectiveness and optimization of the operations of a water system. In addition, adequately forecasted demand will be a basis for the strategically decision making on future water sources selection, improvement of the available water sources. Future water demand will also help in designing of the abstraction options so that water resources are not exhausted. All users have the right to access to available resources in near future. This chapter describes the existing progression of population and prediction of future water demand for Dhaka city. The estimation of future water demand addressing the uncertainties associated to the existing supply scenario and growth of population has been illustrated in the following sections.

4.2 Present Situation of Groundwater DTWs Over the years the number of DTWs has been increased enormously. A graph showing the increasing number of DTWs is shown in Figure 4.4. At present 78% of the total supplied water is provided from 750 wells which were more than 88% before the introduction of Saidabad Phase II SWTP. Every year more numbers of new DTWs are installed to meet the increased demand of the city. Over the years, the increasing trend of DTW in Dhaka city is shown in Figure 4.1:

Figure 4.1: Increasing trend of DTWs over the years 57

The gradual mining depth of DTWs for water extraction is shown at Figure 4.2. It was shown that mining depth for DTW is an increasing trend. For instance, in 1960 the depth was 60 m and in 2017 the depth reaches to 375 m. Some DTWs are used to extract water from a depth of 375 meters which is an alaming situation.

1960 1970 1980 1990 2000 2002 2004 2006 2008 2010 2014 2017 0

100 80 85 100

150

200 160 175 190 200 DTWs (meter)

300 250

Depth of 310

400 375 Year

Figure 4.2: Gradual increase in mining depth of DTWS

Though it was found that, pumps operated more than 20 hours a day, most of the pumps are operating more than the recommended time. As a result, the aquifer is not getting minimum required time for recharging. Again, the rate of groundwater depletion varies in different areas of the city. The rate of groundwater depletion in different areas of the city is shown at Table 4.1, Figure 4.3 and Figure 4.4.

Table 4.1: Groundwater depletion state in Lalbag, Motijheel, Cantonment, Mirpur, Tejgoan and Dhanmondi

Groundwater depletion state in m Year Mirpur Lalbagh Motijheel Tejgaon Gulshan Cantonment Dhanmondi 2000 29.9 27.0 38.8 25.1 33.5 20.8 16.8 2001 32.5 29.2 42.7 28.0 37.3 23.6 19.6 2002 35.4 32.3 45.5 30.7 40.2 27.0 21.0 2003 38.1 35.5 48.0 33.4 42.3 30.1 23.3 2004 41.2 39.0 50.6 35.9 43.3 32.9 25.9 2005 44.2 42.7 53.4 38.5 45.2 36.1 28.6 2006 47.3 46.3 56.5 41.4 57.2 39.0 31.2 2007 50.5 50.0 59.7 44.4 49.3 41.6 34.0 2008 53.75 53.7 62.6 47.2 52.1 44.5 37.1 2009 57.1 57.0 65.7 50.6 54.7 47.5 40.5 2010 60.5 60.3 68.8 53.8 57.2 50.8 43.4 2011 64.0 63.8 72.0 57.1 60.3 54.2 47.8 2012 67.4 67.0 75.0 60.3 63.0 57.5 51.2 2013 70.9 70.9 79.0 63.6 65.8 60.9 54.9 2017 74.3 73.5 83.0 66.8 68.6 64.2 58.5 58

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 0

10 20 30 40 50 60 70 80 Groundwater Table (meter)Table Groundwater 90 Lalbagh Motijheel Cantonment

Figure 4.3: Groundwater depletion state in Lalbagh, Motijheel and Cantonment 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 0

60 Groundwater Table (meter)Table Groundwater 70

Tejgaon Gulshan Dhanmondi

Figure 4.4: Groundwater depletion state in Tejgaon, Gulshan and Dhanmondi

Groundwater depletion is one of the prime causes of fresh water crisis which is directly related to over extraction triggered by increased demand of the city. Premature well failure is another challenge of DWASA which also affects the overall water production capacity. The expected life time of a pump is considered to be 30 to 40 years but every year 40 to 60 DTWs are being replaced just after an average life span of 2 to 3 years. Clogging due to over extraction and small particles from aquifer, poor design and improper construction supervision are a few major causes of these premature well failures. SWTPs cannot produce at their optimum capacity due to non-availability

of surface water. Surface water pollution is another cause of fresh water crisis of the city. Due to industrial waste, solid waste and sewage disposal the surface water of Dhaka City is getting exceedingly polluted. The pollution level has gone so high that in many cases the water is unusable in the SWTPs.

4.3 Surface Water Treatment Plants (SWTP) Operated by DWASA

In order to collect the information regarding the treatment capacity, production, quality parameter and cost effectiveness on the water supply situation numbers of visits have been conducted to existing SWTPs (Saidabad, Chadnighat, Godnail, Sonakanda) from 15 November to 25 November 2017. The officials informed that SWTPs cannot produce at their optimum capacity due to unavailability of raw surface water. Production capacity reduces more during dry season due to less flow of water. For example, Chandnighat SWTP has a capacity of treating 39 MLD but produces only 3 MLD on an average during dry seasons due to low water level in Buriganga River. The use of chemicals for the treatment of raw surface water in these SWTPs is increasing significantly. It was also reported that if the intake water quality deteriorates more, it will not be possible to treat any more. As a result, due to increased demand and deteriorating water quality of peripheral rivers, supplying water from Padma and Meghna River is an utmost need. At present DWASA has 4 SWTPs with total production capacity are given at Table 4.2.

Table 4.2: Details of SWTPs

Serial Name of SWTPs Capacity (MLD) Coverage Area 1. Saidabad Water Treatment 450 Mods Zone 1, 2, 3, Plant (Phase 1 and 2) 4, 5, 6, 7 2. Chadnighat (Dhaka) Water 39 Mods Zone 2, 3 Works 3. Narayanganj (Godnail) Water 33.17 Narayanganj west Works 4. Sonakanda Water Works 1 Narayanganj east

600

550

500

450 Monthly Production Monthly

400 Jul-13 Oct-13 Apr-14 Jan-14 Feb-14 Mar-14 Nov-13 Dec-13 Aug-13 Sep-13

Capacity Production

Figure 4.5: Seasonal variations in monthly production of SWTPs

4.4 Water Supply as Surface Water from River Sources In a personal communication of DWASA, was revelaed that the actual fresh water production of DWASA is around 2196 MLD whereas the demand is more than 2300 MLD. It was revealed that the maximum production capacity of DWASA is 2486.47 MLD, but it can utilize 88.34% of maximum level due to various reasons discussed earlier. As a result, there is continuous shortage of 100 MLD or even more fresh water in wet season. This shortage becomes more during dry season stated in article.Around 80.56% of the supplied water of Dhaka comes from DTWs and rest 19.44% is obtained by treating surface water. Due to lowering of groundwater table neither it is possible to increase the rate of production nor is it feasible to dig more numbers of wells. All these conditions necessitate the requirements of exploring alternative options of water supply for meeting the present and future demand of the city.

4.5 Population Projection The population data has been collected from Bagladesh Buraeu of Statistics (BBS-2011) for the years 1975 to 2010 . Best fit curve has been obtained and to be extrapolated for future prediction.These data has been plotted as shown in Figure 4.6.

Population Trend(1975-2010) 20

5 Population in Million 0 0 10 20 30 40 50 5 years census interval from 1975

Figure 4.6: Population trend of Dhaka from 1975 to 2010

Based on the data and trend of graph the following equation was obtained

y=0.0035x2+0.2011x+0.9768 (1)

Here in equation (1) y is the population in million and x is the census interval in 5 years.

In order to estimation and projection of future population a graph has been generated and obtained the population upto 2060 as shown in Table 4.3.

Table 4.3: Projected population upto 2060 Year Projected Population in Million 2020 19.78 2025 22.62 2030 25.64 2035 28.84 2040 32.20 2045 35.75 2050 39.46 2055 43.36 2060 47.43

4.6 Future Water Demand Assessment

Future water demand has been calculated as per the population projection shown in Table 4.3. Water demand is divided into three main categories i, e, residential demand, non-residential demand and fire fighting requirement. System losses in water demand are also considered as percentage of these main categories. 62

4.6.1 Residential Water Demand

The present area of Dhaka city is 404 sq km. In 2035 the area will be 617 sqkm and in coming future it will be even more. The breakdown of indoor household water consumption was estimated from the survey conducted in the year 2012, 2014 and 2016 for sample size 50, 45 and 60 numbers of families respectively.The amount of water consumed per person for personal washing (showering, ablution and face/hand washing), clothes washing and floor washing seems to be logical in many cases as found from collected data. The residential consumption rate is considered 150 lpcd; non- residential (other) consumption is around 12%, fire fighting 5 lpcd and system loss is assumed as 8%. Breakdown of all possible water consumption as resulted from survey is shown in Table 4.4.

Table 4.4: Breakdown of indoor household water consumption

Feature Collected Data Collected Data Collected Data in 2012 in 2014 in 2016 lpcd % lpcd % lpcd % Personal Washing 75 36% 70 45% 72 25% Toilet Requirement 25 17% 30 20% 28 19% Washing Apparatuses 26 16% 25 17% 24 13% Clothes Washing 25 21% 17 13% 20 12% Drinking 2 1% 2 2% 2 1% Cooking 3 3 2% 4 18% Floor washing 3 9% 2 1% 3 12% Other Uses 1 1 0% 1 0% Total 160 100% 150 100% 155 100% Sample size 50 45 60

4.6.2 Non Residential Water Demand Non-residential water consumptions such as consumptions in government/institutional, commercial, industrial and community buildings have been considered as a percentage 12% to 20% of total residential consumption.

4.6.3 Total Future Water Demand

Future demand assessment incorporates the key water demand factors such as population projection, per capita daily consumption and other residential and non-residential demands. The water requirement has been used to assess future demand for different scenarios up to 2035.The required production capacity was estimated for each of the scenarios based on different rates of system losses. The population has been projected based on previous inter-census growth rates and future urban development plans. Per capita daily consumption rates are based on the household

survey findings for different structure types, possible reductions in poverty levels in the future, expected responses to tariff re-structuring and projections of changes in housing structure types.The proportion of non-residential (other) water demands has been based on urban development plans and possible composition of economic activities in Dhaka. The different rates of system losses have been based on expected implementation of existing and new Dhaka service areas and assumptions on improved operation and maintenance of water supply infrastructures. It is expected that the projected water demands can be updated as part of regular census in expanded urban development plans. The extent of service area of Dhaka expanded to part of Tongi and Gachcha in the North West, Kaliganj in the north east, Rupganj in the west, Keranigonj in the south west and Bandar in the south east. Population density and existing and expanded Dhaka city is shown in Figure 4.7.

Figure 4.7: Map showing population density of Dhaka city

Notes: a. Initial residential consumption rate based on household demand survey b. Area expansion in 2020 includes Purbachal, Tongi, Gachcha and part of Keraniganj and Rupganj c. Area expansion in 2030 includes parts of Rupganj, Sonargoan and additional parts of Keraniganj.

A calculation was carried out to determine the future water demand of the city. In 2017 the estimated population is 18 million, residential consumption rate is 150 lpcd and considering other consumption, fire fighting, loss the total demand stands 2727 MLD. At present, 8% loss considered in the system where it is expected to improve further with the development of technology and infrastructure. Therefore, the gradual decrease of system loss upto 2% has been considered in this study. Likewise calculation upto 2035 year have been estimated and found around 5105 MLD can be seen in Table 4.5. The coverage area will increase with the time.The coverage area will be increased to 617 km2 by 2025 km2 and will be increased after the year 2045 to area upto700 km2 with more population and expansion of area (DWASA, 2016). A calculation has been made for the same scenario upto the year of 2060 and demand w as estimated around 7091 MLD has been shown in Table 4.6.

Table 4.5: Estimation of projected water demand from 2017 upto 2035 Year 2017 2020 2025 2030 2035 Item Coverage Area (Sq km) 404 497 617 617 617 Estimated Population Served (Million) 18 19.78 22.62 25.64 28.84 Resedential Consumption Rate (Lpcd) 150 150 150 150 150 Residential Consumption (MLD) 2250 2654.4 3059.1 3460.6 4009.2 Percentage of other Consumption (%) 12% 14% 16% 18% 20% Other Consumption (MLD) 270 371.616 489.456 622.908 841.932 Total Consumption (MLD) 2520 3026.016 3548.556 4083.508 4851.13 Fire Fighting Requirment (MLD) 5 7 8 9 11 Total Demand (MLD) 2525 3033.016 3556.556 4092.508 4862.13 Percentage of Loss% 8% 7% 6% 5% 5% Total Loss (MLD) 202.00 212.31 213.39 204.63 243.11 Required Production Capacity (MLD) 2727.00 3245.33 3769.95 4297.13 5105.24

Table 4.6: Estimation of projected water demand from 2040 upto 2060

Year 2040 2045 2050 2055 2060 Item Coverage Area (Sq km) 617 700 700 700 700 Estimated Population Served (Million) 32.20 35.75 39.46 43.36 47.43 Resedential Consumption Rate (Lpcd) 150 150 150 150 150 Residential Consumption (MLD) 4291.25 4570.8 5048.4 5327.95 5594.6 Percentage of other Consumption 22% 21% 22% 23% 24% Other Consumption 944.075 959.868 1110.65 1225.43 1342.7 65

Total Consumption 5235.325 5530.67 6159.05 6553.378 6937.3 Fire Fighting Requirment 12 12 12 14 15 Total Demand 5247.325 5542.67 6171.05 6567.38 6952.3 Percentage of Loss 4% 3% 3% 2% 2% Total Loss 209.89 166.28 185.13 131.35 139.05 Required Production Capacity 5457.22 5708.95 6356.18 6698.73 7091.3

Final outcome of Table 4.6 is the total production capacity required for the Dhaka city which is 2727 MLD in 2017 and 5105 MLD in 2035. In the same process the demand will increase around 7091 MLD in 2060 which is very high compared to present population.

4.7 Concluding Remarks

In this chapter, prediction of future population and demand has been assessed to meet the future water requirement. The causes of water crisis of the city are the rapid groundwater depletion, extreme surface water pollution and untreated surface water sources. It is apparent that present amount of water supply and its infrastuctural arrangement are not sufficient to meet the future water requirement of the Dhaka city. There is a necessity to explore surface water sources to solve the water crisis. The Dhaka area is expected to expand from the current 404 km2 to about 617 km2 by 2035. During this period, the total population in the 617 sqkm area is expected to increase from 16 million in 2011 to 29 million by 2035. The total demand is expected to increase from about 1500 MLD in 2011 to 5105 MLD in 2035. Beyond 2035, there is likely to be around 50% increase in total demand by the year 2060. Water consumption in Dhaka city is showing a rising trend as the population and urban development are being expanded. This consequence needs due attention with proper estimation and evaluation of the surface water sources.

CHAPTER FIVE ASSESSMENT OF WATER QUALITY

5.1 General

Water quality is a very important criterion for selection of raw water source for a surface water treatment plant. Knowing the water quality enables us to determine whether or not the water is fit for its intended use. It also provides an estimate of the degree of fitness and required level of treatment at the water treatment plant. The water for which concentrations of pollutants do not exceed their respective standard values is considered acceptable or safe. Strict enforcement and proper observation of these standards could largely ensure human safety and protect environmental quality from further deterioration. These standards primarily depend on the intended use of water. Bangladesh has set comprehensive water quality standards for drinking water (GoB, 1997); but for inland surface water quality, standards have been set only with respect to four parameters (pH, DO, BOD5, and Total Coliform (TC). This chapter presents the analysis of the quality of Padma and Meghna and all peripheral rivers around Dhaka city.

5.2 Water Quality Parameters

Surface water are said to be polluted when there are excessive concentrations of particular substances for sufficient periods of time to cause identifiable adverse effects. They are defined in terms of physical, chemical and biological characterization of water. The concentrations of these substances vary depending on season, the natural setting of the watershed, land use pattern and to a large extent on human activities. For example discharge of wastewater greatly adds to the organic loading of the surface water while clearing of land can result in increased erosion and sediment load in surface waters. In general, water quality deteriorates during the dry season, when there is no or little precipitation. A general classification of water quality variables that are commonly used in water quality monitoring system are as follows.

1. General, physical and chemical Temperature, Dissolved Oxygen (DO), pH, Conductivity, Alkalinity, Suspended Solids 2. Nutrients 3- NH4-N, NO2-N, NO3-N, PO4 3. Inorganic Major ions: Na, K, Ca, Mg, Chloride, Sulphate 67

Metals: Fe, Mn, Al, Hg, Cd, Pb, Zn, Cu, Ni, Cr 4. Organic BOD, TOC, COD, Pesticides, Phenols, Organic Solvents, Oil & Hydrocarbons 5. Biological Chlorophyll-A, Phyto- and Zooplankton, Macrophytes, Macrobenthos, Fish 6. Microbiological Total and faecal coliforms, Streptococci, Salmonella The major inland rivers of Bangladesh adjacent to Dhaka city and its peripheral rivers have been critically evaluated in the subsequent paragraphs with the help of available analytical data from both primary and some secondary sources as previously as articulated in Art. 3.2.2 of Chapter 3.

5.3 Water Quality of Padma and Meghna Rivers

The Padma is major trans-boundary river of Bangladesh which is the main distributary of the Ganges, flowing generally southeast for 120 kilometres to its confluence with the Meghna River near the Bay of Bengal. Its maximum depth is 479 m and average depth is 295 m having an average discharge rate of 35,000 m3/s, which increases to 750,000 m3/s during wet season and eventually decreases to 15,000 m 3/s during dry season(Allison, 1998). This river can be a suitable raw water source for water supply in Dhaka city. There are two possible options for surface water abstraction from the river Padma. One is beside Jashaldia village under Louhajang thana and the other option is beside Kobutorkhola village under Sreenagar thana of Munshiganj. The intake structure may be built on the left bank and the raw water transmission line will travel along Dhaka-Mawa highway towards the city. It should be noted however that Dhaka WASA has already decided to construct a surface water treatment plant at Jashaldia with a capacity of 450 MLD (Phase-I) and construction of the plant is currently underway.

The Meghna River is another major river flowing adjacent to the capital city. The river's average depth is 308 m and maximum depth is 490 m. It has a a length of 296 km, and it is the widest river of Bangladesh (Chowdhury, 2012). This river also can provide ample water for water supply in Dhaka city. It should be noted that a water treatment plant is being constructed at Khilkhet/Gandharbpur, which will add 1,000 MLD water to the DWASA supply system by the year 2030 (500 MLD capacity plant under Phase I by 2020 and another 500 MLD capacity plant by 2030) by drawing the raw water from the Meghna river at Bishnondi. The Saidabad phase III plant (with a capacity of 450 MLD), is also considering withdrawal of water from Meghna river at Haria which is several kilometres downstream from Bishnondi. To monitor water quality,

water samples were collected from two locations - Meghna Ghat and Bishnandi of Araihazar Upazilla, Narayanganj for the Meghna River by WARPO during the monsoon and dry season. At the same time, water samples for the Padma River were collected from two locations named Jashaldia and Kobutorkhola. These points were selected on the basis of their suitability as intake locations. The sampling locations are summarized in Table 5.1. Figure 5.1 and Figure 5.2 show the sampling locations of Padma and Meghna River, respectively.

Table 5.1: Locations for the analysis of water quality parameters of Padma River

River Name Latitude Longitude Location Padma 25.46954 90.29388 Jashaldia Padma 23.52244 90.18264 Kobutorkhola Meghna 23.7646 90.72303 Bishnondi Meghna 23.63823 90.62072 Meghna Ghat

Figure 5.1: Sampling Locations of Padma River on Google Earth

Figure 5.2: Sampling Locations of Meghna River on Google Earth pH pH level of Padma River varied from 7.1 to 8.1 (Figure 5.3) while standard for inland surface water is 6.5 to 8.5 . Maximum pH was found at Jashaldia Bank in May and minimum level was at Kobutorkhola in March. It has been also observed that pH level of the river throughout the years was within the standard limit for surface water bodies.

pH of Padma River 9

7 pH Jasaldia Kobutorkhola 6

5 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Months

Figure 5.3: pH along Padma River for the year 2016 The pH level of the Meghna River for the year 2016 is shown in Figure. 5.4. It shows that pH varies over a narrow range from 6.9 to 7.7 during the year, satisfying the Bangladesh standard for inland surface water bodies.

pH of Meghna River 9

7 pH Meghna ghat Bishnandi 6

5 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

Figure 5.4: pH along Meghna River for the year 2016

Electrical Conductivity (EC)

Electrical Conductivity, in particular specific conductance, is one of the most useful and commonly measured water quality parameters. In addition to being the basis of most salinity and total dissolved solids calculations, conductivity is an early indicator of change in a water system. The electrical conductivity of the water depends on the water temperature: the higher the temperature, the higher the electrical conductivity would be. The electrical conductivity of water increases by 2-3% for an increase of 1 degree Celsius of water temperature. Many EC meters nowadays automatically standardize the readings to 25 degree Celsius. Most bodies of water maintain a fairly constant conductivity that can be used as a baseline of comparison to future measurements. Significant change, whether it is due to natural flooding, evaporation or man- made pollution can be very detrimental to water quality. Figure 5.5 shows the comparative state of yearly average EC of Padma and Meghna Rivers from 1995 to 2016 at Jashaldia and Bishnandi locations respectively. In both the scenario, both the river shows a gradual rise in amount of EC. However, Figure 5.5 and Figure 5.6 show the condition of EC throughout the year 2016 in the sample locations.

600 EC

500

400

300 Padma

EC(µS/cm) 200 Meghna

100

0 1995 2000 2005 2010 2016 Year

Figure 5.5: EC along Padma and Meghna Rivers at Jashaldia and Bishnandi

EC 600

500

400 Jashaldia 300 Kobutorkhola

EC(µS/cm) 200 Bishnandi Meghna ghat 100

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

Figure 5.6: Monthly EC along Padma and Meghna Rivers at sampling points

Chloride

Chloride is one of the major anions to be found in water and sewage. Its presence in large amounts may be due to natural processes such as the passage of water through natural salt formations in the earth or it may be an indication of pollution from sea water intrusion, industrial or domestic waste or deicing operations. Potable water should not exceed 250 mg/L of chloride. Figure 5.7 shows gradual change of Chloride concentrations in Padma and Meghna Rivers from 1995 to 2016 at Jashaldia and Bishnandi locations respectively; whereas Figure 5.8 shows its depilated state throughout the year 2016 for both the rivers. Maximum concentration of chloride is found at Bishnandi (194 mg/l in 2016) in March and minimum concentration (115mg/l in 2016) in October at Jashaldia.

200 Chloride

150

100 Padma Meghna

Chloride(mg/l) 50

0 1995 2000 2005 2010 2016 Year

Figure 5.7: Chloride concentration along Major Rivers at Jashaldia and Bishnandi

Chloride

250 200 150 100 50 Chloride(mg/l) 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

Jashaldia Kobutorkhola Bishnandi Meghna ghat

Figure 5.8: Chloride concentration along Major Rivers in 2016

Turbidity

Turbidity is a measure of the degree to which the water loses its transparency due to the presence of suspended particulates. The more total suspended solids in the water, the murkier it seems and the higher the turbidity. Yearly average turbidity level of Padma River was very low and varied from 5 to 5.5 NTU; whereas, in Meghna it is from around 6 NTU (Figure 5.9). Highest and lowest value was found in June-July in sampling points of Meghna River and December-January in sampling points of Padma River respectively.

7 Turbidity 6

5 4 3 Padma

Turbidity(NTU) 2 Meghna 1 0 1990 1995 2000 2005 2010 2015 2020 Year

Figure 5.9: Average Yearly Turbidity along Major Rivers

Dissolved Oxygen (DO) and BOD

Dissolved oxygen gets into the water by diffusion from the atmosphere, aeration of the water as it tumbles over falls and rapids, and as a waste product of photosynthesis. Reduced DO levels in river water may be because the water is too warm. Figure 5.10 shows variation of DO in the Padma and Meghna Rivers at Jashaldia and Bishnandi respectively. DO vary from 4.6 to 7.4 mg/l at Padma in the late 90s. DO level was lower at Bishnandi in February to May than the corresponding Bangladesh Standard. BOD level was under the standard limit (≤6 mg/l) all over the year except in November at Jashaldia and Kobutorkhola.

8 BOD 7

6 5 4 Padma 3 BOD(mg/l) Meghna 2 1 0 1995 2000 2005 2010 2016 Year

Figure 5.10: Yearly BOD along Padma and Meghna Rivers

Characteristics of Padma River Water

Tables 5.2(a) and 5.2(b) show summary characteristics of surface water samples collected and analyzed as a part of the environmental study of the water treatment plant at Jashaldia (BRTC, BUET, 2010). The suspended solids concentration of the water samples varied over a wide 74

range. Chloride concentration of most surface water samples were found to be low, especially of those collected from Padma River in November 2009. Most of the samples had relatively low iron concentration. As expected, the As concentrations of the surface water samples have been found to be very low. Table 5.2(a): Summary characteristics of surface water samples collected in July 2009 (Source: BRTC, BUET, 2010)

Sl. No. Water Quality Parameter Unit Concentration Inland surface water Range Present in quality standard Water Samples 1 pH -- 6.89 – 7.76 6.5-8.5 2 TDS mg/l 93 – 178 -- 3 TSS mg/l 6 – 966 -- 4 Electrical Conductivity (EC) mg/l 131 – 306 -- 5 Chloride (Cl-) mg/l 2 – 20 -- 6 Ammonia (NH3-N) mg/l 0.253 – 0.580 -- 7 Iron (Fe) mg/l 0.02 – 0.52 -- 8 Arsenic (As) mg/l < 0.001 – 0.009 -- 9 Dissolved Oxygen (DO) mg/l 2.74 – 4.95 ≥ 5b, d, e, f, ≥ 6a, c 10 BOD5 mg/l 0.4 – 4.8 ≤ 2a, ≤ 3b, ≤ 6c, d, ≤ 10e, f 11 COD mg/l 5 – 38.8 -- 12 Total Coliform (TC) mg/l 650 – TNTC ≤ 50a, ≤ 200b, ≤ 1000f, ≤ 5000c, e 13 Fecal Coliform (FC) mg/l 20 – 4980 -- 14 Oil and grease mg/l < MDL -- Table 5.2(b): Summary characteristics of surface water samples collected in November 2009

Sl. No. Water Quality Parameter Unit Concentration Inland surface water Range Present in quality standard Water Samples 1 pH -- 7.93 – 8.42 6.5-8.5 2 TDS mg/l 112 – 150 -- 3 TSS mg/l 5 – 179 -- 4 Electrical Conductivity µS/cm 183 – 230 -- (EC) 5 Chloride (Cl-) mg/l 2 – 6 -- 6 Ammonia (NH3-N) mg/l 0.145 – 0.268 -- 7 Iron (Fe) mg/l 0.22 – 1.4 -- 8 Arsenic (As) mg/l 0.001 – 0.004 -- 9 Dissolved Oxygen (DO) mg/l 4.34 – 4.7 ≥ 5b, d, e, f, ≥ 6a, c 10 BOD5 mg/l < 0.2 – 4.8 ≤ 2a, ≤ 3b, ≤ 6c, d, ≤ 10e, f 11 COD mg/l < 2 – 13 -- 12 Total Coliform (TC) mg/l 80 – TNTC ≤ 50a, ≤ 200b, ≤ 1000f, ≤ 5000c, e 13 Fecal Coliform (FC) mg/l 50 – TNTC -- 14 Oil and grease mg/l < 0.1 – 21.5 -- 75

Note: a: to be usable as a source of water supply only after disinfection; b: to be usable for recreational activity. c: to be usable as a source of water supply after conventional treatment; d: to be usable for fisheries. e: to be usable for various process and cooling industries; f: to be usable for irrigation. Dissolved oxygen (DO) concentration of the water samples collected in July varied from 2.74 to 4.95 mg/l, while it varied over a narrow range of 4.34 to 4.70mg/l for the Padma River water samples collected in November 2009. The BOD and COD concentrations of the surface water samples were not very high. As expected, the surface water samples have been found to contain high concentrations of both TC and FC, common for most surface waters in Bangladesh. Some of the samples collected from the Padma River in November 2009 were found to contain relatively high concentrations of oil and grease.

Characteristics of Meghna River Water

Water quality of Meghna river was assessed as a part of feasibility study of Saidabad Phase III project (BRTC, BUET, 2013). Three batches of water samples were collected from the Meghna River at the Baidder Bazar Intake, Haria, Sonargaon, Narayanganj on 13th July, 24th August and 28th September, 2013. The water quality characteristics of these samples provide the baseline water quality at the intake point of the proposed WTP. Sampling location was about 100 - 150 ft from the river bank water line. Sampling was done from about one meter below the water surface to avoid the presence of floating impurities. During each sampling, in-situ measurements were done for the dissolved oxygen, pH, temperature and turbidity of the water sample. Detailed laboratory analysis has been conducted on the three collected water samples to determine the water quality. The results of the in-situ and laboratory analysis of the three samples are presented in Table 5.3 along with Bangladesh Drinking Water Standard and inland water quality standard (ECR, 1997).

Table 5.3: Water Quality Test Results from Meghna River at Meghna Ghat, Narayanganj

Concentration present Second Third Bangladesh Inland First Sample Sample Sl Sample Drinking Water Water Quality (collected (collected No. Unit (collected Water Quality Parameter 13th July, 24th 28th Sept., Standard Standard, 2013) August, 2013) (ECR,1997) ECR,1997 2013) 1 pH - 7.03 7.26 6.92 6.5-8.5 6.5-8.5 Color 2 Pt-Co 62.0 159.0 85.0 15 -- (Apparent) 3 Color (True) Pt-Co 13.0 19.0 15.0 15 -- 4 Turbidity NTU 6.87 17.1 13.0 10 -- Total mg/L as 5 16.0 20.0 36.0 200-500 -- Hardness CaCO3 6 Chloride (Cl-) mg/L 10.0 7.0 7.0 150-600 -- Total 7 Dissolved mg/L 35.0 20.0 27.0 1000 -- Solids (TDS) 8 Iron (Fe) mg/L 0.38 0.44 0.32 0.3-1.0 -- ≤ 50a, Total CFU/10 ≤ 200b, 9 Coliform 390 20 134 0 0 mL ≤ 1000f, (TC) ≤ 5000c, e Fecal CFU/10 10 210 20 110 0 -- Coliform (FC) 0 mL Electrical 11 Conductivity µS/cm 58 53 68 -- -- (EC) at 25oC Dissolved ≥ 5b, d, e, f, 12 mg/L 7.60 6.0 5.25 6 Oxygen (DO) ≥ 6a, c mg/L as 13 Alkalinity 21.0 25.0 30.0 -- -- CaCO3 Nitrate (NO3- 14 mg/L 0.4 0.2 0.4 10 -- N) Ammonium 15 mg/L 0.23 0.354 0.274 0.5 -- (NH4-N) Ammonia 16 mg/L 0.001 0.004 0.001 -- -- (NH3-N) Phosphate 17 mg/L 0.067 0.081 0.121 6 -- (PO4) 18 Sulfate (SO4) mg/L 8.6 <7 <7 400 -- Total 19 Suspended mg/L 11.0 13.0 24.0 10 -- Solids (TSS) 20 Temperature oC 30.2 30.3 30.8 20-30 -- Chemical Oxygen 21 mg/L 8.0 7.0 8.5 4 -- Demand (COD) 77

Note: a: to be usable as a source of water supply only after disinfection; b: to be usable for recreational activity c: to be usable as a source of water supply after conventional treatment; d: to be usable for fisheries e: to be usable for various process and cooling industries f: to be usable for irrigation.

For the first sample, the apparent color, fecal coliform, total coliform, total suspended solids, COD and BOD concentrations exceed the Bangladesh Drinking Water Standard. For the second sample, these parameters and in addition, the true color and turbidity do not satisfy the Standard. For the third sample, color (apparent), turbidity, iron, total coliform, fecal coliform, total suspended solids, COD and BOD concentrations exceed the Bangladesh Drinking Water Standard.

5.4 Water Quality of Balu River

Balu River, approximately 44 kilometers in length, runs mainly through the extensive swamps of Beel Belai and east of Dhaka, joining the Sitalakhya River near Demra. It has a narrow connection through the Suti Nadi near Kapasia with the Sitalakahya, and also by way of the Tongi Khal with the Turag; there is also a link with the Sitalakahya near Kaliganj. Although it carries floodwater from the Sitalakahya and the Turag during the flood season, the Balu is of importance mainly for local drainage and access by small boats. There are a number of industries along this belt of the river resulting to the rapid deterioration of its water quality parameters over the decades. To study the water quality parameters of Balu River, samples were collected from few of the most vulnerable points. Sampling locations of Balu River were Tongi, west side of Tongi Bridge and near Jabar and Jubair textile mills. Samples were collected for the first eight months of 2016 from Tongi; while samples were collected for a period of three months from two other locations of the river. The geographic locations of the sampling locations are shown in Figure 5.11.

Figure 5.11: Sampling stations along Balu River

To study the spatial variation of water quality parameters of Balu, its industrial segmentation has been taken into consideration. Tejgaon is an industrial area with more than 300 industrial units (Roy, 2013). These industries discharge about 12000 m3 untreated wastewater including residue of soap, dyeing, pharmaceuticals and metals industries per day directly into Begunbari and Norai canal which carries the waste through Balu river and ultimately discharges into the Sitalakhya river. Thus Balu River and its canal system is the most polluted area which is responsible for polluting Sitalakhya River; this seriously affects the performance of Saidabad Water Treatment Plant, which draws raw water from Sitalakhya River. Water quality parameters including color, odor, pH, total dissolved solids (TDS), dissolved oxygen (DO), ammonium (NH4) during January to June, 2014 have been studied. Results show that except pH all the parameters exceeded standard limit for domestic water use. The pH of the 4 sampling points of Balu River ranges from 7.28 to 7.33 that are within the range of the domestic water standard. The TDS at different sampling points ranged 982 - 1015 mg/L indicating that this TDS value has increased significantly. The DO values were recorded since 1989 (DoE, 2003) ranging from 0.33 to 2.12 ppm at different points, these values are much below the critical level of 4 mg/L. The ammonium (NH ) at different sampling points ranged from 6.79 – 27.58 mg/L whereas NH 4 4 concentration above 0.05 ppm is vulnerable for human health (ADB, 1994); high ammonia concentration is also toxic to aquatic ecosystem. The results revealed that TDSand NH of Balu 4 River are very high and DO is very low, indicating very high level of pollution of this river. Table 5.4 shows the water quality parameters at sampling sites of Balu River for the year 2016.

Table 5.4: Four water quality parameters of Balu River Water Sampling Sampling Sampling Sampling Sampling Quality point1 point2 point3 point4 Point5 Parameters TDS(mg/l) 1015 1010 1006 982 1020 pH 7.33 7.33 7.31 7.28 7.41 NH4(mg/l) 27.58 22.47 14.45 6.79 19.25 DO(mg/l) 0.37 1.21 1.66 2.12 0.97

The pH of Balu river has been analyzed in the study. The pH along the river reach is shown in Figure 5.12. The plot shows that pH value was within the EQS limit (6.5-8.5 mg/l) for inland surface water with maximum pH value near the Tongi bridge area and minimum at the Demra in the year 2016.

pH along the reach of Balu River Ichapur Bazar(u/s) 8 West of Tongi Bridge 6

4 Jabar and Jubair textile pH mills 2 Nagar Para

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Demra Month

Figure 5.12: pH along the Balu River during 2016 DO

DO concentration was nil at all locations of Balu River from January to May of 2016. This is mostly likely due to discharge of untreated industrial and domestic waste directly or indirectly into the river. Table 5.5 shows the measured DO Sample collected at Balu River for a stretch of 42 km for the year 2016. Figure 5.13 shows the graphical representation of the DO concentration throughout the year. Table 5.5: DO Sample of Balu River for a stretch of 42 km

Location(Latitude) Longitude DO(mg/l) 25 52 56.2 90 27 39.2 0.24 23 52 31.5 90 27 50.4 0.19 23 52 08 90 28 13.4 0.16 23 51 40.9 90 28 31.5 0.19 23 51 10.4 90 28 27.8 1 23 50 35.4 90 28 19.9 0.16 23 50 12.4 90 28 37.6 0.22 23 49 50.9 90 28 59 0.21 23 49 44.3 90 29 12.7 0.17

Location(Latitude) Longitude DO(mg/l) 23 49 22.9 90 29 11.4 0.14 23 48 52.2 90 29 4.5 0.14 23 48 21.5 90 29 3.8 0.16 23 48 2 90 28 54.3 0.16 23 47 54 90 28 52.3 0.15 23 47 22.5 90 28 40.9 0.17 23 47 11.2 90 28 22.4 0.18 23 47 8.7 90 28 18.1 0.18 23 46 44.7 90 28 23.9 0.16 23 46 32.3 90 28 47.8 0.18 23 45 49.2 90 28 56.8 0.25 23 45 38.2 90 28 58.3 0.15 23 45 10.9 90 29 15.2 0.20 23 44 46.3 90 29 18.6 2.11 23 44 40 90 29 32 1.90

5 Spatial Distribution of DO of Balu River DO(mg/l) 4 Critical

3 DO(mg/l)

1 DO(mg/l) 0 1 6 11 16 21 Location Figure 5.13: Spatial Variation of Dissolved Oxygen along the Balu River reach of 42 km

BOD and TDS

BOD at different locations of Balu River varied from 2.1 to 38 mg/l that exceeds the allowable limit for inland discharge as shown in Figure 5.14. Considering the five locations, maximum BOD is observed near the Tongi Bridge and minimum near the Nagar Para area except for the month of February. The high BOD value at different location is primarily due to discharge of domestic waste water (human waste and food waste) and industrial waste water (from tannery, textile and food processing industries). Standard level of BOD for inland surface water for fisheries is 6 mg/l or less.

BOD Ichapur Bazar(u/s)

25 West of Tongi Bridge

Jabar and Jubair textile 15 mills 10 BOD(mg/l) Nagar Para 5

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Demra Month

Figure 5.14: BOD along the Balu River

TDS level was below the EQS limit except at West side of Tongi Bridge (1100 mg/l) in February as shown in Figure 5.15. During both the dry and wet period the river carries maximum TDS near the Tongi Bridge area and minimum near the Nagar Para area.

TDS along the reach of Balu River Ichapur Bazar(u/s) 800 700 West of Tongi Bridge 600

500 Jabar and Jubair textile 400 mills

TDS TDS (mg/l) 300 200 Nagar Para 100

0 Demra Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

Figure 5.15: TDS along the Balu River

Turbidity and Chloride

From Figure 5.16, it can be observed that turbidity level at all locations of Balu River was higher in dry season (Jan-May). Turbidity was under the drinking water standard (10 NTU) from June to August. Discharging of untreated wastewater from industries was the prime cause of high turbidity in dry season. Similar plot have been prepared for the Chloride level, which shows that Chloride concentration was far below the EQS limit (150-600 mg/l) for drinking water.

Maximum (38 mg/l) and minimum (4.5 mg/l) value was found at Tongi (February and March) and near Jabar and Jubair textile mills respectively.

Chloride

250 200 150 100 50 Chloride(mg/l) 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

tongi bridge Ichapur Bazar J&J textile mill Demra Nagar Para

Figure 5.16: Chloride (top) along the Balu River

5.5 Water Quality of Sitalakhya River

Sitalakhya River (also known as Lakhya River) is a distributary of the Brahmaputra which has changed its course at least twice in the Bangladesh region in the fairly recent past, indirectly affecting the flow of water in the Sitalakhya. In its initial stages it flows in a southwest direction and then east of the city of Narayanganj in central Bangladesh until it merges with the Dhaleswari near Kalagachhiya. A portion of its upper course is known as Banar River. The river is about 110 kilometres long and at its widest, near Narayanganj (300 metres) across. Its flow, measured at Demra, has reached 74 cubic metres per second (2600 cu ft/s). It remains navigable year round. The river flows through Gazipur district forming its border with Narsingdi for some distance and then through Narayanganj District.The river's maximum depth is 21 metres and average depth is 10 metres. For analyses water quality of Sitalakhya river water sample was collected from three different locations namely- DemraGhat, Ghorasal Fertilizer Factory (Ghorasal F. F.) and ACI in 2016. The locations are shown in Google earth as follows in Figure 5.17.

Figure 5.17: Water Quality Sampling Stations for Sitalakhya River pH

It has been observed that pH level of the river throughout the year was within the standard limit for inland surface water (6.5-8.5 mg/l). Maximum pH was 7.49 in April at Demra Ghat and minimum pH was 6.8 mg/l in December at Ghorasal F.F as shown in Figure 5.18. The pH was found to vary from 7.12 to 8.3 during the period of 2002-2014 at three points of the river.

pH along the reach of Shitalkhya River 9 8.5 8 7.5 Ghorashal

7 pH ACI Factory 6.5 6 Demra 5.5 5 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

Figure 5.18: pH of Sitalakhya River for the year 2016

BOD and DO

Biochemical Oxygen Demand (BOD) at Demra Ghat and ACI points was very high during dry period of 2016. BOD was within the EQS (6 mg/l or less) throughout the year at Ghorasal. Highest value of BOD was found at Demra Ghat (24 mg/l) in March and lowest value of BOD was found at Ghorashal F.F (2.4 mg/l) in April and May (Figure 5.19). BOD concentration was higher at Demra Ghat compared to the other two locations of the river but maximum level 14.2 mg/l was found at Ghorashal point during the period of 2002-2006 (Ahmed, 2009).

BOD(mg/l) along the reach of Sitalakhya River 40 35 30

25 Kanchpur Bridge 20 Demra 15 BOD(mg/l) ACI Factory 10 5 Ghorashal 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

Figure 5.19: BOD of Sitalakhya River 2016

No Dissolved Oxygen (DO) was found at Demra Ghat from January to February and March. Also at ACI, DO was found to be very low from February to April and then it began to improve towards June to July. DO level was good enough at all locations from August to December. Maximum level of DO was found at Ghorashal F.F (6.8mg/l) in August and October. Between the period of 2002-2014 DO level was not satisfactory at any point; lowest DO (3.9 mg/l) was found at the Ghorashal point during April-May. In 2016 DO varied from 0 to 6.5 mg/l. Concentration of DO in 2016 is presented in Figure 5.20. Direct discharge of untreated effluent from industry, domestic wastes and low availability of water in dry season are the main reason for low level of DO.

DO along the reach of Sitalakhya River 6

4 Kanchpur Bridge

3 Demra DO(mg/l) 2 ACI Factory

1 Ghorashal 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

Figure 5.20: DO concentration of Sitalakhya River for 2016

Turbidity and Alkalinity

Turbidity of the river varied from 6 to 6.5 NTU whereas standard limit is 10 NTU as shown in Figure 5.21.The value of turbidity in NTU was found lowest near the Ghorashal that is below 10 NTU for the maximum months of the year 2016.The river water was more turbid near the Kanchpur Bridge compared to the other locations and the value rises to more than 40 NTU during the month of August and September.

Turbidity (NTU) along Sitalakhya River 50

40 Kanchpur Bridge 30 Demra 20 ACI Factory Turbidity(NTU) 10 Ghorashal

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Figure 5.21: Turbidity of Sitalakhya River for the year 2016 Figure 5.22 shows the alkalinity at 4 locations along the Sitalakhya river, which shows that the alkalinity at the Kachpur bridge exceeds 450 mg/l even during the rainy season. Like all other parameters (except DO) alkalinity is minimum near the Ghorashal area which is below 100 mg/l for most of the months of the year.

Alkalinity along Sitalakhya River 600

500

400 Kanchpur Bridge 300 Demra 200 ACI Factory Alkanity(mg/l) 100 Ghorashal

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Figure 5.22: Total Alkalinity of Sitalakhya River for 2016

TDS and Chloride

Figure 5.23 shows the variation of Total Dissolved Solid (TDS) in 2016. Maximum value of TDS was found at Demra Ghat (420mg/l) in February and minimum at ACI (80mg/l) in November. TDS concentration was within the EQS limit at all locations of the river. Chloride concentration of the river in 2016 was also below the limit of EQS standard for drinking water (150-600 mg/l). Maximum concentration of chloride was found at Ghorasal F.F (18mg/l) in April and minimum concentration at Demra Ghat (4mg/l) in November 2016 as shown in Figure 5.23.

TDS Chloride Kanch 500 Kanch 20 pur pur Bridge 400 Bridge Demra Demra 15

300 ACI ACI 10 Factor 200 Factor

TDS(mg/l) y y Ghoras Chloride(mg/l) 100 Ghora 5 hal shal 0 0 Jul Jan Jun Oct Apr Feb Sep Dec Aug Nov Mar Jul May Jan Jun Oct Apr Feb Sep Dec Aug Nov Mar May Month Month

Figure 5.23: TDS (left) and Chloride (right) of Sitalakhya River for 2016

5.6 Water Quality of Turag River The Turag River is the upper tributary of the Buriganga. There is shortage of data to represent water quality of Turag. Water samples were collected from “Near Ijtema Field, Tongi” to analysis its water quality in 2016. Data was collected only in the month of January, April, June and July and December of 2016. pH of Turag River varied from 7.14 to 7.6 as shown in Figure 5.24 and was within limit for inland surface water of 6.5 to 8.5. In 2016 pH level varied from 7.18 to 8.24. BOD concentration of Turag River within the sampling period in 2016 was relatively static. Maximum (36 mg/l) and minimum (2.6 mg/l) level of BOD was found in April and July, respectively. During 2005 and 2006 highest BOD level was found to be 12 mg/l (Ahmed, 2009). Chloride level of Turag River was below the EQS of drinking water of 150 to 600 mg/l whereas drinking water standard for Chloride is 150 to 600 mg/l. Maximum 40 mg/l and minimum 6 mg/l Chloride was found in April and July, respectively as shown in Figure 5.25. Turbidity level of Turag River varied from 6.5 to 12.5 NTU while drinking water standard for Turbidity is 10 NTU.

pH 7.6 40 BOD Demra 7.4 35 NIFT

7.2 30 ACI 25 7 Factory 20 pH 6.8 15 EQS 6.6 Ghoras BOD(mg/l) 10 (s6 hal mg/l) 6.4 5 6.2 0 Jul Jul Jan Jun Oct Apr Feb Sep Dec Jan Aug Jun Nov Oct Apr Mar Feb Sep Dec May Aug Nov Mar May Month Month

Figure 5.24: pH(left) and BOD(right) along Turag River in 2016

20 Chloride Turbidity Demra Demra 12 Ghat Ghat

10 Dhorasal 15 F.F Ghora 8 shal ACI 10 F.F 6

ACI 4 EQS Chloride(mg/l)

5 Turbidity(NTU) 2 0 0 Jul Jul Jan Jun Oct Jan Apr Feb Sep Jun Dec Oct Apr Aug Feb Sep Nov Dec Mar Aug Nov May Mar May Month Month Figure 5.25: Chloride (Left) and Turbidity (right) along Turag River in 2016

TDS was within the limit at the sampling location. Maximum TDS value was 1000 mg/l found in April while that of minimum was 264 found in June against the EQS of drinking water for TDS is 1000 mg/l as shown in Figure 5.26. DO concentration of Turag River was very low during dry season of 2016 and it was practically nil in January and April of the year 2016.

1200 TDS Demra Ghat

1000 Ghorasal F.F

800

600 ACI

TDS(mg/l) 400 EQS 200

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

Figure 5.26: TDS along Turag River for 2016

5.7 Water Quality of Buriganga River

The Buriganga River is a tide‐influenced river forming the western and southern boundaries of Dhaka City. Originating from the Dhaleshwari River through the Karanatali tributary, the Buriganga’s average width and depth are 400m and 10m respectively. Over the past several years, the river’s length has diminished from 27km to 18km due to siltation and encroachment; 11km of the remaining river flow through Dhaka District and 7km are in Narayanganj District with a very small portion at the river’s terminus in Munshiganj. The present head of the Buriganga near Chaglakandi has silted up and opens only during floods, but the lower part is still open throughout the year. The downstream junction with the Dhaleshwari fluctuates from time to time according to changes in the position of the latter river. Its course by Dhaka is stable, fixed by the resistant clays. Despite the critical role of the Buriganga River in supporting and sustaining the development of Dhaka, it is the most polluted river in the country. This river is struggling for its existence, and it is under threat of becoming a “Dead River.” Water quality parameters collected from the Department of Environment for eight different locations of the river e.g. Mirpur Bridge, Hazaribag, Kamrangir Char, Chandni Char, Sadarghat, Dholaikhal, Bangladesh China Friendship Bridge, and Pagla have been processed to analyze the spatial variation of the parameters. Locations selected for the analysis are summarized in following table and Figure 5.27 shows the locations of Buriganga River on Google Earth.

Table 5.6: Locations of water quality parameters of Buriganga River River Name Locations Buriganga Mirpur Bridge Buriganga Hazaribag Buriganga Kamrangir Char Buriganga ChandniGhat Buriganga SadarGhat Buriganga Dholaikhal Buriganga B.C.F. Bridge

Buri Ganga

Figure 5.27: Sampling Locations of Buriganga River pH

As shown in Figure 5.28 pH level varies from 6.5 to 8 in 2016 while standard limit for inland surface water pH is 6.5 to 8.5; the values are within the for drinking water standard set by ECR 1997.

8 pH 7 Mirpur Bridge 6 Hazaribag 5 Kamrangir Char

pH 4 Chandni Ghat 3 Sadar Ghat 2 Dholaikhal 1 B.C.F. Bridge* 0 Pagla Jan Feb Mar Apr May Jun Jul Agu Sep Oct Nov Dec Month

Figure 5.28: pH along Buriganga River for 2016 (Data source: DoE)

Chlorine

Figure 5.29 represents Chloride level at various location of Buriganga River. Chloride level was found between the ranges of 6-48 mg/l in 2016 and was mostly within the EQS limit. But from January to April, Chloride level exceed the EQS at Hazaribag. Also at Dholaikhal point it exceeds the limit in March and April. Chloride along the reach of Buriganga River 70 Mirpur Bridge 60 Hazaribag 50 Kamrangir 40 Char Chandni Ghat 30 Sadar Ghat

20 Dholaikhal

Chloride(mg/l) 10 B.C.F. Bridge*

0 Pagla Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

Figure 5.29: Chloride along Buriganga River for 2016 (Data source: DoE)

Turbidity and TDS

Turbidity level varied from 6 to 18.5 NTU and was mostly within the EQS limit. But from January to April turbidity level exceed the EQS at Hazaribag. Also at Dholaikhal point turbidity exceeds the limit in March and April. TDS of Buriganga River varied from 22 to 2050 mg/l against the EQS of 1,000 mg/l for drinking water. In dry season TDS limit was very high at Hazaribag, Kamrangir Char and Dholaikhal sampling locations. TDS level varied from 149 to 1188 mg/l in 2016.

Turbidity(NTU) along the reach of Buriganga River

Mirpur Bridge 15 Hazaribag

Kamrangir Char 10 Chandni Ghat Sadar Ghat 5 Dholaikhal Turbidity(NTU) B.C.F. Bridge* 0 Pagla Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

Figure 5.30: Turbidity along Buriganga River for 2016 (Data source: DoE)

TDS along the reach of Buriganga River 2500 Mirpur Bridge

2000 Hazaribag

Kamrangir 1500 Char Chandni Ghat

1000 TDS(mg/l) Sadar Ghat

Dholaikhal 500 B.C.F. Bridge* 0 Jan Feb Mar Apr May Jun Jul Agu Sep Oct Nov Dec Month

Figure 5.31: TDS along Buriganga River for 2016 (Data source: DoE)

DO and BOD

Dissolved oxygen (DO) in Buriganga River was very low in 2016. In first five months, DO level was about nil at all location of the river. Hazaribug and Dholaikhal points of Buriganga River did not meet the DO standard for fisheries (≥5 mg/l) all over the year. In 2006 DoE found DO level was below 5 mg/l in April to May and July to August and in 2016 DO level varied from 0 to 5.1 mg/l. This is mainly because of direct discharge of tannery waste into the river at those points. About 183 tanneries of Hazaribagh release 2,500 gallons of chemical wastes each day into Buriganga. DO level was relative higher in wet season at all locations of the river.

DO (mg/l) along the reach of Buriganga River 6

5 Mirpur Bridge Hazaribag 4

Kamrangir Char 3 Chandni Ghat DO(mg/l) 2 Sadar Ghat Dholaikhal 1 B.C.F. Bridge* 0 Pagla Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

Figure 5.32: DO along Buriganga River for 2016 (Data source: DoE) BOD concentration of Buriganga River was very high in most of the months of 2016. During wet season, BOD concentration was decreased and at some points of the Buriganga River meet BOD standard for fisheries (≤6 mg/l). But at Hazaribag point BOD level was higher than standard limit all over the year. This is mainly because of high rate of discharge of tannery waste into the river at this point. Maximum BOD (44 mg/l) was found at Hazaribag in April and minimum (2.2 mg/l) was at Dholaikhal in September.

BOD along the reach of Buriganga River 30 Mirpur 25 Bridge Hazaribag 20 Kamrangir Char 15 Chandni Ghat BOD(mg/l) 10 Sadar Ghat

5 Dholaikhal

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

Figure 5.33: BOD along Buriganga River for 2016 (Data source: DoE)

5.8 Water Quality of Dhaleshwari River The Dhaleshwari River is a 160-km-long distributary of the Jamuna River in central Bangladesh (BWDB, 2010). It starts off the Jamuna near the northwestern tip of Tangail. After that it divides into two branches: the north branch retains the name Dhaleshwari and merges with the other branch, the Kaliganga River at the southern part of Manikganj District. Finally the merged flow meets the Sitalakhya River near Narayanganj District. This combined flow goes southwards to merge into the Meghna River.Water samples were collected from one location for analyses. In most cases, Water quality parameters were within the EQS limit. pH of Dhaleshwari River varied from 6.8 to 7.2 in 2016. Maximum and minimum level was found in April and July respectively. Again, Chloride concentration varied from 3.5 to 12 mg/l which is far below the EQS limit (150-600 mg/l) for drinking water. Turbidity level varied from 6 to 6.5 NTU against the EQS of 10 NTU for drinking water around the year. TDS concentration varied from 54 to 150 mg/l while drinking water standard for TDS is 1000 mg/l. Moreover, DO concentration of Dhaleshwari River critically met the limit for fisheries during January to May. Then DO level goes up from June towards December. Level of DO varied from 4.8 to 6.9 mg/l in 2016. BOD value of Dhaleshwari River in 2016 varied from 2.8 to 3.8 mg/l while standard for BOD for fisheries is 6 or below 6 mg/l. Graphical representation of water parameters are given in Figure 5.34.

pH 7 8 Turbidity 6 7

5 6

4 5 Measured Value pH 3 MV 4 (MV) 3 2 EQS (s6 mg/l)

Turbidity(NTU) 2 1 1 0 0 Jul Jan Jun Oct Jul Apr Feb Sep Dec Aug Nov Mar Jan Jun May Oct Apr Feb Sep Dec Aug Nov Mar Month May Month

TDS DO 1000 12 800

600 MV 6 MV 400 Standar DO(mg/l) TDS(mg/l) EQS d 3 200

0 0 Jul Jul Jan Jun Oct Apr Feb Sep Dec Jan Aug Jun Nov Oct Mar Apr Feb Sep Dec May Aug Nov Mar May Month Month

Figure 5.34: Water quality parameters along Dhaleswari River for 2016

5.9 Yearly Variation of Water Quality Parameters of the River System Obtained data from DOE, WARPO and BWDB has been processed to analyze the trend of the parameters of the rivers of Dhaka city over the years during 1990 to 2016. BOD of the peripheral rivers of Dhaka have been plotted to have an idea on the trend of pollution. The plot shows that BOD of the Balu, Buriganga and Tongi khal is comparatively greater than the Dhaleshwari and Sitalakhya rivers for all the years considered.

BOD and DO

Figure 5.35 shows that the BOD concentration of different rivers as a function of time (from 1995 to 2016). It shows an increasing trend for almost all the rivers.

BOD in peripheral rivers of Dhaka Balu (Demra) 28 26 Turag (Mirpur) 24 22

20 Shitalakhya 18 16 (Sarulia) 14 Buriganga (Mill 12 Barak)

BOD(mg/l) 10 8 Tongi khal 6 4 (Tongi) 2 Dhaleshwari 0 (Kalagachia) 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2016 Year

Figure 5.35: Trend of BOD in peripheral rivers of Dhaka City

Turbidity Figure 5.36 shows that the turbidity in NTU is low for all the rivers except the Buriganga and Sitalakhya. Maximum value of turbidity was obtained for the Buriganga during the year 1995 and overall the plot shows a decreasing trend. In case of Sitalakhya turbidity was around 200 NTU to 300 NTU for the years ranging from 2001 to 2016.For the other rivers turbidity is below 40 NTU as shown in Figure 5.37. Turbidity in peripheral river system Balu 900 800

Turag 700 600 500 Shitalakhya 400 300 Buriganga

Turbidity(NTU) 200 100 Tongi khal 0 1990 1995 2000 2005 2010 2015 Dhaleshwari Year

Figure 5.36: Trend of Turbidity in peripheral rivers of Dhaka City

pH Figure 5.37 shows the trend of pH in all the peripheral rivers of Dhaka city which depicts that pH of the peripheral river are within the range of 6.5 to 8.5 throughout the years. Buriganag river water shows comparatively higher pH value than the others.

pH in peripheral river system Balu 12 Turag 10

8 Shitalakhya pH 6 4 Buriganga 2 0 Tongi khal 1900 1995 2000 2005 2010 Year Dhaleshwari

Figure 5.37: Trend of pH in peripheral rivers of Dhaka City

Chloride Figure 5.38 shows the trend of chloride in all the peripheral rivers of Dhaka city which depicts that chloride of the peripheral rivers vary over a wide range Chloride in peripheral river system Balu (Demra) 200 Turag (Mirpur) 150

Shitalakhya 100 (Sarulia) Buriganga (Mill 50 Barak) Tongi khal

Chloride(mg/l) (Tongi) 0 Dhaleshwari 1990 1995 2000 2005 2010 2015 (Kalagachia) Year

Figure 5.38: Trend of Chloride in peripheral rivers of Dhaka City

Heavy Metals Peripheral rivers of Dhaka City receive large quantity of untreated sewage, industrial liquid and municipal waste everyday which leads to serious surface water contamination. It is very important to focus on the status of heavy metal in those peripheral rivers. In this section five

different parameters, Cd, Cr, Ni, Pb and Zn are considered for statistical analysis and for comparison with the Bangladesh standards for water. Change of Cadmium, chromium, nickel, lead and zinc concentration in peripheral rivers around Dhaka city in dry seasons from 1997 till 2016 are plotted in Figure 5.40 to Figure 5.44.The figure indicates that maximum cadmium concentration in the peripheral rivers was in 1998 and minimum in 2006 and after 2006 concentration rises.

Cd Concentration of peripheral river system Balu (Demra) 0.18

0.16 Turag (Mirpur) 0.14 0.12 Shitalakhya 0.1 (Sarulia) 0.08 Buriganga (Mill

Cd(mg/l) 0.06 Barak) 0.04 0.02 Tongi khal (Tongi) 0 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016 Year

Figure 5.40: Trend of Cadmium in peripheral rivers of Dhaka City By analyzing the variation of Chromium from the year 1994 to 2016 it has been found that the highest value of Chromium is found in 2016 in Balu river which is 0.73 mg/l. Considering drinking purposes peripheral river water is not suitable for drinking because of high concentration of chromium.

Cr concentration of peripheral river system 0.3 Balu (Demra)

0.25 Turag (Mirpur) 0.2 Shitalakhya 0.15 (Sarulia)

Buriganga (Mill Cr(mg/l)

0.1 Barak)

0.05 Tongi khal (Tongi)

0 1990 1995 2000 2005 2010 2015 Year

Figure 5.41: Trend of Chromium in peripheral rivers of Dhaka City

Lead concentration in 1997, 1998 and 2006 shows that at almost all the selected rivers are higher in concentration than the Standards for Drinking Water, (ECR, 97). Pb concentration of peripheral river system 0.5 Balu (Demra)

0.4 Turag (Mirpur) 0.3 Shitalakhya (Sarulia) 0.2 Buriganga Pb(mg/l) 0.1 (Mill Barak) Tongi khal 0 (Tongi) 1995 2000 2005 2010 2015 Year

Figure 5.42: Trend of Pb in peripheral rivers of Dhaka City The highest Concentration of Zn was found in Buriganga River in 1997 and 2005. The values are 4.6mg/l and 4.57 mg/l respectively. These Values are lower than Bangladesh standards for drinking water

Figure 5.43: Trend of Zn in peripheral rivers of Dhaka City Concentrations of the selected heavy metals are higher than Bangladesh Standards for Drinking water in most of the cases for the five selected peripheral water bodies. This is mainly because of the discharge of municipal waste water and effluent from the industries established in unplanned way near the river side.

100

Ni concentration of peripheral river system 0.16 Balu (Demra) 0.14 0.12 Turag (Mirpur)

0.1 0.08 Shitalakhya 0.06 (Sarulia) Ni (mg/l) 0.04 Buriganga (Mill Barak) 0.02 Tongi khal 0 (Tongi) 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016

Year

Figure 5.44: Trend of Nickel in peripheral rivers of Dhaka City

5.10 Summary of Pollutant Concentration of Surface Water System of Dhaka City Table 5.7 to Table 5.19 show the summary of Pollutant concentration in the Peripheral Rivers for the year 2004 and 2016 which provides a clear idea on the increasing trend of pollutant. Table 5.7: Summary of pH Values

River Name pH (Drinking and Inland River Water Standard 6.5-8.5) Jan Feb Mar Apr May Jun July Aug Sep Oct Nov Dec Turag (Mirpur) 7.2 7.3 7.3 7.4 7.4 7 6.9 6.9 6.8 6.8 7.2 6.9 Balu (Demra) 6.5 6.66 6.7 6.3 6.7 7 7.1 6.5 6.66 6.9 7.1 6.7 Sitalakhya(Sarulia) 6.8 7 7.2 7.3 7.1 7.2 7 6.9 7.3 7 7.1 7 Buriganga 7.4 7.9 7.8 7.5 7.5 7.5 7 7 7 6.3 7.5 7.6 (Mill Barak) Dhaleshwari 5 5 5 5 5 5.8 6.5 6.5 6.9 6.8 6.5 6.2 (Kalagachia) Tongi Khal (Tongi) 7.2 7.7 7.5 7.2 7.5 7.6 7.5 7.7 7.1 7.2 7.5 7.5 Padma (Jasaldia) 7.1 7.4 7.5 7.9 8.1 7.8 7.4 7.5 7.9 7.7 7.2 7.9 Meghna(Meghna ghat) 7 6.9 7.7 7.9 7.9 7.1 7.3 7.1 7.6 7.1 7.3 7.2 Table 5.8: Summary of Turbidity Values

River Name Turbidity (Drinking Standard 10 NTU) Jan Feb Mar Apr May Jun July Aug Sep Oct Nov Dec Turag (Mirpur) 7 7 7 6 6 6 6 7 7 6 6 7 Balu (Demra) 10 8 6.5 6.5 6 6.4 6.5 6.5 6.5 6.5 6.7 6.3 Sitalakhya (Sarulia) 8 8 7 9 9 10 10 10 9 9 8 8 Buriganga (Mill 10 8 7.2 6.5 6.5 6.7 6.9 6.5 6.5 6.5 6.5 6.5 Barak) Dhaleshwari 7.1 7.1 7.2 7.3 6.7 6.8 6.7 6.8 6.7 6.7 6.8 6.7 (Kalagachia) Tongi Khal (Tongi) 7.5 8 8.1 7.9 7.8 7.6 8.1 7 7 7 7.2 7 Padma 4.2 5.9 4.4 5.8 4.2 5.9 4.2 5.7 4.3 5.9 4.8 5.8 Meghna 6.5 5.9 5.7 6.4 5.9 5.7 6.3 5.9 5.8 6.3 5.9 5.3 101

Table 5.9: Summary of Chloride Values

River Name Chloride (Drinking Standard 150-600 mg/l) Jan Feb Mar Apr May Jun July Aug Sep Oct Nov Dec Turag (Mirpur) 18 16 17 18 14 12 9 7 10 7 7 7 Balu (Demra) 167 172 171 170 168 162 168 173 171 171 174 160 Sitalakhya (Sarulia) 18 16 17 19 17 15 10 8 10 6 6 6 Buriganga (Mill 175 150 175 150 175 150 175 150 175 150 175 150 Barak) Dhaleshwari 10 15 16 17 11 9 8 6 7 6 5 6 (Kalagachia) Tongi Khal (Tongi) 8 8 8 10 10 10 11 7 7 7 7 7 Padma 118 121 123 121 126 138 130 126 117 115 123 121 Meghna 178 177 172 184 194 189 186 182 173 171 164 170

Table 5.10: Summary of Ammonia Values

River Name NH4 ((Drinking Standard 0.5 mg/l ) Jan Feb Mar Apr May Jun July Aug Sep Oct Nov Dec Turag (Mirpur) 0.44 0.48 0.40 0.27 0.28 0.41 0.22 0.35 0.27 0.24 0.22 0.20 Balu (Demra) 2.58 2.47 1.45 1.79 0.25 0.58 0.47 0.45 0.49 0.25 0.79 1.25 Sitalakhya (Sarulia) 0.63 0.53 0.43 0.22 0.23 0.29 0.27 0.30 0.27 0.28 0.48 0.50 Buriganga (Mill 0.23 0.23 0.23 0.23 0.23 0.23 0.23 0.354 0.274 0.274 0.274 0.274 Barak) Dhaleshwari 0.21 0.23 0.23 0.21 0.23 0.23 0.23 0.354 0.274 0.274 0.274 0.274 (Kalagachia) Tongi Khal (Tongi) 0.30 0.26 0.50 0.22 0.40 0.23 0.23 0.354 0.274 0.274 0.274 0.274 Padma 0.21 0.27 0.41 0.22 0.45 0.19 0.20 0.35 0.27 0.274 0.274 0.274 Meghna 0.24 0.29 0.31 0.20 0.23 0.23 0.23 0.354 0.274 0.274 0.274 0.274

Table 5.11: Summary of DO

River Name DO (Inland River Water Standard 6 mg/l) Jan Feb Mar Apr May Jun July Aug Sep Oct Nov Dec Turag (Mirpur) 5.2 5.3 5.6 5.1 5.7 5.7 5.8 5.9 6.0 5.9 7.3 6.9 Balu (Demra) 4 5 5.3 5.2 3.5 5.4 5 5.6 6.5 6.1 7.5 7 Sitalakhya (Sarulia) 4 3 4 2 3 5 4 3 2 3 2 3 Buriganga (Mill 4 3.5 3.5 4 4 4 4.5 3.5 4.5 4.5 3.5 4 Barak) Dhaleshwari 4.9 4.7 4.2 3.6 3.8 4.9 4.7 4.2 3.6 3.8 4.3 4.5 (Kalagachia) Tongi Khal (Tongi) 5.6 4.5 3.9 4.6 3.5 4.1 6 7 6.7 7 6.7 7.8 Padma 5.00 5.40 5.50 5.20 5.80 5.70 5.00 5.40 5.50 5.20 5.80 5.70 Meghna 3.70 3.90 4.90 4.50 3.70 3.90 4.90 4.50 3.70 3.90 4.90 4.50

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Table 5.12: Summary of BOD Parameter

River Name BOD (Inland River Water Standard: 2 mg/l; Drinking Standard 0.2 mg/l) Jan Feb Mar Apr May Jun July Aug Sep Oct Nov Dec Turag (Mirpur) 6.00 6.50 5.80 6.00 6.11 5.49 5.11 5.76 6.22 6.14 5.99 6.71 Balu (Demra) 23.00 26.00 14.1 13.8 11 18 13 15 19 13 10 9.1 Sitalakhya (Sarulia) 14.00 16.00 11.00 12.00 9.00 3.00 2.40 2.40 3.30 10.40 12.0 10.0 Buriganga (Mill 22 4 22 5 24 24 10 12.5 10 10 5.5 7.2 Barak) Dhaleshwari 0.9 0.8 0.8 0.7 0.9 0.9 0.8 0.9 0.6 0.6 0.7 0.7 (Kalagachia) Tongi Khal (Tongi) 1.4 3.9 2.1 4.1 1.4 3.9 2.1 4.1 1.4 3.9 2.1 4.1 Padma 0.5 0.7 0.1 0.2 0.6 0.8 0.7 0.1 0.1 0.6 0.7 0.3 Meghna 0.7 0.5 0.6 0.9 0.2 0.9 0.1 0.3 0.2 0.02 0.3 0.8

Table 5.13: Summary of TDS Parameter

River Name TDS (Drinking Standard 1000 mg/l) Jan Feb Mar Apr May Jun July Aug Sep Oct Nov Dec Turag (Mirpur) 400 400 400 340 280 180 100 90 120 90 130 210 Balu (Demra) 689 566 656 641 620 600 623 655 672 689 720 710 Sitalakhya (Sarulia) 400 410 400 380 300 200 160 100 100 120 140 200 Buriganga (Mill 560 550 1400 1295 920 360 320 304 350 370 240 480 Barak) Dhaleshwari 160 180 175 180 160 130 90 100 90 80 90 65 (Kalagachia) Tongi Khal (Tongi) 160 210 100 210 110 100 100 90 90 90 90 100 Padma 600 605 618 567 570 530 516 529 546 571 609 589 Meghna 600 605 618 567 570 530 516 529 546 571 609 589

Table 5.14: Summary of Lead (Pb) Parameter

River Name Lead (Pb) (Drinking Standard 0.05 mg/l) Jan Feb Mar Apr May Jun July Aug Sep Oct Nov Dec Turag (Mirpur) 0.09 0.08 0.04 0.06 0.08 0.03 0.055 0.025 0.035 0.04 0.045 0.08 Balu (Demra) 0.06 0.01 0.06 0.07 0.04 0.035 0.05 0.045 0.040 0.05 0.06 0.06 Sitalakhya (Sarulia) 0.04 0.05 0.06 0.07 0.02 0.021 0.0206 0.028 0.08 0.045 0.08 0.07 Buriganga (Mill 0.06 0.07 0.08 0.07 0.045 0.04 0.045 0.05 0.050 0.05 0.09 0.08 Barak) Dhaleshwari 0.026 0.028 0.025 0.026 0.02 0.021 0.0206 0.028 0.025 0.026 0.028 0.025 (Kalagachia) Tongi Khal (Tongi) 0.07 0.08 0.09 0.07 0.013 0.02 0.023 0.033 0.04 0.013 0.08 0.07 Padma 0.01 0.005 0.02 0.03 0.001 0.002 0.004 0.034 0.033 0.035 0.04 0.03

Meghna 0.01 0.02 0.01 0.03 0.005 0.006 0.007 0.034 0.04 0.022 0.03 0.04

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Table 5.15: Summary of Cadmium (Cd) Pollution Parameter

River Name Cadmium (Cd) (Drinking Standard 0.005 mg/l) Jan Feb Mar Apr May Jun July Aug Sep Oct No Dec v Turag (Mirpur) 0.006 0.07 0.07 0.07 0.003 0.004 0.005 0.002 0.004 0.003 0.006 0.006

Balu (Demra) 0.06 0.08 0.05 0.08 0.002 0.001 0.003 0.004 0.005 0.003 0.08 0.08 Sitalakhya (Sarulia) 0.08 0.08 0.08 0.08 0.002 0.001 0.003 0.004 0.005 0.003 0.08 0.08 Buriganga (Mill 0.06 0.07 0.03 0.03 0.003 0.004 0.005 0.002 0.004 0.003 0.03 0.03 Barak) Dhaleshwari 0.022 0.022 0.022 0.022 0.022 0.022 0.022 0.022 0.022 0.022 0.022 0.022 (Kalagachia) Tongi Khal (Tongi) 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 Padma 0.002 0.002 0.003 0.001 0.002 0.003 0.001 0.004 0.001 0.002 0.001 0.002 Meghna 0.003 0.001 0.002 0.001 0.003 0.003 0.004 0.003 0.001 0.002 0.001 0.003

Table 5.16: Summary of Chromium (Cr) Pollution Parameter

River Name Chromium (Cr) (Drinking Standard 0.05 mg/l) Jan Feb Mar Apr May Jun July Aug Sep Oct Nov Dec Turag (Mirpur) 0.13 0.13 0.001 0.001 0.001 0.013 0.13 0.13 0.001 0.001 0.001 0.013 Balu (Demra) 0.08 0.07 0.06 0.08 0.05 0.03 0.04 0.08 0.03 0.05 0.08 0.06 Sitalakhya (Sarulia) 0.03 0.04 0.04 0.03 0.02 0.05 0.03 0.05 0.03 0.04 0.05 0.04 Buriganga (Mill 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 Barak) Dhaleshwari 0.04 0.05 0.022 0.05 0.03 0.021 0.021 0.02 0.03 0.021 0.04 0.05 (Kalagachia) Tongi Khal (Tongi) 0.017 0.017 0.017 0.017 0.017 0.017 0.017 0.017 0.017 0.017 0.017 0.017 Padma 0.005 0.004 0.002 0.003 0.005 0.002 0.001 0.004 0.003 0.002 0.003 0.004 Meghna 0.003 0.002 0.001 0.001 0.002 0.003 0.004 0.003 0.005 0.002 0.004 0.003

Table 5.17: Summary of Zinc (Zn) Pollution Parameter

River Name Zinc (Zn) (Drinking Standard 5 mg/l) Jan Feb Mar Apr May Jun July Aug Sep Oct Nov Dec Turag (Mirpur) 2 2.1 2.2 2.2 2 2.3 2.5 2.3 3 3.1 3 3 Balu (Demra) 3 3.5 4 3.5 3.5 3 3.5 3.6 4 4.1 4.1 3.1 Sitalakhya (Sarulia) 3 3.8 3.6 3.8 4 3.6 4 4.1 3.8 3.9 4.1 4 Buriganga (Mill 4.7 4.5 4.2 4.5 4.6 4.2 4.7 5 4.9 4.3 4.4 4.5 Barak) Dhaleshwari 0.02 0.02 0.02 0.02 0.02 0.01 0.02 0.02 0.02 0.02 0.02 0.02 (Kalagachia) Tongi Khal (Tongi) 2.2 2.5 2.6 2.4 2.8 3 3.1 3.1 3 2.9 3 3.1 Padma 0.061 0.028 0.017 0.051 0.028 0.017 0.051 0.051 0.051 0.051 0.051 0.051 Meghna 0.051 0.052 0.050 0.052 0.053 0.050 0.051 0.028 0.018 0.019 0.015 0.017

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Table 5.18: Summary of Mercury (Hg) Pollution Parameter

River Name Mercury (Hg) (Drinking Standard 0.001 mg/l) Jan Feb Mar Apr May Jun July Aug Sep Oct Nov Dec Turag (Mirpur) 0.07 0.08 0.09 0.05 0.06 0.07 0.09 0.04 0.03 0.04 0.06 0.08 Balu (Demra) 0.03 0.02 0.04 0.05 0.06 0.07 0.08 0.09 0.03 0.06 0.07 0.04 Sitalakhya (Sarulia) 0.07 0.08 0.09 0.04 0.05 0.07 0.04 0.07 0.03 0.02 0.07 0.05 Buriganga (Mill 0.03 0.04 0.05 0.06 0.05 0.04 0.03 0.04 0.05 0.06 0.04 0.03 Barak) Dhaleshwari 0.02 0.03 0.04 0.05 0.07 0.08 0.04 0.06 0.05 0.02 0.03 0.04 (Kalagachia) Tongi Khal (Tongi) 0.002 0.001 0.004 0.003 0.002 0.003 0.004 0.0002 0.0001 0.0004 0.0004 0.0002 Padma 0.00 0.001 0.00 0.00 0.001 0.00 0.00 0.00 0.00 0.00 0.00 0.0 1 1 1 1 1 1 1 1 1 01

Meghna 0.00 0.001 0.00 0.00 0.001 0.00 0.00 0.00 0.00 0.00 0.00 0.0 1 1 1 1 1 1 1 1 1 01

Table 5.19: Summary of Phosphate (PO4 ) Pollution Parameter

River Name Phosphate (PO4) ((Drinking Standard 6 mg/l) Jan Feb Mar Apr May Jun July Aug Sep Oct Nov Dec Turag (Mirpur) 0.05 0.02 0.03 0.04 0.067 0.067 0.067 0.081 0.12 0.121 0.121 0.121 Balu (Demra) 0.02 0.03 0.067 0.04 0.05 0.06 0.08 0.09 0.13 0.15 0.14 0.121 Sitalakhya (Sarulia) 0.05 0.02 0.03 0.04 0.067 0.067 0.067 0.081 0.11 0.15 0.16 0.14 Buriganga (Mill 0.02 0.03 0.067 0.04 0.05 0.06 0.08 0.09 0.17 0.141 0.15 0.16 Barak) Dhaleshwari 0.061 0.067 0.067 0.067 0.067 0.067 0.067 0.081 0.12 0.121 0.121 0.121 (Kalagachia) Tongi Khal (Tongi) 0.05 0.02 0.03 0.04 0.067 0.067 0.067 0.081 0.11 0.15 0.16 0.14 Padma 0.063 0.061 0.064 0.062 0.061 0.04 0.02 0.02 0.11 0.15 0.16 0.14 Meghna 0.034 0.062 0.065 0.063 0.062 0.03 0.07 0.05 0.17 0.141 0.15 0.16

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5.11 Collection and Analysis of Water Samples

As a part of this study, water samples have been collected from peripheral rivers during the months of September 2017 and January 2018. These samples were tested in the MIST laboratory for all the water quality parameters. The results are shown in Table 5.20 and Table 5.21.

Table 5.20: Summary of Water Quality Parameter of Samples Collected in September 2017 River Name Sample 1(mg/l) for September 2017 pH Turbidity Cl TDS BOD Cd DO Pb PO4 Zn Cr Hg Turag (Mirpur) 6.8 7.1 7 90 6.22 0.07 5.25 0.05 0.12 0.07 0.06 0.07 Balu (Demra) 7.1 9.8 129 546 11.00 0.08 11.7 0.05 0.13 0.08 0.08 0.08 Sitalakhya 7.1 18 7 100 3.30 0.08 18 0.08 0.11 0.08 0.08 0.08 (Sarulia) Buriganga (Mill 7.3 10 15 350 15.00 0.03 6.50 0.05 0.12 0.03 0.03 0.03 Barak) Dhaleshwari 7.2 17 7 100 11.00 0.022 18.0 0.025 0.13 0.02 0.02 0.01 (Kalagachia) 7 Tongi Khal 7.5 7 7 90 6.22 0.019 5.25 0.013 0.12 0.02 0.01 0.02 (Tongi)

Table 5.21: Summary of Water Quality Parameter of Samples Collected in January 2018 River Name Sample 2(mg/l) for January 2018 pH Turbidity Cl TDS BOD COD DO Pb PO4 Zn Cr Hg Turag (Mirpur) 6.2 6.1 6.9 80 5.22 0.06 4.25 0.04 0.13 0.06 0.06 0.05 Balu (Demra) 6.5 7.8 15 145 8.00 0.07 11.6 0.06 0.14 0.07 0.07 0.06 Sitalakhya 6.3 10 6 90 4.30 0.07 12 0.07 0.13 0.07 0.02 0.07 (Sarulia) Buriganga (Mill 5.9 8 12 85 11.00 0.04 5.50 0.04 0.14 0.04 0.04 0.04 Barak) Dhaleshwari 6.9 10 6.8 88 9.00 0.021 11.0 0.03 0.15 0.03 0.02 0.01 (Kalagachia) Tongi Khal 6.5 6 6.9 78 7.22 0.020 6.25 0.02 0.11 0.04 0.02 0.00 (Tongi) 02

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5.12 Summary and Concluding Remarks Analysis of water quality parameters in Tongi, Balu, Buriganga and Turag rivers suggests that waters from these rivers are not suitable for use as a source of raw water for water treatment. However, water quality of other peripheral rivers at some locations was found good and can be used as potential source of surface water. Table 5.22 has been prepared based on the water quality parameters as shown in Tables 5.7 to 5.19 for all the rivers. When a maximum of three

parameters fail to satisfy the standard, the water has been labeled as ‘Not Recommended (X) s source water for water treatment. a. In Chapter 6, water availability would be discussed and an analysis would be made to fulfill both requirements of quality and quantity to qualify a water source as potential surface water source for water treatment and supply. After analysis of the both criteria (quality and quantity), surface water sources would be suggested for Dhaka city water supply. Table 5.22: Status of Water Quality compared to Standard Limit

Rivers Jan Feb Mar Apr May Jun

Pb, Pb, Pb,Cd, X Pb,Cd, X Cd, X Cd, X BOD X BOD X BOD Turag BOD BOD BOD

      pH,DO, pH,DO, pH,DO,Tubi Tubidity Tubidity dity,cl,NH4, pH,DO,Tubi  pH,DO,  pH,DO,    dity,cl,NH4, Tubidity Tubidity ,cl,NH4, ,cl,NH4, PO4, PO4, etc ,cl,NH4, ,cl,NH4, PO4, PO4, etc etc etc PO4, PO4, etc etc

Pb, Pb, Pb,Cd, X Pb,Cd, X Cd, X Cd, X BOD X BOD X BOD BOD BOD BOD

Tongi Khal      

pH,DO,Tubi  pH,DO,  pH,DO,  pH,DO,  pH,DO,  pH,DO,Tubi  dity,cl,NH4, Tubidity Tubidity Tubidity Tubidity dity,cl,NH4, PO4,etc ,cl,NH4, ,cl,NH4, ,cl,NH4, ,cl,NH4, PO4,etc PO4,etc PO4,etc PO4,etc PO4,etc

BOD BOD Pb, Cd Pb, Cd Pb, Cd Cr, Cr, Pb, Cd Cr, X Cr, X X X X X BOD BOD BOD BOD

Balu pH,DO,Tubi  pH,DO,  pH,DO,  pH,DO,  pH,DO,  pH,DO,Tubi  dity,cl,NH4, Tubidity Tubidity Tubidity Tubidity dity,cl,NH4, PO4,etc  ,cl,NH4,  ,cl,NH4,  ,cl,NH4,  ,cl,NH4,  PO4,etc  PO4,etc PO4,etc PO4,etc PO4,etc

Cd, Cd, Cd, Cd, BOD,NH4 BOD,N BOD,N BOD,N X H4 X H4 X H4 X BOD X BOD X

107

pH,DO,Tubi  pH,DO,  pH,DO,  pH,DO,  pH,DO,  pH,DO,Tubi  dity,cl,NH4, Tubidity Tubidity Tubidity Tubidity dity,cl,NH4, PO4,etc  ,cl,NH4,  ,cl,NH4,  ,cl,NH4,  ,cl,NH4,  PO4,etc  Buriganga PO4,etc PO4,etc PO4,etc PO4,etc

BOD,NH4 X BOD,N X BOD X BOD X BOD X BOD X H4

pH,DO,Tubi  pH,DO,  pH,DO,  pH,DO,  pH,DO,  pH,DO,Tubi  dity,cl Tubidity Tubidity Tubidity Tubidity dity,cl,PO4, Sitalakhya ,PO4,etc  ,cl,  ,cl  ,cl,PO4,  ,cl,PO4,  etc  PO4,etc ,PO4,et etc etc c

BOD X BOD X BOD X BOD X BOD X BOD X

pH,DO,Tubi  pH,DO,  pH,DO,  pH,DO,  pH,DO,  pH,DO,Tubi  dity,cl,NH4, Tubidity Tubidity Tubidity Tubidity dity,cl,NH4, PO4,etc  ,cl,NH4,  ,cl,NH4,  ,cl,NH4,  ,cl,NH4,  PO4,etc  Dhaleshwari PO4,etc PO4,etc PO4,etc PO4,etc 

pH,  pH,  pH,  pH,  pH,  pH,BOD,D  BOD,DO,Tu BOD,D BOD,D BOD, BOD,D O,Tubidity,c bidity,cl,NH  O,Tubid  O,Tubid  DO,Tub  O,Tubid  l,NH4,PO4,  Padma 4,PO4,etc ity,cl,N ity,cl,N idity,cl, ity,cl,N etc H4,PO4 H4,PO4 NH4,P H4,PO4 ,etc ,etc O4,etc ,etc

pH,DO,Tubi  pH,BO  pH,BO  pH,BO  pH,BO  pH,BOD,D  dity,cl,NH4, D,DO,T D,DO,T D,DO,T D,DO,T O,Tubidity,c PO4,etc  ubidity,c  ubidity,c  ubidity,c  ubidity,c  l,NH4,PO4,  Meghna l,NH4,P l,NH4,P l,NH4,P l,NH4,P etc O4,etc O4,etc O4,etc O4,etc

Contd. Rivers Jul Aug Sep Oct Nov Dec

Pb, Cd Pb, Cd Cr, Cr, BOD BOD X BOD X BOD X BOD X BOD X X

pH,DO,T  pH,DO  pH,D  pH,D  pH,DO,  pH,DO,Tubi  Turag ubidity,cl, ,Tubidi O,Tu O,Tu Tubidity dity,cl,NH4, NH4,PO  ty,cl,N  bidity  bidity  ,cl,NH4,  PO4  4,etc H4,PO ,cl,N ,cl,N PO4 4 H4,P H4,P O4 O4

Pb, Cd Pb, Cd,Cr, Cr, BOD BOD X BOD X BOD X BOD X BOD X X

pH,DO,T  pH,DO  pH,D  pH,D  pH,DO,  pH,DO,Tubi  Tongi Khal ubidity,cl, ,Tubidi O,Tu O,Tu Tubidity dity,cl,NH4, NH4,  ty,cl,N  bidity  bidity  ,cl,NH4,  PO4,etc  H4, ,cl,N ,cl,N PO4,etc PO4,etc H4, H4, PO4,et c PO4, PO4, etc etc

X X X X Pb, Cd, X Pb, Cd, X Cr,DO, Cr,DO, BOD BOD BOD BOD BOD BOD

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pH,DO,T  pH,DO  pH,D  pH,D  pH,DO,  pH,DO,Tubi  ubidity,cl, ,Tubidi O,Tu O,Tu Tubidity dity,cl,NH4, NH4,PO  ty,cl,N  bidity  bidity  ,cl,NH4,  PO4  Balu 4 H4,PO ,cl,N ,cl,N PO4 4 H4, H4

PO4 ,PO4

Cd, Cd, BOD,N BOD,NH4 BOD X BOD X BOD X BOD X H4 X X

pH,DO,T  pH,DO  pH,D  pH,D  pH,DO,  pH,DO,Tubi  Buriganga ubidity,cl, ,Tubidi O,Tu O,Tu Tubidity dity,cl,PO4 NH4,PO  ty,cl,N  bidity  bidity  ,cl,PO4   4 H4,PO ,cl,N ,cl,N 4 H4,P H4,P O4 O4

BOD X BOD X BOD X BOD X BOD,N X BOD,NH4 X H4

pH,DO,T  pH,DO  pH,D  pH,D  pH,DO,  pH,DO,Tubi  ubidity,cl, ,Tubidi O,Tu O,Tu Tubidity dity,cl,PO4 Sitalakhya NH4,PO  ty,cl,N  bidity  bidity  ,cl,PO4   4 H4, ,cl,N ,cl,N H4, H4, PO4 PO4 PO4

BOD X BOD X BOD X BOD X BOD X BOD X

pH,DO,T  pH,DO  pH,D  pH,D  pH,DO,  pH,DO,Tubi  Dhaleshwari ubidity,cl, ,Tubidi O,Tu O,Tu Tubidity dity,cl,NH4, NH4,PO  ty,cl,N  bidity  bidity  ,cl,NH4,  PO4  4 H4, ,cl,N ,cl,N PO4 H4, H4, PO4 PO4 PO4

pH,BOD,  pH,BO  pH,B  pH,B  pH,BO  pH,BOD,D  DO,Tubi D,DO, OD,D OD,D D,DO,T O,Tubidity,c dity,cl,N  Tubidit  O,Tu  O,Tu  ubidity,c  l,NH4,PO4  Padma H4,PO4, y,cl,N bidity bidity l,NH4, H4, ,cl,N ,cl,N etc etc H4, H4,P PO4,etc PO4,et O4, c PO4, etc etc

pH,BOD,  pH,BO  pH,B  pH,B  pH,BO  pH,BODDO  DO,Tubi D,DO, OD,D OD,D D,DO, ,Tubidity,cl,

dity,cl,N  Tubidit  O,Tu  O,Tu   NH4,PO4,  Meghna H4,PO4, y,cl,N bidity bidity Tubidity cl,NH4, H4,PO ,cl,N ,cl,N etc etc  4,etc H4, H4, PO4,etc

PO4, PO4,

etc etc

Note: X means not suitable,  means suitable

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It can be summarized that in dry season the quality of Balu, Buriganga, Turag and Tongi river are not suitable for use as source water for water treatment; whereas in wet season the quality becomes good to use by treatment arrangement. The quality of Sitalakhya, Dhaleswari , Padma and Meghna was found to be for use as source water for water treatment throughout the year. The pollution control measures need to be enforced to revive the Buriganga, Turag, Balu and Tongi rivers. Water of these rivers needs to be protected from all types of pollutions for the environmental safety and protection of water quality and public health.

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CHAPTER SIX

ANALYSIS OF SURFACE WATER AVAILABILITY

6.1 Introduction

One of the main objectives of this study is to assess suitable surface water sources to complement present water demand of Dhaka city. The analyses include both quantitative and qualitative assessments of water availability for two major river systems and the peripheral river systems around Dhaka city. The major rivers are Padma and Meghna and peripheral rivers are Buriganga, Balu, Turag, Tongi, Sitalakhya and Dhaleswari. Possible sources are analysed by measuring the mean annual flow, water level, flow exceedance curve, environmental flow and HEC RAS model. This chapter deals with the analysis of water quantity of the rivers Padma and Meghna and all peripheral rivers around Dhaka city to see the feasibility (from water quantity perspective) for future uses of these surface water sources for water supply for Dhaka city. Flow duration curve and model analysis would determine the year around water availability and also the dry season water availability. The major rivers have been discussed then the peripheral rivers have also been discussed in terms of mean annual flow, water level, environmental flow and model analyses was carried out after abstraction of water and see the impact on the network for surface water availability.

6.2 Description of Selected River Sources for Surface Water

The rivers network in Dhaka city is the main source of water which covers the Dhaka city from the outside boundary. The network includes Padma, Meghna and Jamuna as major rivers and Turag, Tongi khal, Balu, Buriganga, Sitalakhya and Dhaleswari are the peripheral rivers. These rivers are directly or indirectly linked as surface source to Dhaka city water supply. All these rivers may not contribute all together as surface water source but can affect each other. So a detail description has been given in subsequent sections to determine the potentials sources as future surface water sources.

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All the peripheral rivers are connected with large rivers and peripheral rivers receive water from large rivers. The hydraulic connection in relation to water supply of Dhaka city is shown in Figure 6.1:

Figure 6.1: Location of Rivers around Dhaka and their Hydraulic connection The distance of the major and peripheral rivers from Dhaka city is shown in Table 6.1. Table 6.1: Distance from Dhaka to all surrounding rivers

Name of Rivers Distance from Dhaka City (km) Remarks Padma 40.13 Meghna 33.5 Jamuna 98.8 Farthest away Balu 13.3 Tongi Khal 9.8 Turag 7.9 Shitalakya 13.9 Buriganga 10.3 Dhaleswari 21.9

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6.3 Peripheral Rivers and Major Rivers for Water Availability The peripheral rivers are the potential sources. These rivers are studied in details for water availability at first by flow hydrograph, exceedance probability curve and finally HEC RAS modelling. Water discharge, water level, flow velocity and the x-sec data are taken from BWDB and the study is carried out which are appended below in subsequent sections to determine the availability of surface water sources.

6.4 Monthly Average Flow and Water Level Hydrograph

For the assessment of surface water sources, historical time-series data of 10 years from 2006 to 2016 discharges were required. The total 08 rivers Balu, Turag, Tongi, Sitalakhya, Dhaleswari, Buriganga, Padma, Meghna were taken into consideration. The flow hydrograph of these eight rivers from January to December of 10 years were drawn. It was found that during dry season the water flow remains very low and during monsoon the flow remains substantial. In Figure 6.2 to 6.9 the graph showed the water flow revealed significant in wet season:

Turag River 500

400

300

200

Discharge(m3/s) 100

0 6-Jul 1-Jan 3-Jun 2-Oct 9-Apr 3-Feb 7-Dec 8-Aug 17-Jul 28-Jul 4-Nov 7-Mar 1-May 12-Jan 23-Jan 14-Jun 25-Jun 13-Oct 24-Oct 20-Apr 14-Feb 25-Feb 10-Sep 21-Sep 18-Dec 29-Dec 19-Aug 30-Aug 15-Nov 26-Nov 18-Mar 29-Mar 12-May 23-May Date

2006 2008 2010 2012 2014 2016

Figure 6.2: Flow Hydrographs of Turag River

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Tongi Khal 150

100

50 Discharge(m3/s)

0 9-Jul 1-Jan 9-Jun 7-Oct 7-Sep 6-Dec 8-Aug 19-Jul 29-Jul 6-Nov 1-Mar 11-Jan 21-Jan 31-Jan 19-Jun 29-Jun 17-Oct 27-Oct 10-Apr 20-Apr 30-Apr 10-Feb 20-Feb 17-Sep 27-Sep 16-Dec 26-Dec 18-Aug 28-Aug 16-Nov 26-Nov 11-Mar 21-Mar 31-Mar 10-May 20-May 30-May Date

2006 2008 2010 2012 2014 2016

Figure 6.3: Flow Hydrographs of Tongi Khal

Balu River 500 450

400 350 300 250 200 150

Discharge(m3/s) 100 50 0 9-Jul 1-Jan 9-Jun 7-Oct 7-Sep 6-Dec 8-Aug 19-Jul 29-Jul 6-Nov 1-Mar 11-Jan 21-Jan 31-Jan 19-Jun 29-Jun 17-Oct 27-Oct 10-Apr 20-Apr 30-Apr 10-Feb 20-Feb 17-Sep 27-Sep 16-Dec 26-Dec 18-Aug 28-Aug 16-Nov 26-Nov 11-Mar 21-Mar 31-Mar 10-May 20-May 30-May Date

2006 2008 2010 2012 2014 2016

Figure 6.4: Flow Hydrographs of Balu River

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Buriganga River 600

500

400

300

200

Discharge(m3/s) 100

2006 2008 2010 2012 2014 2016

Figure 6.5: Flow Hydrographs of Buriganga River

Sitalakhya River 800

700 600 500 400 300 200

Discharge(m3/sec) 100 0 1-Jan 5-Jun 3-Oct 6-Apr 6-Feb 9-Sep 2-Dec 4-Aug 11-Jul 23-Jul 8-Nov 1-Mar 13-Jan 25-Jan 17-Jun 29-Jun 15-Oct 27-Oct 18-Apr 30-Apr 18-Feb 21-Sep 14-Dec 26-Dec 16-Aug 28-Aug 20-Nov 13-Mar 25-Mar 12-May 24-May Date

2006 2008 2010 2012 2014 2016

Figure 6.6: Flow Hydrograph of Sitalakhaya River

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Dhaleshwari River 1500 1300 1100 900 700 500

Discharge(m3/s) 300 100 -100 6-Jul 1-Jan 3-Jun 2-Oct 9-Apr 3-Feb 7-Dec 8-Aug 17-Jul 28-Jul 4-Nov 7-Mar 1-May 12-Jan 23-Jan 14-Jun 25-Jun 13-Oct 24-Oct 20-Apr 14-Feb 25-Feb 10-Sep 21-Sep 18-Dec 29-Dec 19-Aug 30-Aug 15-Nov 26-Nov 18-Mar 29-Mar 12-May 23-May Date

2006 2008 2010 2012 2014 2016

Figure 6.7: Flow Hydrographs of Dhaleshwari River

Padma River 70000

60000

50000

40000

30000

Discharge(m3/s) 20000

10000

2006 2008 2010 2012 2014 2016

Figure 6.8: Flow Hydrographs of Padma River

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Meghna River 11000 10000

9000 8000 7000 6000 5000 4000 3000 Discharge(m3/s) 2000 1000 0 9-Jul 1-Jan 9-Jun 7-Oct 7-Sep 6-Dec 8-Aug 19-Jul 29-Jul 6-Nov 1-Mar 11-Jan 21-Jan 31-Jan 19-Jun 29-Jun 17-Oct 27-Oct 10-Apr 20-Apr 30-Apr 10-Feb 20-Feb 17-Sep 27-Sep 16-Dec 26-Dec 18-Aug 28-Aug 16-Nov 26-Nov 11-Mar 21-Mar 31-Mar 10-May 20-May 30-May Date

2006 2008 2010 2012 2016

Figure 6.9: Flow Hydrographs of Meghna River

Historical time-series data of 10 years from 2006 to 2016 water level was taken to construct water level hydrograph. The total 06 rivers Balu, Turag, Tongi, Sitalakhya, Dhaleswari and Buriganga were taken into devotion. The flow hydrograph of these six rivers from January to December of 10 years were measured. It was established that during dry season the water flow remains very low and during monsoon the flow remains substantial. In Figure 6.10 to 6.17 the graph showed the water flow exposed significant in wet season:

Turag Rivers 6 5

) 4 3

mPWD 2 1 0 Water Level ( Level Water 6-Jul 1-Jan 3-Jun 2-Oct 9-Apr 3-Feb 7-Dec 8-Aug 17-Jul 28-Jul 4-Nov 7-Mar 1-May 12-Jan 23-Jan 14-Jun 25-Jun 13-Oct 24-Oct 20-Apr 14-Feb 25-Feb 10-Sep 21-Sep 18-Dec 29-Dec 19-Aug 30-Aug 15-Nov 26-Nov 18-Mar 29-Mar 12-May 23-May Date

2006 2008 2010 2012 2014 2016

Figure 6.10: Water Level Hydrographs of Turag River 117

Tongi Khal 6

Water Level (mPWD) Level Water 1

2006 2008 2010 2012 2014 2016

Figure 6.11: Water Level Hydrographs of Tongi Khal

Balu River 6

Water Level (mPWD) Level Water 1

2006 2008 2010 2012 2014 2016

Figure 6.12: Water Level Hydrographs of Balu River

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Buriganga River 6

Water Level (mPWD) Level Water 1

2006 2008 2010 2012 2014 2016

Figure 6.13: Water Level Hydrographs of Buriganga River

Sitalakhya River 7

Water Level (mPWD) Level Water 1

Figure 6.14: Water Level Hydrographs of Sitalakhya River

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Dhaleswari River 8

2 Water Level (mPWD) Level Water 1

2008 2010 2012 2014 2016

Figure 6.15: Water Level Hydrographs of Dhaleswari River

Padma River 9

8 7 6 5 4 3 2

Water Level (mPWD) Level Water 1 0 9-Jul 1-Jan 9-Jun 7-Oct 7-Sep 6-Dec 8-Aug 19-Jul 29-Jul 6-Nov 1-Mar 11-Jan 21-Jan 31-Jan 19-Jun 29-Jun 17-Oct 27-Oct 10-Apr 20-Apr 30-Apr 10-Feb 20-Feb 17-Sep 27-Sep 16-Dec 26-Dec 18-Aug 28-Aug 16-Nov 26-Nov 11-Mar 21-Mar 31-Mar 10-May 20-May 30-May Date

2006 2008 2010 2012 2014 2016

Figure 6.16: Water Level Hydrographs of Padma River

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Meghna Rivers 9

Water Level (mPWD) Level Water 2

2006 2008 2010 2012 2014 2016

Figure 6.17: Water Level Hydrographs of Meghna River

In above graphs it was found that water remains a lesser amount for specially for Tongi and Turag river from November to May in comparison to June to October. The water flow and water level remains noteworthy for Buriganga, Balu, Sitalakhya and Dhaleswari rivres. Monthly mean flow of all rivers has been calculated as shown in Table 6.2 by averaging the monthly flow data of 10 years period. Table 6.2: Monthly Mean flow for all the peripheral rivers in m3/s River Station ID/Name Jan Feb Mar Apr May Jun

Turag SW 302/Mirpur 18.38 15.95 17.38 32.95 63.12 76.31 Tongi Khal SW 299/Tongi 1.11 1.79 1.61 3.01 4.09 9.97 Balu SW 7.5/Demra 17.51 16.52 15.87 17.21 28.32 127.93 Buriganga SW 42/Mill Barrack 18.41 19.39 26.12 26.55 33.69 188.39 Sitalakhya SW 179/Demra 26.63 32.11 38.53 48.68 72.90 270.60 Dhaleshwari SW 71/Jagir 110.97 115.40 117.39 118.23 160.79 434.77 Padma SW 93.5/Mawa 6909.85 5924.06 6911.42 8552.16 15980.26 47812.14 Meghna SW273/Bhairab Bazar 583.84 1384.43 1520.55 1924.80 3058.23 9965.91

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Contd. River Station ID/Name July Aug Sep Oct Nov Dec Turag SW 302/Mirpur 212.75 386.46 352.42 193.92 39.46 26.70 Tongi Khal SW 299/Tongi 18.39 50.33 73.35 61.36 11.22 2.73 Balu SW 7.5/Demra 398.93 354.40 290.31 284.54 44.61 18.65 Buriganga SW 42/Mill Barrack 398.41 462.31 439.84 367.80 69.12 30.88 Sitalakhya SW 179/Demra 285.85 506.00 577.22 691.88 360.38 32.83 Dhaleshwari SW 71/Jagir 665.69 1071.09 1219.09 1010.96 363.28 79.63 Padma SW 93.5/Mawa 46408.55 59707.77 39928.77 28202.23 14552.32 7490.65 Meghna SW273/Bhairab Bazar 9139.79 9874.59 8669.14 8712.57 7960.50 5691.70

From the Table 6.2, it can be seen that the water flow in dry season is reduced compared to wet season specially for Tongi, Turag and Balu rivers. The peripheral rivers and all other major rivers have sufficient flow that can be used as source of surface water for Dhaka city. In the following sections, the estimation of environmental flows required for the survival of the peripheral rivers has been discussed.

6.5 Environmental Flow Estimation The 10% flow requirement for a watercourse is expressed as a percentage of the mean annual naturalized flow at a specified site. The naturalized flow regime is the hydrological regime of the watercourse with the man-made influences (e.g. abstractions of water, changes in runoff resulting from urbanization) removed from the flow. To produce a naturalized flow series flow records are required. In Table 6.3 the 10% mean annual flow is shown for the assessment of environmental flow of all eight rivers under consideration:

6.5.1 Assessment of 10% Mean Annual Flow (MAF) The most advantage of this method is that it is simple to use. Once relationships between discharge and the river environment have been established it requires relatively few sets of data and it does not require exorbitant fieldwork to be carried out. In addition, it does not preserve the natural variability of the watercourse by taking account of daily and yearly variation of flows i.e. the method only prescribes a minimum environmental base flow. The natural flow i.e. the regime before any anthropogenic influences on the watercourse have occurred has to be established. The method does not produce a zero flow recommendation.

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Table 6.3: Environmental Flow Requirement using 10% MAF Method River Name Station Annual Total Mean Annual 10% MAF ID/Name Flow (m3/s) Flow (m3/s) (m3/s) Turag SW 302/Mirpur 1444.09 120.34 12.03 Tongi Khal SW 299/Tongi 149.26 12.44 1.24 Balu SW 7.5/Demra 1614.89 134.57 13.46 Buriganga SW 42/Dhaka_Mill Barrack 2080.90 173.41 17.34 Sitalakhya SW 179/Demra 3025.75 252.15 25.21 Dhaleshwari SW 71/Jagir 8195.61 682.97 68.30 Padma SW 93.5/Mawa 289348.17 24112.35 2411.23 Meghna SW 273/Bhairab Bazar 74026.82 6168.90 616.89

In Table 6.3 it is evident that minimum flow occurs for Tongi khal and Turag river where as the other rivers relatively higher amount environmental flow.

6.5.2 Estimation from Flow Duration curve in terms of Q90 and Q50 Assessment of the 50th and 90th percentile flows can be calculated from flow duration curve. Flow duration curve in a river can be analysed in terms of flow of river and its expected duration of availability. Such curves are useful in appraising the characteristics of a river basin. Flow duration curves for each month for the period (2006-2016) have been constructed from daily mean discharge. The recommended flow for e-flow is set at 90th percentile for normal months and 50th percentile for high flow months. Therefore, Q90 and Q50 of all peripheral and major rivers were calculated from flow-duration curves for two time periods as shown in Figure 6.18 to 6.25.

Flow Data - Turag River SW 302/Mirpur(2006-2016) 450.0

400.0 350.0

) 300.0 250.0 m3/sec 200.0 150.0

100.0

Flow Data ( Data Flow 50.0

0.0

0 20 40 60 80 100 % Of time flow equalled or exceeded

Figure 6.18: Flow Duration Curve of Turag River

123

Flow Data - Tongi Khal SW 299/Tongi (2006-2016) 60.0

50.0

) 40.0 m3/s

30.0

Flow Data ( Data Flow 20.0

10.0

0.0 0 20 40 60 80 100 % Of time flow equalled or exceeded

Figure 6.19: Flow Duration Curve of Tongi River

Flow Data - Balu River SW 7.5/Demra (2006-2016) 450.0 400.0

350.0 ) 300.0 m3/s 250.0 200.0

Flow Data ( Data Flow 150.0 100.0 50.0 0.0 0 20 40 60 80 100 % Of time flow equalled or exceeded

Figure 6.20: Flow Duration Curve of Balu River

124

Flow Data - Buriganga River SW 42/Dhaka (2006-2016) 600.0

500.0

) 400.0 m3/s

300.0

Flow Data ( Data Flow 200.0

100.0

0.0 0 20 40 60 80 100 % Of time flow equalled or exceeded

Figure 6.21: Flow Duration Curve of Buriganga River

Flow Data - Shitakakhya SW 179/Demra (2006-2016) 800.0

700.0

) 600.0

m3/s 500.0

400.0

300.0 Flow Data ( Data Flow

200.0

100.0

0.0 0 20 40 60 80 100 % Of time flow equalled or exceeded

Figure 6.22: Flow Duration Curve of Sitalakhaya River

125

Flow Data - Daleshwari River SW 71 (2006-2016) 2500.0

2000.0

)

1500.0

1000.0

(m3/s Data Flow

500.0

0.0 0 20 40 60 80 100 % Of time flow equalled or exceeded

Figure 6.23: Flow Duration Curve of Daleshwari River

Flow Data - Padma River SW 93.5/Mawa (2006-2016) 80000.0

70000.0

60000.0

50000.0

40000.0

30000.0 Flow Data (m3/s) Data Flow 20000.0

10000.0

0.0 0 20 40 60 80 100 % Of time flow equalled or exceeded

Figure 6.24: Flow Duration Curve of Padma River

126

Flow Data - Meghna SW 273/Bhairab Bazar (2006-2016) 12000.0

10000.0

) 8000.0 m3/s

6000.0

Flow Data ( Data Flow 4000.0

2000.0

0.0 0 20 40 60 80 100 % Of time flow equalled or exceeded

Figure 6.25: Flow Duration Curve of Meghna River

Considering May to October as high flow months Q50 and November to April as normal months Q90 was considered for the e-flow for peripheral and large rivers as shown in Table 6.4.

Table 6.4: Flow Q90 and Q50 for the selected rivers River Name Station ID/Name Nov-Apr May - Oct 3 3 Flow Q90 m /sec Flow Q50 m /sec Turag SW 302/Mirpur 16.00 49.50 Tongi Khal SW 299/Tongi 2.00 9.00 Balu SW 7.5/Demra 16.50 67.30 Buriganga SW 42/Dhaka_Mill Barrack 17.00 92.00 Sitalakhya SW 179/Demra 27.00 141.00 Dhaleshwari SW 71/Jagir 90.00 169.00 Padma SW 93.5/Mawa 6779.00 14615.00 Meghna SW 273/Bhairab Bazar 937.00 7954.00

6.6 Suitability of River Data

The water quality of per ipheral rivers around Dhaka city was analysed in details in Chapter 5 with respect to pH, turbidity, dissolved oxygen (DO), biochemical ox ygen demand (BOD), chemical oxygen demand (COD), ammonium (NH4+), nitrate (NO3), phosphate(PO4 3-), chromium (Cr), mercury (Hg), lead (Pb), Zinc (Zn). Analysis of water quality in the river system in dry period from November to April reveals that river water quality deteriorates from January, reaches the worst

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condition in April ; actually from November to April the water quality remains very poor in Buriganga, Balu, Turag and Tongi. The quality of other peripheral rivers remains good to be used as source water for water treatment. Table 6.5 shows suitability of rivers on a monthly basis as source water for water treatment. The suitability of water for domestic use is compared with the standard criteria as set by ECR (1997). Table 6.5: Water Quality of Peripheral and Major Rivers (Conferred from Chapter 5) River Name Suitability of Water Jan Feb Mar Apr May Jun July Aug Sep Oct Nov Dec Turag X X X X       X X Tongi Khal X X X X       X X Balu X X X X       X X Buriganga X X X X       X X Shitalakhya             Dhaleshwari             Padma             Meghna            

Note: means suitable and x means not suitable

Table 6.5: Water Quality of Peripheral and Major Rivers (Conferred from Chapter 5) River Name Suitability of Water Jan Feb Mar Apr May Jun July Aug Sep Oct Nov Dec Turag X X X X       X X Tongi Khal X X X X       X X Balu X X X X       X X Buriganga X X X X       X X Sitalakhya             Dhaleshwari             Padma             Meghna            

Note: means suitable and X means not suitable

6.7 Navigability To assess the navigability, the waterways are classified in different categories as per BIWTA (1989) classification of IWT routes. The inland waterway routes of Bangladesh have been classified into four types depending on least available depth (LAD). The classification can be seen in Table 6.6.

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Table 6.6: Classification of IWT Route according to BIWTA

IWT Route LAD (m) Selected Rivers under the IWT classification Class- I 3.60-3.66 Padma Class- II 2.10-2.46 Meghna Class -III 1.50-1.8 Balu, Buriganga, Sitalakhya, Dhaleswari, Turag and Tongi khal Class -IV Less than 1.50 m

It is evident from the results that in dry season it is difficult to maintain navigability as the LAD falls below 1.5 m. However, circular waterways become navigable in wet season as these are satisfying the criteria of class II and class III routes. The available navigable depths of all rivers in different months and its navigability for class three type routes are shown in Table 6.7. In addition Figure 6.26 also shows the available depths for navigation for the peripheral rivers.

Table 6.7 : Available Depths, Water level and Navigability of Peripheral Rivers January February March

River Name ed ed ed (mPWD) (mPWD) (mPWD) B B B

WL WL . . . igability

evel evel evel Avg Avg WL (mPWD) Min L Depth (m) Nav Avg (mPWD) Min L Depth (m) Navigability Avg WL (mPWD) Min L Depth (m) Navigability Turag 1.36 -0.15 1.51 x 1.35 -0.15 1.50 x 2.34 -0.15 2.49 √ Tongi Khal 1.35 -0.10 1.45 x 1.41 -0.10 1.51 x 2.30 -0.10 2.40 √ Balu 2.05 -1.25 3.30 √ 1.84 -1.25 3.09 √ 3.41 -1.25 4.66 √ Buriganga 1.98 -3.90 5.88 √ 2.91 -3.90 6.81 √ 3.29 -3.90 7.19 √ Sitalakhya 2.00 -5.20 7.20 √ 2.98 -5.20 8.18 √ 3.11 -5.20 8.31 √ Dhaleshwari 2.07 -9.00 11.07 √ 2.94 -9.00 11.94 √ 3.41 -9.00 12.41 √ Padma 2.15 -20.00 22.15 √ 2.89 -20.00 22.89 √ 2.70 -20.00 22.70 √ Meghna 2.31 -15.00 17.31 √ 2.54 -15.00 17.54 √ 2.99 -15.00 17.99 √

Table 6.7 Contd.

April May June

River Name ed ed ed (mPWD) (mPWD) (mPWD)

evel evel evel Avg Avg WL (mPWD) Min B L Depth (m) Navigability Avg WL (mPWD) Min B L Depth (m) Navigability Avg WL (mPWD) Min B L Depth (m) Navigability Turag 2.71 -0.15 2.86 √ 3.45 -0.15 3.60 √ 3.21 -0.15 3.36 √ Tongi Khal 2.94 -0.10 3.04 √ 3.34 -0.10 3.44 √ 3.55 -0.10 3.65 √ Balu 3.66 -1.25 4.91 √ 3.42 -1.25 4.67 √ 3.61 -1.25 4.86 √ Buriganga 3.59 -3.90 7.49 √ 3.39 -3.90 7.29 √ 4.74 -3.90 8.64 √ Sitalakhya 3.97 -5.20 9.17 √ 3.29 -5.20 8.49 √ 4.57 -5.20 9.77 √ 129

Dhaleshwari 3.82 -9.00 12.82 √ 3.37 -9.00 12.37 √ 4.73 -9.00 13.73 √ Padma 3.38 -20.00 23.38 √ 3.17 -20.00 23.17 √ 6.03 -20.00 26.03 √ Meghna 3.13 -15.00 18.13 √ 3.21 -15.00 18.21 √ 6.59 -15.00 21.59 √

Table 6.7 Contd…

July August September

River Name ed ed ed (mPWD) (mPWD) (mPWD)

evel Avg Avg WL (mPWD) Min B L Depth (m) Navigability Avg WL (mPWD) Min B Level Depth (m) Navigability Avg WL (mPWD) Min B Level Depth (m) Navigability Turag 4.81 -0.15 4.96 √ 5.55 -0.15 5.70 √ 3.78 -0.15 3.93 √ Tongi Khal 2.99 -0.10 3.09 √ 4.79 -0.10 4.89 √ 4.81 -0.10 4.91 √ Balu 3.37 -1.25 4.62 √ 4.17 -1.25 5.42 √ 4.60 -1.25 5.85 √ Buriganga 5.42 -3.90 9.32 √ 5.27 -3.90 9.17 √ 5.62 -3.90 9.52 √ Sitalakhya 6.07 -5.20 11.27 √ 5.84 -5.20 11.04 √ 6.54 -5.20 11.74 √ Dhaleshwari 7.14 -9.00 16.08 √ 5.85 -9.00 14.85 √ 5.39 -9.00 14.39 √ Padma 7.14 -20.00 27.14 √ 8.32 -20.00 28.32 √ 7.42 -20.00 27.42 √ Meghna 6.01 -15.00 21.01 √ 7.71 -15.00 22.71 √ 6.55 -15.00 21.55 √

Table 6.7 Contd… October November December

River Name ed ed ed

(mPWD) mPWD) Avg Avg WL (mPWD) Min B Level (mPWD) Depth (m) Navigability Avg WL (mPWD) Min B level Depth (m) Navigability Avg WL (mPWD) Min B Level ( Depth (m) Navigability

Turag 3.20 -0.15 3.35 √ 2.50 -0.15 2.65 √ 1.09 -0.15 1.24 X Tongi Khal 3.08 -0.10 3.18 √ 1.69 -0.10 1.79 √ 1.41 -0.10 1.51 X Balu 4.64 -1.25 5.89 √ 3.75 -1.25 5.00 √ 2.72 -1.25 3.97 √ Buriganga 4.81 -3.90 8.71 √ 3.51 -3.90 7.41 √ 2.75 -3.90 6.65 √ Sitalakhya 4.74 -5.20 9.94 √ 3.71 -5.20 8.91 √ 2.67 -5.20 7.87 √ Dhaleshwari 4.25 -9.00 13.25 √ 3.61 -9.00 12.61 √ 3.51 -9.00 12.51 √ Padma 5.86 -20.00 25.86 √ 3.59 -20.00 23.59 √ 3.14 -20.00 23.14 √ Meghna 3.63 -15.00 18.63 √ 2.98 -15.00 17.98 √ 2.80 -15.00 17.80 √

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Available Depths of Peripheral Rivers 16 Tongi Turag Balu Buriganga Dhaleswari Shitalakhya 14 12

10 8

Depths(m) 6 4 2 0 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec12 Month

Figure 6.26: Available Depths of Peripheral Rivers

6.8 Water Availability of Surface Water Sources

In the Table 6.7, different calculations of ten years 2006 to 2016 have been shown regarding monthly average flow (Qavg), environmental flow and navigability. After assessment of water quality parameter in previous chapter (Table 5.23) the availability of surface water was determined. Table 6.8 shows the calculations for all rivers on monthly basis. Table 6.8 : Availability of Surface Water

Station Q(m3/s), River Name Jan Feb Mar Apr May June ID/Name LAD(m) SW 302/Mirpur Qavg 18.38 17.38 17.38 32.95 63.12 74.65 SW 302/Mirpur Qenv 16.00 16.00 16.00 16.00 49.50 49.50

Turag SW 302/Mirpur Nav.(m)>LAD X X    

SW 302/Mirpur Quality X X X X   SW 302/Mirpur Availability 0.00 0.00 0.00 0.00 13.62 25.15 SW 299/Tongi Qavg 1.10 1.67 2.59 2.86 4.39 11.08 SW 299/Tongi Qenv 1.88 1.88 1.88 1.88 9.00 9.00

Tongi Khal SW 299/Tongi Nav.(m)>LAD X X     SW 299/Tongi Quality X X X X   SW 299/Tongi Availability 0.00 0.00 0.00 0.00 -4.61 2.08 SW 7.5/Demra Qavg 17.51 16.46 17.36 17.36 127.93 127.93 SW 7.5/Demra Qenv 16.50 16.50 16.50 16.50 67.30 67.30 Balu SW 7.5/Demra Nav.(m)>LAD      

SW 7.5/Demra Quality X X X X  

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SW 7.5/Demra Availability 0.00 0.00 0.00 0.00 60.63 60.63 SW 42/Mill Barrack Qavg 18.41 19.39 26.12 26.55 33.69 188.39 SW 42/Mill Barrack Qenv 17.34 17.34 17.34 17.34 92.00 92.00 Buriganga SW 42/Mill Barrack Nav.(m)>LAD      

SW 42/Mill Barrack Quality X X X X   SW 42/Mill Barrack Availability 0.00 0.00 0.00 0.00 -58.31 96.39 SW 179/Demra Qavg 26.63 32.11 38.53 48.68 155.04 270.60 SW 179/Demra Qenv 27.00 27.00 27.00 27.00 141.00 141.00 Sitalakhya SW 179/Demra Nav.(m)>LAD       SW 179/Demra Quality       SW 179/Demra Availability 0.00 5.11 11.53 21.68 14.04 129.60 SW 71/Jagir Qavg 103.02 116.08 132.63 150.72 216.36 666.97 SW 71/Jagir Qenv 90 90 90 90 169.00 169.00 Dhaleshwari SW 71/Jagir Nav.(m)>LAD       SW 71/Jagir Quality       SW 71/Jagir Availability 13.02 26.08 42.63 60.72 47.36 497.97 SW 93.5/Mawa Qavg 6909.85 6884.50 6911.42 8559.71 15980.26 47812.14 SW 93.5/Mawa Qenv 6750.00 6750.00 6750.00 6750.00 14615.00 14615.00 Padma SW 93.5/Mawa Nav.(m)>LAD       SW 93.5/Mawa Quality       SW 93.5/Mawa Availability 159.85 134.50 161.42 1809.71 1365.26 33197.14 SW 273/Bhairab Qavg 945.08 1384.43 1520.55 1924.80 8237.77 9965.91 SW 273/Bhairab Qenv 937.00 937.00 937.00 937.00 7954.00 7954.00 Meghna SW 273/Bhairab Nav.(m)>LAD       SW 273/Bhairab Quality       SW 273/Bhairab Availability 8.08 447.43 583.55 987.80 283.77 2011.91 Total Availability Excluding Padma & Meghna 13.02 31.19 64.17 82.41 72.73 811.81 Total Availability 180.59 613.11 799.14 2979.91 1721.76 36020.86

Contd… Station Q (m3/s) River Name July Aug Sep Oct Nov Dec ID/Name SW 302/Mirpur Qavg 208.93 391.74 353.48 201.36 39.46 26.70 SW 302/Mirpur Qenv 49.50 49.50 49.50 49.50 16.00 16.00

Turag SW 302/Mirpur Nav.(m)>LAD      X X SW 302/Mirpur Quality     X X SW 302/Mirpur Availability 159.43 342.24 303.98 151.86 0.00 0.00 SW 299/Tongi Qavg 16.38 21.15 27.60 43.14 11.78 5.51 SW 299/Tongi Qenv 9.00 9.00 9.00 9.00 1.88 1.88 Tongi Khal SW 299/Tong Nav.(m)>LAD      X X SW 299/Tongi Quality     X X

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SW 299/Tongi Availability 7.38 12.15 18.60 34.14 0.00 0.00 SW 7.5/Demra Qavg 398.93 354.40 290.31 284.54 44.61 18.65 SW 7.5/Demra Qenv 67.30 67.30 67.30 67.30 16.50 16.50

Balu SW 7.5/Demra Quality     X X SW 7.5/Demra Nav.(m)>LAD       SW 7.5/Demra Availability 331.63 287.10 223.01 217.24 0.00 0.00 SW42/Mill Barrack Qavg 398.41 462.31 439.84 367.80 69.12 30.88 SW42/Mill Barrack Qenv 92.00 92.00 92.00 92.00 17.34 17.34

Buriganga SW42/Mill Barrack Quality     X X SW42/Mill Barrack Nav.(m)>LAD       SW42/Mill Barrack Availability 306.41 370.31 347.84 275.80 0.00 0.00 SW 179/Demra Qavg 285.85 506.00 577.22 691.88 360.38 32.83 SW 179/Demra Qenv 141.00 141.00 141.00 141.00 27.00 27.00 Sitalakhya SW 179/Demra Nav.(m)>LAD       SW 179/Demra Quality       SW 179/Demra Availability 144.85 365.00 436.22 550.88 333.38 5.83 SW 71/Jagir Qavg 1424.92 1847.86 1693.90 1235.07 478.67 129.42 SW 71/Jagir Qenv 169.00 169.00 169.00 169.00 90 90 Dhaleshwari SW 71/Jagir Nav.(m)>LAD       SW 71/Jagir Quality       SW 71/Jagir Availability 1255.92 1678.86 1524.90 1066.07 388.67 39.42 SW 93.5/Mawa Qavg 46408.55 59707.77 39928.77 28202.23 14552.32 7490.65 SW 93.5/Mawa Qenv 14615.00 14615.00 14615.00 14615.00 6750.00 6750.00 Padma SW 93.5/Mawa       SW 93.5/Mawa Quality       SW 93.5/Mawa Availability 31793.55 45092.77 25313.77 13587.23 7802.32 740.65 SW 273/Bhairab Qavg 9139.79 9874.59 8669.14 8712.57 7960.50 5691.70 SW 273/Bhairab Qenv 7954.00 7954.00 7954.00 7954.00 918.00 918.00 Meghna SW 273/Bhairab Nav.(m)>LAD       SW 273/Bhairab Quality       SW 273/Bhairab Availability 1185.79 1920.59 715.14 758.57 7042.50 4773.70 Total Availability Excluding Padma & Meghna 2205.62 3055.64 2854.53 2296.00 722.05 55.25 Total Availability 35184.96 50069.00 28883.44 16641.80 15576.88 5569.59

In the above findings, it was marked that minimum flow combining all peripheral rivers excluding Padma and Meghna was found 13.02 m3/s in January, which is not enough to meet the requirement for Dhaka city. Considering all the parameters (environmental flow, quality etc) other months hold sufficient water which is more than 30 m3/s to provide supply for surface water. If Padma and Meghna can be added with peripheral rivers, these will be complementary sources for Dhaka city water supply. Therefore, it is important to note that, if there is minimum or less pollution 133

in peripheral rivers around Dhaka city, the supply would be mammoth for Dhaka city water supply. The pressure would be decreased for ground water and maximum environmental benefit would be achieved for Dhaka city dwellers.

6.9 Effect of Water Withdrawal using HEC-RAS 1D Model 6.9.1 Hydrodynamic Model Results and Analysis

Hydrodynamic model consists of seven imporatant rivers named as Balu, Sitalakhya, Turag, Karnatali Buriganga,tongi khal and Dhaleshwari which cover the regions of dhaka metropolitan area including uttara, Gazipur, Kaliganj, Rupganj, Savar, Pallabi, Mirpur, Demra, Badda, Mohammadpur, Dhanmondi, Keranigang Gulshan, Tejgaon, Kafrul and so on. In this section a hydrodynamic modelling of the Dhaka peripheral river system has been develped to assess the available water in the thana and unions of Dhaka city. For detailed analysis of these rivers (river discharge, flow velocity, cross sectional properties, variations of water depth at different portion of the river) it is necessary to prepare a hydrodynamic model (HD model) for the river system. From a properly calibrated and validated hydrodynamic model, one can easily analyze those river segment properties both spatially and temporally. In the following sections of this chapter, development of HD model for all the peripheral river system has been described in order to assess the available water level, depth and velocity in different selected intake locations of the rivers. After establishing the river systems, all surveyed and obtained cross-sections were incorporated. Other essential model parameters especially Manning’s n were assigned for all reaches and chainages with reasonable roughness values. It is noted here that the coefficient of roughness estimates are being updated in the calibration process. The input data for four discharge locations and one stage location for Balu, Sitalakhya, Turag, Balu and Dhaleseari rivers have been given in the model. The model boundary locations are shown in Figure 6.27. The boundary data for each location are shown in Figures 6.28 to 6.32.

134

Map Showing the Boundary Locations

Figure 6.27: HEC RAS Model Boundary Locations

135

Plan: Base Flow River: Balu Reach: 111 RS: 11105 1000 Legend

Flow

800

600 Flow (m3/s) Flow

400

200

0 Feb Apr Jun Aug Oct Dec Feb 2014 2015 Time Figure 6.28: Boundary discharge (Q) data of Balu river

Plan: Base Flow River: Lakhya Reach: 261 RS: 26101 1400 Legend

Flow

1200

1000

800

600

Flow (m3/s) Flow 400

200

-200

-400 Feb Apr Jun Aug Oct Dec Feb 2014 2015 Time Figure 6.29: Boundary Discharge (Q) data of Lakhya River

136

Plan: Base Flow River: Turag Reach: 331 RS: 33101 600 Legend

Flow

500

400

300 Flow (m3/s) Flow 200

100

-100 Feb Apr Jun Aug Oct Dec Feb 2014 2015 Time Figure 6.30: Boundary Discharge (Q) data of Turag River

Plan: Base Flow River: Dhaleshwari Reach: last_reach RS: 18096 8000 Legend

Flow

6000

4000 Flow (m3/s) Flow

2000

-2000 Feb Apr Jun Aug Oct Dec Feb 2014 2015 Time Figure 6.31: Boundary Discharge (Q) data of Dhaleswari River

137

Plan: Base Flow River: Dhaleshwari Reach: last_reach RS: 18096 7 Legend

Stage 6

4 Stage (m) Stage

1 Feb Apr Jun Aug Oct Dec Feb 2014 2015 Time Figure 6.32: Boundary Water level (WL) data of Dhaleswari River

6.9.2 Model Setup

The model set up was required to carry out base and withdrawal scenario analysis. To analysis the water availability of Dhaka city, the hydrodynamic model set up consists of all the peripheral rivers namely the Balu, Sitalakhya, Turag, Tongi khal, Karnatali, Buriganga and Dhaleshwari has been developed and simulated. First of all the bathymetry data is used to prepare a schematic plot of river networks consisting of the connectivity of the river system, cross-section data and the junction information. In this analysis, bathymetry of the peripheral river network of Dhaka city has been prepared by drawing a 25 km reach of Balu river consisting of 22 cross sections, 65 km reach of Sitalakhya river having 18 cross sections, 36 km reach of Turag river with 25 cross sections, 26 km reach of Buriganga river having 13 cross sections, 16 km reach of Tongi khal having 12 cross sections, 50 km reach of Dhaleshwari with 26 cross sections and 5 junctions. Information of the river reach is given by inputting all the cross-sectional data, defining main channel bank stations and left and right overbanks for the year 2014. In chapter 4, the Hydrodynamic model has been discoursed and the output of the model in different scenario has been described in subsequent articles of this

138

chapter. For a hydrodynamic model, it is often a challenge to fix the value of Manning’s n. For present study the Manning’s n for channel is determined during calibration of model with existing geometry. The HEC-RAS model set up is shown in Figure 6.33:

Figure 6.33: Hydrodynamic Model Set up of River network

6.9.3 Calibration and Validation of the Hydrodynamic Model:

Model reliability depends upon its calibration and validation of results as it is one of very important step before put the model in use. In this study calibration has been done through the adjustment of Manning’s roughness coefficients. Manning’s n is the key tuning parameter of the 1-D HEC-RAS model whose appropriate value is very significant for accuracy depending on the factors like surface roughness, vegetation cover or land use ,channel irregularities etc. For hydrodynamic calibration of the model simulated stage hydrograph has been compared with observed stage hydrograph of all rivers. Manning’s roughness coefficient has been adjusted and after several trial, average value of n = 0.025 showed better match of the simulated and observed water levels. Figure 6.34 shows the water level calibration result of Turag river which is done for the year 2014. Then the model outputs 139

have been checked to assure that it performs satisfactorily. The model was validated for the period of the year 2015 that shows a good agreement with the observed data as shown in Figure 6.35. The results in the graphs indicate that the model predicts the water level satisfactorily for most of the discharge values in hydrographs. Figure 6.30 showed the result of validation for Turag river. For the other rivers in the model network, the calibration and validation are shown in Figures 6.34 to 6.45.

Observed and Simulated Water Level in Turag River 8

4 Simulated 3 Observed

Water Level (mPWD 2

0 21-May 10-Jun 30-Jun 20-Jul 9-Aug 29-Aug 18-Sep 8-Oct Date

Figure 6.34: Calibration of the numerical model of Turag River in Year 2014

Observed and Simulated Water Level in Turag River 8

6 )

4 Simulated

3 Observed

Water Level (mPWD 2

0 16/May 5/Jun 25/Jun 15/Jul 4/Aug 24/Aug 13/Sep 3/Oct 23/Oct Date

Figure 6.35 : Validation of the numerical model of Turag River in Year 2015

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Model reliability depends upon its calibration and validation of results as important steps before put the model in use. In this model, this has been done through the adjustment of Manning’s roughness coefficients. For calibrating this model simulated stage hydrographs are compared with observed stage hydrograph the period of calibration in 2014 for Manning’s n value 0.015 to 0.045 and validated with data of 2015 for all peripheral rivers and found satisfactory.

Observed and Simulated Water Level in Tongi Khal 8 7

) 6 5

4 Simulated 3 Observed 2 Water Level (mPWD 1 0 10-Jun 30-Jun 20-Jul 9-Aug 29-Aug 18-Sep 8-Oct 28-Oct 17-Nov Date Figure 6.36 : Calibration of the numerical model of Tongi Khal in Year 2014

Observed and Simulated Water Level in Tongi Khal 7

) 5

3 Simulated Observed 2 Water Level (mPWD 1

0 6/5/2015 6/25/2015 7/15/2015 8/4/2015 8/24/2015 9/13/2015 10/3/201510/23/201511/12/2015 Date

Figure 6.37 : Validation of the numerical model of Tongi Khal in Year 2015

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Observed and Simulated Water Level in Balu River 5 4.5 4

) 3.5 3 2.5 Simulated 2 Observed 1.5 Water Level (mPWD 1 0.5 0 12-Dec 1-Jan 21-Jan 10-Feb 2-Mar 22-Mar 11-Apr 1-May 21-May 10-Jun Date

Figure 6.38 : Calibration of the numerical model of Balu River in Year 2014

Observed and Simulated Water Level in Balu River 5 4.5 4

) 3.5 3 2.5 Simulated 2 Observed 1.5 Water Level (mPWD 1 0.5 0 7-Dec 27-Dec 16-Jan 5-Feb 25-Feb 17-Mar 6-Apr 26-Apr 16-May Date

Figure 6.39 : Validation of the numerical model of Balu River in Year 2015

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Observed and Simulated Water Level in Buriganga River

5 4.5 4

) 3.5 3 2.5 Simulated 2 Observed 1.5 Water Level (mPWD 1 0.5 0 21-Jan 10-Feb 2-Mar 22-Mar 11-Apr 1-May 21-May 10-Jun Date

Figure 6.40: Calibration of the numerical model of Buriganga River in Year 2014

Observed and Simulated Water Level in Buriganga River

5 4.5

) 4 3.5 3 2.5 Simulated 2 1.5 Observed

Water Level (mPWD Level Water 1 0.5 0 16-Jan 5-Feb 25-Feb 17-Mar 6-Apr 26-Apr 16-May 5-Jun 25-Jun Date

Figure 6.41: Validation of the numerical model of Buriganga River in Year 2015

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Observed and Simulated Water Level in Sitalakhya River 8

) 6

4 Simulated 3 Observed

Water Level (mPWD 2

0 28-Aug 17-Sep 7-Oct 27-Oct 16-Nov 6-Dec 26-Dec Date

Figure 6.42: Calibration of the numerical model of Sitalakhya River in Year 2014

Observed and Simulated Water Level in Sitalakhya River

) 6

4 Simulated 3 Observed

Water Level Water Level (mPWD 2

0 24-Aug 13-Sep 3-Oct 23-Oct 12-Nov 2-Dec 22-Dec 11-Jan Date

Figure 6.43: Validation of the numerical model of Sitalakhya River in Year 2015

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Observed and Simulated Water Level in Dhaleswari River

10 9

8 ) 7 6 5 Simulated 4 3 Observed Water Level (mPWD 2 1 0 9-Aug 29-Aug 18-Sep 8-Oct 28-Oct 17-Nov 7-Dec 27-Dec 16-Jan Date

Figure 6.44: Calibration of the numerical model of Dhaleswari River in Year 2014

Observed and Simulated Water Level in Dhaleswari River 10 9

8 7 6 5 Simulated 4 Observed 3

Water Level (mPWD) 2 1 0 24-Aug 13-Sep 3-Oct 23-Oct 12-Nov 2-Dec 22-Dec 11-Jan Date

Figure 6.45: Validation of the numerical model of Dhaleswari River in Year 2015

6.9.4 Model Results for Various Abstraction Scenarios An analysis was carried out to see the impact of abstraction of water on the total river network and in all reaches. In Figure 6.46 the abstraction points are shown in green circle. Water was abstracted from the intake point for the purpose of supply to Dhaka city in January 13 m3/s, February 30 m3/sec and subsequent months 60 m3/s (as found in Table 6.8 after subtracting the environmental flow)

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which is marked green and model was run to see the effect on velocity, water level and depth of water in all the reaches. Details of model run scenario for different withdrawal scenario have been shown in Table 6.10. In the subsequent paragraphs, the effect of monthly withdrawal of water on the peripheral river reaches has been shown in Figures and Tables.

146

Figure 6.46: Map showing the abstraction points in the river network

147

Table 6.9 : Scenarios of HD Model Run

Scenario Intake Points River Months Water Abstraction MLD Sources Quantity (m3/s) 1 Intake 6 Dhaleswari Jan 13 1100 2 Intake 4 Shitalakya Feb 05 2578 Intake 6 Dhaleswari 25 3 Intake 4 Shitalakya Mar 11 5076 Intake 6 Dhaleswari 42 4 Intake 4 Shitalakya Apr 20 5076 Intake 6 Dhaleswari 40 5 Intake 1 Turag May 10 5076 Intake 3 Balu 20 Intake 4 Shitalakya 10 Intake 6 Dhaleswari 20 6 Intake 1 Turag Jun 10 5076 Intake 3 Balu 10 Intake 5 Buriganga 10 Intake 4 Shitalakya 15 Intake 6 Dhaleswari 15 7 Intake 1 Turag Jul 10 5076 Intake 2 Tongi 05 Intake 3 Balu 10 Intake 5 Buriganga 10 Intake 4 Shitalakya 15 Intake 6 Dhaleswari 10 8 Intake 1 Turag Aug 10 5076 Intake 2 Tongi 10 Intake 3 Balu 10 Intake 5 Buriganga 10 Intake 4 Shitalakya 10 Intake 6 Dhaleswari 10 9 Intake 1 Turag Sep 10 5076 Intake 2 Tongi 10 Intake 3 Balu 10 Intake 5 Buriganga 10 Intake 4 Shitalakya 10 Intake 6 Dhaleswari 10 10 Intake 1 Turag Oct 10 5076 Intake 2 Tongi 10 Intake 3 Balu 10 Intake 5 Buriganga 10 Intake 4 Shitalakya 10 Intake 6 Dhaleswari 10 11 Intake 4 Shitalakya Nov 30 5076 Intake 6 Dhaleswari 30 12 Intake 4 Shitalakya Dec 06 3807 Intake 6 Dhaleswari 39

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6.9.5 Analysis of Turag River

Turag river flows through the areas including Gazipur sadar, Savar, Pallabi and Mirpur before a branch of Bangshi river meeting the Turag. To analyze the variation of flow velocity in Turag river, velocity in base scenario was found 0.12 m/sec and after abstraction of water was found 0.06 m/sec. Figures 6.47 shows the change in velocity in Turag river.

DMP Existing Geometry Plan: 1) Base Flow 17-Nov-17 2) Withdrawal 16-Nov-17 Turag 332 0.18 Legend

Vel Chnl 01JAN2014 2400 - Base Flow Vel Chnl 01JAN2014 2400 - Withdrawal 0.16

0.14

0.12

0.10

0.08

0.06 Vel Left (m/s), Vel Chnl (m/s), Vel Right (m/s) (m/s), Vel Right (m/s), Vel Chnl VelLeft

0.04

0.02

0.00 0 2000 4000 6000 8000 10000 Main Channel Distance (m )

Figure 6.47: Variation of Velocity Before and After Abstraction along the Turag River

In Turag river water is abstracted and water level was lowered from 1.50 metre to 0.30 metre as shown in Figure 6.48.

DMP Existing Geometry Plan: 1) Base Flow 12-Nov-17 2) Withdrawal 12-Nov-17 Turag 332 3 Legend

WS 22JAN2014 2400 - Bas e Flow WS 22JAN2014 2400 - Withdrawal Ground 2

0 Elevation (m)Elevation -1

-2

-3

-4 0 2000 4000 6000 8000 10000 Main Channel Distance (m )

Figure 6.48 : Variation of Water Level Before and After Abstraction along the Turag River 149

The depth of water in Turag River is reduced from 1.60 metre to 0.40 metre after abstraction of water as shown in Figure 6.49.

Figure 6.49: Variation of Water Depth Before and After Abstraction along the Turag River

6.9.6 Analysis of Tongi Khal

Tongi khal flows through the Gazipur sadar and Uttara having Gazipur sadar at left side of the left bank and Uttara at right of the right bank.To analyze the variation of flow velocity in Tongi khal, 4 cross sections along the longitudinal reach of Tongi khal have been selected. Analysis on of the Tongi khal, velocity remains minimum velocity happended during abstraction less than zero. Figure 6.50 shows the change in velocity in Tongi khal.

Figure 6.50: Variation of Velocity Before and After Abstraction along the Tongi River

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The water level in Tongi khal is reduced from 1.2 metre to 0.5 metre after abstraction of water as shown in Figure 6.51.

Figure 6.51 : Variation of Water Level Before and After Abstraction along the Tongi Khal

The depth of water in Tongi khal is reduced from 1.5 metre to 0.80 metre after abstraction of water as shown in Figure 6.52.

DMP Existing Geometry Plan: 1) Base Flow 12-Nov-17 2) Withdrawal 12-Nov-17 Tongi Khal 321 7 Legend

Max Chl Dpth 02JAN2014 2400 - Base Flow Max Chl Dpth 02JAN2014 2400 - Withdrawal

Max Chl Dpth (m) Dpth MaxChl 3

0 0 2000 4000 6000 8000 10000 12000 14000 Main Channel Distance (m ) Figure 6.52: Variation of Water Depth Before and After Abstraction along the Tongi

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6.9.7 Analysis of Balu River:

To analyze the spatial and temporal variation of flow velocity in Balu river 4 cross sections along the longitudinal reach of Balu have been selected. The velocity varied from 0.25 m/s to 0.20 m/s in magnitude during abstraction of water from the base scenario. Figure 6.53 shows the spatial and temporal variation of velocities along the Balu river throughout the year.

DMP Existing Geometry Plan: 1) 16 08-Nov-17 2) Balu 111 0.40 Legend

Vel Chnl 07JAN2014 2400 - 16 Vel Chnl 23JAN2015 2400 - 16 0.35

0.30

0.25

0.20

0.15 Vel Left (m/s), Vel Chnl (m/s), Vel Right (m/s) (m/s), Vel Right (m/s), Vel Chnl VelLeft

0.10

0.05

0.00 0 1000 2000 3000 4000 5000 6000 7000 Main Channel Distance (m ) Figure 6.53: Variation of Velocity Before and After Abstraction along the Balu River

In month of January water level decreased from 2.0 metre to 1.35 metre for Balu river. In Figure 6.54 the water level decreased is shown due to abstraction.

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DMP Existing Geometry Plan: 1) Base Flow 12-Nov-17 2) Withdrawal 12-Nov-17 Balu 112 3 Legend

WS 15JAN2014 2400 - Bas e Flow WS 15JAN2014 2400 - Withdrawal Ground 2

0 Elevation (m)Elevation -1

-2

-3

-4 0 5000 10000 15000 20000 Main Channel Distance (m ) Figure 6.54: Variation of Water Level Before and After Abstraction along Balu River

The depth of water in Balu River is reduced from 3.0 metre to 2.0 metre after abstraction of water as shown in Figure 6.55.

DMP Existing Geometry Plan: 1) Base Flow 12-Nov-17 2) Withdrawal 12-Nov-17 Balu 112 6 Legend

Max Chl Dpth 15JAN2014 2400 - Base Flow Max Chl Dpth 15JAN2014 2400 - Withdrawal

3 Max Chl Dpth (m) Dpth MaxChl

0 0 5000 10000 15000 20000 . Main Channel Distance (m ) Figure 6.55 : Variation of Water Depth Before and After Abstraction along the Balu River

6.9.8 Analysis of Buriganga River

Buriganga river flows through the areas including Mohammadpur, Hazaribagh, kamrangir char, Keraniganj and Narayanganj sadar part. Analysis on maximum velocity for the January month shown that velocity of 0.15 m/s velocity happended during the abstraction having magnitude of 0.10 m/s. Figure 6.56 shown the change in velocity in Buriganga river the month of January. 153

Figure 6.56 : Variation of Velocity Before and After Abstraction along the Buriganga River The water level in Buriganga river is reduced from 2.0 metre to 0.5 metre after abstraction of water as shown in Figure 6.57.

DMP Existing Geometry Plan: 1) Base Flow 12-Nov-17 2) Withdrawal 12-Nov-17 Dhaleshwari 331 5 Legend

WS 19JAN2014 2400 - Bas e Flow WS 19JAN2014 2400 - Withdrawal Ground

-5 Elevation (m)Elevation

-10

-15

-20 0 5000 10000 15000 20000 25000 Main Channel Distance (m )

Figure 6.57: Variation of Water Level Before and After Abstraction along the Buriganga River

The depth of water in Buriganga River is reduced from 6.5 metre to 4.54 metre after abstraction of water as shown in Figure 6.58.

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DMP Existing Geometry Plan: 1) Base Flow 17-Nov-17 2) Withdrawal 16-Nov-17 Buriganga 331 Legend

Max Chl Dpth 01JAN2014 2400 - Base Flow Max Chl Dpth 01JAN2014 2400 - Withdrawal 30

15 Max Chl Dpth (m) Dpth MaxChl

0 5000 10000 15000 20000 25000 Main Channel Distance (m ) Figure 6.58 : Variation of Water Depth Before and After Abstraction along the Buriganga River

6.9.9 Analysis of Sitalakhya River

Sitalakhya river flows through the Gazipur and Rupganj before the river Balu meeting at Demra. After meeting Balu the river Sitalakhya flows through the area Demra and Narayanganj. To analyze the variation of flow velocity due to abstraction change from 0.03 m/s to 0.025 m/s in the river Sitalakhya. Figure 6.59 as shown the change in velocity in Sitalakhya river for the month of January.

DMP Existing Geometry Plan: 1) 16 08-Nov-17 2) Lakhya 261 Legend

Vel Chnl 07JAN2014 2400 - 16 Vel Chnl 23JAN2015 2400 - 16

0.10

0.08

0.06 Vel Left (m/s), Vel Chnl (m/s), Vel Right (m/s) (m/s), Vel Right (m/s), Vel Chnl VelLeft

0.04

0.02 0 10000 20000 30000 40000 50000 Main Channel Distance (m ) Figure 6.59: Variation of Velocity Before and After Abstraction along the Shitalakya River

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The water level in Sitalakhya River is reduced from 1.98 metre to 0.40 metre after abstraction of water as shown in Figure 6.60.

DMP Existing Geometry Plan: 1) Base Flow 17-Nov-17 2) Withdrawal 16-Nov-17 Lakhya 261 2 Legend

WS 01JAN2014 2400 - Bas e Flow WS 01JAN2014 2400 - Withdrawal Ground 0

-2

-4 Elevation (m) Elevation -6

-8

-10

-12 0 10000 20000 30000 40000 50000 Main Channel Distance (m)

Figure 6.60: Variation of Water Level Before and After Abstraction along the Sitalakhya River

The depth of water in Sitalakhya River is reduced from 8.8 metre to 5.50 metre after abstraction of water as shown in Figure 6.61.

DMP Existing Geometry Plan: 1) Base Flow 12-Nov-17 2) Withdrawal 12-Nov-17 Lakhya 261 14 Legend

Max Chl Dpth 15JAN2014 2400 - Base Flow Max Chl Dpth 15JAN2014 2400 - Withdrawal

10 Max Chl Dpth (m) Dpth MaxChl 8

4 0 10000 20000 30000 40000 50000 Main Channel Distance (m ) Figure 6.61: Variation of Water Depth Before and After Abstraction along the Sitalakhya River

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6.9.10 Analysis of Dhaleswari River

Dhaleshwari River flows through the areas including Narayanganj sadar part within the periphery of Dhaka city. The velocity was .030 m/s in base scenario and after te abstraction the flow became 0.025m/s. Figure 6.62 as shown the change in velocity in Dhaleswari river for the month of January.

DMP Existing Geometry Plan: 1) 16 08-Nov-17 2) Dhales wari 184 0.035 Legend

Vel Chnl 07JAN2014 2400 - 16 Vel Chnl 23JAN2015 2400 - 16

0.030

0.025

0.020 Vel Left (m/s), Vel Chnl (m/s), Vel Right (m/s) (m/s), Vel Right (m/s), Vel Chnl VelLeft

0.015

0.010 0 2000 4000 6000 8000 10000 12000 Main Channel Distance (m )

Figure 6.62: Variation of Velocity Before and After Abstraction along the Dhaleswari River

The water level in Dhaleswari River is reduced from 2.28 metre to 1.5 metre after abstraction of water as shown in Figure 6.63.

DMP Existing Geometry Plan: 1) Base Flow 17-Nov-17 2) Withdrawal 16-Nov-17 Dhales wari 181 3 Legend

WS 01JAN2014 2400 - Bas e Flow WS 01JAN2014 2400 - Withdrawal Ground 2

0 Elevation (m) Elevation -1

-2

-3

-4 0 10000 20000 30000 40000 50000 Main Channel Distance (m) Figure 6.63: Variation of Water Level Before and After Abstraction along the Dhalewari River 157

The depth of water in Dhaleswari River is reduced from 5.15 metre to 3.65 metre after abstraction of water as shown in Figure 6.64.

DMP Existing Geometry Plan: 1) Base Flow 12-Nov-17 2) Withdrawal 12-Nov-17 Dhales wari 181 5.5 Legend

Max Chl Dpth 15JAN2014 2400 - Base Flow Max Chl Dpth 15JAN2014 2400 - Withdrawal 5.0

4.5

4.0

3.5 Max Chl Dpth (m) Dpth MaxChl

3.0

2.5

2.0

1.5 0 10000 20000 30000 40000 50000 Main Channel Distance (m )

Figure 6.64 : Variation of Depth Before and After Abstraction along the Dhaleswari River

6.10 Summary Results for the Base and Withdrawal Scenarios

Summarizing all the above data, the table is prepared of base and withdrawal condition of all months of all rivers. It indicated that the depth of the rivers remain low for Turag, and Tongi where as others rivers have more depth. The Tables 6.9 to 6.20 of all peripheral rivers for January to December are tabulated below:

Table 6.10: Model Results for Base and Withdrawal Scenario of January

River Water Level (m) Velocity (m/s) Depth(m) Scenario Base Withdrawal Base Withdrawal Base Withdrawal Turag 1.50 0.30 0.12 0.06 1.60 0.40 Tongi 1.2 0.50 0.00 0.00 1.5 0.8 Balu 2.0 1.35 0.25 0.20 3.0 2.0 Buriganga 2.0 0.50 0.15 0.10 6.5 4.54 Shitalakya 1.98 0.40 0.03 0.025 8.8 5.50 Dhaleswari 2.28 1.5 0.030 0.025 5.15 3.65

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Table 6.11: Model Results for Base and Withdrawal Scenario of February

River Water Level (m) Velocity (m/s) Depth(m) Scenario Base Withdrawal Base Withdrawal Base Withdrawal Turag 2.05 0.85 0.34 0.05 2.20 1.95 Tongi 1.99 0.36 0 0 2.75 1.87 Balu 1.95 0.52 0.07 0.01 2.95 2.20 Buriganga 2.93 0.43 0.04 0.01 6.00 4.85 Shitalakya 2.94 0.46 .02 0.01 9.65 8.50 Dhaleswari 2.97 0.48 0.04 0.03 12.40 10.75

Table 6.12: Model Results for Base and Withdrawal Scenario of March

River Water Level (m) Velocity (m/s) Depth(m) Scenario Base Withdrawal Base Withdrawal Base Withdrawal Turag 2.40 1.40 0.15 0.07 2.90 2.28 Tongi 2.35 1.60 0.01 0.01 3.12 2.51 Balu 3.35 0.92 0.02 0.01 4.79 3.42 Buriganga 3.20 0.80 0.02 0.01 5.90 4.80 Shitalakya 3.18 0.85 0.01 0.0 8.40 6.90 Dhaleswari 3.35 0.85 0.05 0.01 12.30 9.19

Table 6.13: Model Results for Base and Withdrawal Scenario of April

River Water Level (m) Velocity (m/s) Depth(m) Scenario Base Withdrawal Base Withdrawal Base Withdrawal Turag 2.85 1.85 0.09 0.04 3.94 2.88 Tongi 2.83 1.12 0.01 0.01 3.87 2.16 Balu 3.47 1.20 0.35 0.11 4.05 3.20 Buriganga 3.79 1.54 0.02 0.01 6.49 5.24 Shitalakya 3.82 2.12 0.03 0.01 9.44 7.60 Dhaleswari 3.91 2.58 0.15 0.11 12.15 9.50

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Table 6.14: Model Results for Base and Withdrawal Scenario of May

River Water Level (m) Velocity (m/s) Depth(m) Scenario Base Withdrawal Base Withdrawal Base Withdrawal Turag 3.39 2.75 0.08 0.05 4.04 3.39 Tongi Khal 3.30 2.47 0.01 0.01 4.40 3.52 Balu 3.36 2.41 0.34 0.18 5.13 4.51 Buriganga 3.27 2.04 0.23 0.13 5.97 4.23 Shitalakya 3.20 2.01 0.05 0.04 9.59 8.34 Dhaleswari 3.25 2.00 0.14 0.10 12.60 9.35

Table 6.15: Model Results for Base and Withdrawal Scenario of June

River Water Level (m) Velocity (m/s) Depth(m) Scenario Base Withdrawal Base Withdrawal Base Withdrawal Turag 3.27 6.09 0.93 0.90 4.65 3.47 Tongi Khal 3.67 5.27 0.12 0.11 4.71 3.31 Balu 3.77 3.58 0.37 0.29 4.66 4.02 Buriganga 4.80 3.64 0.23 0.21 7.47 5.31 Shitalakya 4.69 3.44 0.23 0.17 10.11 8.24 Dhaleswari 4.80 3.64 0.23 0.21 13.75 11.30

Table 6.16: Model Results for Model Results for Base and Withdrawal Scenario of July

River Water Level (m) Velocity (m/s) Depth(m) Scenario Base Withdrawal Base Withdrawal Base Withdrawal Turag 4.76 3.22 0.58 0.52 5.90 4.63 Tongi khal 3.05 2.16 0.11 0.09 5.39 4.65 Balu 3.31 5.62 0.16 0.15 6.11 5.72 Buriganga 5.50 5.89 0.31 0.30 7.46 6.56 Shitalakya 6.00 5.30 0.38 0.33 10.92 9.18 Dhaleswari 7.08 5.34 0.75 0.68 14.92 12.18

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Table 6.17: Model Results for Base and Withdrawal Scenario of August

River Water Level (m) Velocity (m/s) Depth(m) Scenario Base Withdrawal Base Withdrawal Base Withdrawal Turag 5.57 3.03 0.47 0.41 5.98 4.44 Tongi khal 4.76 2.29 0.08 0.06 5.80 3.34 Balu 4.15 2.46 0.35 0.36 5.25 3.56 Buriganga 5.33 4.72 0.29 0.28 7.29 6.40 Shitalakya 5.75 5.36 0.35 0.30 10.80 9.09 Dhaleswari 5.95 5.21 0.71 0.65 15.05 12.79

Table 6.18: Model Results for Base and Withdrawal Scenario of September

River Water Level (m) Vel (m/s) Depth(m) Scenario Base Withdrawal Base Withdrawal Base Withdrawal Turag 3.69 2.08 0.39 0.34 4.69 3.49 Tongi khal 4.86 4.33 0.12 0.1 5.91 5.39 Balu 4.59 3.93 0.07 0.07 5.69 4.57 Buriganga 5.49 4.81 0.23 0.22 7.68 5.48 Shitalakya 6.43 5.64 0.42 0.36 11.39 9.24 Dhaleswari 5.33 4.58 0.43 0.40 15.17 13.42

Table 6.19: Model Results for Base and Withdrawal Scenario of October

River Water Level (m) Velocity (m/s) Depth(m) Scenario Base Withdrawal Base Withdrawal Base Withdrawal Turag 3.11 2.69 1.07 0.95 3.52 3.11 Tongi khal 3.19 2.02 0.24 0.25 4.20 3.06 Balu 4.72 4.17 0.19 0.17 5.82 5.27 Buriganga 4.76 4.25 0.27 0.27 6.85 5.66 Shitalakya 4.88 3.52 0.65 0.54 11.24 10.48 Dhaleswari 4.18 3.12 0.68 0.63 13.02 11.26

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Table 6.20: Model Results for Base and Withdrawal Scenario of November

River Water Level (m) Velocity (m/s) Depth(m) Scenario Base Withdrawal Base Withdrawal Base Withdrawal Turag 2.68 1.96 0.21 0.14 2.94 2.37 Tongi khal 1.87 1.55 0.13 0.12 2.92 2.59 Balu 3.64 2.90 0.06 0.04 4.74 4.00 Buriganga 3.66 2.92 0.03 0.02 5.34 4.60 Shitalakya 3.64 2.89 0.05 0.04 9.70 8.95 Dhaleswari 3.64 2.89 0.11 0.10 12.48 10.73

Table 6.21: Model Results for Base and Withdrawal Scenario of December

River Water Level (m) Velocity (m/s) Depth(m) Scenario Base Withdrawal Base Withdrawal Base Withdrawal Turag 1.62 0.52 0.21 0.17 2.03 1.19 Tongi khal 2.88 0.13 0.04 0.03 2.11 1.25 Balu 2.61 1.50 0.11 0.05 3.11 2.60 Buriganga 2.61 1.51 0.03 0.02 4.86 3.90 Shitalakya 2.59 1.49 0.1 0.08 8.65 7.55 Dhaleswari 3.50 1.79 0.08 0.06 11.83 10.02

6.11 Summary and Discussions After detail analysis by flow and water level hydrograph, flow duration curve and HEC RAS model and availability water sources of future requirements following comments can be made:

i. The potential sources have been identified at the beginning of analysis. Then the flow and water level hydrograph were prepared of 10 years from 2006 to 2016. From the Table 6.3, it was marked that the lowest flow occurred in the dry season for peripheral rivers specially Turag and Tongi but other rivers have sufficient water to be supplied for Dhaka city. From HEC RAS model study, it was further validated that in Table 6.10 lowest water level occurred in dry season specially Turag river and Tongi khal. It is understood that water can be easily abstracted in the monsoon and post monsoon season for other rivers.

ii. The water level hydrograph were constructed for all peripheral and large rivers and depths were calculated in Table 6.8. It was found from navigational point of view, Turag river and Tongi khal is not navigable in dry seasons. But in the monsoon and post monsoon season the peripheral rivers are easily navigable for class III routes. 162

iii. From the Table 6.5, water quality of per ipheral rivers around Dhaka city was analysed with respect to pH, turbidity, dissolved oxygen (DO), biochemical ox ygen demand (BOD), chemical oxygen demand (COD), ammonium (NH4+), nitrate (NO3 ), phosphate(PO4 3-), chromium (Cr), mercury (Hg), lead (Pb ), Zinc (Zn) etc found that water cannot be abstracted in dry season for Tongi, Turag, Balu and Buriganga from peripheral rivers and can be abstracted from Dhaleswari and Sitalakhya throughout the year. All the peripheral rivers are suitable for abstraction for six months from May to October of the year. It is also understood that water quality needs to be improved for sustainable surface water supply in Dhaka city. From the analysis, it was also proved that industrial waste and other pollutants need to be stopped for survival of peripheral city.In the month of January, 13 m3/sec can be supplied from peripheral rivers where as in other months it would not be sufficient to supply for Dhaka city. The primary source of surface water is the peripheral rivers around the city. Restoration and rehabilitation of these rivers are mandatory to increase the flow as well as to recover the water quality. It is revealed that during monsoon water is obtainable and sufficient amount of water can be abstracted with reasonable treatment arrangement. iv. In the Table 6.8, it was found out that considering average flow of water, sustainable environmental flow and quality parameter, the peripheral rivers can alone solve the water crisis in Dhaka city. The surface water supply can be further increased with the improvement of quality parameter. The Padma and Meghna are the two major rivers located at some distance from the city. These rivers have mammoth amount of water with good quality. These rivers should only be incorporated to the water supply system after making optimum use of peripheral rivers.

v. In HEC-RAS model analysis, it was found that the water level, velocity and depth decreased with the withdrawal of water from the peripheral rivers. Abstraction of water changes in thermal regime and water chemistry in 90 % of the above calculation found that flow reduction significantly decreased water velocity 16-80% in all reaches, while depth 30–70% and water level 35–75% also decreased. Mostly, the velocity decreased maximum in peripheral rivers specially in dry season in each year after the abstraction of water. In monsoon season, the water remains significant to be supplied as source of surface water. In dry season, Sitalakhya and Dhaleswari river can be a source of supply. This supply

163

augmented by Padma and Meghna. Padma and Meghna always remain a potential source throughout the river for source of water supply for Dhaka city. If the surface water can be fully utilized, it will further reduce the pressure on ground water. vi. It can be referred from the above discussions that the only surface water supply system from peripheral and large rivers can elucidate the fresh water crisis of the city where minimum reliance will be given on extraction of groundwater. Subsequently, outcome of the study of available options were further examined and validated by HEC RAS model to find out the best possible option to solve the fresh water crisis of the city. The availability of Padma and Meghna and peripheral rivers water supply can solve the fresh water requirement of the city as discussed in this chapter. The amount available from the surface water sources was evaluated as per different criteria in Chapter 7.

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CHAPTER SEVEN

EVALUATION OF COST EFFECTIVENESS OF SURFACE WATER SOURCES 7.1 General

Evaluation of cost effectiveness is an important aspect to be considered after calculation of future estimated demand and probable surface water sources. Cost effectiveness analysis is a decision-making tool to achieve a desired output with regard to their resource utilization (cost) and outcomes (effectiveness). Cost effectiveness analysis can be used to find the least cost means to achieve the required surface water, or to estimate the expected costs of achieving a particular demand. It can also be used to measure the cost of various surface water treatment plants for achieving the required capacity. Cost effectiveness analysis has been used for estimating the cost of capital expenditure, operational expenditure and other associated cost. On the basis of cost effectiveness analysis, recommendations are made for addressing development needs while contributing to an effective climate change response and sustainable development. Water demand for the future has been estimated mainly for residential, non-residential and firefighting requirement. The main basis of estimating the demand is population projection for the time under consideration i.e. 2017 to 2035.The total production capacity, however, considers physical loss or leakage from the transmission and distribution pipelines and appurtenances. Demand of the water is continuously increasing but the availability of the water sources needs to be ensured. In order to fulfill our demands it is absolutely essential to maintain, conserve and use water resources very carefully. Water supply in Dhaka faces numerous challenges such as acute water shortage, inadequate sanitation, polluted river water, unplanned urban development, and the existence of large slums where more than one third of its population lives. Residents of Dhaka enjoy one of the lowest water tariffs in the world which limits any private sector investment opportunity. The Dhaka area will be approximately 617 km2 where water needs to be distributed by the surface water in combination with ground water. In this study, detail analysis is being carried out in order to find out the suitable sources to provide the effective solution of water supply problem. Figure 7.1 shows the demand components over the period from 2017 to 2035.

165 Prediction of Demand components of Dhaka City 6000 5000 Residential (MLD)

4000 Loss (MLD) 3000 Fire Fighting (MLD) 2000 Other (MLD) Demand(MLD) 1000 Total demand (MLD) 0 2017 2020 2025 2030 2035 Year

Figure 7.1: Prediction of demand components of Dhaka city

It is found from the study that the present area will increase from 404 km2 to 617 km2 in 2035, covering its entire jurisdiction of Dhaka city and some additional areas with future extension. As a result of increase in domestic, industrial, commercial and other uses in the total area of 617 km2, the total demand will rise to 5105 MLD in 2035. If we consider that leakage from the system would be reduced from the present level the total required production capacity would increase in 2035. This is an increase of 2.5 times instead of 2 times. However, during the same period, population increase will be 3.2 times and service area increase will be 1.5 times. Estimated production capacity for meeting the demand shows that by the year 2035 the total demand is expected to rise to 5105MLD in the 617 km2 of Dhaka city area. To meet the requirement, peripheral rivers are the best sources. More options are limited to harnessing the water resources of Meghna and Padma rivers. It was found that sufficient water of adequate quality is available in these two rivers throughout the year. If proper measures are taken to prevent pollution and availability of the peripheral rivers, dependency on large rivers will be reduced.

7.2 Suggested Surface Water Withdrawal for Treatment

In Chapter 6, detail analyses of water availability have been done through mathematical model, considering environmental flow and navigability (Table 6.8). In order to assess appropriate cost estimate for the suggested water sources, net water availability has been shown from Figure 7.2 to 7.9 for the rivers under study. In all the figures, the limit of withdrawal has been shown in red line.

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Net Water Availability for Balu River 35000

30000

25000

20000 Minimum limit for suggested water 15000 withdrawal Available Available MLD 10000

5000

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Figure 7.2: Net Water Availability of Balu River

Net Water Availability for Turag River 35000

30000

25000 Minimum limit for 20000 suggested water withdrawal 15000 Avalable Avalable MLD 10000

5000

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Figure 7.3: Net Water Availability of Turag River

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Net water Availability for Tongi khal 3500

3000

2500

2000 Minimum limit for 1500 suggested water withdrawal Available Available MLD 1000

500

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Figure 7.4: Net Water Availability of Tongi River

Net water Availability for Buriganga River

35000 30000

25000 20000 Minimum limit for suggested water 15000 withdrawal

Available Available MLD 10000 5000 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Figure 7.5: Net Water Availability of Buriganga River

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Net Water withdrawal availability for Sitalakhya River 50000 45000 40000

35000 30000 25000 Minimum limit for 20000 suggested water Available Available MLD 15000 withdrawal 10000 5000 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Figure 7.6: Net Water Availability of Sitalakhya River

Net Water withdrawal availability for Dhaleshwari River 160000

140000

120000

100000

80000 Minimum limit for 60000

Available Available MLD suggested water withdrawal 40000

20000

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Figure 7.7: Net Water Availability of Dhaleshwari River

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Net Water withdrawal availability for Padma River 4500000 4000000 3500000

3000000 2500000 2000000 Minimum limit for suggested water Available Available MLD 1500000 withdrawal 1000000 500000 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Figure 7.8: Net Water Availability of Padma River

Net Water withdrawal availability for Meghna River 700000

600000

500000

400000 Minimum limit for 300000 suggested water

Available Available MLD withdrawal 200000

100000

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Figure 7.9: Net Water Availability of Meghna River

The net water availability of the peripheral rivers are gradually decreasing due to encroachment of the river banks, disturbing the courses of rivers, fewer intakes from the upstream rivers, filling up the rivers for urbanization, sludge and solid waste disposal in the river bed, etc. As a result, SWTPs do not receive adequate raw water for optimum production. This situation aggravates more during dry season, when the water level of the rivers are minimum. The availability of water in the peripheral rivers and major rivers found that minimum water level exits in dry period.

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7.3 Evaluation Criteria

The evaluation criteria are water availability, water quality and cost effectiveness. These criteria have been determined the availability of sources by data analysis and model output (Chapter 6). Quality have been determined by various analyses and weighted against their results (Chapter 5). More so cost effectiveness was analysed by different capital and maintenance cost including pipe installation cost. Considering all the evaluation criteria, assessment has been made to find out the suitability of the sources. In this study, index is a term indicates the ranking of similar items to assess the suitability among the items under evaluation. For instance, index value one (1) means highest and eight (8) means lowest ranking. The index as per the availability data is shown in Table 7.1.In this table 7.1, index value has been given based on excess available water on the river sources and operational period. It is seen that all the river sources have the available water for the given operational periods as indexed between 1 and 4. Table 7.1 Water Availability Index

Name of the Allowable Operational Index River Abstraction for June Period(Months) (MLD) Turag 2208 6 4 Tongi Khal 180 6 5 Balu 574 6 4 Buriganga 8339 6 3 Sitalakhya 11223 10 2 Dhaleshwari 43118 12 1 Padma 2868220 12 1 Meghna 174152 12 1

7.3.1 Water Quality of Peripheral Rivers As described in Chapter 5, it was examined that water quality of the peripheral rivers has been deteriorated severely due to increase pressure of urbanization and industrialization. Rivers receive discharges of domestic, industrial, agricultural waste and sewage. Few important water quality parameters of these rivers have been shown at Figure 7.10. From the figure it is clear that, present state of pollution of these rivers is much higher than the limits set by WHO and DOE, Bangladesh.

171

250

200

BOD5 150 Ammonia Suspended Solid Color 100 Turbidity

Quality Quality Parameter(mg/l) Fecal Coliform pH 50 Lead

0 Bangladesh Buriganga Sitalakhya Balu River Tongi Khal Turag River Standard River River Surface Water Sources

Figure 7.10: Important Water Quality Parameters of Peripheral Rivers

7.3.2 Water Quality of Large Rivers

Water quality of River Padma and Meghna is much better than that of the peripheral rivers. Figure 7.11 shows the comparison of some water quality parameters between these two large rivers and one of the peripheral rivers (Buriganga). In Table 7.2 Water Quality Index is shown as per the quality parameter.

Large Rivers

250

200 BOD5 Ammonia

150 Suspended Solid

mg/l 100 Color Turbidity 50 Chromium pH 0 Bangladesh Buriganga River Padma River Meghna River Lead Standards Fecal Coliform (ECR1997) Surface Water Sources

Figure 7.11: Comparison of water quality parameters between two large rivers (Padma and Meghna) and one of the peripheral rivers (Buriganga)

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Table 7.2 Dry Period Water Quality Index

Name of the River Weightage/Index Turag 7 Tongi Khal 8 Balu 6 Buriganga 5 Sitalakhya 3 Dhaleshwari 4 Padma 1 Meghna 2

7.4 Cost Estimation

Cost of water supply will include capital expenditure, operation expenditure and overall lifetime cost. After detail calculation it has been evaluated in separated three heads. The estimation can be discussed as follows: 7.4.1 Capital Expenditure

The total cost of water treatment plant includes capital expenditure, operational expenditure and lifetime expenditure. For calculation of the cost, the taka 6.678 crore per MLD of water has been considered in this study as information commensurate with the Saidabad SWTP. The capital expenditure, operational expenditure and lifetime expenditure of a WTP can be seen in Table 7.3. Table 7.3 Total Water Treatment Plant (WTP) Cost

Rivers Withdrawal Capital Operational LIFETIME Total WTP MLD Expenditure Expenditure Operational Cost WTP WTP Expenditure (Crore Tk) (Crore Tk) (Crore Tk) (Crore Tk) Turag 450 3009 51 2550 5559 Tongi Khal 180 1202 51 2550 3752 Balu 450 3009 90 4514 7523 Buriganga 450 3009 90 4514 7523 Sitalakhya 450 3009 90 4514 7523 Dhaleshwari 450 3009 90 4514 7523 Padma 500 3339 100 5009 8348 Meghna 500 3339 100 5009 8348

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7.4.2 Operational Expenditure

The operational expenditure includes the cost of the pipe and its capital and operational expenditure with lifetime cost. Table 7.4 shows the operational expenditure incurred for all the surface water sources. Table 7.4 Operational Expenditure

Name of the Pipeline Capital Operational Lifetime Total Pipeline Rivers Length(km) Expenditure Expenditure Operational Cost(Crore Tk) pipeline pipeline Expenditure (Crore Tk) (Crore Tk) (Crore Tk) Turag 7 401 12 602 1003 Tongi Khal 9 401 12 602 1003 Balu 13 580 17 869 1449 Buriganga 10 446 13 669 1115 Sitalakhya 13 580 17 869 1445 Dhaleshwari 15 669 20 1003 1672 Padma 40 1783 54 2675 4458 Meghna 33 1471 44 2207 3678

7.4.3 Cost of Water per MLD

The cost of water in terms of Million Litre per Day (MLD) includes the river restoration cost and overall lifetime cost. All unit costs are considered in this study based on the ongoing Saidabad SW Treatment plant (SWTP) of DWASA (IWM, 2014). In the report 2000 crore taka for the peripheral rivers was estimated. However, for this study amount of rivers restoration costs have been assumed based on the water quantity and quality required for the suggested demand as shown in Table 7.3. The cost of water per MLD is shown in Table 7.5:

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Table 7.5 Cost of Water per MLD

Name of the River Restoration Overall Lifetime Cost per MLD(Crore Tk) Rivers Cost(Crore Tk) Cost(Crore Tk) Turag 750 6003 12 Tongi Khal 750 6003 12 Balu 750 9276 19 Buriganga 1500 10026 20 Sitalakhya 500 9137 18 Dhaleshwari 500 9694 19 Padma 0 12806 25.61 Meghna 0 11691 23.38

7.5 Cost Effectiveness

The cost effectiveness index is obtained from the estimated cost for the river restoration and surface water treatment for the ready supply of water. The index of the rivers as per cost effectiveness is shown in Table 7.6 in which, lower the cost higher the index value (Higher index value means 1). Table 7.6 Cost Effectiveness

Name of the River Estimated Cost (Crore Tk) Index Turag 1 12.01 Tongi Khal 1 12.01 Balu 3 18.55 Buriganga 5 20.05 Sitalakhya 2 18.27 Dhaleshwari 4 19.39 Padma 25.61 7 Meghna 6 23.38

7.6 Overall Index of the Surface Water Sources

Considering all the index of the surface water sources (rivers) the weighted average index value of the rivers is obtained as shown in Table 7.8. It seen that the Tongi khal has the value of 8 which is not recommended for use as surface water source whereas the Sitalakhya river has got the value 1 which is considered as the most suitable surface water sources as per

175 present overall analysis. Table 7.7 Overall Index of all the Rivers

Rivers Availability Quality Cost Mean Index Index Effectiveness Index Turag 4 7 1 3 Tongi Khal 5 8 1 5 Balu 4 5 3 3 Buriganga 3 5 5 4 Sitalakhya 2 3 2 1 Dhaleshwari 1 4 4 2 Padma 1 1 7 2 Meghna 1 2 6 2

7.7 Evaluation of Water Availability versus Water Quality

It can be envisaged that the water availability and quality are always associated with each other. If more water available in the sources, then water quality remains good. Quality of water deteriorates at lower flow condition. In Figure 7.12 it can be seen that the Padma river has more flow of water and it is less polluted. Likewise other rivers have the same interpretation.

9 Index: 1=Best; 8=Lowest 8 7 Water Avaiability 6 Quality

Index 4 3 2 1 0

Figure 7.12: Water availability and quality

7.8 Evaluation of Water Availability versus Cost Effectiveness

Figure 7.13 refers the the water availability index versus the cost effectiveness. It can be seen cost effectiveness of water supply becomes high when the source is in a distant location and

176 vice versa. For example, both the Dhaleswari and Sitalakhya sources have the concurrent better index. However, for other sources good index does not exist.

9 Index: 1=Best; 8=Worst 8 7 Water Avaiability 6 Cost Effectiveness 5

4 3 Index 2 1 0

Figure 7.13 : Water availability and cost effectiveness

7.9 Suggested SWTPs to be Operational

The proposed ‘River Network Restoration Project’ will take around 5 years to rehabilitate the peripheral river system of Dhaka. Overall purpose of the project is to protect Buriganga- Turag- River system from pollution and to ensure navigation through the rivers round the year for preservation of natural environment of the city. It is also expected that by this time all tanneries will be shifted to Savar and pollution level of the rivers will come down to an acceptable limit. It is expected that by the year 2020, Saidabad Phase III SWTP will be operational and total 450MLD water will be available from the peripheral rivers. Infrastructural requirement and expected water availability from peripheral rivers are given at Table 7.8.

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Table 7.8: Estimated Water Availability from Peripheral Rivers

Year 2017 2020 2025 2030 2035 Remarks Saidabad SWTP Phase I 225 225 225 225 225 Existing Saidabad SWTP Phase II 225 225 225 225 225 Existing Proposed SWTP III from Ongoing - 450 450 450 450 Sitalakhya Proposed SWTP IV from Suggested 39 39 450 450 450 Buriganga (present study) Proposed SWTP V from Suggested 450 450 Buriganga (present study) Proposed SWTP VI from Suggested 450 Buriganga (present study) Narayanganj SWTP 40 40 40 40 40 Existing Sonakanda SWTP 12 12 12 12 12 Existing Total (MLD) 541 991 1402 1852 2302 7.9.1 Utilization of Large Rivers

The Padma and Meghna Rivers should be incorporated into the water supply system after making optimum use of peripheral rivers. River Padma should get priority among these two rivers due to better quality and more availability of water. Water extraction from these two sources should be augmented gradually with increase of overall demand. Suggested utilization plan of large rivers including time by which SWTPs should be operational are given at Table 7.9. Table 7.9 : Ongoing Water Utilization Plan of Large Rivers

Year 2017 2020 2025 2030 2035 Padma SWTP Phase I - 500 500 500 500 Meghna SWTP Phase I - 500 500 500 500 Padma SWTP Phase II - - - 500 500 Meghna SWTP Phase II - - - 500 500 Total (MLD) - 1000 1000 2000 2000

Water demand and future requirement has been estimated 5105 MLD as detailed in Chapter 4 (Table 4.5). Table 7.10 shows an estimation of suggested withdrawal plan upto 2035. After assessment, it was found that 5402 MLD would be available to support the total requirement.

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Table 7.10: Suggested Plan for Future Water Production

Year Wise Production (MLD) Suggested Plan Source Remarks Oper. 2017 2020 2025 2030 2035 (months) Saidabad SWTP Phase I 225 225 225 225 225 Existing 12 Saidabad SWTP Phase II 225 225 225 225 225 Existing 12 SWTP III from Sitalakhya - 450 450 450 450 Ongoing 10 SWTP IV from Buriganga Suggested 6 39 39 450 1000 1000 (present study) SWTP V from Balu Suggested 6 450 450 (present

study) SWTP VI from Dhaleswari Suggested 12 1000 1000 (present

study) Narayanganj SWTP 40 40 40 40 40 Existing 6 Sonakanda SWTP 12 12 12 12 12 Existing 6 Padma SWTP Phase I - 500 500 500 500 Ongoing 12 Meghna SWTP Phase I - 500 500 500 500 Ongoing 12 Padma SWTP Phase II - - - 500 500 Ongoing 12 Meghna SWTP Phase II - - - 500 500 Ongoing 12 SW sources 12 Total Surface Water 2402 2402 2402 5402 5402 only from Sources (MLD) 2030 No GW Total Ground Water 1770 1250 1200 0 0 abstraction Sources (MLD) from 2030 Total (MLD) 4172 3652 3602 4902 5402 12

7.9.2 Paradigm Shifting towards Surface Water Sources

The production of surface water is increasing and dependency on ground water is considered zero with the timeline upto the year 2035. Therefore, a paradigm shift towards surface water sources can be seen in Figure 7.14.

179

5000

4000

3000

2000

1000 Production (MLD) Production 0

2015 2020 Year 2025 2030 2035 Required Prodution Surface Water Total Production

Figure 7.14: Shift towards surface water from ground water

7.10 Financial Plan

Monetary engrossments vary with the time of implementation. However, an approximate expenditure of the SWTP investment cost is given at Table 7.11. It is expected that, funds will be available from different friendly countries and donors for this type of projects. However, integrated planning by all agencies can make best utilization of all available resources.

Table 7.11: Year-wise Financial Requirement (Crore Taka)

Source Crore Year Wise Financial Requirement Tk/MLD (Crore Taka) production 2017 2020 2025 2030 2035 Restoration of Peripheral 4,000 river system Saidabad SWTP Phase III 11 5,000 Chadnighat SWTP Phase II 10 5,000 Padma SWTP Phase I 10 5,000 Meghna SWTP Phase I 10 5,000 Padma SWTP Phase II 10 5,000 Meghna SWTP Phase II 10 5,000 5,000 Total 9,000 15,000 10,000 5,000

7.11 Concluding Remarks

In this chapter, evaluation of cost effectiveness of sources has been made considering three criteria for all the selected surface water sources. These criteria were excess water

180 availability, quality parameter and cost estimation. Firstly, the availability of water was indexed based on allowable abstractable water. Secondly, the sources were indexed based on the quality parameter of the rivers. Then the cost evaluation was made depending on the distance and treatment of the sources. Finally, the overall evaluation was made using average of all the three index value. Evaluation reveals that the large rivers like Padma and Meghna and Sitalakhya, Dhaleswari rivers remain operational almost throughout the year. But the other peripheral rivers like Balu, Buriganga, Turag and Tongi remain unsuitable for almost six months. However, during the wet season these sources can be utilized and found to be cost effective.

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CHAPTER EIGHT CONCLUSIONS AND RECOMMANDATIONS

8.1 General

Water supply is very crucial due to increasing population growth in Dhaka city. Water requirement is increasing day by day. The present water supply system of Dhaka is heavily dependent on groundwater extraction. As the rate of groundwater recharge is not equal to the rate of extraction, there is a sharp decline of groundwater table. Present rapid depletion of groundwater only adds more disastrous consequence to these problems. All these conditions necessitate the requirements of exploring the options for suitable surface water sources for meeting the present and future demand of the city. In this study a comprehensive assessment has been made to explore the surface water availability for Dhaka city. Six peripheral rivers and two large rivers were selected for the analysis of surface water quality, water availability, water abstraction and cost effectiveness of the sources. If the selected surface water sources can be utilized fully, it will reduce the pressure on ground water. In previous chapters (Chapter 4 to Chapter 7), detail analyses with summary and concluding remarks were stated. In the following the specific conclusions and recommendations of this study have been outlined.

8.2 Conclusions

The conclusions from this study are outlined as follows: i. The Dhaka city has been expanded from the present area 404 sq km to about 617 sq km and continued to expand. Future population and associated water demand were assessed in details in Chapter 4. It was found that, every year the demand of fresh water is increasing by 5% approximately and water demand of 2017 will be doubled by 2035. The population trend was determined based on the BBS census data from 1975 to 2010 and prediction equation was formulated. During this period, the total population in the 617 sq km area is expected to increase 29 million by 2035. Water consumption in Dhaka city is showing an increasing trend. The total demand is expected to increase from about 1500 MLD in 2011 to 5100 MLD in 2035. Beyond 2035, there is likely to be around 50% increase in total demand by the year 2060.

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ii. Dhaka City is surrounded by six peripheral rivers including large rivers Padma and Meghna. Peripheral rivers system around Dhaka City includes Buriganga, Sitalakhya, Dhaleswari, Balu, Turag and Tongi Khal. Water quality of the peripheral rivers has been deteriorated severely due to increased pressure of various pollutants of urbanization and industrialization as described in Chapter 5. Water quality of peripheral rivers around Dhaka city was analysed with respect to pH, turbidity, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, ammonium, nitrate, phosphate, chromium, mercury, lead, Zinc etc. During the dry period (November to April) the water quality situation of the rivers Balu, Buriganga, Turag and Tongi khal becomes severely bad. Therefore, water cannot be abstracted in dry season for Tongi, Turag, Balu and Buriganga from peripheral rivers. However, the water quality parameters of these rivers appeared to be better during the wet season. Water can only be abstracted from Dhaleswari and Sitalakhya throughout the year. The water of Buriganga, Balu, Tongi khal and Turag remains beyond the standard limit in dry season. Water of these rivers remains unusable if such situation cannot be improved through treatment. The quality of Padma and Meghna remains good throughout the year. Thus the water from Padma, Meghna, Sitalakhya and Dhaleswari can be considered natural surface water source for Dhaka city water supply. iii. Hydrodynamic analyses have been carried out to determine the water availability of selected said rivers. The flow and water level hydrograph for the year 2006 to 2016 have been used. From the hydrographs, it can be seen that the lowest flow occurred in the dry season for peripheral rivers specially Turag and Tongi, but other rivers have sufficient water. In addition, detail hydrodynamic analysis has been carried out using mathematical model (HEC-RAS) for the river network of the peripheral rivers. The model result reveals that the water can be easily abstracted in the monsoon and post monsoon season for other rivers except Turag and Tongi Khal. iv. Impact of water abstraction on the environmental flow and on navigability has also been assessed. Using HEC RAS model, it was found that the water level, velocity and depth decreased due to the withdrawal of water from the peripheral rivers. Such impact of water abstraction is significantly true especially for dry season only. Outcome of the study focuses that the water remains sufficiently available for supply as source of surface water in monsoon season. The

183

Padma and Meghna always remain a potential source throughout the year. In dry season, Sitalakhya and Dhaleswari river can be utilized as a source of surface water. v. Evaluating few criteria such as availability of water, quality and cost estimate were examined in Chapter 7. The overall evaluation was made using mean average of all the four index value. Based on the evaluation index value, peripheral water sources scored more than the large rivers. The peripheral rivers are more cost effective than the large rivers as these are relatively nearer to Dhaka city. Thus it is quite clear that peripheral rivers should be given more importance than large rivers for future sources of supply perhaps proper restoration measures can be implemented. Restoration and rehabilitation of peripheral river system, protection of surface water from pollution, environmental conservation and river protection acts, relocation of tannery, including effluent treatment plants for all industries should be considered with due importance. vi. Suggested water withdrawal plan has been described in Chapter 7. As found from the study, the water demand in 2035 is likely to increase up to 5105 MLD. All this amount of water 100% demand can be fulfilled from the selected surface water sources. Suggested allowable limit of withdrawal can be 1000 MLD from Padma, 1000 MLD from Mehgna, 1000 MLD from Dhaleswari, 900 MLD from Sitalahkya, 1000 MLD from Buriganga, 450 from MLD Balu, 450 MLD from Turag and 180 MLD from Tongi khal. Infact , this suggested plan of water availability is the fully reverse of the existing scenario of ground water versus surface water. In this way, the surface water can be given high importance for sustainable and environment friendly water supply. vii. Finally, the author has focused few aspects on the financial aspects for evaluating the sources as well as the operational plan. Immediate restoration and rehabilitation of peripheral river system is obligatory for existence of the city. From the analysis and discussions, it was clearly understood that, suggested plan as shown in Table 7.10 makes optimum utilization of surface water to fulfil the future water requirement. It has been also found that in course of time the demand of the year 2017 would be doubled by the year 2035, but this plan can still sustain that requirement effectively. Thus, it can be concluded with the remarks that, river based surface water supply system both from large and peripheral rivers can effectively reduce the fresh water crisis of

184

the city ensuring viable environmental requirements. The peripheral rivers can be major water hub for future water supply for sustainable water environment of Dhaka city.

8.3 Recommendations for Future Study

This research opens up room for further studies: i. A study can be undertaken to find out the environmental issues to reduce the pollutant loading for clean surface water for Dhaka City. ii. Based on the outcome of the study, a feasibility and implementation plan can be undertaken of treatment plants of peripheral rivers. iii. For calculation of environmental flow wider options were considered which may be narrow down considering Bangladesh perspective and climate change. iv. To supplement the availability of surface water, a research may be conducted on other options of surface water sources such as rain water harvesting and use of grey water. v. To reduce the existing pollutants loads on the peripheral rivers, a comprehensive water quality modelling study can be undertaken. vi. Follow up study can be made with the newer set of data after 10 years with the change of situation. vii. Cost effectiveness was evaluated based on the location of the intake, quality of water and the availability. However, future study can be undertaken using optimization model. viii. In order to fulfil the suggested water requirement, further study can be undertaken for restoration and rehabilitation of peripheral river system. Social awareness and peoples’ participation could be major component of the study.

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