Study on Sustainability of Groundwater Resources in Rajshahi District of Bangladesh
Total Page:16
File Type:pdf, Size:1020Kb
STUDY ON SUSTAINABILITY OF GROUNDWATER RESOURCES IN RAJSHAHI DISTRICT OF BANGLADESH M. Sc. Engineering Thesis by Md. Ashraful Islam DEPARTMENT OF WATER RESOURCES ENGINEERING BANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY DHAKA-1000 OCTOBER, 2020 STUDY ON SUSTAINABILITY OF GROUNDWATER RESOURCES IN RAJSHAHI DISTRICT OF BANGLADESH A Thesis Submitted by Md. Ashraful Islam (Roll No. 1015162042P) In partial Fulfillment of the requirements for the Degree of MASTER OF SCIENCE IN WATER RESOURCES ENGINEERING DEPARTMENT OF WATER RESOURCES ENGINEERING BANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY DHAKA-1000 OCTOBER, 2020 i ACKNOWLEDGEMENT At first, the author acknowledges the blessing of almighty Allah for enabling him to complete the study successfully. The author is obliged to his thesis supervisor Dr. Umme Kulsum Navera, Professor, Department of Water Resources Engineering, BUET, for her continuous guidance, and caring and affectionate encouragement at every stage of this work. The author also expresses profound gratitude to his thesis committee member Dr. Anika Yunus, Professor and Head, DWRE, BUET, Dr. Md. Sabbir Mostafa Khan, Professor, DWRE, BUET and external member of thesis committee Dr. A.F.H. Afzal Hossain, Ex-DED (P&D), IWM for their nice and careful guidance and constructive suggestions during final thesis defense which have been immensely contributed to the improvement of this thesis. The author wishes his sincere gratitude to Mr. Mohammad Salah Uddin, Senior Specialist, Irrigation Management Division, IWM, Ms. Anin Dita Dey, Assistant Engineer, BWDB, Mr. S.M. Sahabuddin, Junior Specialist, IWM and Ms. Swarna Chowdhury, Junior Engineer, IWM for their continuous support and consultations regarding this research work. The author is grateful to IWM authority for giving supports by providing valuable guidance, necessary data, and permission to use software during this research work. The author is thankful to all the officials of WRE department and the authority for allowing him to use the WRE library. The author finally expresses his profound thanks to his parents for supporting and inspiring to conduct the M.Sc. in Water Resources Engineering at BUET. iv ABSTRACT Bangladesh is predominantly an agricultural country where agriculture sector plays a significant role in accelerating the economic growth of the country. It is therefore important to have a sustainable, environment-friendly and profitable agricultural system in order to ensure long-term food security. Agriculture in Bangladesh is largely dependent on groundwater resources. But this scarce groundwater resources have been decreasing alarmingly in Rajshahi district which is one of the most drought prone districts and driest place of Bangladesh. This situation has threatened the sustainability of agriculture in this area at present as well as in the near future. Over abstraction of groundwater, lack of surface water bodies, low rainfall, high elevation, thick clay layer are the major hindrances in the study area to sustain groundwater resources. As a result, groundwater level in this district is successively falling in each year. In this study it has been strived to sustain this valuable groundwater sources for the sustainable agriculture of this region. An integrated Surface Water- Groundwater base model from 2012 to 2016 has been developed, calibrated and validated. It has helped to understand current situation of the study area. In order to sustain groundwater resources up to year 2030, it is needed to foresee future condition of groundwater resources from 2017 to 2030. For this reason, there are ten (10) scenarios have been chosen to understand future groundwater condition in the study area by considering different driving forces such as Rainfall, Evaporation, Groundwater Level, Surface Water Level, and Water Demand. These scenarios have been analyzed to identify the most extreme future scenario that is needed to be countered by applying suitable interventions. Model output has been analyzed on eight Upazilas (Upazila wise) to understand the condition of groundwater precisely instead of taking study area as a whole. In spite of having different climatic conditions, soil type, cropping pattern, water demand and water availability most of these Upazilas have shown similar result. Scenario number 10 (S-10) has been found the most extreme scenario in most of the Upazilas (six out of eight). There are three interventions have been considered out of which intervention 1 (I-1) has shown significant result towards sustainable groundwater resources. In intervention 1, crop diversification technique has been applied by substituting high water consumed Boro rice by low water consumed Wheat and the outcome is v remarkable. Groundwater resources of 96.55% of the study area has improved and additional 3620 million cubic meter saturated zone is increased in the study area in the most extreme event (April, 2028) of most extreme scenario. Moreover, all analysis has been done to counter the driest event (April, 2028) of worst scenario so that reaming events could be could be countered. Based on analysis it can be said that this intervention will be a suitable solution to sustain groundwater resources for future in this area. The results that have been found from this study will be very much helpful to carry out further studies in future. vi TABLE OF CONTENTS ACKNOWLEDGEMENT iv ABSTRACT v TABLE OF CONTENTS vii LIST OF FIGURES x LIST OF TABLES xiii LIST OF ABBREVIATIONS xiv CHAPTER 1 INTRODUCTION 1.1 Background of the Study 1 1.2 Scope of the Study 2 1.3 Objectives of the Study 3 1.4 Organization of the Thesis 3 CHAPTER 2 LITERATURE REVIEW 2.1 General 5 2.2 Previous Studies and Researches on Groundwater 5 2.2.1 Groundwater Related Studies around the World 5 2.2.2 Groundwater Related Studies in Bangladesh 6 2.2.3 Groundwater Sustainability Related Studies in the North-West Region of Bangladesh 13 2.3 Groundwater and Sustainable Development Goals (SDGs) 15 2.4 Summary 16 CHAPTER 3 THEORY AND METHODOLOGY 3.1 General 17 3.2 Occurrence of Groundwater 18 3.3 Development of Groundwater Theories 18 3.4 Basic Theory of Modelling 20 3.5 Basic Theory and Equation of MIKE SHE 20 3.6 Basic Theory and Equation of MIKE 11 HD 24 3.7 Basic Theory of MIKE 11 NAM 26 vii 3.8 Methodology of the Study 27 3.8.1 Selection of the Study Area 28 3.8.2 Data Collection and Data Processing 28 3.8.3 Base Model Set Up 29 3.8.4 Calibration and Validation of Base Models 30 3.8.5 Selection of Design Year 30 3.8.6 Development of Scenarios 31 3.8.7 Prediction of Data Up to Year 2030 31 3.8.8 Result and Analysis 39 3.9 Summary 39 CHAPTER 4 STUDY AREA AND MODEL SET UP 4.1 General 40 4.2 Study Area 40 4.3 Hydrometeorology of the Study Area 44 4.4 Groundwater Model Set Up 55 4.5 Surface Water Model Set Up 62 4.6 Surface Water-Groundwater Interaction 64 4.7 Summary 65 CHAPTER 5 RESULTS AND DISCUSSIONS 5.1 General 66 5.2 Calibration and Validation of the SW and GW Model 66 5.2.1 Calibration and Validation of SW Model 66 5.2.2 Calibration and Validation of GW Model 67 5.3 Selection of Design Year for Scenario Development 69 5.4 Formulation of Future Scenarios 71 5.5 Determination of Most Extreme Scenario from Different Scenarios 74 5.6 Application of Interventions to Counter Extreme Scenario 89 5.6.1 Result from Non-Structural Intervention 90 5.6.2 Results from Structural Intervention 94 5.6.3 Result from Combined Intervention 95 viii 5.7 Depth of Phreatic Surface under Different Scenarios & Interventions 95 5.8 Results from Analysis 100 5.9 Meeting Goals of SDGs2030 106 5.10 Summary 108 CHAPTER 6 CONCLUSIONS AND RECOMMENDATIONS 6.1 General 109 6.2 Conclusions of the Study 109 6.3 Recommendations for Further Study 110 REFERENCES 111 APPENDIX-A APPENDIX-B APPENDIX-C APPENDIX-D APPENDIX-E ix LIST OF FIGURES Figure No. Title Page No. Figure 3.1: Hydrologic processes simulation by MIKE SHE hydrologic model 21 Figure 3.2: Schematic representation of the conceptual components in MIKE SHE hydrologic model 22 Figure 3.3: Flowchart of the Overall Methodology for the Study 27 Figure 3.4: Double mass curve for rainfall data under rainfall station, R170 in Durgapur Upazila for the year 2012 to 2016 29 Figure 3.5: Irrigation demands considered in the models (2017-2030) 34 Figure 4.1: Map of Study Area 40 Figure 4.2: Diagram of average monthly rainfall (Source: climate-data.org) 42 Figure 4.3: Diagram of average maximum and minimum temperature (Source: weather-atlas.com) 42 Figure 4.4: Topography of the study area 43 Figure 4.5: Generalized Tectonic Map of Bangladesh and Adjacent Area 44 Figure 4.6: Rainfall stations within/around the Rajshahi district 46 Figure 4.7: Selected Groundwater observation wells (Boundary Wells) under BWDB within/around the Rajshahi district 48 Figure 4.8: Selected Groundwater observation wells (Calibration Wells) under BWDB within/around the Rajshahi district 49 Figure 4.9: Yearly average trend of GWL at GT8125009 for the year 1974 to 2016 50 Figure 4.10: River water level hydrograph for river Ganges at Sardah station 51 Figure 4.11: Soil profile map of the study area (SRDI) 52 Figure 4.12: Plan of hydrostat graphic sections 53 Figure 4.13: Lithological cross section S2-N2 along South to North 53 Figure 4.14: Model area for MIKE SHE hydrologic model 56 Figure 4.15: Model domain and grid 57 Figure 4.16: Thiessen polygons for individual rainfall station in the study area 59 Figure 4.17: Initial groundwater level for the model on 1st January, 2012 61 x Figure 4.18: River network within model area in Mike