Numerical simulation for the assessment of groundwater safe yield in red river delta viet nam

1 ABSTRACTS In Red River Delta, there are many important economic regions located on the coastal areas The growth of both the economy and the population in these areas during the last decades, which is based on the availability of water resources, and the extensive exploitation have strongly increased the pressure on this finite and vulnerable resource Since surface water is unevenly distributed and increasingly affected by human activities, groundwater has become the major source of potable water This thesis therefore focused on contributing to the improvement of groundwater management in RRD by determining groundwater safe yield using modelling method Nam Dinh Province was selected to be the study area In the northern areas of Nam Dinh Province, due to the the high concentration of contamination in the groundwater aquifers, surface water is used as the main source of water for the region Groundwater usage in these areas is mainly for other purposes than domestic use Small scale groundwater extraction can be found near the main rivers with shallow wells in the uppermost aquifer due to the high level of contamination Deeper aquifers are the main subject for extensive extraction in the province Significant extractions are found in the south of Nam Dinh, where large freshwater lens in Pleistocene aquifer are located Therefore in this thesis, the Pleistocene aquifer is the main area of interest It was decided to use the Visual MODFLOW for the setting up of a numerical model of the Nam Dinh Area The 3D hydrogeological structure for the model was created from strata data of 83 boreholes, including 27 boreholes from Nam Dinh, 15 boreholes from Ha Nam, 17 boreholes from Ninh Binh, 23 boreholes from Thai Binh and from Thanh Hoa Natural neighbors method was used to interpolate the elevation of surface and bottom of the layers The 3D structural model was built with layers, representing aquifers and aquitard, including Upper Holocene aquifer (qh2), Lower Holocene aquifer (qh1), Pleistocene aquitard (qp2), Pleistocene aquifer (qp1) and Neogen aquifer (n) with the order from top to bottom respectively The finite difference grid used for the model has the size of 181 x 160 (181 columns x 160 rows, the size of each cell is approximate 400m x 400m) Observed water heads from 19 wells were used to calibrate and verify the model The normalize root mean squared of the calibrated model is 6.296%, which is considered to be good enough to simulate the future uses of groundwater for the study area To show the impacts of groundwater utilization on the qp aquifer in Nam Dinh Province, scenarios of future situations were simulated using the calibrated model Extraction rates were extrapolated until 2050 and three versions were considered: 1) Extraction rises constantly until 2050 in the same manner than from 1994 to 2012; 2) Extraction stays on a 2012 level, which means that no additional water is going to be extracted; 3) Extraction gradually declines to by 2050 The simulation results of these scenarios were used to estimate the groundwater safe yield for Nam Dinh Province It showed that the safe yield for the area is estimated to be 70300 m3/day DECLARATION I hereby certify that the work which is being presented in this thesis entitled, “Numerical simulation for the assessment of groundwater safe yield in Red River Delta, Viet Nam” in partial fulfillment of the requirement for the award of the Master of Science in Integrated Water Resource Management, is an authentic record of my own work carried out under supervision of Associate Professor Dr Vu Minh Cat and Dr Bui Du Duong The matter embodied in this thesis has not been submitted by me for the award of any other degrees or diplomas Date: 28th November 2014 ACKNOWLEDGEMENTS This thesis was completed at Faculty of Water Resources Engineering, Thuy Loi University First and foremost, I would like to thank my advisor, Assoc Prof Dr Vu Minh Cat for his invaluable guidance I am deeply grateful that I had the opportunity to learn from his knowledge I would like to thank Dr Bui Du Duong for his helpful contribution to the hydrogeology field and his supervision of my study I am very grateful to Assoc Prof Dr Pham Quy Nhan, MSc Dang Tran Trung and MSc Tran Thanh Le for their valuable advices and help with the preparation of spreadsheet data for the boreholes and well logs To Ms Mariette van Tilburg, I am very thankful for the English corrections, suggestions for my thesis and for providing me useful writing resources Lastly, a word of thanks is extended to NICHE-VNM-106 project team for providing a 18 months MSc scholarship Again, I would like to express my sincere gratitude for all these valuable help! TABLE OF CONTENTS ABSTRACTS DECLARATION ACKNOWLEDGEMENTS LIST OF ABBREVIATIONS LIST OF FIGURES LIST OF TABLES 11 CHAPTER I – INTRODUCTION 12 1.1 Background information 12 1.2 Objective & scope of study 14 1.3 Previous studies & state of knowledge 15 1.3.1 In the world 15 1.3.2 In Viet Nam 16 1.4 Methodology 18 1.5 Structure of thesis 20 CHAPTER II – CHARACTERISTICS OF NAM DINH PROVINCE 21 2.1 Physical settings of Nam Dinh Province 21 2.1.1 Geographical location 21 2.1.2 Topography 22 2.1.3 Climate conditions 22 2.1.4 Surface water bodies 24 2.1.5 Soils and land use 25 2.1.6 Population & Socio-Economy 26 2.1.7 Water supply and groundwater utilization 26 2.2 Geological characteristics of study area 28 2.2.1 Structural characteristics 28 2.2.2 Stratigraphy characteristics 32 2.3 Hydrogeological characteristics 2.3.1 Hydrogeological units 37 37 2.3.2 Groundwater dynamics 39 2.3.3 Groundwater salinity 42 CHAPTER III – CONSTRUCTION OF NUMERICAL MODEL TO ASSESS GROUNDWATER SAFE YIELD IN NAM DINH PROVINCE 44 3.1 Introduction of MODFLOW model 44 3.2 Model setup 47 3.2.1 Construction of 3D structural model 47 3.2.2 Model parameters 52 3.2.3 Boundaries conditions 54 3.2.4 Groundwater extraction 57 3.3 Model calibration 60 CHAPTER IV – SIMULATED RESULTS AND RECOMMENDATIONS 66 4.1 Scenario simulation 66 4.1.1 Extraction rises constantly 66 4.1.2 Extraction remains constant 67 4.1.3 Extraction gradually reduces 69 4.1.4 Estimation of groundwater safe yield 70 4.2 Discussion of model results 72 CONCLUSIONS AND RECOMMENDATIONS 74 REFERENCES 76 APPENDICES 78 LIST OF ABBREVIATIONS Generral abbreviations MONRE Ministry of Natural Resources and Environment NAWAPI National Center for Water Resources Planning and Investigation NDWRPI Northern Division of the National Center for Water Resources Planning and Investigation N, S, E, W North, South, East, West RRD Red River Delta UNICEF United Nations International Children’s Emergency Fund Technical abbraviations m bgl Meter below ground level m asl Meter above modern sea level TDS Total dissolved solids (mg/L) LIST OF FIGURES Figure 1.1: Steps of study 19 Figure 2.1: The outline map of Nam Dinh Province 21 Figure 2.2: Monthly averaged data for temperature, precipitation and potential evaporation in period from 1959 to 2007, measured at Van Ly station, coastal area of Nam Dinh 23 Figure 2.3: Land use distribution in Nam Dinh province, status 2007 25 Figure 2.4: Bar chart showing official data for communal and private water supply (ws) in Nam Dinh from 2005 to 2009 27 Figure 2.5: Quaternary geology and topography of the Red River delta and adjacent areas (Source: Tanabe et al 2006) 29 Figure 2.6: Geological Sketch map including major structural features and basis boundaries of the Holocene, Pleistocene and Neogene sediments (Source: NAWAPI) 30 Figure 2.7: Sketch map showing location (orange line) of typical hydrogeological cross section of Nam Dinh Province 31 Figure 2.8: Cross section from Vu Ban to Hai Hau (140x vertical exaggeration, modified after Hoc et al., 2003) 31 Figure 2.9: Time-series of monthly averaged Groundwater level of Holocene (qh), Pleistocene (qp) and Neogene (n) aquifers .41 Figure 2.10: Contour map of the hydraulic groundwater heads (m asl) in Pleistocene (qp1) aquifer in the Nam Dinh province in May 2010 (left) and November 2010 (right) (Source: NDWRPI) 41 Figure 2.11: Salinity distribution map (TDS) in qp pore water 43 Figure 3.1: Three-dimensional finite difference grid used in MODFLOW 45 Figure 3.2: Sketch map showing locations of boreholes used to construct the 3D structural model 48 Figure 3.3: Finite difference grid and extent border of the model 48 Figure 3.4: 3D hydrogeological structure of Nam Dinh Province 49 Figure 3.5: Sketch map showing bottom elevation contours of layers: a) Upper Holocene aquifer, b) Lower Holocene aquifer, c) Pleistocene aquitard, d) Pleistocene aquifer, e) Neogen aquifer .52 Figure 3.6: Hydraulic conductivity (m/day) for each aquifer: a) Upper Holocene, b) Lower Holocene, c) Upper Pleistocene, d) Lower Pleistocene, e) Neogene 53 Figure 3.7: Distribution of artificial well locations in study area .58 Figure 3.8: Estimated groundwater withdrawal rate from 1994 to 2009 in Nam Dinh Province .59 Figure 3.9: Sketch map showing the locations of groundwater monitoring wells in Nam Dinh Province 61 Figure 3.10: Calculated versus measured water heads in Q108, 109 and 110 62 Figure 3.11: Best fit simulation water level contour in qp aquifer (December 2012) 63 Figure 3.12: Calibration residuals histogram 63 Figure 3.13: Calculated versus measured water heads in Q221-Q229 from 2010 to 2012 64 Figure 3.14: Scattered plot showing the relation between calculated and observed head 65 Figure 4.1: Estimated groundwater level until 2050 at Q109 with a constant rise of extraction as postulated until 2012 66 Figure 4.2: Sketch map showing the groundwater level contour in qp aquifer in December 2050 with a constant rise of extraction as postulated until 2012 .67 Figure 4.3: Estimated groundwater level until 2050 at Q109 with a constant level of extraction as in 2012 68 Figure 4.4: Sketch map showing the groundwater level contour in qp aquifer in December 2050 with a constant level of extraction as 2012 68 Figure 4.5: Estimated groundwater level until 2050 at Q109 with a constant decline of extraction .69 10 Figure 4.6: Sketch map showing the groundwater level contour in qp aquifer in December 2050 with a constant decline of extraction 70 Figure 4.7: Estimated groundwater level until 2050 at Q109 in different scenario 72 71 acceptable In the case of Nam Dinh Province, the water head was selected to be the criteria for assessing the safe yield for qp aquifer As regulated by MONRE, the maximum drawdown of water head is regulated as -50m asl In the first pumping scenario, the maximum depth of water table is -40m, which is only 10m above the allowed depth of -50m; and the water level keeps declining at a rate of nearly 0.8m/year This pumping scenario was not taken into account in the estimation of safe yield In the second scenario, the maximum depth of water level is -14m asl by the end of 2050 and the reduction rate tends to reduce over time This value is by far to pass the allowed depth of -50m asl and seemed to be “acceptable consequences” for groundwater exploitation in the next 35 years However, the development of the depression cone in the freshwater zone can cause the brackish water to move southward, which can greatly affect the groundwater usage in Xuan Truong, Truc Ninh, Giao Thuy and Nam Truc districts Therefore, the safe yield for the qp aquifer in the study area is expected to be the maximum pumping rate that not lead to the futher development of the extraction cone in the region The results from the second and the third scenario were used as a range which helps to reduce the amounts of pumping variations Various pumping variations were run to determine the safe yield for Nam Dinh area The safe pumping rate for each district is shown in Table 4.1 Table 4.1: Estimated safe pumping rate in Nam Dinh Province District Giao Hai Nghia Nam Truc Xuan Thuy Hau Hung Truc Ninh Truong 27727 24848 2276 8098 4256 Total Safe pumping rate (m3/day) 3095 70300 72 Figure 4.7 shows the water head in Q109 in scenarios compare to “safe yield” results Water level (m asl) -5 -10 -15 Constant rise -20 Constant -25 Constant decline -30 Safe -35 Nov-48 Sep-45 Jul-42 May-39 Mar-36 Jan-33 Nov-29 Sep-26 Jul-23 May-20 Mar-17 Jan-14 Nov-10 Jul-04 Sep-07 May-01 Mar-98 Jan-95 -40 Time Figure 4.7: Estimated groundwater level until 2050 at Q109 in different scenario It should be noted that to cope with the lack of data, several assumptions were made to help the constructing of the numerical model The current model can not fully present the actual behaviors of aquifers in the study area due to the uncertainties The estimated safe yield of 70300 m3/day is a very rough value Futher research as well as refinement of the model should be conducted to investigate the actual interaction of the ground-surface water resources to determine a more reliable result 4.2 Discussion of model results The 3D structural model and GIS software help to comprise information of various sources Map data of different origins and scales as well as tabular information or cross sections can be used to support the construction of cross sections within the 3D environment The advantage of such a system is that inconsistencies in data are more clearly identified than with other media types like 73 2D cross sections Due to the limitation of time, the refinement of such 3D models is a task for long term assignment The results of the numerical model simulation fairly well match observations However, calculation errors can not be avoided As mentioned in Section 3.3, the model overestimated the water level in Q221 and Q222 As a small freshwater len in qp aquifer exist beneath the city of Nam Dinh (Figure 2.11), groundwater extraction is possible in the city and adjacent areas During the construction of the model, extraction in qp aquifer in the north of Nam Dinh was assumed to be insignificant and was not taken into account This can be the main reason for higher calculated water heads in Q221 and Q222, which are located near Nam Dinh city It is suggested that the water extraction of water wells is still too uncertain for the current model to be able to simulate scenarios with great details precisely Therefore only a few simple future scenarios were set up and simulated However, the simulation results of these scenarios still help to visualize how groundwater would change corresponding to different pumping schemes It is also suggested that model results would greatly improve when extraction from qp and n aquifers are further quantified It is also especially necessary to estimate aquitard parameters and associated specific storage values for all hydrogeological units The freshwater zone in qp aquifer is surrounded by brackish water The development of extraction cone in the center of this zone could possibly lead to saline water instrusion The extension of current model to transport and density flow modelling would be a further step to understand the salinity-freshwater complex With the current settings it would be possible to switch to density flow modelling with SEAWAT to improve the ocean boundary settings 74 CONCLUSIONS AND RECOMMENDATIONS Conclusions The geological in the study area is very complex A 3D structural model combine with GIS software and proper data can help to handle this Five main hydrogeological units can be distinguished in this area, namely: Upper Holocene aquifer (qh2), Lower Holocene aquifer (qh1), Upper Pleistocene aquitard (qp2), Lower and Middle Pleistocene aquifer (qp1) and Neogene aquifer (n) The hydraulic connection between the qp and the above aquifers is very small The higher water heads in neogen aquifer indicates the potential leakage from n aquifer to qp aquifer The qp aquifer is considered to be very water-rich in both terms of quality and quantity In this aquifer, the freshwater zone in the south of Nam Dinh is the main object of extensive extraction Since it is surrounded by brackish water, saline water intrusion is possible in the future In this study, MODFLOW model was sucessfully implemented to simulate the groundwater flow in Nam Dinh Province The results are well match with the observations This provides the basis for simulating the groundwater uses in the future The safe yield for the qp aquifer in Nam Dinh province is estimated to be around 70300 m3/day This is only 70% of current extraction rate in 2012 Recommendations  The distribution of freshwater lens of outer continental shelf in surface area and depth should be studied More detailed hydrogeological investigation and application of geophysical methods in hydrogeology are recommended;  A refinement of the model with further improvement of historical input data is is necessary to help improve the model results: An integration of Ninh Binh hydrogeology for groundwater structure and recharge assessment is required to model groundwater recharge correctly Aquitard parameters and associated specific storage values needs to be identified, aquifer parameters 75 need to be improved in quantity and quality Amount, position and extraction rate of pumping wells needs to be quantified  The management of groundwater exploitation in the Nam Dinh area should be appropriate considered A good planning and reasonable utilization groundwater resource will improve using of valuable source of freshwater in the region 76 REFERENCES [1] Barthel, R., Braun, J., Rojanschi, V., & Wolf, J (2004) Modelling Groundwater Flow on the Regional Scale in the Upper Danube Catchment (Germany) Groundwater Flow Understanding – From Local to Regional Scales, International Association of Hydrogeologists, 8-11 [2] Canh, D.V., Lai, L.T., Hung, H.V., Roi, N.D., & Nghia, N.V (2005) Groundwater resource of Nam Dinh Province Journal of Geology, Series B, 25, 31-42 [3] Cu, N.V., Huan, N.V., Lan, V.Q., & Thang, V.N (1996) Report on Geology and Minerals, Group of Thai Binh - Nam Dinh sheets, scale 1:50.000 (19931995), Vol 1: Geology DOG Department of Geology, 217; Hanoi (in Vietnamese) [4] Dan, N.V (2009) Study on Hydrogeological conditions and current exploitation of groundwater in coastal zone of Nam Dinh province Northern Division for water resources planning and investigation (in Vietnamese) [5] Datta, B., Vennalakanti, H., & Dhar, A (2009) Modeling and control of saltwater intrusion in a coastal aquifer of Andhra Pradesh, India Journal of Hydro-environment Research 3, 148-159 [6] Do, N.V (1996): Report on hydrogeological mapping at a scale 1:50.000 in Nam Dinh area Department of Geology, Hanoi (in Vietnamese) [7] Duong, B.D., Kawamura, A., Thanh, T.N., Amaguchi, H., Nagakawa, N., & Iseri, Y (2011) Identification of aquifer system in the whole Red River Delta, Vietnam Geosciences Journal, 15 (3), 323 – 338 [8] Erban, L.E., Gorelicka, S.M., Zebkerb, H.A., & Fendorfa, S (2013) Release of arsenic to deep groundwater in the Mekong Delta, Vietnam, linked to pumping-induced land subsidence PNAS Early Edition Available at: www.pnas.org/cgi/doi/10.1073/pnas.1300503110 [9] Henriksen, H.J., Troldborg, L., Nyegaard, P., Sonnenborg, T.O., Refsgaard, J.C., & Madsen, B (2003) Methodology for construction, calibration and 77 validation of a national hydrological model for Denmark Journal of Hydrology 280 (1–4), 52–71 [10] Hoc, B.; Lai, L.T., Schafmeeister,M.T., Huy, P.K., & Binh, D.V (2003) Application of isotopic hydrogeological methods to investigate groundwater in Nam Dinh area Journal of Geology, Series B, 21, 88-94, 65 [11] Kresic, N (2007) Hydrogeology and Groundwater Modeling - Second Edition Taylor & Francis Group, LLC [12] Mende, A., Astorga, A., & Neumann, D (2007) Strategy for groundwater management in developing countries: A case study in northern Costa Rica Journal of Hydrology, 334, 109–124 [13] Minh, T.V (2004) Mathematical modeling for groundwater abstraction in coastal areas Ph.D thesis, Da Nang University, Da Nang, 134 p (in Vietnamese) [14] MONRE (2013) Report on groundwater resources in 2012 and forecasting groundwater trend from June to September 2013 Ministry of Natural Resources and Enviroment, Vietnam (in Vietnamese) [15] Postma, D., Larsen, F., Hue, N.T.M., Duc, M.T., Viet, P.H., Nhan, P.Q., et al (2007) Arsenic in groundwater of the Red River floodplain, Vietnam: Controlling geochemical processes and reactive transport modelling Geochim et Cosmochim Acta 71, 5054–5071 [16] Tanabe, S., Saito, Y., Lan, V.Q., Hanebuth, T.J.J., Lan, N.Q., & Kitamura, A (2006) Holocene evolution of the Song Hong (Red River) delta system, northern Vietnam Sedimentary Geology, 187, 29-61 [17] Thomsen, R., Sondergaard, V.H & Sorensen, K.I (2004) Hydrogeological mapping as a basis for establishing site-specific groundwater protection zones in Denmark Hydrogeology Journal 12, 550-562 [18] Zhou, Y (2009) A critical review of groundwater budget myth, safe yield and sustainability Journal of Hydrology 370 (1-4), 207-213 78 APPENDICES 79 Appendix 1: Monitored TDS values in Nam Dinh Province in 1999-2000 No X Y pH Na K Ca Mg ΣFe 18616877 2240551 8.4 488.97 6.94 108.22 93.63 17.77 18626084 2234162 8.3 39.04 0.78 19.04 13.98 0.7 18635172 2227984 43.84 0.52 44.08 19.46 5.59 18606432.6 2237475.2 7.1 146.3 10.6 142 40.8 1.09 18613803.2 2236277.2 7.8 42.9 6.1 16 13.8 18618979.7 2235162.4 7.6 37 4.8 25 18618208.3 2231122.3 7.9 55.6 5.6 18617280.8 2225630.2 7.8 87.8 18615311.5 2224666.8 7.8 10 18614030.8 2222466.2 11 18619447.6 12 Al NH4 HCO3 SO4 Cl PO4 NO3 NO2 F 36.5 73.22 48.03 1206.65 205.94 9.41 13.11 0.64 286.79 13.59 39 0.06 0.01 427 30 380.4 0.48 2.09 8.2 0.38 1189.41 0.46 1.12 0.01 210.5 0.5 25 1.36 5.73 0.01 0.57 324.05 17.4 1.22 0.04 0.01 214.5 0.5 35.5 1.19 1.55 0.01 0.54 339.25 21 14.4 0.18 0.04 0.01 232 0.5 46.15 1.07 2.71 0.01 0.51 379.76 27.5 18.3 0.86 0.04 0.01 241.6 0.5 124.3 0.85 6.51 0.01 0.54 515.81 101.4 12.8 74 78 2.1 0.02 0.01 213.5 0.5 447.8 0.7 2.4 0.01 0.32 933.55 7.6 329.7 7.3 56 28.8 0.13 0.02 0.01 478.5 0.5 491.7 0.52 2.43 1.5 0.59 1397.7 2221691.1 7.6 37.1 6.2 37.5 25.5 2.4 0.08 0.01 226.2 78.1 0.78 2.2 0.01 0.46 417.53 18612608.3 2214506.1 198 7.7 5.4 0.4 0.06 0.01 446.75 8.6 104 1.13 6.66 0.01 1.07 788.78 13 18607526.7 2241299.1 7.7 120.1 5.9 21 7.5 1.2 0.03 0.01 220 0.5 131.35 0.5 2.17 13.6 0.95 524.8 14 18611039.6 2238105.2 7.8 79.5 4.5 12 0.3 0.03 0.01 236.7 0.5 17.5 0.56 18.95 1.28 1.37 376.19 15 18610698.3 2243846.4 7.7 61.4 4.7 4.2 0.2 0.04 0.01 165 10 17.5 0.5 5.86 6.6 1.79 283.79 16 18608877.4 2246635.3 7.4 95.6 12.2 50 55.2 3.8 0.04 1.4 163.85 341.5 0.56 3.33 10.55 0.35 739.38 17 18605379.8 2245297.9 7.3 157 15.8 152 91.8 2.2 0.04 7.5 207.85 171 598.5 0.22 23.25 16.8 0.35 1444.31 18 18635493.9 2244047.3 7.2 91.7 9.8 56 48 6.2 0.03 24 289.75 0.5 269.25 0.54 0.1 1.24 0.23 797.34 0.04 TDS 2079.97 3.85 305.85 0.78 454.29 80 19 18633833.5 2241213.7 7.6 43.9 6.1 25 16.8 0.19 0.03 0.01 256.65 0.5 25 0.59 4.96 3.4 0.54 383.66 20 18636323.7 2248664.2 7.2 593.4 17.6 173 79.8 13.83 0.03 15.5 154.3 0.5 1568 0.65 0.21 0.1 0.46 2617.38 21 18644978.2 2248947 7.2 1796.7 83.2 270 222 19 0.03 74 122 0.5 4415.8 0.82 0.01 0.04 0.21 7004.31 22 18645234.5 2244536.8 7.2 627.9 23.5 172 92.4 26 0.03 27 216.55 0.5 1429.5 1.19 0.01 0.68 0.06 2617.32 23 18643005.4 2243029.9 472.2 13.9 124 76.8 33 0.03 11.75 122 0.5 1234 0.74 0.01 0.01 0.18 2089.11 24 18638604.7 2240910.9 7.5 42.9 6.8 26 21.9 1.2 0.02 2.25 248.5 0.5 56.8 1.19 0.01 0.01 0.51 408.58 25 18638225.8 2233872.6 7.6 41.9 5.1 20 15.6 0.7 0.02 0.01 224.4 7.2 21.3 1.34 2.17 1.42 0.54 341.7 26 18641102.6 2234291.2 7.6 46.8 6.2 30 22.8 1.08 0.03 0.01 279.2 12 42.5 1.08 2.48 0.01 0.4 444.58 27 18643376 2234586.1 7.6 56.5 6.4 30 21 0.87 0.03 0.01 311.65 2.2 35.5 1.19 10.07 0.01 0.54 475.96 28 18647945.2 2240283 7.3 455.5 17.8 100 69.6 3.3 0.03 17.5 275.2 0.5 1057 1.76 0.01 0.43 0.1 1998.72 29 18650449.9 2237817.8 7.5 259.5 13.6 70 55.2 0.06 0.04 393.45 0.5 477 0.56 1.86 2.2 0.54 1279.51 30 18652576.1 2239999.7 6.9 1183.3 60.3 133 118.2 13.5 0.06 29 423.15 0.5 2563.25 0.77 0.03 0.37 4526.43 31 18655104.9 2242164.7 7.1 1689.6 81.7 280 252 11.5 0.05 29 201.3 0.5 4166.5 0.43 0.46 8.6 0.13 6721.77 32 18658100 2242300 7.3 2613.4 160.2 154 303.6 0.74 0.03 88.5 519.65 0.5 5695.5 3.31 0.77 5.16 0.56 9545.92 33 18660700 2243400 7.1 1638.8 65.8 201 161.4 5.5 0.03 21.5 347.7 0.5 3572.5 0.33 0.46 0.1 0.23 6015.85 34 18659100 2245100 7.3 3520.9 206.5 160 374.4 4.55 0.06 20 841.5 0.5 7197 3.01 0.79 1.24 0.43 12330.88 35 18640887.9 2238284.3 7.7 55.6 42 32.4 0.25 0.04 3.2 312.85 0.5 100 1.13 0.01 0.17 0.7 555.84 36 18636221.8 2237256.4 7.6 31.2 6.2 40 22.8 0.59 0.04 0.01 257.5 0.5 42.6 1.08 0.01 0.01 0.56 403.08 37 18626917.7 2214869.4 7.6 58.5 5.9 26 15.6 1.13 0.04 0.01 278.15 0.5 39 0.93 4.96 0.01 0.27 430.99 38 18623546.1 2217945.1 7.6 36.1 5.8 34 25.8 1.63 0.06 0.01 259.25 0.5 50.2 1.41 2.32 0.01 0.59 417.67 81 39 18619844.5 2217381.3 7.7 22.4 4.6 30 20.4 0.42 0.07 0.01 111.8 0.5 79.88 0.74 1.08 0.01 0.5 272.39 40 18618185.5 2213950.8 7.6 37 5.3 23 15.6 0.95 0.04 0.01 207.95 0.5 32 0.67 2.01 0.01 0.43 325.46 41 18620084.4 2211897.8 7.7 104.4 7.3 27 12 0.53 0.04 0.01 367.5 0.5 53.3 0.65 4.18 0.01 0.64 578.05 42 18622249.1 2214576.8 7.7 92.2 20 7.4 1.12 0.04 0.01 228.75 0.5 48.5 0.56 1.7 0.01 0.27 406.05 43 18625855.2 2219591.7 7.9 34.5 4.4 28 19.2 0.16 0.06 1.9 259.8 0.5 24.85 1.11 0.54 1.9 0.54 377.46 44 18623221.6 2224660.2 7.8 51 5.6 20 21.6 0.18 0.05 0.01 234.85 0.5 53.3 1.11 3.56 0.01 0.67 392.43 45 18630562 2220480.8 7.6 46.4 5.3 26 18.6 0.32 0.03 0.01 265.35 0.5 34.5 1.08 3.25 0.01 0.56 401.9 46 18633491 2223344.3 7.6 41.3 5.1 23 15.6 0.42 0.08 0.01 233.2 0.5 24.8 1.08 2.86 0.01 0.67 348.62 47 18621395.6 2263005.6 7.3 577.2 14.5 172 94.8 40 0.06 45 152.5 0.5 1686.25 0.43 0.46 0.16 0.07 2783.93 48 18647358.3 2267281.3 6.5 237.8 10.1 94 15.2 12 0.02 1.92 94.8 566.25 2.46 0.15 0.04 0.05 1035.79 49 18604934.5 2262007.2 7.1 767.1 34.5 124 141.6 16 0.04 0.01 152.2 0.5 1949.5 0.33 0.62 0.31 0.37 3187.08 50 18624127.9 2236457.2 7.3 35.1 5.3 16 16.8 0.33 0.11 0.01 208.75 0.5 14 1.41 6.2 6.8 0.5 311.81 51 18623053.4 2232767.6 7.2 48.9 5.9 54 46.8 0.3 0.11 0.75 175.25 0.5 234.3 0.74 1.62 3.35 0.43 572.95 52 18620522 2237399.6 7.2 42.8 22 13.8 0.11 0.08 0.35 219.8 0.5 28.4 1.34 0.23 3.5 0.62 338.53 53 18618528.3 2237703 42.6 4.5 21 15.6 0.5 0.04 0.02 213.5 0.5 39.1 1.49 2.24 0.01 0.59 341.68 54 18615303.7 2238971.2 7.2 34.5 5.5 20 13.2 0.78 0.04 0.01 177.35 0.5 32 1.23 3.87 0.01 0.54 289.52 55 18617732.8 2240857.2 6.9 41.4 4.9 19 12 0.94 0.04 0.01 181.3 0.5 32 1.56 3.56 0.01 0.54 297.75 56 18619788.1 2240156.8 6.9 34.4 5.7 19 19.8 1.9 0.04 0.01 213.5 0.5 35.5 1.19 4.03 3.25 0.07 338.89 57 18620397.5 2244493.8 7.1 60.8 7.6 44 40.2 1.95 0.06 3.9 248.55 0.5 177.5 0.56 0.15 3.55 0.29 589.61 58 18625730.4 2244736.7 6.8 297.1 12.6 171 110.4 5.3 0.07 4.65 152.5 0.5 1121.75 0.43 0.35 0.01 0.56 1877.21 82 59 18630036.6 2245041.5 176.5 8.2 108 45.6 22.5 0.08 34 225.7 0.5 617.7 0.56 1.08 12.8 0.54 1253.76 60 18630691.6 2241806.8 6.9 130.4 44 32.4 3.7 0.06 26.5 253.15 0.5 298.2 0.71 0.46 2.7 0.37 800.15 61 18623955.6 2239809.7 73.3 8.1 50 43.2 0.11 0.04 331.8 0.5 166.85 0.43 0.38 0.2 0.4 678.31 62 18626591.8 2233966.2 27.2 4.7 23 15.6 0.32 0.06 0.01 213.5 0.5 14.2 1.11 2.86 0.01 0.62 303.68 63 18624520 2231080 7.1 36.3 4.2 29 15 0.31 0.04 0.01 203.75 0.5 35.5 1.13 2.17 0.01 0.54 328.45 64 18632092.6 2238160.2 47.9 5.3 22 13.2 0.1 0.06 0.01 232.7 0.5 21.3 1.58 3.29 5.35 0.76 354.05 65 18630976.9 2234758.5 42 5.1 18 15.6 0.19 0.07 0.01 236.25 0.5 17.5 1.24 4.1 0.03 0.78 341.36 66 18628572.6 2231516.3 6.5 41.1 7.5 18 15.6 0.03 0.01 0.01 243.3 0.5 12.3 0.74 8.52 0.02 0.73 348.35 67 18627738.9 2228032.2 58.9 4.9 16 10.8 0.37 0.01 0.01 251.5 0.5 17.5 1.34 3.33 0.01 0.7 365.86 68 18627371.8 2223478.3 6.5 40.4 5.7 20 19.2 0.42 0.01 3.25 238.1 0.5 31.95 0.59 3.79 0.01 0.54 364.45 69 18630422.6 2226024.7 37.5 5.6 27 21.6 0.31 0.08 0.01 286.7 1.8 17.5 0.59 4.49 0.01 0.59 403.77 70 18631177.3 2229051.1 6.5 61.7 6.1 18.5 12.6 0.16 0.06 1.92 278.2 0.5 14.2 1.41 5.96 6.5 0.73 408.54 71 18633582.3 2226127.3 30.2 4.2 30 16.8 0.98 0.05 0.01 216.7 0.5 35.5 0.46 1.08 0.01 0.24 336.72 72 18639406.8 2229826.9 57.8 4.8 22 18 1.52 0.08 0.01 278.9 31 15 0.56 1.31 0.01 0.37 431.35 73 18631784.7 2227982.3 6.5 42.4 5.2 29 18 0.06 0.07 0.01 255.75 15 21 0.44 4.26 0.01 0.59 391.78 74 18633932 2229866.3 6.5 30.2 4.4 31 18 0.29 0.1 0.01 241.1 21 0.44 1.62 0.01 0.59 356.75 75 18635366.4 2234249.1 51.5 5.2 23 14.4 0.22 0.08 0.01 274.5 12.2 1.52 0.54 0.01 0.7 392.87 76 18621839.4 2260408.3 6.5 200.1 6.7 128 48 18 0.08 27.5 162.2 0.5 678.5 0.93 1.47 8.5 0.21 1280.69 77 18612622.3 2267098.4 6.5 228.1 11.4 196 79.2 23.75 0.08 42 404.7 0.5 877.7 0.96 1.31 21 0.43 1887.13 78 18611261.8 2264783.3 165 7.7 148 57.6 3.45 0.08 21.5 232.35 0.5 614 0.59 2.63 56 0.43 1309.83 83 79 18627518.9 2255996 7.4 532.9 11.9 240 92.4 23.5 0.04 49.5 128.1 0.5 1612.75 0.7 0.01 20 0.05 2712.35 80 18630110.9 2255143.8 7.4 1306.2 43.2 265 153 44.5 0.07 1.3 189.1 3185 0.93 0.01 0.04 0.32 5189.67 81 18622353.7 2244478.1 112 9.24 40 34.2 0.54 0.02 2.42 277 173 1.5 0.01 13.25 0.26 664.45 82 18599000 2254200 560 18.3 260 209 23.4 0.11 1.2 126.75 1.28 2009.9 0.23 9.2 0.37 3220.74 83 18613964.7 2254258.1 261.9 8.13 106 44.4 21 0.01 108 337.5 3.2 779.9 0.66 0.15 36.5 0.37 1707.72 84 18636131.4 2234195.1 42 3.99 18 14 0.04 0.28 0.45 232.3 6.64 9.64 2.93 0.54 0.04 0.47 331.32 85 18644428.6 2256906.2 7647.4 300.8 110 99.6 6.25 0.68 182.5 1082.8 4.68 12580.7 3.12 0.77 0.29 0.53 22020.12 86 18616877 2240551 7.1 622.22 6.98 102.2 98.5 16.77 48 100.68 4.8 1474.72 87 18626084 2234162 7.8 50.21 0.78 20.04 15.81 4.19 219.67 11.41 26.59 88 18635172 2227984 7.5 45.38 0.55 46.08 22.46 4.19 0.94 290.59 16.59 41 89 18606432.6 2237475.2 7.4 165.21 9.29 156 38.4 1.08 0.08 0.14 411.75 19.32 453.76 0.1 0.93 6.2 0.37 1262.26 90 18615311.5 2224666.8 7.1 128.29 12.37 76 76.8 1.74 0.12 0.28 207.4 478.58 0.1 0.54 0.04 0.36 983.26 91 18614030.8 2222466.2 7.2 368 5.19 60 28.8 0.44 0.12 0.25 506.3 537.2 0.1 0.69 0.06 0.49 1508.15 92 18612608.3 2214506.1 7.7 226.2 6.08 5.4 0.37 0.18 0.24 496.65 9.38 124.07 0.57 1.47 0.03 0.68 879.63 93 18607526.7 2241299.1 7.3 249.32 3.98 20 10.8 0.54 0.14 0.09 381.25 211.8 0.33 18.8 0.65 899.05 94 18611039.6 2238105.2 7.5 89.19 3.06 12 3.6 0.29 0.05 0.09 244 15.95 0.99 20.15 0.27 0.85 390.64 95 18608877.4 2246635.3 6.8 113.05 11.45 46 54 3.05 0.16 0.09 152.5 356.81 0.21 7.9 5.5 0.41 751.72 96 18635393.9 2244047.3 108.44 8.74 52 44.4 9.8 0.2 22.5 344.65 253.46 0.21 0.46 8.6 0.39 854.46 97 18647945.2 2240283 6.5 503.05 14.72 100 72 2.25 0.09 21 285 1155.3 0.15 0.31 0.1 0.29 2154.96 98 18646000 2234600 6.8 208.42 8.69 40 33.6 0.1 0.1 0.09 366 7.03 264.1 0.75 6.51 0.07 0.54 935.46 0.11 2474.98 4.9 353.6 1.02 468.8 84 99 18655104.9 2242164.7 6.6 1701.02 36.59 272 253.2 23.5 0.11 17.75 198.25 4180.8 0.15 0.23 4.5 0.36 6689.1 100 18640887.9 2238284.3 6.7 80.23 6.13 44 38.4 2.3 0.16 0.09 344.65 106.35 0.66 1.78 0.47 633.74 101 18623546.1 2217945.1 7.2 49.09 6.31 24.8 25.92 1.76 0.07 0.09 286.7 42.54 0.63 0.93 3.1 0.5 442.94 102 18620084.4 2211897.8 7.3 110.15 5.62 23 9.6 1.16 0.11 0.14 369.3 35.45 1.38 5.19 0.09 0.54 562.19 103 18623997.8 2221267.4 7.4 46.54 5.26 32 34.8 1.3 0.07 0.13 228.75 120.53 0.33 2.71 0.04 0.44 473.46 104 18630562 2220480.8 6.7 48.52 4.36 28 19.2 0.12 0.08 0.01 268.4 35.45 0.78 0.01 0.06 0.46 405.99 105 18647358.3 2267281.3 6.4 239.34 10.36 96 84 23.75 0.1 2.43 97.6 850.8 0.27 0.23 0.03 0.23 1405.91 106 18644319.3 2262715.3 7.5 1547.39 81.96 66 164.4 0.01 0.13 11.12 112.85 27.4 3190.5 0.12 0.01 9.2 0.43 5211.09 107 18622788.7 2227697.8 7.1 48.66 3.68 24 14.4 1.1 0.11 1.05 234.1 42.54 0.6 0.23 0.22 0.42 371.69 108 18608713.7 2263176.5 6.3 307.59 12.95 144 72 12 0.08 116 616.1 930.56 0.33 0.46 0.1 0.44 2213.17 109 18624127.9 2236457.2 6.6 44.63 4.58 18 4.08 1.2 0.12 0.09 189.6 14.18 2.22 2.01 0.12 0.63 281.82 110 18619788.1 2240156.8 6.6 42.84 5.05 22 17.6 1.74 0.24 0.13 210.45 38.99 1.23 3.72 0.08 0.54 345.06 111 18620397.5 2244493.8 6.8 79.84 7.49 37 56.4 3.4 0.32 0.25 256.2 184.34 0.18 1.47 0.1 0.42 627.99 112 18625730.4 2244736.7 6.8 297.01 11.71 171 114 8.5 0.18 6.75 152.5 1133.3 0.1 0.01 0.08 0.34 1896.14 113 18623955.6 2239809.7 6.8 109.9 8.54 52 49.2 2.15 0.08 0.09 350.75 212.7 0.51 4.49 10.4 0.44 801.81 114 18632092.6 2238160.2 6.7 65.76 4.55 22 14.4 1.25 0.14 0.01 259.25 24.81 1.47 1.7 5.8 0.57 402.14 115 18628572.6 2231516.3 6.7 45.74 6.76 18 18 0.14 0.07 0.01 262.3 14.18 1.26 6.2 0.68 0.54 374.33 116 18633582.3 2226127.3 6.5 33.91 3.43 28 19.2 5.5 0.07 0.01 222.65 46.08 0.3 0.01 0.05 0.34 360.2 117 18639406.8 2229826.9 6.7 60.27 3.72 20 18 2.3 0.09 0.01 286.7 17.62 17.72 0.51 0.69 0.06 0.43 427.69 118 18635366.4 2234249.1 6.8 61 4.36 20 12 0.14 0.14 0.09 274.5 3.89 10.63 1.89 3.95 0.08 0.54 392.66 85 119 18621839.4 2260408.3 6.7 220.09 6.72 128 48 18 0.08 42 189.1 753.31 0.21 0.77 0.19 0.37 1407.47 120 18612987.9 2257416.7 6.7 361.1 56.41 108 153.6 11.6 0.11 28.5 1281 4.55 620.38 1.77 0.38 10.7 0.36 2638.1 121 18620470.8 2257467.8 99.41 4.45 88 36 17 0.08 11 213.5 363.36 0.18 0.15 0.47 0.39 834.6 122 18618518 2254091.9 6.6 120.88 4.45 96 46.8 25 0.09 17.5 140.3 514.03 0.21 0.31 2.9 0.42 969.47 123 18641978.9 2266012 6.6 223.84 6.76 66 60 0.08 0.16 0.3 173.85 571.37 0.42 0.54 0.16 0.18 1104.48 124 18605528.7 2256508.7 6.5 480.93 21.09 176 196.8 39 0.13 25 9.15 1870 0.1 0.31 0.03 0.42 2819.54 125 18622353.7 2244478.1 213.37 15.09 44 33.6 4.7 0.36 0.09 295.85 357.25 0.39 3.02 0.39 0.46 969.11 126 18599000 2254200 631.85 21.33 286 229.2 26 0.11 3.25 106.75 1.28 2259.9 0.23 9.2 0.37 3576.1 127 18636131.4 2234195.1 7.2 45.74 3.99 24.8 16.32 0.04 0.28 0.08 262.3 9.64 10.64 0.99 0.01 0.04 0.47 374.86 128 18606416.2 2224358.1 6.7 383.36 23.22 200 163.2 3.9 0.09 0.01 164.7 4.67 1471.2 0.48 1.86 0.06 0.29 2416.75 129 18601357.5 2237508.2 6.9 197.26 8.15 188 93.6 4.4 0.61 0.01 286.7 822.25 0.75 0.31 2.85 0.35 1605.89 ... that the work which is being presented in this thesis entitled, ? ?Numerical simulation for the assessment of groundwater safe yield in Red River Delta, Viet Nam? ?? in partial fulfillment of the requirement... River to the north of Tan De Bridge, flowing through the city of Nam Dinh to The Day River in Nghia Minh commune before joining the ocean The Ninh Co River is a tributary of the Red River, located... improve groundwater management for the province by analyzing the simulation results In the northern areas of Nam Dinh Province, due to the the high concentration of contamination in the groundwater