GROUNDWATER MODELING SYSTEM
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The document discusses a groundwater modeling system developed by Thakur, Chaudhary, Khatso, and Singh, highlighting its graphical user environment and support for various numerical models, including MODFLOW. It presents a case study of the Bou-Areg aquifer in northeastern Morocco, where the model was used to analyze groundwater contamination and develop management strategies. The findings indicate that the aquifer is sensitive to recharge, and pollution migration is low, taking potentially 1000 years to reach the lagoon.
GROUNDWATER MODELING SYSTEM
- 1. Groundwater Modeling System Presented by Chandra Vanshi Thakur(17WM60R07) Shyam Mohan Chaudhary(17AG62R13) Visuto Khatso(17AG62R14) Rajnish Singh(17AG62R18)
- 2. UTILITY OF THE MODEL • Comprehensive graphical user environment for performing groundwater simulations. • provides tools for every phase of a simulation – site characterization, – model development, – calibration, – post-processing and – visualization.
- 3. GMS CAN BE DOWNLOADED FROM https://www.aquaveo.com/downloads co Contains all core components, all tools of site characterization, additional models and ARC-GIS extensions
- 4. MODEL FRAMEWORK • Several numerical models are currently supported in GMS. • MODFLOW – MODFLOW is a 3D, cell-centered, finite difference, saturated flow model developed by the USGS. – The governing equation (partial-differential flow equation) can be approximated by replacing the derivatives with finite differences.
- 5. continued… Governing Groundwater flow equation The saturated flow modeling is based transient on the three- dimensional Darcy equation where Kxx, Kyy, Kzz are the hydraulic conductivity along the x, y and z axes , h is the hydraulic head, Q represents the source/sink terms, and S is the storage coefficient
- 7. MODPATH
- 8. OTHER TRANSPORT MODELS • MT3DMS • RT3D • SEAM3D • MODAEM • FEMWATER • SEEP2D
- 9. INPUT DATA REQUIREMENTS • Base map. • Boundary conditions. • Rainfall and evaporation data for the entire study area. • Groundwater level to define the initial and boundary condition and for calibration and validation. • Aquifer properties. • Groundwater abstraction data.
- 10. INPUT DATA REQUIREMENTS • The input file formats – ASCII files (.TXT, .ASC, .DAT), – MS Access Database files (.MDB), – MS Excel files (.XLS), – ESRI Point files (.SHP), – USGS DEM files (.DEM), – ESRI grid files (.GRD) – http://india-wris.nrsc.gov.in/ – https://www.ncdc.noaa.gov/cdo-web/ – http://www.indiawaterportal.org/met_data/
- 11. OUTPUT DATA • Hydraulic Heads • Drawdown • Flow rates • Mass Balance • Iteration information. • The velocity vectors, path lines, water table contours, concentration contours can be seen in 2D or 3D according to the selection.
- 12. MODEL RUN (step by step)
- 13. SAMPLE PROBLEM
- 14. EXTRA AVAILABLE DATA • Vertical anisotropy (Kh/Kv) – Layer 1 = 10 – Layer 2 = 5 • Grid size : 22860 m x 22860 m. • Cell size : 1524 m x 1524 m. • Grid consists of 15 rows and 15 columns. • Top layer wells: 12 with discharge 12230 m3/day each • Middle layer wells: 2 with discharge 12230 m3/day each • Bottom layer well: 1 with discharge 0.15 m3/day
- 15. EXTRA AVAILABLE DATA • LAKE : Constant head boundary on the left. (first two layers) (30 cells) • Starting heads will be set equal to zero • Steady state solution will be computed. DRAIN
- 16. MODELING WITH GRID APPROACH • Units • Creating the Grid • Creating the MODFLOW simulation • Assigning IBOUND values directly to cells • LPF package • Recharge Package • Drain Package • Well Package • Checking and saving the simulation • Running MODFLOW • Viewing the solution • Zone Budget • Conclusion
- 17. MODEL INTERFACE
- 18. SETTING UP UNITS
- 19. SETTING UP UNITS
- 20. SETTING UP UNITS
- 27. THE IBOUND ARRAY
- 28. THE IBOUND ARRAY
- 29. THE IBOUND ARRAY
- 30. TOP AND BOTTOM ELEVATIONS
- 31. TOP AND BOTTOM ELEVATIONS
- 32. TOP AND BOTTOM ELEVATIONS
- 33. TOP AND BOTTOM ELEVATIONS
- 34. TOP AND BOTTOM ELEVATIONS
- 35. ASSIGNING IBOUND VALUES DIRECTLY TO CELLS-VIEWING THE LEFT COLUMN
- 37. CHANGING THE IBOUND VALUE
- 38. CHANGING THE IBOUND VALUE
- 39. CHANGING THE IBOUND VALUE
- 40. CHANGING THE IBOUND VALUE
- 41. THE LPF PACKAGE
- 42. ENTRIES FOR THE TOP LAYER
- 43. ENTRIES FOR THE TOP LAYER
- 44. MIDDLE AND BOTTOM LAYER
- 53. THE WELL PACKAGES-TOP LAYER PACKAGE
- 54. THE WELL PACKAGES-TOP LAYER PACKAGE
- 55. THE WELL PACKAGES-TOP LAYER PACKAGE
- 59. CHECKING AND SAVING THE SIMULATION
- 60. CHECKING AND SAVING THE SIMULATION
- 61. CHECKING AND SAVING THE SIMULATION
- 62. CHECKING AND SAVING THE SIMULATION
- 63. CHECKING AND SAVING THE SIMULATION
- 64. CHECKING AND SAVING THE SIMULATION
- 65. RUNNING MODFLOW
- 66. RUNNING MODFLOW
- 68. CHANGING LAYERS
- 69. CHANGING LAYERS
- 70. COLOR FILL CONTOURS AND COLOR LEGEND
- 71. COLOR FILL CONTOURS AND COLOR LEGEND
- 72. COLOR FILL CONTOURS AND COLOR LEGEND
- 73. Color Fill Contours and Color Legend
- 74. COLOR FILL CONTOURS AND COLOR LEGEND
- 75. COLOR FILL CONTOURS AND COLOR LEGEND
- 76. COLOR FILL CONTOURS AND COLOR LEGEND
- 77. COLOR FILL CONTOURS AND COLOR LEGEND
- 78. VIEWING THE FLOW BUDGET
- 79. VIEWING THE FLOW BUDGET
- 80. VIEWING THE FLOW BUDGET
- 81. VIEWING THE FLOW BUDGET
- 82. CASE STUDY Modelling groundwater flow and advective contaminant transport in the Bou-Areg unconfined aquifer (NE Morocco)
- 83. PROBLEM STATEMENT • Since the groundwater there has been severely contaminated by salinization, most water for agricultural purposes is drawn from the river. • Effective strategies for both management and protection of groundwater resources are required to avoid future irreversible environmental impacts, such as depletion and deterioration of groundwater quality.
- 84. OBJECTIVES • To employ MODFLOW within the framework of the GMS to study the groundwater processes of the hydrogeological system of Bou-Areg unconfined aquifer • To perform particle tracking in the aquifer using MODPATH inside GMS framework .
- 85. METHODOLOGY STUDY AREA • The plain of Bou-Areg is located on the Mediterranean coast of northeastern Morocco. • The coastal plain of Bou-Areg covers 160 km2. • The waters of the lagoon are very salty, with average salinity levels between 37 g/l and 42 g/l during the past thirty years. • The climate of the study area is semi-arid to humid. Average annual precipitation is around 346 mm.
- 87. Data preparation • Analysis of pumping tests. – The Neuman and Theis solutions are applied to obtain hydraulic conductivity (1.1 × 10−6 to 5 × 10−4 m/s) storage coefficient (1.30 × 10−4 and 3 × 10−2) Vertical anisotropy (3 to 15) The water balance technique is used to estimate the recharge (9.2 × 106 m3/year) R=P−Q −RET −ΔW Mod el s etu p • finite-difference model grid (500 m x 500 m) 28 rows and 53 columns. • layer one thickness between 5 and 11 m. • layers two and three, which are each 25 m thick.
- 88. BOUNDARY CONDITIONS Grid, model boundary conditions and recharge zones of Bou-Areg aquifer system
- 89. Outcomes
- 90. Estimated hydraulic conductivity (in 10−4 m/s) of layer 1 of Bou-Areg aquifer (obtained from PEST optimization method)
- 91. Estimated hydraulic conductivity (in 10−4 m/s) of layer 2 of Bou-Areg aquifer (obtained from PEST optimization method).
- 92. Scatter plot of observed weighted versus computed weighted values of head for steady state calibration flow model (1990).
- 93. WATER BALANCE The water budget of the entire aquifer obtained from the groundwater flow model
- 95. CONCLUSIONS • The results of the model calibration show reasonable agreement between observed and calculated water levels for the observation wells. • The horizontal hydraulic conductivity, obtained from the model calibration, ranges between 3 × 10−4 and 2 × 10−6 m/s. • The model aquifer is more sensitive to recharge than to hydraulic conductivities and storativity. • The MODPATH results show that migration of pollutants from the upstream of the aquifer towards the lagoon is very slow and could attain the Bou-Areg lagoon in 1000 years.
- 96. FUTURE SCOPE • Since MODFLOW is based on FORTRAN programming language which is generally sophisticated, so attempts should be made to code the MODFLOW in user friendly language • Since GMS involves the use of various models flow, transport and optimization, A DSS should be generated to assist and help decision makers in decision making process
- 97. THANK YOU…