Groundwater models are simplified representation of large and real hydrogeologic systems like river basins or watersheds. GWM is attempted to analyse the mechanisms which control the occurrence and movement of groundwater and to evaluate the policies, actions and designs which may affect the systems. These models are less complex prototypes of complex hydrogeologic systems developed using spatially varying aquifer parameters, hydrologic properties, geologic boundary conditions and positions of withdrawal wells or recharging structures. These are designed to compute how pumping or recharge might affect the local or regional groundwater levels.

1. GROUNDWATERGROUNDWATER
MODELLING AND GISMODELLING AND GIS
A. BalasubramanianA. Balasubramanian
Centre for Advanced Studies in Earth ScienceCentre for Advanced Studies in Earth Science
University of Mysore, Mysore-570 006University of Mysore, Mysore-570 006

2. Indian Scenario:Indian Scenario:
 Geographical area= 329 MhaGeographical area= 329 Mha
 Rainfall= 100mm to 11000 mmRainfall= 100mm to 11000 mm
 Annual precipitation= 4000 Cu.KmAnnual precipitation= 4000 Cu.Km
 Monsoon Precipitation= 3000 Cu.KmMonsoon Precipitation= 3000 Cu.Km
 Natural runoff( SW+GW)= 1953 Cu.KmNatural runoff( SW+GW)= 1953 Cu.Km
 SW resource-utilizable= 690 Cu.kmSW resource-utilizable= 690 Cu.km
 GW resource-replenishable= 432 Cu.KmGW resource-replenishable= 432 Cu.Km
 Total utilizable water= 1122 Cu.KmTotal utilizable water= 1122 Cu.Km
 Net GWR= 325 Cu.KmNet GWR= 325 Cu.Km
 Groundwater potential for domestic use=71 Cu.KmGroundwater potential for domestic use=71 Cu.Km

3. Major issues for Groundwater…..Major issues for Groundwater…..
 The quantum depends on the
hydrogeology
 The balance depends on inputs and
outputs
 depletes due to natural or man-
made means

4. Development ofDevelopment of
Groundwater resourcesGroundwater resources
calls for an integrated hydrogeological study
by amalgamating the results of
geomorphological,
hydometeorological, hydrogeological,
hydrochemical, geophysical and remote
sensing studies.

5. Approaches:Approaches:
 Basin-wise EvaluationBasin-wise Evaluation
 Watershed-wise evaluationWatershed-wise evaluation
 Old methods- manual assessmentOld methods- manual assessment
 New methods – digital assessmentNew methods – digital assessment
 Numerical Approaches- betterNumerical Approaches- better
evaluationevaluation

6. HydrogeologicalHydrogeological
Parameters:Parameters:
vary with reference to space andvary with reference to space and
time.time.
In some localities, it is difficult toIn some localities, it is difficult to
evaluate these parameters, due toevaluate these parameters, due to
non-availability of observationnon-availability of observation
wells and instruments andwells and instruments and
problems of accessibilityproblems of accessibility

7. Spatial Interpolation and parametricSpatial Interpolation and parametric
integration are the two prime tasksintegration are the two prime tasks
employed in groundwateremployed in groundwater
development.development.
With the advent of latest, userWith the advent of latest, user
friendly application software, thisfriendly application software, this
integration has become more easierintegration has become more easier
and simpler.and simpler.

8. The development of spatial
information could help the
user to store, process and
display the promising
potential zones for
groundwater development.

9. Mathematical models help inMathematical models help in
order toorder to
 evaluate the existing system ,evaluate the existing system ,
 generate new ideas,generate new ideas,
 test new applications / approachestest new applications / approaches
 identify the problem areas andidentify the problem areas and
 to reduce the cost of adhocto reduce the cost of adhoc
experimentation.experimentation.

10.  A digital model is a computer programA digital model is a computer program
that numerically solves the ratethat numerically solves the rate
equations by stepping through a seriesequations by stepping through a series
of time-steps during which the stateof time-steps during which the state
variables are updated.variables are updated.
 Several numerical models have beenSeveral numerical models have been
developed throughout the world fordeveloped throughout the world for
analyzing the dynamics of the wateranalyzing the dynamics of the water
resources environment.resources environment.

11. FAMILIES OF MATHEMATICALFAMILIES OF MATHEMATICAL
MODELSMODELS
 Hydraulic and hydrologic modelsHydraulic and hydrologic models
 Water quality modelsWater quality models
 Models of heat/solute transport in riversModels of heat/solute transport in rivers
 Groundwater flow modelsGroundwater flow models
 Groundwater contaminant transportGroundwater contaminant transport
modelsmodels
 Sea-water encroachment models andSea-water encroachment models and
 Geo-chemical models.Geo-chemical models.

12. TYPES OF MODELS
•PREDICTION
•IDENTIFICATION
•MANAGEMENT

13. FLOW MODELS
PREDICTION
SINGLE PURPOSE MULTI PURPOSE
DEFORMATION
MODELS
MASS
TRANSPORT
MODELS
HEAT
TRANSPORT
MODELS

14.  Identification models help in
estimating the unknown system
parameters, using the known
parameters
 Management models help in
evolving management plans based
on simulation runs with a precise
model.

15.  The basic theory used to describe this flowThe basic theory used to describe this flow
involves i) the equation of continuity andinvolves i) the equation of continuity and
 ii) the equation of motion.ii) the equation of motion.
 These equations permit the evaluation ofThese equations permit the evaluation of
spatial and temporal distribution of waterspatial and temporal distribution of water
flow rate, velocity and depth by adoptingflow rate, velocity and depth by adopting
the concept of mass-balance.the concept of mass-balance.
 The application of these equations withThe application of these equations with
appropriate data could yield the changesappropriate data could yield the changes
and dynamic characteristics of flow inand dynamic characteristics of flow in
channels.channels.

16. HYDROLOGIC MODELSHYDROLOGIC MODELS
 The hydrological processes of a river basin ,The hydrological processes of a river basin ,
movement of water or chemical in the soilmovement of water or chemical in the soil
horizon and along the river channels arehorizon and along the river channels are
controlled by many interdependent physicalcontrolled by many interdependent physical
phenomena in the earth’s spheres.phenomena in the earth’s spheres.
 River models, Ecosystem models- estuarineRiver models, Ecosystem models- estuarine
models, snow melt models &Reservoir models.models, snow melt models &Reservoir models.

17.  There are two categories of hydrologicalThere are two categories of hydrological
models as one dealing with themodels as one dealing with the quantity ofquantity of
surface flows and the other one deals withsurface flows and the other one deals with
the movement of chemicals and sedimentsthe movement of chemicals and sediments
along with the flow of water.along with the flow of water.
 The models of the first category consider theThe models of the first category consider the
long term mean values of precipitation,long term mean values of precipitation,
temperature, evaporation and runoff.temperature, evaporation and runoff.
 They are mostly similar to time series models,They are mostly similar to time series models,
capable of forecasting the runoff from rainfall.capable of forecasting the runoff from rainfall.

18. GROUNDWATER FLOWGROUNDWATER FLOW
MODELSMODELS
 Groundwater models are simplifiedGroundwater models are simplified
representation of large and real hydrogeologicrepresentation of large and real hydrogeologic
systems like river basins or watersheds.systems like river basins or watersheds.
 GWM is attempted to analyse the mechanismsGWM is attempted to analyse the mechanisms
which control the occurrence and movement ofwhich control the occurrence and movement of
groundwater and to evaluate the policies, actionsgroundwater and to evaluate the policies, actions
and designs which may affect the systems.and designs which may affect the systems.

19.  These models are less complex prototypes ofThese models are less complex prototypes of
complex hydrogeologic systems developedcomplex hydrogeologic systems developed
using spatially varying aquifer parameters,using spatially varying aquifer parameters,
hydrologic properties, geologic boundaryhydrologic properties, geologic boundary
conditions and positions of withdrawal wellsconditions and positions of withdrawal wells
or recharging structures.or recharging structures.
 These are designed to compute how pumpingThese are designed to compute how pumping
or recharge might affect the local or regionalor recharge might affect the local or regional
groundwater levelsgroundwater levels

20.  These models solve the basic partialThese models solve the basic partial
differential equations that govern the flow ofdifferential equations that govern the flow of
groundwater and solute transport through thegroundwater and solute transport through the
saturated and unsaturated porous medium.saturated and unsaturated porous medium.
 Models solve the equations analytically forModels solve the equations analytically for
simple geometric problems and appliessimple geometric problems and applies
numerical simulation to solve the equations ofnumerical simulation to solve the equations of
more complex hydrogeological problemsmore complex hydrogeological problems
involving aquifer heterogeneities, anisotropicinvolving aquifer heterogeneities, anisotropic
aquifer properties and complicated boundaryaquifer properties and complicated boundary
conditionsconditions

21. Categories:Categories:
 Flow and solute transport problems vary in 2 orFlow and solute transport problems vary in 2 or
3 dimensions.3 dimensions.
 The solution strategies may adopt techniquesThe solution strategies may adopt techniques
like finite difference, finite element andlike finite difference, finite element and
integrated finite difference approaches.integrated finite difference approaches.

22. FLOW MODELS
MULTI PHASE –
(IMMISIBLE))
SINGLE PHASE
(MISSIBLE)
LUMPED DISTRIBUTED
COMBINED
SUBSURFACE
—SURFACE
FLOW
UNSATURATED
FLOW
COMBINED
UNSATURATED
-SATURATED
FLOW
SATURATED-
FLOW
1-DIM
VERTICAL
2-DIM HORIZ
/ VERTICAL
FULLY
3-DIM

23. SATURATED FLOW
HYDRAULIC (DUPUIT’S
APPROXIMATION)
HYDRODYNAMIC
SINGLE
AQUIFER
SINGLE
AQUIFER
2 DIM
VERTICA
L
FULLY
3 DIM
AX1
SYMMETRI
C

24. Groundwater modelling requiresGroundwater modelling requires
 the following domain specificthe following domain specific
information:information:
 physical units,physical units,
 hydrologic conditions,hydrologic conditions,
 aquifer parameters ,aquifer parameters ,
 time varying inputs andtime varying inputs and
 boundary conditions.boundary conditions.

25. Fundamental equations:Fundamental equations:
 Two-dimensional case:
 d (Tx - dh) + d (Ty dh) = S dh + w(x,y,t)
 dx dx dy dy dy

 Three-dimensional case:
 d (Tx - dh) + d (Ty dh) + d (Tz dh) = S dh + w(x,y,z, t)
 dx dx dy dy dz dz dy

26. APPROXIMATION:APPROXIMATION:
 Finite Difference methodFinite Difference method
 Finite element methodFinite element method
 Integrated finite difference methodIntegrated finite difference method
 Boundary integral methodBoundary integral method
 Random walk methodRandom walk method
 Method of characteristics using FD/FEMethod of characteristics using FD/FE

35. Solution strategies:Solution strategies:
 ImplicitImplicit
 ExplicitExplicit
 Alternating direction explicitAlternating direction explicit
 Alternating direction implicitAlternating direction implicit
 Iterative alternating direction implicitIterative alternating direction implicit
 SORSOR

36. Aquifer types and issues:Aquifer types and issues:
 Homogeneous, Heterogeneous, Single layer,
multi-layered, confined , unconfined, leaky,
Lateral and vertical boundaries
 Recharge / barrier / closed / fixed
 Flow- steady state, transient, radial, linear,
bilinear
 Pumping schedules, no, loc, rates ?
 Fully/partially penetrating, small/large dia
 single /double porosity( Barrenblatt’s),
fractured/ sheared, Arbitrary fracture networks,
subsurface barriers/ dykes

37. Aquifer types and issues:Aquifer types and issues:
 Single layer, multi-layered, confined , unconfined,
leaky, Lateral and vertical boundaries
 Recharge / barrier / closed / fixed
 Flow- steady state, transient, radial, linear,
bilinear
 Pumping schedules, no, loc, rates ?
 Fully/partially penetrating, small/large dia
 single /double porosity( Barrenblatt’s), fractured/
sheared, Arbitrary fracture networks, subsurface
barriers/ dykes

38. CONTAMINANT TRANSPORTCONTAMINANT TRANSPORT
MODELSMODELS
 analyse the movement , mixing and chemicalanalyse the movement , mixing and chemical
reactions of various anthropogenic pollutantsreactions of various anthropogenic pollutants
entering into the groundwater system.entering into the groundwater system.

39. The three major processes are:The three major processes are:
Movement due to groundwaterMovement due to groundwater
flow(advection or convection),flow(advection or convection),
Mixing of groundwater and anMixing of groundwater and an
effluent(hydrodynamic dispersion)effluent(hydrodynamic dispersion)
Chemical reaction as ; (a) conservativeChemical reaction as ; (a) conservative
transport(models which do nottransport(models which do not
consider the chemical reactions (b)consider the chemical reactions (b)
non-conservative transport (modelsnon-conservative transport (models
which consider the chemicalwhich consider the chemical
reactions).reactions).

40. MASS TRANSPORT
MODELS
LUMPED PARAMETER DISTRIBUTED
PARAMETER
UNCOUPLED COUPLED
CONSERVATIVE
TRANSPORT
NON-
CONSERVATIVE
TRANSPORT
RANDOM WALK
MODELS

41. NON-CONSERVATIVE
TRANSPORT
ABIOTIC
PROCESSES
BIOTIC
PROCESSES

42. HEAT TRANSPORT MODELS
UNCOUPLED COUPLED
SINGLE PHASE MULTI PHASE
AQUIFER THERMAL ENERGY STORAGE MODELS
RADIACTIVE WASTE ENERGY DISSIPATION

43. SEA-WATER ENCROACHMENT MODELSSEA-WATER ENCROACHMENT MODELS
 In coastal areas, freshwater will overlie theIn coastal areas, freshwater will overlie the
saltwater because of the difference in density.saltwater because of the difference in density.
 A boundary surface between these two fluids isA boundary surface between these two fluids is
known as saltwater-freshwater interface. Bothknown as saltwater-freshwater interface. Both
these fluids will be normally in a state ofthese fluids will be normally in a state of
equilibrium.equilibrium.

44. Geochemical Models:Geochemical Models:
 interpret and predict the chemicalinterpret and predict the chemical
reactions of minerals, gases andreactions of minerals, gases and
organic matter with aqueousorganic matter with aqueous
solutions in real or hypotheticalsolutions in real or hypothetical
water-rock systems .water-rock systems .

45. Geochemical models aid toGeochemical models aid to
 identify geochemical processes that regulateidentify geochemical processes that regulate
the concentration of dissolved constituentsthe concentration of dissolved constituents
andand
 quantify the effects of temperature, speciation,quantify the effects of temperature, speciation,
sorption and solubility on the concentrationssorption and solubility on the concentrations
of dissolved constituents.of dissolved constituents.
 Ion activity of water , solubility of mineralIon activity of water , solubility of mineral
species and saturation indicesspecies and saturation indices

46.  a thorough understanding of the system,a thorough understanding of the system,
determination of the system parameters,determination of the system parameters,
equations,equations,
 solution strategies,solution strategies,
 computer coding,computer coding,
 database creation,database creation,
 calibration, sensitivity analysis, simulation andcalibration, sensitivity analysis, simulation and
applications.applications.
Any Modelling application
requires

47. Database Requirement:Database Requirement:
 GEOMORPHOLOGY-Topography -
(Watershed / Basin / District/ block ) - Basin
Boundary
 Drainage - River Course, Canals
(Lined/Unlined) – Channel Morphology
 Surface Water Bodies - Reservoirs -
Rainfed Tanks/ Ponds/Cess Pools / Lakes /
Estuaries /Impoundments
 Landuse/Land Cover / Soil / Vegetation /
Developmental Features

48. HYDROMETEOROLOGYHYDROMETEOROLOGY
 Rainfall - Pattern - Point
measurements - Long term Records -
(Polygon / Isohyets) -Specified intervels
 Evapotranspiration - Point
measurements - Areal distribution -
 Surface Runoff - Volumes - Specified
intervals –
 Soil thickness - Types - Moisture - Point
measurements -
 Infiltration rate of Soils - Point
measurements

49. HYDROGEOLOGYHYDROGEOLOGY
 Geology and structures - boundaries - variations - Aquifer
types - boundaries/geometry – weathered / fractured /
lateritic / volcanic / alluvial /coastal
 Aquifer thickness - areal distribution - depth to the
basement (bedrock)
 Distribution of deep/shallow fractures
 Water table elevation - long term records - closed network
 Aquifer parameters - point measurements - areal
distribution - (transmissivity (sp.yield)
 Confining/leaky layers - physical frame work and
characteristics
 Source of seepage/recharge - flow rates (irrigated open areas
- Location of recharge basins/wells, Sinks - location of wells -
pumping rates/schedules - spatial and time variant data

50.  OTHERS:OTHERS:
 Consumption Pattern - ChangesConsumption Pattern - Changes
In Space/TimeIn Space/Time
 Environmental Factors - QualityEnvironmental Factors - Quality

51. GISGIS
ProceduresProcedures
DataData
HardwareHardware
SoftwareSoftwarePeoplePeople

53. GIS - Links Data SetsGIS - Links Data Sets
 GIS software links theGIS software links the
location data and thelocation data and the
attribute data:attribute data:

54. GIS - AnalysisGIS - Analysis
GIS software can answer questions
about our world:
What provinces border
Saskatchewan?
Spatial Questions:
What provinces have more
than 1.5 million people?
Attribute Questions:

55. Base Map Data
GIS - LayersGIS - Layers
 GIS contains many layers of information:GIS contains many layers of information:
Elevation
Surface Geology
These are just a few of
the kinds of layers a
GIS can contain:

56. GIS - AnalysisGIS - Analysis
 GIS can analyze dataGIS can analyze data
in many ways:in many ways:

57. 3D Visualization3D Visualization

58. 3D Visualization3D Visualization

59. 3D Visualization3D Visualization

60. 3D BROWSER3D BROWSER

61. What do we have today?What do we have today?
 Many Modelling softwareMany Modelling software
 computers and staffcomputers and staff
 much needed databasesmuch needed databases
 GIS and other tools for spatial analysisGIS and other tools for spatial analysis
 experts to analyse/ interpretexperts to analyse/ interpret
 financial aid for applicationsfinancial aid for applications

62.  Competing water needs require a thoroughCompeting water needs require a thorough
analysis of the available water in a systemanalysis of the available water in a system
 Models are good tools for optimal planningModels are good tools for optimal planning
and management of available water resourcesand management of available water resources
 People need good training and hands-onPeople need good training and hands-on
experience in these two areasexperience in these two areas

63. Thank youThank you