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7/25/2019 Introduction to Groundwater Modeling.pptx
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Introduction to Groundwater Modelling
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Presentation Outline
Groundwater in Hydrologic Cycle
Why Groundwater Modelling isneeded?
Mathematical Models
Modelling Protocol
Model Design
Calibration and Validation
Groundwater Flow Models
Groundwater Modelling esources
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Groundwater in Hydrologic Cycle
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Types of Terrestrial Water
Ground water
Soil
Moisture
SurfaceWater
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Unsaturated Zone / Zone of Aeration / Vadose
(Soil Water
!ores "ull of Co#$ination of Air and Water
Zone of Saturation (Ground water
!ores "ull Co#pletely wit% Water
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Groundwater
portant source of clean water
More a$undant t%an SW
'ined to SW syste#s
Sustains flows
in strea#s
)aseflow
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pollution
Groundwater Concerns*
groundwater #ining
su$sidence
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Problems with groundwater
Groundwater o!erdra"t # mining # subsidence
Waterlogging
$eawater intrusion
Groundwater %ollution
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W%y Groundwater Modelling is needed*
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Groundwater
&n im%ortant com%onent o" water resource systems'
()tracted "rom a*ui"ers through %um%ing wells and
su%%lied "or domestic use+ industry and agriculture'
With increased withdrawal o" groundwater+ the *uality
o" groundwater has been continuously deteriorating'
Water can be in,ected into a*ui"ers "or storage and#or
*uality control %ur%oses'
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Manage#ent of a groundwater syste#+ #eans
#aing suc% decisionsas,
-he total !olume that may be withdrawn annually "rom the a*ui"er'
-he location o" %um%ing and arti"icial recharge wells+ and their
rates'
Decisions related to groundwater *uality'
Groundwater conta#ination $y,
Ha.ardous industrial wastes
/eachate "rom land"ills
&gricultural acti!ities such as the use o" "ertili.ers and %esticides
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M&0&G(M(0-means ma1ing decisionsto achie!e goalswithout
!iolating s%eci"ied constraints'
Good management re*uires in"ormation on the res%onse o" the
managed system to the %ro%osed acti!ities'
-his in"ormation enables the decision2ma1er+ to com%are alternati!e
actions and to ensure that constraints are not !iolated'
&ny %lanning o" mitigation or control measures+ once contamination
has been detected in the saturated or unsaturated .ones+ re*uires
the %rediction o" the %ath and the "ate o" the contaminants+ in
res%onse to the %lanned acti!ities'
&ny monitoring or obser!ation networ1 must be based on the
antici%ated beha!ior o" the system'
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& tool is needed that will %ro!ide this in"ormation'
-he tool "or understanding the system and its beha!ior
and "or %redicting this res%onse is the #odel'
3sually+ the model ta1es the "orm o" a set o"
mathematical e*uations+ in!ol!ing one or more %artial
di""erential e*uations' We re"er to such model as a
mathematical model'
-he %re"erred method o" solution o" the mathematicalmodel o" a gi!en %roblem is the analytical solution'
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-he ad!antage o" the analytical solution is that the
same solution can be a%%lied to !arious numerical!alues o" model coe""icients and %arameters'
3n"ortunately+ "or most %ractical %roblems+ because o"
the heterogeneity o" the considered domain+ the
irregular sha%e o" its boundaries+ and the non2analytic
"orm o" the !arious "unctions+ sol!ing the mathematical
models analytically is not %ossible'
Instead+ we trans"orm the mathematical model into anumerical one+ sol!ing it by means o" com%uter
%rograms'
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We should have a CALIBRATED MODELof the aquifer, especially,
e should !"o the aquifer#s "atural reple"ish$e"t %fro$precipitatio" a"d throu&h aquifer 'ou"daries()
*rior to deter$i"i"& the $a"a&e$e"t sche$e for a"yaquifer+
We should have a *OLIC that dictates $a"a&e$e"t o'-ectives
a"d co"strai"ts)
O'viously, e also "eed i"for$atio" a'out the ater de$a"d%qua"tity a"d quality, curre"t a"d future(,i"teractio" ith other
parts of the ater resources syste$, eco"o$ic i"for$atio", sources
of pollutio", effect of cha"&es o" the e"viro"$e"t...spri"&s, rivers,)))
The $odel ill provide the respo"se of the aquifer %ater levels,
co"ce"tratio"s, etc)( to the i$ple$e"tatio" of a"y $a"a&e$e"t
alter"ative)
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G-.U0 WAT1- M.01'&G
WH2 M.01'*
-o ma1e %redictions about a ground2water
system4s res%onse to a stress
-o understand the system
-o design "ield studies
3se as a thin1ing tool
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/se of 0rou"dater $odels
Can be used for three general purposes:
To predict or forecastexpected artificial
or natural changes in the system.Predictive is more applied to deterministic
models since it carries higher degree of
certainty, while forecasting is used withprobabilistic (stochastic) models.
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/se of 0rou"dater $odels
To describethe system in order to analyse
various assumptions
Togenerate a hypothetical system thatwill be used to study principles of
groundwater flow associated with various
general or specific problems.
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A'' G-.U03WAT1- H20-.'.G2 W.-4 &S M.01'&G
A Model is a representation of a syste#5
Modeling $egins w%en one for#ulates a concept of a
%ydrologic syste#+continues wit% application of+ for e6a#ple+
0arcy7s 'aw to t%e pro$le#+
and #ay
cul#inate in a co#ple6 nu#erical si#ulation5
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Ground Water "low Modelling
& Power"ul -ool"or "urthering our understanding
o" hydrogeological systems
Im%ortance o" understanding ground water "low models
Construct accurate re%resentations o" hydrogeological systems
3nderstand the interrelationshi%s between elements o"
systems
(""iciently de!elo% a sound mathematical re%resentation
Ma1e reasonable assum%tions and sim%li"ications
3nderstand the limitations o" the mathematical re%resentation
3nderstand the limitations o" the inter%retation o" the results
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&ntroduction to Ground Water "low Modelling
K
xqhxh 0)(
!redicting %eads 5and "lows6and
Appro6i#ating para#eters
$olutionsto the "low e*uations
Most ground water "low models are
solutions o" some "orm o" the
ground water "low e*uation
!otentio#etricSurface
)
))
ho
x0
h(x)
x
K q
7e'g'+ unidirectional+ steady2state "lowwithin a con"ined a*ui"er
-he %artial di""erential e*uation needs
to be sol!ed to calculate head as a
"unction o" %osition and time+
i'e'+ h8"5)+y+.+t6
h5x,y,z,t6?
K
xqhhdx
K
qdh
K
q
dx
dh xh
h
000
Darcy4s /aw Integrated
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-he only e""ecti!e way to test e""ects o"
groundwater management strategies
-a1es time+ money to ma1e model
Conce%tual model
$teady state model
-ransient model
-he model is only as good as its calibration
Groundwater Modeling
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Processes we might want to model
Groundwater "low
calculate both heads and flow
$olute trans%ort9 re*uires in"ormation
on "low 5!elocities6 calculate concentrations
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M.01'&G !-.C1SS
A'' &M!.-TAT M1CHA&SMS 8 !-.C1SS1S MUST
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T2!1S ." M.01'S
C.C1!TUA' M.01'9UA'&TAT&V1
01SC-&!T&. ." S2ST1M
:a cartoon of t%e syste# in your #ind:
MATH1MAT&CA' M.01'
MATH1MAT&CA' 01SC-&!T&. ."
S2ST1MS&M!'13 AA'2T&CA' (pro;ides a continuous solution o;er t%e #odel do#ain
C.M!'1
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Mat%e#atical Models
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Mathematical model:
simulates ground2water "low and#orsolute "ate and trans%ort indirectly by
means o" a set o" go!erning e*uationsthought to re%resent the %hysical%rocesses that occur in the system'
5&nderson and Woessner+ ;
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Com%onents o" a Mathematical Model
Go!erning (*uation
5Darcy4s law > water balance e*uation6
with head 5h6 as the de%endent !ariable
oundary Conditions
Initial conditions5"or transient
%roblems6
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) y @
y
)
.
;' Consider "lu) 5q6 through (V
=' O3- 9 I0 8 2 $torage
A' Combine with:q8 2B gradh
*
0eri;ation of t%e Go;erning 1=uation
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'aw of Mass )alance> 0arcy?s 'aw @
Go;erning 1=uation for Groundwater "low
333333333333333333333333333333333333333333333333333333333333333
divq8 2 $s 5ht6 (Law of Mass Balance)
q8 2 4grad h (Darcys Law)
div 54grad h6 8 $s 5ht6
5$s 8 $ # .6
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1(%(%(% =
+
+
h!
y
h!
yx
h!
xyx
General go!erning e*uation
"or steady2state+ heterogeneous+ anisotro%ic
conditions+ without a source#sin1 term
2(%(%(% "
h!
y
h!
yx
h!
xyx =
+
+
with a source#sin1 term
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2(%(%(% "
t
h#
h!
y
h!
yx
h!
x
syx
=
+
+
General go!erning e*uation "or transient+
heterogeneous+ and anisotro%ic conditions
$%eci"ic $torage
$s8 V # 5) y . h6
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Figures ta1en "rom Hornberger et al' 5;
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2(%(%(% "t
h#
h!
y
h!
yx
h!
xsyx
=
+
+
"t
h#
y
hT
yx
hT
xyx
=
+
(%(%
"t
h#
y
hh!
yx
hh!
xyx
=
+
(%(%
=D con"ined:
=D uncon"ined:
$torage coe""icient 5$6 is either storati!ity or s%eci"ic yield'
$ 8 $sb - 8 B b
General AD e*uation
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-y%es o" $olutions o" Mathematical Models
&nalytical $olutions: h8 "5)+y+.+t6
5e)am%le: -heis e*uation6
0umerical $olutions
Finite di""erence methods
Finite element methods
&nalytic (lement Methods 5&(M6
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-he "le)ibility o" analytical modeling is
limiteddue to sim%li"ying assum%tions:
Homogeneity+ Isotro%y+ sim%le geometry+
sim%le initial conditionsE
Geology is inherently com%le):
Heterogeneous+ anisotro%ic+ com%le)
geometry+ com%le) conditionsE
-his com%le)ity calls "or a more
%ower"ul solution to the "low e*uation 0umerical modeling
/imitations o" &nalytical Models
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Numerical Methods
h All numerical methods involverepresenting the flow domain by alimited number of discrete points called
nodes.h A set of equations are then derived to
relate the nodal values of thedependent variable such that they
satisfy the governing PDE, eitherapproimately or eactly.
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0umerical $olutions
Discrete solution o" head at selected nodal %oints'
In!ol!es numerical solution o" a set o" algebraic
e*uations'
Finite di""erence models5e'g'+ MODF/OW6
Finite element models5e'g'+ $3-&6
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"inite 0ifference Modelling
A2D Finite Di""erence Models
e*uires !ertical discreti.ation 5or layering6 o" model
B;B=BA
B
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"inite 1le#ents, basis "unctions+ !ariational %rinci%le+ Galer1in4s method+ weighted residuals
0odes %lus elements elements de"ined by nodes
0odes located on "lu) boundaries
Fle)ibility in grid design:
elements sha%ed to boundaries
elements "itted to ca%ture detail
(asier to accommodate anisotro%y that occurs at an
angle to the coordinate a)is
&ble to simulate %oint sources#sin1s at nodes
Pro%erties 5B+ $6 assigned to elements
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In!ol!es su%er%osition o" analytic solutions' Heads are
calculated in continuous s%ace using a com%uter to do
the mathematics in!ol!ed in su%er%osition'
Hybrid
Analytic 1le#ent Met%od (A1M
-he &( Method was introduced by Otto $trac1'
& general %ur%ose code+ GF/OW+ was de!elo%ed by
$trac14s student Hen1 Hait,ema+ who also wrote a
te)tboo1 on the &( Method: Analytic Element Modeling
of Groundwater Flow+ &cademic Press+ ;
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What is a model?
&ny 7de!iceJ that re%resents a%%ro)imation
to "ield system
Physical Models Mathematical Models
&nalytical
0umerical
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Modelling Protocol
(stablish the Pur%ose o" the Model De!elo% Conce%tual Model o" the $ystem $elect Go!erning (*uations and Com%uter Code Model Design
Calibration Calibration $ensiti!ity &nalysis Model Veri"ication Prediction
Predicti!e $ensiti!ity &nalysis Presentation o" Modeling Design and esults Post &udit Model edesign
Purpose What questions do you want the
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Purpose - What questions do you want the
model to answer?
Prediction $ystem Inter%retation Generic
Modeling
What do you want to learn "rom the model? Is a modeling e)ercise the best way to
answer the *uestion? Historical data?
Can an analytical model %ro!ide the answer?
Syste# &nterpretation, &n;erse Modeling, Sensiti;ity
Analysis
Generic, Used in a %ypot%etical sense+ not necessarily
for a real site
Syste# &nterpretation, &n;erse Modeling, Sensiti;ity
Analysis
Generic, Used in a %ypot%etical sense+ not necessarily
for a real site
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Model Overkill?
Is the !ast labor o" characteri.ing the system+combined with the !ast labor o" analy.ing it+disproportionateto the bene"its that "ollow?
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E!"#$
-here may be a chea%er+ more e""ecti!e
a%%roach
Warn o" limitations
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#onceptual ModelEverything should be made as simple as possible, but not simpler. Albert
Einstein
Pictorial re%resentation o" the groundwater
"low system
Will set the dimensions o" the model andthe design o" the grid
7ParsimonyJE'conce%tual model has been
sim%li"ied as much as %ossible yet retains
enough com%le)ity so that it ade*uatelyre%roduces system beha!ior'
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$elect #omputer #ode
$elect Com%uter Model Code Veri"ication
Com%arison to &nalytical $olutions Other
0umerical Models Model Design
Design o" Grid+ selecting time ste%s+
boundary and initial conditions+ %arameter
data set
Steady/Unsteady55+ B+ or 30D E
Heterogeneous/&sotropicE55&nstantaneous/Continuous
Steady/Unsteady55+ B+ or 30D E
Heterogeneous/&sotropicE55&nstantaneous/Continuous
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#ali%ration
$how that Model can re%roduce "ield2
measured heads and "low 5concentrations i"
contaminant trans%ort6
esults in %arameter data set that best
re%resents "ield2measured conditions'
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#ali%ration $ensitivity &nalysis
3ncertainty in In%ut Conditions
Determine (""ect o" 3ncertainty on
Calibrated Model
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Model 'eri(ication
3se Model to e%roduce a $econd $et o"
Field Data
Prediction Desired $et o" Conditions
$ensiti!ity &nalysis (""ect o" uncertainty in %arameter !alues and
"uture stresses on the %redicted solution
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Presentation o( Modelling
)esign and *esults (""ecti!e Communication o"
Modeling (""ort
Gra%hs+ -ables+ -e)t etc'
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Postaudit
0ew "ield data collected to
determine i" %rediction was correct
$ite2s%eci"ic data needed to
!alidate model "or s%eci"ic sitea%%lication
Model *edesign
Include new insights into system
beha!ior
UM1-&CA' M.01'&G
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UM1-&CA' M.01'&G
0&SC-1T&Z1
Write e=uations of GW "low $etween eac% node
0arcy7s 'aw
Conser;ation of Mass
0efine Material !roperties
)oundary Conditions
&nitial Conditions
Stresses
At eac% node eit%er H or 9 is nown+t%e ot%er is unnownn e=uations 8 n unnowns
sol;e si#ultaneously wit% #atri6 alge$ra
-esult H at eac% nown 9 node
9 at eac% nown H node
Cali$rate Steady State
Transient
Validate
Sensiti;ity
!redictions
Si#ilar !rocess for Transport Modeling only Concentration and "lu6 is unnown
UM1-&CA' M.01'&G
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UM1-&CA' M.01'&G
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Model 0esign
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M.01's 110
Geo#etry
Material !roperties (4+ S+ T+ Fe+ -+ etc5
)oundary Conditions (Head+ "lu6+ Concentration etc5
Stress 3 c%anging $oundary condition
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Model Desi&"
Conceptual Model
Selection of Computer Code
Model Geometry
Grid
Boundary array
Model Parameters
Boundary Conditions Initial Conditions
Stresses
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Co"cept Develop$e"t
$eveloping a conceptual model is the initial
and most importantpart of every modelling
effort. %t re&uires thorough understanding ofhydrogeology, hydrology and dynamics of
groundwater flow.
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Conceptual Model
A descriptive representationof a groundwater system that
incorporates an interpretation of thegeological & hydrological conditions.Generally includes information about
the water budget. May includeinformation on water chemistry.
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3electio" of Co$puter Code
'hich method will be used depends largely
on the type of problem and the nowledge of
the model design. low, solute, heat, density dependent etc.
*$, +$, $
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Model 0eo$etry
-odel geometry defines the sie and the
shape of the model. %t consists of model
boundaries, both external and internal, andmodel grid.
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Bou"daries
Physical boundariesare well defined
geologic and hydrologic features that
permanently influence the pattern ofgroundwater flow (faults, geologic units,
contact with surface water etc.)
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Bou"daries
Hydraulic boundariesare derived from the
groundwater flow net and therefore
artificial/ boundaries set by the modeldesigner. They can be no flow boundaries
represented by chosen stream lines, or
boundaries with nown hydraulic headrepresented by e&uipotential lines.
H20-AU'&C ).U0A-&1S
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& streamline5"lowline6 is also a
hydraulic boundary because by
de"inition+ "low is &/W&K$%arallel to a stream"low' It can
also be said that "low 0(V(
crosses a streamline there"ore it
is similar to an IMP(M(&/(
5no "low6 boundary
)UT
$tress can change the "low
%attern and shi"t the %osition o"streamlines there"ore care must
be ta1en when using a
streamline as the outer boundary
o" a model'
T2!1S ." M.01' ).U0A-2
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.3"'.W ).U0A-2
0either H(&D nor F/3 is
$%eci"ied' Can re%resent a
Physical boundary or a "low
/ine 5Groundwater Di!ide6
S!1C&"&10 H1A0 .-
C.STAT H1A0 ).U0A-2
h 8 constant
* is determined by the model'
&nd may be >!e or 9!e accordingto the hydraulic gradient de!elo%ed
T2!1S ." M.01' ).U0A-2 (cont?d
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(
S!1C&"&10 "'U< ).U0A-2
* 8 constant
h is determined by the model
5-he common method o" simulation
is to use one in,ection well "or each
boundary cell6
H1A0 01!10AT ).U0A-2
hb8 constant
* 8 c 5hb9 hm6
and c 8 " 5B+/6 and is called
CO0D3C-&0C(hmis determined by the model and
its interaction with hb
)oundary Types
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Specified Head/Concentration, a special case of constant %ead (A)C+ 1"G
Constant Head /Concentration, could replace (A)C+ 1"G
Specified "lu6, could $e rec%arge across (C0
o "low (Strea#line, a special case of specified flu6 (H&
Head 0ependent "lu6, could replace (A)C+ 1"G
"ree Surface, water3ta$le+ p%reatic surface (C0
Seepage "ace, pressure @ at#osp%eric at ground surface (01
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Bou"dary co"ditio"s i" Modflo
Constant head boundary
0ead dependent flux "iver Pacage
$rain Pacage 1eneral2head 3oundary Pacage
!nown lux "echarge
4vapotranspiration
'ells #tream
5o low boundaries
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I"itial Co"ditio"s
6alues of the hydraulic head for each activeand constant2head cell in the model. They
must be higher than the elevation of the cellbottom.
or transient simulation, heads to resembleclosely actual heads (realistic).
or steady state, only hydraulic heads inconstant head2cell must be realistic.
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Model *ara$eters
Time
#pace (layer top and bottom)
0ydrogeologic characteristics(hydraulic conductivity, transmissivity,
storage parameters and effective porosity)
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Ti$e
Time parameters are specified when
modelling transient (time dependent)
conditions. They include time unit, lengthand number of time steps.
7ength of stress periods is not relevant for
steady state simulations
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0rid
%n inite $ifference model, the grid is
formed by two sets of parallel lines that are
orthogonal. The blocs formed by theselines are called cells. %n the centre of each
cell is the node 8 the point at which the
model calculates hydraulic head. This type
of grid is called bloc2centered grid.
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0rid
1rid mesh can be uniform or custom, a
uniform grid is better choice when
4venly distributed a&uifer characteristics data The entire flow field is e&ually important
5umber of cells and sie is not an issue
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0rid
1rid mesh can be custom when
There is less or no data for certain areas
There is specific interest in one or more smaller
areas
1rid orientation is not an issue in isotropic
a&uifers. 'hen the a&uifer is anisotropic,
the model coordinate axes must be alignedwith the main axes of the hydraulic
conductivity.
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-egular ;s irregular grid spacing
Irregular s%acing may be used to obtain
detailed head distributions in selected areas
o" the grid'
Finite di""erence e*uations that use irregular
grid s%acing ha!e a higher associated error
than FD e*uations that use regular grid s%acing'
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Cur!ature o" the water table
Vertical change in head
Variability o" a*ui"er characteristics 5B+-+$6
Variability o" hydraulic %arameters 5+ @6
Considerations in selecting t%e sie of
t%e grid spacing
Desired detail around sources and sin1s 5e'g'+ ri!ers6
M.01' G-&0S
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M.01' G-&0S
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!rids
h "t is generally agreed that from a practicalpoint#of#view the differences between gridtypes are minor and unimportant.
h $%!% M&D'(&) employs a body#centred grid.
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Bou"dary array %cell type(
Three types of cells
%nactive cells through which no flow into or out
of the cells occurs during the entire time ofsimulation.
9ctive, or variable2head cells are free to vary in
time.
Constant2head cell, model boundaries with
nown constant head.
4 d li d i i d
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4ydraulic co"ductivity a"d
tra"s$issivity
0ydraulic conductivity is the most criticaland sensitive modelling parameter.
"ealistic values of storage coefficient andtransmissivity, preferably from pumping test,
should be used.
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Effective porosity
"e&uired to calculate velocity, used mainlyin solute transport models
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Cali$ration and Validation
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Calibration %arametersare uncertain %arameters
whose !alues are ad,usted during model calibration'
-y%ical calibration %arameters include hydraulic
conducti!ity and recharge rate'
Identi"y calibration %arameters and their reasonable
ranges'
In a real2world %roblem+ we need to establish model
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Calibration -argets
cali$ration;alue
associated error
=L'= m
+/L'L m
-arget with relati!ely
large associated error'
-arget with smallerassociated error'
s%eci"ic calibration criteria and de"ine targets including
associated error'
-argets used in Model Calibration
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Head measured in an obser!ation well is 1nownas a target'
-argets used in Model Calibration
-he simulated head at the node re%resenting the
obser!ation well is com%ared with the measured
head'
During model calibration+ %arameter !alues are
ad,usted until the simulated head matches the
obser!ed !alue'
Model calibration sol!es the in!erse %roblem'
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Cali'ratio" to 5lu6es
Whe" rechar&e rate %R( is a cali'ratio"
para$eter, cali'rati"& to flu6es ca" help i"esti$ati"& 7 a"d8or R)
In this example flux information
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K = ?
H; H=
* 8 BI
In this example, flux informationhelps calibrate .
In this example discharge
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R = ?
In this example, dischargeinformation helps calibrate !.
Calibration 2 emar1s
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Calibration emar1s
Calibrations are non2uni*ue'
& good calibration does not ensure that
the model will ma1e good %redictions'
0eed "or an uncertainty analysisto accom%any
calibration results and %redictions'
Kou can ne!er ha!e enough "ield
data' Modelers need to maintain a healthy s1e%ticism
about their results'
3ncertainty in the Calibration
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3ncertainty in the Calibration
In!ol!es uncertainty in:
Parameter !alues
Conce%tual model including boundary conditions+
.onation+ geometry etc'
-argets
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Ways to analy.e uncertainty
in the calibration
$ensiti!ity analysisis used as an uncertainty
analysis a"ter calibration'
3se an in!erse model 5automated calibration6
to *uanti"y uncertainties and o%timi.e the
calibration'
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3ncertainty in the Prediction
In!ol!es uncertainty in how %arameter !alues
5e'g'+ recharge6 will !ary in the "uture'
e"lects uncertainty in the calibration'
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$tochastic
simulation
Ways to *uanti"y uncertainty
in the %rediction
$ensiti!ity analysis
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Model Validation
How do we 7!alidateJ a model so that
we ha!e con"idence that it will ma1eaccurate %redictions?
Modeling C%ronology
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Modeling C%ronology
;
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7-he ob,ecti!e o" #odel ;alidationis to
determine how well the mathematical
re%resentation o" the %rocesses describes
the actual system beha!ior in terms o" thedegree o" correlation between model
calculations and actual measured dataJ'
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How to $uild confidence in a #odel
Calibration 5history matching6
7Veri"icationJ
re*uires an inde%endent set o" "ield data
Post2&udit: re*uires waiting "or %rediction to occur
Models as interacti!e management tools
411!&G A .!1 M&0
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411!&G A .!1 M&0
Consider all di#ensions of t%e pro$le# $efore co#ing
to a conclusion5
Considering all t%e stresses t%at #ig%t $e i#posed and
all t%e possi$le processes t%at #ig%t $e in;ol;ed in a
situation $efore reac%ing a conclusion5
411!&G A .!1 M&0 is spending IJ of your
T&M1 01T1-M&&G WHAT 2.U TH&4 &S HA!!1&G
and only IJ of your T&M1 01"10&G 2.U- .!&&.5
AV.&0 t%e co##on %u#an T-A! of -1V1-S&G
TH.S1 !1-C1TAG1S5
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Groundwater "low Models
Groundwater Flow Models
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Groundwater Flow Models
The most widely used numerical roundwater flow model isM!"F#!$ which is a three%dimensional model& oriinallyde'eloped y the *S* Geoloical Sur'ey*
It uses finite difference scheme for saturated +one*
The ad'antaes of M!"F#!$ include numerous facilitiesfor data preparation& easy e,chane of data in standardform& e,tended worldwide e,perience& continuousde'elopment& a'ailaility of source code& and relati'ely lowprice*
-owe'er& surface runoff and unsaturated flow are notincluded& hence in case of transient prolems& M!"F#!$can not e applied if the flu, at the roundwater taledepends on the calculated head and the function is not.nown in ad'ance*
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M.0"'.W
USGS code
"inite 0ifference Model
M.0"'.W KK
M.0"'.W L M.0"'.W B
M!"F#!$
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(Three%"imensional Finite%"ifference Ground%$ater Flow
Model)
$hen properly applied& M!"F#!$ is the reconi+ed
standard model*
Ground%water flow within the a/uifer is simulated in
M!"F#!$ usin a loc.%centered finite%difference
approach*
#ayers can e simulated as confined& unconfined& or a
comination of oth*
Flows from e,ternal stresses such as flow to wells& areal
rechare& e'apotranspiration& flow to drains& and flow
throuh ri'ereds can also e simulated*
MT0"
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(1 Modular 0" Solute Transport Model)
MT0" is a comprehensi'e three%dimensional numerical
model for simulatin solute transport in comple,
hydroeoloic settins*
MT0" is lin.ed with the SGS roundwater flow simulator&
M!"F#!$& and is desined specifically to handle
ad'ecti'ely%dominated transport prolems without the needto construct refined models specifically for solute transport*
F2F#!$
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(Finite 2lement Susurface Flow System)
F2F#!$ is a finite%element pac.ae for simulatin 0" and 3"
fluid density%coupled flow& contaminant mass (salinity) and
heat transport in the susurface*
-ST0"
(0%" -eat and Solute Transport Model)
The -eat and Solute Transport Model -ST0" simulates
round%water flow and associated heat and solute transport in
three dimensions*
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S21$1T
(Three%"imensional 4ariale%"ensity Ground%$ater Flow)
The S21$1T proram was de'eloped to simulate three%
dimensional& 'ariale% density& transient round%water flowin porous media*
The source code for S21$1T was de'eloped y cominin
M!"F#!$and MT0"into a sinle proram that sol'esthe coupled flow and solute%transport e/uations*
ST51
http://water.usgs.gov/software/modflow-88.htmlhttp://hydro.geo.ua.edu/mt3d/mt3dhome.htmhttp://hydro.geo.ua.edu/mt3d/mt3dhome.htmhttp://water.usgs.gov/software/modflow-88.html7/25/2019 Introduction to Groundwater Modeling.pptx
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(3%" Saturated6nsaturated Transport Model)
ST51 is a 3" roundwater saturated%unsaturated
transport model& a complete saltwater intrusion and enery
transport model*
ST51 employs a two%dimensional hyrid finite%element
and interated finite%difference method to appro,imate the
o'ernin e/uations that descrie the two interdependent
processes*
1 0%" 'ersion of ST51 has also een released*
S$IM
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(Soil water infiltration and mo'ement model)
S$IM'7 is a software pac.ae for simulatin water
infiltration and mo'ement in soils*
S$IM'3 is a mechanistically%ased model desined to
address soil water and solute alance issues*
The model deals with a one%dimensional 'ertical soil
profile which may e 'ertically inhomoeneous ut is
assumed to e hori+ontally uniform*
It can e used to simulate runoff& infiltration&redistriution& solute transport and redistriution of
solutes& plant upta.e and transpiration& e'aporation& deep
drainae and leachin*
4IS1# -2#P
(M d li 2 i t f 2 l ti d ! ti i i
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(Modelin 2n'ironment for 2'aluatin and !ptimi+in
#andfill "esins)
4isual -2#P is an ad'anced hydroloical modelin
en'ironment a'ailale for desinin landfills& predictin
leachate moundin and e'aluatin potential leachate
contamination*
4isual M!"F#!$
(Interated Modelin 2n'ironment for M!"F#!$ and
MT0")
4isual M!"F#!$ pro'ides professional 0" roundwater
flow and contaminant transport modelin usin
M!"F#!$ and MT0"*
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Groundwater Modelling -esources
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Groundwater Modeling esources
Bumar /in1s to Hydrology esourceshtt%:##www'angel"ire'com#nh#c%1umar#hydrology'html
3$G$ Water esources $o"tware Page
water'usgs'go!#so"tware
ichard ' Winston4s Home Pagewww'minds%ring'com#rbwinston#rbwinsto'htm
Geotech Geoen!iron $o"tware Directorywww'ggsd'com
International Ground Water Modeling Centerwww'mines'edu#igwmc
Ground Water Modelling Discussion Grou%
http://www.mines.edu/igwmchttp://www.mines.edu/igwmc7/25/2019 Introduction to Groundwater Modeling.pptx
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Ground Water Modelling Discussion Grou%
&n email discussion grou% related to ground water modelling and
analysis' -his grou% is a "orum "or the communication o" all as%ects
o" ground water modelling including technical discussions
announcement o" new %ublic domain and commercial so"twares calls
"or abstracts and %a%ers con"erence and wor1sho% announcementsand summaries o" research results+ recent %ublications+ and case
studies'
Grou% home %age : htt%:##grou%s'yahoo'com#grou%#gwmodel#
Post message : gwmodelQyahoogrou%s'com$ubscribe : gwmodel2subscribeQyahoogrou%s'com
3nsubscribe : gwmodel2unsubscribeQyahoogrou%s'com
/ist owner : gwmodel2ownerQyahoogrou%s'com
Visual MODF/OW 3sers Grou%
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Visual MODF/OW is a %ro!en standard "or %ro"essional AD
groundwater "low and contaminant trans%ort modeling using
MODF/OW2=LLL+ MODP&-H+ M-ADM$ &0D -AD' Visual
MODF/OW seamlessly combines the standard Visual MODF/OW
%ac1age with Win P($- and the Visual MODF/OW AD2()%lorer to gi!e
a com%lete and %ower"ul gra%hical modeling en!ironment'
-his grou% aims to %ro!ide a "orum "or e)change o" ideas and
e)%eriences regarding use and a%%lication o" Visual MODF/OW
so"tware'
Grou% home %age : htt%:##in'grou%s'yahoo'com#grou%#!isual2mod"low#
Post message : !isual2mod"lowQyahoogrou%s'co'in
$ubscribe : !isual2mod"low2subscribeQyahoogrou%s'co'in
3nsubscribe : !isual2mod"low2unsubscribeQyahoogrou%s'co'in
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"A##$ M%'((I)G
-H&0B$
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