L29– Water Quality Modeling
M odu le 7 – ( L2 7 – L3 0 ) : “ “ M a n a ge m e n t of W a t e r Qu a lit y”: f
li ”
W a t e r qu a lit y a n d pollu t ion , t ype s a n d Sou r ce s of pollu t ion ,
w a t e r qu a lit y m ode lin g, e n vir on m e n t a l gu ide lin e s for w a t e r w a t e r qu a lit y m ode lin g e n vir on m e n t a l gu ide lin e s for w a t e r
qu a lit y W a t e r Qu a lit y M ode lin g W a t e r Qu a lit y M ode lin g 2 9 2 9
W a t e r Qu a lit y M ode lin g Q y g
L29– L29
Topics Cove r e d
Wat er qualit y, prot ect ion, qualit y goals, W t W t Wat er qualit y, prot ect ion, qualit y goals, lit lit t t t i t i lit l lit l Hydrodynam ics, Transport processes, Hydrodynam ics, Transport processes,
Oxygen regim e, Mat hem at ical m odeling, Oxygen regim e, Mat hem at ical m odeling,
Governing equat ions, num erical m odeling, Governing equat ions, num erical m odeling, Groundw at er t ransport m odeling. Groundw at er t ransport m odeling.
Wat er qualit y m odeling, Hydrodynam ics, Wat er qualit y m odeling Hydrodynam ics Wat er qualit y m odeling Hydrodynam ics Wat er qualit y m odeling, Hydrodynam ics,
Keywords: Keywords: Keywords: Keywords: Mat hem at ical/ num erical m odeling, Groundw at er t ransport Mat hem at ical/ num erical m odeling, Groundw at er t ransport ..
I nt roduct ion -- Wat er Qualit y Modeling I nt roduct ion Wat er Qualit y Modeling
Wat er qualit y m odels sim ulat e t he fat e of pollut ant s & st at e of select ed wat er qualit y variables in wat er bodies bodies
I ncorporat es variet y of physical, chem ical, & biological processes which cont rol t he t ransport and t ransform at ion of t hese variables
Tem perat ure, solar radiat ion, wind speed, pH, and
light at t enuat ion coefficient s – im port ant param et ers light at t enuat ion coefficient s im port ant param et ers Wat ershed pollut ant loading
Each wat er qualit y m odel has it s own set of charact erist ics and requirem ent s- ( som e m odels can be applied t o several t ypes of wat er bodies and som e m odels only for part icular wat er bodies) y p
) Types of Wat er Qualit y Modeling Types of Wat er Qualit y Modeling
Wat er qualit y is m odeled by one or m ore of t he
follow ing form ulat ions: g Advect ive t ransport form ulat ions;
Dispersive t ransport form ulat ion;
Dispersive t ransport form ulat ion;
Heat budget form ulat ion; Di l d t t i R t i
Dissolved oxygen sat urat ion; Reaerat ion
Carbonaceous deoxygenat ion, Sedim ent , BOD,
pH, Alkalinit y, Nut rient s, Algae, Microorganism et c Wat er Qualit y – Wat er Qualit y – Hydrological Cycle Hydrological Cycle
Em issions: ( Ex = out of) from t he user’s point of view ( com m unit y, fact ory, et c. )
Avoidance and reduct ion of pollut ion int o t he environm ent - sanit ary engineering
I m m issions: I m m issions: ( I n ( I n = int o) - from t he wat er body’s point int o) from t he wat er body s point of view: consequences of pollut ion, inj ect ions, et c.
Environm ent al fluid m echanics: flow and t ransport in surface w at ers ( rivers and lakes) ; flow and t ransport f t ( i d l k ) fl d t t in soil and groundwat er; flow & t ransport in t he
Overland Precipitation at m osphere
Evaporation Hydrologic processes Land Hydrology Groundw ater
Wat er Qualit y Modeling Wat er Qualit y Modeling – – Wat er Cycle Wat er Cycle
I n du st r y La w s Pr oce ss e n gin e e r in g Tr a de La w s St or m w a t e r ove r flow D om e st ic La w s D r in k in g & in du st r ia l w a t e r W a st e w a t e r t r e a t m e n t
La w s Re ce ivin g w a t e r body in du st r ia l w a t e r t r e a t m e n t Re ce ivin g w a t e r body Gr ou n dw a t e r Wat er Qualit y Prot ect ion– Wat er Qualit y Prot ect ion – Goals Goals
Wat er qualit y prot ect ion - ensure t he qualit y of wat er which guarant ees t he preservat ion of environm ent al goods. goods.
En vir on m e n t a l Goods :
funct ions of t he river as wat er resource; com m unit y of aquat ic living; fishing; irrigat ion of farm land l f h f f l d
leisure and recreat ion; focus on cont am inat ion
subst ances from inland & suspended solids & sedim ent s; subst ances from inland & suspended solids & sedim ent s;
drinking wat er supply
Qu a lit y goa ls: given as a concent rat ion of a subst ance -
show condit ion of river w it h regard t o t he environm ent al h di i f i i h d h i l goods - funct ion as an inst rum ent for decisions, prot ect ion & im provem ent of wat er qualit y; derived from effect ive values & law
Wat er Qualit y Modeling Wat er Qualit y Modeling -- Considerat ions Considerat ions
Water Substances - W a t e r Su bst a n ce s D issolve d Em u lsifie d Pa r t icle s
Wat er Qualit y Modeling Wat er Qualit y Modeling -- Considerat ions Considerat ions
Governing laws -
Con se r va t ion La w s
M a ss M om e n t u m Su bst a n ce s in w a t e r En e rgy/ h e a t
Ele m e n t a r y CV - M icr o CV – M a cr o sca le Ele m e n t a r y CV M icr o
Wat er Qualit y Wat er Qualit y – – Mat hem at ical Modeling Mat hem at ical Modeling
The predict ion of wat er pollut ion using m at hem at ical sim ulat ion t echniques. sim ulat ion t echniques.
A t ypical wat er qualit y m odel consist s of a collect ion of A t ypical wat er qualit y m odel consist s of a collect ion of form ulat ions represent ing physical m echanism s t hat form ulat ions represent ing physical m echanism s t hat det erm ine posit ion and m om ent um of pollut ant s in a det erm ine posit ion and m om ent um of pollut ant s in a det erm ine posit ion and m om ent um of pollut ant s in a det erm ine posit ion and m om ent um of pollut ant s in a wat er body. wat er body.
Models are available for individual com ponent s of t he hydrological syst em such as surface runoff
Models addressing hydrologic t ransport and for ocean Models addressing hydrologic t ransport and for ocean and est uarine applicat ions. and est uarine applicat ions. and est uarine applicat ions and est uarine applicat ions
Wat er Qualit y Modeling Wat er Qualit y Modeling -- Hydrodynam ics Hydrodynam ics
Conservat ion of Mass: M a ss ba la n ce in a CV
I ncom pressible fluids
Wat er Qualit y Modeling Wat er Qualit y Modeling -- Hydrodynam ics Hydrodynam ics
Conservat ion of Mom ent um –
Navier- St okes equat ions
Wat er QM-- Hydrodynam ics & Transport Wat er QM Hydrodynam ics & Transport
Diffusive processes: Molecular diffusion; Turbulent diffusion & dispersion
Molecular diffusion is a t ransport process t hat Molecular diffusion is a t ransport process t hat
originat es from m olecular act ivit y ( Brownian m ovem ent ) . The driving force for m olecular diffusion is a concent rat ion gradient . is a concent rat ion gradient . The m olecular diffusion is described by t he m olecular diffusion coefficient Dm .
Wat er QM – Wat er QM – Hydrodynam ics & Transport Hydrodynam ics & Transport
Turbulent flow: Turbulent flow: N a t u r e of t u r bu le n ce : irregular N a t u r e of t u r bu le n ce : irregular ( charact erized by variat ions wit h respect t o t im e) ; int ensive m ixing; rot at ion; dissipat ive ( increased losses of energy) of ene g )
Tu r bu le n t flu ct u a t ion
W a t e r QM W a t e r QM -- H ydr odyn a m ics & Tr a n spor t H ydr odyn a m ics & Tr a n spor t
Turbulent flow : Cont inuit y & m om ent um ( x- dir.)
Wat er Qualit y Modeling Wat er Qualit y Modeling
Diff i Diffusion Dispersion in a River
Turbulence WQM WQM-- Transport in Rivers & Canals Transport in Rivers & Canals
One dim ensional t ransport : WQM WQM-- Transport in Rivers & Canals Transport in Rivers & Canals
On e dim e n sion a l t r a n spor t e qu a t ion
Tw o dim e n sion a l t r a n spor t e qu a t ion
Th r e e dim e n sion a l t r a n spor t e qu a t ion
Th r e e dim e n sion a l t r a n spor t e qu a t ion
WQM WQM-- Oxygen regim e of Rivers Oxygen regim e of Rivers
St reet er- Phelps Equat ion for oxygen regim e O2 cont ent in m g/ l Tim e in days
Gr ou n dw a t e r Tr a n spor t M ode lin g
V x y c D y x c
q
2D Transport equat ion x K v x x
y y y
W
'
R c nb W c c
V y c
D x t c R y x yy xx
h K v
' ) ( ) (
h K v y y
2D non- hom ogeneous confined aquifer Flow s i i w y x Q q y y x x t h S y h
T y x h T x
2D non- hom ogeneous s i i w y y x Q q y y x x t h S y h
) )( ( confined aquifer- Flow Equat ion
K y x h
K
x t y y x x
) )( (
2D non hom ogeneous unconfined aquifer- Flow Equat ion
Water Quality Water Quality – – Numerical Modeling Numerical Modeling Num erical procedures- approx. sol. t o m ost of field problem s.
Transform a com plex pract ical problem int o a sim ple discret e form of m at hem at ical descript ion form of m at hem at ical descript ion
Recreat e & solve t he problem on a com put er, & finally reveal Recreat e & solve t he problem on a com put er, & finally reveal phenom ena virt ually according t o requirem ent s of analyst s phenom ena virt ually according t o requirem ent s of analyst s.
Num erical or approxim at e solut ion for a com plex problem
efficient ly, as long as proper num erical m et hod is used. Num erical m et hods are used t o analyze t hese phenom ena like
Num erical m et hods are used t o analyze t hese phenom ena like
- – – Finit e Difference Met hod ( FDM) Finit e Difference Met hod ( FDM)
- – – Finit e Elem ent Met hod ( FEM) Finit e Elem ent Met hod ( FEM)
- – Finit e Volum e Met hod ( FVM)
- – Met hod of Charact erist ics ( MoC) B d El M h d ( BEM) B d El M h d ( BEM)
- – – Boundary Elem ent Met hod ( BEM) Boundary Elem ent Met hod ( BEM)
W ASP Wat er Qualit y Analysis Sim ulat ion Program , US EPA: I nt erpret & predict wat er qualit y responses t o nat ural
phenom ena and m anm ade pollut ion for various pollut ion phenom ena and m anm ade pollut ion for various pollut ion
m anagem ent decisions QUAL2K - river and st ream wat er qualit y m odel
sim ulat ion m odel for aquat ic syst em s; Aquat ox- predict s t he fat e of various pollut ant s, such as nut rient s & organic chem icals, & effect s on ecosyst em nut rient s & organic chem icals, & effect s on ecosyst em
Riverine Hydrodynam ic and Wat er
Qualit y Model, a syst em of program s t o perform 1D
dynam ic hydraulic & wat er qualit y sim ulat ions St orm Wat er Managem ent ModelSWMM – Groundwat er Qualit y Models MODFLOW ( 1988) - USGS flow m odel for 3- D aquifers aquifers
MODPATH - flow line m odel for depict ing st ream lines
MOC ( 1988) - USGS 2- D advect ion/ dispersion code
MT3D ( 1990, 1998) - 3- D t ransport code works wit h
MODFLOW RT3D ( 1998) 3 D t ransport chlorinat ed RT3D ( 1998) - 3- D t ransport chlorinat ed – MODFLOW BI OPLUME I I , I I I ( 1987, 1998) - aut hored at Rice Univ 2- D based on t he MOC procedures. FEMWATER GMS package GMS package
Groundwat er Transport Modeling – Case St udy
Dh Dhar et al., (1999), NGRI Report; t l (1999) NGRI R t M. Meenal & T. I. Eldho, (2012) M M l & T I Eldh (2012) Submitted to Journal of Hydrologic Engineering, ASCE HI NDACO- Belgaum , I ndia) 7000 8000 N
6000 Zone I 5000 L Factor Kekti Kekti 1 1 2 2 ) m y 4000
Yamunanag Y ( Zone II ar Markandey Gundv 3000 a River Nehrunag ad ad
Zone ar 2000
III 1,2 – Red L– Lagoon 1000 Mud
Case study.
Wat ershed area- 72 sq. km , basalt ic Wat ershed area 72 sq km basalt ic t errain on nort hern side of Belgaum .
Parameter Value
Wat ershed is drained by Markandeya Hydraulic y river in t he nort h river in t he nort h
Conductivity
Red m ud- hydrous silt m uddy, highly (m/ day) alkaline solid wast e produced by physical and chem ical t reat m ent s of p y
Zone I Zone I
0.5 bauxit e in alum ina product ion. Zone II
0.5
1
Red m ud is harm ful t o t he ecological Zone III
2 environm ent , safet y of it s st orage has becom e an environm ent al problem of b i l bl f
Longitudinal i di l
50 concern. dispersivity (m)
Nat ural recharge of 65 m m / yr is given
Transverse Transverse
5 as input t o t he flow m odel as input t o t he flow m odel. dispersivity (m)
5
The seepage from red m ud ponds is sim ulat ed as addit ional recharge ( 130
Specific Yield
0.2 m m / yr) from t he ponds. m m / yr) from t he ponds Mat egaonkar, Meenal, ( 2012) . Ph.D. Thesis, Dept . Civil Engineer ing, I I T Bom bay Case study.. 4 1
8000 7500 1 6 7 9 10 12 7000 7000 1 6 6 6 8 8 9 1 1 6 6 1 1 6500 2 4 5 7 6000 5 1 2 3 3 6 5 6 6 8 5500 5500 3 3 5 5 1 1 3 7 7 5 3 3 8 8 102 5000 1 1 2 4 3 5 7 12 4500 9 3 3 9 ) 1 7 3 2 6 100 (m
4000 4 4 Y Y 2 3 5 5 3500 1 2 3 3 4 4 9 7 113 3000 6 2 9 Support 2500 Nodes 3 4 5 9 D Domain i 2000 6 Pumping 8 7 6 6 Mat egaonkar Meenal, Eldho T.I . ( 2011) . wells
Sim ulat ion of groundwat er flow &
1500 wells Observation 7 7 cont am inant t ransport in unconfined 122 1000 9 9 aquifer using Meshfree Point Collocat ion aquifer using Meshfree Point Collocat ion
Met hod. I PWE - 2011, Jan. 3- 7, 2011-
500
8000 7000 7500 8000
0.0025 6500 7000 6000 m/d 5500 5000 5000 750 750 755 6000 ) 4500 745 5000 5000 740 ) ( 4000 m
4000 3000 3500 730 735 Y( 2500 2000 3000 1000 1500 2000 500 600 12001800 2400300036004200 480054006000 6600720078008400 9000 1000 X (m)
900 1800 2700 3600 4500 5400 6300 7200 8100 9000 900 1800 2700 3600 4500 5400 6300 7200 8100 9000 X (m) Steady state head distribution Velocity distribution
7000 8000 8000 7000 7500 6000 5500 6000 6500 6500 ) (m ) Y 4000 5000 4000 4500 5000 (m Y Y 3000 3500 2500 3000 2000 1000 1500 1000 2000 600 12001800240030003600420048005400600066007200780084009000 X (m) 500 600 12001800240030003600420048005400600066007200780084009000 X (m) Concentration distribution after 20 yrs.
Head distribution after 20 yrs.
Re fe r e n ce s Re fe r e n ce s
Guidelines for Wat er Qualit y Managem ent , Cent ral pollut ion cont rol board ( CPCB)
Websit e : ht t p: / / w w w .cpcb.nic.in p / / p
Hydrological Modeling of Sm all Wat ershed – C.T Han, H.P.
Johnson, D.L. Brakensiek ( Eds.) , ASAE Monograph, Michigan
Freeze, R.A. and Cherry J.A. ( 1979) . Groundwat er Freeze R A and Cherry J A ( 1979) Groundwat er Prent ice . Pr en t i ce Hall- I NC., Englewood Cliffs, NJ w w w .epa.gov
ht t p: / / wrm in.nic.in
St andard Met hods for t he Exam inat ion of Wat er and Wast ewat er; APHA, AWWA, and WEF, 21st Edit ion, 2005.
ht t p: / / cgw b.gov.in/
Tu t or ia ls - Qu e st ion !.?
Crit ically st udy various groundwat er wat er and surface wat er qualit y wat er and surface wat er qualit y
m odels available in lit erat ure ( det ails
( eg. ( can be obt ained from I nt ernet : can be obt ained from I nt ernet : w w w .epa.gov ; www.bentley.com )
St udy t he capabilit ies of each m odel St udy t he capabilit ies of each m odel and t he problem s where it can be and t he problem s where it can be p p applied applied
Prof. T I Eldho, Department of Civil Engineering, IIT Bombay
Se lf Eva lu a t ion - Qu e st ion s!. Q
I llust rat e t he different t ypes of wat er qualit y m odeling.
Describe WQ m odeling w it hin t he perspect ive of w at er D ib WQ d li it hi t h t i f t
cycle. Explain various conservat ion laws used in WQ Explain various conservat ion laws used in WQ m odeling?.
Describe wit h governing equat ions, t he groundwat er Describe wit h governing equat ions, t he groundwat er
t ransport m odeling. I llust rat e t he role of num erical m odeling in WQ g Q m odeling.
Describe various m odels used in groundwat er qualit y m odeling
Assign m e n t - Qu e st ion s?. g Q
I llust rat e w at ershed based WQ issues w it hin t he perspect ive of Hydrologic cycle. perspect ive of Hydrologic cycle.
What are t he t ypical WQ problem goals?.
Describe w it h governing equat ions, t he surface Describe w it h governing equat ions t he surface w at er t ransport m odeling.
I llust rat e t he oxygen regim e m odeling in Rivers. I llust rat e t he oxygen regim e m odeling in Rivers
Describe various m odels used in surface w at er qualit y m odeling qualit y m odeling
Un solve d Pr oble m !. Un solve d Pr oble m !
Wit h reference t o a t ypical point source pollut ion Wit h reference t o a t ypical point source pollut ion
from an indust ry t o groundw at er in your from an indust ry t o groundw at er in yourwat ershed area, crit ically st udy t he possible wat ershed area, crit ically st udy t he possible t t h d h d it i it i ll ll t d t d t h ibl t h ibl
w at er qualit y m odeling for TDS concent rat ion. w at er qualit y m odeling for TDS concent rat ion. I dent ify t he possible w at er qualit y m odel from I dent ify t he possible w at er qualit y m odel from I dent ify t he possible w at er qualit y m odel from I dent ify t he possible w at er qualit y m odel from t he open sources ( from I nt ernet sources: like t he open sources ( from I nt ernet sources: like MODFLOW/ MT3D) . MODFLOW/ MT3D) .
Collect t he necessary dat a for t he w at er qualit y Collect t he necessary dat a for t he w at er qualit y m odeling. m odeling.
Try t o develop t he m odel for your st udy area Try t o develop t he m odel for your st udy area Try t o develop t he m odel for your st udy area Try t o develop t he m odel for your st udy area and predict t he fut ure spreading, say for next and predict t he fut ure spreading, say for next 10 years. 10 years. y y
Dr. T. I. Eldho Dr. T. I. Eldho Professor, Professor, Department of Civil Engineering, Department of Civil Engineering, p p g g g g Indian Institute of Technology Bombay, Indian Institute of Technology Bombay, Mumbai, India, 400 076. Mumbai, India, 400 076. Email: Email: Email: Email: eldho@iitb.ac.in eldho@iitb.ac.in eldho@iitb.ac.in eldho@iitb.ac.in