modeling of flow and transport in groundwater systems
DESCRIPTION
RESOURCE ASSESSMENT. SUSTAINABLE MANAGEMENT. CONTAMINANT MIGRATION. Modeling of Flow and Transport in Groundwater Systems. INTEGRATED MODELING. M. Sekhar Department of Civil Engineering Indian Institute of Science. BIOREMEDIATION. - PowerPoint PPT PresentationTRANSCRIPT
Modeling of Flow and Transport in Groundwater Systems M. Sekhar Department of Civil
Engineering Indian Institute of Science
RESOURCE ASSESSMENT
CM
SWAT MODFLOW
CM
SWAT MODFLOW
BIO
REM
ED
IATIO
N
INTEGRATED MODELING
SUSTAINABLE MANAGEMENT
CONTAMINANT MIGRATION
Groundwater discharge variationsGroundwater discharge variations
~ 1000 km~ 1000 km22Lower Lower Kabini Kabini BasinBasin
Sustainable Groundwater Management Under Climatic & Anthropogenic Effects Sustainable Groundwater Management Under Climatic & Anthropogenic Effects
0
400
800
1200
isD c h a rg eP re c ip ita t io nD e p th
0
400
800
1200
isD c h a rg eP re c ip ita t io nD e p th
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800
1200
isD c h a rg eP re c ip ita t io nD e p th
76-80 81-90 91-00 01-04Period
0
40
80
120
160
200
Wa
ter
Bal
an
ce
, m
m/y
ear
RechargeDischargePumping
EO
F A
naly
sis
GWL
Water table fluctuation & Chloride mass balance methods
Cumulative Rainfall Departure & Groundwater Levels
CRD
60 cm
100 cm
200 cm
Observed Simulated
Soil Moisture Retrieval & Modeling Using Assimilation MethodsSoil Moisture Retrieval & Modeling Using Assimilation Methods
Data used: 29th April 2005 – 29th March 2007
Numerical models for simulating profile soil moisture in soils using improved inversion (e.g. GLUE) and assimilation models (e.g. ensemble Kalman filter) are needed to characterize the land-surface fluxes under various soil cover conditions. Soil moisture prediction in plots for various crop types is developed. Near-surface soil moisture retrieval using ENVISAT satellite at watershed scale is under cropped areas is in progress. Field scale experiments to use future micro-wave Indian satellite (RISAT) are being developed.
Example: Simulations in soil plots with grass cover for understanding the evaporation and recharge fluxes
Numerical modeling for stochastic analysis of flow and Numerical modeling for stochastic analysis of flow and reactive solute transport in heterogeneous porous mediareactive solute transport in heterogeneous porous media
Scale dependent dispersivityB
O
C
D
P
A
1xL 2x
L
3xL
2xl
1xl
q1x2x
3x
Continuous source 0c
33--D problemD problem
B
O
C
D
P
A
1xL 2x
L
3xL
2xl
1xl
q1x2x
3x
Continuous source 0c
33--D problemD problem
Plume
Plume
LandfillLandfill
Plume
Plume
LandfillLandfill
Stochastic FEM
Modeling of the effect of contaminant sources in groundwater is needed to predict the development of the plume characteristics.
The random field modeling is required for analyzing the effect of heterogeneity in parameters (e.g. hydraulic conductivity, dispersivity, sorption and decay coefficient)
3-D stochastic flow and transport models are developed for analyzing the prediction uncertainty of concentration plumes due to the combined effect of randomness of system parameters and the input source conditions.
Stochastic Modeling of Flow Conditional to Watershed Investigations Stochastic Modeling of Flow Conditional to Watershed Investigations
12
34
567
8910 1
112
x
1
x
2
Stream outlet
Blue colour = Top clay layer (Blue colour = Top clay layer (RegolithRegolith))Green to yellow colour = Weathered rock (Green to yellow colour = Weathered rock (Fissured zoneFissured zone))Red colour = Fresh or fractured rockRed colour = Fresh or fractured rock
0
jij
i x
HK
x
xx
j
iji x
H
n
Kq
xx
x
Top fissure surfaceTop fissure surface Bottom fissure surfaceBottom fissure surface
4 4.5 5 5.5 6 6.5 7 7.5 8
x 10-5
0
2
4
6
8
10
12
14x 10
4
q (m3/sec)
p(q)
Case 1Case 2Case 3Case 4
Unconditional
Conditional
p(q)
K lowK high
Random Random surfacessurfaces
Hydrogeochemical Modeling – Theoretical & Field ApplicationsHydrogeochemical Modeling – Theoretical & Field Applications
3D Reactive Transport Model with equilibrium geochemical reactions (HYDROS)
Example: Sulphide mineral oxidation and transport of oxidation products from pyrite ore mine tailing dump
Multi-component transport of solutes in soil and groundwater system require modeling the geochemical reactions arising from the water-rock/sediment interactions.
A multidimensional numerical model (HYDROS) based on the finite volume method for the multi-component equilibrium reactive solute transport is developed, which combines the transport model with equilibrium speciation module MINTEQA2 (US geological survey).
HYDROS is evaluated and compared with the MINTOX simulations used to model the metal mobility in aquifers impacted by acid mine tailings discharge.
HYDROS is then applied to the case study of the transfer of transition metals with organic colloids in the swamp groundwater of the experimental Nsimi watershed, representative of the humid tropical ecosystem of the South Cameroon Plateau.
Research Areas & Future InterestsResearch Areas & Future Interests Groundwater resources assessment under climatic variations and
anthropogenic effects using numerical models, statistical tools and
field studies.
Retrieval of near surface soil moisture through radar remote
sensing (SAR) and estimation of profile soil moisture using
modeling and assimilation at watershed scale.
Stochastic modeling of flow and reactive solute transport in
heterogeneous porous media. Theoretical investigations and field
scale experiments.
Integrated geochemical and hydrological studies in tropical regions
using experimental watersheds.
Publications pertaining to the slidesPublications pertaining to the slides
Chaudhuri, A. and Sekhar, M. (2007) Stochastic finite element method for analysis of transport of nonlinearly sorbing solutes in 3-D heterogeneous porous media. Water Resources Research, 43, W07442.
Soumya, B., Sekhar, M., Riotte, J. and Braun, J.J. Non-linear regression model for spatial variation in precipitation chemistry for South India. Atmospheric Environment (In Press).
Mangiarotti, S., Sekhar, M., Javeed, Y., and Mazzega, P. Spatio-temporal analysis of groundwater dynamics due to climatic variability and land use changes. Hydrological Processes (Accepted).
Descloitres, M., Ruiz, L., Sekhar, M., Legchenko, A., Braun, J.J., Mohan Kumar, M.S. and Subramanian, S. (2007) Characterization of seasonal local recharge using Electrical Resistivity, Tomography and Magnetic Resonance Sounding. Hydrological Processes, doi. 10.1002/hyp.6608.
Sekhar, M., Braun, J. J., Hayagreeva Rao, K. V., Ruiz, L., Viers, J., and Dupre, B. (2007) Hydrogeochemical modeling of organo-metallic colloids in the Nsimi experimental watershed, South Cameroon. Environmental Geology (In Press).
Sekhar, M., Rasmi, S.N., Javeed, Y., Gowrisankar, D., and Ruiz, L. (2006). Modeling the groundwater dynamics in a semi-arid hard rock aquifer influenced by boundary fluxes, spatial and temporal variability in pumping/recharge. Advances in Geoscience, Hydrological Sciences (ed) Park, N., V. 4, p. 173-181