This document presents a model integration framework for assessing surface and subsurface water interaction. The framework couples the Soil and Water Assessment Tool (SWAT) hydrologic model with the MODFLOW groundwater model (SWAT-MODFLOW) to simulate the interaction between surface water and groundwater. It describes the components of the framework, including the SWAT and MODFLOW models, interfaces for coupling the models, and tools for pre- and post-processing. The framework is demonstrated through an application to the Fort Cobb Reservoir Experimental Watershed in Oklahoma.

1. A MODEL INTEGRATION FRAMEWORK FOR ASSESING
SURFACE AND SUBSURFACE WATER INTERACTION
Jorge A. Guzman1, Daniel Moriasi1, Prasanna Gowda2, Jean Steiner1, Patrick Starks1,
Jeff Arnold3, Raghavan Srinivasan4
1USDA‐ARS GRL, El Reno, OK; 2USDA‐ARS CPRL, Bushlands, TX; 3USDA‐ARS GSWRL, Temple, TX; 4Texas A&M, AgriLife Research, College
Station, TX
SWCS International Annual Meeting
Lombard, IL. July 27‐30, 2014

2. A MODEL INTEGRATION FRAMEWORK FOR ASSESSING SURFACE AND SUBSURFACE WATER INTERACTION
Improve process model simulation at the WS
• New research knowledge becomes available
• Finer spatio-temporal resolutions data
• Feedback fluxes
• Long-term impacts assessments
• Future scenarios
• Agro-ecosystem interactions
• Decrease uncertainty in model outputs
Surface
SubSurface

3. Guzman et al. (2012a, 2012b, 2013)
Surface
USZ
SZ
BF
OF
PET
I
DP CR
Ain
Aout
RO
PF
WF IR
• Distributed ET fluxes
• Distributed percolation fluxes
• Distributed groundwater
feedback fluxes
• Surface-groundwater interaction
Atmospheric-surface-subsurface hydrologic linkage
• Hydrologic cycle is a complex system
• Essential to account for in water budgets
A MODEL INTEGRATION FRAMEWORK FOR ASSESSING SURFACE AND SUBSURFACE WATER INTERACTION

4. A MODEL INTEGRATION FRAMEWORK FOR ASSESSING SURFACE AND SUBSURFACE WATER INTERACTION
SPELLmap
SWATmf
SWAT‐MODFLOW
Spatio‐Temporal Analysis
Visualization SWAT‐MODFLOW project
builder
Surface‐Subsurface integrated model
EB_ET
Model Integration Framework
ArcSWAT
SWAT project
builder

5. B→13s→ 1m→ Areafrac
B→14s→ 1m → Areafrac
B→22s→ 1m → Areafrac
B→23s→ 1m → Areafrac
B→24s→ 1m → Areafrac
B→31s→ 5m → Areafrac
B→32s→ 5m → Areafrac
A→33s→ 5m → Areafrac
A→34s→ 5m → Areafrac
A→41s→ 5m → Areafrac
A→42s→ 5m → Areafrac
A→43s→ 5m → Areafrac
A→52s→ 5m → Areafrac
A B A
D
E
C
xll,yll
xll,yll
0s 1s 9s
10s
79
19s
70s 78
60s
0m 3m
4m
8m 11m
1m
10m
7m
1w
2w
3w
4w
(b)
SWAT‐MODFLOW
domains indexation
(Lookup table)
SWATmf‐app
(SPELLmap)
SWATmf‐model †
Raster
Time series
• NAM, BAS, DIS,
NWT, LIST, UPW,
LPF, OC, RCH,
WEL, DRN, CHD,
GHB, RES
• Log file
• Update file
handles
• Lookup tables
• Contextual data
• MODFLOW outputs
(LIST, RCH‐S, HDS,
WEL‐S)
• SWAT outputs
SPELLmap
ArcSWAT
SWAT
project
• HDS time series
• HDS daily maps
• EXT time series
• Metrics
MODFLOW project SWAT‐MODFLOW project
SWAT
MODFLOW
Interface
† SWATmf‐model
HRU
Feature class
(a)
arcSWAT HRU polygon domain
SWAT HRU grid domain
MODFLOW cells grid domain
MODFLOW wells domain
A MODEL INTEGRATION FRAMEWORK FOR ASSESSING SURFACE AND SUBSURFACE WATER INTERACTION
Remote sensing grid domain
EB‐ET

6. A MODEL INTEGRATION FRAMEWORK FOR ASSESSING SURFACE AND SUBSURFACE WATER INTERACTION
The Fort Cobb Reservoir Experimental Watershed (FCREW)
USDA‐ARS Grazinglands Research Laboratory, Oklahoma

7. UNCERTAINTY CONSIDERATIONS IN CALIBRATION AND VALIDATION OF HYDROLOGIC AND WATER QUALITY MODELS
SPATIAL DISCRETIZATION & LINKAGE
Land Use
Slope
Soil Class
HRUs ID Grid
Extraction
Wells
Wells to HRUs
SURFACE DOMAIN
(30 x 30 m)
River
Network
FCREW
Lookup
Table
(b)
(c)
MODEL
CONCEPTUALIZATION
LAND USE
LANSAT
(a)

8. INTEGRATION OF ENERGY BALANCE EVAPOTRANSPIRATION & SWATmf MODEL
LANSAT
HRU indexEB_ET
Daily
ET Accounting
for at least 50%
of the water
budget

9. 0
2
4
6
8
Jan‐11 Mar‐11 May‐11 Jun‐11 Aug‐11 Oct‐11 Dec‐11
EVT (mm d‐1)
EB_ET SWAT
0
2
4
6
8
Jan‐11 Mar‐11 May‐11 Jun‐11 Aug‐11 Oct‐11 Dec‐11
EVT (mm d‐1)
EB_ET SWAT
2011 2011
INTEGRATION OF ENERGY BALANCE EVAPOTRANSPIRATION & SWATmf MODEL
W‐WTH W‐WTH
Subbasin 1 Subbasin 49
HRU 5
HRU 804

10. ‐8
‐6
‐4
‐2
0
2
4
6
Jan‐11 Mar‐11 May‐11 Jun‐11 Aug‐11 Oct‐11 Dec‐11
ET Deviation (mm d‐1)
HRU‐5 HRU‐804
INTEGRATION OF ENERGY BALANCE EVAPOTRANSPIRATION & SWATmf MODEL
Rainfall 460.5
Avg. RO 75
HRU‐5
EB_ET : 805.2
Model : 430.6
‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐
‐374.6
HRU‐804
EB_ET : 1114.8
Model : 474.1
‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐
‐640.7
2011
Model – EB_ET

11. Interfacing
Routines
Lookup tables
Contextual data
BAS, DIS, NWT,
LIST, UPW, LPF,
OC, RCH, WEL,
DRN, CHD,
GHB, RES
• Setup NAM, OC
• Log file
• Update file
handles
Interfacing
Routines
HRUs percolation
HRUs irrigation
• Updated RCH
• Updated WEL
• Log file
SWAT‐code
daily loop
MODFLOW‐code
Stress period
simulation
BAS, DIS, NWT,
LIST, UPW, LPF,
OC, DRN, CHD,
GHB, RES
Day =first
yes
no
Day =last
MODFLOW‐code
launch
1
SWATmf‐model
*.cio
SWAT data
MODFLOW‐code
close
END
SWAT ‐code
simulation
SWAT‐code
close
1
no
yes
coupled
yes
coupled
yes
2
no
2
no
coupled
no
yes
A MODEL INTEGRATION FRAMEWORK FOR ASSESSING SURFACE AND SUBSURFACE WATER INTERACTION

12. JAN FEB MAR
APR MAY JUN
JUL AUG SEP
OCT NOV DEC
Jul‐18‐11 Jul‐19‐11 Jul‐20‐11
Jul‐22‐11 Jul‐23‐11
(a) (b)
(c)
A MODEL INTEGRATION FRAMEWORK FOR ASSESSING SURFACE AND SUBSURFACE WATER INTERACTION

13. A
A’ B
B’C
C’
CROSS SECTION
Distance
20,00015,00010,0005,0000
480
460
440
420
400
380
360
CROSS SECTION
Distance
25,00020,00015,00010,0005,0000
500
480
460
440
420
400
380
CROSS SECTION
Distance
30,00025,00020,00015,00010,0005,0000
520
500
480
460
440
420
400
380
A
A’ B
B’C
C’
Core2
Eakly
Alfalfa
A-A’
B-B’
C-C’
GWL
GWL
GWL
Marlow Formation
Marlow Formation
Marlow Formation
Rush Spring Aquifer
Rush Spring Aquifer
Rush Spring Aquifer
Core2 Alfalfa
Alfalfa
Eaklyn
Eaklyn
Core2
Jul 17‐11
(a) (b)
(c)
Top MODFLOW boundary
Terrain surface
Simulated
groundwater level
Observed
Simulated
Alfalfa
Core2
Eakly
A MODEL INTEGRATION FRAMEWORK FOR ASSESSING SURFACE AND SUBSURFACE WATER INTERACTION

14. INTEGRATION OF ENERGY BALANCE EVAPOTRANSPIRATION & SWATmf MODEL

15. A MODEL INTEGRATION FRAMEWORK FOR ASSESSING SURFACE AND SUBSURFACE WATER INTERACTION
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