SWAT Modeling of Water Quantity and Quality in the Tennessee River
Basin: Spatiotemporal Calibration and Validation
Supplement
Gangsheng Wang1,2,*, Henriette I. Jager1,2, Latha M. Baskaran1, Tyler F. Baker3, Craig C.
Brandt4
1
Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN
37831 USA
2
Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN
37831 USA
3
Tennessee Valley Authority, Knoxville, TN 37902 USA
4
Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
*Corresponding Author: Gangsheng Wang
Bldg 4500N, Room F129S, MS-6301
Oak Ridge National Laboratory
Oak Ridge, TN 37831-6301
wangg@ornl.gov
1
Table S1. Types of SWAT Calibration
Type ID
0
2
3
10
11
20
21
22
23
24
30
31
32
33
34
Response variables
Daily streamflow
Daily reservoir storage
Daily soil water content
Monthly streamflow
Monthly runoff: subbasin or HUC8
Monthly Flux: nutrient
• NO3+NO2
• NO3
• TN
• TP
• Sediment
Monthly Flux: Sediment
Monthly Flux: N
• TN
• NO3+NO2
• NO3
Monthly Flux: TP
Monthly Flux: Sediment + TP
Monthly Concentration: nutrient
• NO3+NO2
• NO3
• TN
• TP
• Sediment
Monthly Concentration: Sediment
Monthly Concentration: N
• TN
• NO3+NO2
• NO3
Monthly Concentration: TP
Monthly Concentration: Sediment + TP
2
Units
m3/s
104 m3
mm
m3/s
mm
Metric tons
Notes
Parameter 1–14
Parameter 1–14
Parameter 1–14
Parameter 1–14
Parameter 1–14
Parameter 15–39
• TP=OrgP+SolP
• TN=NO3+NO2
+NH4+OrgN
Metric tons
Metric tons
Parameter 15–21
Parameter 22–30
Metric tons
Metric tons
mg/L
Parameter 15–21, 31–39
Parameter 15–21, 31–39
Parameter 15–39
mg/L
mg/L
Parameter 15–21
Parameter 22–30
mg/L
mg/L
Parameter 15–21, 31–39
Parameter 15–21, 31–39
Table S2. Model performance in calibration and validation of water quality
Analyte
Sediment
Calibration
(1997–2006)
Validation
(2007–2013)
All
(1997–2013)
NSE
PBIAS (%)
r2
0.06
21
0.32
−0.50
18
0.06
−0.18
20
0.19
NSE
PBIAS (%)
r2
0.44
2
0.47
−2.54
−75
0.44
0.09
−25
0.27
NSE
PBIAS (%)
r2
0.38
−11
0.40
−0.32
−54
0.44
0.09
−28
0.35
NSE
PBIAS (%)
r2
−0.25
−80
0.27
−2.79
−157
0.27
−1.15
−109
0.22
Metrics
a
TP
TN
NO3+NO2
a
NSE: Nash-Sutcliffe Efficiency; PBIAS: Percent Bias; r2: squared correlation coefficient.
3
Figures
(a)
(b)
4
(c)
(d)
5
(e)
Figure S1. Fractions of land-cover types in 55 subbasins of the Tennessee River Basin. (a)
Forest, (b) Grassland/Pasture, (c) Hay, (d) Other Crops, and (e) Switchgrass. Data source:
Cropland Data Layer (CDL) 2009.
6
Obs
400
Sim
Monthly Runoff (mm)
350
Calibration: (1986–1995)
Validation (1996–2013)
300
250
200
150
100
50
94
19
95
19
96
19
97
19
98
19
99
20
00
20
01
20
02
20
03
20
04
20
05
20
06
20
07
20
08
20
09
20
10
20
11
20
12
20
13
20
14
93
19
92
19
91
19
90
19
89
19
88
19
87
19
19
19
86
0
Year
Figure S2. Comparison between SWAT-simulated (Sim) and USGS (Obs) monthly
runoff in HUC8-06040006
7
Deviation (%) from average value at
HUC6
20
MAP
15
MAR_USGS
MAR_SWAT
10
5
0
06010108
06010204
-5
-10
-15
-20
HUC8
Figure S3. Percentage deviation between two HUC8s (06010108 and 06010204) and
their respective HUC6 units (060101 and 060102) in mean annual precipitation (MAP)
and USGS-estimated and SWAT-simulated mean annual runoff (MAR)
8
Sediment: Monthly Flux (103 kg TSS)
(a)
200,000
Obs: 95% CI
Sim
Calibration (1997-2006 )
150,000
Validation (2007-2013)
100,000
50,000
0
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2012
2013
2012
2013
Year
TP: Monthly Flux (103 kg P)
(b)
5,000
Obs: 95% CI
Sim
4,000
Calibration (1997-2006 )
Validation (2007-2013)
3,000
2,000
1,000
0
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
Year
TN: Monthly Flux (103 kg N)
(c)
25,000
Obs: 95% CI
Sim
20,000
Calibration (1997-2006 )
Validation (2007-2013)
15,000
10,000
5,000
0
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
Year
9
2007
2008
2009
2010
2011
NO3+NO2 :Monthly Flux (103 kg N)
20,000
Obs: 95% CI
Sim
Calibration (1997-2006 )
Validation (2007-2013)
15,000
10,000
5,000
0
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
Year
Figure S4. Comparison between SWAT-simulated (Sim) and LOADEST-estimated (Obs)
monthly nutrient flux through the outlet of the Tennessee River Basin. (a) Sediment, (b)
TP, (c) TN, (d) NO3+NO2. 95% CI denotes the 95% confidence interval on LOADEST
estimates (Obs).
10
(a)
(b)
11
(c)
(d)
12
(e)
(f)
Figure S5. Spatial distribution of SWAT-simulated mean annual loads at 55 subbasins:
(a) runoff (mm), (b) runoff coefficient (RC), (c) sediment loading (kg TSS/ha), (d) TP
loading (kg P/ha), (e) TN loading (kg N/ha), (f) NO3 (kg N/ha)
13