Simulating and Evaluating Best Management Practices for Integrated Landscape Management
Scenarios in Biofuel Feedstock Production:
Supporting Information
Miae Ha and May Wu
Argonne National Laboratory, 9700 S. Cass Avenue, Lemont IL 60439
Buffers used two different methods in the U.S. Department of Agriculture’s Soil and Water Assessment
Tool (SWAT). Details are as follows:
A. Trapping efficiency method1
Trapeff = 0.367 (FILTERW)0.2967
(1)
where Trapeff is the fraction of pollutant mass trapped by the filter strip, and FILTERW is the width of the
filter strip (in meters), ranging from 5 to 100 m.
B. Area ratio method2
VFSs were implemented at the HRU level in SWAT. Three parameters were needed as SWAT inputs:
(1) the field area to VFS area ratio (DAFSratio) (the value of 30-60 is recommended), (2) the fraction of the
field drained by the most heavily loaded 10% of the VFS (DFcon), and (3) the fraction of the flow through
the most heavily loaded 10% of the VFS that is fully channelized (CFfrac); all are specified in the HRU (.hru)
file. The area ratio method is modeled in two sections: modest flow densities from a large section and
more concentrated flow from a small section. The method predicts contaminants’ retention under
uniform sheet flow conditions, and also includes nonuniformity in runoff distribution for selected HRUs
on a specified day.
Table S1. SWAT calibration parameters and associated descriptions, ranges, calibrated values for this
study, and references. Potholes and tiles are applied to agricultural lands. References: (A)3, (B)4, (C)5, (D)6,
and (E) baseflow filter program.7
SWAT
Parameter
CN2
Description (SWAT)
DDRAIN
Initial SCS runoff curve number for
moisture condition II
Depth to subsurface drain (mm)
TDRAIN
GDRAIN
POT_FR
Time to drain to field capacity (hour)
Drain tile lag time (hour)
Fraction of HRU area that drains into
Range
30 to
100
0 to
2000
0 to 72
0 to 100
0 to 1
Calibrated
Value
66–85
Reference
1000
(A), (C), (D)
24
96
0.79
(A), (D)
(A), (D)
SWAT
Parameter
POT_TILE
POT_VOL
POT_NSED
DEP_IMP
ERORGN
SURLAG
ESCO
EPCO
FFCB
ICN
CNCOEF
ADJ_PKR
SPCON
SPEXP
RCN
N_UPDIS
CH_COV1
CH_COV2
GW_DELAY
ALPHA_BF
GWQMN
REVAPMN
Description (SWAT)
pothole
Average daily outflow to main channel
from tile flow (mm)
Initial volume of water stored in the
pothole (mm)
Equilibrium sediment concentration in
the pothole (mg/L)
Depth to impervious layer in soil profile
(mm)
Organic N enrichment ratio for loading
with sediment
Surface runoff lag coefficient (days)
Soil evaporation compensation factor
Plant uptake compensation factor
Initial soil water storage expressed as a
fraction of field capacity water content
Curve number (CN) method: 0 –
traditional SWAT method, which bases
CN on soil moisture; 1 – alternative
method, which bases CN on plant
evapotranspiration
Plant ET (evapotranspiration) curve
number coefficient
Peak rate adjustment factor for
sediment routing in the subbasin
Linear parameter for the maximum
amount of sediment re-entrained
Exponent parameter for sediment reentrained in channel
Concentration of nitrogen in rainfall
(mg/L)
Nitrogen uptake distribution parameter
Channel erodibility factor (0 – nonerosive channel, 1 – no resistance to
erosion)
Channel cover factor (0 – channel is
completely protected from erosion by
cover, 1 – no vegetative cover on
channel)
Groundwater delay time (days)
Base flow alpha factor (days)
Threshold depth required for return
flow to occur (mm)
Threshold depth for “revap” or
Range
Calibrated
Value
Reference
0 to 100
39
0 to 100
46
0 to 100
51
0 to
6000
0 to 5
2500
0 to 4
0 to 1.0
0 to 1.0
0.2
1.0
0.62
(A), (C)
(B), (C)
(C)
0 to 1.0
0.95
(C)
0 or 1
1
(A), (C)
0.5 to
2.0
0.5 to 2
0.2
(A), (C)
1.2
(D)
0.0001
to 0.01
1 to 1.5
0.001
(D)
1.1
(D)
0 to 15
4.2
0 to 100
-0.05 to
0.6
40
0.025
(D)
-0.001
to 1
1
(D)
0 to 500
0 to 1
0 to
5000
0 to
46
0.0504
99
(E)
(E)
(D)
(C)
4.7
750
SWAT
Parameter
SHALLST_N
SOL_ORGN
SOL_NO3
Description (SWAT)
percolation to occur (mm)
Initial concentration of nitrate in
shallow aquifer (mg/L or ppm)
Initial organic N concentration in the
soil layer (mg/kg or ppm)
Initial NO3 concentration in the soil
layer (mg/kg or ppm)
Range
1000
0 to
1000
0 to 100
0 to 100
Calibrated
Value
Reference
35
95
50
Table S2. Performance ratings for calibration and validation periods using different statistical methods
(R2, NSE, PBIAS, and RSR) at USGS gauging station #05451210 (SFIR NE of New Providence, Iowa).
Components
Simulation period
Calibration (2000–2005)
Validation (2006–2009)
Calibration (2001–2005)
Nitrate (NO3)
Validation (2006–2009)
Stream flows
(a)
R2
NSE
PBIAS
RSR
0.72
0.85
0.80
0.76
0.67
0.60
0.70
0.71
27.5
38.8
38.8
28.5
0.57
0.63
0.55
0.54
(b)
Figure S1. Monthly observed and simulated results for (a) flow, and (b) nitrate loadings at the USGS
gauging station (#05451210) for the SWAT calibration period (2000-2005 for flow and 2001-2005 for
nitrate loadings) and validation period (2006-2009). (Units: cms - cubic meter per second (flow), mm
(precipitation), and kg (nitrate loadings))
References
1. Neitsch SL, Arnold JG, Kiniry JR, and Williams JR. Soil and water assessment tool theoretical
documentation version 2005. Texas Water Resources Institute; 2005.
2. Arnold J, Kiniry J, Srinivasan R, Williams J, Haney E, and Neitsch S. Soil and Water Assessment Tool
Input/Output Documentation, 2012.
3. Green C, Tomer M, Di Luzio M, and Arnold J. Hydrologic evaluation of the soil and water assessment
tool for a large tile-drained watershed in Iowa. Transactions of the ASABE 49(2):413 (2006).
4. Beeson P, Doraiswamy P, Sadeghi A, Di Luzio M, Tomer M, Arnold J, et al. Treatments of precipitation
inputs to hydrologic models. Transactions of the ASABE 54(6): (2011).
5. Moriasi D, Rossi C, Arnold J, and Tomer M. Evaluating hydrology of the Soil and Water Assessment
Tool (SWAT) with new tile drain equations. J Soil Water Conserv 67(6):513 (2012).
6. Beeson PC, Sadeghi AM, Lang MW, Tomer MD, and Daughtry CS. Sediment delivery estimates in water
quality models altered by resolution and source of topographic data. J Environ Qual 43(1):26 (2014).
7. Arnold J, Allen P, Muttiah R, and Bernhardt G. Automated base flow separation and recession analysis
techniques. Groundwater 33(6):1010 (1995).