Post on 21-Jul-2018
Department of Bioscience
Faculty of Science and Technology
AARHUS UNIVERSITY
Shenglan Lu
SL@DMU.DK
Modelling sediment and phosphorous
transport in a lowland agriculture catchment
1. Department of Bioscience, Aarhus University, Vejlsøvej 25, 8600 Silkeborg, Denmark
2. Department of Hydrology and Hydraulic Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussel, Belgium
Shenglan Lu1 SL@DMU.DK
Joachim Audet1
Hans Thodsen1
Hans Estrup Andersen1
Brian Kronvang1
Ann van Griensven2
with knowledge gained with
field measurements
Department of Bioscience Faculty of Science and Technology AARHUS UNIVERSITY
Shenglan Lu
SL@DMU.DK
2/15
Diffuse P loss in Denmark
Lowland catchments
› Soil erosion & Surface
runoff < 10%
› Surface erosion deposit
in field and buffer zone
Important other source
› Bank erosion
› Tile drains
› Ground water
Phosphorus loss
kgP/ha
National scale Severe field scale
Catchment loss
Leaching
Tile drain
Shallow ground water Shallow ground water
Deep ground water
Tile drain
Leaching
Bank erosion
Soil erosion &
surface runoff
Nielsen, K.S., Krongvang, B., Dalsgaard, K., Bay, K. 2004. Fosfer i landbrugsjord og
drænvand. Vand & Jord. 11:3.115-118.
Department of Bioscience Faculty of Science and Technology AARHUS UNIVERSITY
Shenglan Lu
SL@DMU.DK
3/15
P loss from bank erosion in Odense › Erosion pin plots: 36 streams
› Erosion & Deposition reading
› Extrapolate plots to all streams
› Calculated bank TP = 25%
Catchment TP
› Sediment TP content
› Bank Sediment: 715 ± 311 mgP/kg
› SS:
› Similar P form -> from bank
sediment
› Higher TP content: fine
particle
R² = 0.1625
0
200
400
600
800
1000
1200
1400
1600
0% 20% 40% 60% 80%
TP c
on
ten
t m
gP/k
g
Coarse sand > 250µm content
Department of Bioscience Faculty of Science and Technology AARHUS UNIVERSITY
Shenglan Lu
SL@DMU.DK
4/15
Sediment routing in SWAT: Original (EQN-0) VS Physically based (EQN-1)
› EQN-1: Bank & bed erosion
SS only silt & clay
› TP from Stream
› EQN-0: TP Content * Erosion
› EQN-1: TP Content * Bank Erosion
Department of Bioscience Faculty of Science and Technology AARHUS UNIVERSITY
Shenglan Lu
SL@DMU.DK
5/15
Hypothesis
EQN-1 simulate SS and TP in lowland catchments better
than EQN-0
› Daily flow and mineral P (Same EQN-0 & EQN-1)
› Sediment for EQN-0 & EQN-1
› TP for EQN-0 & EQN-1
Department of Bioscience Faculty of Science and Technology AARHUS UNIVERSITY
Shenglan Lu
SL@DMU.DK
6/15
Catchment Description
Area 486 km2
Elevation 11 – 124 m
Slope 0.01 – 7.29 m/km
Land use Agriculture: 71%, Forest:15%
Soil Type Sandy Loam: 40%, Sandy Clay: 36%
Climate 1999 - 2010
Precipitation: 850 mm Temperature: 28°C in Aug. -10°C in Jan.
Monitoring Kratholm: Daily flow, time proportion SS, PO4 & TP
!
!
!!
!!!!
!
!
!
!
!!
!
!
!
!
!
!
!
!
#0ST 22.35 Kratholm
0 105 km
#0 kratholm
! banklocation
reach
Land Use
AGRL
PAST
FRST
WETN
WATR
URBN
Department of Bioscience Faculty of Science and Technology AARHUS UNIVERSITY
Shenglan Lu
SL@DMU.DK
7/15
Model set up and calibration
› SWAT model
› 29 sub-basin, 429 Hrus, no stream water quality
› Seven 5-year crop rotation, customized crop & manure, tile drainage, point sources, buffer zones, initial P in soil, low MUSLE erosion
› EQN-0 VS EQN-1: same catchment, different stream › EQN-1: measured bulk density, D50, TP content
› Calibration
› Daily flow and annual solute P › Same for EQN-0 & EQN-1
› Daily SS
› Annual particulate P (PP)
Warm up Calibration Validation
Daily Flow 1989-1998 1999-2003 2004-2010
Solute P
Daily SS
PP
1989-1998 1999-2004 2005-2010
Department of Bioscience Faculty of Science and Technology AARHUS UNIVERSITY
Shenglan Lu
SL@DMU.DK
8/15
Flow
0
5
10
15
20
25
30
35
40
45
50
Dai
ly s
tre
am f
low
m3/s
Model
Observe
Validation Calibration
Base flow 45% Tile
drains 37%
Surface runoff 15%
Lateral flow 3%
NSE 0.82
PBIAS -0.5%
NSE 0.79
PBIAS 5%
0
50
100
150
200
250
300
350
400
450
500
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
Wa
ter
Yie
ld m
m/y
r
Observe
Model
Department of Bioscience Faculty of Science and Technology AARHUS UNIVERSITY
Shenglan Lu
SL@DMU.DK
9/15
PO4
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
PO
4 k
gP
/ha
Estimate
Model
0
100
200
300
400
500
PO
4 k
g/d
ay
Model
Observe
Validation Calibration
NSE -0.11
PBIAS 47%
NSE -0.26
PBIAS 43%
Surface runoff 63%
Base flow 27%
Point source 10%
Base flow 45% Tile
drains 37%
Surface runoff 15%
PO4 Flow
Department of Bioscience Faculty of Science and Technology AARHUS UNIVERSITY
Shenglan Lu
SL@DMU.DK
10/15
SS: EQN-0 VS EQN-1
0
20
40
60
80
100
120
140
SS m
g/l
EQN-1EQN-0Observe
Validation Calibration
EQN-0 EQN-1
NSE 0.21 0.23
PBIAS 15% 10%
EQN-0 EQN-1
NSE 0.13 0.14
PBIAS 29% 27%
0
500
1000
1500
2000
2500
3000
3500
4000
4500
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
SS
lo
ad
to
n/y
r
Estimate
EQN-0
EQN-1
-500
0
500
1000
1500
2000
2500
EQN-0 EQN-1
Ave
rag
e a
nn
ua
l S
S lo
ad
to
n/y
r
Surface Erosion
Bed erosion
Bank erosion
Deposision
Department of Bioscience Faculty of Science and Technology AARHUS UNIVERSITY
Shenglan Lu
SL@DMU.DK
11/15
!.
!.
!.
!.
!.
!.
!.
!.
!.
!.
!.
!.
!.
!.
!.!.
!.
!.
!.
!.
!.
!.
!.
!.
!.
!.
!.
!.
!.
!.
!.!.
!.
!.
!.
0 105 km
Bank Erosion
› SWAT: some
distribution
› Bank erosion:
site specific
Obs Erosion mm
!. -155.160920 - -87.962500
!. -87.962499 - -36.028986
!. -36.028985 - -14.888889
!. -14.888888 - 0.000000
!. 0.000001 - 11.839080
!. 11.839081 - 40.033333
!. 40.033334 - 97.786667
EQN-1 erosion ton
-1375.120000 - -1329.690000
-1329.689999 - -587.260000
-587.259999 - -164.100000
-164.099999 - 0.000000
0.000001 - 185.322100
185.322101 - 519.086000
519.086001 - 1504.887549
Department of Bioscience Faculty of Science and Technology AARHUS UNIVERSITY
Shenglan Lu
SL@DMU.DK
12/15
PP: EQN-0 vs EQN-1
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
1999 200020012002 2003200420052006 200720082009 2010
PP
kg
P/h
a
Estimate
EQN-0
EQN-1
0
500
1000
1500
2000
2500
3000
3500
4000
4500
199920002001200220032004200520062007200820092010
SS
lo
ad
to
n/y
r
Estimate
EQN-0
EQN-1
-4000
-2000
0
2000
4000
6000
8000
10000
Bank erosion Deposision Sediment Out
Ave
rag
e a
nn
ua
l s
ed
ime
nt
bu
dg
et
ton
/yr
EQN-1 Silt&Clay (TSS)
EQN-1 Other particles
0.000
0.050
0.100
0.150
0.200
0.250
0.300
EQN-0 EQN-1
Ave
rag
e a
nn
ua
l P
P k
gP
/ha
Surface runoff
Point Source
Bank erosion
Department of Bioscience Faculty of Science and Technology AARHUS UNIVERSITY
Shenglan Lu
SL@DMU.DK
13/15
TP: EQN-0 vs EQN-1
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
TP
kg
P/h
a
Estimate
EQN-0
EQN-1
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
1999200020012002 200320042005 2006200720082009 2010
PP
kg
P/h
a
Estimate
EQN-0
EQN-1
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
PO
4 k
gP
/ha
Estimate
Model
0.000
0.050
0.100
0.150
0.200
0.250
0.300
0.350
0.400
0.450
0.500
EQN-0 EQN-1 Estimate
Ave
rag
e a
nn
ua
l T
P k
gP
/ha
Bank erosionSurface runoffBase flowPoint source
Department of Bioscience Faculty of Science and Technology AARHUS UNIVERSITY
Shenglan Lu
SL@DMU.DK
14/15
0
100
200
300
400
500
600
700
800
900
1000
Oct
-99
Dec
-99
Feb
-00
Ap
r-0
0
Jun
-00
Au
g-0
0
Oct
-00
Dec
-00
Feb
-01
Ap
r-0
1
Jun
-01
Au
g-0
1
Oct
-01
Dec
-01
Feb
-02
Ap
r-0
2
Jun
-02
Au
g-0
2
Oct
-02
Dec
-02
Feb
-03
Ap
r-0
3
Jun
-03
Au
g-0
3
Oct
-03
Dec
-03
Feb
-04
Ap
r-0
4
Jun
-04
Au
g-0
4
TP k
gP/d
ay
EQN-1
EQN-0
Observe
Daily TP: EQN-0 VS EQN-1
EQN-1:
› Higher peaks
› Follow recession
EQN-0 EQN-1
NSE 0.15 0.63
PBIAS 61.9% 25.3%
Department of Bioscience Faculty of Science and Technology AARHUS UNIVERSITY
Shenglan Lu
SL@DMU.DK
15/15
CONCLUSION
› Daily flow: very good in lowland catchment
› PO4 load: lack input from tile drains
› TSS: EQN-1 higher peaks & lower low concentrations
than EQN-0
› TP: EQN-1 better than EQN-0 in lowland catchments
Thanks for your attention!
Questions?
Department of Bioscience Faculty of Science and Technology AARHUS UNIVERSITY
Shenglan Lu
SL@DMU.DK
16/15
Daily SS: EQN-0 VS EQN-1
0
10
20
30
40
50
60
70
80
Oct
-01
Dec
-01
Feb
-02
Ap
r-0
2
Jun
-02
Au
g-0
2
Oct
-02
Dec
-02
Feb
-03
Ap
r-0
3
Jun
-03
Au
g-0
3
Oct
-03
Dec
-03
Feb
-04
Ap
r-0
4
Jun
-04
Au
g-0
4
SS m
g/l
EQN-0EQN-1Observe
0
20
40
60
80
100
120
140
Oct
-06
Dec
-06
Feb
-07
Ap
r-0
7
Jun
-07
Au
g-0
7
Oct
-07
Dec
-07
Feb
-08
Ap
r-0
8
Jun
-08
Au
g-0
8
Oct
-08
Dec
-08
Feb
-09
Ap
r-0
9
Jun
-09
Au
g-0
9
SS m
g/l
EQN-0EQN-1Observe
Equally bad
EQN-1:
› Higher peaks
› Lower low
concentration
EQN-0 EQN-1
NSE 0.21 0.23
PBIAS 15% 10%
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