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2013 International SWAT Conference & Workshops - Toulouse, France July 15-19, 2013, Toulouse
Using SWAT to understand the eco-hydrological response to droughts of a dry Mediterranean agro-forested catchment, southern Portugal
Juliana Santos, Júlio Lima, Madalena Moreira, Elsa Sampaio, João Pedro Nunes
Centre for Environmental and Marine Studies University of Aveiro (Portugal)
Institute of Mediterranean Agricultural and Environmental Sciences University of Évora (Portugal)
GOVERNMENT OF THE PORTUGUESE REPUBLIC
ERLAND Project
Guadalupe
Climate change is expected to increase aridity in the Mediterranean rim of Europe, leading to concerns on consequences for water resources availability in a region already under water stress
- Understanding how streamflow availability and vegetation growth have responded to past droughts
- How this might reflect future water availability conditions
Introduction
Study Site: Guadalupe
GUADALUPE:
Agro-forested catchment
Area: 446 ha
Elevation: 260 to 380 meters
Mediterranean inland climate with hot and dry summers and mild winters:
Mean annual precipitation (1973-2012): 533 mm
Mean annual temperature: 15.5ºC
Urban: 0.3 %
Annual Crops: 10.7 %
Olive groves: 2.6 %
Pasture: 5.4 %
Cork/holm oak (>50%) + pasture: 52.9 %
Cork/holm oak (30-50%) + pasture: 28.1 %
Representative of the dry regions of southern Portugal
0
200
400
600
800
1000
1200Total Yearly Rainfall (mm)
The catchment is representative of the streamflow sources for a network of reservoirs in the Évora region which provide water for irrigation and hydroelectric power generation
Hidrometric Station
Guadalupe
Study Site: Guadalupe
Évora city
Discharge:
0
2
4
6
8
10
12
14
16
18
Set/12 Out/12 Nov/12 Dez/12 Jan/13 Fev/13 Mar/13
Flo
w (
mm
)
Date
Flow(stream flow) mm
Soil Moisture:
0
10
20
30
40
50
600
100
200
300
400
500
600
Mai/11 Set/11 Jan/12 Mai/12 Set/12 Jan/13
PP
(m
m)
SWC
(m
m)
Date
SWC_mm
PP_mm
Data Collection:
Study Site: Guadalupe
Climate Data: • Rainfall • Wind Speed • Solar Radiation • Temperature • Relative Humidity
Hidrometric Station
Guadalupe
Évora - Mitra Évora - Cidade
Évora – Cidade Évora
0
200
400
600
800
1000
1200
19
73
19
74
19
75
19
76
19
77
19
78
19
79
19
80
19
81
19
82
19
83
19
84
19
85
19
86
19
87
19
88
19
89
19
90
19
91
19
92
19
93
19
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
Total Annual Rainfall (mm)
Mean = 533 mm
Data Collection:
Climate stations
Study Site: Guadalupe
Évora
2 Eddy covariance flux towers: Carbo Euro Flux 1999-2008
Guadalupe
PT – Mi1 Portugal - Mitra (Evora)
EBF (Evergreen Broadleaf
Forest)
D= 5 km
EBF (Evergreen Broadleaf Forest)
Grassland
D= 11 km
GRA (Grassland)
PT – Mi2 Portugal - Mitra IV (Tojal)
Data Collection:
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.000.00
2.00
4.00
6.00
8.00
10.00
12.00
PP
(m
m)
PET
an
d E
ET (
mm
/day
)
Precipitation (mm) PET_mm/d EET_mm/d_Mitra2
Dry - 2004/2005 Wet - 2005/2006 Wet - 2006/2007 Dry - 2007/2008
PP = 350 mm PP = 632 mm PP = 715 mm PP = 360 mm
ET
Aquifer Recharge
Streamflow Base flow
SW
SWAT Evapotranspiration:
• Soil Moisture • Plant Type • Stage of the plant development • Weather conditions
±
1,000 0 1,000500 Meters
Legend
SwatSoilClass(LandSoils1)
Classes
SROASBL
SROAPmn
SROAPMG
SROAPGD
SROAPG
• HRU definition
1
3
2
4
5
6
8 9
7
10
10 subbasins
Classes of Slope
Soil Type Land Uses
SWAT
±
1,000 0 1,000500 Meters
107 HRUs ±
1,000 0 1,000500 Meters
Legend
SwatSoilClass(LandSoils1)
Classes
SROASBL
SROAPmn
SROAPMG
SROAPGD
SROAPG
National Soil Cartography 1:25000
±
1,000 0 1,000500 Meters
Legend
SwatSoilClass(LandSoils1)
Classes
SROASBL
SROAPmn
SROAPMG
SROAPGD
SROAPG
• Parameterization
±
1,000 0 1,000500 Meters
Legend
SwatSoilClass(LandSoils1)
Classes
SROASBL
SROAPmn
SROAPMG
SROAPGD
SROAPG
SOIL LANDUSES
Coluvisols
Brown Mediterranean Soils - Schists
Brown Mediterranean Soils - Plutonic Rocks
Non-Humic Litholic Soils - Granite (shallow)
Non-Humic Litholic Soils - Granite
Olive groves: 2.6 %
Pasture: 5.4 %
Cork/holm oak (>50%) + pasture: 52.9 %
Cork/holm oak (30-50%) + pasture: 28.1 %
Annual Crops: 10.7 %
Urban: 0.3 %
SWAT
COS 2007 1:25 000
Hidrometric Station
Guadalupe
PT – Mi1
PT – Mi2
0
0.5
1
1.5
2
2.5
3
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Dez
/04
Jun
/05
Dez
/05
Jun
/06
Dez
/06
Jun
/07
Dez
/07
Jun
/08
Dez
/08
LAI (
m2
/m2
)
Ab
ove
-Gro
un
d b
iom
ass
(kg/
m2
)
Above-Ground Biomass (kg/m2) LAI (m2/m2)
0
5
10
15
20
25
30
35
40
0
1
2
3
4
5
6
7
8
SWC
(%
)
PET
/EET
(m
m)
EET(LE)_mm/d
PET_mm/d
SWC 15 cm
MITRA 2 - PASTURE
SWAT Observed Data:
2004/2005 2005/2006 2006/2007 2007/2008
0
0.5
1
1.5
2
2.5
3
LAI (
m2
/m2
)
LAI sim (m2/m2)
LAI obs (m2/m2)
SWAT
PASTURE
Figure: Pasture production curve in rainfed Mediterranean conditions
Autumn Winter Summer Spring
Management Operations - PASTURE
Observed Data: D
aily
Gro
wth
0
0.5
1
1.5
2
2.5
3
LAI (
m2
/m2
)
Date
LAI sim (m2/m2)
LAI obs (m2/m2)
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
EET
(mm
)
EET obs PT-Mi2 (mm)
EET sim (mm)
SWAT
PASTURE - Daily
Preliminary Results:
0
20
40
60
80
100
120
No
v/0
4
Dec
/04
Jan
/05
Feb
/05
Mar
/05
Ap
r/0
5
May
/05
Jun
/05
Jul/
05
Au
g/0
5
Sep
/05
Oct
/05
No
v/0
5
Dec
/05
Jan
/06
Feb
/06
Mar
/06
Ap
r/0
6
May
/06
Jun
/06
Jul/
06
Au
g/0
6
Sep
/06
Oct
/06
No
v/0
6
Dec
/06
Jan
/07
Feb
/07
Mar
/07
Ap
r/0
7
May
/07
Jun
/07
Jul/
07
Au
g/0
7
Sep
/07
Oct
/07
No
v/0
7
Dec
/07
Jan
/08
Feb
/08
Mar
/08
Ap
r/0
8
May
/08
Jun
/08
Jul/
08
Au
g/0
8
Sep
/08
EET
(mm
)
Observed EET (mm) Simulated ET (mm)
SWAT
PASTURE - monthly
Preliminary Results:
R2 = 0.59 NSE = 0.41 PBIAS = 11.1
2004/2005 2005/2006 2006/2007 2007/2008 R2 = 0.85
R2 = 0.66
R2 = 0.36
R2 = 0.84
• Baseflow separation with filter
• Recession curve analysis (Arnold et al, 1995)
Baseflow Separation
AlphaBf= (-1/N) ln(Qn/Qo) N=Number of day Qo=Q at the beginning of the recession Qn=Q at the end of the recession
Parameter Range
mean min max
Alha_Bf (day)
0.09 0.02 0.58
0
2
4
6
8
10
12
14
16
18
Set/12 Out/12 Nov/12 Dez/12 Jan/13 Fev/13 Mar/13
Flo
w (
mm
)
Date
Flow(stream flow) mm
bt (base flow) mm
0
2
4
6
8
10
12
14
16
18
Set/12 Out/12 Nov/12 Dez/12 Jan/13 Fev/13 Mar/13 Abr/13 Mai/13
Observed Flow (mm) Simulated Flow out (mm)
Preliminary Results:
SWAT
Conclusions
• The Evapotranspiration is a very important
parameter to understand the water balance
and can be simulated in SWAT
• The most sensitive parameter to calibrate LAI and evapotranspiration was heat unit
Ongoing:
• Compare the data with satellite data
• Future work will include the upscaling of the model for regional catchments, and its application to evaluate the impacts of climate change scenarios
ET
Aquifer Recharge
Streamflow Base flow
SW
Thank you for your attention
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