Using SWAT to understand the eco-hydrological response to droughts of a dry Mediterranean agro-forested catchment, southern Portugal

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1 GOVERNMENT OF THE PORTUGUESE REPUBLIC 213 International SWAT Conference & Workshops - Toulouse, France July 15-19, 213, 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 Institute of Mediterranean Agricultural and Environmental Sciences University of Aveiro (Portugal) ERLAND Project University of Évora (Portugal)

2 Introduction 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 Guadalupe

3 Study Site: Guadalupe GUADALUPE: Agro-forested catchment Area: 446 ha Elevation: 26 to 38 meters Mediterranean inland climate with hot and dry summers and mild winters: Mean annual precipitation ( ): 533 mm Mean annual temperature: 15.5ºC 12 Total Yearly Rainfall (mm) Representative of the dry regions of southern Portugal Cork/holm oak (>5%) + pasture: 52.9 % Olive groves: 2.6 % Urban:.3 % Annual Crops: 1.7 % Cork/holm oak (3-5%) + pasture: 28.1 % Pasture: 5.4 %

4 Flow (mm) SWC (mm) PP (mm) Data Collection: Study Site: Guadalupe Guadalupe Hidrometric Station Évora city Discharge: Soil Moisture: Flow(stream flow) 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 Date Set/12 Out/12 Nov/12 Dez/12 Jan/13 Fev/13 Mar/ Mai/11 Set/11 Jan/12 Mai/12 Set/12 Jan/13 Date SWC_mm PP_mm

5 Data Collection: Study Site: Guadalupe Climate Data: Rainfall Wind Speed Solar Radiation Temperature Relative Humidity Guadalupe Hidrometric Station Évora Cidade Évora Climate stations Évora - Mitra Évora - Cidade Total Annual Rainfall (mm) Mean = 533 mm

6 PET and EET (mm/day) PP (mm) Data Collection: Study Site: Guadalupe Guadalupe D= 5 km Évora 2 Eddy covariance flux towers: Carbo Euro Flux Precipitation (mm) PET_mm/d EET_mm/d_Mitra2 EBF (Evergreen Broadleaf Forest) PT Mi1 Portugal - Mitra (Evora) D= 11 km PP = 35 mm PP = 632 mm PP = 715 mm PP = 36 mm 2. EBF (Evergreen Broadleaf Forest) 3. PT Mi2 4. Portugal - Mitra IV (Tojal) GRA (Grassland) Grassland 8. Dry - 24/25 Wet - 25/26 Wet - 26/27 Dry - 27/28

7 Evapotranspiration: SWAT ET SW Streamflow Base flow Soil Moisture Plant Type Stage of the plant development Weather conditions Aquifer Recharge

8 HRU definition SWAT 17 HRUs ± 1 subbasins Classes of Slope Legend SwatSoilClass(LandSoils1) Classes Soil Type SROASBL SROAPmn SROAPMG SROAPGD SROAPG 1, 5 1, Meters ± Legend 1, SwatSoilClass(LandSoils1) 1, Classes 5 Meters SROASBL SROAPmn SROAPMG SROAPGD SROAPG Land Uses

9 Parameterization SWAT National Soil Cartography 1:25 SOIL ± LANDUSES COS 27 1:25 Legend Legend SwatSoilClass(LandSoils1) Classes SROASBL SROAPmn SROAPMG SROAPGD SROAPG Coluvisols 1, 5 1, Meters Brown Mediterranean Soils - Schists Brown Mediterranean Soils - Plutonic Rocks Non-Humic Litholic Soils - Granite (shallow) Non-Humic Litholic Soils - Granite SwatSoilClass(LandSoils1) Classes SROASBL SROAPmn SROAPMG SROAPGD SROAPG Cork/holm oak (>5%) + pasture: 52.9 % Olive groves: 2.6 % Urban:.3 % Annual Crops: 1.7 % Cork/holm oak (3-5%) + pasture: 28.1 % Pasture: 5.4 %

10 PET/EET (mm) SWC (%) Dez/4 Jun/5 Dez/5 Jun/6 Dez/6 Jun/7 Dez/7 Jun/8 Dez/8 Above-Ground biomass (kg/m2) LAI (m2/m2) SWAT Observed Data: MITRA 2 - PASTURE Guadalupe Hidrometric Station PT Mi Above-Ground Biomass (kg/m2) LAI (m2/m2) 8 4 EET(LE)_mm/d 7 35 PET_mm/d 6 5 PT Mi SWC 15 cm /25 25/26 26/27 27/28

11 LAI (m2/m2) Daily Growth Observed Data: PASTURE SWAT 3 LAI sim (m2/m2) LAI obs (m2/m2) Autumn Winter Spring Summer Figure: Pasture production curve in rainfed Mediterranean conditions Management Operations - PASTURE

12 EET (mm) LAI (m2/m2) Preliminary Results: 3 SWAT PASTURE - Daily LAI sim (m2/m2) LAI obs (m2/m2) Date EET obs PT-Mi2 (mm) EET sim (mm)

13 Nov/4 Dec/4 Jan/5 Feb/5 Mar/5 Apr/5 May/5 Jun/5 Jul/5 Aug/5 Sep/5 Oct/5 Nov/5 Dec/5 Jan/6 Feb/6 Mar/6 Apr/6 May/6 Jun/6 Jul/6 Aug/6 Sep/6 Oct/6 Nov/6 Dec/6 Jan/7 Feb/7 Mar/7 Apr/7 May/7 Jun/7 Jul/7 Aug/7 Sep/7 Oct/7 Nov/7 Dec/7 Jan/8 Feb/8 Mar/8 Apr/8 May/8 Jun/8 Jul/8 Aug/8 Sep/8 EET (mm) Preliminary Results: SWAT PASTURE - monthly 12 1 Observed EET (mm) Simulated ET (mm) R 2 =.59 NSE =.41 PBIAS = /25 25/26 26/27 27/28 R 2 =.85 R 2 =.66 R 2 =.36 R 2 =.84

14 Flow (mm) Baseflow Separation Baseflow separation with filter Recession curve analysis (Arnold et al, 1995) Flow(stream flow) mm bt (base flow) mm 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 2 Set/12 Out/12 Nov/12 Dez/12 Jan/13 Fev/13 Mar/13 Date Parameter Range Alha_Bf (day) mean min max

15 Preliminary Results: SWAT Observed Flow (mm) Simulated Flow out (mm) Set/12 Out/12 Nov/12 Dez/12 Jan/13 Fev/13 Mar/13 Abr/13 Mai/13

16 Conclusions The Evapotranspiration is a very important parameter to understand the water balance and can be simulated in SWAT ET SW Streamflow Base flow Aquifer Recharge 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

17 Thank you for your attention