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Global change effects on a Mediterranean river flow in NE SpainEDUARD PLA1, DIANA PASCUAL1, JOAN ALBERT LÓPEZ BUSTINS2, ROBERT SAVÉ3, CARMEN BIEL3, JOAN SERRA3, ROGER MILEGO4, KARIM TAMOH5
1CREAF (Centre for Ecological Research and Forestry Applications) – Autonomous University of Barcelona – 08193 Bellaterra2GC-UB (Group of Climatology – University of Barcelona (UB) – 08001 Barcelona
3DHA-IRTA (Departament d’Horticultura Ambiental – Institut de Recerca i tecnologia Agroalimentàries) – Torre Marimon – 08140 Caldes de Montbui4ETC-LUSI (European Topic Centre – Land Use and Spatial Information) – Autonomous University of Barcelona – 08193 Bellaterra
5GHS-UPC (Grup d’Hidrologia Subterrània – Universitat Politència de Catalunya) – 08034 Barcelona
Study area
Observed trends Next steps
Getting to know ACCUA projectThe interdisciplinary ACCUA project (2008-2011) attempts to identify the main vulnerabilities that affect these systems and propose some adaptation measures at local scale (Catalonia, NE Iberian Peninsula).
The main objectives are (1) to establish land vulnerabilities according to water availability and (2) to propose adaptations addressed to overcome these vulnerabilities. And finally, to suggest recommendations on how to optimize future water uses.
ACCUA project is founded by Obra Social Caixa Catalunya. For further information please do not hesitate to contact us at [email protected] or visit our website www.creaf.uab.cat/accua
Introduction
Climate change is generally accepted as a factor influencing hydrological cycles worldwide. However, these cycles are also affected by other phenomena:
-natural (geomorphological and ecosystem changes, natural climate variations, etc) -human-related (changes of agro-forest uses, developments and settlements, changes on social dynamics, etc).
Within the ACCUA project framework, we have analyzed the historical trends in water balances in a small subbasin in a Mediterranean river (Catalonia, NE Spain).
y = -1.3679x + 2771.1
R2 = 0.1282
0
20
40
60
80
100
120
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
Years
Wat
er f
low
(h
m3/
yr)
y = 0.0638x + 12.266
R2 = 0.5008
10
10.5
11
11.5
12
12.5
13
13.5
14
14.5
15
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
Years
Ave
rag
e te
mp
erat
ure
(ºC
)
y = -2.619x + 1000.5
R2 = 0.0069
400
600
800
1000
1200
1400
1600
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
Years
Pre
cip
itat
ion
(m
m/y
r)
y = 2.6742x + 677.82
R2 = 0.5641
620
640
660
680
700
720
740
760
780
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
Years
PE
T (
mm
)
2,8
20,8
76,2
2000
3,11,9Artificial
1923,6Crops
77,374,2Forest
20051993Fluvià
2,8
20,8
76,2
2000
3,11,9Artificial
1923,6Crops
77,374,2Forest
20051993Fluvià
Fluvià river: Located between the Catalan regions of Garrotxa, Pla de l'Estany and Alt Empordà, the Fluvià catchment presents a high internal diversity of climatic conditions and land uses. The rainy head waters contrasts with the conditions of the coastal alluvial plain. There are protected natural areas. Population pressure is also important in the coastal strip.
400-500
500-600
600-700
700-800
800-900
900-1.000
1.000-1.100
1.100-1.200
1.200-1.300 mm
dry Cataloniawet Cataloniael Fluvià
977 mm
13 ºC
Climatic conditions. Spatial distribution of the annual precipitation mean (1951-1999) for the Fluvià catchment according to the Digital Climatic Atlas of Catalonia (Unitat de Botànica and Departament de Geografia in the Autonomous University of Barcelona). The annual precipitation and temperature mean for the whole catchment is also shown.
Vall d’en Bas subbasin is the headwater of the Fluvià River. The subbasin area is 13 428 ha, mostly forested (62%) with an important agricultural activity (27%). There is a meteorological station (AEMET) and a gauging station at the end of the subbasin (ACA).
We have registered a 60%-reduction of river flow during the period 1984-2008.
We have not detected a significant decrease on rainfall values (which remained relatively stable).
We have measured an increase of 10% in mean annual temperature (+1.2 ºC)
Consequently we have calculated a significant 9%-increment in ETP. This ETP increase could partially explain the reduction of surface water flow in the headwater of the Fluvià River. However, we conclude that there might be other reasons behind this flow decrease, such as modifications on forest and agricultural practices during the recent decades.
We have detected significant land use changes for the period studied: rural abandonment and consequent natural colonization by forest species, reduction of forest management practices, increase of water demand (i.e., increase of irrigated crops, industry development and diffuse housing spreading).
In further research we will analyze the contribution of each factor in water dynamics in order to define adaptive strategies.
Using scenario modelling, on the one hand, we have the trends and climatic projections that help to build the climate change scenarios. On the other hand, land use changes scenarios are also created by means of observed trends and socioeconomic variables.
To integrate everything we use a Basin Model, which interacts also with specific models for forest areas and agriculture.
INTEGRATION MODEL
CLIMATE CHANGE SCENARIOS
LAND USE CHANGE SCENARIOS
FOREST MODEL GOTILWA+
CROP MODEL OF WATER USE
OBSERVED TRENDS + LAND CHANGE MODELLING
OBSERVED TRENDS + GCMs PROJECTIONS
BASIN MODELLING
