Global change effects on a Mediterranean river flow in NE Spain EDUARD PLA 1, DIANA PASCUAL 1, JOAN...

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 accua@creaf.uab.cat 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