Water resources management in the Pyrenees …Water resources management in the Pyrenees under...

Water resources management in the Pyrenees underenvironmental change

Facts and forthcoming conditions

University of GenevaInstituto Pirenaico de Ecología, [email protected]

J. Ignacio López Moreno; J. María García-Ruiz and Martin Beniston

mailto:[email protected]

Ebro river basin

Ebro river basin:

Area

85.534 Km2

Annual runoff

13408 hm3year-1

Pyrenees: 10.289Km2 (12%) 6204 hm3year-1 (46.2%)

Pyrenees

Importance of Pyrenees in runoff generation


1900 1920 1940 1960 1980 2000

0

500

1000

1500

2000

2500

3000

3500

La Peña

TrempCamarasa

BarasonaTerradets Escales

Canelles

Yesa

Santa Ana

El GradoBúbal

MedianoLanuza

Year

Stor

age

capa

city

(hm

-3)


1900 1920 1940 1960 1980 2000

0

500

1000

1500

2000

2500

3000

3500

La Peña

TrempCamarasa

BarasonaTerradets Escales

Canelles

Yesa

Santa Ana

El GradoBúbal

MedianoLanuza

Year

Stor

age

capa

city

(hm

-3)


Pyrenean reservoirs divert 1947 hm3

yr-1 to irrigate 29.5748 ha, the 38% ofthe irrigated area in the Ebro basin

The 62% of the hydropower productionof the basin is produced in Pyrenees


1957 2002

Land use change

Recent environmental changes can be modifying the hydrological response

Recent environmental changes can be modifying the hydrological response

August, 1912 August, 1998

Land use change

Climatic change

1903 2005

Recent environmental changes can be modyfying the hydrological response

Potential evapotranspiration and precipitation

Precipitation

-1.00

-0.75

-0.50

-0.250.00

0.25

0.50

0.75

1.00

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Spe

arm

an´s

rho

Potential evapotranspiration

-1.00

-0.75

-0.50

-0.25

0.00

0.25

0.50

0.75

1.00


Spe

arm

an´s

rho

Climatic water balance

-1.00

-0.75

-0.50

-0.25

0.00

0.25

0.50

0.75

1.00


Spe

arm

an´s

rho

(Precipitation – Potential evapotranspiration)

Trend statistically significant at 95%

Monthly trends (1950-2000): regional series

Trends in snow accumulation

-4

-2

0

2

4

1950 1960 1970 1980 1990 2000

-4

-2

0

2

4

Water year

Snow

dep

th (-

)Sn

ow d

epth

(-)

March

May

Spearman´s rho: *-0.28

Spearman´s rho: *-0.31

Observed temporal evolution of discharges

In all Pyrenean gauging stations a significant decrease on annual runoff has been detected

Esca river, SigüesA

nnua

l run

off

(Hm

3 )

0

200

400

600

800Veral river, Zuriza

Annu

al ru

noff

(Hm

3 )

0

20

40

60

80

100

120Veral river, Biniés

Annu

al ru

noff

(Hm

3 )

0

50

100

150

200

250

Aragón river, Jaca

Annu

al ru

noff

(Hm

3 )

0

100

200

300

400

500Aragón river, Yesa

Annu

al ru

noff

(Hm

3 )

0

300

600

900

1200

1500

1800Ara river, Torla

Annu

al ru

noff

(Hm

3 )

0

100

200

300

400

500

Cinca river, Lafortunada

Annu

al ru

noff

l (H

m3 )

0

200

400

600

800

1000Ésera river, Graus

Annu

al ru

noff

(Hm

3 )

0

200

400

600

800

1000

1200

1400

Ara river, Boltaña

Annu

al ru

noff

(Hm

3 )

0

200

400

600

800

1000

1200

Río Cinqueta en Molino de Gistaín

Water Year1950 1960 1970 1980 1990 2000

Annu

al ru

noff

(Hm

3 )

0

50

100

150

200

250

300Río N. de Tor en Caldas de Bohí

Water Year1950 1960 1970 1980 1990 2000

Annu

al ru

noffl

(Hm

3 )

0

20

40

60

80

100Río N. Ribagorzana en Pont de Suert

Water year1950 1960 1970 1980 1990 2000

Annu

al ru

noffl

(Hm

3 )

0

200

400

600

800

Water year

1950 1960 1970 1980 1990 2000

Valo

res

esta

ndar

izad

os

-4

-2

0

2

4

Precipitation:april-june

Spearman´s rho:-0.06

Water year

1950 1960 1970 1980 1990 2000

Valo

res

esta

ndar

izad

os

-4

-2

0

2

4

6

Runoff:April-june

Spearman´s rho:** -0.45

Observed trend of spring runoffDecrease of spring discharges

Gauging station Spearman´srho

Veral en Zuriza -.357(*)Veral Binies -.408(**)Aragón Subordan en Javierregay -.559(**)Esca Sigüés -.348(*)Aragón Jaca -.499(**)Aragón Cola de Embalse -.614(**)Ara en Boltaña -0.19Ara Torla -0.22Cinca Escalona -.320(*)Cinca La Fortunada -.353(*)Cinqueta Molino Gistain -0.29EseraEriste -0.28Esera Graus -.403(**)Isabena Capella -.326(*)N Tor Caldes de Boi -.593(**)N Ribagorzana Ginaste -.495(**)N Ribagorz Pont de S. -.400(**)Regional series **-0.45

(*) Correlation is significant at 95%

(**) Correlation is significant at 99%

Gauging station Spearman´srho

Veral en Zuriza -.357(*)Veral Binies -.408(**)Aragón Subordan en Javierregay -.559(**)Esca Sigüés -.348(*)Aragón Jaca -.499(**)Aragón Cola de Embalse -.614(**)Ara en Boltaña -0.19Ara Torla -0.22Cinca Escalona -.320(*)Cinca La Fortunada -.353(*)Cinqueta Molino Gistain -0.29EseraEriste -0.28Esera Graus -.403(**)Isabena Capella -.326(*)N Tor Caldes de Boi -.593(**)N Ribagorzana Ginaste -.495(**)N Ribagorz Pont de S. -.400(**)Regional series **-0.45

(*) Correlation is significant at 95%

(**) Correlation is significant at 99%

Monthly trends (1950-2000): regional seriesAre the observed changes in the climatic variables enough for explaining the intense decrease in runoff ?

Runoff

-1.00

-0.75

-0.50

-0.25

0.00

0.25

0.50

0.75

1.00


Spe

arm

an´s

rho

Precipitation

-1.00

-0.75

-0.50

-0.250.00

0.25

0.50

0.75

1.00


Spe

arm

an´s

rho

Potential evapotranspiration

-1.00

-0.75

-0.50

-0.25

0.00

0.25

0.50

0.75

1.00


Spe

arm

an´s

rho

Res

idua

ls (-

)

-2

-1

0

1

2

Predicted discharge from rainfall and ETo

Residuals

Water year

1960 1970 1980 1990 2000

Dis

char

ge (-

)

-3

-2

-1

0

1

2

3

Observed discharge

Obs disch = 0.53 precipitation – 0.25 EToExplained a 62% of the observed discharge

Climate-runoff relationships

Res

idua

ls (-

)

-2

-1

0

1

2

Predicted discharge from rainfall and ETo

Residuals

Water year

1960 1970 1980 1990 2000

Dis

char

ge (-

)

-3

-2

-1

0

1

2

3

Observed discharge

Obs disch = 0.53 rainfall – 0.25 EToExplained a 62% of the observed discharge

(km2) Forest Shrub Meadows Crops Rock TOTAL

Abandoned fields 258 113 29 0 0

LAND COVER

64%64%

7%7%28%28%

(km2) Forest Shrub Meadows Crops Rock TOTAL

Abandoned fields 258 113 29 0 0

LAND COVER

64%64%

7%7%28%28%Abandoned fields ~30% of the Pyrenean surface

Data from the Upper Aragón river basin

How do the observed hydrological changes affect to the management of thePyrenean reservoirs?

How do the observed hydrological changes affect to the management of the reservoirs?

Run

off (

hm3 )

0

50

100

150

200

250

Apo

rtaci

ón (h

m3 )

0

20

40

60

80

100

120

140

160

Month

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Apo

rtaci

ón (h

m3 )

0

50

100

150

200

250

Month


Run

off (

hm3 )

0

20

40

60

80

100

120

Mediano Barasona

Escales Tremp

1959-1979 1980-1999

Trend of water released to irrigation canals

Canal March April May June July August September AnnualBardenas Canal -0.11 -0.09 0.07 0.42 0.21 0.15 0.42 0.31Cinca Canal -0.01 0.38 0.30 0.63 0.58 0.38 0.08 0.33Aragon and Cataluña Canal 0.77 0.52 0.67 0.73 0.77 0.54 0.42 0.78Statistically significant at 95%


Trend of discharges downstream of the damsReservoir Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep AnnualYesa -0.74 -0.66 -0.39 -0.37 -0.57 -0.76 -0.58 -0.36 -0.59 -0.78 -0.83 -0.67 -0.75El Grado -0.56 -0.54 -0.04 -0.05 0.16 -0.39 -0.62 -0.21 -0.57 -0.57 -0.57 -0.66 -0.63Barasona -0.07 -0.30 -0.45 -0.23 -0.42 -0.53 -0.38 -0.25 -0.53 -0.53 -0.22 -0.04 -0.57Statistically significant at 95%


Storage Outflow Inflow

Group1


Wat

er s

tora

ge (h

m3 )

0

100

200

300

400

500

Dis

char

ge (m

3 s-1)

0

50

100

150

200

Group 2


Wat

er s

tora

ge (h

m3 )

0

100

200

300

400

500D

isch

arge

(m3 s-1

)

0

50

100

150

200

The case of Yesa reservoir

Storage Outflow Inflow

Group1


Wat

er s

tora

ge (h

m3 )

0

100

200

300

400

500

Dis

char

ge (m

3 s-1)

0

50

100

150

200

Group 2


Wat

er s

tora

ge (h

m3 )

0

100

200

300

400

500

Dis

char

ge (m

3 s-1)

0

50

100

150

200

The case of Yesa reservoir

Year

1959

1960

1961

1962

1963

1964

1965

1966

1967

1968

1969

1970

1971

1972

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

Group 1 Group 2

Expected change on annual climatic water balance (mm): 1960/1990 → 2070/2100

Ensembled 6 RCMs

B2 SCENARIOMean change: -244 mm

A2 SCENARIOMean change: -336 mm

Expected change on surface with positive annual climatic water balance (mm):1960/1990 → 2070/2100

Ensembled 6 RCMs

1960-1990(63.975km2)

2070-2100B2 (39.900 km-2)

2070-2100A2 (32.625 km-2)

Expected change on winter precipitation (mm): 1960/1990 → 2070/2100

Ensembled 6 RCMs

B2 SCENARIOMean change: -1.9 mm

A2 SCENARIOMean change: 4.3 mm

Expected change on winter temperature (mm): 1960/1990 → 2070/2100

Ensembled 6 RCMs

B2 SCENARIOMean change: 1.55ºC

A2 SCENARIOMean change: 2.57ºC

Conditions predicted by RCMs for the end of the XXI th century indicates that problems ofwater scarcity could become worse.

Climatic conditions and land-use changes occurred in the last decades lead to a lower capacityof runoff generation of the Pyrenean catchments.Probably the capacity of adapatation of the management of water resources for supplying anincreasing water demand is close to unsustainable levels

Moreover, in Pyrenees there are large areas where revegation processes could continue

Conclusions

Conclusions

Adaptation measurements to face up to a more than previsible future water shortages are requiredi) to favour technologies focussed on water saving and optimisationii) to select the direction of the economical developmentiii) to understand the importance of land management on water resources generation

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