1

2

Guillem Chust&

K-egokitzen core team: Á. Borja, P. Liria, A. Caballero, J. Franco, X. Irigoien

AZTI-Tecnalia, Marine Research Division

The impact of the sea level rise on Basque coastal habitats

throughout the 21st century

May 6th, 2011

© AZTI-Tecnalia 3

K-EGOKITZEN Project

“Climate Change in the Basque Country: Impacts and

adaptation”

Work Package : Coastal Zones

Period: first phase 2007-2009, 2nd phase: 2010-2012Goal: to assess the impacts of climate change and to propose adaptation measures for the Basque coast Financed by Basque Country GovernmentProject leader: Labein-Tecnalia

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Specific objectives :

I. Evidences of climate changeII. Climate scenariosIII. Impacts and vulnerabilityIV. Adaptation strategies

Coastal zones and elements:

1. Beaches, dunes and estuaries2. Habitats and biodiversity 3. Coastal infrastructures and urban areas

Objectives

Basque coast

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• Global mean sea-level rate: 1.8 ± 0.3 mm/yr between 1950 and 2000 (Church et al., 2004), with large spatial variability at regional scales

Linear trends in mean sea level (mm yr–1) for1955 to 2003 based on the past sea levelreconstruction with tide gauges and altimetrydata (IPCC 4AR, 2007)

Global sea level trends

SLR = Thermal expansion + ice melting

© AZTI-Tecnalia 6Year

1940 1960 1980 2000

Mea

n se

a le

vel (

mm

)

6800

6850

6900

6950

7000

7050

7100St. Jean de LuzBilbao

Mea

n se

a le

vel (

mm

)6800

6850

6900

6950

7000

7050

7100

7150

Santander

Sea-level measurements (tide gauge) along the Basque coast and nearby records

Santander

St Jean Luz

Bilbao

2.08 ± 0.33 mm yr-1

2.09 ± 0.42 mm yr-1

2.99 ± 1.08 mm yr-1

Chust et al. 2009. Estuarine, Coastal and Shelf Science 84:453-462

Regional sea level measurements

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Location Method Time period

Rate and error (mm yr-1)

Reference

Vigo Tide gauge 1943 - 2001 2.91±0.09 Marcos et al. (2005) La Coruña Tide gauge 1943 - 2001 2.51±0.09 Marcos et al. (2005) Santander Tide gauge 1943 - 2001 2.1 Marcos et al. (2005) Brest Tide gauge 1890 - 1980 1.3±0.5 Wöppelmann et al.

(2006) Brest Tide gauge 1980 - 2004 3.0±0.5 Wöppelmann et al.

(2006) Newlyn Tide gauge 1915 - 2005 1.77±0.12 Araújo and Pugh

(2008) St. Mary’s Tide gauge 1968 - 2006 1.73±0.52 Haigh (2009) Open water of Bay of Biscay

Satellite altimeters and Tide gauge

1993 - 2002 3.09±0.21 Marcos et al. (2007)

Open water of Bay of Biscay

Satellite altimeters 1993 - 2005 2.7 Caballero et al. (2008)

Basque coast Foraminifera-based transfer

functions

20th century 2.0 Leorri et al. (2008)

Basque coast Foraminifera-based transfer

functions

20th century 1.9 Leorri and Cearreta (2009)

Sea level rise within the Bay of Biscay

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Future Climate Scenarios

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San Sebastián

⇒ Mean Sea Level Rise (thermal expansion + ice melting)

⇒ Storm surges (meteorological tides)

⇒ Wave extreme events (tides + run-up)

Deusto, 10 September 2010

Sea level

variability

Regional climate scenarios for the 21st century

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1. Column waterintegration

2. Model selection

SRES A1B

WCRP Tª oceanSalinity

Sea level

Chust et al. 2010. Estuarine, Coastal and Shelf Science 87:113-124

∫−=01H

dpg

TSL α

Projections for the thermosteric sea level rise

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Year

1940 1960 1980 2000 2020 2040 2060 2080 2100

Sea

leve

l ris

e (c

m)

-20

0

20

40

60

St. Jean de Luz Santander Bilbao SRES A2 + MinMelt SRES A1B + MaxMelt

Thermal expansion + ice melting (4 to 20 cm) => 29 to 49 cm

Chust et al. Climate Research (In Press)

Mean Sea Level Rise for the bay of Biscay

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High-resolution cartographic data

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• LIDAR-based Digital TerrainModel (DTM)

– Spatial resolution: 1 x 1 m– Vertical accuracy: 15 cm

• Habitat maps fromortophotography:

– Spatial res.: 25 x 25 cm

High-resolution airborne data

(M.A. Ortiz)

LIDAR: laser altimeter

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Bilbao I

PMA

NMMB

NMMA

BMA Cero Puerto

0,337 m (REDNAP2008)

2,063 m (REDNAP2008)

4,94

0,11

Alicante

Bilbao

LiDAR validation with GPS and MSL references

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Expected impacts from sea level rise

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Mean Sea LevelTiderange:4.94 m

SLR: +0.49 m

Tides

KOSTASystem

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Gipuzkoa

Area affected:• 110 hectares • 50% in estuaries

Flood risk map: Sea level rise of 49 cm

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Flood risk map for urban areas

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Futuro

Bruun rule

Retreat in beach width

25%

40%

Flood risk map for sandy beaches

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Flood risk map for saltmarshes

Saltmarshes and crops

Profile (pixels)

0 100 200 300

Height (A

MS

L)

0

2

4

6

8

10

MAHT + SLR MAHT OMEHT OMEHT + SLR

SaltmarshWall

Crops

A

B

FitzGerald, 2008

Within the Basque estuaries, an accretion rate of 3.7 mm yr−1 during the 20th c. (Leorri et al., 2008) suggests that marshes are potentially able to adjust to the projected SLR rates …

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… except for “Coastal squeeze”

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Urbanización de la costa

1956

2002

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2004

Urbanización de la costa

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Natural changes(38 ha)

Anthropogenicchanges (98 ha)

Changes due to sea level rise (3 ha)

71%

27%

2%

Trasnformaciones en el litoral gipuzkoano entre 1954 a 2004

Chust et al. 2009. Estuarine, Coastal and Shelf Science 84:453-462

⇒ Barriers willconstrain thenatural migrationof species

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Bathymetric LiDAR and the impacts of sea

level rise on coastal biodiversity

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Topographic LiDAR

(NIR: 1064 nm)

Bathymetric LiDAR

(Green: 532 nm)

Bathymetric LiDAR (Hawk Eye MK II)

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Digital Elevation Model of the Oka estuary

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Intertidal area

Subtidal area

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Field work: Zostera noltii distribution

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Profile (m)

0 200 400 600 800 1000 1200

Hei

ght (

m)

-4

-2

0

2

4

6

Neap Tide

High Tide

+ Sea level rise

+ Sea level rise

Phra

gmite

s

Junc

us

Mar

shes

Spar

tina

Gra

cila

ria

Zost

era

Mudflats

Marshes

Main channel

Fixedboundary

(A) (B)

Zostera noltii

Estuaries in a Changing Climate5-8 Pril 2011, Porto, PortugalTide zonation of intertidal species communities

Chust et al. 2010 Estuarine, Coastal and Shelf Science 89: 200-213

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Zostera noltii

2008 2100

Z. noltii habitat suitability

- 40%

Chust et al. Climate Research (In press)

HabitatSuitability:

0-33 �

33-67 �

67-100�

Impacts on seagrasses: Habitat suitability modelling

• Reduction of habitat suitability for Zostera noltii• Only present in 3 of the 12 estuaries• Geneflow among estuarine populations is very low

Zostera noltii seagrass is highly vulnerable to sea level rise

⇒⇒⇒⇒

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Flood risk from storm surges

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Sea level = Astronomic Tide + Meteorological Tide

Meteorological Tide depends on wind and pressure

Sea level expected by 2050-2100 as a consequence of 50-yr return level

Sea level rise + Storm surge ( marejada ciclónica ) ⇒ 85 cm above Maximum Astron. tide

Flood risk from storm surges

Deusto, 10 September 2010

Sea level ~ Maximum Astronomic tide

IMEDEA-CSIC

Marcos et al. (submitted)

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Flood risk map expected by 2050-2100 as a consequence of 50-yr return level Sea level rise + Storm surge ⇒ 85 cm above Maximum Astron. tide

⇒ 363 ha are under risk of flooding, of which 54% correspond to artificial landMarcos et al. (submitted)

Flood risk from storm surges

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Flood risk from wave extreme events

13 de marzo de 2008

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Extreme wave (wave height) flood level expected for a 50-yr return period

FL: Flood level

TL: Tide level

RU: wave run-up (ascenso de la lámina de agua sobre el perfil de la costa debido a la rotura del oleaje)

AT: Astronomic tide

MT: meteorological tide

RU0: theoretical run-up

Liria et al. 2011 Journal of Coastal Research

RUMTATRUTLFL ++=+=

Extreme wave events: methodology

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Extreme wave events Sea-level rise

Liria et al. 2011 Journal of Coastal Research

Flood risk areas

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Inundation and floods dueto:

• sea level rise (29-49 cm)• storm surges (+85 cm)• extreme wave events

⇒ 250 ha of the Basque coast is at risk of flood, concentrated within the estuaries (~50%)

⇒ Retreat of beaches on 25-40% of width

⇒ The habitat of intertidalspecies and salt-marshescan be reduced

Scenarios Impacts Adaptations

• Maintenance andrebuilding of coastalinfrastructures

• Revision of drainagesystems

• To promote coastal resilience such as protection, regeneration of dune plants and intertidal species and wetlands, sand stabilization, establish buffer zones

Conclusions and Adaptation strategies

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Acknowledgements

• Gobierno Vasco (ETORTEK, proyecto K-Egokitzen I & II)• Ministerio de Medio Ambiente y Medio Rural y Marino, Gobierno de España

(Proyecto Ref.: 0.39/SGTB/2007/4.1)• Agencia vasca del Agua (URA), Gobierno Vasco, proyecto « Inundabilidad de los

estuarios vascos »• Diputación Foral de Gipuzkoa• K-egokitzen participants: Ángel Borja, Ainhoa Caballero, Pedro Liria, Javier Franco,

Xabier Irigoien, Marina Chifflet, Ibon Galparsoro, Carlos Hernández, Manuel González, Marta Revilla, Almudena Fontán, Víctor Valencia, Joxe. M. Garmendia

Climate Change Documentary: www.vimeo.com/13292409

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References

• Chust, G., Á. Borja, P. Liria, I. Galparsoro, M. Marcos, A. Caballero, and R. Castro (2009). Human impacts overwhelm the effects of sea-level rise on Basque coastal habitats (N Spain) between 1954 and 2004. Estuarine, Coastal and Shelf Science 84:453-462.

• Chust, G., A. Caballero, M. Marcos, P. Liria, C. Hernández, and Á. Borja. 2010. Regional scenarios of sea level rise and impacts on Basque (Bay of Biscay) coastal habitats, throughout the 21st century. Estuarine, Coastal and Shelf Science 87:113-124.

• Chust, G., Grande, M., Galparsoro, I., Uriarte, A. & Borja, A. 2010. Capabilities of the bathymetric Hawk Eye LiDAR for coastal habitat mapping: a case study within a Basque estuary. Estuarine, Coastal and Shelf Science89: 200-213.

• Valle, M., Borja, Á., Galparsoro, I., Garmendia, J.M., Chust, G., 2010. Estudio del hábitat idóneo para Zostera noltii y su modificación bajo un escenario de cambio climático en el estuario del Oka. Revista de Investigación Marina 17(1): 1-12.

• Chust G, Borja A, Caballero A, Liria P, Marcos M, Moncho R, Irigoien X, Saenz J, Hidalgo J, Valle M, Valencia V. Climate Change on the coast and pelagic environment in the south-eastern Bay of Biscay. Climate Research (In press). DOI: 10.3354/cr00914.

• Valle, M, Á. Borja, G. Chust, I. Galparsoro, JM Garmendia. Modelling suitable habitat for Zostera noltii within the Oka estuary (Basque Country), using Ecological Niche Factor Analysis. (Submitted to ECSS).

• Liria, P., Chust, G., Epelde, I., and Caballero, A., 2011. Extreme Wave Flood-Risk Mapping Within the Basque Coast. Journal of Coastal Research, SI 64.

Thank you for your attention!