Date post: | 06-Aug-2015 |
Category: |
Science |
Upload: | delftsoftwaredays |
View: | 27 times |
Download: | 1 times |
Storm-induced coastal risks at the Tordera delta under different climate scenarios
José A. Jiménez, Marc Sanuy,Agustín Sánchez-ArcillaAgustín Sánchez-Arcilla
Laboratori d’Enginyeria Marítima. Universitat Politécnica de Catalunya · BarcelonaTechBarcelona, Spain
Introduction
Storm-induced inundation and erosion are two of the most frequent coastal hazards affecting worldwide coastlinesfrequent coastal hazards affecting worldwide coastlines.
Associated coastal risks are likely to increase in the future due to changes in climate forcing which should require a re-evaluation of coastal disaster risk reduction strategies.
To develop a methodology to assess the influence of SLRTo develop a methodology to assess the influence of SLR on storm-induced coastal flooding & erosion taking into account the SLR-induced coastal response.
CC-induced effects in the forcing
steady (no change in storminess)
∆R
Ocean
∆R
dc
R
Surge Level
QovRu
storm surge level
Barrier S
Mean Water Level
SMWLincreasing
(SLR)(SLR)
Static approach
(source: USGS)
but ….. Only valid if the coast is rigid/passive (e.g. revetment, rocky)
Erosion hazard
Magnitude of erosion hazard not affected.
Narrow beaches Larger/greater exposure Higher risk
2
4
6
2
4
6
-4
-2
0
elev
ació
n (m
)
-4
-2
0
elev
ació
n (m
)
10
-8
-6
10
-8
-6
50 75 100 125 150 175 200 225 250 275 300 325 350 375 400distancia (m)
-10
50 75 100 125 150 175 200 225 250 275 300 325 350 375 400distancia (m)
-10
Inundation hazard (I)Long time series (> 40 y) ofwave and water level time
8
Ru Total water level
time series
wave and water level timeseries
Stockdon’2006
7
time series
P O T
5
6P.O.T.
Select thesholde.g. quantile 0.995
4
R
2
3Ru
Total water levelextreme events
1 10 100
Return period (years)
ExtremeExtremeProb. Function fitting
GPD
Inundation hazard (II)Rc
Q
MWL
tanβTi,Hi,
OvertoppingHedges and Reis (1998)coefficients modified by Reis et al. (2008)y ( )Function of Ru (wave-induced forcing) and Rc (coastal characteristics)
Rc = 1.5 m
Rc = 2.0 m
Rc = 2.5 m
Inundation hazard (IV)
SLR – induced changes
No changes in forcing (waves and storm-surge) – steady Ru
Changes in overtopping due to decreasing freeboard due to Changes in overtopping due to decreasing freeboard due to changes in MWL . Beach profile adaptation to SLR
Ch i b h fil Changes in beach profile –Bruun rule + accommodationspace availability
Changes in floodwater
Changes in inundation
4612200
4612400
4612200
4612400
4612200
4612400
4612200
4612400
4611800
4612000
4611800
4612000
4611800
4612000
4611800
4612000
4611400
4611600
4611400
4611600
4611400
4611600
4611400
4611600
4611000
4611200
4611000
4611200
4611000
4611200
4611000
4611200
4610600
4610800
4610600
4610800
4610600
4610800
4610600
4610800
479500 480000 480500 481000 4815004610400
479500 480000 480500 481000 4815004610400
479500 480000 480500 481000 4815004610400
479500 480000 480500 481000 4815004610400
Concluding Remarks
The use of traditional static approach to account changes in storm The use of traditional static approach to account changes in storm-induced inundability due to SLR overpredicts the induced effects and it must be considered as the worst case scenario.
Including the SLR-induced coastal response (quasi-dynamic approach) reduce the effects, specially in areas with a large accommodation space .
In developed coasts, this reduction is more detectable at shorter time horizons, when SLR-induced retreat is small in comparison with the , paccommodation space.
In relative terms the effects are more detectable for high probability stormsIn relative terms, the effects are more detectable for high probability storms (smaller Tr).
Erosion risk is affected by reducing the capacity of protection provided by Erosion risk is affected by reducing the capacity of protection provided by the beach.
Acknowledgements
Wave data Puertos del Estado(Spanish Ministry of Public Works)(Spanish Ministry of Public Works)
Topographic data Institut Cartogràfic i Geologic de Catalunya)
Funded by
EU FP7 Research projects
RISC-KIT (603458) http://www risckit eu/RISC KIT (603458)
RISES-AM (603396)
http://www.risckit.eu/http://www.risesam.eu/