coastal impact on barrier islands: application to praia de ... · this project has received funding...
TRANSCRIPT
This project has received funding from the European Union’s Seventh Programme for Research, Technological Development and Demostration under Grant Agreement No. 603458. This presentation reflects the views only of the authors, and the European Union cannot be considered liable for any use that may be made of the information contained therein.
Coastal Impact on barrier Islands:
Application to Praia de Faro
RISCKIT Final Meeting
Theocharis Plomaritis, Oscar Ferreira and Susana Costas
Regional to Local: Hotspot Tool
• Transform offshore physical parameters into onshore hazard;
• Transform the hazard into impact for selected receptors;
• Surrogate the computationally expensive morphodynamic
simulations within an EWS using a BN
• Incorporate into the tool DRR measures so it can be used by coastal managers as a DSS.
RISCKIT Final Meeting 2017
Study Site – Praia de Faro
RISCKIT Final Meeting 2017
Coastal lagoon system protected by a barrier-island, with sandy shores and dunes.
Storms Hs > 3m; up to 6-7m
Tidal range up to 3.5 m
Storm surge < 1 m
Reduced river input
Early Warning and Decision Support System (EWS/DSS) for use on hot spots.
1. Traditional EWS incorporated in Delft-FEWS that
includes Tides/Surges-Waves-Morphodynamics 2. Store results in Bayesian Network for immediate
evaluation of event impact. 3. Evaluation of Disaster Risk Reduction measures
(DRR)
EWS/DSS
RISCKIT Final Meeting 2017
Model Train for EWS Do
mai
n 1
Dom
ain
2 Domain 3
Surrogated
RISCKIT Final Meeting 2017
FEWS EWS
RISCKIT Final Meeting 2017
• Regional and local
Hazards and relevant model selection (XBeach) Overwash
Coastal/Dune Erosion
Car-park 1996
Protection Works 1990
Camping 1991 C. Sector 1995
Road colapse 1990
Car-park 1990
Study Site – Praia de Faro
RISCKIT Final Meeting 2017
• Historic events Date Duration
(hours)
Wave height (Dir)
Total Water elevation, MSL
(m)
Impact
15/02/1941 24 4.2(SW) 1.8 Inlet opening at Praia de Faro (Ancao Peninsula)
12/01/1969 15 4.3 (SW) 1.1 Major overwash of houses; opening of an inlet and shoreline retreat
11/2/1979 35 7.1 (SW) 1.3 Damages and house destruction at Praia de Faro
13-27/11/1989 40 7 (SW) 1.7
Destruction of houses and seawall
23/01/1996 49 6.5 (SW) 2.31 The entire seawall was damaged at Praia de Faro
02-08/02/1998 28 5.6 (SW) 1.7 Destruction of few houses at Praia de Faro 23-31/12/2009 50 5.8 (SW) 1.3/1.7 7 houses destroyed at Fuzeta
04/01/2010 12 4.7 (SW) 1.6 11 houses destroyed at Fuzeta 15/02/2010 45 4 (SW) 1.56 Strong overwash and breaching (downdrift)
02/03/2010 23 5.2 (SW) 2.15 3 houses destroyed at Praia de Faro
The BN training
RISCKIT Final Meeting 2017
• Synthetic events Hs vs. Tp Hs vs. Surge Hs vs. Duration
Poelhekke et al., 2016 Coastal Engineering
Number of Events
Data Interval Surge (m) Hs (m) Tp (s)
Historic 10 0.31 -0.58 4.5 - 7.1 9.6 - 13.5
Synthetic 30 0.15 – 0.66 3.0 - 7.9 8.1 - 17.4
The BN training
RISCKIT Final Meeting 2017
Synthetic Event Schematisation 1 Simulation for each tidal stage 3x30 =90
The BN training
RISCKIT Final Meeting 2017
DRR measures Three DRR measures have been selected for the Praia de Faro case study (Considering end-users input from interviews): • Beach nourishment (T1) (hazard related, extra modelling)
• House removal (T2) (exposure related)
• Create and/or improve Communication Channels (T3)
(vulnerability related)
RISCKIT Final Meeting 2017
DRR measures • Beach nourishment (T1) (extra modelling )
Nourishment specification were adopted from regional authorities protection plan for Praia de Faro
RISCKIT Final Meeting 2017
DRR measures • House removal (T2)
Areas Selection:
• 4 areas based on exposure characteristics
Receptos Type
• Houses
• Infrastructure
RISCKIT Final Meeting 2017
DRR measures • Channels of Communication (T3)
RISCKIT Final Meeting 2017
Non-primary measures based on two primary measures: • Sandbags
• Constructions on Piles
Model Results Observed Hazard threshold
Hs vs Tp: Good separation of hazard/no hazard event
RISCKIT Final Meeting 2017
Model Results Proxy selection for Praia de Faro:
• Overwash: Max water Flux (cross-shore)
• Erosion: Vertical Erosion in 3 areas
RISCKIT Final Meeting 2017
Bayesian Network Boundary Conditions Hazard
Receptors
Impact Measures
RISCKIT Final Meeting 2017
BN Results • For Hs> 7m and Tp> 14.5sec (Tr ≈ 50 years)
RISCKIT Final Meeting 2017
BN Results : Current Conditions
18 3
79
PotentiallyDamagedDamaged
Safe
• Tr ≈ 50 years
RISCKIT Final Meeting 2017
• Tr ≈ 50 years – Erosion
45
5
50
PotentiallyDamagedDamaged
Safe
BN Results : Current Conditions
RISCKIT Final Meeting 2017
BN Results : Beach Nourishment • Tr ≈ 50 years - Overwash
18 3
79
PotentiallyDamaged
Damaged
Safe
8 0
92
PotentiallyDamaged
Damaged
Safe
Current Conditions Nourishment
RISCKIT Final Meeting 2017
45
5
50
PotentiallyDamaged
Damaged
Safe
2 0
98
PotentiallyDamaged
Damaged
Safe
• Tr ≈ 50 years – Erosion Current Conditions Nourishment
BN Results : Beach Nourishment
RISCKIT Final Meeting 2017
18 3
79
PotentiallyDamaged
Damaged
Safe
12 1
87
PotentiallyDamaged
Damaged
Safe
• Tr ≈ 50 years - Overwash Current Conditions House Removal
BN Results : House Removal
RISCKIT Final Meeting 2017
45
5
50
PotentiallyDamaged
Damaged
Safe
28
2 70
PotentiallyDamaged
Damaged
Safe
• Tr ≈ 50 years – Erosion Current Conditions House Removal
BN Results : House Removal
RISCKIT Final Meeting 2017
18 3
79
PotentiallyDamaged
Damaged
Safe
13 2
85
PotentiallyDamagedDamaged
Safe
• Tr ≈ 50 years - Overwash
BN Results : Channels of Communication
Current Conditions Channels of Communication
RISCKIT Final Meeting 2017
45
5
50
PotentiallyDamaged
Damaged
Safe
41
5
54
PotentiallyDamaged
Damaged
Safe
• Tr ≈ 50 years – Erosion
BN Results : Channels of Communication
Current Conditions Channels of Communication
RISCKIT Final Meeting 2017
18 3
79
PotentiallyDamaged
Damaged
Safe
3 0
97
PotentiallyDamaged
Damaged
Safe
• Tr ≈ 50 years - Overwash
BN Results : Nourishment + House Removal
Current Conditions Nourishment
RISCKIT Final Meeting 2017
Sem SA4 Com SA4
45
5
50
PotentiallyDamaged
Damaged
Safe
1 0
99
PotentiallyDamaged
Damaged
Safe
• Tr ≈ 50 years – Erosion
BN Results : Nourishment + House Removal
RISCKIT Final Meeting 2017
RISCKIT Final Meeting 2017
Concluding remarks • Nourishment is the most effective DRR in reducing the impact
on the houses.
• The use of a BN in EWS could result in significant reduction of the computational effort.
• The method requires a large number of simulation for the initial setup but can result in a very useful tool the event scale protection measures.
• The inclusion of DRR measures makes the proposed tool useful also for long-term decision making process.
RISCKIT Final Meeting 2017
Any questions ?
Thank you
Consequences - Impact (C) From Hazard to Impact - Overwash
House Type 0 1 2 3 4 5 6 7 >7Wood-Framed:
UnanchoredPartial Collapse
Wood-Framed: AnchoredMasonry,
concrete and brick
No Collapse Partial Collapse (if v is also ≥ 2 m²/s)Total Collapse (if v is also ≥ 2 m²/s)
Depth-Velocity Product - vd (m²/s)
No Collapse Total Collapse
No Collapse Partial Collapse Total Collapse
From Hazard to Impact - Erosion Sr-A >= Tp Tp <= Sr-A <=Tpm Tpm <= Sr-A <= Tl Tl <= Sr-A
ErVI None
Low probability of asset collapse:
Disruption caused by preventive evacuation
before and during the event
Medium probability of asset collapse:
Disruption caused bypreventive evacuation as well
asduring and post event
checking/monitoring by civil protection and coastal
management institutions
High probability of collapse:
High disruption and total loss of asset
RISCKIT Final Meeting 2017