Coastal systems under changing
meteo & climate conditions Invited lecture
Prof. Agustín Sánchez-Arcilla ([email protected])
Maritime Engineering Laboratory (LIM/UPC) – Intl. Centre for Coastal Resources Res.
Catalonia University of Technology (UPC) in Barcelona
1.- The case study (CAT coast) 2.- The climatic (decadal) scale: long-term planning 3.- The storm (hourly) scale: risk management 4.- The mid-term (yearly) scale: engineering 5.- The way ahead
High geo- diversity
Coastal fringe width 500 m 6.9% total area CAT - 48% total population CAT
The CATALAN coast case ~ 700 km
Length ~ 700 km Sand beaches ~ 250 km Urban (pocket) beaches ~ 150 km Open beaches ~ 75 km
26 Dec 2008 storms
Limited no. of extremes
Sharp gradients (prediction challenges)
High meteo - diversity The CATALAN coast case ~ 700 km
Riu Ebre
High variability Management signal clearly observable
Cap Tortosa erosion > 1750 m in 43 years (40 m/y) 1957 1973
1984
1989 1993
1998
2000 image
1900 1925 1950 1975 2000tiempo (años)
0
200
400
600
800
1000
caud
al m
edio
anu
al (m
3 /s)
The CATALAN coast case ~ 700 km
Port Balís – Mataró (Nord platja Callao) Trabucador, Delta del Ebre
The CATALAN coast case ~ 700 km
Horizontal variability hindered (by shore rigidization)
Horizontal/Vertical erosion (sediment scarcity)
Decadal (climatic) scale drivers Observations Barcelona (1992-2007) & Valencia (1992-2006) harbours Observed trend: slight decrease of MSL (steadiness)
1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007Year
-60
-40
-20
0
20
40
60
Sto
rm S
urge
Lev
el [c
m]
Storm Surges (Barcelona, 92-07)Storm SurgesLinear Fit
Linear FitY = -8.03E-006 * X - 0.05
BNA
1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006Year
-60
-40
-20
0
20
40
60
Sto
rm S
urge
Lev
el [c
m]
Storm Surges (Valencia, 92-06)Storm SurgesLinear Fit
Linear FitY = -1.7E-005 * X + 1.68
VAL
Trends may vary with interval: MSL (from hind casting) decreases from 1956-1991 and for the whole period but increases for the last decade
Ebre delta
Decadal (climatic) scale drivers
Climatic projections (CIRCE) show a clear increase of SSH for the Spanish Med coast
Simulated SSH at the Catalan/Valencia coast. The continuous line is the average series based on different simulations (1950-2050 and 1950-2060)
1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050
0
0.4
0.8
1.2
1.6
2
Sea
Leve
l Hei
ght
Decadal (climatic) scale drivers
Observed waves off Ebre delta (1990-2006) Slight decreasing trend for both Hmax & Hs
1991 1992 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006Year
0
200
400
600
800
1000
Hm
ax [c
m]
HmaxHmaxLinear Fit
Linear FitY = -0.005 * X + 311.51
1991 1992 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006Year
0
200
400
600
Hsi
g [c
m]
HsHsLinear Fit
Linear FitY = -0.002 * X + 145.57
Decadal (climatic) / yearly (eng) scale drivers
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006year
10
15
20
25
30
35
dura
tion
of s
torm
s [h
]
Mean duration of StormsHs=1.5Hs=2.0
Linear Fit for Hs=1.5mY = 0.01 * X + 0.75
Linear Fit for Hs=2.0Y = 0.25 * X - 484.11
Ave. duration is 20 hrs for Hs=1.5m & 19 hrs for Hs=2.0m Increasing trend for Hs=2.0m
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006year
20
40
60
80
100
120
140
dura
tion
of s
torm
s [h
]
Maximum duration of StormsHs=1.5Hs=2.0
Linear Fit for Hs=1.5mY = 0.92 * X - 1768.43
Linear Fit for Hs=2.0Y = -0.03 * X + 105.25
Max. duration is 73 hrs for Hs=1.5m & 39 hrs for Hs=2.0m Increasing trend for Hs=1.5m
Decadal (climatic) / yearly (eng) scale drivers
Estimated shore-line erosion rates (total horizontal meters) for last century (Recent Past), present decade (Present) and by 2100 (Near Future)
(Sanchez-Arcilla et al 2011)
0102030405060708090
100
Recent Past Present Near Future
Valencia w/No Sub Ebro w/Sub
0102030405060708090
100
Recent Past Present Near Future
Valencia w/No Sub Ebro w/Sub
Decadal scale morphodynamic response (erosion) SLR SLR + storm effects
Meteo Module WRF + ECMWF BCs
Hydrodynamic module SWAN + ROMS
Morphodynamic Module XBEACH + DEM
Indicators Module
PRE-MOS
pre - MOS
December 2008 storm
Storm (high τ) scale drivers
3 areas for calibration
Playa de S’Abanell (Blanes)
Playa del Pont del Petroli (Badalona)
Playa de la Porquerola (Mont-Roig del Camp)
N
Río Tordera
Posidonea
170 µm
700 µm
350 µm
Storm (high τ) scale drivers (2008 storm)
Flooding (water/sand) & damages to promenade
Flooding
No significant damage
Storm (high τ) scale drivers
Hydrodynamics: Hs
Storm (high τ) scale drivers
Morphodynamic module XBEACH Local meshes (grandma → mom → daughter → grand daughter)
Storm (high τ) scale response (2008 storm)
After the storm
Breaching fan deposits (simulated and observed) contribute to maintening the unit (link to longer term scales)
Before the storm
Storm (high τ) scale response (2001 storm)
Storm (high τ) scale response (2001 storm) N
Ave. mid-term shoreline evolution (m/y) for the period 1995-2004 Cell: Port d’ Arenys - Port de Blanes
1950 1960 1970 1980 1990 2000 2010Time (years)
-80
-60
-40
-20
0
20
shor
elin
e di
spla
cem
ent (
m)
Pomareda S
Pomareda N
Blanes
s'Abanell
1950 1960 1970 1980 1990 2000 2010Time (years)
-80
-60
-40
-20
0
20
shor
elin
e di
spla
cem
ent (
m)
Pineda
Pins
St Susana
Malgrat
1950 1960 1970 1980 1990 2000 2010Time (years)
-20
0
20
40
60
shor
elin
e di
spla
cem
ent (
m) Cavalló
Pla
Canet
Llibre Verd Costa Catalana
Mid-term (engineering) scale: observations
24.000 m3/y
10,500 m3/y
Net alongshore transport capacity (m3 / yr) Interval: 1995 / 2006 — Cell: Port d’ Arenys - Port de Blanes Total change: - 20,000 m3 / yr (loss)
5000 m3/y
56.000 m3/y
Llibre Verd Costa Catalana
Mid-term (engineering) scale: calculus
1983 2001
Roca de Gaià
Altafulla beach Tarragona, Spain
Loss > 200.000 m3 in 10 years
Mid-term (engineering) scale: modelling
1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000alongshore distance (m)
40
60
80
100
120
140
160
180
200
acro
ss-s
hore
dis
tanc
e (m
)
Rc / H = +1.25
Rc / H = 0.00
Rc / H = -1.25
300
Computed shoreline with a one-line numerical model (BEACH_1L) behind a detached low-crested breakwater. Salient development as a function of freeboard for oblique wave incidence.
Mid-term (engineering) scale: modelling
The way ahead: predict with uncertainties
Select the “right” time scale
Make explicit the uncertainties
0 50 100 150 200 250 300 350 400 450 500300
350
400
450
500
550
600
650
Z4Weibull.maximum likelihood
Return period (years)
Hs
(cm
)
300000 350000 400000 450000 500000 550000 600000
4500
000
4550
000
4600
000
4650
000
4700
000
20530442054044
20540452055045
2055047
2056045
20560462056047
20560482057048
20580482059048
2060044
2060047
2060049
2061044
20620492063049
2064044
2064047
20640492065049
20660502067051
2068044
2068048
2068051
20680522069052
2070052
2071053
2072044
2072048
2072051
20720532073053
20730542074054
2074055
2074056
2075057
2075058
2075059
2076044
2076048
2076052
20760562076057
20760582076059
2078056
2078059
2080044
2080048
2080052
2080056
5 0 m
PDF from observed data
38.3
69.8
25.7
54.9
32.8
164.0
Net Sl capacity (m3 / any) For 1996 / 2006 Cell Port Arenys - Port BCN
Llibre Verd Costa Catalana
Potential transport ≠ Actual transport
Make explicit the uncertainties
The way ahead: predict with uncertainties
Sl in swash for reflect.beaches
Sl b.c.(s) at end points Sl by-pass b.c.(total/partial)
Uncertainties in BCs
As a function of t-scale
The way ahead: predict with uncertainties