Venice – sustainability and the impacts of the flood protection barriers by Paul Linden & Cristina Nasci

1. Venice – sustainability and the
impacts of the flood protection
barriers
Paul Linden & Cristina Nasci
P.F.Linden@damtp.cam.ac.uk, Cristina.Nasci@thetis.it
DAMTP, University of Cambridge
Thetis SpA, Venice
IUGG June 29, 2011 – p.1/35

2. Venice and the Lagoon
The historical city
The industrial port
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3. Historical lagoon
16th Century
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4. Historical lagoon
Vestri 1709
18th Century
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5. Human intervention
19th – 20th Centuries
Reclamation of the rivers Sile and Dese (1925-1930) Reopened fish farms (1907-1928)
Airport (1958) Fish farms (since 1900)
Bridge across the lagoon
railway 1846 highway 1931-1934
First industrial zone (1917)
Lido-Marittima-Marghera Canal (1919-1930)
Second industrial zone (1950-1953)
Lido jetties (1882-1910)
Third industrial zone (1963-1964)
• Malamocco-Marghera Canal (1960-1969)
Fish farms (since 1900) Malamocco jetties (1840-1856)
Romea highway (1965-1968) Chioggia jetties (1910-1934)
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6. Local mean sea level
Eustatic change and subsidence
+ 11 0 0 Total
10 1 reduction
10
9 2 2 in the difference
8 3 between
8
7 4 4 ground
6 5 level
6
5
Eustasy 6 6 and sea
4 7 level
4
3 8 8 (cm)
2 9
2
1 10
10
0.00 livello
0.0 mare nelmedio
del 1908
11
mean Natural 12
12
sea -2
2
subsidence 13
level 3 14
14
in 1908 -4
4 15
5 16
16
-6
6 17
7 18
18
-8
8 Man-induced 19
9 subsidence 20
20
-10
10 21
11 22
22
-12
12 23
– 13 24
perdita totale di quota
del suolo (cm)
1908
1925
1952
1961
1975
1996
1970
-14
14 rispetto al livello medio
15 26
del mare nel 1908
1908 1925 1952 1961 1970 1975 1996
-16
16
trend naturale trend influenzato da sfruttamento artesiano rebound trend attuale
1900
1900 1910
1910 1920
1920 1930
1930 1940
1940 1950
1950 1960
1960 1970
1970 1980
1980 1990
1990
Natural trend Trend caused by the use of artesian wells Rebound Actual trend
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7. Subsidence
Canaletto (1730 ca)
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8. Lagoon habitats
Historical places -
Fish farms Island of Torcello (year 900)
The littorals –
Barrier Island of Pellestrina
Wetlands
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9. Intertidal habitat
Loss due to subsidence and RSLR
1930 1970 2000
168 km2 105 km2 60 km2
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10. Lagoon becomes a bay
Changes to morphology
Mainland Lagoon Sea
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11. Flooding
1 dicembre 2008…156
Flooding
> 140 cm
Increase in the frequency of flooding > 110cm
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12. Storm surge
November, 4th 1966
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13. Flooding
VENICE, LAST HIGH WATER OF 01/12/2008
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14. Adaptation
Range of safeguards
cutting of creeks and
Protected beach nourishment ponds Salt marshes restoration
Pioneer vegetation
Biodiversity: 7
species
Dune management Mobile tidal barriers
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15. Reinforcement of the litoral
Intervention areas
Works underway
Works completed
Eraclea
Works completed Jesolo-Cortellazzo
Cavallino
Beach reconstruction Lido
45 km
Dune restoration
Pellestrina
8 km
Reinforcement of jetty
Sottomarina
11 km
Isola verde
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16. Reinforcement of the litoral
Coastline reinforcement
new groynes
submerged artificial reef S. Pietro in Volta
new beach
lagoon-side embankments
Pellestrina
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17. Pellestrina littoral
before
Before After
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18. Recovery of morphology
Intervention areas
North lagoon
Works completed
Channel dredging Central lagoon
180 km
Reconstruction of mudflats
and salt marshes South lagoon
1,430 hectares
Environmental restoration
of islands
12 islands
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19. Environmental restoration
RE-USE OF SEDIMENTS FOR SALT MARSHES
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20. Environmental restoration
Salt marsh evolution
1 year 9 years
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21. MOSE
Modulo Sperimentale Elettromeccanicon
Location of the Mose Flood Barriers
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22. MOSE
THE MOSE FLOOD BARRIERS
• rows of gates installed in the bed of the inlets; 78 gates (Lido
21+20;Malamocco 19; Chioggia 18)
•"mobile" gates because in normal tidal conditions they are full of
water and rest in their housing structures "caissons" on the
seabed; emission of compressed air empties the gates of water
until they emerge
Each gate
• box-like metal structure lagoon sea
attached to the concrete
caisson in which it is housed by
means of two hinges
• 20 m wide with a variable
height and width according to
the depth of the inlet channel
• average inlet closing time is
from 4 to 5 hours
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23. MOSE
Gates
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24. MOSE
Operation
< 1.10 +1.10 +1.10 +2.00
-14.00 -14.00 -14.00
a b c
< Lagoon Sea >
+1.10 +3.00 +1.10
-14.00 -14.00
d e
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25. MOSE
Hinge system
The male element
raised above
the female element
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26. MOSE
Lido inlet - new construction
The new lay-out lagoon
after realization Cavallino - Treporti
of the Mose System
1
1 Refuge haven with lock
2 Row of gates (Lido -
Treporti) 2
3 New island between the 1
rows of gates 3
4 Row of gate (Lido - S.
Nicolò)
5 New configuration Lido - S. Nicolò 4
of the south bank
6 Breakwater 5
sea
6
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27. MOSE
Lido inlet
titolo Venice
new configuration
of the south bank
new island
refuge haven (sea-side basin lock
- temporary work site for the
gate caissons)
Cavallino - Treporti
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28. Arsenale
Control centre
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29. Arsenale
Restoration
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30. Climate change
Sea level rise
Seattle
observations of mean sea Sa
San Francisco
a c sco
exhibit secular increase of
San Diego
estimates of global sea level
2 cm/decade – consistent with estimates of global SLR
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31. High tide + storms
Winter 1983
Two high tides and two low
daily tides, unequal in
storms amplitude.
Monthly tidal changes
dominated by spring-neap
cycle, with two periods of
relatively high tides
(springs) around full and
new moon. One spring tide
range per month is usually
higher than the other on
this coast.
Th hi h t thl tid
in the winter and summer
months are higher than
High tide levels vary by about 1 m
g y y those in the s
Highest storm-forced level = 28 cm as a result of lunar and
solar declination effects.
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32. Sea level rise predictions
San Francisco hourly sea level
cm
mb
Under projected global warming, such as in the GFDL A2 simulation sea level rises
considerably by 2100, in this scenario by approximately 0.9m.
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33. Venice tides
Punta Salute - December 1997
150
Observed Water Level
Water Level (cm)
100 Predicted Astronomical Tide
50
0
r
-50
-100
5 10 15 20 25 30
150 Day of Month
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34. Vulnerability chart
A tool for assessing vulnerability
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35. Science-based management
Assessment
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36. Science-based management
Assessment
monitoring of physical, chemical properties
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37. Science-based management
Assessment
monitoring of physical, chemical properties
monitoring of biological components
IUGG June 29, 2011 – p.35/35

38. Science-based management
Assessment
monitoring of physical, chemical properties
monitoring of biological components
Decision map for MOSE operation
IUGG June 29, 2011 – p.35/35

39. Science-based management
Assessment
monitoring of physical, chemical properties
monitoring of biological components
Decision map for MOSE operation
impacts on Lagoon
IUGG June 29, 2011 – p.35/35

40. Science-based management
Assessment
monitoring of physical, chemical properties
monitoring of biological components
Decision map for MOSE operation
impacts on Lagoon
public information
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41. Science-based management
Assessment
monitoring of physical, chemical properties
monitoring of biological components
Decision map for MOSE operation
impacts on Lagoon
public information
Re-assessment
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42. Science-based management
Assessment
monitoring of physical, chemical properties
monitoring of biological components
Decision map for MOSE operation
impacts on Lagoon
public information
Re-assessment
commit to regular schedule
IUGG June 29, 2011 – p.35/35

43. Science-based management
Assessment
monitoring of physical, chemical properties
monitoring of biological components
Decision map for MOSE operation
impacts on Lagoon
public information
Re-assessment
commit to regular schedule
include ecosystem services
IUGG June 29, 2011 – p.35/35

44. Science-based management
Assessment
monitoring of physical, chemical properties
monitoring of biological components
Decision map for MOSE operation
impacts on Lagoon
public information
Re-assessment
commit to regular schedule
include ecosystem services
Impacts of climate change on all of the above
IUGG June 29, 2011 – p.35/35

45. Science-based management
Assessment
monitoring of physical, chemical properties
monitoring of biological components
Decision map for MOSE operation
impacts on Lagoon
public information
Re-assessment
commit to regular schedule
include ecosystem services
Impacts of climate change on all of the above
The Venice Conference:
Improving the capacity to assess and to adapt to climate change in urban coastal
regions
September 12 – 15, 2011
Venice, Italy
IUGG June 29, 2011 – p.35/35