Elco Koks amp Hans de Moel Brief overview What is flood risk Modelling the hazard Preparing the exposure data Maximum damages and depthdamage curves The damage assessment Applying mitigation measures ID: 807650
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Slide1
Analysis and flood models for Ljubljana Urban Region
Elco
Koks & Hans de Moel
Slide2Brief overview
What is flood risk?Modelling the hazard
Preparing the exposure dataMaximum damages and depth-damage curvesThe damage assessmentApplying mitigation measures
Slide3Flood risk
Hazard
Exposure
Vulnerability
x
x
=
Risk
Slide4Modelling the hazard: HEC-RAS
Developed by the US Army Corps of Engineers (USACE)Open access
Allows for modelling river floods
Slide5Step 1: Digital Elevation Map and Cross-Sections
Slide6Step 2: The discharges (in meters per second)
Return period
Ljub1
Ljub7Podl1
Zorn1boro1
iska1iz_side1
izic1
grad1
Suji1
'
vhrnika
'
'
moste
'
'razor'
'
drenov
'
'
borovnica
'
'
iska
'
'ig1'
'
zelimlje
'
'
dvor
'
'
razori
'
2
13
55
13
2
10
28
10
14
15
6
10
27
108
23
4
22
53
15
26
34
14
25
31
126
27
4
27
62
16
31
42
19
50
34
136
30
5
30
68
17
34
47
22
100
37
144
32
5
33
74
17
37
52
25
250
39
153
35
6
36
80
17
40
57
28
500
41
158
37
6
38
84
17
42
61
31
Slide7Step 3: Final steps in HEC-RAS
Slide8Step 4: The results, 2010 flood simulated
Slide9Preparing the exposure data: update land-use map
OLD:
NEW:
Slide10Vulnerability: maximum damages and depth-damage curves
Based on JRC study from 2007: curves and maximum damages were tailored to country level.
Land-use
class
Max Damage (per square meter)
High-density
residential: land
25
High-density
residential: the buildings
400
Low-density residential: land
10
Low-density residential: the buildings
400
Industrial or commercial:
land
20
Industrial or
commercial:
the buildings
300
Road and rail networks and associated land
8.34
Airports
10.58
Construction sites
76.73
Green urban areas
59.01
Sport and leisure facilities
57.57
Non-irrigated arable land
0.43
Permanently irrigated land
0.42
Vineyards
0.4
Fruit trees and berry plantations
0.38
Pastures
0.4
Annual crops associated with permanent crops
0.33
Complex cultivation patterns
0.37
Land principally occupied by agriculture, with significant areas of natural vegetation
0.25
Agro-forestry areas
0.29
Slide11Applying mitigation measures
Raising houses:+25 cm+50 cm
+100 cmBuilding a dike:Notranje
Gorice
Slide12The results
Slide13Benefit-cost analysis
Cost-benefit ratio of dike at Notranje
is > 2Elevating existing buildings has very low ratio (0.005)Elevating new buildings has a much higher ratio but is not everywhere > 1
Slide14Concluding remarks
The model is able to model the flood and its consequences
BUT: maximum damages and curves should be tailored more to Slovenian characteristics.With such models, many more adaptation and mitigation measures
can be evaluated
Slide15Questions?
Contact details:
Elco.koks@vu.nl