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Analysis and flood models for Ljubljana Urban Region Analysis and flood models for Ljubljana Urban Region

Analysis and flood models for Ljubljana Urban Region - PowerPoint Presentation

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Analysis and flood models for Ljubljana Urban Region - PPT Presentation

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

flood land damage buildings land flood buildings damage damages density step residential mitigation hazard maximum curves exposure ratio measures

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Presentation Transcript

Slide1

Analysis and flood models for Ljubljana Urban Region

Elco

Koks & Hans de Moel

Slide2

Brief overview

What is flood risk?Modelling the hazard

Preparing the exposure dataMaximum damages and depth-damage curvesThe damage assessmentApplying mitigation measures

Slide3

Flood risk

Hazard

Exposure

Vulnerability

x

x

=

Risk

Slide4

Modelling the hazard: HEC-RAS

Developed by the US Army Corps of Engineers (USACE)Open access

Allows for modelling river floods

Slide5

Step 1: Digital Elevation Map and Cross-Sections

Slide6

Step 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

Slide7

Step 3: Final steps in HEC-RAS

Slide8

Step 4: The results, 2010 flood simulated

Slide9

Preparing the exposure data: update land-use map

OLD:

NEW:

Slide10

Vulnerability: 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

Slide11

Applying mitigation measures

Raising houses:+25 cm+50 cm

+100 cmBuilding a dike:Notranje

Gorice

Slide12

The results

Slide13

Benefit-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

Slide14

Concluding 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

Slide15

Questions?

Contact details:

Elco.koks@vu.nl