Flood hazard mapping - NVEFlood hazard mapping Rengifo Ortega Section for geoinformatics Norwegian...
Transcript of Flood hazard mapping - NVEFlood hazard mapping Rengifo Ortega Section for geoinformatics Norwegian...
Flood hazard mappingRengifo Ortega
Section for geoinformatics
Norwegian Water Resources and Energy Directorate
People need space, so do rivers
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Norwegian Water Resources and Energy Directorate
… so do people
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Norwegian Water Resources and Energy Directorate
Historical overview
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Flood marks 1675- 1995
1789 largestflood in Norway
1995 Secondlargestflood, Glomma River
1997 National MappingProgram
Since then,125 rivers have been mapped, covering about 1250 km river length
Norwegian Water Resources and Energy Directorate
Overall responsibility
■ Prevention ofdamages causedby flood
■ Assist local authorities to■ Identify hazard■ Analyse and evaluate the risk
associated with that hazard and■ Determine appropiate ways to eliminate or control the hazard
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Norwegian Water Resources and Energy Directorate
Mapping Plan
■ Areas with the largestpotential risk
■ -> existing houses and infrastructures
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Norwegian Water Resources and Energy Directorate
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Flood mapping methods –steps
Flood estimation
Hydraulicmodelling
1D/2D
GIS Analysis
Flood hazardmap
Digital production
and reporting
Norwegian Water Resources and Energy Directorate
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Norwegian Water Resources and Energy Directorate
Hydraulic modelling
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• Site visits• Cross sections
Field work
• Watermarks• Boundary conditions
Calibration • 1D modelling, Hec-Ras +mike11
• 2D modelling Mike 21 +Hydro AS 2D
• Calibration
Hydraulicmodelling
Norwegian Water Resources and Energy Directorate
Hydraulic modelling
■ Site visit/cross sections■ Alb (green Laser)■ Urban area■ Water marks (calibr)■ Boundary conditions■ Modelling ->
HEC-RAS + Mike11Mike21 + Hydro AS (2D)
■ Calibration10
Norwegian Water Resources and Energy Directorate
Hydraulic simulations
■ Discharges from flood estimation■ Model
■ Results in water levels
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0 500 1000 1500 2000 2500350
355
360
365
370
375
380
162.
79
233.
1315
P3
267.
2207
P4
305.
119
P5.
5 B
RU
386.
4169
P7
425.
735
P7.
5 O
bser
vert
2011
445.
3940
P8
482.
5500
P9
536.
4312
P10
581.
5272
P11
608.
1265
633.
2941
670.
6488
696.
0299
P19
715.
8412
P20
770.
6352
P22
819.
1430
P23
887.
8465
P24
1018
.018
P26
1066
.067
P27
1104
.452
P28
1266
.185
P29
1306
.608
P30
1332
.158
P31
1372
.221
P32
1470
.868
P33
1801
.223
P34
1978
.511
P35
2191
.564
P36
2298
.549
P37
2451
.013
P38
2562
.780
P39
2690
.873
P40
2915
.937
P41
Green = Q500Red = Q200Blue = Q20
Norwegian Water Resources and Energy Directorate
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Norwegian Water Resources and Energy Directorate
GIS Analyse 1DDigital terrain model Flooded areas
Norwegian Water Resources and Energy Directorate
GIS analyse 2D
14DTMIrregular mesh
Thiessenpolygons
Norwegian Water Resources and Energy Directorate
What new in GIS analyse 2D
■ Change detectionbased on digital elevation modell ofdifferences (DoD)
■ Sediment mapping■ Differentiate
Manning’s coefficient■ Habitat modelling
15Hydrographic LiDAR
Norwegian Water Resources and Energy Directorate
What new in GIS analyse 2D
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Norwegian Water Resources and Energy Directorate
Flooded Area
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Norwegian Water Resources and Energy Directorate
Resultat frå flaumanalysen i Årdal 200-årsflaum med klima
Norwegian Water Resources and Energy Directorate
Knowledge - tools
■ Land Use Planning-> Avoid development in flood
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Norwegian Water Resources and Energy Directorate
■ Emergency-> Mitigate impacts
Civil protection
■ Protection plan-> Flood embankment
Measures in buildings
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Norwegian Water Resources and Energy Directorate
Experiences• Local involvement is important• Most of the communities are willing to use the results• Guidance and control from the government is
necessary
Norwegian Water Resources and Energy Directorate
Employees
■ Section for Hazard Mapping – 2■ Regional Office in Tønsberg – 2■ Regional Office in Førde – 1■ Regional Office in Trondheim – 2■ Regional Office in Hamar – 1■ Section for Water Balance – 2■ Section for Geoinformation – 3
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Norwegian Water Resources and Energy Directorate
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Flood maps in PDF formathttp://www.nve.no/flomsonekart
WebGIShttp://atlas.nve.no/ge/Viewer.aspx?Site=NVEAtlas
1D vs 2D- Pros and Conshttp://www.tuflow.com/Download/Presentations/Syme.Pros%20and%20Cons%20of%201D%20and%202
D%20Modelling.FMA,%20San%20Diego,%202011.pdf
Thanks for your attention!