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Sustainable Flood Risk Management
Babak Bozorgy
HIPS Lunchtime Seminar, 23 Mar. 2008
Buzz words
• Sustainability
• Integrated Water Resources Management (IWRM)
Sustainability
• Do what is needed now, but without compromising the needs of future generations
• sustainability = trade-offo now versus futureo economy versus environment
IWRM
• Integration of:o surface water and groundwatero quantity and qualityo ecological aspectso other fields: environmental planning, spatial
planning, etc
• from sectoral approach to holistic approach• process orientation + economics + institutions
Dublin principles - 1992
• Fresh water is a finite and vulnerable resource, essential to sustain life, development and environment
• Water development and management should be based on a participatory approach, involving users, planners and policy makers at all levels
• Women play a central part in the provision, management and safeguarding of water
• Water has an economic value in all its competing uses and should be recognized as an economic good
Definition of IWRM
Global Water Partnership (GWP), 2000:IWRM is a process which promotes the co-ordinated development and management of water, land and related resources, in order to maximise the resultant economic and social welfare in an equitable manner without compromising the sustainability of vital ecosystems
See: Tec 4 of GWP
natural system
impacts
demandsnatural system socio-economicsystem
infrastructure
impacts
demands
laws,regulations,
management
natural system
institutionalsystem
socio-economicsystem
infrastructure
impacts
demands
laws,regulations,
management
natural system
institutionalsystem
socio-economicsystem
integratedwater resourcesmanagement
Identify issues
Evaluation
Implementation
Action planning
Select alternative
Design and assess alternative
Analyse problems
Content
Awareness raising
Mobilising actors
Dialogue
Link problems-solutions
Negotiate contributions
Fix commitment
Express concerns
Process
IWRM
• IWRM is a learning process (steps, interaction)
• IWRM = balancing of interests (functions)
• To be applied at river basin level• Implementation is culture and
situation dependent
Learn from others, don’t copy !
The challenge of IWRM
To strike a balance between the use of the resources as a basis for livelihood and the protection and conservation of the resource to sustain its functions and characteristics
Flood
•Floods are the most common and destructive events among natural disasters
•Flood events and their damages have been increased in the recent decades
Flood Management
•So, traditional approaches of flood management have not been able to control the damages of floods and adoption of new approaches is essential. The need for new approaches of Sustainable Development, Risk Management and Resilience is emphasised in:
Flood Management
•Earth Summit, UN Div. for S.D., Agenda 21, Rio, 1992
• Intl. Strategy for Disaster Reduction, UN, 2000
• World Summit on S.D. (WSSD), Johannesburg, 2003
•Intl. Decade for Action, Water for Life 2005-2015, UN G.A.
Traditional and new approaches to flood management
Risk = event probability * consequences
Flood Management
Traditional and new approaches to flood management
Risk = event probability * consequences
Traditional strategies = Resistant strategies
= Flood control to reduce event probability with resistant measures such as dikes
increased dikes height = increased confidence = increased economic development = increased risk
Flood Management
Risk = event probability * consequences
New strategies = Risk management strategies = Resilient strategies
Introduced as one of the principles of Sustainable Development
Flood Management
Resilience = Ability of a system to withstand disturbances by recovery
Resistance = Ability of a system to withstand disturbances without any reaction
Flood Management
Resilience in natural disasters is one of the elements of Sustainable Development
Flood Management
IFM is a process that promotes an integrated, rather than fragmented, approach to flood management. It integrates land and water resources development in a river basin, within the context of IWRM, and aims to maximize the net benefit from floodplains and to minimize loss to life from flooding
Ref.: Associated Programme on Flood Management (APFM), GWP
Integrated Flood Management (IFM)
•More Room for Rivers or Learning to Live With Floods
•Landuse Planning
•Green Rivers (Bypass Channels)
•Compartments (Detention Ponds)
•Flood Forecasting and Flood Warning
•Evacuation Plans
•Flood Insurance
Resilient Strategies in Flood Management
Quantifying resilience by indicators
•Amplitude
• Expected Annual Damages (EAD)
• Expected Annual Number of Casualties (EANC)
Resilient Strategies in Flood Management
∫=
=)0(
10000/1
)(DP
dPPPDEAD
∫=
=)0(
10000/1
)(DP
dPPPCEANC
•Graduality
Resilient Strategies in Flood Management
GResis.=0 GResil.=0.91 GComb.=0.7
•Recovery Rate/Capacity
Resilient Strategies in Flood Management
•Ranking the different flood risk management strategies and choosing the best/most resilient strategy is a Multi-Criteria Decision Making (MCDM) problem which can be addressed by Multi-Criteria Evaluation (MCE) techniques. This is also called Decision Support System (DSS)
Multi-Criteria Decision Making
Gorgan River Basin, North-West Iran
Case Study
Case Study
Reach 2 – Urban Area
Reach 1 – Rural Area
Flood Management Strategies:
•Strategy #1: Natural Conditions
•Strategy #2: Golestan Dam
•Strategy #3: Dikes along the reaches
•Strategy #4: Green Rivers
•Strategy #5: Flood Warning System
•Strategy #6: Flood Insurance
•Strategy #6: Flood Warning System & Flood Insurance
Case Study
Flood Inundation Modelling (Flood Mapping)
•For all the strategies with 2, 5, 10, 25, 50, 100, 200, 500, 1000, 2000, 5000 and 1000 years return periods with MIKE FLOOD (Dynamic couple of MIKE 11 and MIKE 21)
Case Study
Flood mapping in Strategy #1, 1000 years flood
Case Study
Flood Damage (EAD) Estimation and Mapping
Case Study
Flood damage mapping in Strategy #1, 1000 years flood
Casualties (EANC) Estimation and Mapping
Case Study
Casualties mapping in Strategy #1, 1000 years flood
Casualties (EANC) Estimation and Mapping
Case Study
Casualties mapping in Strategy #1, 1000 years flood
Ranking of the strategies by MCDM
Case Study
Evaluation Matrix
Decision Matrix
Case Study
2nd part
Thank you for your attention
“No loss by flood and lightening, no destruction of cities and temples by the hostile forces of nature, has deprived man of so many noble lives and impulses as those which his intolerance has destroyed”
Helen Keller
Tehran Flood Mitigation Studies
Tehran Flood Mitigation Studies
•15th largest city in the world in terms of population (Ref.: Wikipedia) (8-12 mill.)
•700 km2
•>800m difference in altitude in urban area
•>2500m difference in altitude in the catchment area
•Very steep slope in North-South direction
•Very mild slope in East-West direction
Tehran Flood Mitigation Studies
Tehran Flood Mitigation Studies
Niayesh Highway – Sepah Complex (7th March 2005)JWRC April 2005
Farahzad St. (7th March 2005)
JWRC April 2005
Farahzad St. (7th March 2005)
JWRC April 2005
Sazman-e-Ab St. (7th March 2005)
JWRC April 2005
Farahzad Water Way (7th March 2005)JWRC April 2005
Azari T- Junction (7th March 2005)JWRC April 2005
Tappeh Neyzar Channel (7th March 2005)
JWRC April 2005
Tappeh Neyzar Channel (7th March 2005)
JWRC April 2005
West Flood Diversion Channel (7th March 2005)
Farahzad River Diversion Channel
JWRC April 2005
Niayesh Highway (7th March 2005)
JWRC April 2005
Niayesh Highway (7th March 2005)
JWRC April 2005
Niayesh Highway (7th March 2005)
JWRC April 2005
Yadegar Highway (7th March 2005)
JWRC April 2005
Yadegar Highway (7th March 2005)
JWRC April 2005
JWRC April 2005
Resalat Highway
Velenjak River
Velenjak River – Moqaddas Ardebili Cross
Velenjak River – Sediment Detention Basin
Velenjak River – Downstream of Sediment
Detention Basin
JWRC April 2005
Velenjak River – Between Moqaddas Ardebili and Chamran Highway
Velenjak River – Nil St. Velenjak River – MIrdamad Cross
Velenjak River – Entrance to the Diversion Tunnel
JWRC April 2005
Tehran Flood Mitigation Studies
4
5 2
1
22
3
21
6
9
18
7
15
8
20
16
14
13
1211
19
17
10N
EW
S
Regions of TehranFlood ways of Tehran
3 0 3 6 9 Kilometers
510000
510000
515000
515000
520000
520000
525000
525000
530000
530000
535000
535000
540000
540000
545000
545000
550000
550000
555000
555000
393
500
0 39350
00
394
000
0 3940
000
394
500
0 39450
00
395
000
0 39500
00
395
500
0 39550
00
396
000
0 39600
00
396
500
0 39650
00
Tehran Flood Mitigation Studies
Drainage System
(North and East)Drainage System
Tehran Flood Mitigation Studies
N
EW
S
526000
526000
528000
528000
530000
530000
532000
532000
534000
534000
536000
536000
538000
538000
540000
540000
542000
542000
3954
000 3954000
3956
000 3956000
3958
000 3958000
3960
000 3960000
3962
000 3962000
3964
000 3964000
3966
000 3966000
3968
000 3968000
3970
000 3970000
3972
000 3972000
City Boundary
U/S BasinsLower than 1200 m1200 - 1500 m1500 - 1800 m1800 - 2100 m2100 - 2400 m2400 - 2700 m2700 - 3000 m3000 - 3300 m3300 - 3600 mUpper than 3600 mNo Data
Basin BoundaryBuildings
4 0 4 8 12 Kilometers
Tehran Flood Mitigation Studies
4
5 2
1
22
3
21
6
9
18
7
15
8
20
16
14
13
1211
19
17
10
N
EW
S
526000
526000
528000
528000
530000
530000
532000
532000
534000
534000
536000
536000
538000
538000
540000
540000
542000
542000
395
4000
3954000
395
6000
3956000
395
8000
3958000
396
0000
3960000
396
2000
3962000
396
4000
3964000
396
6000
3966000
396
8000
3968000
397
0000
3970000
397
2000
3972000
Slope of Tehran0 - 1 %1 - 5 %5 - 10 %10 - 15 %15 - 20 %20 - 30 %30 - 4040 - 50 %Upper than 50 %No Data
Regions of Tehran
6 0 6 12 18 Kilometers
Tehran Flood Mitigation Studies
Tehran Flood Mitigation Studies
Tehran Flood Mitigation Studies
Tehran Flood Mitigation Studies
Tehran Flood Mitigation Studies
N
EW
S
Basin AreaLower than 1200 m1200 - 1500 m1500 - 1800 m1800 - 2100 m2100 - 2400 m2400 - 2700 m2700 - 3000 m3000 - 3300 m3300 - 3600 mUpper than 3600 mNo Data
Buildings100 Year Flood PlainFlloodways
2 0 2 4 6 8 Kilometers
518000
518000
520000
520000
522000
522000
524000
524000
526000
526000
528000
528000
530000
530000
532000
532000
534000
534000
394
200
0 39420
00
394
400
0 39440
00
394
600
0 39460
00
394
800
0 39480
00
395
000
0 39500
00
395
200
0 39520
00
395
400
0 39540
00
395
600
0 39560
00
395
800
0 39580
00
396
000
0 39600
00
396
200
0 39620
00
396
400
0 39640
00
396
600
0 39660
00
396
800
0 39680
00
Tehran Flood Mitigation Studies
Thank you for your attention
“No loss by flood and lightening, no destruction of cities and temples by the hostile forces of nature, has deprived man of so many noble lives and impulses as those which his intolerance has destroyed”
Helen Keller