civil engineering

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


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


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)


)0(

10000/1

)(DP

dPPPDEAD

)0(

10000/1

)(DP

dPPPCEANC

•Graduality


GResis.=0 GResil.=0.91 GComb.=0.7

•Recovery Rate/Capacity


•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


•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



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


JWRC April 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


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 39400

00

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


Drainage System

(North and East)Drainage System


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

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







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


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

Engineering

civil engineering