Strategies for adaptation of urban drainage systems to climate change

by

Ole Mark, DHI

Urban Stormwater Management Urban Stormwater Management in Developing Countriesin Developing Countries

Jonathan ParkinsonJonathan Parkinson

Ole MarkOle Mark

IWA Publishing

2005

www.iwapublishing.com

ISBN: 1-843390-57-4

Relationships between areas of development, urban catchments and river basin

Conceptual framework and operational structure for IWRM

Main components of integrated urban water management

Stormwater drainage - an integral component of urban environmental management

The priorities of a city ?

1.Drinking water

2.Sanitation / sewers

3.Wastewater treatment & reduction of flooding

4.Reduction of pollution in recipients

5.Recreative values of water

Dubai

Excessive amounts of litter in a drainage channel in Dhaka

Source: Urban Stormwater Management in Developing Countries, 2005 Photo: Birgitte Helwigh

Blocked inlet to the stormwater drainage system in Dhaka

While waiting for the next flood in your city…

Karachi, Pakistan – 19th August 2006Power supply,telecommunication,moblie systems disrupted

Rain related death toll: 26Rain: 50-60 mm…..

While waiting for the next flood in your city…

Urban poor living on the banks of an urban river in Jakarta, Indonesia

Causes and types of urban flooding

Initial elevation grid

Grid with streets

Final grid with streets and buildings

Lowering by 20 cm places where there are

streets

Raising by 5 m places where there are buildings

Today, the model is a copy of the city….

Modeling of flooding in cities

What is flooded ?

What does flooding cost ?

Direct Damages

Traffic Planning

Flood damage reduction

1. Land use planning

2. Reduction of the flood extent

3. Reduction of the interaction with the flood

4. Control of the surface runoff and subsequently flooded areas

5. Emergency plans and actions

6. Flood warning and information systems

Wh

ile w

ait

ing

for

the n

ext

flood

in

you

r cit

y…

.Do you believe in climate

changes ?

• Will a 10 year rain become a 2-3 year rain ??

30 years => 5 years ?

• Can/will we ”build” fast enough ??

• What do we do - When we get flooded ?

Clim

ate

ch

an

ge

This should be avoided…

This was the control of a pumping station

Flooding computed for a new “climate” 10 year rain

The football field in Greve

Flooding computed for a new “climate” 10 year rain

The football field as flood strorage…

Beijing – 2004

Clim

ate

ch

an

ge

Informed decissions!!!

How should we handle extreme rain fall and

climate changes in the urban areas?

Clim

ate

ch

an

ges

So while you are waiting for the climate changes and the next flood in your city – spend some time to think about:

1. What will be flooded ?

2. What will it cost ?

3.How can damages be reduced ?

4.Can you learn something from other places ?

Clim

ate

ch

an

ges

Summary

• Analyses of urban flooding

• Climate & Risk/Hazard analyses

• Timely management (climate, planning, cost-

benefit, etc)

Today

In the future

Managment of climate changes