The Flood in Istanbul (09.09.09)

Istanbul is the largest city in Turkey and is the only metropolis in the world that is situated on two continents

1. Why Reason or What triggered the flood event ?

• natural drainage channels had been damaged and unplanned developments blocked the rain water from dissipating into the sea (Marmara Sea). That is, many buildings were made to closed gully and to make narrow the river bed in recent years. Therefore Istanbul is known to suffer from poor drainage (See pictures).

• The insufficiency of water absorbing green areas and forests in the heart of the city is another factor that blocks water in the midst of concrete.

• Heavy rain

satellite image (years of 2009) satellite image (years of 1982)

Urbanization on channel side (Halkali – TIR garage)

Rubble area

Changing the channel structure and direction (Halkali intersection)

satellite image (years of 2009) satellite image (years of 1982)

Zonal Map of Istanbul

The flood event occured in Shantyhouse (illegal settlement) zone and in areas of forests has been destroyed

Historical zoneShantyhouse zonePlanned residential zoneCentral work zoneIndustrial zoneForest zone

Flood event occured in

Marmara Sea

Black Sea

Soil Erosion in Istanbul

Event occurred and the area above flood basin (unforested zone) is exposed to severe erosion

2. How much was raining that day in Istanbul?

• Istanbul received 205 kilograms of rainwater per square meter

• The amount of rain that has fallen in two days roughly equals what

normally falls in six months in the Turkish province

• the river beds were elevated 3 meters in 10 minutes

(Source : www.ibb.gov.tr – Istanbul Metropolitan Municipality)

Precipitation

Amount of rainfall during the flood event, about 5.5 times greater

(205 kilograms of rainwater per square meter) than average in

the month of September

Long-Term Monthly Precipitation Graph (Istanbul)

83.5

62 63.4

48.5

36.227.3

36.330.2

36.1

80.788

105.1

0

20

40

60

80

100

120

Months

Pre

cip

itat

ion

am

ou

nt

(kg

/m2)

In Some Meteorological (Weather) Stations, Close to Flood Zone, for Daily Rainfall

0 0

11.3

133.

7

16.4

0.3 1.8

0 0.5

10.5

120.

9

25.3

0 1.3

0 0

3.4

97.6

12.5

0 0.6

0 2.2

2.2

82.8

9.6

0 0.3

0 1

75

67.6

5.9

0 0.5

0 0

6.4

63.6

42.8

0 2.6

0 0

3.8

56.6

24

0.2 2.4

0

20

40

60

80

100

120

140

160

06.09.2009 07.09.2009 08.09.2009 09.09.2009 10.09.2009 11.09.2009 12.09.2009

Days

Pre

cip

ita

tio

n (

kg

/m2

) Silivri

Hadimkoy

Sariyer - Kirecburnu

Kumkoy

Terkoz

Merkez-Florya

Bakirkoy-Ataturk Airport

The flood day

3. Damage from the flood

• killed 31 people,• around Istanbul after the worst rainfall in 80 affected schools and

hospitals, • affected thousands of residential and office buildings, • the costs of flood damage could reach $70m to $80m

(Source : www.globalreinsurance.com)

4. Some pictures from media

Local residents and rescue workers gather near partially submerged and flood-damaged vehicles in Istanbul on Wednesday, Sept. 9.

An aerial view shows flood-damaged vehicles on Sept. 9 in Istanbul.

An aerial view of the trucks swept by flash floods in Istanbul (Halkali intersection)

September 9, 2009

Flooded main highway that links the city center to Ataturk airport is seen in Ikitelli, Istanbul, Turkey, Wednesday, Sept. 9, 2009.

Passengers of a bus stranded on a flooded highway wait to be rescued in the Ikitelli

district of Istanbul on Sept. 9.

Rescuers evacuate people trapped in a bus in Ikitelli, Istanbul, Turkey, Wednesday, Sept. 9, 2009

A man waiting to be rescued stands on partially submerged vehicles after heavy rains in Istanbul on Sept 9.

A woman stranded on her balcony awaits rescuers following heavy rain and flooding in the Halkali - Istanbul on Tuesday, Sept. 9.

People survey washed-out roadways following flash floods in Halkali, on Sept. 9.

Residents begin the tedious task of cleaning debris from their properties on Sept. 9 after flash floods swept through Halkali

Thank you for your attentions