Bangladesh Flood Risk Update Flood Risk Rising

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Bangladesh Flood Risk UpdateFlood Risk Rising

• World Food Programme (WFP)
• Disaster Risk Reduction (DRR)
• 29th August 2008

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Overview

• Factors contributing to higher risk
• Regional Geography Up-Stream Perspective
• Situation in Bangladesh
• Situation Upstream
• Risk of significant flooding is now higher
  situation has changed
• Higher risk areas in Bangladesh
• Preparedness Actions Needed

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Regional/Upstream Perspective Critical

• In an average year, during May-October, about 1
  trillion cubic meters of water flows through
  Bangladesh
• 17 of that water comes from rainfall inside
  Bangladesh
• 83 is In-flow from rain and rivers outside
  the country
• 78 of the in-flow comes via the three main
  rivers Bhramaputra-Jamuna, Ganges/Padma, and the
  Meghna
• Regional perspective (i.e. Upstream monitoring)
  matters - - A lot !!
• Source Banglapedia

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Up-Stream Drainage Basins
Sikkim
Bhutan
Assam
Nepal
2
Tista
Assam
Brahmaputra
Assam
1
Bihar
Meghalaya
3
Ganges-Padma
Meghna
M e g h n a
Up-Stream Basins and Rivers
1. Bihar/W. Bengal Ganges-Padma
3. Meghalaya/Assam Meghna
2. Assam Brahmaputra-Jamuna Sikkim Tista
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Approach/Methodology

• For Each Basin (Map-Zone) we look at
• Known/Confirmed Flooding Events (if any)
• Causes Updates
• River Levels current
• River Level forecasts and trends
• Rainfall forecasts and trends
• Flood Risk near term (approx. next 3-5 days)

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Bhutan
Sikkim
Assam
Nepal
Assam
1
Bihar
Meghalaya
Assam
Ganges-Padma
M e g h n a
Up-Stream Basins and Rivers
1. Bihar/W. Bengal Ganges-Padma
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Major Floods in Bihar IndiaWhat Happened?

• Nepals Kosi River Dam breaks 18th August
  embankments downstream breached
• Major flooding occurs in Nepal, and downstream in
  Bihar
• Bihar 2-3 Million people affected,
• Nepal more than 100,000 displaced

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Where in Nepal and India?Proximity to Bangladesh?
Origin of Kosi Flood
Kathmandu
Nepal
W. Bengal
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Causes of Kosi Flood? Heavy Rainfall?

• Notes
• Kosi Dam breaks 18th August
• Rainfall was 2 to 4 times (200-400)
• higher than Normal
• for period 11th-20th August.
• Heavy Rains not wide-spread but location
  specific at Nepal-India Kosi area border.
• 4. Not entirely clear whether rain highlighted
  in map played a causal role.
• 5. Rainfall Source
• USAID FEWSNET RFE-2
• 6. Normal based on a 7 yr. Average.

Rainfall 11th-20 August 2008 Percent of Normal
Nepal
Bhutan
2008 vs. Avg. ( Change )
400
Bihar
West Bengal
200
125
Bangladesh
West Bengal
110
90
India
75
50
25
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Proximity to Bangladesh? Zoomed View
Nepal
Nepal
W. Bengal
Bihar
W. Bengal
Rangpur
Bihar
Bihar
W. Bengal
Bangladesh
Nawabganj
Rajshahi
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FFWC Padma Stations relatively close to
W.Bengal/Bihar
What is happening w/ river levels in these areas?
Source FFWC 29 Aug. 2008
Source Google Maps, Maplandia
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Graphs of Water Levels (Hydrographs) 2 FFWC
Stations Padma River Nawabaganj
DistrictTrends Flat/Steady
Trends at 3 Normal (Green) Stations also
flat/steady
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What is happening w/ river levels
Up-StreamBihar and Surroundings ?

• 21 Stations at or above Warning Level.
• 13 of 21 at Danger Level or Higher
• 8 of 21 at Warning Level or Higher and below
  Danger Level
• Source India Central Water Commission
• River level measurements taken morning of 29th
  August
• Information above pertains to Bihar, W. Bengal,
  Jharkhand
• Data changes Frequently latest Updates available
  at
• http//www.india-water.com/ffs/index.htm

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Up-Stream River Level TrendsBihar and
Surroundings
Warning Level (or Higher)
Number of Stations
Danger Level (or Higher)
26 Aug
27 Aug
28 Aug
29 Aug
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Rainfall Forecast Bihar and SurroundingsTotal
Rain Morning of 29th Aug. thru Morning of 1st
Sept.
Rain Forecast Very Light to Light
Bihar and Surroundings
mms.
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What is happening w/ river levels
Up-StreamAssam and Surroundings ?

• 8 Stations at or above Warning Level.
• 3 of 8 at Danger Level or Higher
• 5 of 8 at Warning Level or Higher and below
  Danger Level
• Source India Central Water Commission
• River level measurements taken morning of 29th
  August
• Information above pertains to Bihar, W. Bengal,
  Jharkhand
• Data changes Frequently latest Updates available
  at
• http//www.india-water.com/ffs/index.htm

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Up-Stream River Level TrendsAssam and
Surroundings
Warning Level (or Higher)
Number of Stations
Danger Level (or Higher)
26 Aug
27 Aug
28 Aug
29 Aug
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Rainfall Forecast Assam and SurroundingsTotal
Rain Morning of 29th Aug. thru Morning of 1st
Sept.
Rain Forecast Light to Moderate
Assam and Surroundings
mms.
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What is happening w/ river levels
Up-StreamMeghalaya-Assam and Surroundings ?

• 8 Stations at or above Warning Level.
• None at Danger Level or Higher
• One at Warning Level or Higher and below Danger
  Level
• Source India Central Water Commission
• River level measurements taken morning of 29th
  August
• Information above pertains to Bihar, W. Bengal,
  Jharkhand
• Data changes Frequently latest Updates available
  at
• http//www.india-water.com/ffs/index.htm

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Up-Stream River Level TrendsMeghalaya-Assam and
Surroundings
Warning Level (or Higher)
Number of Stations
Danger Level (or Higher)
27 Aug
28 Aug
29 Aug
26 Aug
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Rainfall Forecast Meghalaya-Assam and
SurroundingsTotal Rain Morning of 29th Aug.
thru Morning of 1st Sept.
Rain Forecast Light to Moderate
Meghalya
Assam
mms.
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Bangladesh South-East Chittagong, Coxs Bazar
and Surroundings

• In addition to the analysis presented in previous
  slides Very Heavy Rain has fallen in SE
  Bangladesh and Flash Flooding has occurred
• Some assistance has been provided GoB and UNICEF

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Conclusions/Recommendations

• Flood Risk in Bangladesh has become higher in
  recent days mostly because of heavy rain and
  high river levels Up-Stream and also because of
  heavy rain in some areas of Bangladesh
• Situation has deteriorated and may continue to
  deteriorate in coming days
• Close Monitoring needed
• Stepping up preparedness for potential rapid
  response warranted