Title: Bangladesh Flood Risk Update Flood Risk Rising
1Bangladesh Flood Risk UpdateFlood Risk Rising
- World Food Programme (WFP)
- Disaster Risk Reduction (DRR)
- 29th August 2008
2Overview
- 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
3Regional/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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5Up-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
6Approach/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)
7Bhutan
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
8Major 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
9Where in Nepal and India?Proximity to Bangladesh?
Origin of Kosi Flood
Kathmandu
Nepal
W. Bengal
10Causes 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
10
11Proximity to Bangladesh? Zoomed View
Nepal
Nepal
W. Bengal
Bihar
W. Bengal
Rangpur
Bihar
Bihar
W. Bengal
Bangladesh
Nawabganj
Rajshahi
12FFWC 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
13Graphs of Water Levels (Hydrographs) 2 FFWC
Stations Padma River Nawabaganj
DistrictTrends Flat/Steady
Trends at 3 Normal (Green) Stations also
flat/steady
14What 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
15Up-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
16Rainfall Forecast Bihar and SurroundingsTotal
Rain Morning of 29th Aug. thru Morning of 1st
Sept.
Rain Forecast Very Light to Light
Bihar and Surroundings
mms.
17What 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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19Up-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
20Rainfall Forecast Assam and SurroundingsTotal
Rain Morning of 29th Aug. thru Morning of 1st
Sept.
Rain Forecast Light to Moderate
Assam and Surroundings
mms.
21What 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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23Up-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
24Rainfall Forecast Meghalaya-Assam and
SurroundingsTotal Rain Morning of 29th Aug.
thru Morning of 1st Sept.
Rain Forecast Light to Moderate
Meghalya
Assam
mms.
25Bangladesh 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
26Conclusions/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