Bangladesh Flood Risk Update Flood Risk Rising by bim75537

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									Bangladesh Flood Risk Update
      Flood Risk Rising



     World Food Programme (WFP)
     Disaster Risk Reduction (DRR)
           29th August 2008
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
     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
       Up-Stream Drainage Basins

                       Sikkim
                                Bhutan
          Nepal                                      Assam


                                2            Assam
                                                     Assam

        Bihar      1                Meghalaya
                                         3




                Up-Stream Basins and Rivers
1. Bihar/W. Bengal: Ganges-Padma                3. Meghalaya/Assam: Meghna
2. Assam: Brahmaputra-Jamuna + Sikkim: Tista
         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)
              Sikkim   Bhutan
 Nepal                                       Assam



                       Assam

Bihar     1
                         Meghalaya

                                     Assam




        Up-Stream Basins and Rivers
  1. Bihar/W. Bengal: Ganges-Padma
           Major Floods in Bihar India
               What Happened?
   Nepal’s 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
    Where in Nepal and India?
    Proximity to Bangladesh?

                 Origin of Kosi Flood
Kathmandu



   Nepal
                W. Bengal
                  Causes of Kosi Flood?
                     Heavy Rainfall?
                                                    Notes:
                         Rainfall: 11th-20 August   1.   Kosi Dam breaks
                         2008 Percent of Normal          18th August
                                                    2.   Rainfall was 2 to 4
                Nepal                 Bhutan             times (200-400%)
2008 vs. Avg.                                            higher than Normal
                                                         for period 11th-20th
( % Change )                                             August.
     400%                                           3.   Heavy Rains not
                 Bihar    West
                         Bengal                          wide-spread; but
     200%                                                location specific at
                                                         Nepal-India Kosi
     125%                                                area border.
                           West    Bangladesh       4.   Not entirely clear
     110%                 Bengal
                                                         whether rain
                                                         highlighted in map
     90%                                                 played a “causal”
                India                                    role.
     75%
                                                    5. Rainfall Source:
                                                         USAID FEWSNET RFE-2
     50%
                                                    6. “Normal” based on a 7
                                                         yr. Average.
     25%

     10%
 Proximity to Bangladesh?                         Zoomed View

Nepal             Nepal


        Bihar




                          W. Bengal
                                                       Rangpur

        Bihar
                Bihar
                               W. Bengal


                                                  Bangladesh
                                      Nawabganj


                                          Rajshahi
                            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
Graphs of Water Levels (Hydrographs) 2 FFWC Stations;
           Padma River Nawabaganj District
                 Trends; Flat/Steady


                                       Trends at 3 Normal (Green)
                                       Stations also flat/steady
  What is happening w/
 river levels Up-Stream:      21 Stations at or
Bihar and Surroundings ?       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
                 Up-Stream River Level Trends
                    Bihar and Surroundings


                                                  Warning
                                                  Level
                                                  (or Higher)
 Number
of Stations                                       Danger
                                                  Level
                                                  (or Higher)




              26 Aug   27 Aug   28 Aug   29 Aug
            Rainfall Forecast: Bihar and Surroundings
    Total Rain: Morning of 29th Aug. thru Morning of 1st Sept.




Rain Forecast:
Very Light to Light
                       Bihar and
                      Surroundings




                                                         mms.
What is happening w/ river
    levels Up-Stream:           8 Stations at or
Assam and Surroundings ?         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
  Up-Stream Drainage Basins

            Sikkim
                     Bhutan
    Nepal                                   Assam


                     2          Assam


                         Meghalaya
                                        Assam




      Up-Stream Basins and Rivers
2. Assam: Brahmaputra-Jamuna + Sikkim: Tista
                 Up-Stream River Level Trends
                   Assam and Surroundings


                                                  Warning
                                                  Level
                                                  (or Higher)
 Number
of Stations                                       Danger
                                                  Level
                                                  (or Higher)




              26 Aug   27 Aug   28 Aug   29 Aug
           Rainfall Forecast: Assam and Surroundings
    Total Rain: Morning of 29th Aug. thru Morning of 1st Sept.




  Rain Forecast:
                                         Assam and
Light to Moderate                       Surroundings




                                                         mms.
What is happening w/ river
   levels Up-Stream:
 Meghalaya-Assam and            8 Stations at or
     Surroundings ?              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
Up-Stream Drainage Basins

               Bhutan
 Nepal




                 Meghalaya 3




   Up-Stream Basins and Rivers
3. Meghalaya/Assam: Meghna
                Up-Stream River Level Trends
              Meghalaya-Assam and Surroundings


                                                  Warning
                                                  Level
                                                  (or Higher)
 Number
of Stations                                       Danger
                                                  Level
                                                  (or Higher)




              26 Aug   27 Aug   28 Aug   29 Aug
 Rainfall Forecast: Meghalaya-Assam and Surroundings
Total Rain: Morning of 29th Aug. thru Morning of 1st Sept.




                          Meghalya               Rain Forecast:
                                               Light to Moderate




                                        mms.
         Bangladesh South-East
Chittagong, Cox’s 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
    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

								
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