Communication and Dissemination of Community based Flood Information System in Bangladesh Ahmadul Hassan
Objective of CFIS Dissemination of Flood Level information to the community with a lead time before the flood occurs
Project Location SIRAJGANJ SADAR BHUAPUR Sirajganj GHATAIL # Y Sirajganj KAMARKHANDA KALIHATI BELKUCHI 55 km 57 km TANGAIL SADAR BASAIL Sirajganj CHAUHALI Jamuna River r SHAHJADPUR e Dhaleswari River v i DELDUAR R a MIRZAPUR n Dhaleswari River u NAGARPUR m a J Dhaleswari River SATURIA DAULATPUR BERA 26 km Dhaleswari River Old Dhaleswari River GHIOR Toraghat Taraghat # Y K a l i g a n g a R i v e r Aricha Teota Y # MANIKGANJ SAD
Information and Dissemination • COMMUNITY – Information mechanism directly to the community level – Flag and Billboard Network – Improves lead time – Requires little or no literacy – Field tested: • Calibration • Local Operators • Capacity Building
Need: Format of Information Dissemination • COMMUNITY – Billboard Network: • Predicted flood extent on high-resolution image of community • Predicted trend and relative water level rise – Flag Network: • Predicted water level rise when close to or above danger level
Information Network Portal
Conceptual diagram of CFIS Input: - GIS Riv Networks Forecasted WL (FFWC) at u/s and d/s - FFWC WLs Observed WATSURF WLs GIS maps Output: - WL change after 48 hr in terms of ‘ Bighat’ SMS flag Msg - inundation maps Flood map Water level measurement Community using flood message
Topography: Digital Elevation Model (DEM)
Development of CFIS tool: WL Measurement 4119 4119 • In 2003 – 17 gauges 4106 4106 • In 2004 – 18 gauges 3109 3109 4118 4118 3108 3108 3107 3107 3105 3105 4104 4104 4112 4112 4110 4110 4113 4113 Key water level gauges 4116 4116 3111 3111 4115 4115 Gauge 49: Sirajganj Gauge 50.5: Aricha 3117 3117 4101 4101 4102 4102
Tora Sirajganj Aricha Model schematic
Development of Relationships The lag-time for Sirajganj to reach each individual gauge is estimated by studying the hydrographs before the equation is derived. 72 hours
Development of Relationships The lag-time for Sirajganj to reach each individual gauge is estimated by studying the hydrographs before the equation is derived. Sirajganj, Aricha, Gauge-3109 16 14 WL (m+pwd 12 48 hours 10 8 Gauge-3109 Sirajganj Aricha 6 4 1-Jul 11-Jul 21-Jul 31-Jul 10-Aug 20-Aug 30-Aug 9-Sep 19-Sep
Development of Relationships WL at any gauge in the study area is function of water level at Sirajganj (considering the lag time) and Aricha C1*SirajWL (-24h) +C2*SirajWL (-48h) WL (at gauge) = + C3*SirajWL (-72h) +C4*ArichaWL (today) +B 15 Equations have been developed for each Gauge
The Model Sirajganj WL Aricha WL (FFWC) (FFWC) Equations Estimated WL Spatial Map DEM Engine Msg outputs Msg outputs Msg outputs
Community flood risk level Below Normal No Color Flood Normal Flood Green Moderate Yellow Flood Severe Flood Red Flood levels are being marked on concrete pillar
Community Flood Message Water level Flag Description change Today flood status Top flag: No flag – the water level at gauge is at No flag, below the Normal Flood level Green – the water level at gauge is within Green, the Normal Flood range Yellow, Red Yellow – the water level at gauge is within the Moderate Flood range Red – the water level at gauge is above the Moderate Flood range Water level after Except the No Flag - WL change < 1 bghat (22 cm) 48 hr topmost flag White Flag – decrease of WL Blue Flag – increase of WL
Model Execution
Local Level Product List Six types of flood forecasting products from tool WATSURF for dissemination through its network 1. District level gauge water levels 2. Upazila gauge station water level map 3. Upazila gauge station water level table 4. Mouza water level forecast table 5. Community water level change forecast flag signal
Local Level Product – 1 (District) This product represent flood situation at district level as predicted by FFWC at and around the Tangail and Manikganj
Local Level Product – 2 (Upazila) Water level changes in gauges at Upazila level in the form of symbols representing rise/fall in local units. The maps are faxed to the DC and UNO offices
Local Level Product – 3 (Upazila) The water level changes in next 48 hrs in Tabular form are faxed to Upazila HQ
Local Level Product – 4 (Union) Flood message for all Mouzas within the targeted Union through SMS, and subsequently displayed on bulletin board
Local Level Product – 5 (Mauza/Community) Flood map Flood message for flag site/Mouza through SMS for hoisting warning flags.
Other Products • Flag maps using WATSURF • Flood Extent using RADARSAT Image • Monsoon Land Use mapping
Other WATSURF Outputs
Other outputs
Flood Monitoring –Local Open Water flooding - Extent Satellite images used RADARSAT Fine Beam RADARSAT Fine Beam images were used to images were used to identify open water extent identify open water extent 2 August 2004
09 July 2004
02 August 2004
26 August 2004
19 September 2004
Flood Monitoring – Local Presentation Layout Aman Map RADARSAT RADARSAT Fine Beam Fine Beam Bhara images were images were used for Aman used for Aman Sahabatp rice mapping rice mapping ur Gayhat a Mokna Salimabad Nagarpur Mamudnagar Dhubaria Bhadra Duptiar Jianpur Kalia Chak Mirpur Dhamsar Khalsi
Result Analysis
Comparison: Prediction vs Observed WLs
Comparison: Prediction vs Observed WLs
Comparison: Prediction vs Observed WLs
Comparison: Prediction vs Observed WLs
Comparison: Prediction vs Observed WLs
Comparison: Prediction vs Observed WLs
Comparison: Prediction vs Observed WLs
Comparison: Prediction vs Observed WLs
Model Result vs Observed WL for Flag 80 70 86% 83% 82% 79% 78% 78% 75% 75% 76% 75% 75% 75% 74% 74% 71% 60 Number of days 50 40 30 Total Data (days) 20 Days Comply with WATSURF 10 0 3105 3107 3108 3109 3111 3117 4102 4104 4106 4110 4113 4115 4118 4119 4121 Gauges
Model Result vs Observed WL change Gauge Total Blue White No Change Name Data Pred Obs Comply % Pred Obs Comply %Pred Obs Comply % Tebaria 61 14 14 100% 19 19 100% 28 15 54% Boro Boinya 57 12 12 100% 16 15 94% 29 15 52% Sunsi 61 9 9 100% 17 15 88% 35 16 46% Kakna 65 14 14 100% 20 20 100% 31 7 23% G3109: Tebaria Boro Boinya 28 30 35 29 30 25 19 19 25 20 15 20 14 14 16 15 15 15 15 12 12 10 10 5 5 0 0 Blue White No Change Blue White No Change Sunsi Kakna 40 35 35 30 30 25 25 20 20 15 15 10 10 5 5 0 0 Blue White No Change Blue White No Change
Post Flood Social Assessment
Technical assessment (an example)
Threshold Level at 3111
RMS error of predicted change in stage(m)
Difficulties Odds experienced • Zero value error during gauge connection - this created a constant vertical offset in hydrograph • Introduction of error during gauge shifting which caused erroneous WLs • Gauge management: in few cases the gauges were found not vertical due to thrust of floating things, and those were not fixed in time in absence of care and funds • Error in making SMS message to send WLs • SMS communication disrupted due to Network failure, recharging problem and disconnected mobile due to irregularities in bill payments
CFIS at a glance! • Technological – Easy to implement – Simple approach – Less higher skill required • Institutional – Society and GoB involved • Financial – Implementation cost – Operation & Maintenance cost
Thank You
Recommend
More recommend
