Dynamic flood warning system: An integrated approach to disaster mitigation in Bangladesh
Profile of the Study Area
Sundarganj Thana of Gaibandha district in Bangladesh has been selected as the case study (figure 2). It is located in the northern part of the country bounded by two major rivers Brahmaputra (Jamuna) in the eastern and Teesta in the northern part of Bangladesh. Due to topographical condition the area is subjected to floods almost every year because of low gradient of the terrain. The terrain is basically alluvium flood plain and is not much stable as the river courses changes continuously. The region is characterized by shallow depressions and valleys of moribund river channels created by a long morphological history of changes in the river courses. Flash flood is caused by the river Teesta and the river flooding by the river Jamuna. Excessive precipitation, localized drainage congestions and insufficient capacity of hydraulic structures are the causes of flooding in this area.  Figure.2: Sunderganj Thana of Gaibandha district, Bangladesh Information supplies for the Development of Warning System With the increase of population, industrial growth, more and more settlements and development in flood plains, flood hazards in Bangladesh have become ever-increasing natural disasters resulting in causing the highest economic damage among all kinds of natural disasters around the world. In order to formulate flood management and control policies, a thorough understanding of flood problems and how it can be solved is required. This can be done through data collection and analysis along with flood impact assessment. This study attempted to develop an integrated approach of a new model for warning of floods rather than flood mapping for flood risk assessment in flood prone countries for regular monitoring of damages. Hydrodynamic model MIKE 11-FF (NAM, HD and FF) was successfully integrated with GIS in the Arc view GIS environment. MIKE 11 FF has been designed to predict the variation in discharges and water levels in a river system as a result of catchment rainfall and inflow/outflow through boundaries in the river system. GIS has been used intensively to create watershed models from digital elevation (DEM) data to trace flow-paths to get a complete surface for identifying the actual flood flow. Flood Affected Property: agricultural areas, population and infrastructure Flood inundation maps were being created by overlaying land use features and infrastructures to delineate flooded areas using dynamic spatial modeling. GIS was used for the analysis to determine hazard zones in the maps, which serve as risk zone identifiers for the general population. This information leads to locate safer location to evacuate the affected population utilizing the optimum route. Complete statistics will also be released for the predicted time stamps in advance by 72hrs, 48hrs and 24hrs. Finally, the information of population, land use and infrastructure are likely to be affected will be available in a user-friendly interface for timely decision for flood preparedness. |