Development of flood warning system
Flood Mitigation
Flooding cannot be completely avoided, but damages from severe flooding can be reduced if effective flood prevention scheme is implemented. This can be achieved if the sufficient information for flood forecasting is acquired both in time and in quality. Hydrologic applications of GIS range from synthesis and characterization of hydrologic tendencies to the prediction of response to hydrologic events. The payoff comes from the multiple ways in which the data can be used once it is made to be digitally accessible in a GIS (Tawatchai, 1999). Use of GIS will provide supplementary data in Hydrology for such analysis and will lead to easier interpretation and understanding of flood phenomena and characteristics. The use of Digital Elevation Model (DEM) can be effectively used for simulation to get a complete model of the study area. The objective is to develop an effective flood warning system integrating GIS, hydrologic models, emergency response strategies, and expert knowledge into the system.  Fig.1: Development of flood warning system Study Area Sundarganj Thana of Gaibandha district in Bangladesh has been selected as my study area. It is located in the northern part of the country. Two major rivers bound Sunderganj, Brahmaputra (Jamuna) in the eastern and Teesta in the northern part of Bangladesh. Total area is 418.74 Sq. km and population is 364,432. Sunderganj thana consists of 15 unions and Tarapur is one of them. The size of urban area of Sunderganj thana is 5.0 Sq. km, whose population is 9, 940. Area of household in Tarapur union is 6.42 Sq. km; population is 25,796(Source: BPC, District: Gaibandha, June 1994) Floods in Sunderganj The area is subjected to flood almost every year from both rivers the Teesta and the Brahmaputra, with both beneficial and adverse effects. The river Teesta causes flash flood, monsoon flood is caused by the river Brahmaputra. 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. The rivers in the extreme northern area (Teesta, Dudkumar and Dharla) have steeper gradients (1 in 2000) than elsewhere and most of their catchments lie in India and Bhutan. They frequently cause flash floods. The part of the region along Brahmaputra suffers severely from river flooding caused by breaches, mainly in the main Brahmaputra River and to limited scale in the Teesta River. Inside the region, flooding and drainage patterns of the internal rivers which have catchment areas basically within Bangladesh and have very flat gradients of 1 in 5000. Internal rainfall flooding is therefore common. The severity of flooding may be exacerbated by rainfall within the region. The region experienced a devastating rainfall floods in September-October 1995. Such severe rainfall flood also occurred in 1922. (Source: International Commission on irrigation and Drainage, Bangladesh national Committee of ICID) |