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Development of flood warning system
Farah Aziz, Nitin Tripathi, Mark Ole and Michiru Kusanagi
Asian Institute of Technology, Bangkok, Thailand
nitinkt@ait.ac.th
Abstract
Bangladesh is considered to be a country miserably affected by recurring floods with devastating dimensions exposing the national economy in the hands of nature. Complete flood control in the geographical context, particularly in the deltaic form of Bangladesh is not at all a feasible option. Structural methods of flood protection are neither economically viable nor these are environment friendly. Therefore, non-structural methods are becoming popular in mitigating flood disaster. A good way to prevent/ reduce damages occurred from flood is to develop a Flood Forecasting and Warning System in the affected area. This study is an attempt to fulfill such requirement by the extensive use of GIS, providing spatial information for assessment of flood vulnerability.
A methodology is developed by integrating Danish Hydrodynamic Model MIKE 11 and GIS. The MIKE 11 flood forecasting system comprising of three modules of NAM, HD and FF. FF module is used for flood foresting. The Geographic Information System (GIS) in this has proven to be a very effective tool for describing, analysing, modeling and integrating forecasted flood levels with other related information such as topographic, thematic and attribute information. It offers new opportunities to develop and implement a user-friendly, interactive decision support system for flood forecasting and identifying the affected areas using dynamic spatial modeling.
The study concludes that an effective Warning System that can release warning in advance, i.e. 72hrs, 48hrs and 24hrs. It can change the existing scenario substantially and render informed decision making in adopting proper measures towards disaster preparedness, mitigation, control, planning and management. This kind of advance warning can help the authorities for better flood preparedness and also effective flood mitigation.
Introduction
Floods are the major disaster affecting many countries in the world year after year. It is an inevitable natural phenomenon occurring from time to time in all rivers and natural drainage systems, which not only damages the lives, natural resources and environment, but also causes the loss of economy and health. The impact of floods has been increased due to a number of factors, with rising sea levels and increased development on flood plain (Sanders and Tabuchi, 2000). Recurring flood losses have handicapped the economic development of both developed and developing countries.
Damage from flooding has been increasing each year resulting in loss of lives, property and production as well as affecting activities in the flooded areas. Large and long duration of flooding can be considered as the economic loss of the country. The non-structural methods of mitigation of flood hazards are very cost effective as compared with structural ones (dams and dikes). Among non-structural methods, modern flood forecasting and the association with real-time data collection systems have increasingly found favor with countries prone to flood hazards. Flood risk mapping is required to provide information concerning flood risk areas to residents in flood prone areas and to establish flood protection and evacuation system. In determination of Decision Support System for flood risk assessment, it is of utmost importance to apply the most efficient methods in flood forecasting and warning system associated with real-time data collection system. (Sirivilal Kanchanaham, 1997)
From Bangladesh perspective, floods are among the most regular and hazardous natural disasters in terms of human suffering and economic losses. It has been identified that, timely flood forecasts and warnings are key elements to aid disaster preparedness, which in turn will reduce flood damages and human sufferings in a great extent.
The existing systems of collecting information on floods extent and their effects are not very reliable. The system depends heavily on field information, which sometimes is erroneous and at times cannot even be collected until the recession of the floodwaters (EGIS, Dhaka, June 1998). Information from GIS can be used to extract some types of information, which are otherwise difficult to access by traditional methods, particularly for flood-forecasting and floodwater movement. This present study implies the application of Geographic information Systems technologies to develop a new model for forecasting floods rather than flood mapping for flood risk assessment in flood prone countries for regular monitoring of damages. The importance of the flood forecasting and warning is widely recognized as a vital non structural measures to aid the mitigating the loss of life, crops and property caused by the annual flood occurrence.
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