Developing Flood Hazard Forecasting and Early Warning System in Dire Dawa, Ethiopia
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Date
2017-06
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Addis Ababa Universty
Abstract
Floods are one of the leading causes of destruction from natural disasters. Flooding causes major
stresses on the economic, social and environmental regimes. Structural and non-structural
measures are applied to prevent flood hazard destruction. Meanwhile, the flooding of August 5
2006 in Dire Dawa town demonstrated that structural measures undertaken so far are not
adequate to withstand flood threats. Non-structural techniques for preventing flood damage are
based on acceptance of flooding as a natural process that cannot be completely controlled. This
approaches focus on altering human behavior and awareness. In this study, flood hazard
forecasting and early warning system in Dire Dawa was developed using SCS-CN method, i.e.
one of the techniques under non-structural approaches. The developed system has seven
incorporated applications namely, initial abstraction analysis, maximum retention analysis, flood
analysis, antecedent moisture content calculator, curve number conversion, flood prone areas
analysis and messaging, and developed using C# object oriented programming language. The
study was carried out by using Landsat 7 ETM+ and Landsat 8 OLI satellite imageries of the
years 2005 and 2015, respectively, 15 m × 15 m digital elevation model and harmonized world
soil data for hydrologic soil group classification. Images were classified into classes using
supervised image classification. The results showed that 74.53% area of Dire Dawa town has
high value of CN, 10.21% is moderate and 16.07% of the town has low CN value, this implies
most part of the area has low maximum retention and initial abstraction value. A reliability
assessment of the system was conducted on the produced flood map of the first week of August
2006. The assessment result revealed that the system is fully functional for the intended
application.
Keywords: SCS-CN method, flood forecasting, early warning system, Dire Dawa.
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Keywords
SCS-CN method, Flood forecasting, Early warning system, Dire Dawa