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Accueil du site → Master → Pays Bas → 2009 → Flood risk assessment, prediction and control measures on the Middle Awash River, Ethiopia

UNESCO-IHE Institute for Water Education, Delft (2009)

Flood risk assessment, prediction and control measures on the Middle Awash River, Ethiopia

Haile, D.B.

Titre : Flood risk assessment, prediction and control measures on the Middle Awash River, Ethiopia

Auteur : Haile, D.B.

Université de soutenance : UNESCO-IHE Institute for Water Education, Delft

Grade : Master of Science (MS) 2009

Flooding is a natural and recurring event and often causing severe damage to propertyand agriculture, disruption to the economy and society, and even result in loss of life.The trends in flood risk are increasing due to an increase of population, rapidurbanization and new developments, changes in land use, environmental and climatechange, as well as an increase of vulnerability of structures in the flood prone areas.In Ethiopia, floods are relatively common during the wet season between June andSeptember, following intensive and long duration rain events. Especially the lower andthe middle basin of the Awash River are highly susceptible to flooding and arefrequently flooded by the overflowing of the river over its banks onto adjacent lands.Due to the recurrent flooding in the basin, a number of people have lost their life, theagricultural plantations are often destroyed, houses and infrastructure are destroyed andthe normal livelihoods of communities disturbed.This study is focuses on the Middle Awash River basin Ethiopia focusing on the reachof the Awash River near the town of Metehara. The analysis of flood risk is conductedwith the help of a hydrodynamic model. A 1D-2D Sobek - Rural hydrodynamic modelis used for this research to carryout the flood risk assessment in the area. As input datafor the model, the Digital Elevation Model (DEM) of the area was generated by usingArc View GIS tools, the upstream and downstream boundary conditions are computedfrom the available hydrological data of the river. The model is used to simulate andpredict the inundation processes through the determination of water levels anddischarges for different return periods.Based on the hydrological data of the area, the flood extent maps and consequences offlooding, a method for estimating flood damage is established. This method is theHydro-Economic Expected Annual Damage (EAD) and although it is applied only inthe study area, it can be used as guidance for flood risk estimation in flood prone areasin Ethiopia. In addition this method enables a balanced assessment the causes and effects of flooding in the area and helps to provide an appropriate flood defence strategy. The study also incorporated the impacts of developments on flood prone areas on theflood risk. In addition the possible structural and non structural measures are provided that can be taken to reduce overall flood risk in the area. For the area of Metehara it wasfound that the most effective strategy is regulating a10 years return periods flow andwater level since the relative increment of expected annual damage cost is the highest at10 years return periods flow.

Sujets  : flood risk assessment floods river basins simulation modelling Ethiopia


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