Towards Integrated Urban Flooding Risk Management in Ambo Town and Its Watershed, West Shoa Zone, Oromia Regional State, Ethiopia
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Date
2021-09-01
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Addis Ababa University
Abstract
A GIS-based spatial planning and land use management is asserted to be a versatile tool in building capacities for flood disaster reduction and preparedness underpinning sustainable urban development.The purpose of the study was to analyze urban flooding hazard and risk and develop integrated urban flooding risk management strategy for Ambo town and its watershed. The study adopted a mixed research approch which combined quantitative and qualitative methods of data collection and analysis. The study confirmed that residing in flood prone area, poverty, lack of alternative livelihoods, and lack of proper drainage channels are the underlying causes of socio-economicvulner ability to urban flooding risk in Ambo town. Unwillingness of people to move away from hazard-prone areas due to the nature of their livelihoods, the high prices of properties, and a lack of awareness of the risk of hazards anticipated were identified as internal barriers to governance of urban flooding risk reduction in the study area. A strong positive association was confirmed between urban households’ perception on structural and non-structural measures practiced in Ambo town and their perception on the effectiveness of the current governance of urban flooding risk reduction. A statistically significant relationship was confirmed between respondents ’access to credit and their education level, total income, and employment status. A statistically significant relationship was confirmed between respondents’ perception on their vulnerability to disease after flooding risk and their demographic and socio-economic characteristics. 63.04% of the watershed is moderate flooding hazard area while 52.9% of Ambo town is moderate flooding hazard area. 20.2% of Huluka watershed is moderate flooding risk area while 21% of Ambo town is high and very high flooding risk area. The IDF curves developed indicate that rainfall intensities increase with increase in return periods for all the seven stations and the Huluka watershed. High rainfall intensities were confirmed to be related toshort durations while low rainfall intensities related to long durations for the same return periods. Bush and shrub land, forest, grassland, and water land use/land cover type declined with68.2%, 59.3%, 32.7%, and 5.1% respectively between 1979 and 2017. Based on the land use/ land
cover analyisis in the watershed, urban built-up area, cultivated land, and bare land use/land cover type increased with 351%, 105%, and 41.9% respectively between the year 1979 and 2017.Infrastructural and agricultural expansion, increased demand for wood, local environmental and biophysical drivers, rapid human population growth, economic drivers, technological drivers, policy and institutional drivers, and local socio-cultural drivers were identified as drivers of land use and xxland cover changes. There should be urban disaster risk reduction policies and strategies at national level which guide local urban disaster risk reduction interventions and the principles of good governance should be properly practiced in governance of urban flooding disaster risk reduction in Ambo town. It is vital to pay attention to the coordination between urban development and flooding hazard and risk through appropriate spatial planning and land use management in Ambo town and its watershed.
Keywords: Governance, flooding, land use/land cover, land use management, spatial planning