Impact analysis of flood in Accra, Ghana

Abstract

Within the past decades, flooding has become a global pandemic, which hampers economic and social development. This global phenomenon has led to loss of lives and economic damages in many countries including Ghana. On June 3rd 2015, Accra, Ghana's capital experienced an unprecedented flash flood event, coupled with an explosion at a Goil filling station that resulted in a death toll of over 152 lives. It is therefore necessary to explore new ideas and approaches that can be incorporated to existing structures to manage this problem. The aim of this study is to analyse the underlying causes of flood in Accra, examine the suitable structural measures that can be undertaken to mitigate flood impacts in Accra, and propose a mitigation approach to manage flood impacts using Integrated Flood Risk Management and Sustainable Flood Management. The Intensity of rainfall events in eight drainage basins in Accra namely; Kpeshie, Korle, Densu, Sakumo, Lafa, Osu, Songo Mokwe and Chemu triggers flash floods due to a short response time and high specific peak discharges. Precipitation patterns in Accra have changed considerably within this few decades. According to IPCC scenario B1, A1B, and A2 forecasting, there will be an increase in the average monthly precipitation from 160 mm in 1991-2010 to 200 mm in 2011-2020 respectively. A ten (10) year flood protection level was employed to model the rate of urban damage, estimate affected Gross Domestic Product (GDP) and the population at risk in Accra