African Water Development Report 2006 - United Nations Economic ...

fact that in recent times drought-related mortalityhas been almost non-existent in the absenceof conflict, speaks for the success of internationaland local efforts to mitigate drought.Vulnerability to RiskExtreme hydrometeorological events such asflooding and drought are common across Africa,while geophysical events such as earthquakes occurpredominantly in Northern Africa, along theAtlas mountain range, and in the African RiftValley which also experiences volcanic activity.The ENSO causes significant climatic disturbancesin most parts of Africa, either inducingdrought or flooding or increasing sea temperatures,leading to cyclones. These natural eventslives in arid areas, compared to just 2 per cent ofEurope’s population (Findlay 1996).MANAGING RISKSFigure 10.5: People affected by natural disasters between 1971-2000Source: UNEP – Vital Water Graphics, 2005become disasters where large numbers of peopleor infrastructure are affected, as has occurred overthe past 30 years due to high population growthrates, especially in urban centres and droughtproneareas - 34 per cent of Africa’s populationMost cities and population centres in Africa liein flat terrains and hence are generally devoid ofnatural drainage systems. Urban drainage systems,where existent, are left unattended to makingmost parts to malfunction, especially duringlong spells of droughts. One other importantfeature of the physiographic conditions of thepopulation centres is that they are mostly surroundedby highlands sometimes accentuated byunidentifiable and un-gauged ephemeral streamchannels which in times of intensive rainfallconduct torrential flash flows towards residentialareas. The devastating effects of the floods causedby direct rainfall superimposed on the torrentialflows in ephemeral stream channels on populationcentres are responsible for most of the directdamages caused in urban centres during extremeevents (Andah, 1988).237