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

African Water Development Report 2006Flood ManagementMuch of Africa is vulnerable to flooding: flood isthe most prevalent disaster in North Africa, thesecond most common in East, South and CentralAfrica, and the third most common in WestAfrica. Episodes of flood accounted for 26 percent of total disaster occurrences in Africa during1971-2001 (Vordzorgbe 2003 B) with devastatingeffects. In North Africa, the 2001 disastrousflood in northern Algeria resulted in about800 deaths and economic loss of about $400million. In East Africa, the El Niño-relatedflood in 1997/1998 destroyed infrastructure andproperty worth about $1.8 billion in Kenya. InMozambique, the 2000 flood, (worsened by twocyclones) reduced the annual economic growthrate from 10 per cent to 4 per cent, caused 800deaths, affected almost 2 million people of whichabout 1 million needed food, displaced 329,000people and destroyed agricultural productionland, among other negative effects. The singleworst episodes of flood in Africa occurred in EastAfrica: one in 1997 which killed 2,311 people inSomalia and the other in 1999 which affected1.8 million people in the Sudan.Structural and non-structural measures for managingthe direct effects of floods, includes, asstated by Vordzorgbe, S. D(2003):(a) Risk assessment of floods and early warning:these are essential in determining the likelihoodand duration of occurrence of floods,as well as the extent and location of damage.Subregional systems for early warningof flood exist in the SADC and Sahelsubregions and are being developed in theGreat Horn. However, water resource variability,river flow and hydrological modelsare at various stages of development at thenational and subregional levels throughoutAfrica to serve as precursors to comprehensiveflood early warning systems;(b) Integrated development, including land useand disaster response planning to minimizethe damaging effects of floods, particularlyflash floods. However, this is one of the areasof flood control in Africa in which actionis weakest;(c) Development of physical flood controlstructures, mainly as part of public investmentprogrammes. This is an essentialflood-protection measure, but the highlevel of investment required has made thedevelopment of these structures grossly inadequate,particularly in disadvantaged urbanlocations;(d) Development of flood maps to provide informationon the past, likely or potential extentof flooding which (sometimes in combinationwith other related information)help in making decisions on various aspectsof integrated management of floods;(e) Incentives to encourage people to constructsafe structures;(f ) Risk awareness to induce people to be increasinglyresponsible for their own safetyand to improve their compliance withwarning advice and response recommendations;(g) Environmental management to minimizeenvironmental factors that exacerbatefloods.238