chapter 4 - DRK

Strictly under embargo until Wednesday 22 September at 00:01 GMT (02:01 Geneva time)Table 2.2 Port cities with population over 1 million estimated to have highest increasedpopulation exposure to surge-induced floods, 2005 to projected 2070CityCountryPopulation2005 (000s)Populationexposed 2005(000s)Populationexposed 2070(000s)IncreaseQuingdao China 2,817 88 1,851 2,103%Luanda Angola 2,766 1 18 1,800%Dhaka Bangaldesh 12,430 844 11,135 1,319%Mogadishu Somalia 1,320 9 115 1,278%Conakry Guinea 1,425 41 496 1,210%Chittagong Bangladesh 4,114 255 2,866 1,124%Ningbo China 1,810 299 3,305 1,105%Dar-es-Salaam Tanzania 2,676 36 351 975%Yangon Myanmar 4,107 510 4,965 974%Karachi Pakistan 11,608 49 473 965%Douala Cameroon 1,761 11 101 918%Lagos Nigeria 10,886 357 3,229 904%Kulna Bangladesh 1,495 441 3,641 826%N’ampo Republic of Korea 1,102 22 181 823%Port-au-Prince Haiti 2,129 1 8 800%Source: Nicholls et al. (2008)Vision three: City-level data for multi-hazardsThe DesInventar database offers a finer scale of data, with greater information at thelocal level, portraying a more detailed reality of risk facing cities and urban dwellersincluding small-scale events and everyday hazards.Using the city-level database from Cali, Colombia and plotting the events geographically,it is possible to see how the location of flooding events changes over time (see Figure 2.6).The details from Cali (analysed by Colombia’s Seismic Observatory of the South-West orOSSO) show how the pattern of flooding events is related to informal urban expansionin low-lying areas along the rivers, and to subsequent improvements in infrastructureover time. In Cali, risk patterns for small flood events expand concentrically from thecentre of the city outwards to the periphery following the expansion of informal settlements.Additionally, small pockets of risk may be found in central areas ignored byformal urbanization, such as riverbanks and steep slopes.Case studies of cities in Argentina, Costa Rica and Mexico also support the findingsfrom Cali, showing how extensive risk is generated through urban expansion and closelylinked to increased run-off from new urban development, chronic underinvestment incity-wide storm and surface drainage, location of informal settlements in flood-proneareas and inadequate water management for wider watersheds. It is likely that urban42