Climate risks and adaptation in Asian coastal megacities: A synthesis

More documents

Recommendations

Info

Table 3.8 ■ Manila: Comparison of Inundated Area (km 2 ) with 1-in-100-year flood for2008 and 2050 Climate Change Scenarios with only ExistingInfrastructure and with Completion of 1990 Master PlanNo change to existing infrastructureAll 1990 Master Plan infrastructure implemented2008 (km 2 ) 2050 B1 (km 2 ) 2050 A1FI (km 2 ) 2008 (km 2 ) 2050 B1 (km 2 ) 2050 A1FI (km 2 )Pasig-Marikina 53.73 63.19 67.97 29.14 40.09 44.14West Mangahan 10.65 11.09 11.42 7.79 8.16 8.30KAMANAVA 18.24 18.24 18.24 — — —Total 82.62 92.53 97.63 36.93 48.25 52.44Relative increase 12.0% 18.2% 30.7% 42.0%Source: Muto et al. (2010).implementation of the 1990 Master Plan, infrastructurein the inundated areas will be reduced considerablyfor the current flood hazard (i.e., an inundatedarea of only 36.93 km 2 from a 1-in-100-year event in2008), but the infrastructure will not afford the levelof protection in 2050 for the return periods on whichthe designs are based. Climate change impacts underthe A1FI 1-in-100-year storm event would increasethe inundated area by 42 percent (from 36.93 km 2 to52.44 km 2 ) compared to the base year 2008. The mainpoint is that that the master plan will not offer theplanned level of protection.Increase in percentage of populationexposed to flooding under high and lowemissions scenariosAs would be expected from the significant increasein inundated area under the B1 and A1FI climatechange scenarios, the number of people affectedby the floods increases significantly as well, asillustrated in Figure 3.9. Thus, for a 1-in-100-yearflood in 2050, under the AIFI scenario more than2.5 million people are likely to be affected, assumingthat the infrastructure in 2050 is the same as inthe base year. In a scenario where the flood protectioninfrastructure under the 1990 Master Plan isimplemented, the level of protection expected by itsimplementation will not be achieved under the A1FI1-in-100-year storm event, where approximately 1.3million persons would be affected.An overlay of population density maps withGRID data on inundation shows areas of highFigure 3.9 ■ Comparison of PopulationAffected by Floodingunder Different Scenarios*3,000,0002,500,0002,000,0001,500,0001,000,000500,0000EX SQ EX B1 EX A1FI BAU SQ BAU B1 BAU A1FISource: Muto et al. (2010).* Scenarios include 1-in-100-year event (P100) in 2008 (SQ) with the 2050 B1and 2050 A1FI scenarios with only the existing infrastructure (EX) and with the fullimplementation of the 1990 Master Plan (business as usual or BAU).population density that are likely to face seriousflooding risk (Figure 3.10). These include ManilaCity, Quezon City, Pasig City, Marikina City, SanJuan, and Mandaluyong City.Areas in Metro Manila likely to be at highrisk from flooding due to extreme events in2050The hydrological analysis shows that some local governmentunits (LGUs) will be much more affectedthan others under different scenarios. As Figure 3.11shows, municipalities in the Pasig Marikina Riverbasin (namely Manila, Mandaluyong, and Marikina)and Kamanava areas (namely Malabon and Navotas)are more likely to be vulnerable to flooding comparedto those in the West Managhan area.36 | Climate Risks and Adaptation in Asian Coastal Megacities: A Synthesis Report
Figure 3.10 ■ Areas of High PopulationDensity and with HighRisk of Inundation underA1FI ScenarioImpact on roads, rail network, power andwater supply facilities and transportationThe hydrological analysis shows the length of roadsthat are likely to be flooded (in terms of depthand duration) under different scenarios. Thus forinstance, under both emissions scenarios—A1FIand B1, more roads are flooded under “existinginfrastructure scenario” where no additional infrastructuralimprovements are made, compared to ascenario where there is continued implementationof flood protection infrastructure in 2050 (Table 3.9).As a reference, it is useful to note that a depth ofmore than 26 cms is considered impassable for mostvehicles in Manila.The hydrological analysis also shows specificlocations where the power distribution system inManila is vulnerable. It notes that the elevated railsystem in Manila, although above the flood levels,is vulnerable to loss of power from the power utilityMerelco, and that a number of the stations wouldbe inaccessible during extreme floods. The impact ofhigh winds in these situations was not detailed. Theconsultants held discussions with the water supplyproviders who indicated that their facilities were notvulnerable to floods.Source: Muto et al. (2010).Figure 3.11 ■ Areas at High Risk from Flooding under Different Scenarios%80706050403020100CityMandaluyongManilaMarikinaQuezonSan JuanPassayMakatiPasigTaguigPaterosKalookanMalabonNavotasRegion Pasig – Marikina River Basin West Mangahan Area KAMANAVA AreaEx–SQ Ex–B1 Ex–A1F1 BAU–SQ BAU–B1 BAU–A1F1Source: Muto et al. (2010).Estimating Flood Impacts and Vulnerabilities in Coastal Cities | 37
Page 4 and 5:
© 2010 The International Bank for
Page 7 and 8: Figure 4.6 Damage Costs Associated
Page 9: AcknowledgmentsThis synthesis repor
Page 13 and 14: Executive SummaryIntroduction and R
Page 15 and 16: For each city, complex hydrometeoro
Page 17 and 18: infrastructure but a high emission
Page 19: these include strategies that focus
Page 23 and 24: policy implications have broader re
Page 25: 2Methodologies forDownscaling, Hydr
Page 28 and 29: Table 2.1 ■ Climate Change Foreca
Page 30 and 31: Return periods considered 18In this
Page 32 and 33: Figure 2.2 ■ Manila Rainfall-Runo
Page 34 and 35: Figure 2.3 ■ Estimation of Damage
Page 36 and 37: sion and distribution lines, and en
Page 38 and 39: Figure 2.5 ■ Possible Relationshi
Page 40 and 41: prices and the same prices are appl
Page 43 and 44: 3Estimating Flood Impactsand Vulner
Page 45 and 46: Table 3.2 ■ Bangkok Monthly Avera
Page 47 and 48: Estimation of storm surge in the ca
Page 49 and 50: Climate Change Impact and Adaptatio
Page 51 and 52: Figure 3.5a ■ Affected Condensed
Page 53 and 54: Manila’s current climate—Tropic
Page 55: Table 3.6 ■ Manila Climate Change
Page 59 and 60: is also a key economic and financia
Page 61 and 62: Box 3.3 ■ HCMC in 2050Future land
Page 63 and 64: original swamp land on which the ci
Page 65 and 66: from 68 percent to 71 percent; that
Page 67 and 68: Table 3.15 ■ Districts Affected b
Page 69 and 70: Table 3.16 ■ Effects of Flooding
Page 71 and 72: 4Assessing Damage Costsand Prioriti
Page 73 and 74: Table 4.2 ■ Summary of Flood and
Page 75 and 76: uilt outside the cities and are not
Page 77 and 78: ■■■■■■For the eastern p
Page 79 and 80: Table 4.6 ■ Flood Damage Costs Wi
Page 81 and 82: Table 4.8 ■ Flood Damage Costs in
Page 83 and 84: Figure 4.5 ■ Loss Exceedance Curv
Page 85 and 86: Box 4.3 ■ Increased Time Costs an
Page 87 and 88: Table 4.11 ■ Adaptation Investmen
Page 89 and 90: Marikina River areas through a dam,
Page 91 and 92: Table 4.14 ■ Present Value of the
Page 93 and 94: of reducing vulnerability of the po
Page 95 and 96: 5Conclusions andPolicy Implications
Page 97 and 98: open land use is expected to be flo
Page 99 and 100: hydrometeorological data, yielding
Page 101 and 102: BibliographyAllen, M. R., and W. J.
Page 103: Reduction: Inventory and Prospect.
Page 106 and 107:
a paper commissioned by JICA (Sugiy
Page 108 and 109:
mercial and industrial establishmen
Page 110 and 111:
ADB. The selection and prioritizati
Page 113 and 114:
AnnexCAdaptation to IncreasedFloodi
Page 115:
of people and institutions to manag
Page 120:
THE WORLD BANK1818 H Street, NWWash
show all

Climate risks and adaptation in Asian coastal megacities: A synthesis

Create successful ePaper yourself

Delete template?

Save as template?