Climate risks and adaptation in Asian coastal megacities: A synthesis

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15°N10°NThis map was produced by the Map Design Unit of The World Bank.The boundaries, colors, denominations and any other informationshown on this map do not imply, on the part of The World BankGroup, any judgment on the legal status of any territory, or anyendorsement or acceptance of such boundaries.120°E 125°E5°N 120°E125°E5°N15°N10°Npalities. It is a low-lying area crisscrossed by thePasig River and its tributaries, which flows northwestwardfrom Laguna de Bay, the largest lake inthe Philippines, to Manila Bay in the west. MetroManila lies on a swampy isthmus and is markedby three quite diverse hydrological characteristics.These include the Pasig Mariquina area, Kamanavaarea, and the west of Managhan area facing theLaguna de Bay (Figure 3.6). The Pasig Mariquinaarea has several river systems and a catchment areaof 651 sq kms. It includes 10 cities/municipalitiesof Metro Manila. The Kamanava area along thelow-lying coast is flat, prone to typhoons, and haselevations ranging from around sea level to 2–3meters above sea level. Before the 1960s, it mainlyconsisted of lagoons, but has been filled up and currentlycomprises commercial districts, residentialareas, and fishponds. The West of Managhan areais 39 square kms and covers five cities. There area number of drainage channels draining into theLaguna Lake or Napindan River.Importance of Metro Manila to the regionaleconomyFigure 3.6 ■ Metro Manila and itsWatershedJANUARY 20100 5KILOMETERS14°40'MANILAManilaBayBacoor121°00'MeycauayanCaloocanPasig RiverMandaluyongParañaque121°00'San JoseDel MonteSan JuanQUEZONCITYPaterosTaguigMarikinaPasigR iverMarikinaLagunaBayRodriguezSan MateoSource: Philippines map IBRD 37476.AntipoloBinangonanBosobosoLagunaBayPililla121°20'PHILIPPINESPASIG – MARIKINA RIVERS121°20'MALAYSIATuguegaraoSan FernandoBaguioSan FernandoMANILA QuezonArea of MapSulu SeaPROJECT RIVERSWATERSHEDSELECTED CITIESREGION CAPITALNATIONAL CAPITALIloiloZamboangaIliganCotabatoCelebes SeaLegaspiTaclobanCebuREGION CAPITALSNATIONAL CAPITALREGION BOUNDARIESINTERNATIONALBOUNDARIESPhilippineSeaButuanCagayande OroDavaoIBRD 37476Like Bangkok, Manila is also a capital city and amajor economic center. It is located on the easternshore of Manila Bay, on the western side of theNational Capital Region. It is a central hub of thethriving Metropolitan Manila area. With a populationof 11 million, it is ranked as one of the mostdensely populated cities in the world. The PasigRiver bisects the city in the middle before draininginto Manila Bay. Metro Manila, the broader urbanagglomeration, has the highest per capita GDP inthe country. In 2007, its population was estimated tobe over 20 million people. In 2008, it was ranked asthe 40 th richest urban agglomerations in the world,with a GDP of $149 billion, indicating the economicimportance of Metro Manila. Manila is also a majortourist destination, with over 1 million tourists visitingthe city each year.Unregulated expansion into fragile areasand informalityWith large in-migration and rapid populationgrowth, the city expanded to the suburbs, surroundingmunicipalities, and to areas risky forhabitation (e.g., swampy areas, near or above esterosor water canals, along the river or earthquakefault lines, etc.). A large part of the developmentsin informal settlements are unregulated. Manystructures are built on dangerous and risky areas,such as near the seashore or flood zone, or onground prone to landslides. Socioeconomic factorslike land use practices, infrastructure development,building standards/codes and practices, and urbandevelopment policies and programs have greatlyshaped the settlement and building patterns of thecity. These forces generate an environment thatposes high risks to residents and infrastructurealike, especially in the low-lying flood-prone areas.As in other cities in developing countries, there aresignificant wealth disparities in Manila that arereflective of the country as a whole, with 97 percentof GDP controlled by 15 percent of the population(WWF 2009). Within Metro Manila, 10.4 percent ofthe population in lives below the poverty line, accordingto 2006 official statistics. 32 Approximately61 percent of the population in Metro Manila doesnot have access to basic services, according to the2008 Philippine Asset report report card (citedin Manila study). There is an estimated housingbacklog of almost 4 million.32http://www.nscb.gov.ph/poverty/2006_05mar08/table_2.asp32 | Climate Risks and Adaptation in Asian Coastal Megacities: A Synthesis Report
Manila’s current climate—Tropical withdistinct wet and dry seasonsFigure 3.7 shows the four main climate regimesin the Philippines and the relative frequency oftyphoons making landfall. Manila falls into Type1, which is defined as having two distinct seasons,with the dry season running from November toApril and the wet season occurring in the othermonths. About 16 percent of the typhoons crossingthe Philippines pass in the general vicinity of Manilaand its nearby areas. The average temperaturesand precipitation in Manila are shown in Table 3.6.Manila has an average annual precipitation of about1,433 mm, but there is significant variability.Main climate-related drivers of flooding—driven by single-storm events, usuallyrelated to typhoonsFigure 3.7 ■ Different ClimaticRegimes in the PhilippinesTable 3.6 ■ Manila: Monthly AverageTemperature andPrecipitationMonthTemperatureAverage Low( o C)TemperatureAverage High( o C)Averageprecipitation(mm)January 24° 30° NegligibleFebruary 24° 30° 12.1March 25° 32° 9.1April 27° 33° 15.9May 27° 33° 133.0June 26° 32° 150.8July 26° 31° 292.9August 26° 31° 305.8September 26° 31° 237.5October 26° 31° 137.2November 25° 31° 81.3December 24° 30° 58.0Total 1433.6Source: http://weather.uk.msn.com/monthly_averages.aspx?wealocations=wc:RPXX0017Unlike Bangkok, where floods are generated byheavy seasonal precipitation over 1 to 3 months,extreme flood events in Manila are caused by heavyprecipitation events over 1 to 3 days generally associatedwith typhoons and storm surge. The watershedarea for Manila’s Pasig-Marikina River System is651 km 2 , which includes the San Juan River catchment.This is relatively small in comparison to thewatersheds of other cities in the study. The precipitationpattern causing flooding is often associatedwith strong winds and flash flooding, which canbe devastating for informal housing located alongdrainage ways. Seeking refuge during such events isextremely difficult and hazardous to the population.Other climate-related factors contributing to floodinginclude a combination of high tide, excess runoff fromrivers, heavy rains, and sea level rise. A schematic ofthe watersheds around Manila is shown in Figure 3.8.Non-climate related drivers of flooding!Even though land subsidence is an important issuein Metro Manila, it was not possible to consider itfor the hydrological simulation for the Manila studybecause of lack of availability of reliable data. 33 TheSource: Muto et al. (2010).33One difficulty in Metro Manila is that the station that issupposed to measure land subsidence of Manila de Bay islocated on one of the old piers of Manila Port, which itselfis sinking gradually.Estimating Flood Impacts and Vulnerabilities in Coastal Cities | 33
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: Figure 3.5a ■ Affected Condensed
Page 55 and 56: Table 3.6 ■ Manila Climate Change
Page 57 and 58: Figure 3.10 ■ Areas of High Popul
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
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Climate risks and adaptation in Asian coastal megacities: A synthesis

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