Climate risks and adaptation in Asian coastal megacities: A synthesis

More documents

Recommendations

Info

Figure 2.3 ■ Estimation of Damage to Buildings, Assets, and Inventories in theBangkok and Manila Cases1Identify buildings inflooded areas usingbuilding /infrastructuresurveys.2Classify buildings intocommercial, industrial,residential or othersub-classifications.3Identify assets andinventories in buildingsbased on surveysor on the type ofbuilding.4Establish average valuesof buildings andassets/inventoriesbased on tax information,industrial surveys,householddurable wealth dataetc.5Apply a damage rateto different buildingsand assets/inventoriesto establish actualdamage at differentlevels of flooding. Thedamage rate isobtained from previousflood informationor from secondarysources and varies withthe level of floods.buildings. The steps used in estimating damagecosts in the case of Bangkok and Manila are identifiedin Figure 2.4.Identifying, classifying, and valuing damageto buildingsThe Bangkok and Manila case studies used informationfrom building censuses and other infrastructure-relatedstudies to classify buildings first intoresidential, commercial, and industrial buildings.Based on national statistical organization classifications,these categories of buildings were furthersubdivided. For example, commercial buildingsalone were subcategorized into nine groups in thecase of Bangkok.Once buildings were classified into differentsubgroups, they were valued based on availablegovernment data. The Bangkok case study identifiedthe book values of buildings of different typesbased on construction costs when the buildingswere legally registered. These values were thendepreciated to reflect aging. In Manila, the baseunit construction cost of residential and commercialbuildings was obtained from the governmentassessor’s office and the median value of differenttypes of buildings estimated. Then, based on theestimated depth of floods (output from the hydrologicalanalysis), the value of floor areas of floodaffectedbuildings was identified.In order to estimate the actual cost of damageto buildings, the case studies used different damagerates depending on the level of the flood. 24 The damagerate or the percent of the value lost from floodsis dependent on the depth of inundation. A differentrate is applied to assess damage to buildings anddamage to assets. The Bangkok study used a 1997survey to establish damage rates; the rate was usedfor all types of buildings and housing (residential,commercial, and industrial). The Manila study useddamage rates, which vary across buildings and assets.Assets such as machinery, office furniture,and inventory damaged by floods also need to bevalued. The loss of assets from damaged buildingswas evaluated based on “representative assets”in different types of buildings. For example, inthe case of the Bangkok case study, average assetvalues obtained from census data for buildings areTHB 328889 ($9,873) for Bangkok and THB 220180($6,609) for Samut Prakarn. In the Manila study,the value of stocks, assets, and inventories of commercialand industrial enterprises was obtainedfrom the National Statistical Organizations’ data of24The flood damage rates used in the case studies were obtainedfrom either local surveys or from secondary sources.14 | Climate Risks and Adaptation in Asian Coastal Megacities: A Synthesis Report
establishments. A damage rate (Table 2.4) was appliedto assets and inventories to determine losses.The Bangkok study used a similar approach.To estimate losses to residential assets, the valueof household goods first needs to be established. Inthe Manila case, the value of household effects wasestimated to be 35 percent of the value of residentialconstruction costs of flooded buildings. Similarly, finishingswere estimated to be 25 percent of constructioncosts. In the Bangkok study, average householdassets or durables were obtained from the Populationand Housing Census of 2000. The value of theseassets was based on market prices. Once the assetvalues were obtained, damage rates were used toestimate the losses from different levels of flooding.Assessing impacts on roads andtransportation networksFlooding affects road and train networks in all thecities. There are direct and indirect costs associatedwith loss of transportation infrastructure. Directcosts are (a) construction or repair costs; and (b)any losses of vehicles or damaged trains and so on.These costs are estimated where applicable, basedon average repair costs. Indirect costs associatedwith damage to transportation infrastructure includeincreased vehicle operations costs (VOC) resultingfrom damages to roads from flooding or because ofchanges in traffic pattern (increased petrol costs), ortime costs from losses in productivity (ECLAC 2003).More than 90 percent of inhabitants of Bangkokand Samut Prakarn travel by roads and highways.However, the road network in Bangkok, SamutPrakarn, and the BMR are set at an elevation of1.5–2.0 meters above ground, and most of themare covered with reinforced concrete pavement or7–10 cm of asphaltic pavement. Therefore, they arenot expected to incur flood damages. Rail lines aregenerally set at about 1 meter above the surroundingground level. The Bangkok rapid transit system,both elevated and underground, has been designedto be protected from overflow flood water. Thus,the costs associated with transport networks fromflooding in Bangkok are expected to be minimal.The Manila study undertook a detailed analysisof damages to the transport sector. First, based onthe transport master plan, future road constructionTable 2.4 ■ Flood Damage Rate by Typeof Building in ManilaType of BuildingAffected AssetsFlood Level100–200 cm 200–300 cmResidential Finishings 0.119 0.58Household Effects 0.326 0.928Business Entities Assets 0.453 0.966Stocks 0.267 0.897Source: Adapted from Manual on Economic Study of Floods, JapanNote: Damage rates are available for less than 50cm and more than 300 cm as wellwas identified. The length of major and minor currentand future roads likely to be affected by floodswas then established. Based on unit maintenancecost data from the Department of Public Worksand Highways, the cost of maintaining these floodaffectedroads was estimated. The Manila study alsoestimated indirect costs from flooding related totime delays from traffic disruptions and problemswith vehicle operations. In the Manila case, thevehicle operations cost (VOC) is obtained from theDepartment of Public Works and Highways and includesfixed costs of operating vehicles and runningcosts. The costs of floods or the change in VOC perkm was estimated as the difference between VOCon flooded roads and on roads in good condition.This difference in VOC is multiplied by the numberof affected roads in 2008 and 2050 to obtain damagecosts in these two periods. To estimate time-delaycosts, data on flood related transport delays andthe number of road commuters were obtained fromsecondary sources and transportation surveys. 25The number of commuters delayed by floodingwas then multiplied by average hourly income asa proxy for time costs.Assessing direct and indirect costs inenergy, water supply and sanitationEnergy, like the transportation sector, may sustaindirect and indirect damages from floods. Directdamages to electricity generation plants, transmis-25The Manila study draws heavily on the government’sTransport Master Plan, which lays out potential transportationchanges up to 2015, and on the Metro Manila UrbanTransportation Integration Study (MMUTIS).Methodologies for Downscaling, Hydrological Mapping, and Assessing Damage Costs | 15
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 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 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
show all

Climate risks and adaptation in Asian coastal megacities: A synthesis

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?