Assessment System of Socio-Economic impacts of Water-related Disasters for Infrastructure

1. Assessment System of Socio-Economic impacts of Water-related Disasters for Infrastructure 2010 Typhoon Committee Workshop 5-10 SEP 2010, MACAO

2. Purpose of Project Suggesting a scheme to construct an integrated assessment system of flood control measures Establishment of a scheme to select optimum economic flood control measures Construction of an assessment system applicable for members of the typhoon committee Constructing reasonable and integrated assessment system of flood control measures

3. Project Schedule Maintenance and utilization System, Inside module construction Framing the plans for maintenance and utilization Flood control assessment system Requirements analysis of users and analysis of structural measures D/B, module, and System, Damage Estimation and Economic module construction Module design of the system and module D/B design Present status analysis and establishment of plans 2011 Investigation of domestic and foreign flood control assessment system and establishment of plans 2010 2009 2008

4. Flowchart of Assessment System 1. Estimation flood discharge 2. Estimation flood stage at the watch point(channel routing) Yes 4. No Inundation No 5. Protected lowland flooding? 6. Potential flood damage=0 3. Bank height > flood stage ? 7. Inundation Yes 8. Estimation of the flood area & depth in the protected lowland 9. Estimation of the potential flood damage(Multi-dimensional flood damage analysis) 10. Repetition of the 1~9 procedures with each flood control measures 11. Selection of the optimal measure

5. System Contents(H/W, S/W)

6. Construction of flood damage data

7. Construction of flood damage data • Classification for Local characteristic • Human life damage in flood damage occurrence

8. The property D/B construction of flooding area • Economic index research by the administrative district • Local GDP research - Analysis results are notcorrect to use only population for classification index - Comprehensive indexes are population density and per GDP Per GDP Per GDP Population density

9. The property D/B construction of flooding area

10. The property D/B construction of flooding area • The spread of population & life expectancy investigation by administrative district • Use for casualty loss amount estimation

11. The property D/B construction of flooding area • The spread of population & life expectancy investigation by administrative district • Estimation of Casualty loss amount - Death + Injury+ Victim loss amount - Death loss amount= Flooding area(㏊) × Death rate of flooding area(per/㏊) × life expectancy(yr) × per GDP - Injury loss amount= Flooding area(㏊) × Injury rate of flooding area(per/㏊) × life expectancy(yr) × per GDP/ 2 - Victim loss amount= Flooding area(㏊) × Victim rate of flooding area(per/㏊) × evacuation day(day) × per GDP / 365(day)

12. Module construction of flooding area computation

13. Module construction of flooding area computation • Constuction to use various digital map from GIS basis • Administrative district map • DEM(1/5,000, 1/25,000) • Land use map - Use of satellite images • Computation through space information composition Administrative district Land use × Flooding area × Flooding depth Space information composition

14. Frequency based flood estimaton

15. Rainfall estimation Time distribution Flood estimation • Estimate probabilistic rainfall using established analysis results such as probable isohyetal charts • If it is not reliable or available, estimate the probabilistic distribution of rainfall • To use as the input of hydrologic model to simulate flood aspects, the probabilistic rainfall needs to be timely distributed • The methods such as Huff and Yen and Chow could be applied • Various hydrologic models such as HEC-HMS, HEC-1, ILLUDAS, SWMM could be used to simulate streamflow using the timely distributed probabilistic rainfall • Hydrologic model should be carefully selected with the features of applied basins Frequency based flood estimation

16. Frequency based flood estimation Rainfall estimation • The procedure of estimating probabilistic precipitation Normal, Lognormal, Gamma, Log-pearson type III, GEV, Gubel, Log-Gumbel, Weibull Meteorological data construction Applying probabilistic distribution Parameter estimation Maximum likelihood, Method of moments Goodness of fit test Colmogorov-Smirnov, Cramer-von-Mises, PPCC, x2 Selecting the optimum distribution Estimating probabilistic precipitation Huff, Yen and Chow 100-YEAR 1-HOUR RAINFALL Time distribution

17. Frequency based flood estimation Flood estimation Runoff simulation using hydrologic model (Ref. A guideline for the flood estimation of urban area, 2008)

18. Damage estimation system construction

19. Damage Estimation System Construction Provisional workflow diagram Socio-Economic analysis Initial setup and inputs Flood and damage estimation Initial setup Assets & maps Flood simulation Damage estimation Analysis Currency unit(₩,$,.) Area unit(m2, km2,.) Load basin map Set a flood simulation method Set the range of assets to estimate damage A Standards of damage loss - Actual recovery costs - National compensation costs Set the range of asset classifications according to map B Create cross sections of floodplain Set an analysis method Import simulated inundation with each flood control measures Create the tables of assets Generate HEC-RAS input Analyze the socio-economic values of flood control measures Input the tables or Use default values Run HEC-RAS Suggest the optimum measures A :Simulate flood inundation using HEC-RAS model Estimate the amount of loss for each flood control measures Generate floodplain and depth grid B : Import simulated inundation results from another model available for an applied basin

20. Damage Estimation System Construction Floodplain simulation • Model selection for the floodplain simulation • 1-dimentional • HEC-RAS • HEC-6 • HEC-2 • WSPRO • MIKE11 HEC-RAS • Simplicity of the model with the equivalent reliability • Familiarity with used technique • Running time • Types of computers • Availability of data • Model support and documentation • 2-dimentional • FESWMS • RMA2 • TELEMA-2D • MIKE21 • FIVFLOOD

21. Damage Estimation System Construction Floodplain simulation • River flood simulation using HEC-RAS • HEC-RAS iswidely used and accepted in particular for floodplain management and flood insurance studies (Karle, 2008) • HEC-RAS in the simulation of extreme glacial outburst flood is accurate enough for general flood protection purpose (Alho et al., 2008) • When more and more cross-sections were used, the simulation result of HEC-RAS was more similar to FESWMS 2D model (Cook et al, 2008) • The HEC-RAS and TELEMAC-2D models perform equally well in predicting the inundated area when calibrated, whereas the performance of the LISFLOOD-FP model is dependent on the calibration data used (Horritt et al., 2002)

22. Damage Estimation System Construction Floodplain simulation • Floodplain treatment in HEC-RAS (Tayefi et al., 2007) 1D-E • To Extend the cross-section across the full floodplain width • To comprise a series of discrete areas acting as storage cells for floodplain 1D-S

23. Damage Estimation System Construction Damage estimation standards • Total damage from flood • The total amount of cost to be paid to recover the socio-economic activities to the level possible if flood did not occur • Consisted of direct and potential damage Socio-Economic Activities Total damage Potential damage (Secondary damage) Direct damage (Primary damage) Flood occurrence Time

24. Damage Estimation System Construction Damage estimation standards • Direct damage (primary damage) • Destroyed constructions and agricultural area, damaged facilities and products, and injured people • Recoverable Damage (RD) - The cases of Constructions, facilities, and products that can be reconstructed or produced through paying cost - The standard of damage estimation is the cost to reconstruct and replace the damaged stuffs • Non-Recoverable Damage (NRD) - The cases of People, livestock, agricultural products that can not be replaced by simply paying cost - The standard of damage estimation in this case is the amount of loss Total Damage Recoverable damage Direct damage Non-Recoverable damage

25. Damage Estimation System Construction Damage estimation standards • Potential damage (secondary damage) • Damage During a Recovery period (DDR) - Costs engendered during a recovery from such cases as the interruption of production facilities, the inability of public facility, and the traffic jams caused by destroyed roads • Damage After a Recovery period (DAR) - As the example of a production facility deprived of buyers during a recovery, some facilities could have loss for their profit even though they have fully recovered for their facilities Total Damage Recoverable damage Direct damage Non-Recoverable damage Damage during a recovery period portential damage Damage After a recovery period

26. Damage Estimation System Construction Damage estimation standards • Additional cases of damage • Intangible damage (Grigg, 1975) - Some categories of intangible damage are: environmental quality, social well being, and aesthetic values • Uncertainty damage (Grigg, 1975) - The loss from uncertainty damage is from the stress of the occupants of a flood plain suffer because of the uncertainty with regard to when flood will occur and how serious it will be • Both intangible and uncertainty damage can be categorized as potential damage Total Damage Recoverable damage Direct damage Non-Recoverable damage Damage during a recovery period portential damage Damage After a recovery period Intangible & potential damamge

27. Damage Estimation System Construction Damage estimation • Procedure to estimate the flood damages by MD-FDA • The asset values and the ratio of each asset and inundated depth are used for estimating the amount of damage • Damage items are categorized into structures and contents in a residential area, farmland and crops in an agricultural area, tangible • assets and inventories in an industrial area, public facilities, and casualties Multi-Dimension Flood Damage Analysis (MD-FDA)

28. Damage Estimation System Construction Damage estimation • Casualties • To estimate the number of death and injury, the concept of ratio from the number of death and injury per area is used • The socio-economical loss of death is the function of life expectancy and GDP Loss of death = death per area (n/m2) × inundated area (m2) × loss per death ($/n) • The loss of injury is 50 % of the death according to the domestic law ofKorea. Thus the percent is flexible with the inherent standards of a applied basin for the severity ratio of injury to death The number of death and injury per flooded area (Unit: n/ha) (Ref. A study on the Economic Analysis in Flood Control Projects, 2004)

29. Loss of Structures = construction cost × destroyed area × deflator Damage Estimation System Construction Damage estimation • Structural and agricultural damage Loss of farmland = recovery cost × flooded area × depth damage rate Loss of crops = Value of crops × flooded area × depth damage rate × period damage rate × consumer price index Loss of contents = content cost × flooded area × depth damage rate × consumer price index

30. Damage Estimation System Construction Damage estimation • Estimation of the destroyed building • Through considering the historical record which shows destruction tendency of building for flood, the number of destroyed building for simulated flood can be estimated • Assumption • JeungSanMyeon • There are similar flood velocity and depth if the flooded location and area are the same • The number of destroyed building has a linear correlation with the flooded area • YangGum Dong • Mountainous area • Higher flood velocity could be expected • Historical record(2002/8) • Complete destruction 60 • Half destruction 69 • No destruction 0 • Urban area • Lower flood velocity could be expected • Historical record(2002/8) • Complete destruction 12 • Half destruction 14 • No destruction 2,188

31. Damage Estimation System Construction Damage estimation • Public facility damage • The damage ratio of public facilities to general assets is applied to estimated the amount of public facility damage The damage ratio of public facilities to general assets (Ref. A study on the Economic Analysis in Flood Control Projects, 2004)

32. Thanks for your attention !!