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ANALYSIS OF FLOODING IN URBAN AREAS, TAKING INTO ACCOUNT THE RESIDENCE TIME OF THE WATER ON

SITE CASE OF STUDY: VERACRUZ, MÉXICO. Faustino De Luna C 1, Oscar A. Fuentes M 1, Laura Vélez M 1and Ismene L. A. Rosales Plascencia 2

1 Instituto de Ingeniería, Universidad Nacional Autónoma de México, México 2 Universidad Autónoma Metropolitana Unidad Azcapotzalco, Azcapotzalco México D.F.

FLunaC@iingen.unam.mx, ofm@pumas.iingen.unam.mx, LVelezM@iingen.unam.mx

Objective

Warning the repercussions of the residence time of water in the study area, also the damagecaused to homes by floods.

Mathematical model and Mathematical model results

To give a solution, we propose a method of finitedifferences. For the application of the mathematicalmodel were written several computer programs inVisual Basic language. The application of computerprograms was exhaustive and it was necessary tosimulate many possible options to define hydraulicconditions for various probabilities of occurrenceoverflow flooding rain river basin. Digital elevation model in the study area

17TH - 21ST OCTOBER 2016, LYON, FRANCE

3 RD EUROPEAN CONFERENCE ON FLOOD RISK MANAGEMENT

INNOVATION ♦ IMPLEMENTATION ♦ INTEGRATION

4. CONCLUSIONS

5. REFERENCES

Baeza, R. C. (2007). “Estimación regional defactores de convectividad para el cálculo de lasrelaciones intensidad-duración-frecuencia”.Tesis de Maestría. Universidad NacionalAutónoma de México.Baró, Suarez José Emilio. “Costo más probablede daños por inundación en zonashabitacionales de México”, septiembre 2011.Chen, C. L. (1983). Rainfall Intensity-Duration-Frequency Formulas. Journal of HydraulicEngineering, ASCE, Vol. 109, No. 12, December1983, pp. 1603-1621.Chow, V. T. (1994). “Hidrología Aplicada”.McGraw-Hill Interamericana, S.A., Colombia.

CENAPRED, (2004).”Guía Básica para laelaboración de Atlas Estatales y Municipalesde Peligros y Riesgos”, 1ª Edición Diciembre2004.Fuentes, M. O. A. (2012). “Obtención dehietogramas correspondientes a diferentesperiodos de retorno”, XXV CongresoLatinoamericano de Hidráulica, San José, CostaRica.Maidment, D. R. (1993). Handbook ofHydrology. McGraw-Hill Inc., USA.Metodología para la Elaboración de Mapas deRiesgo por Inundaciones en Zonas Urbanas.Centro Nacional de Prevención de Desastres.Serie: Atlas Nacional de Riesgos. Fenómenos

Hidrometeorológicos. Marco Antonio Salas,Julio 2011.OMM, Gestión Integrada de Crecidas:Documento Comceptual. OrganizaciónMeteoorológica Mundial. OMM-No.1047.Ginebra, Suiza 2009.OMM, Tercera Conferencia Mundial sobre elclima, Ginebra, Suiza, 31 de agosto-4 deseptiembre de 2009.Paoli, Carlos U. Curso Gestión Integrada deCrecidas, Facultad de Ingeniería y CienciasHídricas-Universidad Nacional del Litoral.Centro Regional Litoral-Instituto Nacional delAgua.-Prof. Ing. Carlos U. Paoli, Santa FeArgentina, 26 al 30 de abril de 2010.

Flooding in the lower part of the basin is generated by the overflowing of rivers, due to runoff in theupper area in the basin, the result of extreme rainfall by the presence of weather events, such astropical cyclones and cold fronts, the rain produces, in the lower area, not drained efficiently, andwhen the Jamapa leads an important river flow due to the slope of the terrain.

Not necessarily, the works that are constructed reduce flood damages. Sometimes the water thattemporarily occupied an area of land can be moved to other regions where it could cause furtherinjury; therefore, it is convenient to carry out comprehensive studies of a whole watershed to evaluatethe goodness of the proposed works, usually with simulation surface flow models covering the basinwhere flood areas are located.

Increasing depth and water speed, the damageincrease. At higher speeds, the water has greatercapacity to transport objects. The damage will beconsiderable if it erodes the riverbed and will dependon the magnitude of the force of impact. It has calledvulnerability to the susceptibility of the houses weredamaged when a threat of certain intensity occurs.(For the case study, the houses and their contents orfurniture).

Vulnerability index is the proportion of the total costof the damage to houses where some flooding occursis calculated as follows:

Where:

C Total cost of damage

IV Vulnerability index (between 0 y 1)

Risk: the expected value of losses, produced by theoccurrence of a phenomenon of natural oranthropogenic origin, a particular physical or socialentity.

When vulnerability analysis is carried out in acommunity exposed to flood danger, the best way toreduce vulnerability, identifies the most vulnerablehouseholds and consequently take correctivemeasures.

It was used for location of urban areas; topographicmaps use scale 1:50,000; the location of each house isobtained by INEGI as digital information.

To estimate the vulnerability functions for each kindof housing, CENAPRED proposes a number ofconfigurations of furniture and household accordingto the Basic Guide for the State and Municipal AtlasHazard and Risk, then the vulnerability curves arepresented 5 types of houses.

Damage to the analysis, It has been identified 5 typesof houses in the urban area of Veracruz. Calculatingthe cost of content and cost furniture. The graphictypes are from I, II and III reach a depth of two metersbecause they are single-level homes, not houses typeIV and V that are houses with two or more levels.

Vulnerability and Severity

The analysis procedure is performed by the coordinatedata for each house, its respective dimension of land andwater elevation at that point for each return period,obtaining a value for each of these.

The application of computer programs was exhaustive and that there was need to simulate manypossible options to define hydraulic conditions for various probabilities of occurrence floodsoverflow rain river and basin itself

The inputs to the computer program were precipitation in each grid cell calculation every hourfor 2 specific days of a hydrological study and a mesh with specific terrain elevations for the areaof interest

A resultant product from the mathematical modeling corresponds to the envelope of depths andmaximum velocities for the entire simulation period, in other words, a map with maximumvalues, not necessarily from the same simulation time is obtained, the maximum values mayoccur at different times but the worst value considered is the maximum.

Thus, with maximum depths and certainmaximum speeds, it can be obtained maps ofseverity, where the color scale indicates in redthe worst option. Severity maps for eachreturn periods analyzed are presented in thefollowing figure.

Finally, on the study area as shown in Figure20 obtained the Expected Annual Damage.

Concepts

Hydrology. Historicflooding in the basin ofJamapa river, data aredaily rainfall of 29weather stations, all inthe state of Veracruz,daily data runoff of 2hydrometric stations arelocated in the State ofVeracruz , measuringrunoff Cotaxtla andJamapa rivers , which areshown.

In The Paso del Torostation, on September23, 1974, was recordedan average daily flow of838.8 m3/s. Anotherimportant event was onJuly 29, 1972, El Tejarstation.

Tropical cyclones thatmay have influenced the

area are shown in Figure,and the results of thesearch for hydrometeorological events inthe basin of river Jamapatoo; 3 types ofphenomena weredistinguished:

On October 3, 4 and 5,2005, came StanHurricane, on this datethe weather station30056 (El Tejar) recordedthe event as shown:

Hydrographs of Paso delToro and El Tejar are verysimilar in shape and themagnitudes were asfollows, 182 m3/s in ElTejar and 541 m3/s PasoDel Toro.

In September 17, 2010came Hurricane Karl, 3thCategory, with winds of120 km/h causingflooding in several areasof Veracruz.

Distribution of curvenumbers were used tofind the number of days,to be considered in theconstruction ofhyetographs the densityspectra, and it was

calculated with acomputer programdeveloped for thispurpose, which uses theFast Fourier Transform.

It was decided that therainy were 10 days. Thevalues corresponding tothe weather station andMata Anona and El Tejar

The valuescorresponding to theWeather Station El Tejarand Mata Anona withsimultaneity factors.

Applying the rain factors(Chen 1983) to eachstation, the ten dayshyetographs areobtained with an hourbars, then the effectivetime hyetographs of rainare shown withsimultaneity factor ofextraordinary events forEl Tejar and Mata Anona.

The basin of the Papaloapan River, occupies 41.11 % of the total land area of the state with anarea of 28.636 km2, also provides most of freshwater discharge with approximately 44.829million cubic meters per year, representing 42.28 % of the total for the state. The determininghydrological river system for this region is the Papaloapan River basin, and secondarily theActopan River, La Antigua and Jamapa.

Study area and available information

Satellite image with envelopes depthsmaximum values resulting from mathematicalmodeling in the historical event of 2010.

Satellite image with envelopes velocitiesmaximum values resulting from mathematicalmodeling in the historical event of 2010

Severity maps

IvCD