Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect ScienceDirect AvailableProcedia online Engineering at www.sciencedirect.com 00 (2017) 000–000 Procedia Engineering 00 (2017) 000–000 www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia ScienceDirect Procedia Engineering 212 (2018) 69–76

7th International Conference on Building Resilience; Using scientific knowledge to inform policy 7thand International practice in disaster Conference risk reduction,on Building ICBR2017, Resilience; 27 Using – 29 Novemberscientific knowledge 2017, Bangkok, to inform Thailand policy and practice in disaster risk reduction, ICBR2017, 27 – 29 November 2017, Bangkok, Thailand Flood Hazard Zoning of City: Towards the Development of Flood Hazard Zoning of Tarlac City: Towards the Development of Flood Overlay Zones and Provision Flood Overlay Zones and Provision Dr. Murphy P. Mohammed* Dr. Murphy P. Mohammed* College of Engineering, College of Engineering,Tarlac City, TarlacPhilippines State University Tarlac City,

Abstract Abstract The province of Tarlac in the Philippines is one of the commonly flooded areas due to its geographical characteristics.The province The of provinceTarlac in is the surrounded Philippines by i s highone ofmountains the commonly along itsflooded eastern areas and due western to its outskirtsgeographical but characteristics.predominantly theThe province province is a isvast surrounded flat area. by high mountains along its eastern and western outskirts but predominantlyThe present the study province focuses is a on vast the flat developme area. nt of flood model for the urban areas of Tarlac City wherein a flood overlayThe zonepresent is studydeveloped focuses based on the on developme the floodnt hazardof flood model. model Specifically,for the urban areasthe study of Tarlac focuses City on wherein attaining a flood the overlayfollowing zone objectives: is developed to develop based a floodon the inundation flood hazard model; model. to determine Specifically, the haz theards study on the focuses existing on land attaining use as wellthe followingas determine objectives: the susceptibility to develop to a floodflood hazardinundation and determinemodel; to determinethe risks on the the haz urbanards onbarangays; the existing and land to look use intoas well the asimplications determine ofthe land susceptibility use policies to towards flood hazard risk management. and determine the risks on the urban barangays; and to look into the implicationsHistorical, of landanalytical use policies and qualitative towards riskmet hodsmanagement. were employed to attain the objectives of the study. Stakeholders in theH istorical,City Disaster analytical Risk and Reduction qualitative and met Managementhods were employedCouncil (CDRRMC) to attain the wereobjectives involved of the in study.the formulation Stakeholders of inpolicies the City and Disaster strategies Risk which Reduction may lessen and the Management flood hazards Council as well (CDRRMC) as the risks weretowards involved the urban in the communities. formulation The of policiesoutcome and of thestrategies workshop which will may be incorporated lessen the flood to the hazards updated as comprehensive well as the risks land towards use plan the (CLUP) urban communities. of Tarlac City. The outcome of the workshop will be incorporated to the updated comprehensive land use plan (CLUP) of Tarlac City. © 2017 The Authors. Published by Elsevier Ltd. © 2018 The Authors. Published by Elsevier Ltd. ©Peer 201-review7 The Authors.under responsibility Published by of Elsevier the scientific Ltd. committee of the 7th International Conference on Building Resilience. Peer-review under responsibility of the scientific committee of the 7th International Conference on Building Resilience. Peer-review under responsibility of the scientific committee of the 7th International Conference on Building Resilience. Keywords: Flood Hazard Zoning, Flood Overlay Zones, Risk Management Keywords: Flood Hazard Zoning, Flood Overlay Zones, Risk Management

*Corresonding author. Tel.: +639228142577 * CorresondingEmail address: author.:[email protected] Tel.: +639228142577 Email address: :[email protected]

1877-7058 © 2017 The Authors. Published by Elsevier Ltd. 1877Peer--review7058 © under 2017 responsibilityThe Authors. Publishedof the scientific by Elsevier committee Ltd. of the 7th International Conference on Building Resilience. Peer-review under responsibility of the scientific committee of the 7th International Conference on Building Resilience.

1877-7058 © 2018 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the scientific committee of the 7th International Conference on Building Resilience 10.1016/j.proeng.2018.01.010

10.1016/j.proeng.2018.01.010 1877-7058 2 M.P.Mohammed/ Procedia Engineering 00 (2017) 000–000

70 Murphy P. Mohammed / Procedia Engineering 212 (2018) 69–76 M.P.Mohammed/ Procedia Engineering 00 (2017) 000–000 3

1. Introduction 1. To develop a flood inundation model. 2. To determine the flood hazard and susceptibility on the existing land use and to determine the risks on the The Philippines is one of the countries around the world oftentimes experiencing disasters such as earthquake, urban barangays. volcanic eruption, typhoon, tsunami, drought, as well as flooding among others. Flooding is the most frequently 3. To look into the implications of land use policies towards risk management. experienced phenomenon in the Philippines due to the monsoon rains and typhoons experienced by the country. On average, the country experiences about 20 typhoons (more or less) per year. On the other hand, monsoon rain affects 3. Research Methodology the weather system of the country for about six months or half of the year. This causes flooding in many parts of the country. Excessive rainfall runoff can cause urban flooding as well as breach on river dikes or levees which likewise can The study involved historical, analytical and qualitative methods to obtain its objectives. As regards historical cause flooding to low lying towns and villages. Damage to property, agriculture, as well as loss of lives may be method, rainfall data were gathered from the Philippine Atmospheric, Geophysical and Astronomical Services encountered during floods. The Philippines experienced several disasters related to flooding which caused many Administration (PAG-ASA). Rainfall data from the synoptic station in Tarlac City were acquired from the Agno deaths and damage to property in the last decade. River Flood Forecasting and Warning Center (ARFFWC) of PAG-ASA. The province of Tarlac in the Philippines is one of the commonly flooded areas due to its geographical Analytical method considered in the study was 2D flood hazard modeling. The use of geographic information characteristics. The province is surrounded by high mountains along its eastern outskirt (part of and system (ArcGIS version 10.2), LIDAR/SAR DEM data, raster and vector images of the study area, rainfall data, and provinces) and western outskirt (province of ) but predominantly the province is a vast flat area. FLO-2D Basic software were utilized in the study. The province of Tarlac has 17 municipalities and one city. Qualitative method involved in the study was the conduct of workshops with the stakeholders of Tarlac City. The population of Tarlac City is 342,493, based on the 2015 National Statistical Coordination Board (NSCB) The stakeholders were identified by the Tarlac City government whom it wished to involve in the aforesaid data [1]. There are 141,439 people residing in the urban barangays whereas in the rural barangays there are 201,054 workshop. The stakeholders were involved in the formulation of policies and strategies which may lessen the flood residents. hazards and risks towards the urban communities based on the results of the developed flood hazard modelling. According to the City Disaster Risk Reduction and Management Office (CDRRMO), several barangays in the Officials present during the workshop were from the: City Planning and Development Office; City Environment and city were identified as flood prone, heavily flooded areas, and/or isolated during heavy rains. Based on the record of Natural Resources Office; City Social Welfare and Development; City Engineering Office; City Disaster Risk the CDRRMO, 17 out of the 76 barangays or 22.37 percent are prone to flooding. Reduction and Management Office; and representative from the City Administrator’s Office. The Comprehensive Land Use Plan (CLUP) of Tarlac City was approved in 2003 and to be adapted up to 2010. In 2014, the Housing and Land Use Regulatory Board (HLURB) released a new guide to comprehensive land use 4. Results and Discussions plan preparation. The following year, Tarlac City initiated to update the CLUP. Unfortunately, several years passed but the new CLUP of Tarlac City is yet to be approved. 4.1. Flood Inundation Model Section 13.2 of the 2014 CLUP Guidebook of the HLURB states that flood overlay zone regulations are applied in areas that have been determined in the CLUP as flood-prone. The objective of the flood overlay zone is to protect The current study developed several flood hazard models based on the 2-year, 5-year, 10-year, 15-year, 25-year, lives and properties from the harmful effects of flood [2]. 50-year, and 100-year extreme rainfall data gathered from the Agno River Flood Forecasting and Warning Center Flood risk is a function of two arguments: hazard probability and vulnerability. In other words, risk is a (ARFFWC) of the Philippine Atmospheric Geophysical and Astronomical Services Administration (PAGASA). The mathematical expectation of vulnerability (consequences) function. Flood probabilities are determined in order to computed extreme rainfall value was based on the 9 years of gathered rainfall data. In Table 1, the computed produce flood hazard maps [3]. Flood risk may be treated as a set of triplets: a set of scenarios, scenario extreme values of precipitation are presented. probabilities, and consequences per scenario [4]. Flood risk assessment consists of four steps: (i) hazard assessment; The FLO2D Basic software was used in the model development. Inputs used in the model were the digital (ii) exposure assessment; (iii) vulnerability assessment; and (iv) risk assessment [5]. Flood hazard risk is usually elevation model (DEM), soil classification, rainfall data, and different shapefiles. The developed inundation model measured by the probability that a flood will occur [6]. only covered the urban barangays of Tarlac City wherein 41 percent of the population or about 141,439 of the Water level can represent flood risk, although total flood volume or flood velocity can likewise be used to populace reside. The central business district, essential facilities, as well as industrial zones are all situated in the measure flood risk [7]. Flood hazard risk assessment is important in ensuring healthy and sustainable development study area. The study area is approximately 52 square kilometers. of human society [8]. Flood may result to the destruction of natural environment and natural resources as well as to the dispersal of epidemic diseases and destruction of habitats [9]. Table 1. Computed Extreme Values (in mm) of Precipitation Good planning is the key to minimizing the long-term risks of damage from flooding. The principle is simple – Return Precipitation plan and develop properties, buildings and structures so that they are safe from flooding from the outset without PeriodPeriod 10 20 30 1 2 3 6 12 24 compromising the safety of other properties. Prevention is far cheaper than the cure [10]. (yrs) mins mins mins hr hrs hrs hrs hrs hrs 2 17.1 25.0 32.1 41.7 50.6 55.8 67.3 82.0 98.6 2. Objective of the Study 5 21.9 32.0 41.1 53.4 67.5 75.4 89.9 114.9 138.5 10 25.1 36.7 47.1 61.1 78.8 88.3 104.9 136.6 165.0 15 26.9 39.3 50.4 65.5 85.1 95.6 113.3 148.9 179.9 The present study focuses on the development of flood model for the urban areas or urban barangays of Tarlac 25 29.1 42.5 54.6 70.9 93.0 104.7 123.8 164.2 198.5 City wherein a flood overlay zone will then be developed based on the flood hazard model. Specifically, the study 50 32.0 46.9 60.2 78.2 103.6 116.8 137.9 184.6 223.3 tries to attain the following objectives. 100 35.0 51.2 65.7 85.4 114.0 128.9 151.8 204.8 247.9

Based on the soil type classification map acquired from the Provincial Government of Tarlac, the soil type of the study area is classified as Zaragosa Clay. The specified soil classification became the basis of the researcher as to the input parameter for the model using the Green and Ampt infiltration method. The Manning’s Roughness Download English Version: https://daneshyari.com/en/article/7225841

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