Flash Flood Hazard Mapping in the Municipality of Tumauini using GIS tool

Chapter I

Flood is the most frequent and the most devastating water-related disaster in the world. It
is a natural phenomenon. It causes tremendous havoc to human life and property. Due to
torrential rains caused by a typhoon, a flood occurs in a low-lying area of Tumauini particularly
in the north and south part of the municipality.

During a flood, the water in the Cagayan River rises very high. It sweeps away
everything such as crops and houses are damaged, many people are rendered homeless. Their
belongings are washed away. Many individuals and animals are drowned. The LGU of
Tumauini, precisely the NDRRMC they identify flood-prone areas through the use of flood
hazard mapping, it is one of the solutions to prevent flood losses to human lives and properties in
the municipality.

This proposal discusses the Flash Flood Hazard Mapping Information System consists of
the gathering of household location to identify flood-prone house within an area to assess their
vulnerability. It also includes the group of homes' profile such as household type, socio-
economic status, family composition and their Educational Structure. Data gathered will be
treated to identify and represent the density of household located within flood-susceptible areas
as well as to map the density of houses' regarding household type, socio-economic status, family
composition and their Educational Structure through the use of Google Earth and ARC
Geographic Information System for graphical data representation.
Statement of the Problem
This research focuses in the development of Household Flood Hazard Mapping
Information System that aims to answer the following questions:
1. What are the problems encountered with the existing Flood Hazard Mapping in terms
of the following:
a. Availability;
b. Usability;
c. Efficiency
2. What are the needed features of the proposed Flood Hazard Mapping based on the
problems encountered in the existing technologies?
3. What are the Flood Hazard Information of the Local Government Unit of Tumauini,
Isabela using the Flood Hazard Mapping Information System in terms of the
following:
a. Household Location;
b. Household Profile;
c. Household Flood Susceptibility.

Objectives:
This study aims to develop a Flash Flood Hazard Mapping specifically to:

 To determine the problems encountered with the present technologies for Flash Flood
Hazard Mapping.
a. Availability;
b. Usability;
c. Efficiency

 To determine the needed features of the proposed Flood Hazard Mapping based on the
problems encountered of the present technologies.
 To inform the public and relevant authorities about the flood risk and how to deal it.
Scope and Delimitation

This project focuses only on the development of a Flash Flood Hazard Mapping
Information System to identify and quantify those houses which are at risk of flooding and to
create a household map of every barangay within the municipality. Records of floods of
Tumauini, Isabela were collected from local government offices such as the NDRRMC. Maps
that concern this calamity in the scope of limitation were searched through the Internet or LGU
of Tumauini, modified and recreated to be easily understood and to provide a clearer
presentation of the areas.

Significance of the Study

This study entitled "Flash Flood Hazard Mapping System" act as an information system
to give awareness to the people. It will help to identify the range of urgency and clean up
operations.
It will also determine those areas which are at risk of flooding. For instance, those areas
which are prone to flooding that need evacuation and signposted, so people of the community are
made aware in advance of the emergency.
 Chapter II
Review Related Literature

According to Eric KwabenaForkuo describes "Flood Hazard Mapping using Aster Image
Data with GIS" on the prerequisite of a well-organized and fruitful methodology for formulating
flood vulnerability charts in Ghana, especially in individuals region which is suspected by the
flood. By the amalgamation of GIS and ASTER imaginings in a grouping of DEM's in
describing flood vulnerability level in each district of the study area. An additive model was used
in combination with the above model to produce a composite flood hazard index. Different
parameters were examined such as resident's density, number of settlements in each district, area
of civilized ground in developing this model. Moreover, extreme flood-prone zones were also
plotted using high-resolution DEM, and the areas were taken out by applying spatial study on
GIS model.

According to (Karamat Ali, Roshan M Bajracharya1, Hriday Lal Koirala, Farida Begum,
2016) in their article "A Review of Flood Risk Assessment." Flood is the most common hazards
in the world it causes loss of lives, livelihood and property destruction. The incident of floods in
mountainous regions are now more common related to the past, and in future, it seems more
frequent due global warming. Community-based flood information systems can go a long way in
helping flood management agencies, rural communities, to be ready for flash floods.
Advancement in GIS, hydraulic modeling technology and remote sensing extensively used in
formulating models used for flood hazard calculation and risk analysis.

According to the article "Flash Flood Hazard Mapping Using Satellite Images and GIS
Tools" of Ismail Elkhrachy. Flash flood is a natural hazard that poses a risk to both populations
and structures within the affected areas. Several factors influence the amount of runoff which
helps determine the intensity of flooding. Therefore, physical characteristics such as impervious
surfaces, the hydraulic rating of soil, and flow accumulation of water were combined with
demographic characteristics to create a composite flood hazard index. ArcMap is used to extract
the drainage network based on DEM for the study area. Two DEMs (SPOT 5 and SRTM) data
have been used. Accuracy assessment of used DEMs has been investigated by using checkpoints,
GPS observations collect their elevations. SPOT data are more accurate and dense flow network
for the study area. AHP is used to determine relative impact weight of flood causative factors to
get a composite flood hazard index map. All used data are finally integrated to prepare a final
flood hazard map for the study area.

According to (Arbindra Shrestha, Mukesh Bhattarai, Sunil Thapa, 2011) in their article.
Floods repeatedly occur in Nepal and cause tremendous losses regarding property and life,
particularly in the lowland areas of the country. Hence, they constitute a significant hazard. They
integrate flood simulation model, remotely sensed data with topographic and socio-economic
information in a GIS environment for flood risk mapping in the floodplain of Kankai River in
Nepal. The results obtained from GIS modeling were verified with a social approach to
vulnerability assessment. Flood risk level and warning level was identified by immediate
discharge data and gauge height. 3.7m marked as warning level and at 4.2m is marked as danger
level. The result shows that the agriculture system of the study area is in more vulnerable
position. The hazard-prone area will be considerably increased from 25 year-return period flood
to 50 year-return period flood.

According to (Vahdettin Demir and Ozgur Kisi,2016), Flood hazard mapping of Mert
River Basin, Samsun, Turkey, was investigated using GIS and HEC-RAS. Human life losses
and a significant amount of property damages were experienced in 2012 flood. The preparation
of flood risk maps includes the following: a) simulation of wave lows of different return periods
using a hydraulic model (HEC-RAS), b) digitization of topographical data and development of
digital elevation model using ArcGIS, and (3) preparation of flood risk maps by integrating the
results of (a) and (b)
 Chapter III
Technical Background

This chapter discusses the technicality of the project that describes the type of the project
to be developed and its functionality. It also represents the type of application in the development
of the project.

The "Flood Hazard Mapping" is an essential component of land use planning in flood-
prone areas. It creates easily-read, rapidly-accessible charts and maps which facilitate the
identification of sectors that risk of flood and also helps prioritize mitigation and response
efforts.

A "Geographic Information Systems" is a computer-based tool that analyzes stores,

manipulates and visualizes geographic information, usually in a map. It will used in formulating
models used for flood hazard calculation and risk analysis.

The Google Map APIs will be used to view the real scenario of every location of houses
and its susceptibility. It will also be used to draw a map of every municipality.

The Hypertext Pre-processor (PHP) it is a server-side scripting language designed

primarily for web development but also used as a general-purpose programming language. The
system worked on a system operated under Windows 7, 8, 10 and 10.1. This operating system
will allow the application to run properly.

MySQL is a Relational Database Management System (RDBMS) that uses Structured

Query Language (SQL). It was used as to manage the database of the application system.

The NAVICAT Premium was also used to connect to MySQL database to allow data
migration between the databases. This will provide a function for visual query-builder, SSH and
HTTP tunneling, data and structure migration and synchronization, import and export and
backup of data, report builder and task scheduling and wizards tool.
 The functionality of this information system will be beneficial to the department to
identify those areas at risk of flooding to help inform emergency responses. The sectors that
require evacuation can be determined; the removal ways can be quickly planned, and provide
advance awareness to the families concern. It can also be an advantage to the department in
planning a more efficient emergency response.

The scope of this section is the discussion of the technology used on how the proposed
system will work and the necessary details or the requirement for running the system. The
hardware specification is composed of Motherboard (any); CPU (Corei3); RAM (4mb); Power
supply (any); Hard disk drive (500gb); Keyboard (any); Uninterrupted Power Supply (UPS)
(any); Mouse (any)
 CHAPTER IV
Methodology

The study is based on a descriptive method. Descriptive method of research is a fact-

finding study with the adequate and accurate interpretation of the findings.
In the beginning, the waterfall model will be used by the researcher; a typical software
development life cycle model (SDLC) used in software development.

Respondents of the Study

This research proposal entitled, “Flash Flood Hazard Mapping” have the following

respondents:

a. LGU Tumauini

b. NDRRMC Officers and Staff

c. Citizen of Tumauini

Data Gathering Procedures

The following steps were involved in the gathering of data for the study.
a. Preparation of the structured questionnaire for the intended respondents.
b. The floating, administering and gathering of the questionnaire personally by the
researchers.
c. Supplementing the data gathered to check or to verify the data obtained.

Data Gathering Instruments

The following methods were used to obtain necessary data required in the study.
a. Interview – the researchers conducted an actual interview to the respondents to ensure
accuracy of recording the data.
b. Observation – through observation, essential data were obtained on how the flood
hazard map works.
c. Internet Research – one of the most powerful instruments that the researcher used.
Through browsing and surfing, the researchers gained more and more knowledge and
information for the implementation of data to the studies.
d. Questionnaires – through floating questionnaires, the researchers can get more
information regarding the existing system and its problem.