PERPUSTAKAAN UMP

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OPEN CHANNEL FLOW ANALYSIS OF DRAINS AT UNIVERSITI MALAYSIA

PAHANG CAMPUS PEKAN USING INFO WORKS CS

MOHAMAD HILMAN BIN MOHAMED SABRI

A thesis submitted in fulfillment of the

requirements for the award of the degree of

Bachelor of Civil Engineeringr

Faculty of Civil Engineering & Earth Resources

Universiti Malaysia PAHANG

JUNE 2012

ABSTRACT

Flood can be defined as an overflow of water from water body normally occurred

when the water body can no longer contain the precipitation in the area and the soil can

no longer absorb the water. This resulted in overflow and one of the causes of flood. The

study area is Universiti Malaysia Pahang (UMP) campus Pekan where it is located in an

area where flood occurrences are recorded each year with the main reason is overflow

from the Pekan River. The soil condition in the area also poses problem where it is

swampy and this type of soil have low porosity and can lead to increase in surface runoff.

The objectives of this study is to develop and validate 2-Dimensional hydrological

modeling of UMP Pekan drainage system using Infoworks CS and to determine the

capabilities of existing drain to sustained runoff at maximum level. Data are obtained

from (Jabatan Pembangunan dan Pengurusan Harta) JPPH UMP such as invert level,

platform level, and plan view of study area. The study area which is 60 hectares area in

total was divided into three zones; Zone A, Zone B and Zone C. In order to analyze the

effectiveness of the drains at UMP Pekan, two method of calculation is used which are

Rational Method for calculating the surface runoff and Manning Equation for the

calculation of drain flowrate. Infoworks CS will be used to simulate the event of 8 hour

rainfall with data obtained from MASMA with 2 ART. Water level is obtained after

simulation process is completed. Result shows Zone C experienced overflow while Zone

A drainage system experienced high water level that almost cause overflow. Only Zone B

shows properly design drainage system where water level is in the mid-section of the

drain. This result is proven both in manual calculation and software simulation.

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vi

ABSTRAK

Banjir boleh ditakrifkan sebagai limpahan air dari sungai yang biasanya berlaku

apabila sungai tidak mampu lagi menampung hujan dan tanah tidak mampu lagi

menyerap air. Kawasan kajian adalah Universiti Malaysia Pahang (UMP) kampus Pekan

di mana ia terletak di kawasan kejadian banjir direkodkan setiap tahun dengan sebab-

sebab utama adalah limpahan dari Sungai Pekan. Keadaan tanah di kawasan tersebutjuga

menimbulkan masalah di mana ia adalah berpaya dan jenis tanah mi mempunyai

keliangan rendah clan boleh membawa kepada peningkatan air larian permukaan. Objektif

kajian mi adalah untuk membangun dan mengesahkan 2-Dimensi pemodelan hidrologi

sistem perparitan UMP Pekan menggunakan Infoworks CS dan untuk menentukan

keupayaan sistem perparitan sedia ada untuk air larian berterusan pada tahap maksimum.

Data diperolehi daripada Jabatan Pembangunan dan Pengurusan Harta (JPPH) UMP

seperti terbalikkan pandangan tahap, tahap platform, dan pelan kawasan kajian. Kawasan

kajian yang ialah 60 hektar kawasan dan dibahagikan kepada tiga zon iaitu Zon A, Zon B

dan Zon C. Dalam usaha untuk menganalisis keberkesanan longkang di UMP Pekan, dua

kaedah pengiraan digunakan yang iaitu Kaedah Rasional untuk mengira air larian

permukaan dan Persamaan Manning untuk pengiraan kadar alir longkang. Infoworks CS

akan digunakan untuk mensimulasi kejadian 8 hujan jam dengan data yang diperolehi

dari MASMA dengan 2 ARI. Paras air akan diperolehi selepas proses simulasi selesai.

Keputusan menunjukkan Zon C mengalami limpahan manakala Zon A mengalami paras

air tinggi yang hampir menyebabkan air melimpah. Hanya Zon B menunjukkan reka

bentuk yang memuaskan di mana paras air di bahagian pertengahan longkang. Keputusan

mi dibuktikan dalam pengiraan manual dan simulasi perisian.

TABLE OF CONTENT

CHAPTER TITLE PAGE

DECLARATION

DEDICATION

ACKNOWLEDGEMENT iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENT vii

LIST OF TABLES xi-xii

LIST OF FIGURES xiii-xiv

LIST OF SYMBOLS xv

LIST OF APPENDICES xvi

INTRODUCTION 1

I.I. Problem statement 2

1.2. Objective 3

1.3. Scope of study 3

1.4. Location of Study 4

1.5. Significance of Study 5

2 LITERATURE REVIEW 6

2.1. Introduction 6

VII

2.2. Type of Flood ' 6

2.2.1 River Flooding 7

2.2.2 Flash Floods 7

2.2.3 Urban Flooding 8

'2.2.4 Storm Surge or tidal flooding 9

2.2.5 Floods arising due to failure of a dam 9

2.2.5.1 Banqiao dam failure 9

2.3. History 11

2.4. Hydrological cycles 12

2.5. Causes of flood 13

2.5.1 Heavy precipitation 13

2.5.2 Topography 14

2.5.3 Soil conditions and ground cover 16

2.6.. Infoworks CS 17

2.7. Flood mitigation 18

2.7.1 Reservoir planning 18

2.7.1.1 Flood Control 18

2.7.1.2 Conservation 19

2.7.2 River protection and improvement work 19

2.7.2.1 Embankment 19

2.7.2.1.1 Rock riprap 21

2.7.2.1.2 Soil-cement riprap 22

2.7.2.1.3 Articulated riprap 23

2.7.2.1.4 Concrete riprap 24

2.7.2.1.5 Vegetation 24

2.7.2.2 Bank protection 25

2.7.2.3 Channel improvement 26

2.8. Effect of flooding 26

2.9. Previous studies 27

VIII

2.10. Soil Conservation Service Model 28

2.11. Sub-catchment Area 29

2.12. Rational Method 30

2.13. Manning's Method 33

2.14. Annual Recurrence Interval 34

3 METHODOLOGY 37

3.1. Introduction 37

3.2. Flowchart of Methodology Study 38

3.3. Flowchart for Infoworks CS 39

3.4.. Study Area 41

3.5. Data Collection 44

3.6. Simulation 45

3.7. InfoworksCS 45

3.7.1 Finite Volume Formulation 46

3.7.2 Gudonov Scheme and Riemann Solvers 46

3.8. Simulation Process 47

3.8.1 Create a Master Database 47

3.8.2 Create a Catchment Group 48

3.8.3 Layer Control 48

3.8.4 Create a new node 50

3.8.5 Create a new link 53

3.8.6 Create a subcatchment 54

3.8.7 Insert data for subcatchment 56

3.8.8 Insert data for Land Use 59

3.8.9 Insert data for Rainfall Generator 61

3.8.10 Simulation 63

3.8.11 Simulation Results 65

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X

4 RESULTS

4.1. Water Depth

4.2. Water Flow

4.3. Rainfall Intensity

4.4. Simulation Results

5 CONCLUSIONS AND RECOMMENDATIONS

5.1. Conclusion

5.2. Recommendation

66

66

69

72

77

81

81

82

REFERENCES

84

Appendix A 84

Appendix B

96

Appendix C

105

LIST OF TABLES

xi

TABLE NO. TITLE

2.1 Types of subcatchments in Info Works

2.2 Rational Method Runoff Coefficients

2.3 Maiming's n values

2.4 Event ARI for various development type

4.1 Water depth for Zone A

4.2 Water depth for Zone B

4.3 Water depth for Zone C

4.4 Water flow for Zone A

4.5 Water flow for Zone B

4.6 Water flow for Zone C

4.7 Pd and I value for 30 and 60 minutes

4.8 to, td and t values for Zone A, Zone B, and Zone C

4.9 Rainfall intensity for Zone A, Zone B and Zone C

4.10 Surface runoff discharge for Zone A, Zone B and Zone C

4.11 Drainage flowrate for Zone A, Zone B and Zone C

4.12 Comparison between runoff and drain flowrate

PAGE

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32

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5.1 Recommended area and flowrate for drains 83

XII

LIST OF FIGURES

FIGURE NO. TITLE PAGE

1.1 White area on map shows UMP Pekan location 4

2.1 Banqiao dam failure 10

2.2 Hydrological cycles 14

2.3 IDF Curves for Kuala Lumpur. 16

2.4 Runoff graph. 16

2.5 Permeability and drainage characteristics of soils 17

2.6 Cross section of embankment 20

2.7 Weight of median to be used 21

2.8 Thickness of median to be used 22

2.9 Soil cement riprap specifications 23

2.10 Vegetation used as slope stabilizers 25

3.1 Flowchart for study 38

3.2 Flowchart for software processes 39

3.3 Zone A layout plan in Infoworks CS 42

3.4 Zone B layout plan in Infoworks CS 43

3.5 Zone C layout plan in Infoworks CS 44

3.6 Opening the Infoworks CS explorer 48

3.7 Inserting Layer into Infoworks 49

3.8 Selecting Layer to be inserted 50

3.9 Selecting Node to be plot 50

3.10 Inserting data for new mode 51

XIII

xiv

3.11 Insert data for node 52

3.12 Insert data for conduit 53

3.13 New subcatchment button 54

3.14 Subcatchment area shown 55

3.15 Insert subcatchment data 56

3.16 Insert data for runoff surface 57

3.17 Insert data for Land Use 57

3.18 Details for various surface type 58

3.19 Determining subcatchment parameters 60

3.20 Inserting Manning's n value 61

3.21 Insert rainfall data 62

3.22 Simulation window 64

3.23 Results output button 65

4.1 Longitudinal section of main drain at Zone A 78

4.2 Longitudinal section of main drain at Zone B 78

4.3 Longitudinal section of main drain at Zone C 79

LIST OF SYMBOLS

A - Area of the cross section (m2)

a, b, c, d - Coefficients for the IDF polynomial equations

D - Depth

I - Intensity

n - Manning's coefficient

Q - Maximum flow (m3/s)

R - Hydraulic radius (m)

S0 - Watercourse slope

t - Time

tc - Time of concentration

tp - Peak Hydrograph

V - Velocity

W - Width

Pd - Rainfall depth

FD - Area Reduction Value

to - Overland flow time

td - Drain flow time

xv

I

CHAPTER 1

INTRODUCTION

Flash flood has been the problem among developing countries. The quick pace,

uncontrolled development and lack in specifications to prevent flash flood have been the

main factors of flash flooding. As for Malaysia, the most famous case of flash flooding

happens at the capital itself, which is Kuala Lumpur. Every time when copious rain falls

for about two to three hours a few settlements and major trunk roads in the city will be

flooded (Jamaluddin, 1985). Solutions have been provided but somehow failed to

prevent the problems from happening.

Malaysia is considered as a tropical country with equatorial climate where the

weather is hot and humid throughout the year. There is no hot season and the rainfall fall

throughout the year where it is heavy and frequent. Two monsoons affect the climate of

Malaysia which is the Southwest Monsoon from late May to September, and the

Northeast Monsoon from November to March. The Northeast monsoon lasts from

November to March, as the winds blow down to the China Sea. Since this is the greatest

sweep of ocean to which the country is exposed, this season is the rainiest. It first strikes

the north and east coast of Malaysia. The east coast of Malaysia, all of Sarawak and

2

Brunei on up to Southern Sabah, and the Sandakan Residency get more than 120 inches

of rain a year. (Gould, 1969)

Most regions in Pahang receive heavy rain at this time of the year and one of the

most heavily affected is Pekan. As the new Universiti Malaysia Pahang campus at Kuala

Pekan has already been officially open to students in June 2011, a study has to be made

to determine the area is safe and have minimum risk to flash flood in the future.

1.1. Problem Statement

It is understandable that every end of the year, heavy precipitation will fall on

the east coast which resulting into flood occurrences at various locations. Flood can

cause loss of lives, loss in property, and also spread disease through its contaminated

water. Certainly the event of floods causes a lot of problems to the community living in

the affected area.

Pekan is known to be highly affected due to the Northeast monsoon season

which brings high rainfall density which leads to flooding in the area. In 2011,

Universiti Malaysia Pahang (UMP) new campus is located at Kuala Pekan, outskirt of

Pekan town, where 708 students are to be expected to stay at the given hostels. In case

of heavy rain fall, there is a chance that Kuala Pekan will be flooded thus affecting the

community in the area and also to UMP students. The learning process shall be

disturbed and students will have difficulties in coping with their study. There is also

another factor that may contribute to the flooding at the new campus which is the

construction activities done at the area, where construction site is known to produce

high quantity of runoff during raining season. Also sediments in runoff from

construction sites typically 10 to 20 times greater than agricultural land and 1000 to

2000 times greater than forest lands. Furthermore, when flood happens at the area, there

is a fair chance that the access road towards UMP Campus Pekan will be blocked as

there are only one routes connecting the new campus with Pekan town.

3

1.2. Objective

The objectives of this study are:

i. To develop and validate 2-Dimensional hydrological modeling of UMP Pekan

drainage system using Infoworks Cs.

ii. To determine the capabilities of existing drain to sustained runoff at maximum

level.

1.3. Scope of Study

This research mainly involving the effectiveness of the existing drain, by

determination of the dimensions of the drainage, which later will be use to calculate the

flowrate of the existing drain. The result then is compared with the calculated flowrate

using the software which will later determine whether the existing drain will be able to

sustain the flowrate calculated.

Obtain the data needed such as rainfall data, cross-section of the river, the

geometry of structure, perimeter watershed, water level and other data required.

Among the main activities that will be done during this study are:

1. Collecting data based on site area and rainfall data

2. Determine dimension of existing drain

3. Simulations process using software

4

1.4. Location of Study

The location of this study is located in Kuala Pahang, Pekan. This area has been

proven from time to time to be highly affected during heavy monsoon rain due to the

area incapability to flow and infiltrate the excessive water. Floods in Pekan are mainly

due to overflowing from Sungai Pahang which coincides with high tide that causes an

increase in water level at surrounding swamps. (The Borneo Post,201 1). Flooding at

Pekan has causes losses to properties and even lives. In order to minimize the impact of

flooding to the affected population, it is advisable for researchers to do more studies

regarding flood mitigation to improve the living quality in Pekan.

Sat J Ter Earth

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Figure 1.1: White area on the map shows UMP Pekan location. (Source: Google Earth)

5

Figure 1.1 shows the location of where UMP Pekan situated whicF is located

near the Pahang river. The white area on the map shows cleared area for the

construction of the campus, which can also lead to high volume of surface runoff from

construction site. In case of high tide and heavy rainfall, there is a fair chance that

together with all other factors taken into consideration, the area around the river will be

flooded like previous years.

1.5. Significance of Study

The importance of this study is to determine the capabilities of the existing drain

at UMP Pekan whether it is able to cater high volume of rainfall. Flooding will happen

when existing flowrate of drainage are lower than flowrate produced by rainfall or

runoff or other factors. All of this will be made possible using latest software to

maintain the accuracy and persistent.

It is also as a pioneer study to be done at UMP Pekan to determine the drainage

capabilities of the area and may be a tool of reference for others in pursuing study under

this field.

CHAPTER 2

LITERATURE REVIEW

2.1. Introduction

Floods are caused by weather phenomena and events that deliver more

precipitation to a drainage basin than can be readily absorbed or stored within the basin.

(USGS, 2011). Commonly it is considered to be a phenomenon associated with an

unusually high stage or flow over land or coastal area, which results in severe

detrimental effects. 'Flood control' implies all measures taken to reduce the detrimental

effects of flood.

2.2 Type of flood

Flood results from a number of causes. However, one due to heavy and

prolonged rainfall is the most frequent one. The type of flood that hit Pekan town for

almost every year is under the category of river flooding, where the whole area of East

Coast including the state of Pahang, Terengganu and Kelantan are under the effect of

Northeast monsoon season with high precipitation combine with high tide. For

Systematic studies, it is necessary to classify such flood events (Ghosh, 2006).

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2.2.1 River flooding

This is the major cause of flooding extensive areas as a result of heavy rains in

the catchment areas as well as local areas thereby increasing the river levels that can

cause major rivers to overflow their banks. The water can cover enormous areas. Even

the downstream area, which does not receive any rainfall, will be affected if the quantity

of water is enormous.

In large rivers case, the process is relatively slow. Water from rainfall will go

into the river directly, while some of them will enter the river through seepage. When

the infiltration rate of the river is low, water or runoff will be directed into other smaller

river and this entire small river will be connected to the main river. This will cause the

main river to receive excessive water quantity more than it can sustain.

Finally all the catchment area will show indicators of flooding when the water at

the main river is slowly rising. The water will eventually flow to the sea but the process

is slow and when the amount of water flowing into the river is faster than the flowing

into the river water level will rise and eventually leads to flooding.

Area affected by this type of flooding is huge, where the settlers will probably be

cut out from access road and will be isolated when flooding happens

2.2.2 Flash floods

In areas with steep slopes, heavy rain can cause a riverbed that held very little or

no water at first, to suddenly brim with fast flowing water. The rain water is collected on

the slopes, then flows downhill gathering speed and all the water comes together in the

river bed. The water level rises fast. The water flows over the river banks 'and floods the

area. Speed is the keyword where it all happens fast and rains heavily. The water flows

at high speed. Because of this speed it has the strength to carry away heavy objects as

8

can be seen in the event of Boscastle in 2004, Vaison la Romaine in 1992, and the area

of Alicante in Spain in 2007. The flood stops as suddenly as it starts.

A flash flood is a very direct response to rainfall with a very high intensity or

sudden massive melting of snow. The area covered by water in a flash flood is relatively

small compared to other types of floods. The amount of water that covers the land is

usually not very large, but is so concentrated on a small area that it can rise very high.

Because of the sudden onset and the high travelling speed of the water, flash

floods can be very dangerous. The water can transport large objects like rocks, trees and

cars.

2.2.3 Urban flooding

Local heavy rains up to 100mm or more in a day over the city and larger towns

can cause damaging and disruptive flooding due to poor or chocked drainage and rapid

runoff. The problem here is to determine the proper drainage system that will collect

water due to surface runoff and channel it to other places which can sustained the water

before the precipitation stop.

The Government of Malaysia has provided the Stormwater Management and

Road Tunnel (SMART) solution to mitigate the urban flooding at its capital, Kuala

Lumpur. The SMART system will be able to divert large volumes of flood water from

entering this critical stretch via a holding pond, bypass tunnel and storage reservoir. This

will reduce the flood water level at the Jalan Tun Perak Bridge, preventing spillover.

9

2.2.4 Storm surge or tidal flooding

This results mostly due to tropical disturbances, developing to cyclones and

crossing surrounding coastlines. Cyclone induced storm surges have devastating

consequences in coastal areas and such surge induced floods may extend many

kilometers inland (Ghosh, 2006).

A flood starts when waves move inland on an undefended coast or overtop or

breach the coastal defense works like dunes and dikes. The waves attack the shore time

and again. When it is a sandy coast, each wave in a storm will take sand away.

Eventually a dune may collapse that way.

2.2.5 Floods arising due to failure of a dam

A large number of large and small dams are constructed to store water for

various purposes. Due to poor maintenance and due to exceptionally high precipitation a

severe flood may result causing failure to the dam. This causes a surging waterfront

travelling with high velocity causing destruction of properties and loss of life.

2.2.5.1 Banqiao dam failure

In 1975, China witnessed the greatest manmade disaster that caused the death of

more number of people than in any other manmade disaster happened across the world

so far. At the beginning of August, there occurred a typhoon because of the change in

the weather pattern. When the hot, humid air of the typhoon met the cold air of the

North, series of storms and rain occurred. The first one was on August 5, followed by

the second one on August 6th and the third one on August 7th. The dam was designed to

store 300mm of water per day. During these days within 24 hours itself more than one

year's rain was poured. Banqiao and Shimantan dams were filled by August 8th and

10

were in the urge to burst. On August 8th 12:30 am, Shimantan dam collapsed followed

by the collapse of Banqiao dam by 1:00am on the same day. Totally 62 dams broke,

affecting the life of eleven million people. Even the evacuation orders failed to reach

many people because of the problem in communication caused by flood. People who

survived in this flood were trapped without food. Contaminated water affected the

health of several people. These dams were built by foreseeing the flood that may occur,

but even then, the natural calamity was of that high level and the dams failed to hold the

tempestuous water rained down. To prevent more disasters they even destroyed several

small dams so that the water would flow to the areas with less population.

These dams, which collapsed mainly, affected the local population. According to

the records nearly 26,000 people died because of flood and nearly 145,000 people died

because of famine and epidemics. Nearly 5,960,000 buildings collapsed and 11 million

residents were affected. Many were injured. This converted China into a land full of

corpses.

Figure 2.1 Banqiao dam failure

2.3 History

The word hydraulics has been derived from the Greek word Hudour, which

means "water". Hydraulics may be defined as the science that deals with the mechanical

behavior of water at rest or in motion. In some contexts it also includes the study of

other fluids. The mechanical behavior may entail computing forces and energy

associated with fluids at rest or momentum and energy of fluids in motion, or

computation of water surface elevation in channels and flood plains, or calculation of

discharge, velocity, and fluid potential, and sediment and pollutant transport in

hydraulic conduits. The science of fluids at rest is called hydrostatics, and the science of

moving fluids is called hydrodynamics (Cruise, Sherif, Singh, 2007).

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12

2.4 Hydrological cycles

11

Sto

-

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,--.-------- p V *** .

moisture over ir ice a^Fs3nonw

condensation ***.I• \ V

Pr ecipitation

on land

e 66 Evaporation from land Precipitation na \AAÔ .

EvaaotrEvapotranspiration00ocean

66t

- FreshwaterS ) (y.lpOrMiOfl storage

Infanat,on hjij._" 1Evaporation from ocean

Surae outflow

Groundwater flowGroundwater outflow_

storage

Figure 2.2: Hydrological cycles (Source: http://geofreekz.wordpress.com/the-

hydrosphere)

Water is a renewable resource and follows the hydrological cycle, as shown in

figure 2. The hydrological cycle is an endless circulation and has neither beginning nor

end. It is a natural machine, a constantly running distillation and pumping system. The

sun supplies heat energy which, together with the force of gravity, keeps the water

moving; from the atmosphere to the earth as condensation and precipitation; from the

earth to the atmosphere as evaporation and transpiration, to the oceans as stream flow,

and within the earth as stream flow and groundwater movement; and from the oceans to

the atmosphere as evaporation (Singh, 1992).