MODELING OPERATION OF FLOOD DIVERSION BARRAGE IN CONJUNCTION WITH KUCHING BARRAGE FOR FLOOD
MITIGATION
Jong Swee Lek
Final year project
Bachelor of Engineering with Honours (Civil Engineering)
2010
Faculty of Engineering
UNIVERSITI MALAYSIA SARAWAK
BORANG PENGESAHAN STATUS TESIS
Judul: MODELING OPERATION OF FLOOD DIVERSION BARRAGE
IN CONJUNCTION WITH KUCHING BARRAGE FOR FLOOD MITIGATION
SESI PENGAJIAN: 2006 – 2010
Saya JONG SWEE LEK (HURUF BESAR)
mengaku membenarkan tesis * ini disimpan di Pusat Khidmat Maklumat Akademik, Universiti Malaysia Sarawak dengan syarat-syarat kegunaan seperti berikut:
1. Tesis adalah hakmilik Universiti Malaysia Sarawak.
2. Pusat Khidmat Maklumat Akademik, Universiti Malaysia Sarawak dibenarkan membuat salinan untuk tujuan pengajian sahaja.
3. Membuat pendigitan untuk membangunkan Pangkalan Data Kandungan Tempatan.
4. Pusat Khidmat Maklumat Akademik, Universiti Malaysia Sarawak dibenarkan membuat salinan tesis ini sebagai bahan pertukaran antara institusi pengajian tinggi.
5. ** Sila tandakan ( ) di kotak yang berkenaan
SULIT (Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia seperti yang termaktub di dalam AKTA RAHSIA RASMI 1972).
TERHAD (Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi/
badan di mana penyelidikan dijalankan).
TIDAK TERHAD
Disahkan oleh
(TANDATANGAN PENULIS) (TANDATANGAN PENYELIA)
Alamat tetap: 303, LORONG 7F , JALAN SEMABA , 93250 KUCHING
SARAWAK PROFESSOR FREDERIK J. PUTUHENA
(Nama Penyelia)
Tarikh: 30 April 2010 Tarikh: 30 April 2010
CATATAN * Tesis dimaksudkan sebagai tesis bagi Ijazah Doktor Falsafah, Sarjana dan Sarjana Muda.
** Jika tesis ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/organisasi berkenaan dengan menyatakan sekali sebab dan tempoh tesis ini perlu dikelaskan sebagai SULIT dan TERHAD.
The Following Final Year Project:
Title : MODELING OPERATION OF FLOOD DIVERSION
BARRAGE IN CONJUNCTION WITH KUCHING BARRAGE FOR FLOOD MITIGATION
Author : JONG SWEE LEK
Matric number : 16396
has been read and certified by:
_________________________ ______________
PROFESSOR FREDERIK J. PUTUHENA Date
(Supervisor)
MODELING OPERATION OF FLOOD DIVERSION BARRAGE IN CONJUNCTION WITH KUCHING BARRAGE FOR FLOOD
MITIGATION
JONG SWEE LEK
This subject is submitted in partial fulfillment of
the requirements for the Degree of Bachelor of Engineering with Honours (Civil Engineering) 2010
i
Dedicate To My Beloved Family And Friends
ii
ACKNOWLEDGEMENT
First of all I would like to express my highest gratitude to my honoured project supervisor, Prof. Dr. F.J. Putuhena for his advice and guidance throughout my entire project writing period. Secondly I would like to thank Mr. Darrien Mah Yau Seng for helping me throughout doing the modeling and simulation. Without, your professional help, it would be impossible for me to complete this project on time. Thank you once again.
My gratitude also goes to Norliza Binti Aslan Joe, the previous research of the Sarawak River which allowed me to continue my own thesis research by using her research model.
Thank for my family support throughout the whole research for always being there for me when I needed you most. Your love and support has given me the inner strength to go the extra mile to complete my studies. And lastly not forgetting to Nur Ain, Suhaila and ryan hardin who works with me through this studies and thanks those involved directly or indirectly in the completion of this thesis.
iii
ABSTRAK
Sejak 50 tahun yang lepas, Sungai Sarawak telah mengalami beberapa bencana banjir bermula dengan yang berlaku pada tahun 1963, diikuti pada Februari 2003, seterusnya pada Januari 2004 dan yang terbaru pada bulan Januari 2009. Selepas kejadian tersebut, Satu terusan banjir buatan sepanjang 8 km dengan kelebaran dasar 250 m bermula dari Kampong Paroh ke Batang Salak telah dicadangkan untuk menghala keluar air dari Sungai Sarawak daripada mengalir ke kawasan Bandar Raya Kuching.
Tujuan utama kajian ini dijalankan ialah untuk mengkaji semula masalah di kawasan- kawasan kerap banjir di sekitar Sungai Sarawak dan untuk menjalankan analisis tentang operasi terusan banjir buatan yang bakal dibina dengan benteng hilir kuching semasa musim banjir. Model Sungai Sarawak telah dihasilkan menggunakan permodelan hidrodinamik 1-Dimensi dengan mengaplikasikan dua perisian kejuruteraan iaitu InfoWorks River Simulation (RS) dan juga GIS menggunakan data daripada banjir yang
berlaku pada Januari 2009 bagi mendapatkan profil banjir di sepanjang Sungai Sarawak.
Hasil simulasi menunjukkan bahawa terusan banjir tersebut telah mengurangkan kadar banjir di Sungai Sarawak. Keputusan yang diambil dari kawasan Kuala Maong menunjukkan pengurangan paras air sebanyak 6.5%. Dengan ini, operasi terusan banjir buatan yang bakal dibina dengan benteng hilir kuching berupaya mengurangkan kejadian banjir di sungai Sarawak.
iv
ABSTRACT
Sarawak River had experienced several terrible flood events over the past 50 years, with the worst being in 1963, followed by February 2003, January 2004 and January 2009 flood. After the incident, a flood bypass channel proposed as a flood mitigation measure to reduce the flooding condition along the Sarawak River. The proposed flood bypass channel is 8 km long with 250 m base width man-made channel starting from Kampong Paroh to divert flood waters from Sarawak River away from Kuching city to Batang Salak. The main purpose of this project was to review the flooding problems in flood-prone areas of Sarawak River basin and analysis the operation flood diversion barrage in conjunction with the downstream barrage during the king tidal event. Sarawak River and its floodplains were modeled using one-dimensional hydrodynamic modeling approach, by develop the Wallingford Software model - InfoWorks River Simulation (RS), with the GIS applications, to obtain the flood hydrographs of the river and its floodplains in extreme flooding condition of flood event of 2009. The simulated results of January 2009 flood obtained showed that the operation of flood diversion barrage and downstream barrage had been diverting significant portion of flood waters from Sarawak River. Results taken from Kuala Maong showed a total average water level reduction of 6.5%. It is showed that the operation of flood diversion change in conjunction with downstream barrage be able to reduce the flood condition of Sarawak river.
v
TABLE OF CONTENTS
Content Page
Acknowledgement ii
Abstrak iii
Abstract iv
List of Tables ix
List of Figures x
List of Nomenclature xiii
List of Abbreviation xiv
CHAPTER 1: INTRODUCTION 1
1.1 Historical background 1
1.1.1 Sarawak River 1
1.1.2 Flood problem in Sarawak River 2
1.2 Introduction of Diversion channel 4
1.3 Objectives 5
1.4 Scope of work 5
vi
CHAPTER 2: LITERATURE REVIEW 6
2.1 Flooding 6
2.1.1 Types of flooding 7
2.1.2 Flood mitigation 10
2.2 Flood By-pass channel 11
2.2.1 Hydraulic effects 12
2.2.2 Flood Bypass Channel Kuching 13
2.2.3 Yolo Bypass Channel 15
2.3 Barrages 17
2.3.1 Sarawak River barrage 18
2.4 Application of Inforworks RS Software 19
2.4.1 Data and Model management functionality 20
2.4.2 Saint-Venant equations 21
2.4.3 The continuity equation 21
2.4.4 The energy equation 24
2.4.5 Roughness Coefficient 26
2.5 Geographical Information Systems (GIS) 29
vii
CHAPTER 3: METHODOLOGY 31
3.1 Introduction 31
3.2 Flow chart study 32
3.2.1 Collecting the Data from DID 34
3.2.2 Sarawak River and Maong River model development 34
3.2.3 Export data to infoworks RS software 35
3.2.3 Boundary condition 35
3.2.5 Calibration and Validation Event 36
3.2.6 By-pass channel Scenario and the performance Evaluation 36 CHAPTER 4: RESULTS, ANALYSIS AND DISCUSSION 37 4.1 Hydraulics simulation results 37
4.1.1 Hydraulic model without flood bypass channel 39 4.1.2 Hydraulic model with flood bypass channel 41
4.2 Water level at river section 44 4.2.1 Water level without flood bypass channel 45 4.2.2 Water level with flood bypass channel 46 4.3 Water level data comparison 48
4.4 Discussion 49
viii
CHAPTER 5: CONCLUSION AND RECOMMENDATIONS 50
5.1 Conclusions 50
5.2 Recommendations 51
APPENDIX 52
REFERENCES 54
ix List of Tables
Table Page
2.1 The function of Infoworks 20 4.1 Five days gate operation of flood diversion barrage 43 4.2 Maximum water level for each operation 46
x
List of Figures
Figures Page
1.1 Sungai Sarawak river basin 3
1.2 Kuching barrage and ship lock 3
1.3 Maong river basin 4
2.1 Layout of the Sungai Sarawak Flood Bypass Channel (DID) 14 2.2 Location of the projects (DID) 14
2.3 Yolo Bypass 16
2.4 Arrangement of Sarawak Barrage (side view) 18 2.5 Arrangement of Sarawak Barrage (cross section view) 18
2.6 Scheme for the continuity equation 22
2.7 Scheme for the energy equation in a cross section 24
2.8 GIS layer 30
3.1 Flow chart in River Modeling 33
4.1 Location of Buan Didi, Kg Git and Downstream Barrage 38 4.2 Maximum flood extents without flood bypass channel 40 4.3 Enlarged view of maximum flood extent at S46 40 4.4 Maximum flood extents with flood bypass channel 41 4.5 Enlarged view of maximum flood extent at S46 42 4.6 Location of cross sections S46 Kuala maong 44
xi
4.7 Floods without Flood Bypass Channel- Sarawak River
(S46 – Kuala Maong) Cross Section 45
4.8 Floods with Flood Bypass Channel of operation D- Sarawak River (S46 – Kuala Maong) Cross Section 47 4.9 Water level comparison graph for Kuala Maong river section 48
xii
LIST OF NOMENCLATURE
A - cross sectional flow area U - Average velocity of water x - distance along channel B - water surface width h - depth of water t - time
St - friction slope
Se - channel bed slope
Se - friction slope/energy slope Sr - bed slope
g - gravitational acceleration km - kilometer
mm - milimetre
m - metre
n - Manning's roughness coefficient P - Wetted perimeter
Q - Flow
q - Lateral inflow per unit length of channel R - Hydraulic radius
Se - Friction slope Sr - Channel bed slope
t - Time
xiii
H - water surface elevation above datum (m) ß - momentum correction coefficient
g - gravitational acceleration (m/s2)
- angle of inflow K - channel conveyance K2 - A2 R4/3 / n2
xiv
LIST OF ABBREVIATION
DID - Department of Drainage and Irrigation DTM - Digital terrain Model
ESRI - Envinronmental Systems Research Institute LSD - Land Survey Datum
GIS - Geographical information system RS - River Simulation
TIN - Triangulated Irregular Network
1
CHAPTER 1
INTRODUCTION
1.1 Historical background
1.1.1 Sarawak River
Sarawak River is the important river in Kuching which play roles such as it is important source of water and transportation for the inhabitants in southwestern Sarawak. Total Length of Sarawak River is 120km long and the Sarawak River Basin Area is 2459 km².and its exits are toward the South China Sea. According to the Sarawak topography map, there were two major tributaries in Sarawak River which are Sarawak Kanan River and Sarawak Kiri River. From the topography, the two tributaries meet at the Batu Kitang area. Sarawak River (Sg. Sarawak) flows through the City of Kuching dividing it approximately into two equal halves (figure 1.1).
Kuching City is located in tidal influence zone with a tidal range of approximately 6 meters. Sarawak river average annual rainfall of 3830mm and the total annual surface water runoff is about 306 billion cubic metres (m3).
2 1.1.2 Flood problem in Sarawak River
The topography of the Sarawak state is the main cause of flood problems occurred in Sarawak River. The topography of Sarawak is the high grounds in the interior along a northest-southwest direction bordering with Kalimantan Indonesia.
The river courses are relatively short with steep gradients in upper stretches and comparatively flat and meandering stretches in the lower reaches. Flood flows are passing in upper reaches but increase in duration and intensity towards the plain area.
Bulk of population is concentrated in towns and villages in river valleys and coastal plains and hence prone to flood damages. Thus, the flooding phenomena is typically occurs in town area which is coastal plain.
The construction of Sarawak River Barrage in 1998(figure 1.2), the most significant flood events in the history of Sarawak occurred in January and February 1963. During this period, the state experienced an abnormal heavy rainfall, recorded as 2500mm for the two months. Spring tides from the sea coincided with heavy precipitation from the upstream catchments. Therefore the excess of runoff had given rise to the water levels and causing the low-lying areas to be flooded, as high as 7 meters. Even after the barrage is in operation, hitherto major flood events still occur although in a minor magnitude. Examples are the flood events in February 2003 and January 2004 which saw a rise in the water levels, up to 3 meters. These issues still affects citizens who stay around the floodplain area such as Maong River where still facing flood during the wet season.
3
Figure1.1: Sungai Sarawak river basin (http://maps.google.com)
Figure 1.2: Kuching barrage and ship lock (http://www.cmsb.com.my)
Kuching city
Tributary Sungai
Sarawak Kanan
Tributary Sungai Sarawak Kiri Sungai Sarawak
Kuching barrage
4 1.2 Introduction of Diversion Channel
Diversion channels are constructed to divert waters from the main channel for purposes such as flood control, municipal and water supply. A type of diversion channel used for flood control is a flood by pass channel or called floodway. It is a separate channel into which flood waters are directly to lessen the impact of flooding on the main river system. The control structures maybe located at the head of the diversion channel to divert flows during period of high water and return flows during low water. Diversion channels are often used in urban areas where it is not possible to widen the existing channel due to development. Diversion channels may be used to provide a means of diverting flood water across the neck of a meander or series of meanders (Acheson, 1968).
Major design consideration for diversion channels include:
(a) Determinacy if the channel should convey partial or all flows
(b) Design of appropriate controls and sizing of the channel to convey the design discharge.
(c) Design to reduce maintenance
5 1.3 Objectives
In order to prevent the flooding problem in Sarawak river area, the main objectives is to studies the flood mitigation option by using the by-pass channel during the high tidal event. The operation of this by-pass channel with the Kuching barrage will definitely affect the flood phenomena in the Sarawak River. The by-pass channel will operate during the high tides from the South China Sea and also during the heavy rain season especially January. The main objective is to studies modeling operation of the Flood diversion barrage in conjunction with the existing Kuching barrage during the heavy rain season o f Sarawak River.
1.4 Scope of work
The Inforworks River Stimulation(RS) version 9.0, a Wallingford software model will be applied to studies of the by-pass channel as an alternative way to prevent the flood occurs in the kuching town area especially to the batu tiga, batu kawa, and matang area. Inserting flood events data the software and run the river stimulation for the by-pass channel together in conjunction with the kuching barrage during the high tides events.
6
CHAPTER 2
LITERATURE REVIEW
2.1 Flooding
A flood is an overflow or accumulation of an expanse of water that submerges land. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Flooding is the primary hazard that occurred in all over the universe especially to our country. This may result from the volume of water within a body of water, such as a river or lake, which overflows or breaks levees, with the result that some of the water escapes its normal boundaries. While the size of a lake or other body of water will vary with seasonal changes in precipitation and snow melt, it is not a significant flood unless such escapes of water endanger land areas used by man like a village, city or other inhabited area.
In the case, the kuching city experience where the city area is situated in the middle of the river and the sea, the flood will occurred when the high tide phenomena happen and it will causing the surrounding area where the river is not be able to carry the huge amount of water flows and the water will overflowing its bank.
